Science.gov

Sample records for access point detection

  1. Rogue Access Point Detection Using Innate Characteristics of the 802.11 MAC

    NASA Astrophysics Data System (ADS)

    Venkataraman, Aravind; Beyah, Raheem

    Attacks on wireless networks can be classified into two categories: external wireless and internal wired. In external wireless attacks, an attacker uses a wireless device to target the access point (AP), other wireless nodes or the communications on the network. In internal wired attacks, an attacker or authorized insider inserts an unauthorized (or rogue) AP into the wired backbone for malicious activity or misfeasance. This paper addresses detecting the internal wired attack of inserting rogue APs (RAPs) in a network by monitoring on the wiredside for characteristics of wireless traffic. We focus on two 802.11 medium access control (MAC) layer features as a means of fingerprinting wireless traffic in a wired network. In particular, we study the effect of the Distributed Coordination Function (DCF) and rate adaptation specifications on wireless traffic by observing their influence on arrival delays. By focusing on fundamental traits of wireless communications, unlike existing techniques, we demonstrate that it is possible to extract wireless components from a flow without having to train our system with network-specific wired and wireless traces. Unlike some existing anomaly based detection schemes, our approach is generic as it does not assume that the wired network is inherently faster than the wireless network, is effective for networks that do not have sample wireless traffic, and is independent of network speed/type/protocol. We evaluate our approach using experiments and simulations. Using a Bayesian classifier we show that we can correctly identify wireless traffic on a wired link with 86-90% accuracy. This coupled with an appropriate switch port policy allows the identification of RAPs.

  2. Subject Access Points in Electronic Retrieval.

    ERIC Educational Resources Information Center

    Hjorland, Birger; Nielsen, Lykke Kyllesbech

    2001-01-01

    Discussion of subject access points in databases concentrates on the broader theoretical perspective. Topics include technology-driven stages in the development of subject access points; a taxonomy of subject access points; document titles; abstracts; references and citations; full text; and descriptors, identifiers, classification codes, and…

  3. Detecting determinism from point processes

    NASA Astrophysics Data System (ADS)

    Andrzejak, Ralph G.; Mormann, Florian; Kreuz, Thomas

    2014-12-01

    The detection of a nonrandom structure from experimental data can be crucial for the classification, understanding, and interpretation of the generating process. We here introduce a rank-based nonlinear predictability score to detect determinism from point process data. Thanks to its modular nature, this approach can be adapted to whatever signature in the data one considers indicative of deterministic structure. After validating our approach using point process signals from deterministic and stochastic model dynamics, we show an application to neuronal spike trains recorded in the brain of an epilepsy patient. While we illustrate our approach in the context of temporal point processes, it can be readily applied to spatial point processes as well.

  4. Planetary system detection by POINTS

    NASA Technical Reports Server (NTRS)

    Reasenberg, Robert D.

    1993-01-01

    The final report and semiannual reports 1, 2, and 3 in response to the study of 'Planetary System Detection by POINTS' is presented. The grant covered the period from 15 Jun. 1988 through 31 Dec. 1989. The work during that period comprised the further development and refinement of the POINTS concept. The status of the POINTS development at the end of the Grant period was described by Reasenberg in a paper given at the JPL Workshop on Space Interferometry, 12-13 Mar. 1990, and distributed as CfA Preprint 3138. That paper, 'POINTS: a Small Astrometric Interferometer,' follows as Appendix-A. Our proposal P2276-7-09, dated July 1990, included a more detailed description of the state of the development of POINTS at the end of the tenure of Grant NAGW-1355. That proposal, which resulted in Grant NAGW-2497, is included by reference.

  5. Access Points to ERIC: An Update. ERIC Digest.

    ERIC Educational Resources Information Center

    Vaughn, B. J.; Eisenberg, Michael B.

    This digest describes the traditional, new, and emerging points of access to the ERIC system: (1) traditional print access; (2) online access through commercial vendors; (3) CD-ROM; and (4) ERIC Digests Online. Also described are services offered by the ERIC Clearinghouse on Information Resources (ERIC/IR) that provide access to the system--ERIC…

  6. Redundancy and Uniqueness of Subject Access Points in Online Catalogs.

    ERIC Educational Resources Information Center

    Xu, Hong; Lancaster, F. W.

    1998-01-01

    An analysis of 205 records in the OCLC Online Union Catalog (OLUC) found considerable duplication among subject access points provided by title, subject heading, and classification number fields. On average, only 4.12 unique access points were found per record. The results suggest that online catalogs might outperform card catalogs more in…

  7. Contextual view of Point Bonita Ridge, showing Bonita Ridge access ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of Point Bonita Ridge, showing Bonita Ridge access road retaining wall and location of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation (see stake at center left), camera facing north - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

  8. Recent Advances in Point-of-Access Water Quality Monitoring

    NASA Astrophysics Data System (ADS)

    Korostynska, O.; Arshak, K.; Velusamy, V.; Arshak, A.; Vaseashta, Ashok

    Clean water is one of our most valuable natural resources. In addition to providing safe drinking water it assures functional ecosystems that support fisheries and recreation. Human population growth and its associated increased demands on water pose risks to maintaining acceptable water quality. It is vital to assess source waters and the aquatic systems that receive inputs from industrial waste and sewage treatment plants, storm water systems, and runoff from urban and agricultural lands. Rapid and confident assessments of aquatic resources form the basis for sound environmental management. Current methods engaged in tracing the presence of various bacteria in water employ bulky laboratory equipment and are time consuming. Thus, real-time water quality monitoring is essential for National and International Health and Safety. Environmental water monitoring includes measurements of physical characteristics (e.g. pH, temperature, conductivity), chemical parameters (e.g. oxygen, alkalinity, nitrogen and phosphorus compounds), and abundance of certain biological taxa. Monitoring could also include assays of biological activity such as alkaline phosphatase, tests for toxins such as microcystins and direct measurements of pollutants such as heavy metals or hydrocarbons. Real time detection can significantly reduce the level of damage and also the cost to remedy the problem. This paper presents overview of state-of-the-art methods and devices used for point-of-access water quality monitoring and suggest further developments in this area.

  9. Energy-efficient technologies for point-to-point fiber access

    NASA Astrophysics Data System (ADS)

    Lee, Ka-Lun; Li, Jie; Chan, Chien Aun; Anthapadmanabhan, N. Prasanth; Chow, Hungkei (Keith)

    2015-12-01

    This article discusses the fundamental issues and the technologies to achieve an energy-efficient Gigabit-Ethernet point-to-point (PtP) fiber access network. To minimize the power consumption of PtP fiber access for long-term development, it is essential to optimize each of the network components such as optical transceiver, user network interface, Ethernet aggregator and also their modes of operation. Our analysis shows that the energy consumption of a PtP fiber access network using our proposed technologies can be up to 7.5 times lower than that of the 2010 technologies when a combination of appropriate technologies is applied.

  10. Multi-lane detection based on multiple vanishing points detection

    NASA Astrophysics Data System (ADS)

    Li, Chuanxiang; Nie, Yiming; Dai, Bin; Wu, Tao

    2015-03-01

    Lane detection plays a significant role in Advanced Driver Assistance Systems (ADAS) for intelligent vehicles. In this paper we present a multi-lane detection method based on multiple vanishing points detection. A new multi-lane model assumes that a single lane, which has two approximately parallel boundaries, may not parallel to others on road plane. Non-parallel lanes associate with different vanishing points. A biological plausibility model is used to detect multiple vanishing points and fit lane model. Experimental results show that the proposed method can detect both parallel lanes and non-parallel lanes.

  11. Change Point Detection in Correlation Networks.

    PubMed

    Barnett, Ian; Onnela, Jukka-Pekka

    2016-01-07

    Many systems of interacting elements can be conceptualized as networks, where network nodes represent the elements and network ties represent interactions between the elements. In systems where the underlying network evolves, it is useful to determine the points in time where the network structure changes significantly as these may correspond to functional change points. We propose a method for detecting change points in correlation networks that, unlike previous change point detection methods designed for time series data, requires minimal distributional assumptions. We investigate the difficulty of change point detection near the boundaries of the time series in correlation networks and study the power of our method and competing methods through simulation. We also show the generalizable nature of the method by applying it to stock price data as well as fMRI data.

  12. From Access Points to Materials: A Transaction Log Analysis of Access Point Value for Online Catalog Users.

    ERIC Educational Resources Information Center

    Wyly, Brendan J.

    1996-01-01

    Describes a study that investigated the value of various access points in online catalog records by determining their usefulness to searchers who requested location information for items. Results of a transaction log analysis of the Illinois Library Computer Systems Office online union catalog for 45 academic libraries are discussed. (LRW)

  13. Single-Point Access to Data Distributed on Many Processors

    NASA Technical Reports Server (NTRS)

    James, Mark

    2007-01-01

    A description of the functions and data structures is defined that would be necessary to implement the Chapel concept of distributions, domains, allocation, access, and interfaces to the compiler for transformations from Chapel source to their run-time implementation for these concepts. A complete set of object-oriented operators is defined that enables one to access elements of a distributed array through regular arithmetic index sets, giving the programmer the illusion that all the elements are collocated on a single processor. This means that arbitrary regions of the arrays can be fragmented and distributed across multiple processors with a single point of access. This is important because it can significantly improve programmer productivity by allowing the programmers to concentrate on the high-level details of the algorithm without worrying about the efficiency and communication details of the underlying representation.

  14. Accessing the exceptional points of parity-time symmetric acoustics.

    PubMed

    Shi, Chengzhi; Dubois, Marc; Chen, Yun; Cheng, Lei; Ramezani, Hamidreza; Wang, Yuan; Zhang, Xiang

    2016-01-01

    Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. The manipulation of exceptional points offers new routes to broaden applications for PT symmetric physics in acoustics, optics, microwaves and electronics, which are essential for sensing, communication and imaging. PMID:27025443

  15. Accessing the exceptional points of parity-time symmetric acoustics.

    PubMed

    Shi, Chengzhi; Dubois, Marc; Chen, Yun; Cheng, Lei; Ramezani, Hamidreza; Wang, Yuan; Zhang, Xiang

    2016-01-01

    Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. The manipulation of exceptional points offers new routes to broaden applications for PT symmetric physics in acoustics, optics, microwaves and electronics, which are essential for sensing, communication and imaging.

  16. Accessing the exceptional points of parity-time symmetric acoustics

    PubMed Central

    Shi, Chengzhi; Dubois, Marc; Chen, Yun; Cheng, Lei; Ramezani, Hamidreza; Wang, Yuan; Zhang, Xiang

    2016-01-01

    Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. The manipulation of exceptional points offers new routes to broaden applications for PT symmetric physics in acoustics, optics, microwaves and electronics, which are essential for sensing, communication and imaging. PMID:27025443

  17. Accessing the exceptional points of parity-time symmetric acoustics

    NASA Astrophysics Data System (ADS)

    Shi, Chengzhi; Dubois, Marc; Chen, Yun; Cheng, Lei; Ramezani, Hamidreza; Wang, Yuan; Zhang, Xiang

    2016-03-01

    Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. The manipulation of exceptional points offers new routes to broaden applications for PT symmetric physics in acoustics, optics, microwaves and electronics, which are essential for sensing, communication and imaging.

  18. Point source detection in infrared astronomical surveys

    NASA Technical Reports Server (NTRS)

    Pelzmann, R. F., Jr.

    1977-01-01

    Data processing techniques useful for infrared astronomy data analysis systems are reported. This investigation is restricted to consideration of data from space-based telescope systems operating as survey instruments. In this report the theoretical background for specific point-source detection schemes is completed, and the development of specific algorithms and software for the broad range of requirements is begun.

  19. Animal Detection Precedes Access to Scene Category

    PubMed Central

    Crouzet, Sébastien M.; Joubert, Olivier R.; Thorpe, Simon J.; Fabre-Thorpe, Michèle

    2012-01-01

    The processes underlying object recognition are fundamental for the understanding of visual perception. Humans can recognize many objects rapidly even in complex scenes, a task that still presents major challenges for computer vision systems. A common experimental demonstration of this ability is the rapid animal detection protocol, where human participants earliest responses to report the presence/absence of animals in natural scenes are observed at 250–270 ms latencies. One of the hypotheses to account for such speed is that people would not actually recognize an animal per se, but rather base their decision on global scene statistics. These global statistics (also referred to as spatial envelope or gist) have been shown to be computationally easy to process and could thus be used as a proxy for coarse object recognition. Here, using a saccadic choice task, which allows us to investigate a previously inaccessible temporal window of visual processing, we showed that animal – but not vehicle – detection clearly precedes scene categorization. This asynchrony is in addition validated by a late contextual modulation of animal detection, starting simultaneously with the availability of scene category. Interestingly, the advantage for animal over scene categorization is in opposition to the results of simulations using standard computational models. Taken together, these results challenge the idea that rapid animal detection might be based on early access of global scene statistics, and rather suggests a process based on the extraction of specific local complex features that might be hardwired in the visual system. PMID:23251545

  20. Access point selection game with mobile users using correlated equilibrium.

    PubMed

    Sohn, Insoo

    2015-01-01

    One of the most important issues in wireless local area network (WLAN) systems with multiple access points (APs) is the AP selection problem. Game theory is a mathematical tool used to analyze the interactions in multiplayer systems and has been applied to various problems in wireless networks. Correlated equilibrium (CE) is one of the powerful game theory solution concepts, which is more general than the Nash equilibrium for analyzing the interactions in multiplayer mixed strategy games. A game-theoretic formulation of the AP selection problem with mobile users is presented using a novel scheme based on a regret-based learning procedure. Through convergence analysis, we show that the joint actions based on the proposed algorithm achieve CE. Simulation results illustrate that the proposed algorithm is effective in a realistic WLAN environment with user mobility and achieves maximum system throughput based on the game-theoretic formulation. PMID:25785726

  1. Simple road detection based on vanishing point

    NASA Astrophysics Data System (ADS)

    Ziyu, Chen; Zhen, He

    2014-05-01

    Vision-based road detection is one of the key techniques of autonomous driving, intelligent vehicles, and visual navigation. At present, methods based on vanishing point perform best with general roads. However, it is difficult for them to meet the needs of a real-time system due to high time consumption. This paper presents a fast detection method, namely simple road detection, which achieves high efficiency by employing sky segmentation and two new optimization schemes-sample convolution and fast voting. The optimizations are based on lookup tables, sample computing, and computing simplification. The interval sampling in sample convolution makes the proposed method flexible to meet various efficiency and accuracy demands by different sample-step values. Mean filter and vote orientation limitation are also proposed to help improve detection accuracy. Experiments have been conducted with a large number of road images under different environmental conditions, and the results demonstrate that our proposed method is efficient and effective in detecting both structured and unstructured roads.

  2. Atomicity violation detection using access interleaving invariants

    DOEpatents

    Zhou, Yuanyuan; Lu, Shan; Tucek, Joseph Andrew

    2013-09-10

    During execution of a program, the situation where the atomicity of a pair of instructions that are to be executed atomically is violated is identified, and a bug is detected as occurring in the program at the pair of instructions. The pairs of instructions that are to be executed atomically can be identified in different manners, such as by executing a program multiple times and using the results of those executions to automatically identify the pairs of instructions.

  3. Detection and response to unauthorized access to a communication device

    DOEpatents

    Smith, Rhett; Gordon, Colin

    2015-09-08

    A communication gateway consistent with the present disclosure may detect unauthorized physical or electronic access and implement security actions in response thereto. A communication gateway may provide a communication path to an intelligent electronic device (IED) using an IED communications port configured to communicate with the IED. The communication gateway may include a physical intrusion detection port and a network port. The communication gateway may further include control logic configured to evaluate physical intrusion detection signal. The control logic may be configured to determine that the physical intrusion detection signal is indicative of an attempt to obtain unauthorized access to one of the communication gateway, the IED, and a device in communication with the gateway; and take a security action based upon the determination that the indication is indicative of the attempt to gain unauthorized access.

  4. Wafer weak point detection based on aerial images or WLCD

    NASA Astrophysics Data System (ADS)

    Ning, Guoxiang; Philipp, Peter; Litt, Lloyd C.; Ackmann, Paul; Crell, Christian; Chen, Norman

    2015-10-01

    Aerial image measurement is a key technique for model based optical proximity correction (OPC) verification. Actual aerial images obtained by AIMS (aerial image measurement system) or WLCD (wafer level critical dimension) can detect printed wafer weak point structures in advance of wafer exposure and defect inspection. Normally, the potential wafer weak points are determined based on optical rule check (ORC) simulation in advance. However, the correlation to real wafer weak points is often not perfect due to the contribution of mask three dimension (M3D) effects, actual mask errors, and scanner lens effects. If the design weak points can accurately be detected in advance, it will reduce the wafer fab cost and improve cycle time. WLCD or AIMS tools are able to measure the aerial images CD and bossung curve through focus window. However, it is difficult to detect the wafer weak point in advance without defining selection criteria. In this study, wafer weak points sensitive to mask mean-to-nominal values are characterized for a process with very high MEEF (normally more than 4). Aerial image CD uses fixed threshold to detect the wafer weak points. By using WLCD through threshold and focus window, the efficiency of wafer weak point detection is also demonstrated. A novel method using contrast range evaluation is shown in the paper. Use of the slope of aerial images for more accurate detection of the wafer weak points using WLCD is also discussed. The contrast range can also be used to detect the wafer weak points in advance. Further, since the mean to nominal of the reticle contributes to the effective contrast range in a high MEEF area this work shows that control of the mask error is critical for high MEEF layers such as poly, active and metal layers. Wafer process based weak points that cannot be detected by wafer lithography CD or WLCD will be discussed.

  5. Fast Change Point Detection for Electricity Market Analysis

    SciTech Connect

    Berkeley, UC; Gu, William; Choi, Jaesik; Gu, Ming; Simon, Horst; Wu, Kesheng

    2013-08-25

    Electricity is a vital part of our daily life; therefore it is important to avoid irregularities such as the California Electricity Crisis of 2000 and 2001. In this work, we seek to predict anomalies using advanced machine learning algorithms. These algorithms are effective, but computationally expensive, especially if we plan to apply them on hourly electricity market data covering a number of years. To address this challenge, we significantly accelerate the computation of the Gaussian Process (GP) for time series data. In the context of a Change Point Detection (CPD) algorithm, we reduce its computational complexity from O($n^{5}$) to O($n^{2}$). Our efficient algorithm makes it possible to compute the Change Points using the hourly price data from the California Electricity Crisis. By comparing the detected Change Points with known events, we show that the Change Point Detection algorithm is indeed effective in detecting signals preceding major events.

  6. GENESI-DR - A single access point to Earth Science data

    NASA Astrophysics Data System (ADS)

    Cossu, R.; Goncalves, P.; Pacini, F.

    2009-04-01

    .) and will adhere to a common set of standards / policies / interfaces. The end-users will be provided with a virtual collection of digital Earth Science data, irrespectively of their location in the various single federated repositories. GENESI-DR objectives have lead to the identification of the basic GENESI-DR infrastructure requirements: • Capability, for Earth Science users, to discover data from different European Earth Science Digital Repositories through the same interface in a transparent and homogeneous way; • Easiness and speed of access to large volumes of coherently maintained distributed data in an effective and timely way; • Capability, for DR owners, to easily make available their data to a significantly increased audience with no need to duplicate them in a different storage system. Data discovery is based on a Central Discovery Service, which allows users and applications to easily query information about data collections and products existing in heterogeneous catalogues, at federated DR sites. This service can be accessed by users via web interface, the GENESI-DR Web Portal, or by external applications via open standardized interfaces exposed by the system. The Central Discovery Service identifies the DRs providing products complying with the user search criteria and returns the corresponding access points to the requester. By taking into consideration different and efficient data transfer technologies such as HTTPS, GridFTP and BitTorrent, the infrastructure provides easiness and speed of access. Conversely, for data publishing GENESI-DR provides several mechanisms to assist DR owners in producing a metadata catalogues. In order to reach its objectives, the GENESI-DR e-Infrastructure will be validated against user needs for accessing and sharing Earth Science data. Initially, four specific applications in the land, atmosphere and marine domains have been selected, including: • Near real time orthorectification for agricultural crops

  7. Testing the importance of auditory detections in avian point counts

    USGS Publications Warehouse

    Brewster, J.P.; Simons, T.R.

    2009-01-01

    Recent advances in the methods used to estimate detection probability during point counts suggest that the detection process is shaped by the types of cues available to observers. For example, models of the detection process based on distance-sampling or time-of-detection methods may yield different results for auditory versus visual cues because of differences in the factors that affect the transmission of these cues from a bird to an observer or differences in an observer's ability to localize cues. Previous studies suggest that auditory detections predominate in forested habitats, but it is not clear how often observers hear birds prior to detecting them visually. We hypothesized that auditory cues might be even more important than previously reported, so we conducted an experiment in a forested habitat in North Carolina that allowed us to better separate auditory and visual detections. Three teams of three observers each performed simultaneous 3-min unlimited-radius point counts at 30 points in a mixed-hardwood forest. One team member could see, but not hear birds, one could hear, but not see, and the third was nonhandicapped. Of the total number of birds detected, 2.9% were detected by deafened observers, 75.1% by blinded observers, and 78.2% by nonhandicapped observers. Detections by blinded and nonhandicapped observers were the same only 54% of the time. Our results suggest that the detection of birds in forest habitats is almost entirely by auditory cues. Because many factors affect the probability that observers will detect auditory cues, the accuracy and precision of avian point count estimates are likely lower than assumed by most field ornithologists. ?? 2009 Association of Field Ornithologists.

  8. Point target detection using super-resolution reconstruction

    NASA Astrophysics Data System (ADS)

    Dijk, Judith; van Eekeren, Adam W. M.; Schutte, Klamer; de Lange, Dirk-Jan J.

    2007-04-01

    Surveillance applications are primarily concerned with detection of targets. In electro-optical surveillance systems, missiles or other weapons coming towards you are observed as moving points. Typically, such moving targets need to be detected in a very short time. One of the problems is that the targets will have a low signal-to-noise ratio with respect to the background, and that the background can be severely cluttered like in an air-to-ground scenario. The first step in detection of point targets is to suppress the background. The novelty of this work is that a super-resolution reconstruction algorithm is used in the background suppression step. It is well-known that super-resolution reconstruction reduces the aliasing in the image. This anti-aliasing is used to model the specific aliasing contribution in the camera image, which results in a better estimate of the clutter in the background. Using super-resolution reconstruction also reduces the temporal noise, thus providing a better signal-to-noise ratio than the camera images. After the background suppression step common detection algorithms such as thresholding or track-before-detect can be used. Experimental results are given which show that the use of super-resolution reconstruction significantly increases the sensitivity of the point target detection. The detection of the point targets is increased by the noise reduction property of the super-resolution reconstruction algorithm. The background suppression is improved by the anti-aliasing.

  9. Research on immune storage anomaly detection via user access behavior

    NASA Astrophysics Data System (ADS)

    Huang, Jianzhong; Chen, Yunliang; Fang, Yunfu

    2008-12-01

    If an intruder uses a stolen account, the authentication sub-system will regard the intruder as a legitimate user. In order to filter out such illegal users, the storage system should be capable of the user activity diagnosis. This paper presents a novel anomaly detection scheme to monitor the user access activities using the artificial immune technique. When an access request violates the access control rule, it is regarded as Non-self, so as to provide some early warning tips to the storage security sub-system. Compared with the NIDS, the proposed scheme targets the anomaly detection at storage level and focuses on the read/write data requests. In the prophase of simulation, a set of optimal parameters of algorithm are fitted according to the mean convergence speed and detection efficiency. The simulation shows the proposed scheme can reach rather high detection rate and low false alarm rate, further validating its feasibility. Thus the storage anomaly detection would strengthen the storage early warning and improve the storage security.

  10. Retina-on-a-chip: a microfluidic platform for point access signaling studies

    PubMed Central

    Dodson, Kirsten H.; Echevarria, Franklin D.; Li, Deyu; Sappington, Rebecca M.; Edd, Jon F.

    2016-01-01

    We report on a microfluidic platform for culture of whole organs or tissue slices with the capability of point access reagent delivery to probe the transport of signaling events. Whole mice retina were maintained for multiple days with negative pressure applied to tightly but gently bind the bottom of the retina to a thin poly-(dimethylsiloxane) membrane, through which twelve 100 μm diameter through-holes served as fluidic access points. Staining with toluidine blue, transport of locally applied cholera toxin beta, and transient response to lipopolysaccharide in the retina demonstrated the capability of the microfluidic platform. The point access fluidic delivery capability could enable new assays in the study of various kinds of excised tissues, including retina. PMID:26559199

  11. Change-point detection for recursive Bayesian geoacoustic inversions.

    PubMed

    Tan, Bien Aik; Gerstoft, Peter; Yardim, Caglar; Hodgkiss, William S

    2015-04-01

    In order to carry out geoacoustic inversion in low signal-to-noise ratio (SNR) conditions, extended duration observations coupled with source and/or receiver motion may be necessary. As a result, change in the underlying model parameters due to time or space is anticipated. In this paper, an inversion method is proposed for cases when the model parameters change abruptly or slowly. A model parameter change-point detection method is developed to detect the change in the model parameters using the importance samples and corresponding weights that are already available from the recursive Bayesian inversion. If the model parameters change abruptly, a change-point will be detected and the inversion will restart with the pulse measurement after the change-point. If the model parameters change gradually, the inversion (based on constant model parameters) may proceed until the accumulated model parameter mismatch is significant and triggers the detection of a change-point. These change-point detections form the heuristics for controlling the coherent integration time in recursive Bayesian inversion. The method is demonstrated in simulation with parameters corresponding to the low SNR, 100-900 Hz linear frequency modulation pulses observed in the Shallow Water 2006 experiment [Tan, Gerstoft, Yardim, and Hodgkiss, J. Acoust. Soc. Am. 136, 1187-1198 (2014)].

  12. Street environment change detection from mobile laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Xiao, Wen; Vallet, Bruno; Brédif, Mathieu; Paparoditis, Nicolas

    2015-09-01

    Mobile laser scanning (MLS) has become a popular technique for road inventory, building modelling, infrastructure management, mobility assessment, etc. Meanwhile, due to the high mobility of MLS systems, it is easy to revisit interested areas. However, change detection using MLS data of street environment has seldom been studied. In this paper, an approach that combines occupancy grids and a distance-based method for change detection from MLS point clouds is proposed. Unlike conventional occupancy grids, our occupancy-based method models space based on scanning rays and local point distributions in 3D without voxelization. A local cylindrical reference frame is presented for the interpolation of occupancy between rays according to the scanning geometry. The Dempster-Shafer theory (DST) is utilized for both intra-data evidence fusion and inter-data consistency assessment. Occupancy of reference point cloud is fused at the location of target points and then the consistency is evaluated directly on the points. A point-to-triangle (PTT) distance-based method is combined to improve the occupancy-based method. Because it is robust to penetrable objects, e.g. vegetation, which cause self-conflicts when modelling occupancy. The combined method tackles irregular point density and occlusion problems, also eliminates false detections on penetrable objects.

  13. Automatic Detection of Building Points from LIDAR and Dense Image Matching Point Clouds

    NASA Astrophysics Data System (ADS)

    Maltezos, E.; Ioannidis, C.

    2015-08-01

    This study aims to detect automatically building points: (a) from LIDAR point cloud using simple techniques of filtering that enhance the geometric properties of each point, and (b) from a point cloud which is extracted applying dense image matching at high resolution colour-infrared (CIR) digital aerial imagery using the stereo method semi-global matching (SGM). At first step, the removal of the vegetation is carried out. At the LIDAR point cloud, two different methods are implemented and evaluated using initially the normals and the roughness values afterwards: (1) the proposed scan line smooth filtering and a thresholding process, and (2) a bilateral filtering and a thresholding process. For the case of the CIR point cloud, a variation of the normalized differential vegetation index (NDVI) is computed for the same purpose. Afterwards, the bare-earth is extracted using a morphological operator and removed from the rest scene so as to maintain the buildings points. The results of the extracted buildings applying each approach at an urban area in northern Greece are evaluated using an existing orthoimage as reference; also, the results are compared with the corresponding classified buildings extracted from two commercial software. Finally, in order to verify the utility and functionality of the extracted buildings points that achieved the best accuracy, the 3D models in terms of Level of Detail 1 (LoD 1) and a 3D building change detection process are indicatively performed on a sub-region of the overall scene.

  14. Automated design of image operators that detect interest points.

    PubMed

    Trujillo, Leonardo; Olague, Gustavo

    2008-01-01

    This work describes how evolutionary computation can be used to synthesize low-level image operators that detect interesting points on digital images. Interest point detection is an essential part of many modern computer vision systems that solve tasks such as object recognition, stereo correspondence, and image indexing, to name but a few. The design of the specialized operators is posed as an optimization/search problem that is solved with genetic programming (GP), a strategy still mostly unexplored by the computer vision community. The proposed approach automatically synthesizes operators that are competitive with state-of-the-art designs, taking into account an operator's geometric stability and the global separability of detected points during fitness evaluation. The GP search space is defined using simple primitive operations that are commonly found in point detectors proposed by the vision community. The experiments described in this paper extend previous results (Trujillo and Olague, 2006a,b) by presenting 15 new operators that were synthesized through the GP-based search. Some of the synthesized operators can be regarded as improved manmade designs because they employ well-known image processing techniques and achieve highly competitive performance. On the other hand, since the GP search also generates what can be considered as unconventional operators for point detection, these results provide a new perspective to feature extraction research.

  15. Automated design of image operators that detect interest points.

    PubMed

    Trujillo, Leonardo; Olague, Gustavo

    2008-01-01

    This work describes how evolutionary computation can be used to synthesize low-level image operators that detect interesting points on digital images. Interest point detection is an essential part of many modern computer vision systems that solve tasks such as object recognition, stereo correspondence, and image indexing, to name but a few. The design of the specialized operators is posed as an optimization/search problem that is solved with genetic programming (GP), a strategy still mostly unexplored by the computer vision community. The proposed approach automatically synthesizes operators that are competitive with state-of-the-art designs, taking into account an operator's geometric stability and the global separability of detected points during fitness evaluation. The GP search space is defined using simple primitive operations that are commonly found in point detectors proposed by the vision community. The experiments described in this paper extend previous results (Trujillo and Olague, 2006a,b) by presenting 15 new operators that were synthesized through the GP-based search. Some of the synthesized operators can be regarded as improved manmade designs because they employ well-known image processing techniques and achieve highly competitive performance. On the other hand, since the GP search also generates what can be considered as unconventional operators for point detection, these results provide a new perspective to feature extraction research. PMID:19053496

  16. Subject Access Points in the MARC Record and Archival Finding Aid: Enough or Too Many?

    ERIC Educational Resources Information Center

    Cox, Elizabeth; Czechowski, Leslie

    2007-01-01

    In this research project, the authors set out to discover the current practice in both the archival and cataloging worlds for usage of access points in descriptive records and to learn how archival descriptive practices fit into long-established library cataloging procedures and practices. A sample of archival finding aids and MARC records at 123…

  17. Development of Curie point switching for thin film, random access, memory device

    NASA Technical Reports Server (NTRS)

    Lewicki, G. W.; Tchernev, D. I.

    1967-01-01

    Managanese bismuthide films are used in the development of a random access memory device of high packing density and nondestructive readout capability. Memory entry is by Curie point switching using a laser beam. Readout is accomplished by microoptical or micromagnetic scanning.

  18. 46 CFR 188.10-56 - Pilot boarding equipment and point of access.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pilot boarding equipment and point of access. 188.10-56 Section 188.10-56 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH... deck of a vessel where a person steps onto or off of pilot boarding equipment....

  19. Public Internet Access Points (PIAPs) and Their Social Impact: A Case Study from Turkey

    ERIC Educational Resources Information Center

    Afacan, Gulgun; Er, Erkan; Arifoglu, Ali

    2013-01-01

    Building public Internet access points (PIAPs) is a significant contribution of governments towards achieving an information society. While many developing countries are investing great amounts to establish PIAPs today, people may not use PIAPs effectively. Yet, the successful implementation of PIAPs is the result of citizens' acceptance to use…

  20. An antenna-pointing mechanism for the ETS-6 K-band Single Access (KSA) antenna

    NASA Technical Reports Server (NTRS)

    Takada, Noboru; Amano, Takahiro; Ohhashi, Toshiro; Wachi, Shigeo

    1991-01-01

    Both the design philosophy for the Antenna Pointing Mechanism (APM) to be used for the K-band Single Access (KSA) antenna system and experimental results of the APM Engineering Model (EM) tests are described. The KSA antenna system will be flown on the Engineering Test Satellite 6 (ETS-6).

  1. Change-point models to estimate the limit of detection.

    PubMed

    May, Ryan C; Chu, Haitao; Ibrahim, Joseph G; Hudgens, Michael G; Lees, Abigail C; Margolis, David M

    2013-12-10

    In many biological and environmental studies, measured data is subject to a limit of detection. The limit of detection is generally defined as the lowest concentration of analyte that can be differentiated from a blank sample with some certainty. Data falling below the limit of detection is left censored, falling below a level that is easily quantified by a measuring device. A great deal of interest lies in estimating the limit of detection for a particular measurement device. In this paper, we propose a change-point model to estimate the limit of detection by using data from an experiment with known analyte concentrations. Estimation of the limit of detection proceeds by a two-stage maximum likelihood method. Extensions are considered that allow for censored measurements and data from multiple experiments. A simulation study is conducted demonstrating that in some settings the change-point model provides less biased estimates of the limit of detection than conventional methods. The proposed method is then applied to data from an HIV pilot study.

  2. Jump point detection for real estate investment success

    NASA Astrophysics Data System (ADS)

    Hui, Eddie C. M.; Yu, Carisa K. W.; Ip, Wai-Cheung

    2010-03-01

    In the literature, studies on real estate market were mainly concentrating on the relation between property price and some key factors. The trend of the real estate market is a major concern. It is believed that changes in trend are signified by some jump points in the property price series. Identifying such jump points reveals important findings that enable policy-makers to look forward. However, not all jump points are observable from the plot of the series. This paper looks into the trend and introduces a new approach to the framework for real estate investment success. The main purpose of this paper is to detect jump points in the time series of some housing price indices and stock price index in Hong Kong by applying the wavelet analysis. The detected jump points reflect to some significant political issues and economic collapse. Moreover, the relations among properties of different classes and between stocks and properties are examined. It can be shown from the empirical result that a lead-lag effect happened between the prices of large-size property and those of small/medium-size property. However, there is no apparent relation or consistent lead in terms of change point measure between property price and stock price. This may be due to the fact that globalization effect has more impact on the stock price than the property price.

  3. Point detection of bacterial and viral pathogens using oral samples

    NASA Astrophysics Data System (ADS)

    Malamud, Daniel

    2008-04-01

    Oral samples, including saliva, offer an attractive alternative to serum or urine for diagnostic testing. This is particularly true for point-of-use detection systems. The various types of oral samples that have been reported in the literature are presented here along with the wide variety of analytes that have been measured in saliva and other oral samples. The paper focuses on utilizing point-detection of infectious disease agents, and presents work from our group on a rapid test for multiple bacterial and viral pathogens by monitoring a series of targets. It is thus possible in a single oral sample to identify multiple pathogens based on specific antigens, nucleic acids, and host antibodies to those pathogens. The value of such a technology for detecting agents of bioterrorism at remote sites is discussed.

  4. Vehicle Localization by LIDAR Point Correlation Improved by Change Detection

    NASA Astrophysics Data System (ADS)

    Schlichting, A.; Brenner, C.

    2016-06-01

    LiDAR sensors are proven sensors for accurate vehicle localization. Instead of detecting and matching features in the LiDAR data, we want to use the entire information provided by the scanners. As dynamic objects, like cars, pedestrians or even construction sites could lead to wrong localization results, we use a change detection algorithm to detect these objects in the reference data. If an object occurs in a certain number of measurements at the same position, we mark it and every containing point as static. In the next step, we merge the data of the single measurement epochs to one reference dataset, whereby we only use static points. Further, we also use a classification algorithm to detect trees. For the online localization of the vehicle, we use simulated data of a vertical aligned automotive LiDAR sensor. As we only want to use static objects in this case as well, we use a random forest classifier to detect dynamic scan points online. Since the automotive data is derived from the LiDAR Mobile Mapping System, we are able to use the labelled objects from the reference data generation step to create the training data and further to detect dynamic objects online. The localization then can be done by a point to image correlation method using only static objects. We achieved a localization standard deviation of about 5 cm (position) and 0.06° (heading), and were able to successfully localize the vehicle in about 93 % of the cases along a trajectory of 13 km in Hannover, Germany.

  5. Early Detection and Treatment of Hemodialysis Access Dysfunction

    SciTech Connect

    Gallego Beuter, Juan Jose; Hernandez Lezana, Antonio

    2000-01-15

    Purpose: To assess the usefulness of a program for the early detection of hemodialysis graft dysfunction and the impact on graft survival of percutaneous transluminal angioplasty (PTA) and stent implantation to correct venous stenosis.Methods: A program for the early detection of hemodialysis access graft dysfunction was carried out in 110 patients over a period of 80 months. Detection was based on physical examination, flow rate measurements, venous pressure, and analytical determinations performed at dialysis. The stenoses detected were treated by PTA or PTA plus stent deployment. Survival curves compared primary and assisted patency rates for the different graft types.Results: The most important indicators of dysfunction were increased venous pressure and difficulty in cannulation of the graft. Significant stenoses were revealed by 227 (92.2%) of the 246 fistulography procedures performed. PTA results were satisfactory in 100% of the Thomas grafts, 74% of the Brescia-Cimino (BC) grafts, and 53% of the polytetrafluoroethylene (PTFE) grafts. Technical success rates for stent deployment were 92% for BC grafts and 100% for PTFE grafts, while functional success rates were 96% and 97%, respectively. The difference in the primary patency (P1) and assisted patency (AP) values was statistically significant for all three graft types. There was no significant difference in the patency rates for grafts treated by PTA alone or by PTA and stent deployment.Conclusion: A surveillance program helped prevent graft thrombosis, and intervention as required achieved excellent primary and assisted patency rates. Stent deployment salvaged a considerable number of accesses but did not significantly extend access survival time.

  6. Detection of clustered microcalcifications using spatial point process modeling

    NASA Astrophysics Data System (ADS)

    Jing, Hao; Yang, Yongyi; Nishikawa, Robert M.

    2011-01-01

    In this work we propose a spatial point process (SPP) approach to improve the detection accuracy of clustered microcalcifications (MCs) in mammogram images. The conventional approach to MC detection has been to first detect the individual MCs in an image independently, which are subsequently grouped into clusters. Our proposed approach aims to exploit the spatial distribution among the different MCs in a mammogram image (i.e. MCs tend to appear in small clusters) directly during the detection process. We model the MCs by a marked point process (MPP) in which spatially neighboring MCs interact with each other. The MCs are then simultaneously detected through maximum a posteriori (MAP) estimation of the model parameters associated with the MPP process. The proposed approach was evaluated with a dataset of 141 clinical mammograms from 66 cases, and the results show that it could yield improved detection performance compared to a recently proposed support vector machine (SVM) detector. In particular, the proposed approach achieved a sensitivity of about 90% with the FP rate at around 0.5 clusters per image, compared to about 83% for the SVM; the performance of the proposed approach was also demonstrated to be more stable over different compositions of the test images. This work was supported by NIH/NIBIB grant R01EB009905.

  7. Detection of clustered microcalcifications using spatial point process modeling

    PubMed Central

    Jing, Hao; Yang, Yongyi; Nishikawa, Robert M.

    2011-01-01

    In this work we propose a spatial point process (SPP) approach to improve the detection accuracy of clustered microcalcifications (MCs) in mammogram images. The conventional approach to MC detection has been to first detect the individual MCs in an image independently, which are subsequently grouped into clusters. Our proposed approach aims to exploit the spatial distribution among the different MCs in a mammogram image (i.e., MCs tend to appear in small clusters) directly during the detection process. We model the MCs by a marked point process (MPP) in which spatially neighboring MCs interact with each other. The MCs are then simultaneously detected through maximum a posteriori (MAP) estimation of the model parameters associated with the MPP process. The proposed approach was evaluated with a dataset of 141 clinical mammograms from 66 cases, and the results show that it could yield improved detection performance compared to a recently proposed SVM detector. In particular, the proposed approach achieved a sensitivity of about 90% with the FP rate at around 0.5 clusters per image, compared to about 83% for the SVM; the performance of the proposed approach was also demonstrated to be more stable over different composition of the test images. PMID:21119233

  8. Laser desorption mass spectrometry for point mutation detection

    SciTech Connect

    Taranenko, N.I.; Chung, C.N.; Zhu, Y.F.

    1996-10-01

    A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments generated by digestion of a PCR generated target fragment. 21 refs., 10 figs., 2 tabs.

  9. Laser desorption mass spectrometry for point mutation detection

    SciTech Connect

    Taranenko, N.I.; Chung, C.N.; Zhu, Y.F.

    1996-12-31

    A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments by digestion of a PCR generated target fragment. 21 refs., 10 figs., 2 tabs.

  10. A micro dew point sensor with a thermal detection principle

    NASA Astrophysics Data System (ADS)

    Kunze, M.; Merz, J.; Hummel, W.-J.; Glosch, H.; Messner, S.; Zengerle, R.

    2012-01-01

    We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ~1 µm3) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of -20 °C (air temperature = 22 °C) the deviation increases to nearly -1 K.

  11. Neutral point detection by satellites. [magnetospheric neutral sheets

    NASA Technical Reports Server (NTRS)

    Schindler, K.; Ness, N. F.

    1974-01-01

    The concept of a neutral point depends on the physical phenomena described. The regions with B less than about 1 gamma detected by Schindler and Ness may be interpreted as neutral regions for the ion-tearing process. The assumption of the presence of a multiple neutral point structure (with temporal variations) is still the most promising interpretation of the Explorer 34 data. Alternatives suggested by Russell lead to difficulties. Nevertheless, the final answer can come only from multiple satellite systems. A 1-day displacement of the day count in the data discussed by Schindler and Ness is corrected.

  12. Modeling threshold detection and search for point and extended sources

    NASA Astrophysics Data System (ADS)

    Friedman, Melvin

    2016-05-01

    This paper deals with three separate topics. 1)The Berek extended object threshold detection model is described, calibrated against a portion of Blackwell's 1946 naked eye threshold detection data for extended objects against an unstructured background, and then the remainder of Blackwell's data is used to verify and validate the model. A range equation is derived from Berek's model which allows threshold detection range to be predicted for extended to point objects against an un-cluttered background as a function of target size and adapting luminance levels. The range equation is then used to model threshold detection of stationary reflective and self-luminous targets against an uncluttered background. 2) There is uncertainty whether Travnikova's search data for point source detection against an un-cluttered background is described by Rayleigh or exponential distributions. A model which explains the Rayleigh distribution for barely perceptible objects and the exponential distribution for brighter objects is given. 3) A technique is presented which allows a specific observer's target acquisition capability to be characterized. Then a model is presented which describes how individual target acquisition probability grows when a specific observer or combination of specific observers search for targets. Applications for the three topics are discussed.

  13. Infrared detection with point contact-metal semiconductor diodes

    NASA Astrophysics Data System (ADS)

    Eisenstein, G.

    1980-03-01

    Point contact Schottky barrier diodes, operating as video detectors and harmonic mixers at infrared frequencies, are studied, and theoretical models are developed and tested. A model extending the frequency response of the nonlinear barrier into the infrared is developed. Conductive and capacitive detection in highly doped semiconductors is considered. A model in which the low frequency spreading resistance is replaced by a complex spreading impedance is developed. The model predicts that optimal operation requires a semiconductor whose plasma frequency is one-third the operation frequency. Physical processes taking place simultaneously in the active region and in general thermal in nature are investigated. A thermo-electric detection model is developed and confirmed experimentally. The manufacturing of bulk point contact diodes is described in detail. Experimental results are compared with theoretical predictions. A method for producing thin crystaline semiconducting films on a metallic substrate is described.

  14. Fragmentation Point Detection of JPEG Images at DHT Using Validator

    NASA Astrophysics Data System (ADS)

    Mohamad, Kamaruddin Malik; Deris, Mustafa Mat

    File carving is an important, practical technique for data recovery in digital forensics investigation and is particularly useful when filesystem metadata is unavailable or damaged. The research on reassembly of JPEG files with RST markers, fragmented within the scan area have been done before. However, fragmentation within Define Huffman Table (DHT) segment is yet to be resolved. This paper analyzes the fragmentation within the DHT area and list out all the fragmentation possibilities. Two main contributions are made in this paper. Firstly, three fragmentation points within DHT area are listed. Secondly, few novel validators are proposed to detect these fragmentations. The result obtained from tests done on manually fragmented JPEG files, showed that all three fragmentation points within DHT are successfully detected using validators.

  15. Position Estimation of Access Points in 802.11 Wireless Networks

    SciTech Connect

    Kent, C A; Dowla, F U; Atwal, P K; Lennon, W J

    2003-12-05

    We developed a technique to locate wireless network nodes using multiple time-of-flight range measurements in a position estimate. When used with communication methods that allow propagation through walls, such as Ultra-Wideband and 802.11, we can locate network nodes in buildings and in caves where GPS is unavailable. This paper details the implementation on an 802.11a network where we demonstrated the ability to locate a network access point to within 20 feet.

  16. Efficient detection and recognition algorithm of reference points in photogrammetry

    NASA Astrophysics Data System (ADS)

    Li, Weimin; Liu, Gang; Zhu, Lichun; Li, Xiaofeng; Zhang, Yuhai; Shan, Siyu

    2016-04-01

    In photogrammetry, an approach of automatic detection and recognition on reference points have been proposed to meet the requirements on detection and matching of reference points. The reference points used here are the CCT(circular coded target), which compose of two parts: the round target point in central region and the circular encoding band in surrounding region. Firstly, the contours of image are extracted, after that noises and disturbances of the image are filtered out by means of a series of criteria, such as the area of the contours, the correlation coefficient between two regions of contours etc. Secondly, the cubic spline interpolation is adopted to process the central contour region of the CCT. The contours of the interpolated image are extracted again, then the least square ellipse fitting is performed to calculate the center coordinates of the CCT. Finally, the encoded value is obtained by the angle information from the circular encoding band of the CCT. From the experiment results, the location precision of the CCT can be achieved to sub-pixel level of the algorithm presented. Meanwhile the recognition accuracy is pretty high, even if the background of the image is complex and full of disturbances. In addition, the property of the algorithm is robust. Furthermore, the runtime of the algorithm is fast.

  17. Automated Point Cloud Correspondence Detection for Underwater Mapping Using AUVs

    NASA Technical Reports Server (NTRS)

    Hammond, Marcus; Clark, Ashley; Mahajan, Aditya; Sharma, Sumant; Rock, Stephen

    2015-01-01

    An algorithm for automating correspondence detection between point clouds composed of multibeam sonar data is presented. This allows accurate initialization for point cloud alignment techniques even in cases where accurate inertial navigation is not available, such as iceberg profiling or vehicles with low-grade inertial navigation systems. Techniques from computer vision literature are used to extract, label, and match keypoints between "pseudo-images" generated from these point clouds. Image matches are refined using RANSAC and information about the vehicle trajectory. The resulting correspondences can be used to initialize an iterative closest point (ICP) registration algorithm to estimate accumulated navigation error and aid in the creation of accurate, self-consistent maps. The results presented use multibeam sonar data obtained from multiple overlapping passes of an underwater canyon in Monterey Bay, California. Using strict matching criteria, the method detects 23 between-swath correspondence events in a set of 155 pseudo-images with zero false positives. Using less conservative matching criteria doubles the number of matches but introduces several false positive matches as well. Heuristics based on known vehicle trajectory information are used to eliminate these.

  18. Access control violation prevention by low-cost infrared detection

    NASA Astrophysics Data System (ADS)

    Rimmer, Andrew N.

    2004-09-01

    A low cost 16x16 un-cooled pyroelectric detector array, allied with advanced tracking and detection algorithms, has enabled the development of a universal detector with a wide range of applications in people monitoring and homeland security. Violation of access control systems, whether controlled by proximity card, biometrics, swipe card or similar, may occur by 'tailgating' or 'piggybacking' where an 'approved' entrant with a valid entry card is accompanied by a closely spaced 'non-approved' entrant. The violation may be under duress, where the accompanying person is attempting to enter a secure facility by force or threat. Alternatively, the violation may be benign where staff members collude either through habit or lassitude, either with each other or with third parties, without considering the security consequences. Examples of the latter could include schools, hospitals or maternity homes. The 16x16 pyroelectric array is integrated into a detector or imaging system which incorporates data processing, target extraction and decision making algorithms. The algorithms apply interpolation to the array output, allowing a higher level of resolution than might otherwise be expected from such a low resolution array. The pyroelectric detection principle means that the detection will work in variable light conditions and even in complete darkness, if required. The algorithms can monitor the shape, form, temperature and number of persons in the scene and utilise this information to determine whether a violation has occurred or not. As people are seen as 'hot blobs' and are not individually recognisable, civil liberties are not infringed in the detection process. The output from the detector is a simple alarm signal which may act as input to the access control system as an alert or to trigger CCTV image display and storage. The applications for a tailgate detector can be demonstrated across many medium security applications where there are no physical means to prevent this

  19. Network Detection in Raster Data Using Marked Point Processes

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Kruse, C.; Rottensteiner, F.; Soergel, U.; Heipke, C.

    2016-06-01

    We propose a new approach for the automatic detection of network structures in raster data. The model for the network structure is represented by a graph whose nodes and edges correspond to junction-points and to connecting line segments, respectively; nodes and edges are further described by certain parameters. We embed this model in the probabilistic framework of marked point processes and determine the most probable configuration of objects by stochastic sampling. That is, different graph configurations are constructed randomly by modifying the graph entity parameters, by adding and removing nodes and edges to/ from the current graph configuration. Each configuration is then evaluated based on the probabilities of the changes and an energy function describing the conformity with a predefined model. By using the Reversible Jump Markov Chain Monte Carlo sampler, a global optimum of the energy function is determined. We apply our method to the detection of river and tidal channel networks in digital terrain models. In comparison to our previous work, we introduce constraints concerning the flow direction of water into the energy function. Our goal is to analyse the influence of different parameter settings on the results of network detection in both, synthetic and real data. Our results show the general potential of our method for the detection of river networks in different types of terrain.

  20. Change point detection in risk adjusted control charts.

    PubMed

    Assareh, Hassan; Smith, Ian; Mengersen, Kerrie

    2015-12-01

    Precise identification of the time when a change in a clinical process has occurred enables experts to identify a potential special cause more effectively. In this article, we develop change point estimation methods for a clinical dichotomous process in the presence of case mix. We apply Bayesian hierarchical models to formulate the change point where there exists a step change in the odds ratio and logit of risk of a Bernoulli process. Markov Chain Monte Carlo is used to obtain posterior distributions of the change point parameters including location and magnitude of changes and also corresponding probabilistic intervals and inferences. The performance of the Bayesian estimator is investigated through simulations and the result shows that precise estimates can be obtained when they are used in conjunction with the risk-adjusted CUSUM and EWMA control charts. In comparison with alternative EWMA and CUSUM estimators, more accurate and precise estimates are obtained by the Bayesian estimator. These superiorities enhance when probability quantification, flexibility and generaliability of the Bayesian change point detection model are also considered. The Deviance Information Criterion, as a model selection criterion in the Bayesian context, is applied to find the best change point model for a given dataset where there is no prior knowledge about the change type in the process.

  1. Bisous model-Detecting filamentary patterns in point processes

    NASA Astrophysics Data System (ADS)

    Tempel, E.; Stoica, R. S.; Kipper, R.; Saar, E.

    2016-07-01

    The cosmic web is a highly complex geometrical pattern, with galaxy clusters at the intersection of filaments and filaments at the intersection of walls. Identifying and describing the filamentary network is not a trivial task due to the overwhelming complexity of the structure, its connectivity and the intrinsic hierarchical nature. To detect and quantify galactic filaments we use the Bisous model, which is a marked point process built to model multi-dimensional patterns. The Bisous filament finder works directly with the galaxy distribution data and the model intrinsically takes into account the connectivity of the filamentary network. The Bisous model generates the visit map (the probability to find a filament at a given point) together with the filament orientation field. Using these two fields, we can extract filament spines from the data. Together with this paper we publish the computer code for the Bisous model that is made available in GitHub. The Bisous filament finder has been successfully used in several cosmological applications and further development of the model will allow to detect the filamentary network also in photometric redshift surveys, using the full redshift posterior. We also want to encourage the astro-statistical community to use the model and to connect it with all other existing methods for filamentary pattern detection and characterisation.

  2. H2O frost point detection on Mars

    NASA Technical Reports Server (NTRS)

    Ryan, J. A.; Sharman, R. D.

    1981-01-01

    The Viking Mars landers contain meteorological instrumentation to measure wind, temperature, and pressure but not atmospheric water content. The landings occurred during local summer, and it was observed that the nocturnal temperature decrease at sensor height (1.6 m) did not exhibit a uniform behavior at either site. It was expected that the rate of decrease would gradually slow, leveling off near sunrise. Instead, a leveling occurred several hours earlier. Temperature subsequently began a more rapid decrease which slowed by sunrise. This suggested that the temperature sensors may be detecting the frost point of water vapor. Analysis of alternative hypotheses demonstrates that none of these are viable candidates. The frost point interpretation is consistent with other lander and orbiter observations, with terrestrial experience, and with modeling of Mars' atmospheric behavior. It thus appears that the meteorology experiment can help provide a basis toward understanding the distribution and dynamics of Martian water vapor.

  3. Fast, sensitive point of care electrochemical molecular system for point mutation and select agent detection.

    PubMed

    MacLeod, J A; Nemeth, A C; Dicke, W C; Wang, D; Manalili Wheeler, S; Hannis, J C; Collier, G B; Drader, J J

    2016-07-01

    Point of care molecular diagnostics benefits from a portable battery-operated device capable of performing a fast turnaround using reliable inexpensive cartridges. We describe a prototype device for performing a molecular diagnostics test for clinical and biodefense samples in 16 minutes using a prototype capable of an 8 minute PCR reaction, followed by hybridization and detection on an electrochemical microarray based on the i-STAT® system. We used human buccal swabs for hemochromatosis testing including in-device DNA extraction. Additional clinical and biodefense samples included influenza A and bacterial select agents Bacillus anthracis, Yersinia pestis and Francisella tularensis. PMID:27280174

  4. Utilizing Fission Technology to Enable Rapid and Affordable Access to any Point in the Solar System

    NASA Technical Reports Server (NTRS)

    Houts, Mike; Bonometti, Joe; Morton, Jeff; Hrbud, Ivana; Bitteker, Leo; VanDyke, Melissa; Godfroy, T.; Pedersen, K.; Dobson, C.; Patton, B.; Martin, J.; Chakrabarti, S.

    2000-01-01

    Fission technology can enable rapid, affordable access to any point in the solar system. Potential fission-based transportation options include bimodal nuclear thermal rockets, high specific energy propulsion systems, and pulsed fission propulsion systems. In-space propellant re-supply enhances the effective performance of all systems, but requires significant infrastructure development. Safe, timely, affordable utilization of first-generation space fission propulsion systems will enable the development of more advanced systems. First generation systems can build on over 45 years of US and international space fission system technology development to minimize cost.

  5. Improved efficiency access control equipment and explosive, weapons and drug abuse detection

    SciTech Connect

    Jenkins, A.; Milford, A.; Woollven, J.

    1985-01-01

    The second generation portal explosives detector has been designed with increased detection capability and convenience in service. The method of detection and performance relative to the first generation is described. A novel method of auto-calibration and self diagnosis is described and results are discussed. Improvements in convenience of operation have been achieved and operating space and costs reduced by combining metal detection capability, together with explosives detection. This allows both alarm signal and diagnostic outputs to be combined on a single remote panel in the guard room, and reduces the number of guards needed to man the access control. This type of access control is entirely a defensive measure against attack but a further additional feature is proposed which will also check the state of mind of all personnel passing through the check point. Any person suffering from the effect of narcotic or alcohol will be detected by their inability to reproduce their normal signature. A new method of signature analysis in five dimensions is described together with proposals for integrating the check without increasing the time in the test area. Some recent results on the effects of alcohol on signature reproduction is given.

  6. e-VLBI Access Point (eAXP) - a centralized control and EGAE configuration / management application

    NASA Astrophysics Data System (ADS)

    Ruszczyk, Chester Whitney, Alan

    Setting up experiments to utilize Experiment Guided Adaptive Endpoint (EGAE) and e-VLBI is presently a complex and time intensive process requiring scientific, Mark5 and networking knowledge. There is no central access to point to configure and manage all of these aspects of an experiment. The e-VLBI Access Point (eAXP) is a centralized control plane management tool that offers a GUI interface to augment the command line interface presently being used to set up and conduct experiments. eAXP contains three major toolsets: one to set up and execute an experiment using real-time or non-real time modes; the second to configure and manage EGAE; and a third to view statistics of the experiments. Initially the overall system architecture for eAXP is presented, followed by details of the Experiment Profiler toolset including screen shots of the system presently being tested. This will be followed by how eAXP will support real-time modes interfacing to the Dynamic Resource Allocation over GMPLS Optical Network (DRAGON) resource management project.

  7. Detection of Majorana Kramers pairs using a quantum point contact

    NASA Astrophysics Data System (ADS)

    Li, Jian; Pan, Wei; Bernevig, B. Andrei; Lutchyn, Roman

    We propose a setup that integrates a quantum point contact (QPC) and a Josephson junction on a quantum spin Hall sample, experimentally realizable in InAs/GaSb quantum wells. The confinement due to both the QPC and the superconductor results in a Kramers pair of Majorana zero-energy bound states when the superconducting phases in the two arms differ by an odd multiple of π across the Josephson junction. We investigate the detection of these Majorana pairs with the integrated QPC, and find a robust switching from normal to Andreev scattering across the edges due to the presence of Majorana Kramers pairs. This transport signature is expected to be exhibited in measurements of differential conductance and/or current cross-correlation at low bias. This work was supported by ONR-N00014-14-1-0330.

  8. Trend Estimation and Change Point Detection in Climatic Series

    NASA Astrophysics Data System (ADS)

    Bates, B. C.; Chandler, R. E.

    2011-12-01

    The problems of trend estimation and change point detection in climatic series have received substantial attention in recent years. Key issues include the magnitudes and directions of underlying trends, and the existence (or otherwise) of abrupt shifts in the mean background state. There are many procedures in use including: t-tests, Mann-Whitney and Pettit tests, linear and piecewise linear regression; cumulative sum analysis; hierarchical Bayesian change point analysis; Markov chain Monte Carlo methods; and reversible jump Markov chain Monte Carlo. The purpose of our presentation is to motivate wider use of modern regression techniques for trend estimation and change point detection in climatic series. We pay particular attention to the underlying statistical assumptions as their violation can lead to serious errors in data interpretation and study conclusions. In this context we consider two case studies. The first involves the application of local linear regression and a test for discontinuities in the regression function to the winter (December-March) North Atlantic Oscillation (NAO) index series for the period 1864-2010. This series exhibits a reversal from strongly negative values in the late 1960s to strongly positive NAO index values in the mid-1990s. The second involves the analysis of a seasonal (June to October) series of typhoon counts in the vicinity of Taiwan for the period 1970-2006. A previous investigation by other researchers concluded that an abrupt shift in this series occurred between 1999 and 2000. For both case studies, our findings indicate little evidence for abrupt shifts: rather, the decadal to multidecadal changes in the mean levels of both series appear well described by smooth trends. For the winter NAO index series, the trend is non-monotonic; for the typhoon counts, it can be regarded as linear on the square root scale. Our statistical results do not contradict those obtained by other researchers: our interpretation of these results

  9. Detecting Inappropriate Access to Electronic Health Records Using Collaborative Filtering

    PubMed Central

    Menon, Aditya Krishna; Jiang, Xiaoqian; Kim, Jihoon; Vaidya, Jaideep; Ohno-Machado, Lucila

    2013-01-01

    Many healthcare facilities enforce security on their electronic health records (EHRs) through a corrective mechanism: some staff nominally have almost unrestricted access to the records, but there is a strict ex post facto audit process for inappropriate accesses, i.e., accesses that violate the facility’s security and privacy policies. This process is inefficient, as each suspicious access has to be reviewed by a security expert, and is purely retrospective, as it occurs after damage may have been incurred. This motivates automated approaches based on machine learning using historical data. Previous attempts at such a system have successfully applied supervised learning models to this end, such as SVMs and logistic regression. While providing benefits over manual auditing, these approaches ignore the identity of the users and patients involved in a record access. Therefore, they cannot exploit the fact that a patient whose record was previously involved in a violation has an increased risk of being involved in a future violation. Motivated by this, in this paper, we propose a collaborative filtering inspired approach to predicting inappropriate accesses. Our solution integrates both explicit and latent features for staff and patients, the latter acting as a personalized “finger-print” based on historical access patterns. The proposed method, when applied to real EHR access data from two tertiary hospitals and a file-access dataset from Amazon, shows not only significantly improved performance compared to existing methods, but also provides insights as to what indicates an inappropriate access. PMID:24683293

  10. Building secure wireless access point based on certificate authentication and firewall captive portal

    NASA Astrophysics Data System (ADS)

    Soewito, B.; Hirzi

    2014-03-01

    Wireless local area network or WLAN more vulnerability than wired network even though WLAN has many advantages over wired. Wireless networks use radio transmissions to carry data between end users and access point. Therefore, it is possible for someone to sit in your office building's lobby or parking lot or parking lot to eavesdrop on the wireless network communication. This paper discussed securing wires local area network used WPA2 Enterprise based PEAP MS-CHAP and Captive portal firewall. We also divided the network for employer and visitor to increase the level of security. Our experiment showed that the WLAN could be broken using the attacker tool such as airodump, aireply, and aircrack.

  11. Autonomous detection of text fade point with color laser printers

    NASA Astrophysics Data System (ADS)

    Ju, Yanling; Maggard, Eric; Jessome, Renee; Allebach, Jan

    2015-01-01

    Fading is one of the issues of most critical concern for print quality degradation with color laser electro- photographic printers. Fading occurs when the cartridge is depleted. ISO/IEC 19798:2007(E) specifies a process for determining the cartridge page yield for a given color electro-photographic printer model. It is based on repeatedly printing a suite of test pages, followed by visual examination of the sequence of printed diagnostic pages. But this method is a very costly process since it involves visual examination of a large number of pages. And also the final decision is based on the visual examination of a specially designed diagnostic page, which is different than typical office document pages, since it consists of color bars, and contains no text. In this paper, we propose a new method to autonomously detect the text fading in prints from home or office color printers using a typical office document page instead of a specially designed diagnostic page. In our method, we scan and analyze the printed pages to predict where expert observers would judge fading to have occurred in the print sequence. Our approach is based on a machine-learning framework in which features derived from image analysis are mapped to a fade point prediction.

  12. Detection of Majorana Kramers Pairs Using a Quantum Point Contact.

    PubMed

    Li, Jian; Pan, Wei; Bernevig, B Andrei; Lutchyn, Roman M

    2016-07-22

    We propose a setup that integrates a quantum point contact (QPC) and a Josephson junction on a quantum spin Hall sample, experimentally realizable in InAs/GaSb quantum wells. The confinement due to both the QPC and the superconductor results in a Kramers pair of Majorana zero-energy bound states when the superconducting phases in the two arms differ by an odd multiple of π across the Josephson junction. We investigate the detection of these Majorana pairs with the integrated QPC, and find a robust switching from normal to Andreev scattering across the edges due to the presence of Majorana Kramers pairs. Such a switching of the current represents a qualitative signature where multiterminal differential conductances oscillate with alternating signs when the external magnetic field is tuned. We show that this qualitative signature is also present in current cross-correlations. Thus, the change of the backscattering current nature affects both conductance and shot noise, the measurement of which offers a significant advantage over quantitative signatures such as conductance quantization in realistic measurements. PMID:27494493

  13. Detection of Majorana Kramers Pairs Using a Quantum Point Contact

    NASA Astrophysics Data System (ADS)

    Li, Jian; Pan, Wei; Bernevig, B. Andrei; Lutchyn, Roman M.

    2016-07-01

    We propose a setup that integrates a quantum point contact (QPC) and a Josephson junction on a quantum spin Hall sample, experimentally realizable in InAs/GaSb quantum wells. The confinement due to both the QPC and the superconductor results in a Kramers pair of Majorana zero-energy bound states when the superconducting phases in the two arms differ by an odd multiple of π across the Josephson junction. We investigate the detection of these Majorana pairs with the integrated QPC, and find a robust switching from normal to Andreev scattering across the edges due to the presence of Majorana Kramers pairs. Such a switching of the current represents a qualitative signature where multiterminal differential conductances oscillate with alternating signs when the external magnetic field is tuned. We show that this qualitative signature is also present in current cross-correlations. Thus, the change of the backscattering current nature affects both conductance and shot noise, the measurement of which offers a significant advantage over quantitative signatures such as conductance quantization in realistic measurements.

  14. Performance analysis of commercial multiple-input-multiple-output access point in distributed antenna system.

    PubMed

    Fan, Yuting; Aighobahi, Anthony E; Gomes, Nathan J; Xu, Kun; Li, Jianqiang

    2015-03-23

    In this paper, we experimentally investigate the throughput of IEEE 802.11n 2x2 multiple-input-multiple-output (MIMO) signals in a radio-over-fiber-based distributed antenna system (DAS) with different fiber lengths and power imbalance. Both a MIMO-supported access point (AP) and a spatial-diversity-supported AP were separately employed in the experiments. Throughput measurements were carried out with wireless users at different locations in a typical office environment. For the different fiber length effect, the results indicate that MIMO signals can maintain high throughput when the fiber length difference between the two remote antenna units (RAUs) is under 100 m and falls quickly when the length difference is greater. For the spatial diversity signals, high throughput can be maintained even when the difference is 150 m. On the other hand, the separation of the MIMO antennas allows additional freedom in placing the antennas in strategic locations for overall improved system performance, although it may also lead to received power imbalance problems. The results show that the throughput performance drops in specific positions when the received power imbalance is above around 13 dB. Hence, there is a trade-off between the extent of the wireless coverage for moderate bit-rates and the area over which peak bit-rates can be achieved. PMID:25837089

  15. Centrality measures highlight proton traps and access points to proton highways in kinetic Monte Carlo trajectories

    SciTech Connect

    Krueger, Rachel A.; Haibach, Frederick G.; Fry, Dana L.; Gomez, Maria A.

    2015-04-21

    A centrality measure based on the time of first returns rather than the number of steps is developed and applied to finding proton traps and access points to proton highways in the doped perovskite oxides: AZr{sub 0.875}D{sub 0.125}O{sub 3}, where A is Ba or Sr and the dopant D is Y or Al. The high centrality region near the dopant is wider in the SrZrO{sub 3} systems than the BaZrO{sub 3} systems. In the aluminum-doped systems, a region of intermediate centrality (secondary region) is found in a plane away from the dopant. Kinetic Monte Carlo (kMC) trajectories show that this secondary region is an entry to fast conduction planes in the aluminum-doped systems in contrast to the highest centrality area near the dopant trap. The yttrium-doped systems do not show this secondary region because the fast conduction routes are in the same plane as the dopant and hence already in the high centrality trapped area. This centrality measure complements kMC by highlighting key areas in trajectories. The limiting activation barriers found via kMC are in very good agreement with experiments and related to the barriers to escape dopant traps.

  16. Performance analysis of commercial multiple-input-multiple-output access point in distributed antenna system.

    PubMed

    Fan, Yuting; Aighobahi, Anthony E; Gomes, Nathan J; Xu, Kun; Li, Jianqiang

    2015-03-23

    In this paper, we experimentally investigate the throughput of IEEE 802.11n 2x2 multiple-input-multiple-output (MIMO) signals in a radio-over-fiber-based distributed antenna system (DAS) with different fiber lengths and power imbalance. Both a MIMO-supported access point (AP) and a spatial-diversity-supported AP were separately employed in the experiments. Throughput measurements were carried out with wireless users at different locations in a typical office environment. For the different fiber length effect, the results indicate that MIMO signals can maintain high throughput when the fiber length difference between the two remote antenna units (RAUs) is under 100 m and falls quickly when the length difference is greater. For the spatial diversity signals, high throughput can be maintained even when the difference is 150 m. On the other hand, the separation of the MIMO antennas allows additional freedom in placing the antennas in strategic locations for overall improved system performance, although it may also lead to received power imbalance problems. The results show that the throughput performance drops in specific positions when the received power imbalance is above around 13 dB. Hence, there is a trade-off between the extent of the wireless coverage for moderate bit-rates and the area over which peak bit-rates can be achieved.

  17. ICSW2AN : An Inter-vehicle Communication System Using Mobile Access Point over Wireless Wide Area Networks

    NASA Astrophysics Data System (ADS)

    Byun, Tae-Young

    This paper presents a prototype of inter-vehicle communication system using mobile access point that internetworks wired or wireless LAN and wireless WAN anywhere. Implemented mobile access point can be equipped with various wireless WAN interfaces such as WCDMA and HSDPA. Mobile access point in the IP mechanism has to process connection setup procedure to one wireless WAN. To show the applicability of the mobile access point to inter-vehicle communication, a simplified V2I2V-based car communication system called ICSW2AN is implemented to evaluate major performance metrics by road test. In addition, results of road test for traffic information service are investigated in view of RTT, latency and server processing time. The experimental result indicates that V2I2V-based car communication system sufficiently can provide time-tolerant traffic information to moving vehicles while more than two mobile devices in restricted spaces such as car, train and ship access wireless Internet simultaneously.

  18. A Point to Share: Streamlining Access Services Workflow through Online Collaboration, Communication, and Storage with Microsoft SharePoint

    ERIC Educational Resources Information Center

    Diffin, Jennifer; Chirombo, Fanuel; Nangle, Dennis; de Jong, Mark

    2010-01-01

    This article explains how the document management team (circulation and interlibrary loan) at the University of Maryland University College implemented Microsoft's SharePoint product to create a central hub for online collaboration, communication, and storage. Enhancing the team's efficiency, organization, and cooperation was the primary goal.…

  19. The Water Quality Portal: a single point of access for water quality data

    NASA Astrophysics Data System (ADS)

    Kreft, J.

    2015-12-01

    The Water Quality Portal (WQP) is a cooperative project between the U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (EPA) overseen by the National Water Quality Monitoring Council (NWQMC). It was launched in April of 2012 as a single point of access for discrete water quality samples stored in the USGS NWIS and EPA STORET systems. Since launch thousands of users have visited the Water Quality Portal to download billions of results that are pertinent to their interests. Numerous tools have also been developed that use WQP web services as a source of data for further analysis. Since the launch of the Portal, the WQP development team at the USGS Center for Integrated Data Analytics has worked with USGS and EPA stakeholders as well as the wider user community to add significant new features to the WQP. WQP users can now directly plot sites of interest on a web map based on any of the 164 WQP query parameters, and then download data of interest directly from that map. In addition, the WQP has expanded beyond just serving out NWIS and STORET data, and provides data from the US Department of Agriculture's Agricultural Research Service STEWARDS system, the USGS BioData system and is working with others to bring in additional data. Finally, the WQP is linked to another NWQMC-supported project, the National Environmental Methods Index (NEMI), so WQP users can easily find the method behind the data that they are using. Future work is focused on incorporating additional biological data from the USGS BioData system, broadening the scope of discrete water quality sample types from STORET, and developing approaches to make the data in the WQP more visible and usable. The WQP team is also exploring ways to further integrate with other systems, such as those operated the U.S. Department of Agriculture Forest Service and other federal agencies to facilitate the overarching goal of improving access to water quality data for all users.

  20. Nonparametric decomposition of quasi-periodic time series for change-point detection

    NASA Astrophysics Data System (ADS)

    Artemov, Alexey; Burnaev, Evgeny; Lokot, Andrey

    2015-12-01

    The paper is concerned with the sequential online change-point detection problem for a dynamical system driven by a quasiperiodic stochastic process. We propose a multicomponent time series model and an effective online decomposition algorithm to approximate the components of the models. Assuming the stationarity of the obtained components, we approach the change-point detection problem on a per-component basis and propose two online change-point detection schemes corresponding to two real-world scenarios. Experimental results for decomposition and detection algorithms for synthesized and real-world datasets are provided to demonstrate the efficiency of our change-point detection framework.

  1. Effects of Point-Loss Punishers on Human Signal-Detection Performance

    ERIC Educational Resources Information Center

    Lie, Celia; Alsop, Brent

    2009-01-01

    Three experiments using human participants varied the distribution of point-gain reinforcers or point-loss punishers in two-alternative signal-detection procedures. Experiment 1 varied the distribution of point-gain reinforcers for correct responses (Group A) and point-loss punishers for errors (Group B) across conditions. Response bias varied…

  2. Human detection and motion analysis at security points

    NASA Astrophysics Data System (ADS)

    Ozer, I. Burak; Lv, Tiehan; Wolf, Wayne H.

    2003-08-01

    This paper presents a real-time video surveillance system for the recognition of specific human activities. Specifically, the proposed automatic motion analysis is used as an on-line alarm system to detect abnormal situations in a campus environment. A smart multi-camera system developed at Princeton University is extended for use in smart environments in which the camera detects the presence of multiple persons as well as their gestures and their interaction in real-time.

  3. Can Detectability Analysis Improve the Utility of Point Counts for Temperate Forest Raptors?

    EPA Science Inventory

    Temperate forest breeding raptors are poorly represented in typical point count surveys because these birds are cryptic and typically breed at low densities. In recent years, many new methods for estimating detectability during point counts have been developed, including distanc...

  4. An Experimental Performance Measurement of Implemented Wireless Access Point for Interworking Wi-Fi and HSDPA Networks

    NASA Astrophysics Data System (ADS)

    Byun, Tae-Young

    This paper presents a prototype of WAP(Wireless Access Point) that provides the wireless Internet access anywhere. Implemented WAP can be equipped with various wireless WAN interfaces such as WCDMA and HSDPA. WAP in the IP mechanism has to process connection setup procedure to one wireless WAN. Also, WAP can provide connection management procedures to reconnect interrupted connection automatically. By using WAP, several mobile devices such as netbook, UMPC and smart-phone in a moving vehicle can access to HSDPA network simultaneously. So, it has more convenient for using the WAP when there are needs to access wireless Internet more than two mobile devices in restricted spaces such as car, train and ship.

  5. Effects of sampling strategy, detection probability, and independence of counts on the use of point counts

    USGS Publications Warehouse

    Pendleton, G.W.; Ralph, C. John; Sauer, John R.; Droege, Sam

    1995-01-01

    Many factors affect the use of point counts for monitoring bird populations, including sampling strategies, variation in detection rates, and independence of sample points. The most commonly used sampling plans are stratified sampling, cluster sampling, and systematic sampling. Each of these might be most useful for different objectives or field situations. Variation in detection probabilities and lack of independence among sample points can bias estimates and measures of precision. All of these factors should be con-sidered when using point count methods.

  6. The D-FCM partitioned D-BSP tree for massive point cloud data access and rendering

    NASA Astrophysics Data System (ADS)

    Zhang, Yi

    2016-10-01

    The spatial partitioning of massive point cloud data involves dividing the space into a multi-tree structure step by step, so as to achieve the purpose of fast access and to render the point cloud. The current methods are based on spatial regularity and equal division, which is not consistent with the irregular and non-uniform distribution of most point clouds. This paper presents a directional fuzzy c-means (D-FCM) method for irregular spatial partitioning. The distance metric is weighted by a direction coefficient, which is determined by the eigenvalue of the point cloud. The orientation of each node is adaptively calculated by principal component analysis of the point cloud, and Karhunen-Loeve (KL) transform is applied to the points coordinates in node. A binary space partitioning (BSP) tree structure is used to partition the point cloud data node by node, and a directional BSP (D-BSP) tree is formed. The D-BSP tree structure was tested with point clouds of 0.1 million to over 2 billion points (up to 60 GB). The experimental results showed that the D-BSP tree can ensure that the bounding boxes are close to the actual spatial distribution of the point cloud, it can completely expand along the spatial configuration of the point cloud without generating unnecessary partitioning, and it can achieve a higher rendering speed with less memory requirement.

  7. Autonomous Onboard Point Source Detection by Small Exploration Spacecraft

    NASA Astrophysics Data System (ADS)

    Huffman, W.; Thompson, D. R.; Bue, B.; Castillo-Rogez, J.; Boland, J.

    2015-12-01

    Small spacecraft platforms are a promising low-cost approach to accelerate exploration of small bodies, addressing the space community's interest in origin science, planetary resources, and planetary defense. However, they can be challenging platforms for detecting and imaging low brightness targets. Difficulties include constrained bandwidth, which limits the volume of data that can be downlinked; attitude instability, which limits exposure time; small instrument apertures, which reduce sensitivity; and cosmic ray contamination, which creates illusory sources. Mission designers can address all these problems simultaneously by shifting image analysis across the communications gap. Spacecraft can use onboard data analysis to detect sources directly, or downlink parsimonious summary products for detection on the ground. One promising approach is to acquire stacks of short consecutive exposures, and then coregister and coadd them onboard. This work analyzes a coaddition algorithm that is designed to be robust against small spacecraft challenges. We evaluate factors affecting performance, such as attitude control and camera noise systematics, in regimes typical of small spacecraft missions. We motivate the algorithm design by considering its application to NEAScout, a mission representing a new generation of small (sub-50 kg) exploration spacecraft having very small instrument apertures and data rates below 1 kbyte s-1. Here, onboard analysis allows detection and rendezvous with far smaller and fainter objects, dramatically reducing the cost and complexity of primitive bodies exploration.

  8. Proximal and point detection of contaminated surfaces using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason A.; Christesen, Steven D.; Tripathi, Ashish; Emmons, Erik D.; Wilcox, Phillip G.; Emge, Darren K.; Pardoe, Ian J.; Fountain, Augustus W., III

    2011-11-01

    We are actively investigating the use of Raman spectroscopy for proximal standoff detection of chemicals and explosive materials on surfaces. These studies include Raman Chemical Imaging of contaminated fingerprints for forensic attribution and the assessments of commercial handheld or portable Raman instruments operating with near-infrared (IR) as well as ultraviolet (UV) laser excitation specifically developed for on-the-move reconnaissance of chemical contamination. As part of these efforts, we have measured the Raman cross sections of chemical agents, toxic industrial chemicals, and explosives from the UV to NIR. We have also measured and modeled the effect interrogation angle has on the Raman return from droplets on man-made surfaces. Realistic droplet distributions have been modeled and tested against variations in surface scan patterns and laser spot size for determining the optimum scan characteristics for detection of relevant surface contamination.

  9. Electricity-free amplification and detection for molecular point-of-care diagnosis of HIV-1.

    PubMed

    Singleton, Jered; Osborn, Jennifer L; Lillis, Lorraine; Hawkins, Kenneth; Guelig, Dylan; Price, Will; Johns, Rachel; Ebels, Kelly; Boyle, David; Weigl, Bernhard; LaBarre, Paul

    2014-01-01

    In resource-limited settings, the lack of decentralized molecular diagnostic testing and sparse access to centralized medical facilities can present a critical barrier to timely diagnosis, treatment, and subsequent control and elimination of infectious diseases. Isothermal nucleic acid amplification methods, including reverse transcription loop-mediated isothermal amplification (RT-LAMP), are well-suited for decentralized point-of-care molecular testing in minimal infrastructure laboratories since they significantly reduce the complexity of equipment and power requirements. Despite reduced complexity, however, there is still a need for a constant heat source to enable isothermal nucleic acid amplification. This requirement poses significant challenges for laboratories in developing countries where electricity is often unreliable or unavailable. To address this need, we previously developed a low-cost, electricity-free heater using an exothermic reaction thermally coupled with a phase change material. This heater achieved acceptable performance, but exhibited considerable variability. Furthermore, as an enabling technology, the heater was an incomplete diagnostic solution. Here we describe a more precise, affordable, and robust heater design with thermal standard deviation <0.5°C at operating temperature, a cost of approximately US$.06 per test for heater reaction materials, and an ambient temperature operating range from 16°C to 30°C. We also pair the heater with nucleic acid lateral flow (NALF)-detection for a visual readout. To further illustrate the utility of the electricity-free heater and NALF-detection platform, we demonstrate sensitive and repeatable detection of HIV-1 with a ß-actin positive internal amplification control from processed sample to result in less than 80 minutes. Together, these elements are building blocks for an electricity-free platform capable of isothermal amplification and detection of a variety of pathogens.

  10. Electricity-Free Amplification and Detection for Molecular Point-of-Care Diagnosis of HIV-1

    PubMed Central

    Singleton, Jered; Osborn, Jennifer L.; Lillis, Lorraine; Hawkins, Kenneth; Guelig, Dylan; Price, Will; Johns, Rachel; Ebels, Kelly; Boyle, David; Weigl, Bernhard; LaBarre, Paul

    2014-01-01

    In resource-limited settings, the lack of decentralized molecular diagnostic testing and sparse access to centralized medical facilities can present a critical barrier to timely diagnosis, treatment, and subsequent control and elimination of infectious diseases. Isothermal nucleic acid amplification methods, including reverse transcription loop-mediated isothermal amplification (RT-LAMP), are well-suited for decentralized point-of-care molecular testing in minimal infrastructure laboratories since they significantly reduce the complexity of equipment and power requirements. Despite reduced complexity, however, there is still a need for a constant heat source to enable isothermal nucleic acid amplification. This requirement poses significant challenges for laboratories in developing countries where electricity is often unreliable or unavailable. To address this need, we previously developed a low-cost, electricity-free heater using an exothermic reaction thermally coupled with a phase change material. This heater achieved acceptable performance, but exhibited considerable variability. Furthermore, as an enabling technology, the heater was an incomplete diagnostic solution. Here we describe a more precise, affordable, and robust heater design with thermal standard deviation <0.5°C at operating temperature, a cost of approximately US$.06 per test for heater reaction materials, and an ambient temperature operating range from 16°C to 30°C. We also pair the heater with nucleic acid lateral flow (NALF)-detection for a visual readout. To further illustrate the utility of the electricity-free heater and NALF-detection platform, we demonstrate sensitive and repeatable detection of HIV-1 with a ß-actin positive internal amplification control from processed sample to result in less than 80 minutes. Together, these elements are building blocks for an electricity-free platform capable of isothermal amplification and detection of a variety of pathogens. PMID:25426953

  11. Apollo: Giving application developers a single point of access to public health models using structured vocabularies and Web services

    PubMed Central

    Wagner, Michael M.; Levander, John D.; Brown, Shawn; Hogan, William R.; Millett, Nicholas; Hanna, Josh

    2013-01-01

    This paper describes the Apollo Web Services and Apollo-SV, its related ontology. The Apollo Web Services give an end-user application a single point of access to multiple epidemic simulators. An end user can specify an analytic problem—which we define as a configuration and a query of results—exactly once and submit it to multiple epidemic simulators. The end user represents the analytic problem using a standard syntax and vocabulary, not the native languages of the simulators. We have demonstrated the feasibility of this design by implementing a set of Apollo services that provide access to two epidemic simulators and two visualizer services. PMID:24551417

  12. Single-molecule sequence detection via microfluidic planar extensional flow at a stagnation point

    PubMed Central

    Dylla-Spears, Rebecca; Townsend, Jacqueline E.; Jen-Jacobson, Linda; Sohn, Lydia L.; Muller, Susan J.

    2012-01-01

    We demonstrate the use of a microfluidic stagnation point flow to trap and extend single molecules of double-stranded (ds) genomic DNA for detection of target sequences along the DNA backbone. Mutant EcoRI-based fluorescent markers are bound sequence-specifically to fluorescently labeled ds λ-DNA. The marker-DNA complexes are introduced into a microfluidic cross slot consisting of flow channels that intersect at ninety degrees. Buffered solution containing the marker-DNA complexes flows in one channel of the cross slot, pure buffer flows in the opposing channel at the same flow rate, and fluid exits the two channels at ninety degrees from the inlet channels. This creates a stagnation point at the center of a planar extensional flow, where marker-DNA complexes may be trapped and elongated along the outflow axis. The degree of elongation can be controlled using the flow strength (i.e., a non-dimensional flow rate) in the device. Both the DNA backbone and the markers bound along the stretched DNA are observed directly using fluorescence microscopy and the location of the markers along the DNA backbone is measured. We find that our method permits detection of each of the five expected target site positions to within 1.5 kb with standard deviations of <1.5 kb. We compare the method’s precision and accuracy at molecular extensions of 68% and 88% of the contour length to binding distributions from similar data obtained via molecular combing. We also provide evidence that increased mixing of the sample during binding of the marker to the DNA improves binding to internal target sequences of dsDNA, presumably by extending the DNA and making the internal binding sites more accessible. PMID:20358051

  13. Detecting switching points using asymmetric detrended fluctuation analysis

    NASA Astrophysics Data System (ADS)

    Rivera-Castro, Miguel A.; Miranda, José G. V.; Cajueiro, Daniel O.; Andrade, Roberto F. S.

    2012-01-01

    This work uses the concept of Asymmetric Detrended Fluctuation Analysis (A-DFA) to investigate and characterize the occurrence of trend switching in financial series. A-DFA introduces two new roughness exponents, H+ and H-, which differ from the usual one H by separately taking into account contributions to the fluctuations according to whether the local trend is, respectively, upward or downward. The developed methodology requires the evaluation of local values of H(t),H+(t), and H-(t), by restricting the size of the largest window around the value t. We show that H+(t) and H-(t) behave differently in the neighborhoods of switching points (SPs) where trends change sign. Properly taken differences between shifted local values of H(t),H+(t), and H-(t) allow to identify and characterize SP's. Tests with Weiertrasse functions, isolated peaks, and actual financial series are presented, supporting the validity of the proposed method.

  14. Considerations on private human access to space from an institutional point of view

    NASA Astrophysics Data System (ADS)

    Hufenbach, Bernhard

    2013-12-01

    Private human access to space as discussed in this article addresses two market segments: suborbital flight and crew flights to Low Earth Orbit. The role of entrepreneurs, the technical complexity, the customers, the market conditions as well as the time to market in these two segments differ significantly. Space agencies take currently a very different approach towards private human access to space in both segments. Analysing the outcome of broader inter-agency deliberations on the future of human spaceflight and exploration, performed e.g. in the framework of the International Space Exploration Coordination Group, enables to derive some common general views on this topic. Various documents developed by inter-agency working groups recognise the general strategic importance for enabling private human access to space for ensuring a sustainable future of human spaceflight, although the specific definition of private human access and approaches vary. ESA has performed some reflections on this subject throughout the last 5 years. While it gained through these reflections a good understanding on the opportunities and implications resulting from the development of capabilities and markets for Private Human Access, limited concrete activities have been initiated in relation to this topic as of today.

  15. Point pattern match-based change detection in a constellation of previously detected objects

    DOEpatents

    Paglieroni, David W.

    2016-06-07

    A method and system is provided that applies attribute- and topology-based change detection to objects that were detected on previous scans of a medium. The attributes capture properties or characteristics of the previously detected objects, such as location, time of detection, detection strength, size, elongation, orientation, etc. The locations define a three-dimensional network topology forming a constellation of previously detected objects. The change detection system stores attributes of the previously detected objects in a constellation database. The change detection system detects changes by comparing the attributes and topological consistency of newly detected objects encountered during a new scan of the medium to previously detected objects in the constellation database. The change detection system may receive the attributes of the newly detected objects as the objects are detected by an object detection system in real time.

  16. Autonomous detection of ISO fade point with color laser printers

    NASA Astrophysics Data System (ADS)

    Yan, Ni; Maggard, Eric; Fothergill, Roberta; Jessome, Renee J.; Allebach, Jan P.

    2015-01-01

    Image quality assessment is a very important field in image processing. Human observation is slow and subjective, it also requires strict environment setup for the psychological test 1. Thus developing algorithms to match desired human experiments is always in need. Many studies have focused on detecting the fading phenomenon after the materials are printed, that is to monitor the persistence of the color ink 2-4. However, fading is also a common artifact produced by printing systems when the cartridges run low. We want to develop an automatic system to monitor cartridge life and report fading defects when they appear. In this paper, we first describe a psychological experiment that studies the human perspective on printed fading pages. Then we propose an algorithm based on Color Space Projection and K-means clustering to predict the visibility of fading defects. At last, we integrate the psychological experiment result with our algorithm to give a machine learning tool that monitors cartridge life.

  17. Detection of Slope Movement by Comparing Point Clouds Created by SFM Software

    NASA Astrophysics Data System (ADS)

    Oda, Kazuo; Hattori, Satoko; Takayama, Toko

    2016-06-01

    This paper proposes movement detection method between point clouds created by SFM software, without setting any onsite georeferenced points. SfM software, like Smart3DCaputure, PhotoScan, and Pix4D, are convenient for non-professional operator of photogrammetry, because these systems require simply specification of sequence of photos and output point clouds with colour index which corresponds to the colour of original image pixel where the point is projected. SfM software can execute aerial triangulation and create dense point clouds fully automatically. This is useful when monitoring motion of unstable slopes, or loos rocks in slopes along roads or railroads. Most of existing method, however, uses mesh-based DSM for comparing point clouds before/after movement and it cannot be applied in such cases that part of slopes forms overhangs. And in some cases movement is smaller than precision of ground control points and registering two point clouds with GCP is not appropriate. Change detection method in this paper adopts CCICP (Classification and Combined ICP) algorithm for registering point clouds before / after movement. The CCICP algorithm is a type of ICP (Iterative Closest Points) which minimizes point-to-plane, and point-to-point distances, simultaneously, and also reject incorrect correspondences based on point classification by PCA (Principle Component Analysis). Precision test shows that CCICP method can register two point clouds up to the 1 pixel size order in original images. Ground control points set in site are useful for initial setting of two point clouds. If there are no GCPs in site of slopes, initial setting is achieved by measuring feature points as ground control points in the point clouds before movement, and creating point clouds after movement with these ground control points. When the motion is rigid transformation, in case that a loose Rock is moving in slope, motion including rotation can be analysed by executing CCICP for a loose rock and

  18. DETECTING THE GAZING ATTENTION POINTS OF YOUNG AND ELDERLY CYCLISTS.

    PubMed

    Uetake, Teruo; Shimoda, Masahiro

    2014-06-01

    This study analyzed the perceived attention represented by "gazing" points of cyclists to expose a latent accidental factor hidden in cyclist behaviour. Eleven elderly people and 23 young people equipped with an eye camera participated in the study. From the camera images, the objects viewed by the cyclists were analyzed. A main road and a community road were used in the experiment. The objects viewed by the cyclists were categorized into nine items that would be indirectly related to the cause of bicycle traffic accidents: gates and porches, parking lots, signals, alleys, other bicycles on the road, pedestrians, signs and painted symbols on the road, schoolyards and houses, and other items. The results of the study indicated that many elderly cyclists always confirmed their safety at alley intersections along both main and community roads, whereas many young people were not so dutiful. The results for unsafe gazing behavior such as looking at a schoolyard or house while cycling were the same for the two groups in that most individuals did not look away from the road while cycling along the main and community roads. Dissimilar results, especially those for alley intersections, resulted from young people not paying due attention to objects, suggesting that such gazing behaviour could be strongly related to traffic accidents involving a bicycle. PMID:26182670

  19. Infrared moving point target detection based on spatial-temporal local contrast filter

    NASA Astrophysics Data System (ADS)

    Deng, Lizhen; Zhu, Hu; Tao, Chao; Wei, Yantao

    2016-05-01

    Infrared moving point target detection is a challenging task. In this paper, we define a novel spatial local contrast (SLC) and a novel temporal local contrast (TLC) to enhance the target's contrast. Based on the defined spatial local contrast and temporal local contrast, we propose a simple but powerful spatial-temporal local contrast filter (STLCF) to detect moving point target from infrared image sequences. In order to verify the performance of spatial-temporal local contrast filter on detecting moving point target, different detection methods are used to detect the target from several infrared image sequences for comparison. The experimental results show that the proposed spatial-temporal local contrast filter has great superiority in moving point target detection.

  20. Increment of Access Points in Integrated System of Wavelength Division Multiplexed Passive Optical Network Radio over Fiber.

    PubMed

    Amiri, I S; Alavi, S E; Soltanian, M R K; Fisal, N; Supa'at, A S M; Ahmad, H

    2015-01-01

    This paper describes a novel technique to increase the numbers of access points (APs) in a wavelength division multiplexed-passive optical network (WDM-PON) integrated in a 100 GHz radio-over-fiber (RoF). Eight multi-carriers separated by 25 GHz intervals were generated in the range of 193.025 to 193.200 THz using a microring resonator (MRR) system incorporating an add-drop filter system. All optically generated multi-carriers were utilized in an integrated system of WDM-PON-RoF for transmission of four 43.6 Gb/sec orthogonal frequency division multiplexing (OFDM) signals. Results showed that an acceptable BER variation for different path lengths up to 25 km was achievable for all four access points and thus the transmission of four OFDM channels is feasible for a 25 km standard single mode fiber (SSMF) path length. PMID:26153536

  1. Implementation of a new technology for point detection

    NASA Astrophysics Data System (ADS)

    Petinarides, John; Griffin, M. Todd; Miller, Ranaan A.; Nazarov, Erkinjon G.; Bashall, Anthony D.

    2005-05-01

    General Dynamics ATP (GDATP) and Sionex Corporation (Sionex) are carrying out a cooperative development for a handheld chemical agent detector, being called JUNO, which will have lower false positives, higher sensitivity, and improved interference rejection compared with presently available detectors. This enhanced performance is made possible by the use of a new principle of ion separation called Differential Mobility Spectrometry (DMS). The enhanced selectivity is provided by the field tunable nature of the Sionex differential mobility technology (microDMxTM) which forms the analytical heart of the JUNO system and enables fingerprinting of molecules by characterization of the ionized molecular behavior under multiple electric field conditions. This enhanced selectivity is valuable in addressing not only the traditional list of chemical warfare agents (CWA) but also the substantial list of Toxic Industrial Compounds (TICs) and Toxic Industrial Materials (TIMs) which may be released in warfare or terrorist situations. Experimental results showing the ability of the microDMx to reject interferences, detect and resolve live agents are presented. An additional breakthrough in the technology was realized by operating the device at a reduced pressure of around 0.5 atmospheres. This reduced pressure operation resulted in roughly doubling the spectrometers resolution over what has previously been reported [1]. Advances have also been made in power consumption and packaging leading to a device suitable for portable, handheld, applications. Experimental results illustrating the performance of the microDMx technology employed in JUNO are highlighted.

  2. Interface design challenges for single point access to diverse and dispersed science databases

    NASA Technical Reports Server (NTRS)

    Harberts, R. L.; Pfister, R. G.; Dobinson, E. R.

    1992-01-01

    Efforts to relate the diversity of terminology in science data bases in a logical way for information system interfaces are discussed. Attention is given to the NASA development of the Information Management System (V. 0 IMS), a prototypic common interface for accessing dispersed earth science data.

  3. Single Quantum Dot Analysis Enables Multiplexed Point Mutation Detection by Gap Ligase Chain Reaction

    PubMed Central

    Song, Yunke; Zhang, Yi; Wang, Tza-Huei

    2014-01-01

    Gene point mutations present important biomarkers for genetic diseases. However, existing point mutation detection methods suffer from low sensitivity, specificity, and tedious assay processes. In this report, we propose an assay technology which combines the outstanding specificity of gap ligase chain reaction (Gap-LCR), the high sensitivity of single molecule coincidence detection and superior optical properties of quantum dots (QDs) for multiplexed detection of point mutations in genomic DNA. Mutant-specific ligation products are generated by Gap-LCR and subsequently captured by QDs to form DNA-QD nanocomplexes that are detected by single molecule spectroscopy (SMS) through multi-color fluorescence burst coincidence analysis, allowing for multiplexed mutation detection in a separation-free format. The proposed assay is capable of detecting zeptomoles of KRAS codon 12 mutation variants with near 100% specificity. Its high sensitivity allows direct detection of KRAS mutation in crude genomic DNA without PCR pre-amplification. PMID:23239594

  4. Estimating the Effects of Detection Heterogeneity and Overdispersion on Trends Estimated from Avian Point Counts

    EPA Science Inventory

    Point counts are a common method for sampling avian distribution and abundance. Though methods for estimating detection probabilities are available, many analyses use raw counts and do not correct for detectability. We use a removal model of detection within an N-mixture approa...

  5. Dense central office solution for point-to-point fibre access including a novel compact dual bi-directional fibre optical transceiver

    NASA Astrophysics Data System (ADS)

    Arvidsson, Gunnar; Junique, Stéphane; Persson, Karl-Åke; Sundberg, Erland

    2006-07-01

    The centralized Point-to-Point fibre access approach with a dedicated single mode optical fibre link connecting each customer to a Central Office (CO) has advantages regarding future-proofness, security, and simple and low-cost optical links and transceivers. The potential bottleneck in handling the large number of optical fibres that need to be terminated in the CO, and combined with optoelectronic components, has been studied within the IST 6th Framework Programme integrated project MUSE. The key parts in the CO are the passive cabinet where customer fibres are accessible through fibre connectors in the Optical Distribution Frame (ODF), and the active cabinet with switching equipment and optical transceivers. For the passive cabinet we conclude, that the most efficient solution is that each connection from the active cabinet to a customer passes only one ODF, and that small form factor connectors are used. For the active cabinet we have demonstrated the feasibility of an SFF-size module containing two bi-directional transceiver units by building and successfully testing a prototype, increasing the customer port density by a factor of two compared to commercial transceivers. The power consumption, which impacts power supply, cooling and cost, has been analyzed, and we propose measures to significantly decrease the power consumption.

  6. A simple cassette as point-of-care diagnostic device for naked-eye colorimetric bacteria detection.

    PubMed

    Safavieh, Mohammadali; Ahmed, Minhaz Uddin; Sokullu, Esen; Ng, Andy; Braescu, Liliana; Zourob, Mohammed

    2014-01-21

    Effective pathogen detection is necessary for treatment of infectious diseases. Point of care (POC) devices have tremendously improved the global human heath. However, design criteria for sample processing POC devices for pathogen detection in limited infrastructure are challenging and can make a significant contribution to global health by providing rapid and sensitive detection of bacteria in food, water, and patient samples. In this paper, we demonstrate a novel portable POC diagnostic device that is simple to assemble for genetic detection of bacterial pathogens by isothermal DNA amplification. The device is fabricated with very low production cost, using simple methods and easy-to-access materials on a flexible ribbon polyethylene substrate. We showed that the device is capable of detection of 30 CFU mL(-1) of E. coli and 200 CFU mL(-1) of S. aureus in less than 1 hour. Through numerical simulations, we estimated that the device can be extended to high-throughput detection simultaneously performing a minimum of 36 analyses. This robust and sensitive detection device can be assembled and operated by non-specialist personnel, particularly for multiple bacterial pathogen detections in low-resource settings.

  7. Quantitative naturalistic methods for detecting change points in psychotherapy research: an illustration with alliance ruptures.

    PubMed

    Eubanks-Carter, Catherine; Gorman, Bernard S; Muran, J Christopher

    2012-01-01

    Analysis of change points in psychotherapy process could increase our understanding of mechanisms of change. In particular, naturalistic change point detection methods that identify turning points or breakpoints in time series data could enhance our ability to identify and study alliance ruptures and resolutions. This paper presents four categories of statistical methods for detecting change points in psychotherapy process: criterion-based methods, control chart methods, partitioning methods, and regression methods. Each method's utility for identifying shifts in the alliance is illustrated using a case example from the Beth Israel Psychotherapy Research program. Advantages and disadvantages of the various methods are discussed.

  8. One-Step Ligation on RNA Amplification for the Detection of Point Mutations.

    PubMed

    Zhang, Lei; Wang, Jingjing; Coetzer, Mia; Angione, Stephanie; Kantor, Rami; Tripathi, Anubhav

    2015-11-01

    The detection of point mutations is required in the diagnosis of many human diseases. The conformal specificity of DNA ligases was elegantly used to distinguish single-nucleotide mismatches. However, to detect point mutations in RNA retroviruses, conventional ligase-mediated approaches require the reverse transcription of viral genomes before separate ligation and amplification steps. We developed one-step ligation on RNA amplification (LRA) for the direct detection of RNA point mutations. The process combines the ligase-mediated joining of two oligonucleotides and subsequent hot start amplification into a single-tube reaction. We report that modifications to the structure of the oligonucleotide ligation probes improve the rate of ligation and the specificity of mutation detection on RNA. We applied LRA to the detection of a common, clinically relevant HIV-1 reverse transcriptase drug-resistant point mutation, K103N, and compared it with allele-specific PCR and pyrosequencing. LRA achieved a limit of specific quantitation of 1:100 (1%), and a limit of specific detection for mutant K103N RNA transcripts among excess wild-type strands of 1:10,000 (0.01%). LRA also exhibited good detection threshold of 5 × 10(2) copies/μL K103N RNA transcripts. LRA is a novel point mutation detection method, with potential utilization in HIV drug resistance detection and early diagnostics of genetic disorders associated with other infectious diseases and cancer. PMID:26322949

  9. Methodological demonstration of laser beam pointing control for space gravitational wave detection missions.

    PubMed

    Dong, Yu-Hui; Liu, He-Shan; Luo, Zi-Ren; Li, Yu-Qiong; Jin, Gang

    2014-07-01

    In space laser interferometer gravitational wave (G.W.) detection missions, the stability of the laser beam pointing direction has to be kept at 10 nrad/√Hz. Otherwise, the beam pointing jitter noise will dominate the noise budget and make the detection of G.W. impossible. Disturbed by the residue non-conservative forces, the fluctuation of the laser beam pointing direction could be a few μrad/√Hz at frequencies from 0.1 mHz to 10 Hz. Therefore, the laser beam pointing control system is an essential requirement for those space G.W. detection missions. An on-ground test of such beam pointing control system is performed, where the Differential Wave-front Sensing technique is used to sense the beams pointing jitter. An active controlled steering mirror is employed to adjust the beam pointing direction to compensate the jitter. The experimental result shows that the pointing control system can be used for very large dynamic range up to 5 μrad. At the interested frequencies of space G.W. detection missions, between 1 mHz and 1 Hz, beam pointing stability of 6 nrad/√Hz is achieved. PMID:25085155

  10. Dynamic occlusion detection and inpainting of in situ captured terrestrial laser scanning point clouds sequence

    NASA Astrophysics Data System (ADS)

    Chen, Chi; Yang, Bisheng

    2016-09-01

    Laser point clouds captured using terrestrial laser scanning (TLS) in an uncontrollable urban outdoor or indoor scene suffer from irregular shaped data blanks caused by dynamic occlusion that temporarily exists, i.e., moving objects, such as pedestrians or cars, resulting in integrality and quality losses of the scene data. This paper proposes a novel automatic dynamic occlusion detection and inpainting method for sequential TLS point clouds captured from one scan position. In situ collected laser point clouds sequences are indexed by establishing a novel panoramic space partition that assigns a three dimensional voxel to each laser point according to the scanning setups. Then two stationary background models are constructed at the ray voxel level using the laser reflectance intensity and geometrical attributes of the point set inside each voxel across the TLS sequence. Finally, the background models are combined to detect the points on the dynamic object, and the ray voxels of the detected dynamic points are tracked for further inpainting by replacing the ray voxels with the corresponding background voxels from another scan. The resulting scene is free of dynamic occlusions. Experiments validated the effectiveness of the proposed method for indoor and outdoor TLS point clouds captured by a commercial terrestrial scanner. The proposed method achieves high precision and recall rate for dynamic occlusion detection and produces clean inpainted point clouds for further processing.

  11. Methodological demonstration of laser beam pointing control for space gravitational wave detection missions

    SciTech Connect

    Dong, Yu-Hui; Liu, He-Shan; Luo, Zi-Ren; Li, Yu-Qiong; Jin, Gang

    2014-07-15

    In space laser interferometer gravitational wave (G.W.) detection missions, the stability of the laser beam pointing direction has to be kept at 10 nrad/√Hz. Otherwise, the beam pointing jitter noise will dominate the noise budget and make the detection of G.W. impossible. Disturbed by the residue non-conservative forces, the fluctuation of the laser beam pointing direction could be a few μrad/√Hz at frequencies from 0.1 mHz to 10 Hz. Therefore, the laser beam pointing control system is an essential requirement for those space G.W. detection missions. An on-ground test of such beam pointing control system is performed, where the Differential Wave-front Sensing technique is used to sense the beams pointing jitter. An active controlled steering mirror is employed to adjust the beam pointing direction to compensate the jitter. The experimental result shows that the pointing control system can be used for very large dynamic range up to 5 μrad. At the interested frequencies of space G.W. detection missions, between 1 mHz and 1 Hz, beam pointing stability of 6 nrad/√Hz is achieved.

  12. Rethinking mobile delivery: using Quick Response codes to access information at the point of need.

    PubMed

    Lombardo, Nancy T; Morrow, Anne; Le Ber, Jeanne

    2012-01-01

    This article covers the use of Quick Response (QR) codes to provide instant mobile access to information, digital collections, educational offerings, library website, subject guides, text messages, videos, and library personnel. The array of uses and the value of using QR codes to push customized information to patrons are explained. A case is developed for using QR codes for mobile delivery of customized information to patrons. Applications in use at the Libraries of the University of Utah will be reviewed to provide readers with ideas for use in their library. PMID:22289092

  13. 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.

  14. Access and Quality of HIV-Related Point-of-Care Diagnostic Testing in Global Health Programs.

    PubMed

    Fonjungo, Peter N; Boeras, Debrah I; Zeh, Clement; Alexander, Heather; Parekh, Bharat S; Nkengasong, John N

    2016-02-01

    Access to point-of-care testing (POCT) improves patient care, especially in resource-limited settings where laboratory infrastructure is poor and the bulk of the population lives in rural settings. However, because of challenges in rolling out the technology and weak quality assurance measures, the promise of human immunodeficiency virus (HIV)-related POCT in resource-limited settings has not been fully exploited to improve patient care and impact public health. Because of these challenges, the Joint United Nations Programme on HIV/AIDS (UNAIDS), in partnership with other organizations, recently launched the Diagnostics Access Initiative. Expanding HIV programs, including the "test and treat" strategies and the newly established UNAIDS 90-90-90 targets, will require increased access to reliable and accurate POCT results. In this review, we examine various components that could improve access and uptake of quality-assured POC tests to ensure coverage and public health impact. These components include evaluation, policy, regulation, and innovative approaches to strengthen the quality of POCT. PMID:26423384

  15. Identification of molecular hinge points mediating alternating access in the vesicular monoamine transporter VMAT2

    PubMed Central

    Yaffe, Dana; Radestock, Sebastian; Shuster, Yonatan; Forrest, Lucy R.; Schuldiner, Shimon

    2013-01-01

    Vesicular monoamine transporter 2 (VMAT2) catalyzes transport of monoamines into storage vesicles in a process that involves exchange of the charged monoamine with two protons. VMAT2 is a member of the DHA12 family of multidrug transporters that belongs to the major facilitator superfamily (MFS) of secondary transporters. Here we present a homology model of VMAT2, which has the standard MFS fold, that is, with two domains of six transmembrane helices each which are related by twofold pseudosymmetry and whose axis runs normal to the membrane and between the two halves. Demonstration of the essential role of a membrane-embedded glutamate and confirmation of the existence of a hydrogen bond probably involved in proton transport provide experimental evidence that validates some of the predictions inherent to the model. Moreover, we show the essential role of residues at two anchor points between the two bundles. These residues appear to function as molecular hinge points about which the two six transmembrane-helix bundles flex and straighten to open and close the pathways on either side of the membrane as required for transport. Polar residues that create a hydrogen bond cluster form one of the anchor points of VMAT2. The other results from hydrophobic interactions. Residues at the anchor points are strongly conserved in other MFS transporters in one way or another, suggesting that interactions at these locations will be critical in most, if not all, MFS transporters. PMID:23530208

  16. Point and counterpoint: patient control of access to data in their electronic health records.

    PubMed

    Caine, Kelly; Tierney, William M

    2015-01-01

    Information collection, storage, and management is central to the practice of health care. For centuries, patients' and providers' expectations kept medical records confidential between providers and patients. With the advent of electronic health records, patient health information has become more widely available to providers and health care managers and has broadened its potential use beyond individual patient care. Adhering to the principles of Fair Information Practice, including giving patients control over the availability and use of their individual health records, would improve care by fostering the sharing of sensitive information between patients and providers. However, adherence to such principles could put patients at risk for unsafe care as a result of both missed opportunities for providing needed care as well as provision of contraindicated care, as it would prevent health care providers from having full access to health information. Patients' expectations for the highest possible quality and safety of care, therefore, may be at odds with their desire to limit provider access to their health records. Conversely, provider expectations that patients would willingly seek care for embarrassing conditions and disclose sensitive information may be at odds with patients' information privacy rights. An open dialogue between patients and providers will be necessary to balance respect for patient rights with provider need for patient information.

  17. Point and counterpoint: patient control of access to data in their electronic health records.

    PubMed

    Caine, Kelly; Tierney, William M

    2015-01-01

    Information collection, storage, and management is central to the practice of health care. For centuries, patients' and providers' expectations kept medical records confidential between providers and patients. With the advent of electronic health records, patient health information has become more widely available to providers and health care managers and has broadened its potential use beyond individual patient care. Adhering to the principles of Fair Information Practice, including giving patients control over the availability and use of their individual health records, would improve care by fostering the sharing of sensitive information between patients and providers. However, adherence to such principles could put patients at risk for unsafe care as a result of both missed opportunities for providing needed care as well as provision of contraindicated care, as it would prevent health care providers from having full access to health information. Patients' expectations for the highest possible quality and safety of care, therefore, may be at odds with their desire to limit provider access to their health records. Conversely, provider expectations that patients would willingly seek care for embarrassing conditions and disclose sensitive information may be at odds with patients' information privacy rights. An open dialogue between patients and providers will be necessary to balance respect for patient rights with provider need for patient information. PMID:25480723

  18. A removal model for estimating detection probabilities from point-count surveys

    USGS Publications Warehouse

    Farnsworth, G.L.; Pollock, K.H.; Nichols, J.D.; Simons, T.R.; Hines, J.E.; Sauer, J.R.

    2002-01-01

    Use of point-count surveys is a popular method for collecting data on abundance and distribution of birds. However, analyses of such data often ignore potential differences in detection probability. We adapted a removal model to directly estimate detection probability during point-count surveys. The model assumes that singing frequency is a major factor influencing probability of detection when birds are surveyed using point counts. This may be appropriate for surveys in which most detections are by sound. The model requires counts to be divided into several time intervals. Point counts are often conducted for 10 min, where the number of birds recorded is divided into those first observed in the first 3 min, the subsequent 2 min, and the last 5 min. We developed a maximum-likelihood estimator for the detectability of birds recorded during counts divided into those intervals. This technique can easily be adapted to point counts divided into intervals of any length. We applied this method to unlimited-radius counts conducted in Great Smoky Mountains National Park. We used model selection criteria to identify whether detection probabilities varied among species, throughout the morning, throughout the season, and among different observers. We found differences in detection probability among species. Species that sing frequently such as Winter Wren (Troglodytes troglodytes) and Acadian Flycatcher (Empidonax virescens) had high detection probabilities (~90%) and species that call infrequently such as Pileated Woodpecker (Dryocopus pileatus) had low detection probability (36%). We also found detection probabilities varied with the time of day for some species (e.g. thrushes) and between observers for other species. We used the same approach to estimate detection probability and density for a subset of the observations with limited-radius point counts.

  19. Rapid detection of Ebola virus with a reagent-free, point-of-care biosensor

    SciTech Connect

    Baca, Justin T.; Severns, Virginia; Lovato, Debbie; Branch, Darren W.; Larson, Richard S.

    2015-04-14

    Surface acoustic wave (SAW) sensors can rapidly detect Ebola antigens at the point-of-care without the need for added reagents, sample processing, or specialized personnel. This preliminary study demonstrates SAW biosensor detection of the Ebola virus in a concentration-dependent manner. The detection limit with this methodology is below the average level of viremia detected on the first day of symptoms by PCR. We observe a log-linear sensor response for highly fragmented Ebola viral particles, with a detection limit corresponding to 1.9 × 10⁴ PFU/mL prior to virus inactivation. We predict greatly improved sensitivity for intact, infectious Ebola virus. This point-of-care methodology has the potential to detect Ebola viremia prior to symptom onset, greatly enabling infection control and rapid treatment. This biosensor platform is powered by disposable AA batteries and can be rapidly adapted to detect other emerging diseases in austere conditions.

  20. Rapid detection of Ebola virus with a reagent-free, point-of-care biosensor

    DOE PAGES

    Baca, Justin T.; Severns, Virginia; Lovato, Debbie; Branch, Darren W.; Larson, Richard S.

    2015-04-14

    Surface acoustic wave (SAW) sensors can rapidly detect Ebola antigens at the point-of-care without the need for added reagents, sample processing, or specialized personnel. This preliminary study demonstrates SAW biosensor detection of the Ebola virus in a concentration-dependent manner. The detection limit with this methodology is below the average level of viremia detected on the first day of symptoms by PCR. We observe a log-linear sensor response for highly fragmented Ebola viral particles, with a detection limit corresponding to 1.9 × 10⁴ PFU/mL prior to virus inactivation. We predict greatly improved sensitivity for intact, infectious Ebola virus. This point-of-care methodologymore » has the potential to detect Ebola viremia prior to symptom onset, greatly enabling infection control and rapid treatment. This biosensor platform is powered by disposable AA batteries and can be rapidly adapted to detect other emerging diseases in austere conditions.« less

  1. A removal model for estimating detection probabilities from point-count surveys

    USGS Publications Warehouse

    Farnsworth, G.L.; Pollock, K.H.; Nichols, J.D.; Simons, T.R.; Hines, J.E.; Sauer, J.R.

    2000-01-01

    We adapted a removal model to estimate detection probability during point count surveys. The model assumes one factor influencing detection during point counts is the singing frequency of birds. This may be true for surveys recording forest songbirds when most detections are by sound. The model requires counts to be divided into several time intervals. We used time intervals of 2, 5, and 10 min to develop a maximum-likelihood estimator for the detectability of birds during such surveys. We applied this technique to data from bird surveys conducted in Great Smoky Mountains National Park. We used model selection criteria to identify whether detection probabilities varied among species, throughout the morning, throughout the season, and among different observers. The overall detection probability for all birds was 75%. We found differences in detection probability among species. Species that sing frequently such as Winter Wren and Acadian Flycatcher had high detection probabilities (about 90%) and species that call infrequently such as Pileated Woodpecker had low detection probability (36%). We also found detection probabilities varied with the time of day for some species (e.g. thrushes) and between observers for other species. This method of estimating detectability during point count surveys offers a promising new approach to using count data to address questions of the bird abundance, density, and population trends.

  2. A double-observer approach for estimating detection probability and abundance from point counts

    USGS Publications Warehouse

    Nichols, J.D.; Hines, J.E.; Sauer, J.R.; Fallon, F.W.; Fallon, J.E.; Heglund, P.J.

    2000-01-01

    Although point counts are frequently used in ornithological studies, basic assumptions about detection probabilities often are untested. We apply a double-observer approach developed to estimate detection probabilities for aerial surveys (Cook and Jacobson 1979) to avian point counts. At each point count, a designated 'primary' observer indicates to another ('secondary') observer all birds detected. The secondary observer records all detections of the primary observer as well as any birds not detected by the primary observer. Observers alternate primary and secondary roles during the course of the survey. The approach permits estimation of observer-specific detection probabilities and bird abundance. We developed a set of models that incorporate different assumptions about sources of variation (e.g. observer, bird species) in detection probability. Seventeen field trials were conducted, and models were fit to the resulting data using program SURVIV. Single-observer point counts generally miss varying proportions of the birds actually present, and observer and bird species were found to be relevant sources of variation in detection probabilities. Overall detection probabilities (probability of being detected by at least one of the two observers) estimated using the double-observer approach were very high (>0.95), yielding precise estimates of avian abundance. We consider problems with the approach and recommend possible solutions, including restriction of the approach to fixed-radius counts to reduce the effect of variation in the effective radius of detection among various observers and to provide a basis for using spatial sampling to estimate bird abundance on large areas of interest. We believe that most questions meriting the effort required to carry out point counts also merit serious attempts to estimate detection probabilities associated with the counts. The double-observer approach is a method that can be used for this purpose.

  3. Abrupt change point detection of annual maximum precipitation using fused lasso

    NASA Astrophysics Data System (ADS)

    Jeon, Jong-June; Sung, Jang Hyun; Chung, Eun-Sung

    2016-07-01

    Because the widely used Bayesian change point analysis (BCPA) is generally applied to the normal distribution, it cannot be freely used to the annual maximum precipitations (AMP) in South Korea. Therefore, this study proposed the fused lasso penalty function to detect the change point of AMP which can be generally fitted by using the Generalized Extreme Value (GEV) distribution in South Korea. First, four numerical experiments are conducted to compare the detection performances between BCPA and fused lasso method. As a result, fused lasso shows the superiority of the data generated by GEV distribution having skewness. The fused lasso method is applied to 63 weather stations in South Korea and then 17 stations having any change points from BCPA and the GEV fused lasso are analyzed. Similar to the numerical analyses, the GEV fused lasso method can delicately detect the change point of AMPs. After the change point, the means of AMPs did not go back to the previous. Alternately, BCPA can be stated to find variation points not change points because the means returned to their original values as time progressed. Therefore, it can be concluded that the GEV fused lasso method detects the change points of non-stationary AMPs of South Korea. This study can be extended to more extreme distributions for various meteorological variables.

  4. Access to Mars from Earth-Moon Libration Point Orbits:. [Manifold and Direct Options

    NASA Technical Reports Server (NTRS)

    Kakoi, Masaki; Howell, Kathleen C.; Folta, David

    2014-01-01

    This investigation is focused specifically on transfers from Earth-Moon L(sub 1)/L(sub 2) libration point orbits to Mars. Initially, the analysis is based in the circular restricted three-body problem to utilize the framework of the invariant manifolds. Various departure scenarios are compared, including arcs that leverage manifolds associated with the Sun-Earth L(sub 2) orbits as well as non-manifold trajectories. For the manifold options, ballistic transfers from Earth-Moon L(sub 2) libration point orbits to Sun-Earth L(sub 1)/L(sub 2) halo orbits are first computed. This autonomous procedure applies to both departure and arrival between the Earth-Moon and Sun-Earth systems. Departure times in the lunar cycle, amplitudes and types of libration point orbits, manifold selection, and the orientation/location of the surface of section all contribute to produce a variety of options. As the destination planet, the ephemeris position for Mars is employed throughout the analysis. The complete transfer is transitioned to the ephemeris model after the initial design phase. Results for multiple departure/arrival scenarios are compared.

  5. Access to Mars from Earth-Moon libration point orbits: Manifold and direct options

    NASA Astrophysics Data System (ADS)

    Kakoi, Masaki; Howell, Kathleen C.; Folta, David

    2014-09-01

    This investigation is focused specifically on transfers from Earth-Moon L1/L2 libration point orbits to Mars. Initially, the analysis is based on the circular restricted three-body problem to utilize the framework of the invariant manifolds. Various departure scenarios are compared, including arcs that leverage manifolds associated with the Sun-Earth L2 orbits as well as non-manifold trajectories. For the manifold options, ballistic transfers from Earth-Moon L2 libration point orbits to Sun-Earth L1/L2 halo orbits are first computed. This autonomous procedure applies to both departure and arrival between the Earth-Moon and Sun-Earth systems. Departure times in the lunar cycle, amplitudes and types of libration point orbits, manifold selection, and the orientation/location of the surface of section all contribute to produce a variety of options. As the destination planet, the ephemeris position for Mars is employed throughout the analysis. The complete transfer is transitioned to the ephemeris model after the initial design phase. Results for multiple departure/arrival scenarios are compared.

  6. Water Quality vs. Sanitation Accessibility: What is the most effective intervention point for preventing cholera in Dhaka, Bangladesh?

    NASA Astrophysics Data System (ADS)

    Majumder, M. S.; Gute, D.; Faruque, A. S.

    2011-12-01

    Every year, 3 to 5 million individuals contract cholera, an acute diarrheal infection that is caused by the ingestion of food or water containing the Vibrio cholerae bacterium. Because cholera is a waterborne disease, it can be transmitted quickly in environments with inadequate water and sanitation systems where infected waste can easily pollute drinking water. Today, Bangladesh continues to struggle with endemic cholera. Donor organizations address water and sanitation via localized initiatives, including the installation of community water collection sites (i.e. tubewells; water-boiling points; etc.). At this small-scale level, water quality and sanitation accessibility can be improved independently of one another, and when resources are limited, donors must invest in the most effective disease prevention options. This study used laboratory-confirmed cholera incidence data (2000-2009) collected by the International Centre of Diarrheal Disease Research, Bangladesh at their on-site hospital to compare the efficacy of interventions addressing water quality versus sanitation accessibility in Dhaka, Bangladesh. Data regarding use of sanitary latrines and boiling of drinking water were extracted from sequential patient interviews conducted at the Dhaka facility and used as surrogate variables for sanitation accessibility and water quality respectively. Our analysis indicates that boiling water is 10 times more effective at preventing cholera than the use of a sanitary latrine. This finding suggests that regulating water quality is perhaps more critical to cholera prevention than increasing sanitation accessibility in an urban environment like that of Dhaka. At present, WaterAid - one of Bangladesh's most significant water and sanitation donor organizations - invests the majority of its budget on improving sanitation accessibility. The World Health Organization and the United Nations Millennium Development Goals also prioritize sanitation accessibility. However, in

  7. Functional requirements with survey results for integrated intrusion detection and access control annunciator systems

    SciTech Connect

    Arakaki, L.H.; Monaco, F.M.

    1995-09-01

    This report contains the guidance Functional Requirements for an Integrated Intrusion Detection and Access Control Annunciator System, and survey results of selected commercial systems. The survey questions were based upon the functional requirements; therefore, the results reflect which and sometimes how the guidance recommendations were met.

  8. Comparison of methods for accurate end-point detection of potentiometric titrations

    NASA Astrophysics Data System (ADS)

    Villela, R. L. A.; Borges, P. P.; Vyskočil, L.

    2015-01-01

    Detection of the end point in potentiometric titrations has wide application on experiments that demand very low measurement uncertainties mainly for certifying reference materials. Simulations of experimental coulometric titration data and consequential error analysis of the end-point values were conducted using a programming code. These simulations revealed that the Levenberg-Marquardt method is in general more accurate than the traditional second derivative technique used currently as end-point detection for potentiometric titrations. Performance of the methods will be compared and presented in this paper.

  9. A novel infrared small moving target detection method based on tracking interest points under complicated background

    NASA Astrophysics Data System (ADS)

    Dong, Xiabin; Huang, Xinsheng; Zheng, Yongbin; Bai, Shengjian; Xu, Wanying

    2014-07-01

    Infrared moving target detection is an important part of infrared technology. We introduce a novel infrared small moving target detection method based on tracking interest points under complicated background. Firstly, Difference of Gaussians (DOG) filters are used to detect a group of interest points (including the moving targets). Secondly, a sort of small targets tracking method inspired by Human Visual System (HVS) is used to track these interest points for several frames, and then the correlations between interest points in the first frame and the last frame are obtained. Last, a new clustering method named as R-means is proposed to divide these interest points into two groups according to the correlations, one is target points and another is background points. In experimental results, the target-to-clutter ratio (TCR) and the receiver operating characteristics (ROC) curves are computed experimentally to compare the performances of the proposed method and other five sophisticated methods. From the results, the proposed method shows a better discrimination of targets and clutters and has a lower false alarm rate than the existing moving target detection methods.

  10. Hierarchical clustering of EMD based interest points for road sign detection

    NASA Astrophysics Data System (ADS)

    Khan, Jesmin; Bhuiyan, Sharif; Adhami, Reza

    2014-04-01

    This paper presents an automatic road traffic signs detection and recognition system based on hierarchical clustering of interest points and joint transform correlation. The proposed algorithm consists of the three following stages: interest points detection, clustering of those points and similarity search. At the first stage, good discriminative, rotation and scale invariant interest points are selected from the image edges based on the 1-D empirical mode decomposition (EMD). We propose a two-step unsupervised clustering technique, which is adaptive and based on two criterion. In this context, the detected points are initially clustered based on the stable local features related to the brightness and color, which are extracted using Gabor filter. Then points belonging to each partition are reclustered depending on the dispersion of the points in the initial cluster using position feature. This two-step hierarchical clustering yields the possible candidate road signs or the region of interests (ROIs). Finally, a fringe-adjusted joint transform correlation (JTC) technique is used for matching the unknown signs with the existing known reference road signs stored in the database. The presented framework provides a novel way to detect a road sign from the natural scenes and the results demonstrate the efficacy of the proposed technique, which yields a very low false hit rate.

  11. A Novel Line Space Voting Method for Vanishing-Point Detection of General Road Images

    PubMed Central

    Wu, Zongsheng; Fu, Weiping; Xue, Ru; Wang, Wen

    2016-01-01

    Vanishing-point detection is an important component for the visual navigation system of an autonomous mobile robot. In this paper, we present a novel line space voting method for fast vanishing-point detection. First, the line segments are detected from the road image by the line segment detector (LSD) method according to the pixel’s gradient and texture orientation computed by the Sobel operator. Then, the vanishing-point of the road is voted on by considering the points of the lines and their neighborhood spaces with weighting methods. Our algorithm is simple, fast, and easy to implement with high accuracy. It has been experimentally tested with over hundreds of structured and unstructured road images. The experimental results indicate that the proposed method is effective and can meet the real-time requirements of navigation for autonomous mobile robots and unmanned ground vehicles. PMID:27347947

  12. A Novel Line Space Voting Method for Vanishing-Point Detection of General Road Images.

    PubMed

    Wu, Zongsheng; Fu, Weiping; Xue, Ru; Wang, Wen

    2016-01-01

    Vanishing-point detection is an important component for the visual navigation system of an autonomous mobile robot. In this paper, we present a novel line space voting method for fast vanishing-point detection. First, the line segments are detected from the road image by the line segment detector (LSD) method according to the pixel's gradient and texture orientation computed by the Sobel operator. Then, the vanishing-point of the road is voted on by considering the points of the lines and their neighborhood spaces with weighting methods. Our algorithm is simple, fast, and easy to implement with high accuracy. It has been experimentally tested with over hundreds of structured and unstructured road images. The experimental results indicate that the proposed method is effective and can meet the real-time requirements of navigation for autonomous mobile robots and unmanned ground vehicles. PMID:27347947

  13. Detection of fiducial points in ECG waves using iteration based adaptive thresholds.

    PubMed

    Wonjune Kang; Kyunguen Byun; Hong-Goo Kang

    2015-08-01

    This paper presents an algorithm for the detection of fiducial points in electrocardiogram (ECG) waves using iteration based adaptive thresholds. By setting the search range of the processing frame to the interval between two consecutive R peaks, the peaks of T and P waves are used as reference salient points (RSPs) to detect the fiducial points. The RSPs are selected from candidates whose slope variation factors are larger than iteratively defined adaptive thresholds. Considering the fact that the number of RSPs varies depending on whether the ECG wave is normal or not, the proposed algorithm proceeds with a different methodology for determining fiducial points based on the number of detected RSPs. Testing was performed using twelve records from the MIT-BIH Arrhythmia Database that were manually marked for comparison with the estimated locations of the fiducial points. The means of absolute distances between the true locations and the points estimated by the algorithm are 12.2 ms and 7.9 ms for the starting points of P and Q waves, and 9.3 ms and 13.9 ms for the ending points of S and T waves. Since the computational complexity of the proposed algorithm is very low, it is feasible for use in mobile devices. PMID:26736854

  14. Multi-scale quantum point contact model for filamentary conduction in resistive random access memories devices

    SciTech Connect

    Lian, Xiaojuan Cartoixà, Xavier; Miranda, Enrique; Suñé, Jordi; Perniola, Luca; Rurali, Riccardo; Long, Shibing; Liu, Ming

    2014-06-28

    We depart from first-principle simulations of electron transport along paths of oxygen vacancies in HfO{sub 2} to reformulate the Quantum Point Contact (QPC) model in terms of a bundle of such vacancy paths. By doing this, the number of model parameters is reduced and a much clearer link between the microscopic structure of the conductive filament (CF) and its electrical properties can be provided. The new multi-scale QPC model is applied to two different HfO{sub 2}-based devices operated in the unipolar and bipolar resistive switching (RS) modes. Extraction of the QPC model parameters from a statistically significant number of CFs allows revealing significant structural differences in the CF of these two types of devices and RS modes.

  15. Increment of Access Points in Integrated System of Wavelength Division Multiplexed Passive Optical Network Radio over Fiber

    PubMed Central

    Amiri, I. S.; Alavi, S. E.; Soltanian, M. R. K.; Fisal, N.; Supa’at, A. S. M.; Ahmad, H.

    2015-01-01

    This paper describes a novel technique to increase the numbers of access points (APs) in a wavelength division multiplexed-passive optical network (WDM-PON) integrated in a 100 GHz radio-over-fiber (RoF). Eight multi-carriers separated by 25 GHz intervals were generated in the range of 193.025 to 193.200 THz using a microring resonator (MRR) system incorporating an add-drop filter system. All optically generated multi-carriers were utilized in an integrated system of WDM-PON-RoF for transmission of four 43.6 Gb/sec orthogonal frequency division multiplexing (OFDM) signals. Results showed that an acceptable BER variation for different path lengths up to 25 km was achievable for all four access points and thus the transmission of four OFDM channels is feasible for a 25 km standard single mode fiber (SSMF) path length. PMID:26153536

  16. A 3D clustering approach for point clouds to detect and quantify changes at a rock glacier front

    NASA Astrophysics Data System (ADS)

    Micheletti, Natan; Tonini, Marj; Lane, Stuart N.

    2016-04-01

    points (i) at a maximum distance (ii) around each core-point. Under this condition, seed points are said to be density-reachable by a core point delimiting a cluster around it. A chain of intermediate seed-points can connect contiguous clusters allowing clusters of arbitrary shape to be defined. The novelty of the proposed approach consists in the implementation of the DBSCAN 3D-module, where the xyz-coordinates identify each point and the density of points within a sphere is considered. This allows detecting volumetric features with a higher accuracy, depending only on actual sampling resolution. The approach is truly 3D and exploits all TLS measurements without the need of interpolation or data reduction. Using this method, enhanced geomorphological activity during the summer of 2015 in respect to the previous two years was observed. We attribute this result to the exceptionally high temperatures of that summer, which we deem responsible for accelerating the melting process at the rock glacier front and probably also increasing creep velocities. References: - Tonini, M. and Abellan, A. (2014). Rockfall detection from terrestrial LiDAR point clouds: A clustering approach using R. Journal of Spatial Information Sciences. Number 8, pp95-110 - Hennig, C. Package fpc: Flexible procedures for clustering. https://cran.r-project.org/web/packages/fpc/index.html, 2015. Accessed 2016-01-12.

  17. Automatic roof plane detection and analysis in airborne lidar point clouds for solar potential assessment.

    PubMed

    Jochem, Andreas; Höfle, Bernhard; Rutzinger, Martin; Pfeifer, Norbert

    2009-01-01

    A relative height threshold is defined to separate potential roof points from the point cloud, followed by a segmentation of these points into homogeneous areas fulfilling the defined constraints of roof planes. The normal vector of each laser point is an excellent feature to decompose the point cloud into segments describing planar patches. An object-based error assessment is performed to determine the accuracy of the presented classification. It results in 94.4% completeness and 88.4% correctness. Once all roof planes are detected in the 3D point cloud, solar potential analysis is performed for each point. Shadowing effects of nearby objects are taken into account by calculating the horizon of each point within the point cloud. Effects of cloud cover are also considered by using data from a nearby meteorological station. As a result the annual sum of the direct and diffuse radiation for each roof plane is derived. The presented method uses the full 3D information for both feature extraction and solar potential analysis, which offers a number of new applications in fields where natural processes are influenced by the incoming solar radiation (e.g., evapotranspiration, distribution of permafrost). The presented method detected fully automatically a subset of 809 out of 1,071 roof planes where the arithmetic mean of the annual incoming solar radiation is more than 700 kWh/m(2).

  18. Evaluation of generic medical information accessed via mobile phones at the point of care in resource-limited settings

    PubMed Central

    Goldbach, Hayley; Chang, Aileen Y; Kyer, Andrea; Ketshogileng, Dineo; Taylor, Lynne; Chandra, Amit; Dacso, Matthew; Kung, Shiang-Ju; Rijken, Taatske; Fontelo, Paul; Littman-Quinn, Ryan; Seymour, Anne K; Kovarik, Carrie L

    2014-01-01

    Objective Many mobile phone resources have been developed to increase access to health education in the developing world, yet few studies have compared these resources or quantified their performance in a resource-limited setting. This study aims to compare the performance of resident physicians in answering clinical scenarios using PubMed abstracts accessed via the PubMed for Handhelds (PubMed4Hh) website versus medical/drug reference applications (Medical Apps) accessed via software on the mobile phone. Methods A two-arm comparative study with crossover design was conducted. Subjects, who were resident physicians at the University of Botswana, completed eight scenarios, each with multi-part questions. The primary outcome was a grade for each question. The primary independent variable was the intervention arm and other independent variables included residency and question. Results Within each question type there were significant differences in ‘percentage correct’ between Medical Apps and PubMed4Hh for three of the six types of questions: drug-related, diagnosis/definitions, and treatment/management. Within each of these question types, Medical Apps had a higher percentage of fully correct responses than PubMed4Hh (63% vs 13%, 33% vs 12%, and 41% vs 13%, respectively). PubMed4Hh performed better for epidemiologic questions. Conclusions While mobile access to primary literature remains important and serves an information niche, mobile applications with condensed content may be more appropriate for point-of-care information needs. Further research is required to examine the specific information needs of clinicians in resource-limited settings and to evaluate the appropriateness of current resources in bridging location- and context-specific information gaps. PMID:23535665

  19. Urban Road Detection in Airbone Laser Scanning Point Cloud Using Random Forest Algorithm

    NASA Astrophysics Data System (ADS)

    Kaczałek, B.; Borkowski, A.

    2016-06-01

    The objective of this research is to detect points that describe a road surface in an unclassified point cloud of the airborne laser scanning (ALS). For this purpose we use the Random Forest learning algorithm. The proposed methodology consists of two stages: preparation of features and supervised point cloud classification. In this approach we consider ALS points, representing only the last echo. For these points RGB, intensity, the normal vectors, their mean values and the standard deviations are provided. Moreover, local and global height variations are taken into account as components of a feature vector. The feature vectors are calculated on a basis of the 3D Delaunay triangulation. The proposed methodology was tested on point clouds with the average point density of 12 pts/m2 that represent large urban scene. The significance level of 15% was set up for a decision tree of the learning algorithm. As a result of the Random Forest classification we received two subsets of ALS points. One of those groups represents points belonging to the road network. After the classification evaluation we achieved from 90% of the overall classification accuracy. Finally, the ALS points representing roads were merged and simplified into road network polylines using morphological operations.

  20. Method and apparatus for automatically detecting patterns in digital point-ordered signals

    SciTech Connect

    Brudnoy, D.M.

    1996-12-31

    The present invention is a method and system for detecting a physical feature of a test piece by detecting a pattern in a signal representing data from inspection of the test piece. The pattern is detected by automated additive decomposition of a digital point-ordered signal which represents the data. The present invention can properly handle a non-periodic signal. A physical parameter of the test piece is measured. A digital point-ordered signal representative of the measured physical parameter is generated. The digital point-ordered signal is decomposed into a baseline signal, a background noise signal, and a peaks/troughs signal. The peaks/troughs from the peaks/troughs signal are located and peaks/troughs information indicating the physical feature of the test piece is output.

  1. The future point-of-care detection of disease and its data capture and handling.

    PubMed

    Lopez-Barbosa, Natalia; Gamarra, Jorge D; Osma, Johann F

    2016-04-01

    Point-of-care detection is a widely studied area that attracts effort and interest from a large number of fields and companies. However, there is also increased interest from the general public in this type of device, which has driven enormous changes in the design and conception of these developments and the way data is handled. Therefore, future point-of-care detection has to include communication with front-end technology, such as smartphones and networks, automation of manufacture, and the incorporation of concepts like the Internet of Things (IoT) and cloud computing. Three key examples, based on different sensing technology, are analyzed in detail on the basis of these items to highlight a route for the future design and development of point-of-care detection devices and their data capture and handling.

  2. The future point-of-care detection of disease and its data capture and handling.

    PubMed

    Lopez-Barbosa, Natalia; Gamarra, Jorge D; Osma, Johann F

    2016-04-01

    Point-of-care detection is a widely studied area that attracts effort and interest from a large number of fields and companies. However, there is also increased interest from the general public in this type of device, which has driven enormous changes in the design and conception of these developments and the way data is handled. Therefore, future point-of-care detection has to include communication with front-end technology, such as smartphones and networks, automation of manufacture, and the incorporation of concepts like the Internet of Things (IoT) and cloud computing. Three key examples, based on different sensing technology, are analyzed in detail on the basis of these items to highlight a route for the future design and development of point-of-care detection devices and their data capture and handling. PMID:26780711

  3. Automatic end-point detection of spray etching in application to mask making

    SciTech Connect

    Mizuno, F.; Kato, M.; Koizumi, T.; Mori, K.; Sagawara, K.; Takehana, Y.

    1985-06-01

    The development of high performance LSI's has increased the requirement for precise control of mask making in addition to that of wafer processing. One method for obtaining precise control is ''in-process'' end-point detection. End-point detection methods have previously been devised for thin film formation, such as thickness control of SOS (silicon-on-sapphire) epitaxial layers (1), homoepitaxial layers (2), and for plasma etching (3). In mask making, ''wet etching'' has been used due to thin Cr film deposited on mask blanks and to flat surface in comparison with the wafer fabrication. In this note, a novel method of the end-point detection used for the mask making will be reported; it is quite different from that used for the ''dry etching.''

  4. Method and apparatus for automatically detecting patterns in digital point-ordered signals

    DOEpatents

    Brudnoy, D.M.

    1998-10-20

    The present invention is a method and system for detecting a physical feature of a test piece by detecting a pattern in a signal representing data from inspection of the test piece. The pattern is detected by automated additive decomposition of a digital point-ordered signal which represents the data. The present invention can properly handle a non-periodic signal. A physical parameter of the test piece is measured. A digital point-ordered signal representative of the measured physical parameter is generated. The digital point-ordered signal is decomposed into a baseline signal, a background noise signal, and a peaks/troughs signal. The peaks/troughs from the peaks/troughs signal are located and peaks/troughs information indicating the physical feature of the test piece is output. 14 figs.

  5. Method and apparatus for automatically detecting patterns in digital point-ordered signals

    DOEpatents

    Brudnoy, David M.

    1998-01-01

    The present invention is a method and system for detecting a physical feature of a test piece by detecting a pattern in a signal representing data from inspection of the test piece. The pattern is detected by automated additive decomposition of a digital point-ordered signal which represents the data. The present invention can properly handle a non-periodic signal. A physical parameter of the test piece is measured. A digital point-ordered signal representative of the measured physical parameter is generated. The digital point-ordered signal is decomposed into a baseline signal, a background noise signal, and a peaks/troughs signal. The peaks/troughs from the peaks/troughs signal are located and peaks/troughs information indicating the physical feature of the test piece is output.

  6. A simple 96 well microfluidic chip combined with visual and densitometry detection for resource-poor point of care testing

    PubMed Central

    Yang, Minghui; Sun, Steven; Kostov, Yordan

    2010-01-01

    There is a well-recognized need for low cost biodetection technologies for resource-poor settings with minimal medical infrastructure. Lab-on-a-chip (LOC) technology has the ability to perform biological assays in such settings. The aim of this work is to develop a low cost, high-throughput detection system for the analysis of 96 samples simultaneously outside the laboratory setting. To achieve this aim, several biosensing elements were combined: a syringe operated ELISA lab-on-a-chip (ELISA-LOC) which integrates fluid delivery system into a miniature 96-well plate; a simplified non-enzymatic reporter and detection approach using a gold nanoparticle-antibody conjugate as a secondary antibody and silver enhancement of the visual signal; and Carbon nanotubes (CNT) to increase primary antibody immobilization and improve assay sensitivity. Combined, these elements obviate the need for an ELISA washer, electrical power for operation and a sophisticated detector. We demonstrate the use of the device for detection of Staphylococcal enterotoxin B, a major foodborne toxin using three modes of detection, visual detection, CCD camera and document scanner. With visual detection or using a document scanner to measure the signal, the limit of detection (LOD) was 0.5ng/ml. In addition to visual detection, for precise quantitation of signal using densitometry and a CCD camera, the LOD was 0.1ng/ml for the CCD analysis and 0.5 ng/ml for the document scanner. The observed sensitivity is in the same range as laboratory-based ELISA testing. The point of care device can analyze 96 samples simultaneously, permitting high throughput diagnostics in the field and in resource poor areas without ready access to laboratory facilities or electricity. PMID:21503269

  7. Automatic detection of exogenous respiration end-point using artificial neural network.

    PubMed

    Bisschops, I; Spanjers, H; Keesman, K

    2006-01-01

    When aerobic bacteria receive a biodegradable material such as wastewater, then respiration changes from endogenous to exogenous. The reverse occurs when biodegradation is complete. When using respirometry a respirogram is recorded showing those changes in respiration, and for an expert it is not difficult to point the moments at which they occur. The area corresponding to the exogenous respiration phase is a measure of the easily biodegradable fraction of material, also called the short-term BOD or BOD(ST). That value, in combination with a value for COD, can be used to determine the treatability of wastewater. Respirometry can also be applied on-line, e.g. for on-line monitoring of wastewater. However, automatic detection of the end-point of exogenous respiration is difficult. The first step towards on-line monitoring of wastewater treatability is to make automatic detection of this end-point possible. In this study the use of a neural network for detection of this end-point was investigated. Results are promising; after training the neural network is able to detect the correct end-point in the majority of the studied cases.

  8. Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

    NASA Astrophysics Data System (ADS)

    Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

    2014-09-01

    A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

  9. Recent improvements and testing of a check point explosives detection system

    NASA Astrophysics Data System (ADS)

    Waterbury, Rob; Vunck, Darius; Hopkins, Adam J.; Pohl, Ken; Ford, Alan; Dottery, Ed

    2012-06-01

    Alakai Defense Systems has created a standoff explosive detection sensor called the Check Point Explosives Detection System for use at military check points. The system is designed to find trace level explosive residues from a standoff distance to thwart the transport and use of illegal homemade explosives, precursors and related contraband. Because of its standoff nature, this instrument could offer benefits to those searching for explosives, since it removes the searcher from harm's way if a detonation occurs. A short description of the instrument, improvements to the system over the past year, and a brief overview of recent testing are presented here.

  10. Traffic sign detection in MLS acquired point clouds for geometric and image-based semantic inventory

    NASA Astrophysics Data System (ADS)

    Soilán, Mario; Riveiro, Belén; Martínez-Sánchez, Joaquín; Arias, Pedro

    2016-04-01

    Nowadays, mobile laser scanning has become a valid technology for infrastructure inspection. This technology permits collecting accurate 3D point clouds of urban and road environments and the geometric and semantic analysis of data became an active research topic in the last years. This paper focuses on the detection of vertical traffic signs in 3D point clouds acquired by a LYNX Mobile Mapper system, comprised of laser scanning and RGB cameras. Each traffic sign is automatically detected in the LiDAR point cloud, and its main geometric parameters can be automatically extracted, therefore aiding the inventory process. Furthermore, the 3D position of traffic signs are reprojected on the 2D images, which are spatially and temporally synced with the point cloud. Image analysis allows for recognizing the traffic sign semantics using machine learning approaches. The presented method was tested in road and urban scenarios in Galicia (Spain). The recall results for traffic sign detection are close to 98%, and existing false positives can be easily filtered after point cloud projection. Finally, the lack of a large, publicly available Spanish traffic sign database is pointed out.

  11. Secure Access Control and Large Scale Robust Representation for Online Multimedia Event Detection

    PubMed Central

    Liu, Changyu; Li, Huiling

    2014-01-01

    We developed an online multimedia event detection (MED) system. However, there are a secure access control issue and a large scale robust representation issue when we want to integrate traditional event detection algorithms into the online environment. For the first issue, we proposed a tree proxy-based and service-oriented access control (TPSAC) model based on the traditional role based access control model. Verification experiments were conducted on the CloudSim simulation platform, and the results showed that the TPSAC model is suitable for the access control of dynamic online environments. For the second issue, inspired by the object-bank scene descriptor, we proposed a 1000-object-bank (1000OBK) event descriptor. Feature vectors of the 1000OBK were extracted from response pyramids of 1000 generic object detectors which were trained on standard annotated image datasets, such as the ImageNet dataset. A spatial bag of words tiling approach was then adopted to encode these feature vectors for bridging the gap between the objects and events. Furthermore, we performed experiments in the context of event classification on the challenging TRECVID MED 2012 dataset, and the results showed that the robust 1000OBK event descriptor outperforms the state-of-the-art approaches. PMID:25147840

  12. Secure access control and large scale robust representation for online multimedia event detection.

    PubMed

    Liu, Changyu; Lu, Bin; Li, Huiling

    2014-01-01

    We developed an online multimedia event detection (MED) system. However, there are a secure access control issue and a large scale robust representation issue when we want to integrate traditional event detection algorithms into the online environment. For the first issue, we proposed a tree proxy-based and service-oriented access control (TPSAC) model based on the traditional role based access control model. Verification experiments were conducted on the CloudSim simulation platform, and the results showed that the TPSAC model is suitable for the access control of dynamic online environments. For the second issue, inspired by the object-bank scene descriptor, we proposed a 1000-object-bank (1000OBK) event descriptor. Feature vectors of the 1000OBK were extracted from response pyramids of 1000 generic object detectors which were trained on standard annotated image datasets, such as the ImageNet dataset. A spatial bag of words tiling approach was then adopted to encode these feature vectors for bridging the gap between the objects and events. Furthermore, we performed experiments in the context of event classification on the challenging TRECVID MED 2012 dataset, and the results showed that the robust 1000OBK event descriptor outperforms the state-of-the-art approaches.

  13. Fault Detection and Diagnosis of Railway Point Machines by Sound Analysis

    PubMed Central

    Lee, Jonguk; Choi, Heesu; Park, Daihee; Chung, Yongwha; Kim, Hee-Young; Yoon, Sukhan

    2016-01-01

    Railway point devices act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Point failure can significantly affect railway operations, with potentially disastrous consequences. Therefore, early detection of anomalies is critical for monitoring and managing the condition of rail infrastructure. We present a data mining solution that utilizes audio data to efficiently detect and diagnose faults in railway condition monitoring systems. The system enables extracting mel-frequency cepstrum coefficients (MFCCs) from audio data with reduced feature dimensions using attribute subset selection, and employs support vector machines (SVMs) for early detection and classification of anomalies. Experimental results show that the system enables cost-effective detection and diagnosis of faults using a cheap microphone, with accuracy exceeding 94.1% whether used alone or in combination with other known methods. PMID:27092509

  14. Fault Detection and Diagnosis of Railway Point Machines by Sound Analysis.

    PubMed

    Lee, Jonguk; Choi, Heesu; Park, Daihee; Chung, Yongwha; Kim, Hee-Young; Yoon, Sukhan

    2016-04-16

    Railway point devices act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Point failure can significantly affect railway operations, with potentially disastrous consequences. Therefore, early detection of anomalies is critical for monitoring and managing the condition of rail infrastructure. We present a data mining solution that utilizes audio data to efficiently detect and diagnose faults in railway condition monitoring systems. The system enables extracting mel-frequency cepstrum coefficients (MFCCs) from audio data with reduced feature dimensions using attribute subset selection, and employs support vector machines (SVMs) for early detection and classification of anomalies. Experimental results show that the system enables cost-effective detection and diagnosis of faults using a cheap microphone, with accuracy exceeding 94.1% whether used alone or in combination with other known methods.

  15. Preliminary Study on Appearance-Based Detection of Anatomical Point Landmarks in Body Trunk CT Images

    NASA Astrophysics Data System (ADS)

    Nemoto, Mitsutaka; Nomura, Yukihiro; Hanaoka, Shohei; Masutani, Yoshitaka; Yoshikawa, Takeharu; Hayashi, Naoto; Yoshioka, Naoki; Ohtomo, Kuni

    Anatomical point landmarks as most primitive anatomical knowledge are useful for medical image understanding. In this study, we propose a detection method for anatomical point landmark based on appearance models, which include gray-level statistical variations at point landmarks and their surrounding area. The models are built based on results of Principal Component Analysis (PCA) of sample data sets. In addition, we employed generative learning method by transforming ROI of sample data. In this study, we evaluated our method with 24 data sets of body trunk CT images and obtained 95.8 ± 7.3 % of the average sensitivity in 28 landmarks.

  16. The International Mouse Phenotyping Consortium Web Portal, a unified point of access for knockout mice and related phenotyping data.

    PubMed

    Koscielny, Gautier; Yaikhom, Gagarine; Iyer, Vivek; Meehan, Terrence F; Morgan, Hugh; Atienza-Herrero, Julian; Blake, Andrew; Chen, Chao-Kung; Easty, Richard; Di Fenza, Armida; Fiegel, Tanja; Grifiths, Mark; Horne, Alan; Karp, Natasha A; Kurbatova, Natalja; Mason, Jeremy C; Matthews, Peter; Oakley, Darren J; Qazi, Asfand; Regnart, Jack; Retha, Ahmad; Santos, Luis A; Sneddon, Duncan J; Warren, Jonathan; Westerberg, Henrik; Wilson, Robert J; Melvin, David G; Smedley, Damian; Brown, Steve D M; Flicek, Paul; Skarnes, William C; Mallon, Ann-Marie; Parkinson, Helen

    2014-01-01

    The International Mouse Phenotyping Consortium (IMPC) web portal (http://www.mousephenotype.org) provides the biomedical community with a unified point of access to mutant mice and rich collection of related emerging and existing mouse phenotype data. IMPC mouse clinics worldwide follow rigorous highly structured and standardized protocols for the experimentation, collection and dissemination of data. Dedicated 'data wranglers' work with each phenotyping center to collate data and perform quality control of data. An automated statistical analysis pipeline has been developed to identify knockout strains with a significant change in the phenotype parameters. Annotation with biomedical ontologies allows biologists and clinicians to easily find mouse strains with phenotypic traits relevant to their research. Data integration with other resources will provide insights into mammalian gene function and human disease. As phenotype data become available for every gene in the mouse, the IMPC web portal will become an invaluable tool for researchers studying the genetic contributions of genes to human diseases.

  17. Not Just a Drop in the Bucket: Expanding Access to Point-of-Use Water Treatment Systems

    PubMed Central

    Mintz, Eric; Bartram, Jamie; Lochery, Peter; Wegelin, Martin

    2001-01-01

    Since 1990, the number of people without access to safe water sources has remained constant at approximately 1.1 billion, of whom approximately 2.2 million die of waterborne disease each year. In developing countries, population growth and migrations strain existing water and sanitary infrastructure and complicate planning and construction of new infrastructure. Providing safe water for all is a long-term goal; however, relying only on time- and resource-intensive centralized solutions such as piped, treated water will leave hundreds of millions of people without safe water far into the future. Self-sustaining, decentralized approaches to making drinking water safe, including point-of-use chemical and solar disinfection, safe water storage, and behavioral change, have been widely field-tested. These options target the most affected, enhance health, contribute to development and productivity, and merit far greater priority for rapid implementation. PMID:11574307

  18. Detection of Anomalous Insiders in Collaborative Environments via Relational Analysis of Access Logs

    PubMed Central

    Chen, You; Malin, Bradley

    2014-01-01

    Collaborative information systems (CIS) are deployed within a diverse array of environments, ranging from the Internet to intelligence agencies to healthcare. It is increasingly the case that such systems are applied to manage sensitive information, making them targets for malicious insiders. While sophisticated security mechanisms have been developed to detect insider threats in various file systems, they are neither designed to model nor to monitor collaborative environments in which users function in dynamic teams with complex behavior. In this paper, we introduce a community-based anomaly detection system (CADS), an unsupervised learning framework to detect insider threats based on information recorded in the access logs of collaborative environments. CADS is based on the observation that typical users tend to form community structures, such that users with low a nity to such communities are indicative of anomalous and potentially illicit behavior. The model consists of two primary components: relational pattern extraction and anomaly detection. For relational pattern extraction, CADS infers community structures from CIS access logs, and subsequently derives communities, which serve as the CADS pattern core. CADS then uses a formal statistical model to measure the deviation of users from the inferred communities to predict which users are anomalies. To empirically evaluate the threat detection model, we perform an analysis with six months of access logs from a real electronic health record system in a large medical center, as well as a publicly-available dataset for replication purposes. The results illustrate that CADS can distinguish simulated anomalous users in the context of real user behavior with a high degree of certainty and with significant performance gains in comparison to several competing anomaly detection models. PMID:25485309

  19. Detection of Anomalous Insiders in Collaborative Environments via Relational Analysis of Access Logs.

    PubMed

    Chen, You; Malin, Bradley

    2011-01-01

    Collaborative information systems (CIS) are deployed within a diverse array of environments, ranging from the Internet to intelligence agencies to healthcare. It is increasingly the case that such systems are applied to manage sensitive information, making them targets for malicious insiders. While sophisticated security mechanisms have been developed to detect insider threats in various file systems, they are neither designed to model nor to monitor collaborative environments in which users function in dynamic teams with complex behavior. In this paper, we introduce a community-based anomaly detection system (CADS), an unsupervised learning framework to detect insider threats based on information recorded in the access logs of collaborative environments. CADS is based on the observation that typical users tend to form community structures, such that users with low a nity to such communities are indicative of anomalous and potentially illicit behavior. The model consists of two primary components: relational pattern extraction and anomaly detection. For relational pattern extraction, CADS infers community structures from CIS access logs, and subsequently derives communities, which serve as the CADS pattern core. CADS then uses a formal statistical model to measure the deviation of users from the inferred communities to predict which users are anomalies. To empirically evaluate the threat detection model, we perform an analysis with six months of access logs from a real electronic health record system in a large medical center, as well as a publicly-available dataset for replication purposes. The results illustrate that CADS can distinguish simulated anomalous users in the context of real user behavior with a high degree of certainty and with significant performance gains in comparison to several competing anomaly detection models.

  20. Metal-oxide-metal point contact junction detectors. [detection mechanism and mechanical stability

    NASA Technical Reports Server (NTRS)

    Baird, J.; Havemann, R. H.; Fults, R. D.

    1973-01-01

    The detection mechanism(s) and design of a mechanically stable metal-oxide-metal point contact junction detector are considered. A prototype for a mechanically stable device has been constructed and tested. A technique has been developed which accurately predicts microwave video detector and heterodyne mixer SIM (semiconductor-insulator-metal) diode performance from low dc frequency volt-ampere curves. The difference in contact potential between the two metals and geometrically induced rectification constitute the detection mechanisms.

  1. Identifying localized changes in large systems: Change-point detection for biomolecular simulations.

    PubMed

    Fan, Zhou; Dror, Ron O; Mildorf, Thomas J; Piana, Stefano; Shaw, David E

    2015-06-16

    Research on change-point detection, the classical problem of detecting abrupt changes in sequential data, has focused predominantly on datasets with a single observable. A growing number of time series datasets, however, involve many observables, often with the property that a given change typically affects only a few of the observables. We introduce a general statistical method that, given many noisy observables, detects points in time at which various subsets of the observables exhibit simultaneous changes in data distribution and explicitly identifies those subsets. Our work is motivated by the problem of identifying the nature and timing of biologically interesting conformational changes that occur during atomic-level simulations of biomolecules such as proteins. This problem has proved challenging both because each such conformational change might involve only a small region of the molecule and because these changes are often subtle relative to the ever-present background of faster structural fluctuations. We show that our method is effective in detecting biologically interesting conformational changes in molecular dynamics simulations of both folded and unfolded proteins, even in cases where these changes are difficult to detect using alternative techniques. This method may also facilitate the detection of change points in other types of sequential data involving large numbers of observables--a problem likely to become increasingly important as such data continue to proliferate in a variety of application domains.

  2. Multi-point laser coherent detection system and its application on vibration measurement

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Yang, C.; Xu, Y. J.; Liu, H.; Yan, K.; Guo, M.

    2015-05-01

    Laser Doppler vibrometry (LDV) is a well-known interferometric technique to measure the motions, vibrations and mode shapes of machine components and structures. The drawback of commercial LDV is that it can only offer a pointwise measurement. In order to build up a vibrometric image, a scanning device is normally adopted to scan the laser point in two spatial axes. These scanning laser Doppler vibrometers (SLDV) assume that the measurement conditions remain invariant while multiple and identical, sequential measurements are performed. This assumption makes SLDVs impractical to do measurement on transient events. In this paper, we introduce a new multiple-point laser coherent detection system based on spatial-encoding technology and fiber configuration. A simultaneous vibration measurement on multiple points is realized using a single photodetector. A prototype16-point laser coherent detection system is built and it is applied to measure the vibration of various objects, such as body of a car or a motorcycle when engine is on and under shock tests. The results show the prospect of multi-point laser coherent detection system in the area of nondestructive test and precise dynamic measurement.

  3. Using statistical and machine learning to help institutions detect suspicious access to electronic health records

    PubMed Central

    Kim, Jihoon; Grillo, Janice M; Ohno-Machado, Lucila

    2011-01-01

    Objective To determine whether statistical and machine-learning methods, when applied to electronic health record (EHR) access data, could help identify suspicious (ie, potentially inappropriate) access to EHRs. Methods From EHR access logs and other organizational data collected over a 2-month period, the authors extracted 26 features likely to be useful in detecting suspicious accesses. Selected events were marked as either suspicious or appropriate by privacy officers, and served as the gold standard set for model evaluation. The authors trained logistic regression (LR) and support vector machine (SVM) models on 10-fold cross-validation sets of 1291 labeled events. The authors evaluated the sensitivity of final models on an external set of 58 events that were identified as truly inappropriate and investigated independently from this study using standard operating procedures. Results The area under the receiver operating characteristic curve of the models on the whole data set of 1291 events was 0.91 for LR, and 0.95 for SVM. The sensitivity of the baseline model on this set was 0.8. When the final models were evaluated on the set of 58 investigated events, all of which were determined as truly inappropriate, the sensitivity was 0 for the baseline method, 0.76 for LR, and 0.79 for SVM. Limitations The LR and SVM models may not generalize because of interinstitutional differences in organizational structures, applications, and workflows. Nevertheless, our approach for constructing the models using statistical and machine-learning techniques can be generalized. An important limitation is the relatively small sample used for the training set due to the effort required for its construction. Conclusion The results suggest that statistical and machine-learning methods can play an important role in helping privacy officers detect suspicious accesses to EHRs. PMID:21672912

  4. 16 CFR Figure 5 to Subpart A of... - Zero Reference Point Related to Detecting Plane

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Zero Reference Point Related to Detecting Plane 5 Figure 5 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard Pt. 1209, Subpt. A, Fig. 5 Figure 5 to Subpart A...

  5. Emergency Point-of-Care Ultrasound Detection of Papilledema in the Pediatric Emergency Department.

    PubMed

    Ben-Yakov, Maxim; Desjardins, Marie-Pier; Fischer, Jason W J

    2015-11-01

    The application of emergency point-of-care ultrasound has been expanding in pediatric emergency medicine for a decade. In this case series, we describe the detection of papilledema in patients presenting to the pediatric emergency department using this technology and its potential impact on their clinical care. PMID:26535499

  6. 16 CFR Figure 5 to Subpart A of... - Zero Reference Point Related to Detecting Plane

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Zero Reference Point Related to Detecting Plane 5 Figure 5 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard...

  7. 16 CFR Figure 5 to Subpart A of... - Zero Reference Point Related to Detecting Plane

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Zero Reference Point Related to Detecting Plane 5 Figure 5 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard...

  8. 16 CFR Figure 5 to Subpart A of... - Zero Reference Point Related to Detecting Plane

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Zero Reference Point Related to Detecting Plane 5 Figure 5 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard...

  9. 16 CFR Figure 5 to Subpart A of... - Zero Reference Point Related to Detecting Plane

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Zero Reference Point Related to Detecting Plane 5 Figure 5 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard...

  10. Structure Line Detection from LIDAR Point Clouds Using Topological Elevation Analysis

    NASA Astrophysics Data System (ADS)

    Lo, C. Y.; Chen, L. C.

    2012-07-01

    Airborne LIDAR point clouds, which have considerable points on object surfaces, are essential to building modeling. In the last two decades, studies have developed different approaches to identify structure lines using two main approaches, data-driven and modeldriven. These studies have shown that automatic modeling processes depend on certain considerations, such as used thresholds, initial value, designed formulas, and predefined cues. Following the development of laser scanning systems, scanning rates have increased and can provide point clouds with higher point density. Therefore, this study proposes using topological elevation analysis (TEA) to detect structure lines instead of threshold-dependent concepts and predefined constraints. This analysis contains two parts: data pre-processing and structure line detection. To preserve the original elevation information, a pseudo-grid for generating digital surface models is produced during the first part. The highest point in each grid is set as the elevation value, and its original threedimensional position is preserved. In the second part, using TEA, the structure lines are identified based on the topology of local elevation changes in two directions. Because structure lines can contain certain geometric properties, their locations have small relieves in the radial direction and steep elevation changes in the circular direction. Following the proposed approach, TEA can be used to determine 3D line information without selecting thresholds. For validation, the TEA results are compared with those of the region growing approach. The results indicate that the proposed method can produce structure lines using dense point clouds.

  11. Road traffic sign detection and classification from mobile LiDAR point clouds

    NASA Astrophysics Data System (ADS)

    Weng, Shengxia; Li, Jonathan; Chen, Yiping; Wang, Cheng

    2016-03-01

    Traffic signs are important roadway assets that provide valuable information of the road for drivers to make safer and easier driving behaviors. Due to the development of mobile mapping systems that can efficiently acquire dense point clouds along the road, automated detection and recognition of road assets has been an important research issue. This paper deals with the detection and classification of traffic signs in outdoor environments using mobile light detection and ranging (Li- DAR) and inertial navigation technologies. The proposed method contains two main steps. It starts with an initial detection of traffic signs based on the intensity attributes of point clouds, as the traffic signs are always painted with highly reflective materials. Then, the classification of traffic signs is achieved based on the geometric shape and the pairwise 3D shape context. Some results and performance analyses are provided to show the effectiveness and limits of the proposed method. The experimental results demonstrate the feasibility and effectiveness of the proposed method in detecting and classifying traffic signs from mobile LiDAR point clouds.

  12. Sensitive detection of point mutation by electrochemiluminescence and DNA ligase-based assay

    NASA Astrophysics Data System (ADS)

    Zhou, Huijuan; Wu, Baoyan

    2008-12-01

    The technology of single-base mutation detection plays an increasingly important role in diagnosis and prognosis of genetic-based diseases. Here we reported a new method for the analysis of point mutations in genomic DNA through the integration of allele-specific oligonucleotide ligation assay (OLA) with magnetic beads-based electrochemiluminescence (ECL) detection scheme. In this assay the tris(bipyridine) ruthenium (TBR) labeled probe and the biotinylated probe are designed to perfectly complementary to the mutant target, thus a ligation can be generated between those two probes by Taq DNA Ligase in the presence of mutant target. If there is an allele mismatch, the ligation does not take place. The ligation products are then captured onto streptavidin-coated paramagnetic beads, and detected by measuring the ECL signal of the TBR label. Results showed that the new method held a low detection limit down to 10 fmol and was successfully applied in the identification of point mutations from ASTC-α-1, PANC-1 and normal cell lines in codon 273 of TP53 oncogene. In summary, this method provides a sensitive, cost-effective and easy operation approach for point mutation detection.

  13. An ECL-PCR method for quantitative detection of point mutation

    NASA Astrophysics Data System (ADS)

    Zhu, Debin; Xing, Da; Shen, Xingyan; Chen, Qun; Liu, Jinfeng

    2005-04-01

    A new method for identification of point mutations was proposed. Polymerase chain reaction (PCR) amplification of a sequence from genomic DNA was followed by digestion with a kind of restriction enzyme, which only cut the wild-type amplicon containing its recognition site. Reaction products were detected by electrochemiluminescence (ECL) assay after adsorption of the resulting DNA duplexes to the solid phase. One strand of PCR products carries biotin to be bound on a streptavidin-coated microbead for sample selection. Another strand carries Ru(bpy)32+ (TBR) to react with tripropylamine (TPA) to emit light for ECL detection. The method was applied to detect a specific point mutation in H-ras oncogene in T24 cell line. The results show that the detection limit for H-ras amplicon is 100 fmol and the linear range is more than 3 orders of magnitude, thus, make quantitative analysis possible. The genotype can be clearly discriminated. Results of the study suggest that ECL-PCR is a feasible quantitative method for safe, sensitive and rapid detection of point mutation in human genes.

  14. Staircase-scene-based nonuniformity correction in aerial point target detection systems.

    PubMed

    Huo, Lijun; Zhou, Dabiao; Wang, Dejiang; Liu, Rang; He, Bin

    2016-09-01

    Focal-plane arrays (FPAs) are often interfered by heavy fixed-pattern noise, which severely degrades the detection rate and increases the false alarms in airborne point target detection systems. Thus, high-precision nonuniformity correction is an essential preprocessing step. In this paper, a new nonuniformity correction method is proposed based on a staircase scene. This correction method can compensate for the nonlinear response of the detector and calibrate the entire optical system with computational efficiency and implementation simplicity. Then, a proof-of-concept point target detection system is established with a long-wave Sofradir FPA. Finally, the local standard deviation of the corrected image and the signal-to-clutter ratio of the Airy disk of a Boeing B738 are measured to evaluate the performance of the proposed nonuniformity correction method. Our experimental results demonstrate that the proposed correction method achieves high-quality corrections. PMID:27607295

  15. 3D change detection at street level using mobile laser scanning point clouds and terrestrial images

    NASA Astrophysics Data System (ADS)

    Qin, Rongjun; Gruen, Armin

    2014-04-01

    Automatic change detection and geo-database updating in the urban environment are difficult tasks. There has been much research on detecting changes with satellite and aerial images, but studies have rarely been performed at the street level, which is complex in its 3D geometry. Contemporary geo-databases include 3D street-level objects, which demand frequent data updating. Terrestrial images provides rich texture information for change detection, but the change detection with terrestrial images from different epochs sometimes faces problems with illumination changes, perspective distortions and unreliable 3D geometry caused by the lack of performance of automatic image matchers, while mobile laser scanning (MLS) data acquired from different epochs provides accurate 3D geometry for change detection, but is very expensive for periodical acquisition. This paper proposes a new method for change detection at street level by using combination of MLS point clouds and terrestrial images: the accurate but expensive MLS data acquired from an early epoch serves as the reference, and terrestrial images or photogrammetric images captured from an image-based mobile mapping system (MMS) at a later epoch are used to detect the geometrical changes between different epochs. The method will automatically mark the possible changes in each view, which provides a cost-efficient method for frequent data updating. The methodology is divided into several steps. In the first step, the point clouds are recorded by the MLS system and processed, with data cleaned and classified by semi-automatic means. In the second step, terrestrial images or mobile mapping images at a later epoch are taken and registered to the point cloud, and then point clouds are projected on each image by a weighted window based z-buffering method for view dependent 2D triangulation. In the next step, stereo pairs of the terrestrial images are rectified and re-projected between each other to check the geometrical

  16. A miniaturised image based fluorescence detection system for point-of-care-testing of cocaine abuse

    NASA Astrophysics Data System (ADS)

    Walczak, Rafał; Krüger, Jan; Moynihan, Shane

    2015-08-01

    In this paper, we describe a miniaturised image-based fluorescence detection system and demonstrate its viability as a highly sensitive tool for point-of-care-analysis of drugs of abuse in human sweat with a focus on monitor individuals for drugs of abuse. Investigations of miniaturised and low power optoelectronic configurations and methodologies for real-time image analysis were successfully carried out. The miniaturised fluorescence detection system was validated against a reference detection system under controlled laboratory conditions by analysing spiked sweat samples in dip stick and then strip with sample pad. As a result of the validation studies, a 1 ng mL-1 limit of detection of cocaine in sweat and full agreement of test results with the reference detection system can be reported. Results of the investigations open the way towards a detection system that integrates a hand-held fluorescence reader and a wearable skinpatch, and which can collect and in situ analyse sweat for the presence of cocaine at any point for up to tenths hours.

  17. Maximizing detection probability of Wetland-dependent birds during point-count surveys in northwestern Florida

    USGS Publications Warehouse

    Nadeau, C.P.; Conway, C.J.; Smith, B.S.; Lewis, T.E.

    2008-01-01

    We conducted 262 call-broadcast point-count surveys (1-6 replicate surveys on each of 62 points) using standardized North American Marsh Bird Monitoring Protocols between 31 May and 7 July 2006 on St. Vincent National Wildlife Refuge, an island off the northwest coast of Florida. We conducted double-blind multiple-observer surveys, paired morning and evening surveys, and paired morning and night surveys to examine the influence of call-broadcast and time of day on detection probability. Observer detection probability for all species pooled was 75% and was similar between passive (69%) and call-broadcast (65%) periods. Detection probability was higher on morning than evening (t = 3.0, P = 0.030) or night (t = 3.4, P = 0.042) surveys when we pooled all species. Detection probability was higher (but not significant for all species) on morning compared to evening or night surveys for all five focal species detected on surveys: Least Bittern (Ixobrychus exilis), Clapper Rail (Rallus longirostris), Purple Gallinule (Porphyrula martinica), Common Moorhen (Gallinula chloropus), and American Coot (Fulica americana). We detected more Least Bitterns (t = 2.4, P = 0.064) and Common Moorhens (t = 2.8, P = 0.026) on morning than evening surveys, and more Clapper Rails (t = 5.1, P = 0.014) on morning than night surveys.

  18. Comparison of point counts and territory mapping for detecting effects of forest management on songbirds

    USGS Publications Warehouse

    Newell, Felicity L.; Sheehan, James; Wood, Petra Bohall; Rodewald, Amanda D.; Buehler, David A.; Keyser, Patrick D.; Larkin, Jeffrey L.; Beachy, Tiffany A.; Bakermans, Marja H.; Boves, Than J.; Evans, Andrea; George, Gregory A.; McDermott, Molly E.; Perkins, Kelly A.; White, Matthew; Wigley, T. Bently

    2013-01-01

    Point counts are commonly used to assess changes in bird abundance, including analytical approaches such as distance sampling that estimate density. Point-count methods have come under increasing scrutiny because effects of detection probability and field error are difficult to quantify. For seven forest songbirds, we compared fixed-radii counts (50 m and 100 m) and density estimates obtained from distance sampling to known numbers of birds determined by territory mapping. We applied point-count analytic approaches to a typical forest management question and compared results to those obtained by territory mapping. We used a before–after control impact (BACI) analysis with a data set collected across seven study areas in the central Appalachians from 2006 to 2010. Using a 50-m fixed radius, variance in error was at least 1.5 times that of the other methods, whereas a 100-m fixed radius underestimated actual density by >3 territories per 10 ha for the most abundant species. Distance sampling improved accuracy and precision compared to fixed-radius counts, although estimates were affected by birds counted outside 10-ha units. In the BACI analysis, territory mapping detected an overall treatment effect for five of the seven species, and effects were generally consistent each year. In contrast, all point-count methods failed to detect two treatment effects due to variance and error in annual estimates. Overall, our results highlight the need for adequate sample sizes to reduce variance, and skilled observers to reduce the level of error in point-count data. Ultimately, the advantages and disadvantages of different survey methods should be considered in the context of overall study design and objectives, allowing for trade-offs among effort, accuracy, and power to detect treatment effects.

  19. Integrated electrochemical microsystems for genetic detection of pathogens at the point of care.

    PubMed

    Hsieh, Kuangwen; Ferguson, B Scott; Eisenstein, Michael; Plaxco, Kevin W; Soh, H Tom

    2015-04-21

    The capacity to achieve rapid, sensitive, specific, quantitative, and multiplexed genetic detection of pathogens via a robust, portable, point-of-care platform could transform many diagnostic applications. And while contemporary technologies have yet to effectively achieve this goal, the advent of microfluidics provides a potentially viable approach to this end by enabling the integration of sophisticated multistep biochemical assays (e.g., sample preparation, genetic amplification, and quantitative detection) in a monolithic, portable device from relatively small biological samples. Integrated electrochemical sensors offer a particularly promising solution to genetic detection because they do not require optical instrumentation and are readily compatible with both integrated circuit and microfluidic technologies. Nevertheless, the development of generalizable microfluidic electrochemical platforms that integrate sample preparation and amplification as well as quantitative and multiplexed detection remains a challenging and unsolved technical problem. Recognizing this unmet need, we have developed a series of microfluidic electrochemical DNA sensors that have progressively evolved to encompass each of these critical functionalities. For DNA detection, our platforms employ label-free, single-step, and sequence-specific electrochemical DNA (E-DNA) sensors, in which an electrode-bound, redox-reporter-modified DNA "probe" generates a current change after undergoing a hybridization-induced conformational change. After successfully integrating E-DNA sensors into a microfluidic chip format, we subsequently incorporated on-chip genetic amplification techniques including polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) to enable genetic detection at clinically relevant target concentrations. To maximize the potential point-of-care utility of our platforms, we have further integrated sample preparation via immunomagnetic separation, which

  20. Development of Advanced Electrochemical Sensors for DNA Detection at the Point of Care

    NASA Astrophysics Data System (ADS)

    Hsieh, Kuangwen

    In the post-genomic era, ever-advancing capabilities in DNA detection and analysis have become vital to the detection of infectious diseases and the diagnosis of genetic abnormalities and inheritable diseases. The benefit of such capabilities, however, has yet to reach patients outside of centralized facilities. There thus exists an increasing need to decentralize DNA detection methods and to administer such diagnostics at the "point of care." Electrochemical-based DNA sensors present a compelling approach, but have yet to deliver satisfactory sensitivity, specificity, miniaturization, and real-time monitoring capability to meet the demand of point-of-care diagnostics. Motivated by their potential and their current limitations, in this dissertation, we present a series of strategies that we have undertaken in order to address the key shortcomings of electrochemical DNA sensors and advance them toward point-of-care applications. First, we report a single-step, single reagent, label-free, isothermal electrochemical DNA sensor based on the phenomenon of enzyme catalyzed target recycling amplification. Using this technique, we achieve improved detection limit in comparison to hybridization-based sensors without amplification. We also demonstrate greater than 16-fold amplification of signal at low target concentrations. Next, we present a novel electrochemical DNA sensor that detects single-nucleotide mismatched targets with unprecedented "polarity-switching" responses. This "bipolar" sensor employs a surface-bound and redox-modified (methylene blue) DNA probe architecture, and outputs a decreased Faradaic current when hybridized to a perfectly matched (PM) target, but conversely reports an increased Faradaic current when hybridized to a single-base mismatched (SM) target. Third, we describe the microfluidic electrochemical dynamic allele specific hybridization (microE-DASH) platform for versatile and rapid detection of single-nucleotide polymorphisms. Implementing

  1. Landmine detection with Bayesian cross-categorization on point-wise, contextual and spatial features

    NASA Astrophysics Data System (ADS)

    Léveillé, Jasmin; Yu, Ssu-Hsin; Gandhe, Avinash

    2016-05-01

    Recently developed feature extraction methods proposed in the explosive hazard detection community have yielded many features that potentially provide complementary information for explosive detection. Finding the right combination of features that is most effective in distinguishing targets from clutter, on the other hand, is extremely challenging due to a large number of potential features to explore. Furthermore, sensors employed for mine and buried explosive hazard detection are typically sensitive to environmental conditions such as soil properties and weather as well as other operating parameters. In this work, we applied Bayesian cross-categorization (CrossCat) to a heterogeneous set of features derived from electromagnetic induction (EMI) sensor time-series for purposes of buried explosive hazard detection. The set of features used here includes simple, point-wise measurements such as the overall magnitude of the EMI response, contextual information such as soil type, and a new feature consisting of spatially aggregated Discrete Spectra of Relaxation Frequencies (DSRFs). Previous work showed that the DSRF characterizes target properties with some invariance to orientation and position. We have developed a novel approach to aggregate point-wise DSRF estimates. The spatial aggregation is based on the Bag-of-Words (BoW) model found in the machine learning and computer vision literatures and aims to enhance the invariance properties of point-wise DSRF estimates. We considered various refinements to the BoW model for purpose of buried explosive hazard detection and tested their usefulness as part of a Bayesian cross-categorization framework on data collected from two different sites. The results show improved performance over classifiers using only point-wise features.

  2. Detecting Long-term Changes in Point Source Fossil CO2 Emissions with Tree Ring Archives

    NASA Astrophysics Data System (ADS)

    Keller, E. D.; Turnbull, J. C.; Norris, M. W.

    2015-12-01

    We examine the utility of tree ring 14C archives for detecting long term changes in fossil CO2 emissions from a point source. Trees assimilate carbon from the atmosphere during photosynthesis, in the process faithfully recording the average atmospheric 14C content over the growing season in each annual tree ring. Using 14C as a proxy for fossil CO2, we examine interannual variability over six years of fossil CO2 observations between 2004 and 2012 from two trees growing near the Kapuni Natural Gas Plant in rural Taranaki, New Zealand. We quantify the amount of variability that can be attributed to transport and meteorology by simulating constant point source fossil CO2 emissions over the observation period with the atmospheric transport model WindTrax. We then calculate the amount of change in emissions that we can detect with new observations over annual or multi-year time periods given both measurement uncertainty of 1ppm and the modelled variation in transport. In particular, we ask, what is the minimum amount of change in emissions that we can detect using this method, given a reference period of six years? We find that changes of 42% or more could be detected in a new sample from one year at the pine tree, or 22% in the case of four years of new samples. This threshold lowers and the method becomes more practical with a larger signal; for point sources 10 times the magnitude of the Kapuni plant (a typical size for large electricity generation point sources worldwide), it would be possible to detect sustained emissions changes on the order of 10% given suitable meteorology and observations.

  3. Effects of point-loss punishers on human signal-detection performance.

    PubMed

    Lie, Celia; Alsop, Brent

    2009-07-01

    Three experiments using human participants varied the distribution of point-gain reinforcers or point-loss punishers in two-alternative signal-detection procedures. Experiment 1 varied the distribution of point-gain reinforcers for correct responses (Group A) and point-loss punishers for errors (Group B) across conditions. Response bias varied systematically as a function of the relative reinforcer or punisher frequencies. Experiment 2 arranged two conditions - one where an unequal ratio of reinforcement (5ratio1 or 1ratio5) was presented without punishment (R-only), and another where the same reinforcer ratio was presented with an equal distribution of point-loss punishers (R+P). Response bias was significantly greater in the R-only condition than the R+P condition, supporting a subtractive model of punishment. Experiment 3 varied the distribution of point-gain reinforcers for correct responses across four unequal reinforcer ratios (5ratio1, 2ratio1, 1ratio2, 1ratio5) both without (R-only) and with (R+P) an equal distribution of point-loss punishers for errors. Response bias varied systematically with changes in relative reinforcer frequency for both R-only and R+P conditions, with 5 out of 8 participants showing increases in sensitivity estimates from R-only to R+P conditions. Overall, the results indicated that punishers have similar but opposite effects to reinforcers in detection procedures and that combined reinforcer and punisher effects might be better modeled by a subtractive punishment model than an additive punishment model, consistent with research using concurrent-schedule choice procedures. PMID:20119520

  4. Nanoparticle Detection of Urinary Markers for Point-of-Care Diagnosis of Kidney Injury.

    PubMed

    Chung, Hyun Jung; Pellegrini, Kathryn L; Chung, Jaehoon; Wanigasuriya, Kamani; Jayawardene, Innocent; Lee, Kyungheon; Lee, Hakho; Vaidya, Vishal S; Weissleder, Ralph

    2015-01-01

    The high incidence of acute and chronic kidney injury due to various environmental factors such as heavy metals or chemicals has been a major problem in developing countries. However, the diagnosis of kidney injury in these areas can be more challenging due to the lack of highly sensitive and specific techniques that can be applied in point-of-care settings. To address this, we have developed a technique called 'micro-urine nanoparticle detection (μUNPD)', that allows the detection of trace amounts of molecular markers in urine. Specifically, this technique utilizes an automated on-chip assay followed by detection with a hand-held device for the read-out. Using the μUNPD technology, the kidney injury markers KIM-1 and Cystatin C were detected down to concentrations of 0.1 ng/ml and 20 ng/ml respectively, which meets the cut-off range required to identify patients with acute or chronic kidney injury. Thus, we show that the μUNPD technology enables point of care and non-invasive detection of kidney injury, and has potential for applications in diagnosing kidney injury with high sensitivity in resource-limited settings. PMID:26186708

  5. Measurement of biomarker proteins for point-of-care early detection and monitoring of cancer

    PubMed Central

    Kumar, Challa V.; Gutkind, J. Silvio; Patel, Vyomesh

    2010-01-01

    This critical review evaluates progress toward viable point-of-care protein biomarker measurements for cancer detection and diagnostics. The ability to measure panels of specific, selective cancer biomarker proteins in physicians’ surgeries and clinics has the potential to revolutionize cancer detection, monitoring, and therapy. The dream envisions reliable, cheap, automated, technically undemanding devices that can analyze a patient’s serum or saliva in a clinical setting, allowing on-the-spot diagnosis. Existing commercial products for protein assays are reliable in laboratory settings, but have limitations for point-of-care applications. A number of ultrasensitive immunosensors and some arrays have been developed, many based on nanotechnology. Multilabel detection coupled with high capture molecule density in immunosensors and arrays seems to be capable of detecting a wide range of protein concentrations with sensitivity ranging into the sub pg mL−1 level. Multilabel arrays can be designed to detect both high and ultralow abundance proteins in the same sample. However, only a few of the newer ultrasensitive methods have been evaluated with real patient samples, which is key to establishing clinical sensitivity and selectivity. PMID:20614087

  6. Nanoparticle Detection of Urinary Markers for Point-of-Care Diagnosis of Kidney Injury

    PubMed Central

    Wanigasuriya, Kamani; Jayawardene, Innocent; Lee, Kyungheon; Lee, Hakho; Vaidya, Vishal S.; Weissleder, Ralph

    2015-01-01

    The high incidence of acute and chronic kidney injury due to various environmental factors such as heavy metals or chemicals has been a major problem in developing countries. However, the diagnosis of kidney injury in these areas can be more challenging due to the lack of highly sensitive and specific techniques that can be applied in point-of-care settings. To address this, we have developed a technique called ‘micro-urine nanoparticle detection (μUNPD)’, that allows the detection of trace amounts of molecular markers in urine. Specifically, this technique utilizes an automated on-chip assay followed by detection with a hand-held device for the read-out. Using the μUNPD technology, the kidney injury markers KIM-1 and Cystatin C were detected down to concentrations of 0.1 ng/ml and 20 ng/ml respectively, which meets the cut-off range required to identify patients with acute or chronic kidney injury. Thus, we show that the μUNPD technology enables point of care and non-invasive detection of kidney injury, and has potential for applications in diagnosing kidney injury with high sensitivity in resource-limited settings. PMID:26186708

  7. Weighted Change-Point Method for Detecting Differential Gene Expression in Breast Cancer Microarray Data

    PubMed Central

    Wang, Yao; Sun, Guang; Ji, Zhaohua; Xing, Chong; Liang, Yanchun

    2012-01-01

    In previous work, we proposed a method for detecting differential gene expression based on change-point of expression profile. This non-parametric change-point method gave promising result in both simulation study and public dataset experiment. However, the performance is still limited by the less sensitiveness to the right bound and the statistical significance of the statistics has not been fully explored. To overcome the insensitiveness to the right bound we modified the original method by adding a weight function to the Dn statistic. Simulation study showed that the weighted change-point statistics method is significantly better than the original NPCPS in terms of ROC, false positive rate, as well as change-point estimate. The mean absolute error of the estimated change-point by weighted change-point method was 0.03, reduced by more than 50% comparing with the original 0.06, and the mean FPR was reduced by more than 55%. Experiment on microarray Dataset I resulted in 3974 differentially expressed genes out of total 5293 genes; experiment on microarray Dataset II resulted in 9983 differentially expressed genes among total 12576 genes. In summary, the method proposed here is an effective modification to the previous method especially when only a small subset of cancer samples has DGE. PMID:22276133

  8. A hybrid algorithm for multiple change-point detection in continuous measurements

    NASA Astrophysics Data System (ADS)

    Priyadarshana, W. J. R. M.; Polushina, T.; Sofronov, G.

    2013-10-01

    Array comparative genomic hybridization (aCGH) is one of the techniques that can be used to detect copy number variations in DNA sequences. It has been identified that abrupt changes in the human genome play a vital role in the progression and development of many diseases. We propose a hybrid algorithm that utilizes both the sequential techniques and the Cross-Entropy method to estimate the number of change points as well as their locations in aCGH data. We applied the proposed hybrid algorithm to both artificially generated data and real data to illustrate the usefulness of the methodology. Our results show that the proposed algorithm is an effective method to detect multiple change-points in continuous measurements.

  9. On the Choice of Access Point Selection Criterion and Other Position Estimation Characteristics for WLAN-Based Indoor Positioning.

    PubMed

    Laitinen, Elina; Lohan, Elena Simona

    2016-01-01

    The positioning based on Wireless Local Area Networks (WLAN) is one of the most promising technologies for indoor location-based services, generally using the information carried by Received Signal Strengths (RSS). One challenge, however, is the huge amount of data in the radiomap database due to the enormous number of hearable Access Points (AP) that could make the positioning system very complex. This paper concentrates on WLAN-based indoor location by comparing fingerprinting, path loss and weighted centroid based positioning approaches in terms of complexity and performance and studying the effects of grid size and AP reduction with several choices for appropriate selection criterion. All results are based on real field measurements in three multi-floor buildings. We validate our earlier findings concerning several different AP selection criteria and conclude that the best results are obtained with a maximum RSS-based criterion, which also proved to be the most consistent among the different investigated approaches. We show that the weighted centroid based low-complexity method is very sensitive to AP reduction, while the path loss-based method is also very robust to high percentage removals. Indeed, for fingerprinting, 50% of the APs can be removed safely with a properly chosen removal criterion without increasing the positioning error much. PMID:27213395

  10. On the Choice of Access Point Selection Criterion and Other Position Estimation Characteristics for WLAN-Based Indoor Positioning

    PubMed Central

    Laitinen, Elina; Lohan, Elena Simona

    2016-01-01

    The positioning based on Wireless Local Area Networks (WLAN) is one of the most promising technologies for indoor location-based services, generally using the information carried by Received Signal Strengths (RSS). One challenge, however, is the huge amount of data in the radiomap database due to the enormous number of hearable Access Points (AP) that could make the positioning system very complex. This paper concentrates on WLAN-based indoor location by comparing fingerprinting, path loss and weighted centroid based positioning approaches in terms of complexity and performance and studying the effects of grid size and AP reduction with several choices for appropriate selection criterion. All results are based on real field measurements in three multi-floor buildings. We validate our earlier findings concerning several different AP selection criteria and conclude that the best results are obtained with a maximum RSS-based criterion, which also proved to be the most consistent among the different investigated approaches. We show that the weighted centroid based low-complexity method is very sensitive to AP reduction, while the path loss-based method is also very robust to high percentage removals. Indeed, for fingerprinting, 50% of the APs can be removed safely with a properly chosen removal criterion without increasing the positioning error much. PMID:27213395

  11. On the Choice of Access Point Selection Criterion and Other Position Estimation Characteristics for WLAN-Based Indoor Positioning.

    PubMed

    Laitinen, Elina; Lohan, Elena Simona

    2016-05-20

    The positioning based on Wireless Local Area Networks (WLAN) is one of the most promising technologies for indoor location-based services, generally using the information carried by Received Signal Strengths (RSS). One challenge, however, is the huge amount of data in the radiomap database due to the enormous number of hearable Access Points (AP) that could make the positioning system very complex. This paper concentrates on WLAN-based indoor location by comparing fingerprinting, path loss and weighted centroid based positioning approaches in terms of complexity and performance and studying the effects of grid size and AP reduction with several choices for appropriate selection criterion. All results are based on real field measurements in three multi-floor buildings. We validate our earlier findings concerning several different AP selection criteria and conclude that the best results are obtained with a maximum RSS-based criterion, which also proved to be the most consistent among the different investigated approaches. We show that the weighted centroid based low-complexity method is very sensitive to AP reduction, while the path loss-based method is also very robust to high percentage removals. Indeed, for fingerprinting, 50% of the APs can be removed safely with a properly chosen removal criterion without increasing the positioning error much.

  12. The resolution of point sources of light as analyzed by quantum detection theory

    NASA Technical Reports Server (NTRS)

    Helstrom, C. W.

    1972-01-01

    The resolvability of point sources of incoherent light is analyzed by quantum detection theory in terms of two hypothesis-testing problems. In the first, the observer must decide whether there are two sources of equal radiant power at given locations, or whether there is only one source of twice the power located midway between them. In the second problem, either one, but not both, of two point sources is radiating, and the observer must decide which it is. The decisions are based on optimum processing of the electromagnetic field at the aperture of an optical instrument. In both problems the density operators of the field under the two hypotheses do not commute. The error probabilities, determined as functions of the separation of the points and the mean number of received photons, characterize the ultimate resolvability of the sources.

  13. Resolution of point sources of light as analyzed by quantum detection theory.

    NASA Technical Reports Server (NTRS)

    Helstrom, C. W.

    1973-01-01

    The resolvability of point sources of incoherent thermal light is analyzed by quantum detection theory in terms of two hypothesis-testing problems. In the first, the observer must decide whether there are two sources of equal radiant power at given locations, or whether there is only one source of twice the power located midway between them. In the second problem, either one, but not both, of two point sources is radiating, and the observer must decide which it is. The decisions are based on optimum processing of the electromagnetic field at the aperture of an optical instrument. In both problems the density operators of the field under the two hypotheses do not commute. The error probabilities, determined as functions of the separation of the points and the mean number of received photons, characterize the ultimate resolvability of the sources.

  14. Change Detection from differential airborne LiDAR using a weighted Anisotropic Iterative Closest Point Algorithm

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Kusari, A.; Glennie, C. L.; Oskin, M. E.; Hinojosa-Corona, A.; Borsa, A. A.; Arrowsmith, R.

    2013-12-01

    Differential LiDAR (Light Detection and Ranging) from repeated surveys has recently emerged as an effective tool to measure three-dimensional (3D) change for applications such as quantifying slip and spatially distributed warping associated with earthquake ruptures, and examining the spatial distribution of beach erosion after hurricane impact. Currently, the primary method for determining 3D change is through the use of the iterative closest point (ICP) algorithm and its variants. However, all current studies using ICP have assumed that all LiDAR points in the compared point clouds have uniform accuracy. This assumption is simplistic given that the error for each LiDAR point is variable, and dependent upon highly variable factors such as target range, angle of incidence, and aircraft trajectory accuracy. Therefore, to rigorously determine spatial change, it would be ideal to model the random error for every LiDAR observation in the differential point cloud, and use these error estimates as apriori weights in the ICP algorithm. To test this approach, we implemented a rigorous LiDAR observation error propagation method to generate estimated random error for each point in a LiDAR point cloud, and then determine 3D displacements between two point clouds using an anistropic weighted ICP algorithm. The algorithm was evaluated by qualitatively and quantitatively comparing post earthquake slip estimates from the 2010 El Mayor-Cucapah Earthquake between a uniform weight and anistropically weighted ICP algorithm, using pre-event LiDAR collected in 2006 by Instituto Nacional de Estadística y Geografía (INEGI), and post-event LiDAR collected by The National Center for Airborne Laser Mapping (NCALM).

  15. Contrast Invariant Interest Point Detection by Zero-Norm LoG Filter.

    PubMed

    Zhenwei Miao; Xudong Jiang; Kim-Hui Yap

    2016-01-01

    The Laplacian of Gaussian (LoG) filter is widely used in interest point detection. However, low-contrast image structures, though stable and significant, are often submerged by the high-contrast ones in the response image of the LoG filter, and hence are difficult to be detected. To solve this problem, we derive a generalized LoG filter, and propose a zero-norm LoG filter. The response of the zero-norm LoG filter is proportional to the weighted number of bright/dark pixels in a local region, which makes this filter be invariant to the image contrast. Based on the zero-norm LoG filter, we develop an interest point detector to extract local structures from images. Compared with the contrast dependent detectors, such as the popular scale invariant feature transform detector, the proposed detector is robust to illumination changes and abrupt variations of images. Experiments on benchmark databases demonstrate the superior performance of the proposed zero-norm LoG detector in terms of the repeatability and matching score of the detected points as well as the image recognition rate under different conditions.

  16. Dynamic connectivity detection: an algorithm for determining functional connectivity change points in fMRI data.

    PubMed

    Xu, Yuting; Lindquist, Martin A

    2015-01-01

    Recently there has been an increased interest in using fMRI data to study the dynamic nature of brain connectivity. In this setting, the activity in a set of regions of interest (ROIs) is often modeled using a multivariate Gaussian distribution, with a mean vector and covariance matrix that are allowed to vary as the experiment progresses, representing changing brain states. In this work, we introduce the Dynamic Connectivity Detection (DCD) algorithm, which is a data-driven technique to detect temporal change points in functional connectivity, and estimate a graph between ROIs for data within each segment defined by the change points. DCD builds upon the framework of the recently developed Dynamic Connectivity Regression (DCR) algorithm, which has proven efficient at detecting changes in connectivity for problems consisting of a small to medium (< 50) number of regions, but which runs into computational problems as the number of regions becomes large (>100). The newly proposed DCD method is faster, requires less user input, and is better able to handle high-dimensional data. It overcomes the shortcomings of DCR by adopting a simplified sparse matrix estimation approach and a different hypothesis testing procedure to determine change points. The application of DCD to simulated data, as well as fMRI data, illustrates the efficacy of the proposed method.

  17. Method for detecting point mutations in DNA utilizing fluorescence energy transfer

    DOEpatents

    Parkhurst, Lawrence J.; Parkhurst, Kay M.; Middendorf, Lyle

    2001-01-01

    A method for detecting point mutations in DNA using a fluorescently labeled oligomeric probe and Forster resonance energy transfer (FRET) is disclosed. The selected probe is initially labeled at each end with a fluorescence dye, which act together as a donor/acceptor pair for FRET. The fluorescence emission from the dyes changes dramatically from the duplex stage, wherein the probe is hybridized to the complementary strand of DNA, to the single strand stage, when the probe is melted to become detached from the DNA. The change in fluorescence is caused by the dyes coming into closer proximity after melting occurs and the probe becomes detached from the DNA strand. The change in fluorescence emission as a function of temperature is used to calculate the melting temperature of the complex or T.sub.m. In the case where there is a base mismatch between the probe and the DNA strand, indicating a point mutation, the T.sub.m has been found to be significantly lower than the T.sub.m for a perfectly match probelstand duplex. The present invention allows for the detection of the existence and magnitude of T.sub.m, which allows for the quick and accurate detection of a point mutation in the DNA strand and, in some applications, the determination of the approximate location of the mutation within the sequence.

  18. Detection of fault structures with airborne LiDAR point-cloud data

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Du, Lei

    2015-08-01

    The airborne LiDAR (Light Detection And Ranging) technology is a new type of aerial earth observation method which can be used to produce high-precision DEM (Digital Elevation Model) quickly and reflect ground surface information directly. Fault structure is one of the key forms of crustal movement, and its quantitative description is the key to the research of crustal movement. The airborne LiDAR point-cloud data is used to detect and extract fault structures automatically based on linear extension, elevation mutation and slope abnormal characteristics. Firstly, the LiDAR point-cloud data is processed to filter out buildings, vegetation and other non-surface information with the TIN (Triangulated Irregular Network) filtering method and Burman model calibration method. TIN and DEM are made from the processed data sequentially. Secondly, linear fault structures are extracted based on dual-threshold method. Finally, high-precision DOM (Digital Orthophoto Map) and other geological knowledge are used to check the accuracy of fault structure extraction. An experiment is carried out in Beiya Village of Yunnan Province, China. With LiDAR technology, results reveal that: the airborne LiDAR point-cloud data can be utilized to extract linear fault structures accurately and automatically, measure information such as height, width and slope of fault structures with high precision, and detect faults in areas with vegetation coverage effectively.

  19. Fast and Robust Segmentation and Classification for Change Detection in Urban Point Clouds

    NASA Astrophysics Data System (ADS)

    Roynard, X.; Deschaud, J.-E.; Goulette, F.

    2016-06-01

    Change detection is an important issue in city monitoring to analyse street furniture, road works, car parking, etc. For example, parking surveys are needed but are currently a laborious task involving sending operators in the streets to identify the changes in car locations. In this paper, we propose a method that performs a fast and robust segmentation and classification of urban point clouds, that can be used for change detection. We apply this method to detect the cars, as a particular object class, in order to perform parking surveys automatically. A recently proposed method already addresses the need for fast segmentation and classification of urban point clouds, using elevation images. The interest to work on images is that processing is much faster, proven and robust. However there may be a loss of information in complex 3D cases: for example when objects are one above the other, typically a car under a tree or a pedestrian under a balcony. In this paper we propose a method that retain the three-dimensional information while preserving fast computation times and improving segmentation and classification accuracy. It is based on fast region-growing using an octree, for the segmentation, and specific descriptors with Random-Forest for the classification. Experiments have been performed on large urban point clouds acquired by Mobile Laser Scanning. They show that the method is as fast as the state of the art, and that it gives more robust results in the complex 3D cases.

  20. A quantitative strategy to detect changes in accessibility of protein regions to chemical modification on heterodimerization.

    PubMed

    Dreger, Mathias; Leung, Bo Wah; Brownlee, George G; Deng, Tao

    2009-07-01

    We describe a method for studying quantitative changes in accessibility of surface lysine residues of the PB1 subunit of the influenza RNA polymerase as a result of association with the PA subunit to form a PB1-PA heterodimer. Our method combines two established methods: (i) the chemical modification of surface lysine residues of native proteins by N-hydroxysuccinimidobiotin (NHS-biotin) and (ii) the stable isotope labeling of amino acids in cell culture (SILAC) followed by tryptic digestion and mass spectrometry. By linking the chemical modification with the SILAC methodology for the first time, we obtain quantitative data on chemical modification allowing subtle changes in accessibility to be described. Five regions in the PB1 monomer showed altered reactivity to NHS-biotin when compared with the [PB1-PA] heterodimer. Mutational analysis of residues in two such regions-at K265 and K481 of PB1, which were about three- and twofold, respectively, less accessible to biotinylation in the PB1-PA heterodimer compared with the PB1 monomer, demonstrated that both K265 and K481 were crucial for polymerase function. This novel assay of quantitative profiling of biotinylation patterns (Q-POP assay) highlights likely conformational changes at important functional sites, as observed here for PB1, and may provide information on protein-protein interaction interfaces. The Q-POP assay should be a generally applicable approach and may detect novel functional sites suitable for targeting by drugs. PMID:19517532

  1. A quantitative strategy to detect changes in accessibility of protein regions to chemical modification on heterodimerization

    PubMed Central

    Dreger, Mathias; Leung, Bo Wah; Brownlee, George G; Deng, Tao

    2009-01-01

    We describe a method for studying quantitative changes in accessibility of surface lysine residues of the PB1 subunit of the influenza RNA polymerase as a result of association with the PA subunit to form a PB1-PA heterodimer. Our method combines two established methods: (i) the chemical modification of surface lysine residues of native proteins by N-hydroxysuccinimidobiotin (NHS-biotin) and (ii) the stable isotope labeling of amino acids in cell culture (SILAC) followed by tryptic digestion and mass spectrometry. By linking the chemical modification with the SILAC methodology for the first time, we obtain quantitative data on chemical modification allowing subtle changes in accessibility to be described. Five regions in the PB1 monomer showed altered reactivity to NHS-biotin when compared with the [PB1-PA] heterodimer. Mutational analysis of residues in two such regions—at K265 and K481 of PB1, which were about three- and twofold, respectively, less accessible to biotinylation in the PB1-PA heterodimer compared with the PB1 monomer, demonstrated that both K265 and K481 were crucial for polymerase function. This novel assay of quantitative profiling of biotinylation patterns (Q-POP assay) highlights likely conformational changes at important functional sites, as observed here for PB1, and may provide information on protein–protein interaction interfaces. The Q-POP assay should be a generally applicable approach and may detect novel functional sites suitable for targeting by drugs. PMID:19517532

  2. Optical beat interference noise reduction in OFDMA optical access link using self-homodyne balanced detection

    NASA Astrophysics Data System (ADS)

    Jung, Sang-Min; Won, Yong-Yuk; Han, Sang-Kook

    2013-12-01

    A Novel technique for reducing the OBI noise in optical OFDMA-PON uplink is presented. OFDMA is a multipleaccess/ multiplexing scheme that can provide multiplexing operation of user data streams onto the downlink sub-channels and uplink multiple access by means of dividing OFDM subcarriers as sub-channels. The main issue of high-speed, single-wavelength upstream OFDMA-PON arises from optical beating interference noise. Because the sub-channels are allocated dynamically to multiple access users over same nominal wavelength, it generates the optical beating interference among upstream signals. In this paper, we proposed a novel scheme using self-homodyne balanced detection in the optical line terminal (OLT) to reduce OBI noise which is generated in the uplink transmission of OFDMA-PON system. When multiple OFDMA sub-channels over the same nominal wavelength are received at the same time in the proposed architecture, OBI noises can be removed using balanced detection. Using discrete multitone modulation (DMT) to generate real valued OFDM signals, the proposed technique is verified through experimental demonstration.

  3. Automated feature detection and identification in digital point-ordered signals

    DOEpatents

    Oppenlander, Jane E.; Loomis, Kent C.; Brudnoy, David M.; Levy, Arthur J.

    1998-01-01

    A computer-based automated method to detect and identify features in digital point-ordered signals. The method is used for processing of non-destructive test signals, such as eddy current signals obtained from calibration standards. The signals are first automatically processed to remove noise and to determine a baseline. Next, features are detected in the signals using mathematical morphology filters. Finally, verification of the features is made using an expert system of pattern recognition methods and geometric criteria. The method has the advantage that standard features can be, located without prior knowledge of the number or sequence of the features. Further advantages are that standard features can be differentiated from irrelevant signal features such as noise, and detected features are automatically verified by parameters extracted from the signals. The method proceeds fully automatically without initial operator set-up and without subjective operator feature judgement.

  4. Electrically detected nuclear magnetic resonance in GaAs/AlGaAs-based quantum point contacts

    NASA Astrophysics Data System (ADS)

    Keane, Zachary; Godfrey, Matthew; Burke, Adam; Chen, Jason; Fricke, Sebastian; Klochan, Oleh; Micolich, Adam; Beere, Harvey; Ritchie, Dave; Trunov, Kirill; Reuter, Dirk; Wieck, Andreas; Hamilton, Alex

    2011-03-01

    Nuclear magnetic resonance (NMR) is a well-known technique with widespread applications in physics, chemistry and medicine. Conventional NMR studies use inductive coils to detect the magnetic field produced by precessing nuclear spins; this approach requires on the order of 1012 spins for detection. Recently, resistive detection of NMR through the hyperfine interaction has been demonstrated with electrons in mesoscopic 2- and 1-dimensional devices based on high-quality GaAs/AlGaAs heterostructures. These studies are typically sensitive to 108 spins, enabling NMR on much smaller sample volumes. Holes are predicted to have much weaker nuclear spin coupling than electrons, which could be relevant to the emerging fields of spintronics and quantum information processing. We present a preliminary comparison between the magnitude of the NMR signal in electron and hole quantum point contacts.

  5. Scale-space point spread function based framework to boost infrared target detection algorithms

    NASA Astrophysics Data System (ADS)

    Moradi, Saed; Moallem, Payman; Sabahi, Mohamad Farzan

    2016-07-01

    Small target detection is one of the major concern in the development of infrared surveillance systems. Detection algorithms based on Gaussian target modeling have attracted most attention from researchers in this field. However, the lack of accurate target modeling limits the performance of this type of infrared small target detection algorithms. In this paper, signal to clutter ratio (SCR) improvement mechanism based on the matched filter is described in detail and effect of Point Spread Function (PSF) on the intensity and spatial distribution of the target pixels is clarified comprehensively. In the following, a new parametric model for small infrared targets is developed based on the PSF of imaging system which can be considered as a matched filter. Based on this model, a new framework to boost model-based infrared target detection algorithms is presented. In order to show the performance of this new framework, the proposed model is adopted in Laplacian scale-space algorithms which is a well-known algorithm in the small infrared target detection field. Simulation results show that the proposed framework has better detection performance in comparison with the Gaussian one and improves the overall performance of IRST system. By analyzing the performance of the proposed algorithm based on this new framework in a quantitative manner, this new framework shows at least 20% improvement in the output SCR values in comparison with Laplacian of Gaussian (LoG) algorithm.

  6. Single and Multiple Change Point Detection in Spike Trains: Comparison of Different CUSUM Methods

    PubMed Central

    Koepcke, Lena; Ashida, Go; Kretzberg, Jutta

    2016-01-01

    In a natural environment, sensory systems are faced with ever-changing stimuli that can occur, disappear or change their properties at any time. For the animal to react adequately the sensory systems must be able to detect changes in external stimuli based on its neuronal responses. Since the nervous system has no prior knowledge of the stimulus timing, changes in stimulus need to be inferred from the changes in neuronal activity, in particular increase or decrease of the spike rate, its variability, and shifted response latencies. From a mathematical point of view, this problem can be rephrased as detecting changes of statistical properties in a time series. In neuroscience, the CUSUM (cumulative sum) method has been applied to recorded neuronal responses for detecting a single stimulus change. Here, we investigate the applicability of the CUSUM approach for detecting single as well as multiple stimulus changes that induce increases or decreases in neuronal activity. Like the nervous system, our algorithm relies exclusively on previous neuronal population activities, without using knowledge about the timing or number of external stimulus changes. We apply our change point detection methods to experimental data obtained by multi-electrode recordings from turtle retinal ganglion cells, which react to changes in light stimulation with a range of typical neuronal activity patterns. We systematically examine how variations of mathematical assumptions (Poisson, Gaussian, and Gamma distributions) used for the algorithms may affect the detection of an unknown number of stimulus changes in our data and compare these CUSUM methods with the standard Rate Change method. Our results suggest which versions of the CUSUM algorithm could be useful for different types of specific data sets. PMID:27445714

  7. Single and Multiple Change Point Detection in Spike Trains: Comparison of Different CUSUM Methods.

    PubMed

    Koepcke, Lena; Ashida, Go; Kretzberg, Jutta

    2016-01-01

    In a natural environment, sensory systems are faced with ever-changing stimuli that can occur, disappear or change their properties at any time. For the animal to react adequately the sensory systems must be able to detect changes in external stimuli based on its neuronal responses. Since the nervous system has no prior knowledge of the stimulus timing, changes in stimulus need to be inferred from the changes in neuronal activity, in particular increase or decrease of the spike rate, its variability, and shifted response latencies. From a mathematical point of view, this problem can be rephrased as detecting changes of statistical properties in a time series. In neuroscience, the CUSUM (cumulative sum) method has been applied to recorded neuronal responses for detecting a single stimulus change. Here, we investigate the applicability of the CUSUM approach for detecting single as well as multiple stimulus changes that induce increases or decreases in neuronal activity. Like the nervous system, our algorithm relies exclusively on previous neuronal population activities, without using knowledge about the timing or number of external stimulus changes. We apply our change point detection methods to experimental data obtained by multi-electrode recordings from turtle retinal ganglion cells, which react to changes in light stimulation with a range of typical neuronal activity patterns. We systematically examine how variations of mathematical assumptions (Poisson, Gaussian, and Gamma distributions) used for the algorithms may affect the detection of an unknown number of stimulus changes in our data and compare these CUSUM methods with the standard Rate Change method. Our results suggest which versions of the CUSUM algorithm could be useful for different types of specific data sets.

  8. Single and Multiple Change Point Detection in Spike Trains: Comparison of Different CUSUM Methods.

    PubMed

    Koepcke, Lena; Ashida, Go; Kretzberg, Jutta

    2016-01-01

    In a natural environment, sensory systems are faced with ever-changing stimuli that can occur, disappear or change their properties at any time. For the animal to react adequately the sensory systems must be able to detect changes in external stimuli based on its neuronal responses. Since the nervous system has no prior knowledge of the stimulus timing, changes in stimulus need to be inferred from the changes in neuronal activity, in particular increase or decrease of the spike rate, its variability, and shifted response latencies. From a mathematical point of view, this problem can be rephrased as detecting changes of statistical properties in a time series. In neuroscience, the CUSUM (cumulative sum) method has been applied to recorded neuronal responses for detecting a single stimulus change. Here, we investigate the applicability of the CUSUM approach for detecting single as well as multiple stimulus changes that induce increases or decreases in neuronal activity. Like the nervous system, our algorithm relies exclusively on previous neuronal population activities, without using knowledge about the timing or number of external stimulus changes. We apply our change point detection methods to experimental data obtained by multi-electrode recordings from turtle retinal ganglion cells, which react to changes in light stimulation with a range of typical neuronal activity patterns. We systematically examine how variations of mathematical assumptions (Poisson, Gaussian, and Gamma distributions) used for the algorithms may affect the detection of an unknown number of stimulus changes in our data and compare these CUSUM methods with the standard Rate Change method. Our results suggest which versions of the CUSUM algorithm could be useful for different types of specific data sets. PMID:27445714

  9. Test sensitivity is important for detecting variability in pointing comprehension in canines.

    PubMed

    Pongrácz, Péter; Gácsi, Márta; Hegedüs, Dorottya; Péter, András; Miklósi, Adám

    2013-09-01

    Several articles have been recently published on dogs' (Canis familiaris) performance in two-way object choice experiments in which subjects had to find hidden food by utilizing human pointing. The interpretation of results has led to a vivid theoretical debate about the cognitive background of human gestural signal understanding in dogs, despite the fact that many important details of the testing method have not yet been standardized. We report three experiments that aim to reveal how some procedural differences influence adult companion dogs' performance in these tests. Utilizing a large sample in Experiment 1, we provide evidence that neither the keeping conditions (garden/house) nor the location of the testing (outdoor/indoor) affect a dogs' performance. In Experiment 2, we compare dogs' performance using three different types of pointing gestures. Dogs' performance varied between momentary distal and momentary cross-pointing but "low" and "high" performer dogs chose uniformly better than chance level if they responded to sustained pointing gestures with reinforcement (food reward and a clicking sound; "clicker pointing"). In Experiment 3, we show that single features of the aforementioned "clicker pointing" method can slightly improve dogs' success rate if they were added one by one to the momentary distal pointing method. These results provide evidence that although companion dogs show a robust performance at different testing locations regardless of their keeping conditions, the exact execution of the human gesture and additional reinforcement techniques have substantial effect on the outcomes. Consequently, researchers should standardize their methodology before engaging in debates on the comparative aspects of socio-cognitive skills because the procedures they utilize may differ in sensitivity for detecting differences.

  10. Test sensitivity is important for detecting variability in pointing comprehension in canines.

    PubMed

    Pongrácz, Péter; Gácsi, Márta; Hegedüs, Dorottya; Péter, András; Miklósi, Adám

    2013-09-01

    Several articles have been recently published on dogs' (Canis familiaris) performance in two-way object choice experiments in which subjects had to find hidden food by utilizing human pointing. The interpretation of results has led to a vivid theoretical debate about the cognitive background of human gestural signal understanding in dogs, despite the fact that many important details of the testing method have not yet been standardized. We report three experiments that aim to reveal how some procedural differences influence adult companion dogs' performance in these tests. Utilizing a large sample in Experiment 1, we provide evidence that neither the keeping conditions (garden/house) nor the location of the testing (outdoor/indoor) affect a dogs' performance. In Experiment 2, we compare dogs' performance using three different types of pointing gestures. Dogs' performance varied between momentary distal and momentary cross-pointing but "low" and "high" performer dogs chose uniformly better than chance level if they responded to sustained pointing gestures with reinforcement (food reward and a clicking sound; "clicker pointing"). In Experiment 3, we show that single features of the aforementioned "clicker pointing" method can slightly improve dogs' success rate if they were added one by one to the momentary distal pointing method. These results provide evidence that although companion dogs show a robust performance at different testing locations regardless of their keeping conditions, the exact execution of the human gesture and additional reinforcement techniques have substantial effect on the outcomes. Consequently, researchers should standardize their methodology before engaging in debates on the comparative aspects of socio-cognitive skills because the procedures they utilize may differ in sensitivity for detecting differences. PMID:23392852

  11. Experimental analysis of the auditory detection process on avian point counts

    USGS Publications Warehouse

    Simons, T.R.; Alldredge, M.W.; Pollock, K.H.; Wettroth, J.M.

    2007-01-01

    We have developed a system for simulating the conditions of avian surveys in which birds are identified by sound. The system uses a laptop computer to control a set of amplified MP3 players placed at known locations around a survey point. The system can realistically simulate a known population of songbirds under a range of factors that affect detection probabilities. The goals of our research are to describe the sources and range of variability affecting point-count estimates and to find applications of sampling theory and methodologies that produce practical improvements in the quality of bird-census data. Initial experiments in an open field showed that, on average, observers tend to undercount birds on unlimited-radius counts, though the proportion of birds counted by individual observers ranged from 81% to 132% of the actual total. In contrast to the unlimited-radius counts, when data were truncated at a 50-m radius around the point, observers overestimated the total population by 17% to 122%. Results also illustrate how detection distances decline and identification errors increase with increasing levels of ambient noise. Overall, the proportion of birds heard by observers decreased by 28 ?? 4.7% under breezy conditions, 41 ?? 5.2% with the presence of additional background birds, and 42 ?? 3.4% with the addition of 10 dB of white noise. These findings illustrate some of the inherent difficulties in interpreting avian abundance estimates based on auditory detections, and why estimates that do not account for variations in detection probability will not withstand critical scrutiny. ?? The American Ornithologists' Union, 2007.

  12. Research on acupuncture points and cortical functional activation position in cats by infrared imaging detection

    NASA Astrophysics Data System (ADS)

    Chen, Shuwang; Sha, Zhanyou; Wang, Shuhai; Wen, Huanming

    2007-12-01

    The research of the brain cognition is mainly to find out the activation position in brain according to the stimulation at present in the world. The research regards the animals as the experimental objects and explores the stimulation response on the cerebral cortex of acupuncture. It provides a new method, which can detect the activation position on the creatural cerebral cortex directly by middle-far infrared imaging. According to the theory of local temperature situation, the difference of cortical temperature maybe associate with the excitement of cortical nerve cells, the metabolism of local tissue and the local hemal circulation. Direct naked detection of temperature variety on cerebral cortex is applied by middle and far infrared imaging technology. So the activation position is ascertained. The effect of stimulation response is superior to other indirect methods. After removing the skulls on the head, full of cerebral cortex of a cat are exposed. By observing the infrared images and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing, the points are used to judge the activation position. The variety in the cortical functional sections is corresponding to the result of the acupuncture points in terms of infrared images and temperatures. According to experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture point exactly.

  13. Instrument-Free Point-of-Care Molecular Detection of Zika Virus.

    PubMed

    Song, Jinzhao; Mauk, Michael G; Hackett, Brent A; Cherry, Sara; Bau, Haim H; Liu, Changchun

    2016-07-19

    The recent outbreak of Zika virus (ZIKV) infection in the Americas and its devastating impact on fetal development have prompted the World Health Organization (WHO) to declare the ZIKV pandemic as a Public Health Emergency of International Concern. Rapid and reliable diagnostics for ZIKV are vital because ZIKV-infected individuals display no symptoms or nonspecific symptoms similar to other viral infections. Because immunoassays lack adequate sensitivity and selectivity and are unable to identify active state of infection, molecular diagnostics are an effective means to detect ZIKV soon after infection and throughout pregnancy. We report on a highly sensitive reverse-transcription loop-mediated, isothermal amplification (RT-LAMP) assay for rapid detection of ZIKV and its implementation in a simple, easy-to-use, inexpensive, point-of-care (POC) disposable cassette that carries out all the unit operations from sample introduction to detection. For thermal control of the cassette, we use a chemically heated cup without a need for electrical power. Amplification products are detected with leuco crystal violet (LCV) dye by eye without a need for instrumentation. We demonstrated the utility of our POC diagnostic system by detecting ZIKV in oral samples with sensitivity of 5 plaque-forming units (PFU) in less than 40 min. Our system is particularly suitable for resource-poor settings, where centralized laboratory facilities, funds, and trained personnel are in short supply, and for use in doctors' offices, clinics, and at home. PMID:27306491

  14. Instrument-Free Point-of-Care Molecular Detection of Zika Virus.

    PubMed

    Song, Jinzhao; Mauk, Michael G; Hackett, Brent A; Cherry, Sara; Bau, Haim H; Liu, Changchun

    2016-07-19

    The recent outbreak of Zika virus (ZIKV) infection in the Americas and its devastating impact on fetal development have prompted the World Health Organization (WHO) to declare the ZIKV pandemic as a Public Health Emergency of International Concern. Rapid and reliable diagnostics for ZIKV are vital because ZIKV-infected individuals display no symptoms or nonspecific symptoms similar to other viral infections. Because immunoassays lack adequate sensitivity and selectivity and are unable to identify active state of infection, molecular diagnostics are an effective means to detect ZIKV soon after infection and throughout pregnancy. We report on a highly sensitive reverse-transcription loop-mediated, isothermal amplification (RT-LAMP) assay for rapid detection of ZIKV and its implementation in a simple, easy-to-use, inexpensive, point-of-care (POC) disposable cassette that carries out all the unit operations from sample introduction to detection. For thermal control of the cassette, we use a chemically heated cup without a need for electrical power. Amplification products are detected with leuco crystal violet (LCV) dye by eye without a need for instrumentation. We demonstrated the utility of our POC diagnostic system by detecting ZIKV in oral samples with sensitivity of 5 plaque-forming units (PFU) in less than 40 min. Our system is particularly suitable for resource-poor settings, where centralized laboratory facilities, funds, and trained personnel are in short supply, and for use in doctors' offices, clinics, and at home.

  15. Instrument-Free Point-of-Care Molecular Detection of Zika Virus

    PubMed Central

    2016-01-01

    The recent outbreak of Zika virus (ZIKV) infection in the Americas and its devastating impact on fetal development have prompted the World Health Organization (WHO) to declare the ZIKV pandemic as a Public Health Emergency of International Concern. Rapid and reliable diagnostics for ZIKV are vital because ZIKV-infected individuals display no symptoms or nonspecific symptoms similar to other viral infections. Because immunoassays lack adequate sensitivity and selectivity and are unable to identify active state of infection, molecular diagnostics are an effective means to detect ZIKV soon after infection and throughout pregnancy. We report on a highly sensitive reverse-transcription loop-mediated, isothermal amplification (RT-LAMP) assay for rapid detection of ZIKV and its implementation in a simple, easy-to-use, inexpensive, point-of-care (POC) disposable cassette that carries out all the unit operations from sample introduction to detection. For thermal control of the cassette, we use a chemically heated cup without a need for electrical power. Amplification products are detected with leuco crystal violet (LCV) dye by eye without a need for instrumentation. We demonstrated the utility of our POC diagnostic system by detecting ZIKV in oral samples with sensitivity of 5 plaque-forming units (PFU) in less than 40 min. Our system is particularly suitable for resource-poor settings, where centralized laboratory facilities, funds, and trained personnel are in short supply, and for use in doctors’ offices, clinics, and at home. PMID:27306491

  16. Variability of Point Sources of Gamma Rays Detected by the Fermi Large-Area Telescope

    NASA Astrophysics Data System (ADS)

    Wallace, Eric

    The Large Area Telescope (LAT) aboard the Fermi Gamma-Ray Space Telescope has revolutionized gamma-ray astronomy, allowing the detection of thousands of point sources of gamma rays. Variability studies are of significant interest as a potential source of information about the emission mechanisms, and as a means to identify gamma-ray sources with known sources in other wavelengths and to improve detection sensitivity in searches for new sources. The inclusion of temporal resolution, however, adds to the already considerable complexity of the required analysis, and as a result, variability studies have generally been limited either in scope or in detail, or both, compared to time-integrated spectral analyses. pointlike is a software package designed for fast maximum likelihood analysis of LAT data, allowing for interactive and large-scale analyses. Here, we present an application of pointlike to the characterization of the variability of the full sample of known gamma-ray point sources. We describe the construction of light curves in one-month time bins, spanning the first 42 months of the Fermi mission, for a sample of 2652 sources. We discuss the use of the detection significance in individual months to improve the significance of detection of marginal sources, and show that including that measure of significance increases the set of significantly detected sources by nearly 20% compared to using only the average significance. We describe a statistical measure of the significance of variability in a light curve, and examine the variability of thesample as whole, and of subsets associated with particular source types, especially pulsars. We discuss the use of pulsars, which are generally non-variable on long timescales, to calibrate variability statistics, and to assess the importance of systematic errors in estimates of variability. Finally, we discuss the potential to extend the method to produce light curves of longer duration and finer time binning, and to search

  17. Combining isothermal rolling circle amplification and electrochemiluminescence for highly sensitive point mutation detection

    NASA Astrophysics Data System (ADS)

    Su, Qiang; Zhou, Xiaoming

    2008-12-01

    Many pathogenic and genetic diseases are associated with changes in the sequence of particular genes. We describe here a rapid and highly efficient assay for the detection of point mutation. This method is a combination of isothermal rolling circle amplification (RCA) and high sensitive electrochemluminescence (ECL) detection. In the design, a circular template generated by ligation upon the recognition of a point mutation on DNA targets was amplified isothermally by the Phi29 polymerase using a biotinylated primer. The elongation products were hybridized with tris (bipyridine) ruthenium (TBR)-tagged probes and detected in a magnetic bead based ECL platform, indicating the mutation occurrence. P53 was chosen as a model for the identification of this method. The method allowed sensitive determination of the P53 mutation from wild-type and mutant samples. The main advantage of RCA-ECL is that it can be performed under isothermal conditions and avoids the generation of false-positive results. Furthermore, ECL provides a faster, more sensitive, and economical option to currently available electrophoresis-based methods.

  18. An Instantaneous Low-Cost Point-of-Care Anemia Detection Device

    PubMed Central

    Punter-Villagrasa, Jaime; Cid, Joan; Páez-Avilés, Cristina; Rodríguez-Villarreal, Ivón; Juanola-Feliu, Esteve; Colomer-Farrarons, Jordi; Miribel-Català, Pere Ll.

    2015-01-01

    We present a small, compact and portable device for point-of-care instantaneous early detection of anemia. The method used is based on direct hematocrit measurement from whole blood samples by means of impedance analysis. This device consists of a custom electronic instrumentation and a plug-and-play disposable sensor. The designed electronics rely on straightforward standards for low power consumption, resulting in a robust and low consumption device making it completely mobile with a long battery life. Another approach could be powering the system based on other solutions like indoor solar cells, or applying energy-harvesting solutions in order to remove the batteries. The sensing system is based on a disposable low-cost label-free three gold electrode commercial sensor for 50 μL blood samples. The device capability for anemia detection has been validated through 24 blood samples, obtained from four hospitalized patients at Hospital Clínic. As a result, the response, effectiveness and robustness of the portable point-of-care device to detect anemia has been proved with an accuracy error of 2.83% and a mean coefficient of variation of 2.57% without any particular case above 5%. PMID:25690552

  19. Primer effect in the detection of mitochondrial DNA point heteroplasmy by automated sequencing.

    PubMed

    Calatayud, Marta; Ramos, Amanda; Santos, Cristina; Aluja, Maria Pilar

    2013-06-01

    The correct detection of mitochondrial DNA (mtDNA) heteroplasmy by automated sequencing presents methodological constraints. The main goals of this study are to investigate the effect of sense and distance of primers in heteroplasmy detection and to test if there are differences in the accurate determination of heteroplasmy involving transitions or transversions. A gradient of the heteroplasmy levels was generated for mtDNA positions 9477 (transition G/A) and 15,452 (transversion C/A). Amplification and subsequent sequencing with forward and reverse primers, situated at 550 and 150 bp from the heteroplasmic positions, were performed. Our data provide evidence that there is a significant difference between the use of forward and reverse primers. The forward primer is the primer that seems to give a better approximation to the real proportion of the variants. No significant differences were found concerning the distance at which the sequencing primers were placed neither between the analysis of transitions and transversions. The data collected in this study are a starting point that allows to glimpse the importance of the sequencing primers in the accurate detection of point heteroplasmy, providing additional insight into the overall automated sequencing strategy.

  20. Development of a microchip Europium nanoparticle immunoassay for sensitive point-of-care HIV detection.

    PubMed

    Liu, Jikun; Du, Bingchen; Zhang, Panhe; Haleyurgirisetty, Mohan; Zhao, Jiangqin; Ragupathy, Viswanath; Lee, Sherwin; DeVoe, Don L; Hewlett, Indira K

    2014-11-15

    Rapid, sensitive and specific diagnostic assays play an indispensable role in determination of HIV infection stages and evaluation of efficacy of antiretroviral therapy. Recently, our laboratory developed a sensitive Europium nanoparticle-based microtiter-plate immunoassay capable of detecting target analytes at subpicogram per milliliter levels without the use of catalytic enzymes and signal amplification processes. Encouraged by its sensitivity and simplicity, we continued to miniaturize this assay to a microchip platform for the purpose of converting the benchtop assay technique to a point-of-care test. It was found that detection capability of the microchip platform could be readily improved using Europium nanoparticle probes. We were able to routinely detect 5 pg/mL (4.6 attomoles) of HIV-1 p24 antigen at a signal-to-blank ratio of 1.5, a sensitivity level reasonably close to that of microtiter-plate Europium nanoparticle assay. Meanwhile, use of the microchip platform effectively reduced sample/reagent consumption 4.5 fold and shortened total assay time 2 fold in comparison with microtiter plate assays. Complex matrix substance in plasma negatively affected the microchip assays and the effects could be minimized by diluting the samples before loading. With further improvements in sensitivity, reproducibility, usability, assay process simplification, and incorporation of portable time-resolved fluorescence reader, Europium nanoparticle immunoassay technology could be adapted to meet the challenges of point-of-care diagnosis of HIV or other health-threatening pathogens at bedside or in resource-limited settings.

  1. Detecting functional connectivity change points for single-subject fMRI data.

    PubMed

    Cribben, Ivor; Wager, Tor D; Lindquist, Martin A

    2013-01-01

    Recently in functional magnetic resonance imaging (fMRI) studies there has been an increased interest in understanding the dynamic manner in which brain regions communicate with one another, as subjects perform a set of experimental tasks or as their psychological state changes. Dynamic Connectivity Regression (DCR) is a data-driven technique used for detecting temporal change points in functional connectivity between brain regions where the number and location of the change points are unknown a priori. After finding the change points, DCR estimates a graph or set of relationships between the brain regions for data that falls between pairs of change points. In previous work, the method was predominantly validated using multi-subject data. In this paper, we concentrate on single-subject data and introduce a new DCR algorithm. The new algorithm increases accuracy for individual subject data with a small number of observations and reduces the number of false positives in the estimated undirected graphs. We also introduce a new Likelihood Ratio test for comparing sparse graphs across (or within) subjects; thus allowing us to determine whether data should be combined across subjects. We perform an extensive simulation analysis on vector autoregression (VAR) data as well as to an fMRI data set from a study (n = 23) of a state anxiety induction using a socially evaluative threat challenge. The focus on single-subject data allows us to study the variation between individuals and may provide us with a deeper knowledge of the workings of the brain.

  2. ROM Plus(®): accurate point-of-care detection of ruptured fetal membranes.

    PubMed

    McQuivey, Ross W; Block, Jon E

    2016-01-01

    Accurate and timely diagnosis of rupture of fetal membranes is imperative to inform and guide gestational age-specific interventions to optimize perinatal outcomes and reduce the risk of serious complications, including preterm delivery and infections. The ROM Plus is a rapid, point-of-care, qualitative immunochromatographic diagnostic test that uses a unique monoclonal/polyclonal antibody approach to detect two different proteins found in amniotic fluid at high concentrations: alpha-fetoprotein and insulin-like growth factor binding protein-1. Clinical study results have uniformly demonstrated high diagnostic accuracy and performance characteristics with this point-of-care test that exceeds conventional clinical testing with external laboratory evaluation. The description, indications for use, procedural steps, and laboratory and clinical characterization of this assay are presented in this article. PMID:27274316

  3. Intersection Detection Based on Qualitative Spatial Reasoning on Stopping Point Clusters

    NASA Astrophysics Data System (ADS)

    Zourlidou, S.; Sester, M.

    2016-06-01

    The purpose of this research is to propose and test a method for detecting intersections by analysing collectively acquired trajectories of moving vehicles. Instead of solely relying on the geometric features of the trajectories, such as heading changes, which may indicate turning points and consequently intersections, we extract semantic features of the trajectories in form of sequences of stops and moves. Under this spatiotemporal prism, the extracted semantic information which indicates where vehicles stop can reveal important locations, such as junctions. The advantage of the proposed approach in comparison with existing turning-points oriented approaches is that it can detect intersections even when not all the crossing road segments are sampled and therefore no turning points are observed in the trajectories. The challenge with this approach is that first of all, not all vehicles stop at the same location - thus, the stop-location is blurred along the direction of the road; this, secondly, leads to the effect that nearby junctions can induce similar stop-locations. As a first step, a density-based clustering is applied on the layer of stop observations and clusters of stop events are found. Representative points of the clusters are determined (one per cluster) and in a last step the existence of an intersection is clarified based on spatial relational cluster reasoning, with which less informative geospatial clusters, in terms of whether a junction exists and where its centre lies, are transformed in more informative ones. Relational reasoning criteria, based on the relative orientation of the clusters with their adjacent ones are discussed for making sense of the relation that connects them, and finally for forming groups of stop events that belong to the same junction.

  4. Implementation of the 7-point checklist for melanoma detection on smart handheld devices.

    PubMed

    Wadhawan, Tarun; Situ, Ning; Rui, Hu; Lancaster, Keith; Yuan, Xiaojing; Zouridakis, George

    2011-01-01

    In this paper we implement the 7-point checklist, a set of dermoscopic criteria widely used by clinicians for melanoma detection, on smart handheld devices, such as the Apple iPhone and iPad. The application developed is using sophisticated image processing and pattern recognition algorithms, yet it is light enough to run on a handheld device with limited memory and computational speed. When combined with a commercially available handheld dermoscope that provides proper lesion illumination, this application provides a truly self-contained handheld system for melanoma detection. Such a device can be used in a clinical setting for routine skin screening, or as an assistive diagnostic device in underserved areas and in developing countries with limited healthcare infrastructure. PMID:22255015

  5. Detection mechanisms employing single event upsets in dynamic random access memories used as radiation sensors

    NASA Astrophysics Data System (ADS)

    Darambara, D. G.; Spyrou, N. M.

    1994-12-01

    A hardware system is being designed and constructed for the detection of neutrons, with a view to using it in neutron imaging and elemental analysis. A feasibility study was initially carried out to demonstrate that dynamic Random Access Memories (dRAMs) can be used as heavy charged particle detectors and furthermore be made sensitive to neutrons. We are interested, however, in constructing a detector that will be position sensitive, and hence carried out experiments to investigate the relative sensitivity of specific elements within the dRAM chips. The findings from these initial system tests highlight the usefulness of such a device as a position sensitive radiation detector. This paper aims to explain and give a review of most aspects concerning the soft error (SE) performance using dRAM as a radiation sensor.

  6. The focal account: Indirect lie detection need not access unconscious, implicit knowledge.

    PubMed

    Street, Chris N H; Richardson, Daniel C

    2015-12-01

    People are poor lie detectors, but accuracy can be improved by making the judgment indirectly. In a typical demonstration, participants are not told that the experiment is about deception at all. Instead, they judge whether the speaker appears, say, tense or not. Surprisingly, these indirect judgments better reflect the speaker's veracity. A common explanation is that participants have an implicit awareness of deceptive behavior, even when they cannot explicitly identify it. We propose an alternative explanation. Attending to a range of behaviors, as explicit raters do, can lead to conflict: A speaker may be thinking hard (indicating deception) but not tense (indicating honesty). In 2 experiments, we show that the judgment (and in turn the correct classification rate) is the result of attending to a single behavior, as indirect raters are instructed to do. Indirect lie detection does not access implicit knowledge, but simply focuses the perceiver on more useful cues.

  7. The focal account: Indirect lie detection need not access unconscious, implicit knowledge.

    PubMed

    Street, Chris N H; Richardson, Daniel C

    2015-12-01

    People are poor lie detectors, but accuracy can be improved by making the judgment indirectly. In a typical demonstration, participants are not told that the experiment is about deception at all. Instead, they judge whether the speaker appears, say, tense or not. Surprisingly, these indirect judgments better reflect the speaker's veracity. A common explanation is that participants have an implicit awareness of deceptive behavior, even when they cannot explicitly identify it. We propose an alternative explanation. Attending to a range of behaviors, as explicit raters do, can lead to conflict: A speaker may be thinking hard (indicating deception) but not tense (indicating honesty). In 2 experiments, we show that the judgment (and in turn the correct classification rate) is the result of attending to a single behavior, as indirect raters are instructed to do. Indirect lie detection does not access implicit knowledge, but simply focuses the perceiver on more useful cues. PMID:26301728

  8. Advanced Yellow Fever Virus Genome Detection in Point-of-Care Facilities and Reference Laboratories

    PubMed Central

    Patel, Pranav; Yillah, Jasmin; Weidmann, Manfred; Méndez, Jairo A.; Nakouné, Emmanuel Rivalyn; Niedrig, Matthias

    2012-01-01

    Reported methods for the detection of the yellow fever viral genome are beset by limitations in sensitivity, specificity, strain detection spectra, and suitability to laboratories with simple infrastructure in areas of endemicity. We describe the development of two different approaches affording sensitive and specific detection of the yellow fever genome: a real-time reverse transcription-quantitative PCR (RT-qPCR) and an isothermal protocol employing the same primer-probe set but based on helicase-dependent amplification technology (RT-tHDA). Both assays were evaluated using yellow fever cell culture supernatants as well as spiked and clinical samples. We demonstrate reliable detection by both assays of different strains of yellow fever virus with improved sensitivity and specificity. The RT-qPCR assay is a powerful tool for reference or diagnostic laboratories with real-time PCR capability, while the isothermal RT-tHDA assay represents a useful alternative to earlier amplification techniques for the molecular diagnosis of yellow fever by field or point-of-care laboratories. PMID:23052311

  9. An integrated lateral flow assay for effective DNA amplification and detection at the point of care.

    PubMed

    Choi, Jane Ru; Hu, Jie; Gong, Yan; Feng, Shangsheng; Wan Abas, Wan Abu Bakar; Pingguan-Murphy, Belinda; Xu, Feng

    2016-05-10

    Lateral flow assays (LFAs) have been extensively explored in nucleic acid testing (NAT) for medical diagnostics, food safety analysis and environmental monitoring. However, the amount of target nucleic acid in a raw sample is usually too low to be directly detected by LFAs, necessitating the process of amplification. Even though cost-effective paper-based amplification techniques have been introduced, they have always been separately performed from LFAs, hence increasing the risk of reagent loss and cross-contaminations. To date, integrating paper-based nucleic acid amplification into colorimetric LFA in a simple, portable and cost-effective manner has not been introduced. Herein, we developed an integrated LFA with the aid of a specially designed handheld battery-powered system for effective amplification and detection of targets in resource-poor settings. Interestingly, using the integrated paper-based loop-mediated isothermal amplification (LAMP)-LFA, we successfully performed highly sensitive and specific target detection, achieving a detection limit of as low as 3 × 10(3) copies of target DNA, which is comparable to the conventional tube-based LAMP-LFA in an unintegrated format. The device may serve in conjunction with a simple paper-based sample preparation to create a fully integrated paper-based sample-to-answer diagnostic device for point-of-care testing (POCT) in the near future. PMID:27010033

  10. Towards detection and diagnosis of Ebola virus disease at point-of-care.

    PubMed

    Kaushik, Ajeet; Tiwari, Sneham; Dev Jayant, Rahul; Marty, Aileen; Nair, Madhavan

    2016-01-15

    Ebola outbreak-2014 (mainly Zaire strain related Ebola virus) has been declared most widely spread deadly persistent epidemic due to unavailability of rapid diagnostic, detection, and therapeutics. Ebola virus disease (EVD), a severe viral hemorrhagic fever syndrome caused by Ebola virus (EBOV) is transmitted by direct contact with the body fluids of infected person and objects contaminated with virus or infected animals. World Health Organization (WHO) has declared EVD epidemic as public health emergency of international concern with severe global economic burden. At fatal EBOV infection stage, patients usually die before the antibody response. Currently, rapid blood tests to diagnose EBOV infection include the antigen or antibodies capture using ELISA and RNA detection using RT/Q-PCR within 3-10 days after the onset of symptoms. Moreover, few nanotechnology-based colorimetric and paper-based immunoassay methods have been recently reported to detect Ebola virus. Unfortunately, these methods are limited to laboratory only. As state-of-the art (SoA) diagnostics time to confirm Ebola infection, varies from 6h to about 3 days, it causes delay in therapeutic approaches. Thus developing a cost-effective, rapid, sensitive, and selective sensor to detect EVD at point-of-care (POC) is certainly worth exploring to establish rapid diagnostics to decide therapeutics. This review highlights SoA of Ebola diagnostics and also a call to develop rapid, selective and sensitive POC detection of EBOV for global health care. We propose that adopting miniaturized electrochemical EBOV immunosensing can detect virus level at pM concentration within ∼40min compared to 3 days of ELISA test at nM levels.

  11. Developing rapid, point-of-care, multiplex detection for use in lateral flow devices

    NASA Astrophysics Data System (ADS)

    Rao, R. S.; Albala, J. S.; Lane, S. L.; Matthews, D. L.; Fisher, A. M.; Lambert, J. L.; Coleman, M. A.

    2005-11-01

    Immunoassays have been widely used in commercial, scientific and medical research for detection and quantification of analytes in complex mixtures. There is however a need for a point-of-care, multiplex diagnostic assays capable of providing rapid and quantitative measurements of analytes present in samples that are sufficiently simple to carry out without use of a laboratory or individuals trained in chemical analysis. We are developing a fluorescent lateral flow immunoassay platform to perform simultaneous, multiplexed detection of analytes in a complex fluid mixture along with instrumentation to optically quantitate the analytes in the sample. Our prototype imaging system is based on conventional 16-bit CCD optics, which enables the development of a rugged diagnostic instrument that can be further scaled down for point-of-care applications. We have compared protein microarrays with lateral flow assays (LFAs) to determine the sensitivity of each system for the measurement of distinct proteins in complex samples. We are pursuing the LFA platform such that it can easily be scaled to meet the requirements of any given screening application, and be implemented for use in a medical or surgical setting.

  12. Automatic Single Tree Detection in Plantations using UAV-based Photogrammetric Point clouds

    NASA Astrophysics Data System (ADS)

    Kattenborn, T.; Sperlich, M.; Bataua, K.; Koch, B.

    2014-08-01

    For reasons of documentation, management and certification there is a high interest in efficient inventories of palm plantations on the single plant level. Recent developments in unmanned aerial vehicle (UAV) technology facilitate spatial and temporal flexible acquisition of high resolution 3D data. Common single tree detection approaches are based on Very High Resolution (VHR) satellite or Airborne Laser Scanning (ALS) data. However, VHR data is often limited to clouds and does commonly not allow for height measurements. VHR and in particualar ALS data are characterized by high relatively high acquisition costs. Sperlich et al. (2013) already demonstrated the high potential of UAV-based photogrammetric point clouds for single tree detection using pouring algorithms. This approach was adjusted and improved for an application on palm plantation. The 9.4ha test site on Tarawa, Kiribati, comprised densely scattered growing palms, as well as abundant undergrowth and trees. Using a standard consumer grade camera mounted on an octocopter two flight campaigns at 70m and 100m altitude were performed to evaluate the effect Ground Sampling Distance (GSD) and image overlap. To avoid comission errors and improve the terrain interpolation the point clouds were classified based on the geometric characteristics of the classes, i.e. (1) palm, (2) other vegetation (3) and ground. The mapping accuracy amounts for 86.1 % for the entire study area and 98.2 % for dense growing palm stands. We conclude that this flexible and automatic approach has high capabilities for operational use.

  13. Trend estimation and change point detection in individual climatic series using flexible regression methods

    NASA Astrophysics Data System (ADS)

    Bates, Bryson C.; Chandler, Richard E.; Bowman, Adrian W.

    2012-08-01

    Over recent years, considerable attention has been given to the problem of detecting trends and change points (discontinuities) in climatic series. This has led to the use of a plethora of detection techniques, ranging from the very simple (e.g., linear regression and t-tests) to the relatively complex (e.g., Markov chain Monte Carlo methods). However, many of these techniques are quite restricted in their range of application and care is needed to avoid misinterpretation of their results. In this paper we highlight the availability of modern regression methods that allow for both smooth trends and abrupt changes, and a discontinuity test that enables discrimination between the two. Our framework can accommodate constant mean levels, linear or smooth trends, and can test for genuine change points in an objective and data-driven way. We demonstrate its capabilities using the winter (December-March) North Atlantic Oscillation, an annual mean relative humidity series and a seasonal (June to October) typhoon count series as case studies. We show that the framework is less restrictive than many alternatives in allowing the data to speak for themselves and can give different and more credible results from those of conventional methods. The research findings from such analyses can be used to appropriately inform the design of subsequent studies of temporal changes in underlying physical mechanisms, and the development of policy responses that are appropriate for smoothly varying rather than abrupt climate change (and vice versa).

  14. Detectability limitations with 3-D point reconstruction algorithms using digital radiography

    SciTech Connect

    Lindgren, Erik

    2015-03-31

    The estimated impact of pores in clusters on component fatigue will be highly conservative when based on 2-D rather than 3-D pore positions. To 3-D position and size defects using digital radiography and 3-D point reconstruction algorithms in general require a lower inspection time and in some cases work better with planar geometries than X-ray computed tomography. However, the increase in prior assumptions about the object and the defects will increase the intrinsic uncertainty in the resulting nondestructive evaluation output. In this paper this uncertainty arising when detecting pore defect clusters with point reconstruction algorithms is quantified using simulations. The simulation model is compared to and mapped to experimental data. The main issue with the uncertainty is the possible masking (detectability zero) of smaller defects around some other slightly larger defect. In addition, the uncertainty is explored in connection to the expected effects on the component fatigue life and for different amount of prior object-defect assumptions made.

  15. Computer program for analysis of impedance cardiography signals enabling manual correction of points detected automatically

    NASA Astrophysics Data System (ADS)

    Oleksiak, Justyna; Cybulski, Gerard

    2014-11-01

    The aim of this work was to create a computer program, written in LabVIEW, which enables the visualization and analysis of hemodynamic parameters. It allows the user to import data collected using ReoMonitor, an ambulatory monitoring impedance cardiography (AICG) device. The data include one channel of the ECG and one channel of the first derivative of the impedance signal (dz/dt) sampled at 200Hz and the base impedance signal (Z0) sampled every 8s. The program consist of two parts: a bioscope allowing the presentation of traces (ECG, AICG, Z0) and an analytical portion enabling the detection of characteristic points on the signals and automatic calculation of hemodynamic parameters. The detection of characteristic points in both signals is done automatically, with the option to make manual corrections, which may be necessary to avoid "false positive" recognitions. This application is used to determine the values of basic hemodynamic variables: pre-ejection period (PEP), left ventricular ejection time (LVET), stroke volume (SV), cardiac output (CO), and heart rate (HR). It leaves room for further development of additional features, for both the analysis panel and the data acquisition function.

  16. Assessing Point-of-Care Device Specifications and Needs for Pathogen Detection in Emergencies and Disasters

    PubMed Central

    Kost, Gerald J.; Mecozzi, Daniel M.; Brock, T. Keith; Curtis, Corbin M.

    2012-01-01

    Background We assessed point-of-care device specifications and needs for pathogen detection in urgent care, emergencies, and disasters. Methods We surveyed American Association for Clinical Chemistry members and compared responses to those of disaster experts. Online SurveyMonkey questions covered performance characteristics, device design, pathogen targets, and other specifications. Results For disasters, respondents preferred direct sample collection with a disposable test cassette that stores biohazardous material (P<0.001). They identified methicillin-resistant Staphylococcus aureus, Salmonella typhi, Vibrio cholerae, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae as high priority pathogens. First responders were deemed the professional group who should perform POC testing in disasters (P<0.001). Conclusions Needs assessment now is requisite for competitive funding, so the results in this report will be useful to investigators preparing grant applications. Point-of-care devices used in disasters should address the needs of first responders, who give high priority to contamination-free whole-blood sampling, superior performance pathogen detection, and HIV-1/2 blood donor screening. There was surprising concordance of preferences among different professional groups, which presages formulation of global consensus guidelines to assist high impact preparedness. PMID:23049471

  17. Assessing Point-of-Care Device Specifications and Needs for Pathogen Detection in Emergencies and Disasters.

    PubMed

    Kost, Gerald J; Mecozzi, Daniel M; Brock, T Keith; Curtis, Corbin M

    2012-06-01

    BACKGROUND: We assessed point-of-care device specifications and needs for pathogen detection in urgent care, emergencies, and disasters. METHODS: We surveyed American Association for Clinical Chemistry members and compared responses to those of disaster experts. Online SurveyMonkey questions covered performance characteristics, device design, pathogen targets, and other specifications. RESULTS: For disasters, respondents preferred direct sample collection with a disposable test cassette that stores biohazardous material (P<0.001). They identified methicillin-resistant Staphylococcus aureus, Salmonella typhi, Vibrio cholerae, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae as high priority pathogens. First responders were deemed the professional group who should perform POC testing in disasters (P<0.001). CONCLUSIONS: Needs assessment now is requisite for competitive funding, so the results in this report will be useful to investigators preparing grant applications. Point-of-care devices used in disasters should address the needs of first responders, who give high priority to contamination-free whole-blood sampling, superior performance pathogen detection, and HIV-1/2 blood donor screening. There was surprising concordance of preferences among different professional groups, which presages formulation of global consensus guidelines to assist high impact preparedness.

  18. Point Cloud Based Change Detection - an Automated Approach for Cloud-based Services

    NASA Astrophysics Data System (ADS)

    Collins, Patrick; Bahr, Thomas

    2016-04-01

    The fusion of stereo photogrammetric point clouds with LiDAR data or terrain information derived from SAR interferometry has a significant potential for 3D topographic change detection. In the present case study latest point cloud generation and analysis capabilities are used to examine a landslide that occurred in the village of Malin in Maharashtra, India, on 30 July 2014, and affected an area of ca. 44.000 m2. It focuses on Pléiades high resolution satellite imagery and the Airbus DS WorldDEMTM as a product of the TanDEM-X mission. This case study was performed using the COTS software package ENVI 5.3. Integration of custom processes and automation is supported by IDL (Interactive Data Language). Thus, ENVI analytics is running via the object-oriented and IDL-based ENVITask API. The pre-event topography is represented by the WorldDEMTM product, delivered with a raster of 12 m x 12 m and based on the EGM2008 geoid (called pre-DEM). For the post-event situation a Pléiades 1B stereo image pair of the AOI affected was obtained. The ENVITask "GeneratePointCloudsByDenseImageMatching" was implemented to extract passive point clouds in LAS format from the panchromatic stereo datasets: • A dense image-matching algorithm is used to identify corresponding points in the two images. • A block adjustment is applied to refine the 3D coordinates that describe the scene geometry. • Additionally, the WorldDEMTM was input to constrain the range of heights in the matching area, and subsequently the length of the epipolar line. The "PointCloudFeatureExtraction" task was executed to generate the post-event digital surface model from the photogrammetric point clouds (called post-DEM). Post-processing consisted of the following steps: • Adding the geoid component (EGM 2008) to the post-DEM. • Pre-DEM reprojection to the UTM Zone 43N (WGS-84) coordinate system and resizing. • Subtraction of the pre-DEM from the post-DEM. • Filtering and threshold based classification of

  19. Model-wise and point-wise random sample consensus for robust regression and outlier detection.

    PubMed

    El-Melegy, Moumen T

    2014-11-01

    Popular regression techniques often suffer at the presence of data outliers. Most previous efforts to solve this problem have focused on using an estimation algorithm that minimizes a robust M-estimator based error criterion instead of the usual non-robust mean squared error. However the robustness gained from M-estimators is still low. This paper addresses robust regression and outlier detection in a random sample consensus (RANSAC) framework. It studies the classical RANSAC framework and highlights its model-wise nature for processing the data. Furthermore, it introduces for the first time a point-wise strategy of RANSAC. New estimation algorithms are developed following both the model-wise and point-wise RANSAC concepts. The proposed algorithms' theoretical robustness and breakdown points are investigated in a novel probabilistic setting. While the proposed concepts and algorithms are generic and general enough to adopt many regression machineries, the paper focuses on multilayered feed-forward neural networks in solving regression problems. The algorithms are evaluated on synthetic and real data, contaminated with high degrees of outliers, and compared to existing neural network training algorithms. Furthermore, to improve the time performance, parallel implementations of the two algorithms are developed and assessed to utilize the multiple CPU cores available on nowadays computers. PMID:25047916

  20. Detection of Geometric Keypoints and its Application to Point Cloud Coarse Registration

    NASA Astrophysics Data System (ADS)

    Bueno, M.; Martínez-Sánchez, J.; González-Jorge, H.; Lorenzo, H.

    2016-06-01

    Acquisition of large scale scenes, frequently, involves the storage of large amount of data, and also, the placement of several scan positions to obtain a complete object. This leads to a situation with a different coordinate system in each scan position. Thus, a preprocessing of it to obtain a common reference frame is usually needed before analysing it. Automatic point cloud registration without locating artificial markers is a challenging field of study. The registration of millions or billions of points is a demanding task. Subsampling the original data usually solves the situation, at the cost of reducing the precision of the final registration. In this work, a study of the subsampling via the detection of keypoints and its capability to apply in coarse alignment is performed. The keypoints obtained are based on geometric features of each individual point, and are extracted using the Difference of Gaussians approach over 3D data. The descriptors include features as eigenentropy, change of curvature and planarity. Experiments demonstrate that the coarse alignment, obtained through these keypoints outperforms the coarse registration root mean squared error of an operator by 3 - 5 cm. The applicability of these keypoints is tested and verified in five different case studies.

  1. Automated Detection of Geomorphic Features in LiDAR Point Clouds of Various Spatial Density

    NASA Astrophysics Data System (ADS)

    Dorninger, Peter; Székely, Balázs; Zámolyi, András.; Nothegger, Clemens

    2010-05-01

    considerably varying considerably because of the various base points that were needed to cover the whole landslide. The resulting point spacing is approximately 20 cm. The achievable accuracy was about 10 cm. The airborne data was acquired with mean point densities of 2 points per square-meter. The accuracy of this dataset was about 15 cm. The second testing site is an area of the Leithagebirge in Burgenland, Austria. The data was acquired by an airborne Riegl LMS-Q560 laser scanner mounted on a helicopter. The mean point density was 6-8 points per square with an accuracy better than 10 cm. We applied our processing chain on the datasets individually. First, they were transformed to local reference frames and fine adjustments of the individual scans respectively flight strips were applied. Subsequently, the local regression planes were determined for each point of the point clouds and planar features were extracted by means of the proposed approach. It turned out that even small displacements can be detected if the number of points used for the fit is enough to define a parallel but somewhat displaced plane. Smaller cracks and erosional incisions do not disturb the plane fitting, because mostly they are filtered out as outliers. A comparison of the different campaigns of the Doren site showed exciting matches of the detected geomorphic structures. Although the geomorphic structure of the Leithagebirge differs from the Doren landslide, and the scales of the two studies were also different, reliable results were achieved in both cases. Additionally, the approach turned out to be highly robust against points which were not located on the terrain. Hence, no false positives were determined within the dense vegetation above the terrain, while it was possible to cover the investigated areas completely with reliable planes. In some cases, however, some structures in the tree crowns were also recognized, but these small patches could be very well sorted out from the geomorphically

  2. Automatic 3D Building Detection and Modeling from Airborne LiDAR Point Clouds

    NASA Astrophysics Data System (ADS)

    Sun, Shaohui

    Urban reconstruction, with an emphasis on man-made structure modeling, is an active research area with broad impact on several potential applications. Urban reconstruction combines photogrammetry, remote sensing, computer vision, and computer graphics. Even though there is a huge volume of work that has been done, many problems still remain unsolved. Automation is one of the key focus areas in this research. In this work, a fast, completely automated method to create 3D watertight building models from airborne LiDAR (Light Detection and Ranging) point clouds is presented. The developed method analyzes the scene content and produces multi-layer rooftops, with complex rigorous boundaries and vertical walls, that connect rooftops to the ground. The graph cuts algorithm is used to separate vegetative elements from the rest of the scene content, which is based on the local analysis about the properties of the local implicit surface patch. The ground terrain and building rooftop footprints are then extracted, utilizing the developed strategy, a two-step hierarchical Euclidean clustering. The method presented here adopts a "divide-and-conquer" scheme. Once the building footprints are segmented from the terrain and vegetative areas, the whole scene is divided into individual pendent processing units which represent potential points on the rooftop. For each individual building region, significant features on the rooftop are further detected using a specifically designed region-growing algorithm with surface smoothness constraints. The principal orientation of each building rooftop feature is calculated using a minimum bounding box fitting technique, and is used to guide the refinement of shapes and boundaries of the rooftop parts. Boundaries for all of these features are refined for the purpose of producing strict description. Once the description of the rooftops is achieved, polygonal mesh models are generated by creating surface patches with outlines defined by detected

  3. Making a semi-convex Focus area in a Focus+Glue+Context map, considering map visibility and transport access points

    NASA Astrophysics Data System (ADS)

    Hirako, Y.; Yamamoto, D.; Takahashi, N.

    2016-04-01

    We previously implemented the Focus+Glue+Context map system EMMA that provides local detailed data in Focus, global context data in Context, and connection data between both in the same view. Introducing the Glue area between Focus and Context makes it possible to provide uniform scaling for the two latter areas. This paper enhances EMMA through the implementation of a Focus creation function that considers transportation access points, such as stations and bus stops. The enhanced EMMA searches a route from the current location to the transportation access point, and allows users to identify the spatial relationship between the various locations in a small-scale Context, and view the route from the current location to the transportation access points in a large-scale Focus. However, if Focus is too large because of unnecessary areas used to identify the route, some parts of Context might be hidden by Focus. The proposed system solves this problem by implementing the following functions: (1) it searches stations that are adjacent to the current location and makes a semiconvex Focus that includes the current location and those stations in order for Focus to include really necessary areas. (2) It reduces Focus distortion by setting a fixed point as the center of the Focus area. (3) It smoothens the Focus shape in order to improve visibility in the Glue area. We developed a prototype of the proposed system that implements these functions.

  4. Delay analysis of an integrated voice and data access protocol with collision detection for multimedia satellite networks

    NASA Astrophysics Data System (ADS)

    Poon, Charles C. K.; Suda, Tatsuya

    1992-03-01

    The novel multiple-access scheme for multimedia satellite networks presented is based on a combination of FDMA and TDMA, integrating both circuit and packet-switching techniques. While the circuit-switching method is used to transmit such stream-type traffic as real-time voice communications, packet-switching is used to transmit such 'bursty' traffic as interactive data. A ground radio network is assumed for control signaling; the tone sense multiple access/partial collision detection scheme is implemented on this network to enhance the integrated access scheme's performance.

  5. [Detection of the point of communication by pneumoperitoneum at the surgery for pleuroperitoneal communication].

    PubMed

    Okubo, T; Takahashi, H; Kaneko, Y; Kurokawa, T; Yokoyama, K; Motohara, T

    2010-05-01

    A 53-year-old male was admitted to our hospital because of dyspnea. Chest radiograph showed a massive right-sided hydrothorax. He was suffering from chronic renal failure and had undergone continuous ambulatory peritoneal dialysis (CAPD) for 8 months. The diagnosis of pleuroperitoneal communication (PPC) was made using injection of indigocarmine into the peritoneal cavity with subsequent pleural detection by thoracocentesis. Injection of contrast media into the peritoneal cavity showed a dome shaped radio-opaque shadow which is located on the diaphragmatic dome followed by the movement of contrast media into the thoracic cavity. Video-assisted thoracic surgery (VATS) was performed under general anesthesia. To identify the point of communication, the method of detecting air leakage was employed. A bleb like lesion on which the hole existed was observed at the center of the diaphragm, and air leakage was identified by filling the thoracic cavity with saline. The pressure in the peritoneal cavity was maintained at 10 mmHg by continuous CO2 inflation. Direct closure was performed to repair the PPC, which succesfully stopped the air leakage. CAPD could be restarted immediately after surgery. No recurrence of hydrothorax has been detected for more than 14 months after surgery. PMID:20446603

  6. Single Nanoparticle Detection Using Far-field Emission of Photonic Molecule around the Exceptional Point

    PubMed Central

    Zhang, Nan; Liu, Shuai; Wang, Kaiyang; Gu, Zhiyuan; Li, Meng; Yi, Ningbo; Xiao, Shumin; Song, Qinghai

    2015-01-01

    Highly sensitive, label-free detection methods have important applications in fundamental research and healthcare diagnostics. To date, the detection of single nanoparticles has remained largely dependent on extremely precise spectral measurement, which relies on high-cost equipment. Here, we demonstrate a simple but very nontrivial mechanism for the label-free sizing of nanoparticles using the far-field emission of a photonic molecule (PM) around an exceptional point (EP). By attaching a nanoparticle to a PM around an EP, the main resonant behaviors are strongly disturbed. In addition to typical mode splitting, we find that the far-field pattern of the PM is significantly changed. Taking a heteronuclear diatomic PM as an example, we demonstrate that a single nanoparticle, whose radius is as small as 1 nm to 7 nm, can be simply monitored through the variation of the far-field pattern. Compared with conventional methods, our approach is much easier and does not rely on high-cost equipment. In addition, this research will illuminate new advances in single nanoparticle detection. PMID:26149067

  7. Distance-based microfluidic quantitative detection methods for point-of-care testing.

    PubMed

    Tian, Tian; Li, Jiuxing; Song, Yanling; Zhou, Leiji; Zhu, Zhi; Yang, Chaoyong James

    2016-04-01

    Equipment-free devices with quantitative readout are of great significance to point-of-care testing (POCT), which provides real-time readout to users and is especially important in low-resource settings. Among various equipment-free approaches, distance-based visual quantitative detection methods rely on reading the visual signal length for corresponding target concentrations, thus eliminating the need for sophisticated instruments. The distance-based methods are low-cost, user-friendly and can be integrated into portable analytical devices. Moreover, such methods enable quantitative detection of various targets by the naked eye. In this review, we first introduce the concept and history of distance-based visual quantitative detection methods. Then, we summarize the main methods for translation of molecular signals to distance-based readout and discuss different microfluidic platforms (glass, PDMS, paper and thread) in terms of applications in biomedical diagnostics, food safety monitoring, and environmental analysis. Finally, the potential and future perspectives are discussed. PMID:26928571

  8. Distance-based microfluidic quantitative detection methods for point-of-care testing.

    PubMed

    Tian, Tian; Li, Jiuxing; Song, Yanling; Zhou, Leiji; Zhu, Zhi; Yang, Chaoyong James

    2016-04-01

    Equipment-free devices with quantitative readout are of great significance to point-of-care testing (POCT), which provides real-time readout to users and is especially important in low-resource settings. Among various equipment-free approaches, distance-based visual quantitative detection methods rely on reading the visual signal length for corresponding target concentrations, thus eliminating the need for sophisticated instruments. The distance-based methods are low-cost, user-friendly and can be integrated into portable analytical devices. Moreover, such methods enable quantitative detection of various targets by the naked eye. In this review, we first introduce the concept and history of distance-based visual quantitative detection methods. Then, we summarize the main methods for translation of molecular signals to distance-based readout and discuss different microfluidic platforms (glass, PDMS, paper and thread) in terms of applications in biomedical diagnostics, food safety monitoring, and environmental analysis. Finally, the potential and future perspectives are discussed.

  9. Detection of spatial change points in the mean and covariances of multivariate simultaneous autoregressive models.

    PubMed

    Otto, Philipp; Schmid, Wolfgang

    2016-09-01

    In this paper, we propose a test procedure to detect change points of multidimensional autoregressive processes. The considered process differs from typical applied spatial autoregressive processes in that it is assumed to evolve from a predefined center into every dimension. Additionally, structural breaks in the process can occur at a certain distance from the predefined center. The main aim of this paper is to detect such spatial changes. In particular, we focus on shifts in the mean and the autoregressive parameter. The proposed test procedure is based on the likelihood-ratio approach. Eventually, the goodness-of-fit values of the estimators are compared for different shifts. Moreover, the empirical distribution of the test statistic of the likelihood-ratio test is obtained via Monte Carlo simulations. We show that the generalized Gumbel distribution seems to be a suitable limiting distribution of the proposed test statistic. Finally, we discuss the detection of lung cancer in computed tomography scans and illustrate the proposed test procedure.

  10. a Robust Registration Algorithm for Point Clouds from Uav Images for Change Detection

    NASA Astrophysics Data System (ADS)

    Al-Rawabdeh, A.; Al-Gurrani, H.; Al-Durgham, K.; Detchev, I.; He, F.; El-Sheimy, N.; Habib, A.

    2016-06-01

    Landslides are among the major threats to urban landscape and manmade infrastructure. They often cause economic losses, property damages, and loss of lives. Temporal monitoring data of landslides from different epochs empowers the evaluation of landslide progression. Alignment of overlapping surfaces from two or more epochs is crucial for the proper analysis of landslide dynamics. The traditional methods for point-cloud-based landslide monitoring rely on using a variation of the Iterative Closest Point (ICP) registration procedure to align any reconstructed surfaces from different epochs to a common reference frame. However, sometimes the ICP-based registration can fail or may not provide sufficient accuracy. For example, point clouds from different epochs might fit to local minima due to lack of geometrical variability within the data. Also, manual interaction is required to exclude any non-stable areas from the registration process. In this paper, a robust image-based registration method is introduced for the simultaneous evaluation of all registration parameters. This includes the Interior Orientation Parameters (IOPs) of the camera and the Exterior Orientation Parameters (EOPs) of the involved images from all available observation epochs via a bundle block adjustment with self-calibration. Next, a semi-global dense matching technique is implemented to generate dense 3D point clouds for each epoch using the images captured in a particular epoch separately. The normal distances between any two consecutive point clouds can then be readily computed, because the point clouds are already effectively co-registered. A low-cost DJI Phantom II Unmanned Aerial Vehicle (UAV) was customised and used in this research for temporal data collection over an active soil creep area in Lethbridge, Alberta, Canada. The customisation included adding a GPS logger and a Large-Field-Of-View (LFOV) action camera which facilitated capturing high-resolution geo-tagged images in two epochs

  11. Point-of-care platelet function tests: detection of platelet inhibition induced by nonopioid analgesic drugs.

    PubMed

    Scharbert, Gisela; Gebhardt, Kristina; Sow, Zacharia; Duris, Monika; Deusch, Engelbert; Kozek-Langenecker, Sibylle

    2007-12-01

    Detection of platelet inhibition is of clinical relevance in the preinterventional risk-benefit assessment in chronic low-back-pain patients scheduled for invasive pain therapy. We evaluated the sensitivity of various point-of-care platelet function tests for the detection of platelet inhibition induced by nonopioid analgesic drugs. After Institutional Review Board approval and informed consent, citrated whole blood from 40 patients with chronic unspecific low back pain was investigated before and 30 min after intravenous infusion of the study medication consisting of diclofenac 75 mg (plus orphenadrin 30 mg; Neodolpasse; Fresenius Kabi Austria GmbH, Austria), parecoxib 40 mg (Dynastat; Pharmacia Europe EEIG, UK), paracetamol 1 g (Perfalgan; Bieffe Medital S.P.A., Italy), or normal saline in a randomized, cross-over, double-blinded, placebo-controlled study. Platelet function was assessed using the PFA-100 platelet function analyzer and thromboelastometry, as well as impedance aggregometry (in the last 17 patients recruited after it became commercially available). Sensitivity for detecting diclofenac-induced platelet inhibition was 85% for the PFA-100 using epinephrine as agonist and 94% for arachidonic acid-induced impedance aggregometry. ADP-induced platelet function tests, as well as cytochalasin D-modified thromboelastometry were unreliable. All tests had a low incidence of false-positive test results after normal saline. Paracetamol and parecoxib had no significant platelet inhibiting effect. The PFA-100 using epinephrine as agonist and arachidonic acid-induced impedance aggregometry are recommended for the detection of cyclooxygenase-I-inhibiting effects of nonsteroidal anti-inflammatory drugs such as diclofenac. Our findings confirm that a single rescue dose of paracetamol and parecoxib has no antiplatelet effect. PMID:17982319

  12. Use of dew-point detection for quantitative measurement of sweating rate

    NASA Technical Reports Server (NTRS)

    Brengelmann, G. L.; Mckeag, M.; Rowell, L. B.

    1975-01-01

    A method of measuring sweat rate (SR) based on detection of dew point (DP) is proposed which has advantages that may be attractive to other laboratories concerned with recording SR from selected areas of skin. It is similar to other methods in that dry gas is passed through a capsule which isolates several square centimeters of skin surface. The difference is in the means of determining how much gaseous water is carried off in the effluent moist gas. The DP detector used is free of the drawbacks of previous devices. DP is obtained through the fundamental technique of determining the temperature at which condensate forms on a mirror. Variations in DP are tracked rapidly, and accurately (+ or - 0.8 C nominal, sensitivity + or - 0.05 C) over a wide range ( -40 C to +50 C) without measurable hysteresis. The detector asembly is rugged and readily opened for cleaning and inspection.

  13. Tunable graphene quantum point contact transistor for DNA detection and characterization

    PubMed Central

    Girdhar, Anuj; Sathe, Chaitanya; Schulten, Klaus; Leburton, Jean-Pierre

    2015-01-01

    A graphene membrane conductor containing a nanopore in a quantum point contact (QPC) geometry is a promising candidate to sense, and potentially sequence, DNA molecules translocating through the nanopore. Within this geometry, the shape, size, and position of the nanopore as well as the edge configuration influences the membrane conductance caused by the electrostatic interaction between the DNA nucleotides and the nanopore edge. It is shown that the graphene conductance variations resulting from DNA translocation can be enhanced by choosing a particular geometry as well as by modulating the graphene Fermi energy, which demonstrates the ability to detect conformational transformations of a double-stranded DNA, as well as the passage of individual base pairs of a single-stranded DNA molecule through the nanopore. PMID:25765702

  14. Detection of pointing errors with CMOS-based camera in intersatellite optical communications

    NASA Astrophysics Data System (ADS)

    Yu, Si-yuan; Ma, Jing; Tan, Li-ying

    2005-01-01

    For very high data rates, intersatellite optical communications hold a potential performance edge over microwave communications. Acquisition and Tracking problem is critical because of the narrow transmit beam. A single array detector in some systems performs both spatial acquisition and tracking functions to detect pointing errors, so both wide field of view and high update rate is required. The past systems tend to employ CCD-based camera with complex readout arrangements, but the additional complexity reduces the applicability of the array based tracking concept. With the development of CMOS array, CMOS-based cameras can employ the single array detector concept. The area of interest feature of the CMOS-based camera allows a PAT system to specify portion of the array. The maximum allowed frame rate increases as the size of the area of interest decreases under certain conditions. A commercially available CMOS camera with 105 fps @ 640×480 is employed in our PAT simulation system, in which only part pixels are used in fact. Beams angle varying in the field of view can be detected after getting across a Cassegrain telescope and an optical focus system. Spot pixel values (8 bits per pixel) reading out from CMOS are transmitted to a DSP subsystem via IEEE 1394 bus, and pointing errors can be computed by the centroid equation. It was shown in test that: (1) 500 fps @ 100×100 is available in acquisition when the field of view is 1mrad; (2)3k fps @ 10×10 is available in tracking when the field of view is 0.1mrad.

  15. Indoor Navigation from Point Clouds: 3d Modelling and Obstacle Detection

    NASA Astrophysics Data System (ADS)

    Díaz-Vilariño, L.; Boguslawski, P.; Khoshelham, K.; Lorenzo, H.; Mahdjoubi, L.

    2016-06-01

    In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

  16. The Analysis of Optical, Direct Detection Communication Systems with Point Process Observations

    NASA Astrophysics Data System (ADS)

    Brady, David Paul

    1990-01-01

    The central theme of this work is the analysis of direct-detection optical communication channels based on point process observations. For example, we consider an optical DPSK receiver which is based on a binary hypothesis test with conditionally Poisson count observations. The error probability is influenced by the transmitting laser phase noise as well as the statistical nature of light, and decreases to the quantum limit as the transmitting laser linewidth vanishes. We bound the bit error rate by bounding the conditional photon arrival rates, and were shown to converge as the laser linewidth decreases. We also derive the exact error rate of a noncoherent, optical, asynchronous, CDMA system. The receiver utilizes fiber optic tap delay lines to create and correlate the signature sequence with the received point process, and compares an electron count to a threshold to decide for the data of the user of interest. The optical intensity on a surface illuminated by several phase-coherent signals is determined, and it is shown that the approximation of noncoherent addition in the fiber optic tap delay line is justified. The bit error rate is found for arbitrary photomultipliers and signature sequence sets, adheres fully to the semi-classical model of light, and does not depend on approximations for large user groups, strong received optical fields, or chip synchronism. The capacity of a direct-detection photon counting channel is addressed in this work. The limiting form of the capacity is found as the signal and noise energies increase proportionally, and it is shown that the capacity grows logarithmically with the signal energy constraint. When the noise energy increases polynomially with the signal energy, the limiting capacity coincides with that of a Gaussian channel with a positivity and variance constraint. Bounds on the capacity are considered for small and moderate energies by restricting attention to binary inputs. These bounds are arbitrarily tight, and are

  17. A Multiplexed Diagnostic Platform for Point-of-Care Pathogen Detection

    SciTech Connect

    Regan, J F; Letant, S E; Adams, K L; Mahnke, R C; Nguyen, N T; Dzenitis, J M; Hindson, B J; Hadley, D R; Makarewicz, T J; Henderer, B D; Breneman, J W; Tammero, L F; Ortiz, J I; Derlet, R W; Cohen, S; Colston, W W; McBride, M T; Birch, J M

    2008-02-04

    We developed an automated point-of-care diagnostic instrument that is capable of analyzing nasal swab samples for the presence of respiratory diseases. This robust instrument, called FluIDx, performs autonomous multiplexed RT-PCR reactions that are analyzed by microsphere xMAP technology. We evaluated the performance of FluIDx, in comparison rapid tests specific for influenza and respiratory syncytial virus, in a clinical study performed at the UC Davis Medical Center. The clinical study included samples positive for RSV (n = 71), influenza A (n = 16), influenza B (n = 4), adenovirus (n = 5), parainfluenza virus (n = 2), and 44 negative samples, according to a composite reference method. FluIDx and the rapid tests detected 85.9% and 62.0% of the RSV positive samples, respectively. Similar sensitivities were recorded for the influenza B samples; whereas the influenza A samples were poorly detected, likely due to the utilization of an influenza A signature that did not accurately match currently circulating influenza A strains. Data for all pathogens were compiled and indicate that FluIDx is more sensitive than the rapid tests, detecting 74.2% (95% C.I. of 64.7-81.9%) of the positive samples in comparison to 53.6% (95% C.I. of 43.7-63.2%) for the rapid tests. The higher sensitivity of FluIDx was partially offset by a lower specificity, 77.3% versus 100.0%. Overall, these data suggest automated flow-through PCR-based instruments that perform multiplexed assays can successfully screen clinical samples for infectious diseases.

  18. Detection of change points in underlying earthquake rates, with application to global mega-earthquakes

    NASA Astrophysics Data System (ADS)

    Touati, Sarah; Naylor, Mark; Main, Ian

    2016-02-01

    The recent spate of mega-earthquakes since 2004 has led to speculation of an underlying change in the global `background' rate of large events. At a regional scale, detecting changes in background rate is also an important practical problem for operational forecasting and risk calculation, for example due to volcanic processes, seismicity induced by fluid injection or withdrawal, or due to redistribution of Coulomb stress after natural large events. Here we examine the general problem of detecting changes in background rate in earthquake catalogues with and without correlated events, for the first time using the Bayes factor as a discriminant for models of varying complexity. First we use synthetic Poisson (purely random) and Epidemic-Type Aftershock Sequence (ETAS) models (which also allow for earthquake triggering) to test the effectiveness of many standard methods of addressing this question. These fall into two classes: those that evaluate the relative likelihood of different models, for example using Information Criteria or the Bayes Factor; and those that evaluate the probability of the observations (including extreme events or clusters of events) under a single null hypothesis, for example by applying the Kolmogorov-Smirnov and `runs' tests, and a variety of Z-score tests. The results demonstrate that the effectiveness among these tests varies widely. Information Criteria worked at least as well as the more computationally expensive Bayes factor method, and the Kolmogorov-Smirnov and runs tests proved to be the relatively ineffective in reliably detecting a change point. We then apply the methods tested to events at different thresholds above magnitude M ≥ 7 in the global earthquake catalogue since 1918, after first declustering the catalogue. This is most effectively done by removing likely correlated events using a much lower magnitude threshold (M ≥ 5), where triggering is much more obvious. We find no strong evidence that the background rate of large

  19. Simultaneous detection of four garlic viruses by multiplex reverse transcription PCR and their distribution in Indian garlic accessions.

    PubMed

    Majumder, S; Baranwal, V K

    2014-06-01

    Indian garlic is infected with Onion yellow dwarf virus (OYDV), Shallot latent virus (SLV), Garlic common latent virus (GarCLV) and allexiviruses. Identity and distribution of garlic viruses in various garlic accessions from different geographical regions of India were investigated. OYDV and allexiviruses were observed in all the garlic accessions, while SLV and GarCLV were observed only in a few accessions. A multiplex reverse transcription (RT)-PCR method was developed for the simultaneous detection and identification of OYDV, SLV, GarCLV and Allexivirus infecting garlic accessions in India. This multiplex protocol standardized in this study will be useful in indexing of garlic viruses and production of virus free seed material. PMID:24598229

  20. Simultaneous detection of four garlic viruses by multiplex reverse transcription PCR and their distribution in Indian garlic accessions.

    PubMed

    Majumder, S; Baranwal, V K

    2014-06-01

    Indian garlic is infected with Onion yellow dwarf virus (OYDV), Shallot latent virus (SLV), Garlic common latent virus (GarCLV) and allexiviruses. Identity and distribution of garlic viruses in various garlic accessions from different geographical regions of India were investigated. OYDV and allexiviruses were observed in all the garlic accessions, while SLV and GarCLV were observed only in a few accessions. A multiplex reverse transcription (RT)-PCR method was developed for the simultaneous detection and identification of OYDV, SLV, GarCLV and Allexivirus infecting garlic accessions in India. This multiplex protocol standardized in this study will be useful in indexing of garlic viruses and production of virus free seed material.

  1. The VA Point-of-Care Precision Oncology Program: Balancing Access with Rapid Learning in Molecular Cancer Medicine.

    PubMed

    Fiore, Louis D; Brophy, Mary T; Turek, Sara; Kudesia, Valmeek; Ramnath, Nithya; Shannon, Colleen; Ferguson, Ryan; Pyarajan, Saiju; Fiore, Melissa A; Hornberger, John; Lavori, Philip

    2016-01-01

    The Department of Veterans Affairs (VA) recognized the need to balance patient-centered care with responsible creation of generalizable knowledge on the effectiveness of molecular medicine tools. Embracing the principles of the rapid learning health-care system, a new clinical program called the Precision Oncology Program (POP) was created in New England. The POP integrates generalized knowledge about molecular medicine in cancer with a database of observations from previously treated veterans. The program assures access to modern genomic oncology practice in the veterans affairs (VA), removes disparities of access across the VA network of clinical centers, disseminates the products of learning that are generalizable to non-VA settings, and systematically presents opportunities for patients to participate in clinical trials of targeted therapeutics. PMID:26949343

  2. The VA Point-of-Care Precision Oncology Program: Balancing Access with Rapid Learning in Molecular Cancer Medicine

    PubMed Central

    Fiore, Louis D.; Brophy, Mary T.; Turek, Sara; Kudesia, Valmeek; Ramnath, Nithya; Shannon, Colleen; Ferguson, Ryan; Pyarajan, Saiju; Fiore, Melissa A.; Hornberger, John; Lavori, Philip

    2016-01-01

    The Department of Veterans Affairs (VA) recognized the need to balance patient-centered care with responsible creation of generalizable knowledge on the effectiveness of molecular medicine tools. Embracing the principles of the rapid learning health-care system, a new clinical program called the Precision Oncology Program (POP) was created in New England. The POP integrates generalized knowledge about molecular medicine in cancer with a database of observations from previously treated veterans. The program assures access to modern genomic oncology practice in the veterans affairs (VA), removes disparities of access across the VA network of clinical centers, disseminates the products of learning that are generalizable to non-VA settings, and systematically presents opportunities for patients to participate in clinical trials of targeted therapeutics. PMID:26949343

  3. Integrated photonic decoder with complementary code processing and balanced detection for two-dimensional optical code division multiple access.

    PubMed

    Takiguchi, K; Okuno, M; Takahashi, H; Moriwaki, O

    2007-04-01

    We propose a novel integrated photonic decoder for two-dimensional (time spreading, wavelength hopping) optical code division multiple access. The decoder is composed of multiplexers-demultiplexers, variable delay lines, and a coupler, which processes complementary codes and utilizes balanced detection to reduce unwanted cross-correlation interference. We successfully carried out a 10 Gbit/s transmission that demonstrated its effectiveness.

  4. Points of interest and visual dictionaries for automatic retinal lesion detection.

    PubMed

    Rocha, A; Carvalho, T; Jelinek, H F; Goldenstein, S; Wainer, J

    2012-08-01

    In this paper, we present an algorithm to detect the presence of diabetic retinopathy (DR)-related lesions from fundus images based on a common analytical approach that is capable of identifying both red and bright lesions without requiring specific pre- or postprocessing. Our solution constructs a visual word dictionary representing points of interest (PoIs) located within regions marked by specialists that contain lesions associated with DR and classifies the fundus images based on the presence or absence of these PoIs as normal or DR-related pathology. The novelty of our approach is in locating DR lesions in the optic fundus images using visual words that combines feature information contained within the images in a framework easily extendible to different types of retinal lesions or pathologies and builds a specific projection space for each class of interest (e.g., white lesions such as exudates or normal regions) instead of a common dictionary for all classes. The visual words dictionary was applied to classifying bright and red lesions with classical cross validation and cross dataset validation to indicate the robustness of this approach. We obtained an area under the curve (AUC) of 95.3% for white lesion detection and an AUC of 93.3% for red lesion detection using fivefold cross validation and our own data consisting of 687 images of normal retinae, 245 images with bright lesions, 191 with red lesions, and 109 with signs of both bright and red lesions. For cross dataset analysis, the visual dictionary also achieves compelling results using our images as the training set and the RetiDB and Messidor images as test sets. In this case, the image classification resulted in an AUC of 88.1% when classifying the RetiDB dataset and in an AUC of 89.3% when classifying the Messidor dataset, both cases for bright lesion detection. The results indicate the potential for training with different acquisition images under different setup conditions with a high accuracy of

  5. Detection of fallen trees in ALS point clouds using a Normalized Cut approach trained by simulation

    NASA Astrophysics Data System (ADS)

    Polewski, Przemyslaw; Yao, Wei; Heurich, Marco; Krzystek, Peter; Stilla, Uwe

    2015-07-01

    Downed dead wood is regarded as an important part of forest ecosystems from an ecological perspective, which drives the need for investigating its spatial distribution. Based on several studies, Airborne Laser Scanning (ALS) has proven to be a valuable remote sensing technique for obtaining such information. This paper describes a unified approach to the detection of fallen trees from ALS point clouds based on merging short segments into whole stems using the Normalized Cut algorithm. We introduce a new method of defining the segment similarity function for the clustering procedure, where the attribute weights are learned from labeled data. Based on a relationship between Normalized Cut's similarity function and a class of regression models, we show how to learn the similarity function by training a classifier. Furthermore, we propose using an appearance-based stopping criterion for the graph cut algorithm as an alternative to the standard Normalized Cut threshold approach. We set up a virtual fallen tree generation scheme to simulate complex forest scenarios with multiple overlapping fallen stems. This simulated data is then used as a basis to learn both the similarity function and the stopping criterion for Normalized Cut. We evaluate our approach on 5 plots from the strictly protected mixed mountain forest within the Bavarian Forest National Park using reference data obtained via a manual field inventory. The experimental results show that our method is able to detect up to 90% of fallen stems in plots having 30-40% overstory cover with a correctness exceeding 80%, even in quite complex forest scenes. Moreover, the performance for feature weights trained on simulated data is competitive with the case when the weights are calculated using a grid search on the test data, which indicates that the learned similarity function and stopping criterion can generalize well on new plots.

  6. Knowledge guided object detection and identification in 3D point clouds

    NASA Astrophysics Data System (ADS)

    Karmacharya, A.; Boochs, F.; Tietz, B.

    2015-05-01

    Modern instruments like laser scanner and 3D cameras or image based techniques like structure from motion produce huge point clouds as base for further object analysis. This has considerably changed the way of data compilation away from selective manually guided processes towards automatic and computer supported strategies. However it's still a long way to achieve the quality and robustness of manual processes as data sets are mostly very complex. Looking at existing strategies 3D data processing for object detections and reconstruction rely heavily on either data driven or model driven approaches. These approaches come with their limitation on depending highly on the nature of data and inability to handle any deviation. Furthermore, the lack of capabilities to integrate other data or information in between the processing steps further exposes their limitations. This restricts the approaches to be executed with strict predefined strategy and does not allow deviations when and if new unexpected situations arise. We propose a solution that induces intelligence in the processing activities through the usage of semantics. The solution binds the objects along with other related knowledge domains to the numerical processing to facilitate the detection of geometries and then uses experts' inference rules to annotate them. The solution was tested within the prototypical application of the research project "Wissensbasierte Detektion von Objekten in Punktwolken für Anwendungen im Ingenieurbereich (WiDOP)". The flexibility of the solution is demonstrated through two entirely different USE Case scenarios: Deutsche Bahn (German Railway System) for the outdoor scenarios and Fraport (Frankfort Airport) for the indoor scenarios. Apart from the difference in their environments, they provide different conditions, which the solution needs to consider. While locations of the objects in Fraport were previously known, that of DB were not known at the beginning.

  7. Increasing equity of access to point-of-use water treatment products through social marketing and entrepreneurship: a case study in western Kenya.

    PubMed

    Freeman, Matthew C; Quick, Robert E; Abbott, Daniel P; Ogutu, Paul; Rheingans, Richard

    2009-09-01

    Point-of-use water chlorination reduces diarrhoea risk by 25-85%. Social marketing has expanded access to inexpensive sodium hypochlorite for water treatment, at a cost of less than US$0.01 per day, in Kenya. To increase product access, women's groups in western Kenya were trained to educate neighbours and sell health products to generate income. We evaluated this programme's impact on equity of access to water treatment products in a cross-sectional survey. We surveyed 487 randomly selected households in eight communities served by the women's groups. Overall, 20% (range 5-39%) of households in eight communities purchased and used chlorine, as confirmed by residual chlorine observed in stored water. Multivariate models using illiteracy and the poorest socioeconomic status as a referent showed that persons with at least some primary education (OR 2.5, 95% CI 1.8, 3.5) or secondary education (OR 5.4, 95% CI 1.6, 17.5) and persons in the four wealthiest quintiles (OR 2.5, 95% CI 1.0, 6.0) were more likely to chlorinate stored water. While this implementation model was associated with good product penetration and use, barriers to access to inexpensive water treatment remained among the very poor and less educated. PMID:19491503

  8. Increasing equity of access to point-of-use water treatment products through social marketing and entrepreneurship: a case study in western Kenya.

    PubMed

    Freeman, Matthew C; Quick, Robert E; Abbott, Daniel P; Ogutu, Paul; Rheingans, Richard

    2009-09-01

    Point-of-use water chlorination reduces diarrhoea risk by 25-85%. Social marketing has expanded access to inexpensive sodium hypochlorite for water treatment, at a cost of less than US$0.01 per day, in Kenya. To increase product access, women's groups in western Kenya were trained to educate neighbours and sell health products to generate income. We evaluated this programme's impact on equity of access to water treatment products in a cross-sectional survey. We surveyed 487 randomly selected households in eight communities served by the women's groups. Overall, 20% (range 5-39%) of households in eight communities purchased and used chlorine, as confirmed by residual chlorine observed in stored water. Multivariate models using illiteracy and the poorest socioeconomic status as a referent showed that persons with at least some primary education (OR 2.5, 95% CI 1.8, 3.5) or secondary education (OR 5.4, 95% CI 1.6, 17.5) and persons in the four wealthiest quintiles (OR 2.5, 95% CI 1.0, 6.0) were more likely to chlorinate stored water. While this implementation model was associated with good product penetration and use, barriers to access to inexpensive water treatment remained among the very poor and less educated.

  9. Heterodyne detection using spectral line pairing for spectral phase encoding optical code division multiple access and dynamic dispersion compensation.

    PubMed

    Yang, Yi; Foster, Mark; Khurgin, Jacob B; Cooper, A Brinton

    2012-07-30

    A novel coherent optical code-division multiple access (OCDMA) scheme is proposed that uses spectral line pairing to generate signals suitable for heterodyne decoding. Both signal and local reference are transmitted via a single optical fiber and a simple balanced receiver performs sourceless heterodyne detection, canceling speckle noise and multiple-access interference (MAI). To validate the idea, a 16 user fully loaded phase encoded system is simulated. Effects of fiber dispersion on system performance are studied as well. Both second and third order dispersion management is achieved by using a spectral phase encoder to adjust phase shifts of spectral components at the optical network unit (ONU).

  10. Activity pattern detection in electroneurographic and electromyogram signals through a heteroscedastic change-point method.

    PubMed

    Esquivel-Frausto, M E; Guerrero, J A; Macías-Díaz, J E

    2010-04-01

    In this work, we propose a heteroscedastic method in the detection of activity patterns of electroneurographic and electromyogram signals involved in rhythmic activities of nerves and muscles, respectively. The electric behavior observed in such signals is characterized by phases of activity and silence. The beginning and the length of electrically active and electrically silent phases in a signal allow us to quantitatively analyze the changes and the effects on a rhythmic activity produced by experimental changes. In order to distinguish between these two phases, signals are assumed to be a sample of a time-dependent, normally distributed random variable with non-constant variance, and that the determination of the variance at each point allows us to determine in which phase is the signal. The parameters of the model are determined by means of an iterative process which maximizes the log-likelihood under the proposed model. Moreover, we apply our method to the determination of the activity phases and silence phases in sequences of experimental and synthetic electroneurographic and electromyogram signals. The results obtained with synthetic data show that the method performs well in the determination of these activity patterns. Finally, the study of particular signals simulated under a generalized autoregressive conditional heteroscedasticity model suggests the robustness of the method with respect to the assumption of independence.

  11. Bioaerosol standoff detection and correlation assessment with concentration and viability point sensors

    NASA Astrophysics Data System (ADS)

    Buteau, Sylvie; Simard, Jean-Robert; Rowsell, Susan; Roy, Gilles

    2010-10-01

    A standoff bioaerosol sensor based on intensified range-gated spectrometric detection of Laser Induced Fluorescence was used to spectrally characterize bioaerosol simulants during in-chamber and open-air releases at Suffield, Canada, in August 2008 from a standoff position. In total, 42 in-chamber Bacillus atrophaeus (formerly Bacillus subtilis var globigii; BG) cloud and 27 open-air releases of either BG, Pantoea agglomerans (formerly Erwinia herbicola; EH), MS2 and ovalbumin (OV) were generated. The clouds were refereed by different point sensors including Aerodynamic Particle Sizer (APS) and slit or impingers samplers. The APS monitored the particle size distribution and concentration and the samplers characterized the viable portion of the cloud. The extracted spectral signatures show robustness to different degree. The correlation assessment showed good results in most cases where the LIF signal to noise ratio was significant. The sensor 4σ sensitivity was evaluated to 1 300, 600, 100 and 30 ppl for BG, OV, MS2 and EH respectively. Correlation results are presented by plotting the SINBAHD metric versus the corresponding particle concentration, in which case, the obtained slope is proportional to the material fluorescence cross-section. The different acquired signal is hence compared in terms of their fluorescence cross-section additionally to their spectral characteristics.

  12. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    NASA Astrophysics Data System (ADS)

    2005-03-01

    Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”. This radio image of the central region of the Milky Way Galaxy holds a new radio source, GCRT J1745-3009. The arrow points to an expanding ring of debris expelled by a supernova. CREDIT: N.E. Kassim et al., Naval Research Laboratory, NRAO/AUI/NSF Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “"We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 — five bursts in fact, and repeating at remarkably constant intervals.” Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation’s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source. “Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce

  13. Novel wavelength division multiplex-radio over fiber-passive optical network architecture for multiple access points based on multitone generation and triple sextupling frequency

    NASA Astrophysics Data System (ADS)

    Cheng, Guangming; Guo, Banghong; Liu, Songhao; Huang, Xuguang

    2014-01-01

    An innovative wavelength division multiplex-radio over fiber-passive optical network architecture for multiple access points (AP) based on multitone generation and triple sextupling frequency is proposed and demonstrated. A dual-drive Mach-Zehnder modulator (DD-MZM) is utilized to realize the multitone generation. Even sidebands are suppressed to make the adjacent frequency separation twice the frequency of the local oscillator by adjusting the modulation voltage of the DD-MZM. Due to adopting three fiber Bragg gratings to reflect the unmodulated sidebands for uplink communications source free at optical network unit (ONU), is achieved. The system can support at least three APs at one ONU simultaneously with a 30 km single-mode fiber (SMF) transmission and 5 Gb/s data rate both for uplink and downlink communications. The theoretical analysis and simulation results show the architecture has an excellent performance and will be a promising candidate in future hybrid access networks.

  14. A hierarchical model combining distance sampling and time removal to estimate detection probability during avian point counts

    USGS Publications Warehouse

    Amundson, Courtney L.; Royle, J. Andrew; Handel, Colleen M.

    2014-01-01

    Imperfect detection during animal surveys biases estimates of abundance and can lead to improper conclusions regarding distribution and population trends. Farnsworth et al. (2005) developed a combined distance-sampling and time-removal model for point-transect surveys that addresses both availability (the probability that an animal is available for detection; e.g., that a bird sings) and perceptibility (the probability that an observer detects an animal, given that it is available for detection). We developed a hierarchical extension of the combined model that provides an integrated analysis framework for a collection of survey points at which both distance from the observer and time of initial detection are recorded. Implemented in a Bayesian framework, this extension facilitates evaluating covariates on abundance and detection probability, incorporating excess zero counts (i.e. zero-inflation), accounting for spatial autocorrelation, and estimating population density. Species-specific characteristics, such as behavioral displays and territorial dispersion, may lead to different patterns of availability and perceptibility, which may, in turn, influence the performance of such hierarchical models. Therefore, we first test our proposed model using simulated data under different scenarios of availability and perceptibility. We then illustrate its performance with empirical point-transect data for a songbird that consistently produces loud, frequent, primarily auditory signals, the Golden-crowned Sparrow (Zonotrichia atricapilla); and for 2 ptarmigan species (Lagopus spp.) that produce more intermittent, subtle, and primarily visual cues. Data were collected by multiple observers along point transects across a broad landscape in southwest Alaska, so we evaluated point-level covariates on perceptibility (observer and habitat), availability (date within season and time of day), and abundance (habitat, elevation, and slope), and included a nested point

  15. Research on infrared dim-point target detection and tracking under sea-sky-line complex background

    NASA Astrophysics Data System (ADS)

    Dong, Yu-xing; Li, Yan; Zhang, Hai-bo

    2011-08-01

    Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system, the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties .There are some traditional point target detection algorithms, such as adaptive background prediction detecting method. When background has dispersion-decreasing structure, the traditional target detection algorithms would be more useful. But when the background has large gray gradient, such as sea-sky-line, sea waves etc .The bigger false-alarm rate will be taken in these local area .It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature ,in our opinion , from the perspective of mathematics, the detection of dim-point targets in image is about singular function analysis .And from the perspective image processing analysis , the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection, its essence is a separation of target and background of different singularity characteristics .The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore, the purpose of the image preprocessing is to reduce the effects from noise, also to raise the SNR of image, and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics , the median filter is used to

  16. Asynchronous detection of optical code division multiple access signals using a bandwidth-efficient and wavelength-aware receiver.

    PubMed

    Fok, Mable P; Deng, Yanhua; Prucnal, Paul R

    2010-04-01

    We experimentally demonstrate what we believe to be a novel detection scheme for interfacing asynchronous optical code division multiple access (CDMA) signals with an electronic clock and data recovery system that operates only at the baseband bandwidth. This allows using a large optical bandwidth expansion factor in which the optical chip rate is much larger than the bandwidth of the optoelectronic receiver. The received optical CDMA signal is launched into a four-wave-mixing-based wavelength-aware all-optical front end that rejects multiaccess interference, followed by an amplitude-noise suppression stage comprised of a semiconductor optical amplifier. The clean signal is then converted into a non-return-to-zero-like signal by a baseband receiver. Using the proposed detection scheme, asynchronous transmission and detection of optical CDMA signals is implemented. With the novel detection scheme, the classic CDMA near-far problem is mitigated, and error-free detection is easily obtained.

  17. Target accessibility and signal specificity in live-cell detection of BMP-4 mRNA using molecular beacons.

    PubMed

    Rhee, Won Jong; Santangelo, Philip J; Jo, Hanjoong; Bao, Gang

    2008-03-01

    The ability to visualize mRNA in single living cells and monitor in real-time the changes of mRNA level and localization can provide unprecedented opportunities for biological and disease studies. However, the mRNA detection specificity and sensitivity are critically dependent on the selection of target sequences and their accessibility. We carried out an extensive study of the target accessibility of BMP-4 mRNA using 10 different designs of molecular beacons (MBs), and identified the optimal beacon design. Specifically, for MB design 1 and 8 (MB1 and MB8), the fluorescent intensities from BMP-4 mRNA correlated well with the GFP signal after upregulating BMP-4 and co-expressing GFP using adenovirus, and the knockdown of BMP-4 mRNA using siRNA significantly reduced the beacon signals, demonstrating detection specificity. The beacon specificity was further confirmed using blocking RNA and in situ hybridization. We found that fluorescence signal from MBs depends critically on target sequences; the target sequences corresponding to siRNA sites may not be good sites for beacon-based mRNA detection, and vice versa. Possible beacon design rules are identified and approaches for enhancing target accessibility are discussed. This has significant implications to MB design for live cell mRNA detection.

  18. Evaluating the accessibility and utility of HIV-related point-of-care diagnostics for maternal health in rural South Africa: a study protocol

    PubMed Central

    Mashamba-Thompson, T P; Drain, P K; Sartorius, B

    2016-01-01

    Introduction Poor healthcare access is a major barrier to receiving antenatal care and a cause of high maternal mortality in South Africa (SA). ‘Point-of-care’ (POC) diagnostics is a powerful emerging healthcare approach to improve healthcare access. This study focuses on evaluating the accessibility and utility of POC diagnostics for maternal health in rural SA primary healthcare (PHC) clinics in order to generate a model framework of implementation of POC diagnostics in rural South African clinics. Method and analyses We will use several research methods, including a systematic review, quasi-experiments, survey, key informant interviews and audits. We will conduct a systematic review and experimental study to determine the impact of POC diagnostics on maternal health. We will perform a cross-sectional case study of 100 randomly selected rural primary healthcare clinics in KwaZulu-Natal to measure the context and patterns of POC diagnostics access and usage by maternal health providers and patients. We will conduct interviews with relevant key stakeholders to determine the reasons for POC deficiencies regarding accessibility and utility of HIV-related POC diagnostics for maternal health. We will also conduct a vertical audit to investigate all the quality aspects of POC diagnostic services including diagnostic accuracy in a select number of clinics. On the basis of information gathered, we will propose a model framework for improved implementation of POC diagnostics in rural South African public healthcare clinics. Statistical (Stata-13) and thematic (NVIVO) data analysis will be used in this study. Ethics and dissemination The study protocol was approved by the Ethics Committee of the University of KwaZulu-Natal (BE 484/14) and the KwaZulu-Natal Department of Health based on the Helsinki Declaration (HRKM 40/15). Findings of this study will be disseminated electronically and in print. They will be presented to conferences related to HIV/AIDS, diagnostics

  19. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    NASA Astrophysics Data System (ADS)

    2005-03-01

    Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”. This radio image of the central region of the Milky Way Galaxy holds a new radio source, GCRT J1745-3009. The arrow points to an expanding ring of debris expelled by a supernova. CREDIT: N.E. Kassim et al., Naval Research Laboratory, NRAO/AUI/NSF Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “"We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 — five bursts in fact, and repeating at remarkably constant intervals.” Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation’s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source. “Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce

  20. 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

  1. Signal detection theory, the exclusion failure paradigm and weak consciousness--evidence for the access/phenomenal distinction?

    PubMed

    Irvine, Elizabeth

    2009-06-01

    Block [Block, N. (2005). Two neural correlates of consciousness. Trends in Cognitive Science, 9, 46-52] and Snodgrass (2006) claim that a signal detection theory (SDT) analysis of qualitative difference paradigms, in particular the exclusion failure paradigm, reveals cases of phenomenal consciousness without access consciousness. This claim is unwarranted on several grounds. First, partial cognitive access rather than a total lack of cognitive access can account for exclusion failure results. Second, Snodgrass's Objective Threshold/Strategic (OT/S) model of perception relies on a problematic 'enable' approach to perception that denies the possibility of intentional control of unconscious perception and any effect of following different task instructions on the presence/absence of phenomenal consciousness. Many of Block's purported examples of phenomenal consciousness without cognitive access also rely on this problematic approach. Third, qualitative difference paradigms may index only a subset of access consciousness. Thus, qualitative difference paradigms like exclusion failure cannot be used to isolate phenomenal consciousness, any attempt to do so still faces serious methodological problems.

  2. VAP, a Versatile Access Point for the Endoplasmic Reticulum: Review and analysis of FFAT-like motifs in the VAPome.

    PubMed

    Murphy, Sarah E; Levine, Tim P

    2016-08-01

    Dysfunction of VAMP-associated protein (VAP) is associated with neurodegeneration, both Amyotrophic Lateral Sclerosis and Parkinson's disease. Here we summarize what is known about the intracellular interactions of VAP in humans and model organisms. VAP is a simple, small and highly conserved protein on the cytoplasmic face of the endoplasmic reticulum (ER). It is the sole protein on that large organelle that acts as a receptor for cytoplasmic proteins. This may explain the extremely wide range of interacting partners of VAP, with components of many cellular pathways binding it to access the ER. Many proteins that bind VAP also target other intracellular membranes, so VAP is a component of multiple molecular bridges at membrane contact sites between the ER and other organelles. So far approximately 100 proteins have been identified in the VAP interactome (VAPome), of which a small minority have a "two phenylalanines in an acidic tract" (FFAT) motif as it was originally defined. We have analyzed the entire VAPome in humans and yeast using a simple algorithm that identifies many more FFAT-like motifs. We show that approximately 50% of the VAPome binds directly or indirectly via the VAP-FFAT interaction. We also review evidence on pathogenesis in genetic disorders of VAP, which appear to arise from reduced overall VAP levels, leading to ER stress. It is not possible to identify one single interaction that underlies disease. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.

  3. Access to Mammography Facilities and Detection of Breast Cancer by Screening Mammography: A GIS Approach.

    PubMed

    Rahman, Selina; Price, James H; Dignan, Mark; Rahman, Saleh; Lindquist, Peter S; Jordan, Timothy R

    2009-01-01

    OBJECTIVES: The objective of the study was to examine the association between access to mammography facilities and utilization of screening mammography in an urban population. METHODS: Data on female breast cancer cases were obtained from an extensive mammography surveillance project. Distance to mammography facilities was measured by using GIS, which was followed by measuring geographical access to mammography facilities using Floating Catchment Area (FCA) method (considering all available facilities within an arbitrary radius from the woman's residence by using Arc GIS 9.0 software). RESULTS: Of 2,024 women, 91.4% were Caucasian; age ranged from 25 to 98 years; most (95%) were non-Hispanic in origin. Logistic regression found age, family history, hormone replacement therapy, physician recommendation, and breast cancer stage at diagnosis to be significant predictors of having had a previous mammogram. Women having higher access to mammography facilities were less likely to have had a previous mammogram compared to women who had low access, considering all the facilities within 10 miles (OR=0.41, CI=0.22-0.76), 30 miles (OR=0.52, CI=0.29-0.91) and 40 miles (OR=0.51, CI=0.28-0.92) radiuses. CONCLUSIONS: Physical distance to mammography facilities does not necessarily predict utilization of mammogram and greater access does not assure greater utilizations, due to constraints imposed by socio economic and cultural barriers. Future studies should focus on measuring access to mammography facilities capturing a broader dimension of access considering qualitative aspect of facilities, as well as other travel impedances. PMID:20628557

  4. Integrated optical detection of autonomous capillary microfluidic immunoassays:a hand-held point-of-care prototype.

    PubMed

    Novo, P; Chu, V; Conde, J P

    2014-07-15

    The miniaturization of biosensors using microfluidics has potential in enabling the development of point-of-care devices, with the added advantages of reduced time and cost of analysis with limits-of-detection comparable to those obtained through traditional laboratory techniques. Interfacing microfluidic devices with the external world can be difficult especially in aspects involving fluid handling and the need for simple sample insertion that avoids special equipment or trained personnel. In this work we present a point-of-care prototype system by integrating capillary microfluidics with a microfabricated photodiode array and electronic instrumentation into a hand-held unit. The capillary microfluidic device is capable of autonomous and sequential fluid flow, including control of the average fluid velocity at any given point of the analysis. To demonstrate the functionality of the prototype, a model chemiluminescence ELISA was performed. The performance of the integrated optical detection in the point-of-care prototype is equal to that obtained with traditional bench-top instrumentation. The photodiode signals were acquired, displayed and processed by a simple graphical user interface using a computer connected to the microcontroller through USB. The prototype performed integrated chemiluminescence ELISA detection in about 15 min with a limit-of-detection of ≈2 nM with an antibody-antigen affinity constant of ≈2×10(7) M(-1). PMID:24607579

  5. Electrochemical detection of point mutation based on surface hybridization assay conjugated allele-specific polymerase chain reaction.

    PubMed

    Huang, Yong; Zhu, Jing; Li, Guiyin; Chen, Zhencheng; Jiang, Jian-Hui; Shen, Guo-Li; Yu, Ru-Qin

    2013-04-15

    In this work, we developed an electrochemical detection method based on allele-specific polymerase chain reaction (AS-PCR) and surface hybridization assay technique for the point mutation detection. A high-fidelity Vent(R)™(exo⁻) DNA polymerase, which eliminated the 3'→5' proofreading exonuclease activity by genetical engineering, was used to discriminate and extend the detection probe that perfectly matched with mutant target DNA and generate a redox-active DNA replica which folded into a molecular beacon structure by intramolecular hybridization. After hybridized with capture probe modified on gold electrode by self-assembly reaction, the redox tags can be closed to electrode, resulting in a substantial current with the maximized sensitivity for point mutation analysis. However, when there is an allele mismatch in the wild target DNA, and so no the redox-active replica DNA can be obtained. In this case, no remarkable current signal can be trigged. The proposed approach has been successfully implemented for the identification of single base mutation at the -28 position in human β-globin gene with a detection limit of 0.5 fM, demonstrating that this method provides a highly specific, sensitive and cost-efficient approach for point mutation detection.

  6. Airborne validation of ground-object detection from polarized neutral-point atmosphere.

    PubMed

    Yang, Shang-qiang; Guan, Gui-xia; Zhao, Hai-meng; Zhao, Hong-ying; Yang, Bin; Zhang, Wen-kai; Tan, Xiang; Wu, Tai-xia; Yan, Lei

    2013-09-01

    Based on the object's polarization effects, polarization is a newly emerging method in the field of remote sensing. Both objects and atmosphere have polarization effects, however, the atmosphere's polarization effects are much stronger than that of objects'. Consequently, atmosphere polarization effects will interfere or even cover objects' when observing with sensors. How to maximally eliminate the polarized effects generated by the atmosphere is a crucial problem in polarization remote sensing. Atmospheric neutral point is an area where the degree of atmosphere polarization is near to zero; therefore, if sensors are set up in this area, atmosphere polarization would be greatly eliminated, which is the main content of separating the effects between objects and atmosphere by its neutral point method. In this paper, after processing and analyzing the experimental data got from the first polarization remote sensing flight experiment with atmosphere neutral point, the degree of polarization images captured in neutral and non-neutral point area were obtained, and it can be seen that the main value of polarized degree of images got in neutral point area was obviously smaller than that in non-neutral point area. The results showed that the theory mentioned above was logical and practical. An innovation in our study is that the requirements needed in polarization remote sensing flight with neutral point were clarified. In the meantime, a qualitative conclusion was drawn that observing with longer wavelength is more applicable to polarization remote sensing. PMID:24369665

  7. SDTP: a robust method for interest point detection on 3D range images

    NASA Astrophysics Data System (ADS)

    Wang, Shandong; Gong, Lujin; Zhang, Hui; Zhang, Yongjie; Ren, Haibing; Rhee, Seon-Min; Lee, Hyong-Euk

    2013-12-01

    In fields of intelligent robots and computer vision, the capability to select a few points representing salient structures has always been focused and investigated. In this paper, we present a novel interest point detector for 3D range images, which can be used with good results in applications of surface registration and object recognition. A local shape description around each point in the range image is firstly constructed based on the distribution map of the signed distances to the tangent plane in its local support region. Using this shape description, the interest value is computed for indicating the probability of a point being the interest point. Lastly a Non-Maxima Suppression procedure is performed to select stable interest points on positions that have large surface variation in the vicinity. Our method is robust to noise, occlusion and clutter, which can be seen from the higher repeatability values compared with the state-of-the-art 3D interest point detectors in experiments. In addition, the method can be implemented easily and requires low computation time.

  8. The Pan Genera Detection immunoassay: a novel point-of-issue method for detection of bacterial contamination in platelet concentrates.

    PubMed

    Vollmer, Tanja; Hinse, Dennis; Kleesiek, Knut; Dreier, Jens

    2010-10-01

    Bacterial contamination of platelet concentrates (PCs) still represents an ongoing risk in transfusion-transmitted sepsis. Recently the Pan Genera Detection (PGD) system was developed and FDA licensed for screening of bacterial contamination of PCs directly prior to transfusion. The test principle is based on the immunological detection of lipopolysaccharide (for Gram-negative bacteria) or lipoteichoic acid (for Gram-positive bacteria). In the present study we analyzed the applicability of this method with regard to detection limit, practicability, implementation, and performance. PCs were spiked with Staphylococcus aureus, Bacillus subtilis, and five different Klebsiella pneumoniae strains, as well as eight different Escherichia coli strains. The presence of bacteria was assessed by the PGD immunoassay, and bacteria were enumerated by plating cultures. Application of the PGD immunoassay showed that it is a rapid test with a short hands-on time for sample processing and no demand for special technical equipment and instrument operation. The lower detection limits of the assay for Gram-positive bacteria showed a good agreement with the manufacturer's specifications (8.2 × 10(3) to 5.5 × 10(4) CFU/ml). For some strains of K. pneumoniae and E. coli, the PGD test showed analytical sensitivities (>10(6) CFU/ml) that were divergent from the designated values (K. pneumoniae, 2.0 × 10(4) CFU/ml; E. coli, 2.8 × 10(4) CFU/ml). Result interpretation is sometimes difficult due to very faint bands. In conclusion, our study demonstrates that the PGD immunoassay is an easy-to-perform bedside test for the detection of bacterial contamination in PCs. However, to date there are some shortcomings in the interpretation of results and in the detection limits for some strains of Gram-negative bacteria. PMID:20702673

  9. Emergency Point-of-Care Ultrasound Detection of Cancer in the Pediatric Emergency Department.

    PubMed

    Jamjoom, Roaa S; Etoom, Yousef; Solano, Tanya; Desjardins, Marie-Pier; Fischer, Jason W

    2015-08-01

    The use of point-of-care ultrasound in the pediatric emergency department is evolving beyond conventional applications as users become more expert with the technology. In this case series, we describe the potential utility of recognizing abnormal anatomy to impact care in the context of possible cancer in pediatric patients. We describe 4 patients with Langerhans histiocytosis, neuroblastoma, Wilms tumor, and rhabdomyosarcoma, in which point-of-care ultrasound was used to facilitate the diagnoses.

  10. Evaluation of a Rapid Lateral Flow Point-of-Care Test for Detection of Cryptosporidium

    PubMed Central

    Fleece, Molly E.; Heptinstall, Jack; Khan, Shaila S.; Kabir, Mamum; Herbein, Joel; Haque, Rashidul; Petri, William A.

    2016-01-01

    A new rapid lateral flow fecal antigen detection test for Cryptosporidium was evaluated using diarrheal stool samples from a cohort of children in Bangladesh. The test had a sensitivity of 100% and a specificity of 94% when compared with enzyme-linked immunosorbent assay antigen detection. PMID:27573629

  11. Road Signs Detection and Recognition Utilizing Images and 3d Point Cloud Acquired by Mobile Mapping System

    NASA Astrophysics Data System (ADS)

    Li, Y. H.; Shinohara, T.; Satoh, T.; Tachibana, K.

    2016-06-01

    High-definition and highly accurate road maps are necessary for the realization of automated driving, and road signs are among the most important element in the road map. Therefore, a technique is necessary which can acquire information about all kinds of road signs automatically and efficiently. Due to the continuous technical advancement of Mobile Mapping System (MMS), it has become possible to acquire large number of images and 3d point cloud efficiently with highly precise position information. In this paper, we present an automatic road sign detection and recognition approach utilizing both images and 3D point cloud acquired by MMS. The proposed approach consists of three stages: 1) detection of road signs from images based on their color and shape features using object based image analysis method, 2) filtering out of over detected candidates utilizing size and position information estimated from 3D point cloud, region of candidates and camera information, and 3) road sign recognition using template matching method after shape normalization. The effectiveness of proposed approach was evaluated by testing dataset, acquired from more than 180 km of different types of roads in Japan. The results show a very high success in detection and recognition of road signs, even under the challenging conditions such as discoloration, deformation and in spite of partial occlusions.

  12. Archival Legacy Investigations of Circumstellar Environments (ALICE): Statistical assessment of point source detections

    NASA Astrophysics Data System (ADS)

    Choquet, Élodie; Pueyo, Laurent; Soummer, Rémi; Perrin, Marshall D.; Hagan, J. Brendan; Gofas-Salas, Elena; Rajan, Abhijith; Aguilar, Jonathan

    2015-09-01

    The ALICE program, for Archival Legacy Investigation of Circumstellar Environment, is currently conducting a virtual survey of about 400 stars, by re-analyzing the HST-NICMOS coronagraphic archive with advanced post-processing techniques. We present here the strategy that we adopted to identify detections and potential candidates for follow-up observations, and we give a preliminary overview of our detections. We present a statistical analysis conducted to evaluate the confidence level on these detection and the completeness of our candidate search.

  13. Algorithms for Collision Detection Between a Point and a Moving Polygon, with Applications to Aircraft Weather Avoidance

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony; Hagen, George

    2016-01-01

    This paper proposes mathematical definitions of functions that can be used to detect future collisions between a point and a moving polygon. The intended application is weather avoidance, where the given point represents an aircraft and bounding polygons are chosen to model regions with bad weather. Other applications could possibly include avoiding other moving obstacles. The motivation for the functions presented here is safety, and therefore they have been proved to be mathematically correct. The functions are being developed for inclusion in NASA's Stratway software tool, which allows low-fidelity air traffic management concepts to be easily prototyped and quickly tested.

  14. The Apache Point Observatory Lunar Laser-ranging Operation: Instrument Description and First Detections

    SciTech Connect

    Murphy, TW; Adelberger, Eric G.; Battat, J.; Carey, LN; Hoyle, Charles D.; LeBlanc, P.; Michelsen, EL; Nordtvedt, K.; Orin, AE; Strasburg, Jana D.; Stubbs, CW; Swanson, HE; Williams, E.

    2008-01-01

    A next-generation lunar laser ranging apparatus using the 3.5 m telescope at the Apache Point Observatory in southern New Mexico has begun science operation. APOLLO (the Apache Point Observatory Lunar Laser-ranging Operation) has achieved one-millimeter range precision to the moon which should lead to aproximately one-orderof-magnitude improvements in the precision of several tests of fundamental properties of gravity. We briefly motivate the scientific goals, and then give a detailed discussion of the APOLLO instrumentation.

  15. A Novel Point-of-Care BioNanoSensor for Rapid HIV Detection and Treatment Monitoring

    PubMed Central

    Rozmyslowicz, Tomasz; deSa, Johann; Lec, Ryszard; Gaulton, Glen N

    2015-01-01

    We report here a new diagnostic approach to the direct detection of HIV in blood or other body fluids that is rapid, sensitive and potentially applicable in a point-of-care setting. The approach follows on the development of a novel BioNanoSensor (BNS) device that utilizes piezoelectric technology to detect the presence of the HIV surface glycoprotein gp120 in a nanoscale format. The detection range of the BNS device for the biomarker gp120 displayed a low-end sensitivity of 6.5×104 HIV viral particles/ml, while using a small fluid sample (5 µl) and with a reaction time of less then 30 seconds. Performance of this device indicated that the BNS has utility for direct detection of HIV particles prior to, and independent from, antibody formation. Accordingly, this device holds utility to monitor the status of HIV infection both early after exposure to virus as well as during chronic HIV infection. The BNS parameters of small sample volume, compact device size, and detection sensitivity indicate that the BNS is potentially useful in the point-of-care and/or home setting for monitoring decisions regarding HIV treatment on a real-time basis. PMID:26457228

  16. Detecting Differential Item Functioning of Polytomous Items for an Ideal Point Response Process

    ERIC Educational Resources Information Center

    Wang, Wei; Tay, Louis; Drasgow, Fritz

    2013-01-01

    There has been growing use of ideal point models to develop scales measuring important psychological constructs. For meaningful comparisons across groups, it is important to identify items on such scales that exhibit differential item functioning (DIF). In this study, the authors examined several methods for assessing DIF on polytomous items…

  17. Young Infants Detect the Direction of Biological Motion in Point-Light Displays

    ERIC Educational Resources Information Center

    Kuhlmeier, Valerie A.; Troje, Nikolaus F.; Lee, Vivian

    2010-01-01

    In the present study, we examined if young infants can extract information regarding the directionality of biological motion. We report that 6-month-old infants can differentiate leftward and rightward motions from a movie depicting the sagittal view of an upright human point-light walker, walking as if on a treadmill. Inversion of the stimuli…

  18. Detecting Blending End-Point Using Mean Squares Successive Difference Test and Near-Infrared Spectroscopy.

    PubMed

    Khorasani, Milad; Amigo, José M; Bertelsen, Poul; Van Den Berg, Frans; Rantanen, Jukka

    2015-08-01

    An algorithm based on mean squares successive difference test applied to near-infrared and principal component analysis scores was developed to monitor and determine the blending profile and to assess the end-point in the statistical stabile phase. Model formulations consisting of an active compound (acetylsalicylic acid), together with microcrystalline cellulose and two grades of calcium carbonate with dramatically different particle shapes, were prepared. The formulation comprising angular-shaped calcium carbonate reached blending end-point slower when compared with the formulation comprising equant-shaped calcium carbonate. Utilizing the ring shear test, this distinction in end-point could be related to the difference in flowability of the formulations. On the basis of the two model formulations, a design of experiments was conducted to characterize the blending process by studying the effect of CaCO3 grades and fill level of the bin on blending end-point. Calcium carbonate grades, fill level, and their interaction were shown to have a significant impact on the blending process. PMID:26094601

  19. A multiplexed nucleic acid microsystem for point-of-care detection of HIV co-infection with MTB and PCP.

    PubMed

    Xu, Lingjia; Kong, Jilie

    2013-12-15

    Many individuals infected with the human immunodeficiency virus (HIV), especially children in African countries, die of co-infections with Mycobacterium tuberculosis (MTB) (coinfection rate: 50%) or Pneumocystis carinii pneumonia (PCP) (coinfection rate: 81%). The present proposal describes a rapid, portable, low-cost, multiplexed point-of-care diagnostic technique for simultaneously detecting HIV, MTB, and PCP. This technique incorporates a creative micro-device (hardware) and a loop-mediated isothermal amplification strategy (software). PMID:24209377

  20. Practicability of detecting somatic point mutation from RNA high throughput sequencing data.

    PubMed

    Sheng, Quanhu; Zhao, Shilin; Li, Chung-I; Shyr, Yu; Guo, Yan

    2016-05-01

    Traditionally, somatic mutations are detected by examining DNA sequence. The maturity of sequencing technology has allowed researchers to screen for somatic mutations in the whole genome. Increasingly, researchers have become interested in identifying somatic mutations through RNAseq data. With this motivation, we evaluated the practicability of detecting somatic mutations from RNAseq data. Current somatic mutation calling tools were designed for DNA sequencing data. To increase performance on RNAseq data, we developed a somatic mutation caller GLMVC based on bias reduced generalized linear model for both DNA and RNA sequencing data. Through comparison with MuTect and Varscan we showed that GLMVC performed better for somatic mutation detection using exome sequencing or RNAseq data. GLMVC is freely available for download at the following website: https://github.com/shengqh/GLMVC/wiki.

  1. D Geological Outcrop Characterization: Automatic Detection of 3d Planes (azimuth and Dip) Using LiDAR Point Clouds

    NASA Astrophysics Data System (ADS)

    Anders, K.; Hämmerle, M.; Miernik, G.; Drews, T.; Escalona, A.; Townsend, C.; Höfle, B.

    2016-06-01

    Terrestrial laser scanning constitutes a powerful method in spatial information data acquisition and allows for geological outcrops to be captured with high resolution and accuracy. A crucial aspect for numerous geologic applications is the extraction of rock surface orientations from the data. This paper focuses on the detection of planes in rock surface data by applying a segmentation algorithm directly to a 3D point cloud. Its performance is assessed considering (1) reduced spatial resolution of data and (2) smoothing in the course of data pre-processing. The methodology is tested on simulations of progressively reduced spatial resolution defined by varying point cloud density. Smoothing of the point cloud data is implemented by modifying the neighborhood criteria during normals estima-tion. The considerable alteration of resulting planes emphasizes the influence of smoothing on the plane detection prior to the actual segmentation. Therefore, the parameter needs to be set in accordance with individual purposes and respective scales of studies. Fur-thermore, it is concluded that the quality of segmentation results does not decline even when the data volume is significantly reduced down to 10%. The azimuth and dip values of individual segments are determined for planes fit to the points belonging to one segment. Based on these results, azimuth and dip as well as strike character of the surface planes in the outcrop are assessed. Thereby, this paper contributes to a fully automatic and straightforward workflow for a comprehensive geometric description of outcrops in 3D.

  2. Optical detection of melting point depression for silver nanoparticles via in situ real time spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Little, S. A.; Begou, T.; Collins, R. W.; Marsillac, S.

    2012-01-01

    Silver nanoparticle films were deposited by sputtering at room temperature and were annealed while monitoring by real time spectroscopic ellipsometry (SE). The nanoparticle dielectric functions (0.75 eV-6.5 eV) obtained by SE were modeled using Lorentz and generalized oscillators for the nanoparticle plasmon polariton (NPP) and interband transitions, respectively. The nanoparticle melting point could be identified from variations in the oscillator parameters during annealing, and this identification was further confirmed after cooling through significant, irreversible changes in these parameters relative to the as-deposited film. The variation in melting point with physical thickness, and thus average nanoparticle diameter, as measured by SE enables calculation of the surface energy density.

  3. Point decoration of silicon nanowires: an approach toward single-molecule electrical detection.

    PubMed

    Wang, Jindong; Shen, Fangxia; Wang, Zhenxing; He, Gen; Qin, Jinwen; Cheng, Nongyi; Yao, Maosheng; Li, Lidong; Guo, Xuefeng

    2014-05-12

    Probing interactions of biological systems at the molecular level is of great importance to fundamental biology, diagnosis, and drug discovery. A rational bioassay design of lithographically integrating individual point scattering sites into electrical circuits is capable of realizing real-time, label-free biodetection of influenza H1N1 viruses with single-molecule sensitivity and high selectivity by using silicon nanowires as local reporters in combination with microfluidics. This nanocircuit-based architecture is complementary to more conventional optical techniques, but has the advantages of no bleaching problems and no fluorescent labeling. These advantages offer a promising platform for exploring dynamics of stochastic processes in biological systems and gaining information from genomics to proteomics to improve accurate molecular and even point-of-care clinical diagnosis.

  4. Detecting long-term changes in point-source fossil CO2 emissions with tree ring archives

    NASA Astrophysics Data System (ADS)

    Keller, Elizabeth D.; Turnbull, Jocelyn C.; Norris, Margaret W.

    2016-05-01

    We examine the utility of tree ring 14C archives for detecting long-term changes in fossil CO2 emissions from a point source. Trees assimilate carbon from the atmosphere during photosynthesis, in the process faithfully recording the average atmospheric 14C content in each new annual tree ring. Using 14C as a proxy for fossil CO2, we examine interannual variability over six years of fossil CO2 observations between 2004-2005 and 2011-2012 from two trees growing near the Kapuni Gas Treatment Plant in rural Taranaki, New Zealand. We quantify the amount of variability that can be attributed to transport and meteorology by simulating constant point-source fossil CO2 emissions over the observation period with the atmospheric transport model WindTrax. We compare model simulation results to observations and calculate the amount of change in emissions that we can detect with new observations over annual or multi-year time periods, given both the measurement uncertainty of 1ppm and the modelled variation in transport. In particular, we ask, what is the minimum amount of change in emissions that we can detect using this method, given a reference period of six years? We find that changes of 42 % or more could be detected in a new sample from one year at the same observation location or 22 % in the case of four years of new samples. This threshold is reduced and the method becomes more practical the more the size of the signal increases. For point sources 10 times larger than the Kapuni plant (a more typical size for power plants worldwide), it would be possible to detect sustained emissions changes on the order of 10 %, given suitable meteorology and observations.

  5. Point-of-care ultrasound detection of tracheal wall thickening caused by smoke inhalation.

    PubMed

    Kameda, Toru; Fujita, Masato

    2014-01-01

    Smoke inhalation is the leading cause of death due to fires. When a patient presents with smoke inhalation, prompt assessment of the airway and breathing is necessary. Point-of-care ultrasonography (US) is used for the rapid assessment of critically ill or injured patients. We herein present a case report of a 54-year-old male who was transferred to the emergency department with shortness of breath, coughing, carbonaceous sputa, and rhinorrhea after inhaling smoke caused by a fire in his locked bedroom. He had no surface burns on the face and no edema or erosion in the oral cavity. He had hoarseness without stridor. His breath sounds were positive for expiratory wheezes. Laryngoscopy showed light edema and erosive findings on the supraglottic region. Bedside point-of-care US revealed hypoechoic thickening of the tracheal wall. The thickening was confirmed by a computed tomographic scan. The patient was carefully monitored with preparation for emergency airway management and was treated with supplemental oxygen and an aerosolized beta-2 adrenergic agonist in the intensive care unit. The symptoms were subsequently relieved, and reexamination by US after 2 days showed remission of the wall thickening. Point-of-care US may therefore be a useful modality for the rapid diagnosis and effective follow-up of tracheal wall thickening caused by smoke inhalation. PMID:25097745

  6. Methods for point-of-care detection of nucleic acid in a sample

    DOEpatents

    Bearinger, Jane P.; Dugan, Lawrence C.

    2015-12-29

    Provided herein are methods and apparatus for detecting a target nucleic acid in a sample and related methods and apparatus for diagnosing a condition in an individual. The condition is associated with presence of nucleic acid produced by certain pathogens in the individual.

  7. Apparatus for point-of-care detection of nucleic acid in a sample

    DOEpatents

    Bearinger, Jane P.; Dugan, Lawrence C.

    2016-04-19

    Provided herein are methods and apparatus for detecting a target nucleic acid in a sample and related methods and apparatus for diagnosing a condition in an individual. The condition is associated with presence of nucleic acid produced by certain pathogens in the individual.

  8. Trackline and point detection probabilities for acoustic surveys of Cuvier's and Blainville's beaked whales.

    PubMed

    Barlow, Jay; Tyack, Peter L; Johnson, Mark P; Baird, Robin W; Schorr, Gregory S; Andrews, Russel D; Aguilar de Soto, Natacha

    2013-09-01

    Acoustic survey methods can be used to estimate density and abundance using sounds produced by cetaceans and detected using hydrophones if the probability of detection can be estimated. For passive acoustic surveys, probability of detection at zero horizontal distance from a sensor, commonly called g(0), depends on the temporal patterns of vocalizations. Methods to estimate g(0) are developed based on the assumption that a beaked whale will be detected if it is producing regular echolocation clicks directly under or above a hydrophone. Data from acoustic recording tags placed on two species of beaked whales (Cuvier's beaked whale-Ziphius cavirostris and Blainville's beaked whale-Mesoplodon densirostris) are used to directly estimate the percentage of time they produce echolocation clicks. A model of vocal behavior for these species as a function of their diving behavior is applied to other types of dive data (from time-depth recorders and time-depth-transmitting satellite tags) to indirectly determine g(0) in other locations for low ambient noise conditions. Estimates of g(0) for a single instant in time are 0.28 [standard deviation (s.d.) = 0.05] for Cuvier's beaked whale and 0.19 (s.d. = 0.01) for Blainville's beaked whale.

  9. ORD research and results using biological end points to detect exposures to contaminants of emerging concern

    EPA Science Inventory

    For the past nine years the Ecological Exposure Research Division (EERD) has been developing methods for the assessment of EDCs and other contaminants of emerging concern (CECs). These methods include genomic techniques for detecting the presence and potential exposure to human p...

  10. Application of flat panel OLED display technology for the point-of-care detection of circulating cancer biomarkers.

    PubMed

    Katchman, Benjamin A; Smith, Joseph T; Obahiagbon, Uwadiae; Kesiraju, Sailaja; Lee, Yong-Kyun; O'Brien, Barry; Kaftanoglu, Korhan; Blain Christen, Jennifer; Anderson, Karen S

    2016-07-04

    Point-of-care molecular diagnostics can provide efficient and cost-effective medical care, and they have the potential to fundamentally change our approach to global health. However, most existing approaches are not scalable to include multiple biomarkers. As a solution, we have combined commercial flat panel OLED display technology with protein microarray technology to enable high-density fluorescent, programmable, multiplexed biorecognition in a compact and disposable configuration with clinical-level sensitivity. Our approach leverages advances in commercial display technology to reduce pre-functionalized biosensor substrate costs to pennies per cm(2). Here, we demonstrate quantitative detection of IgG antibodies to multiple viral antigens in patient serum samples with detection limits for human IgG in the 10 pg/mL range. We also demonstrate multiplexed detection of antibodies to the HPV16 proteins E2, E6, and E7, which are circulating biomarkers for cervical as well as head and neck cancers.

  11. The 3D Hough Transform for plane detection in point clouds: A review and a new accumulator design

    NASA Astrophysics Data System (ADS)

    Borrmann, Dorit; Elseberg, Jan; Lingemann, Kai; Nüchter, Andreas

    2011-03-01

    The Hough Transform is a well-known method for detecting parameterized objects. It is the de facto standard for detecting lines and circles in 2-dimensional data sets. For 3D it has attained little attention so far. Even for the 2D case high computational costs have lead to the development of numerous variations for the Hough Transform. In this article we evaluate different variants of the Hough Transform with respect to their applicability to detect planes in 3D point clouds reliably. Apart from computational costs, the main problem is the representation of the accumulator. Usual implementations favor geometrical objects with certain parameters due to uneven sampling of the parameter space. We present a novel approach to design the accumulator focusing on achieving the same size for each cell and compare it to existing designs. [Figure not available: see fulltext.

  12. Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

    PubMed

    Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

    2016-05-01

    The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

    PubMed

    Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

    2016-05-01

    The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26936529

  14. Heteroduplex analysis of the dystrophin gene: Application to point mutation and carrier detection

    SciTech Connect

    Prior, T.W.; Papp, A.C.; Snyder, P.J.; Sedra, M.S.; Western, L.M.; Bartolo, C.; Mendell, J.R.; Moxley, R.T.

    1994-03-01

    Approximately one-third of Duchenne muscular dystrophy patients have undefined mutations in the dystrophin gene. For carrier and prenatal studies in families without detectable mutations, the indirect restriction fragment length polymorphism linkage approach is used. Using a multiplex amplification and heteroduplex analysis of dystrophin exons, the authors identified nonsense mutations in two DMD patients. Although the nonsense mutations are predicted to severely truncate the dystrophin protein, both patients presented with mild clinical courses of the disease. As a result of identifying the mutation in the affected boys, direct carrier studies by heteroduplex analysis were extended to other relatives. The authors conclude that the technique is not only ideal for mutation detection but is also useful for diagnostic testing. 29 refs., 4 figs.

  15. Magnetic droplet manipulation platforms for nucleic acid detection at the point of care.

    PubMed

    Shin, Dong Jin; Wang, Tza-Huei

    2014-11-01

    This review summarizes recent developments in the use of magnetically actuated droplets in point-of-care molecular diagnostic platforms. We discuss the fundamentals of magnetic droplet manipulation and the various modes of actuation. The balance of forces acting on a droplet during transport and particle extraction, as well as the devices and instrumentation developed to perform these operations will be presented and discussed. Furthermore, we review some of the recent advances on the diagnostic applications of platforms utilizing magnetic manipulation for genetic assessment of biological samples.

  16. A Novel Point-of-Care Biomarker Recognition Method: Validation by Detecting Marker for Diabetic Nephropathy

    PubMed Central

    Pentyala, Sahana; Muller, John; Tumillo, Thomas; Roy, Avijit; Mysore, Pooja; Pentyala, Srinivas

    2015-01-01

    Biological fluid collection to identify and analyze different disease markers is a routine and normal procedure in health care settings. Body fluids are as varied as urine, blood, mucus, cerebrospinal fluid (CSF), tears, semen, etc. The volumes of the collected fluids range from micro liters (e.g., tears, CSF) to tens and hundreds of milliliters (blood, urine, etc.). In some manifestations, a disease marker (particularly protein markers) can occur in trace amounts, yet the fluids collected are in large volumes. To identify these trace markers, cumbersome methods, expensive instruments, and trained personnel are required. We developed an easy method to rapidly capture, concentrate, and identify protein markers in large volumes of test fluids. This method involves the utilization of two antibodies recognizing two different epitopes of the protein biomarker. Antibody-1 helps to capture and concentrate the biomarker and Antibody-2 adsorbed or conjugated to nanogold beads will detect the biomarker. This method was validated in capturing and detecting lipocalin type prostaglandin-D2 synthase, a marker in urine that implicates diabetic nephropathy. A one-step collection, concentration, and detection device was designed based on this method. This device can replace many of the normal body fluid collection devices such as tubes and containers. A one-step fluid collection and biomarker capture and concentration device for rapid diagnosis of diseases has tremendous advantage in terms of cost and providing timely results. PMID:26854148

  17. Integrated Mueller-matrix near-infrared imaging and point-wise spectroscopy improves colonic cancer detection

    PubMed Central

    Wang, Jianfeng; Zheng, Wei; Lin, Kan; Huang, Zhiwei

    2016-01-01

    We report the development and implementation of a unique integrated Mueller-matrix (MM) near-infrared (NIR) imaging and Mueller-matrix point-wise diffuse reflectance (DR) spectroscopy technique for improving colonic cancer detection and diagnosis. Point-wise MM DR spectra can be acquired from any suspicious tissue areas indicated by MM imaging. A total of 30 paired colonic tissue specimens (normal vs. cancer) were measured using the integrated MM imaging and point-wise MM DR spectroscopy system. Polar decomposition algorithms are employed on the acquired images and spectra to derive three polarization metrics including depolarization, diattentuation and retardance for colonic tissue characterization. The decomposition results show that tissue depolarization and retardance are significantly decreased (p<0.001, paired 2-sided Student’s t-test, n = 30); while the tissue diattentuation is significantly increased (p<0.001, paired 2-sided Student’s t-test, n = 30) associated with colonic cancer. Further partial least squares discriminant analysis (PLS-DA) and leave-one tissue site-out, cross validation (LOSCV) show that the combination of the three polarization metrics provide the best diagnostic accuracy of 95.0% (sensitivity: 93.3%, and specificity: 96.7%) compared to either of the three polarization metrics (sensitivities of 93.3%, 83.3%, and 80.0%; and specificities of 90.0%, 96.7%, and 80.0%, respectively, for the depolarization, diattentuation and retardance metrics) for colonic cancer detection. This work suggests that the integrated MM NIR imaging and point-wise MM NIR diffuse reflectance spectroscopy has the potential to improve the early detection and diagnosis of malignant lesions in the colon. PMID:27446640

  18. a Graph Based Model for the Detection of Tidal Channels Using Marked Point Processes

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Rottensteiner, F.; Soergel, U.; Heipke, C.

    2015-08-01

    In this paper we propose a new method for the automatic extraction of tidal channels in digital terrain models (DTM) using a sampling approach based on marked point processes. In our model, the tidal channel system is represented by an undirected, acyclic graph. The graph is iteratively generated and fitted to the data using stochastic optimization based on a Reversible Jump Markov Chain Monte Carlo (RJMCMC) sampler and simulated annealing. The nodes of the graph represent junction points of the channel system and the edges straight line segments with a certain width in between. In each sampling step, the current configuration of nodes and edges is modified. The changes are accepted or rejected depending on the probability density function for the configuration which evaluates the conformity of the current status with a pre-defined model for tidal channels. In this model we favour high DTM gradient magnitudes at the edge borders and penalize a graph configuration consisting of non-connected components, overlapping segments and edges with atypical intersection angles. We present the method of our graph based model and show results for lidar data, which serve of a proof of concept of our approach.

  19. Comparative classification analysis of post-harvest growth detection from terrestrial LiDAR point clouds in precision agriculture

    NASA Astrophysics Data System (ADS)

    Koenig, Kristina; Höfle, Bernhard; Hämmerle, Martin; Jarmer, Thomas; Siegmann, Bastian; Lilienthal, Holger

    2015-06-01

    In precision agriculture, detailed geoinformation on plant and soil properties plays an important role, e.g., in crop protection or the application of fertilizers. This paper presents a comparative classification analysis for post-harvest growth detection using geometric and radiometric point cloud features of terrestrial laser scanning (TLS) data, considering the local neighborhood of each point. Radiometric correction of the TLS data was performed via an empirical range-correction function derived from a field experiment. Thereafter, the corrected amplitude and local elevation features were explored regarding their importance for classification. For the comparison, tree induction, Naive Bayes, and k-Means-derived classifiers were tested for different point densities to distinguish between ground and post-harvest growth. The classification performance was validated against highly detailed RGB reference images and the red edge normalized difference vegetation index (NDVI705), derived from a hyperspectral sensor. Using both geometric and radiometric features, we achieved a precision of 99% with the tree induction. Compared to the reference image classification, the calculated post-harvest growth coverage map reached an accuracy of 80%. RGB and LiDAR-derived coverage showed a polynomial correlation to NDVI705 of degree two with R2 of 0.8 and 0.7, respectively. Larger post-harvest growth patches (>10 × 10 cm) could already be detected by a point density of 2 pts./0.01 m2. The results indicate a high potential of radiometric and geometric LiDAR point cloud features for the identification of post-harvest growth using tree induction classification. The proposed technique can potentially be applied over larger areas using vehicle-mounted scanners.

  20. Fluorescence molecular probes for sensitive point detection of amyloid fibrils and protofibrils

    NASA Astrophysics Data System (ADS)

    Lindgren, Mikael; Jonsson, Per; Sörgjerd, Karin; Hammarström, Per

    2005-10-01

    Protein based infections such as prion diseases have lately attracted a large amount of interest, primarily due to the Mad Cow Epidemic in Great Britain, and the increase of Alzheimer's disease and related diseases in the ageing Western society. Infective proteins are very stable and almost untraceable prior to infection making them ideal as biological weapons. Particularly if the used agent is of human origin, the immunoresponse can be avoided, leaving no trace of the infectious agent. The transient nature of infectious oligomeric intermediates of misfolded proteins or peptide fragments that later matures into fibrillar aggregates makes them hard to study, and methods to detect and study these species are sparse. There exist a number of fluorescent probes that bind specifically to protein amyloidic structures. Thioflavins (ThT, ThS), Congo and Nile red, 4-(dicyanovinyl)-julolidine (DCVJ), as well as derivatives amino-8-naphtalene sulphonate (ANS, Bis-ANS) which are known to bind to the fibrillar or pre-fibrillar states with dissociation constants of typically 1 - 20 μM. Here, transthyretin (TTR), insulin and lysozyme were used as model proteins to detect different amyloid precursor states for diseases such as senile systemic amyloidosis, familial amyloidotic polyneuropathy (FAP) and iatrogenic amyloidosis. Specifically, the probes were employed in static assays to characterize protofibrillar and mature amyloid fibrillar states using steady state and time-resolved fluorescence techniques. Particularly, we investigate and report on the possibility to detect protofibrillar states at low concentration levels using modern fluorescence array detector systems in conjunction with lasers operating in the blue or ultraviolett wavelengths as excitation source. Results of ANS, ThT and a ThT analogue (abbreviated ThC) are discussed.

  1. Chemical and explosives point detection through opaque containers using spatially offset Raman spectroscopy (SORS)

    NASA Astrophysics Data System (ADS)

    Loeffen, Paul W.; Maskall, Guy; Bonthron, Stuart; Bloomfield, Matthew; Tombling, Craig; Matousek, Pavel

    2011-05-01

    Spatially Offset Raman Spectroscopy (SORS) is a novel technique used to identify the chemical Raman signature of threat materials within a few seconds through common non-metallic containers, including those containers which may not yield to inspection by conventional backscatter Raman. In particular, some opaque plastic containers and coloured glass bottles can be difficult to analyze using conventional backscatter Raman because the signal from the contents is often overwhelmed by the much stronger Raman signal and/or fluorescence originating from the container itself. SORS overcomes these difficulties and generates clean Raman spectra from both the container and the contents with no prior knowledge of either. This is achieved by making two, or more, Raman measurements at various offsets between the collection and illumination areas, each containing different proportions of the fingerprint signals from the container and content materials. Using scaled subtraction, or multivariate statistical methods, the two orthogonal signals can be separated numerically, thereby providing a clean Raman spectrum of the contents without contamination from the container. Consequently, SORS promises to significantly improve threat detection capability and decrease the falsealarm rate compared with conventional Raman spectroscopy making it considerably more suitable as an alarm resolution methodology (e.g. at airports). In this paper, the technique and method are described and a study of offset value optimization is described illustrating the difference between one and two fixed spatial offsets. It is concluded that two fixed offsets yield an improvement in the SORS measurement which will help maximize the threat detection capability.

  2. Multi-point accelerometric detection and principal component analysis of heart sounds.

    PubMed

    De Panfilis, S; Moroni, C; Peccianti, M; Chiru, O M; Vashkevich, V; Parisi, G; Cassone, R

    2013-03-01

    Heart sounds are a fundamental physiological variable that provide a unique insight into cardiac semiotics. However a deterministic and unambiguous association between noises in cardiac dynamics is far from being accomplished yet due to many and different overlapping events which contribute to the acoustic emission. The current computer-based capacities in terms of signal detection and processing allow one to move from the standard cardiac auscultation, even in its improved forms like electronic stethoscopes or hi-tech phonocardiography, to the extraction of information on the cardiac activity previously unexplored. In this report, we present a new equipment for the detection of heart sounds, based on a set of accelerometric sensors placed in contact with the chest skin on the precordial area, and are able to measure simultaneously the vibration induced on the chest surface by the heart's mechanical activity. By utilizing advanced algorithms for the data treatment, such as wavelet decomposition and principal component analysis, we are able to condense the spatially extended acoustic information and to provide a synthetical representation of the heart activity. We applied our approach to 30 adults, mixed per gender, age and healthiness, and correlated our results with standard echocardiographic examinations. We obtained a 93% concordance rate with echocardiography between healthy and unhealthy hearts, including minor abnormalities such as mitral valve prolapse.

  3. Effect of time-of-flight and point spread function modeling on detectability of myocardial defects in PET

    SciTech Connect

    Schaefferkoetter, Joshua; Ouyang, Jinsong; Rakvongthai, Yothin; El Fakhri, Georges; Nappi, Carmela

    2014-06-15

    Purpose: A study was designed to investigate the impact of time-of-flight (TOF) and point spread function (PSF) modeling on the detectability of myocardial defects. Methods: Clinical FDG-PET data were used to generate populations of defect-present and defect-absent images. Defects were incorporated at three contrast levels, and images were reconstructed by ordered subset expectation maximization (OSEM) iterative methods including ordinary Poisson, alone and with PSF, TOF, and PSF+TOF. Channelized Hotelling observer signal-to-noise ratio (SNR) was the surrogate for human observer performance. Results: For three iterations, 12 subsets, and no postreconstruction smoothing, TOF improved overall defect detection SNR by 8.6% as compared to its non-TOF counterpart for all the defect contrasts. Due to the slow convergence of PSF reconstruction, PSF yielded 4.4% less SNR than non-PSF. For reconstruction parameters (iteration number and postreconstruction smoothing kernel size) optimizing observer SNR, PSF showed larger improvement for faint defects. The combination of TOF and PSF improved mean detection SNR as compared to non-TOF and non-PSF counterparts by 3.0% and 3.2%, respectively. Conclusions: For typical reconstruction protocol used in clinical practice, i.e., less than five iterations, TOF improved defect detectability. In contrast, PSF generally yielded less detectability. For large number of iterations, TOF+PSF yields the best observer performance.

  4. An isothermal amplification reactor with an integrated isolation membrane for point-of-care detection of infectious diseases

    PubMed Central

    Liu, Changchun; Geva, Eran; Mauk, Michael; Qiu, Xianbo; Abrams, William R.; Malamud, Daniel; Curtis, Kelly; Owen, S. Michele; Bau, Haim H.

    2015-01-01

    A simple, point of care, inexpensive, disposable cassette for the detection of nucleic acids extracted from pathogens was designed, constructed, and tested. The cassette utilizes a single reaction chamber for isothermal amplification of nucleic acids. The chamber is equipped with an integrated, flow-through, Flinders Technology Associates (Whatman FTA®) membrane for the isolation, concentration, and purification of DNA and/or RNA. The nucleic acids captured by the membrane are used directly as templates for amplification without elution, thus simplifying the cassette’s flow control. The FTA membrane also serves another critical role—enabling the removal of inhibitors that dramatically reduce detection sensitivity. Thermal control is provided with a thin film heater external to the cassette. The amplification process was monitored in real time with a portable, compact fluorescent reader. The utility of the integrated, single-chamber cassette was demonstrated by detecting the presence of HIV-1 in oral fluids. The HIV RNA was reverse transcribed and subjected to loop-mediated, isothermal amplification (LAMP). A detection limit of less than 10 HIV particles was demonstrated. The cassette is particularly suitable for resource poor regions, where funds and trained personnel are in short supply. The cassette can be readily modified to detect nucleic acids associated with other pathogens borne in saliva, urine, and other body fluids as well as in water and food. PMID:21455542

  5. Accurate Point-of-Care Detection of Ruptured Fetal Membranes: Improved Diagnostic Performance Characteristics with a Monoclonal/Polyclonal Immunoassay

    PubMed Central

    Rogers, Linda C.; Scott, Laurie; Block, Jon E.

    2016-01-01

    OBJECTIVE Accurate and timely diagnosis of rupture of membranes (ROM) is imperative to allow for gestational age-specific interventions. This study compared the diagnostic performance characteristics between two methods used for the detection of ROM as measured in the same patient. METHODS Vaginal secretions were evaluated using the conventional fern test as well as a point-of-care monoclonal/polyclonal immunoassay test (ROM Plus®) in 75 pregnant patients who presented to labor and delivery with complaints of leaking amniotic fluid. Both tests were compared to analytical confirmation of ROM using three external laboratory tests. Diagnostic performance characteristics were calculated including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. RESULTS Diagnostic performance characteristics uniformly favored ROM detection using the immunoassay test compared to the fern test: sensitivity (100% vs. 77.8%), specificity (94.8% vs. 79.3%), PPV (75% vs. 36.8%), NPV (100% vs. 95.8%), and accuracy (95.5% vs. 79.1%). CONCLUSIONS The point-of-care immunoassay test provides improved diagnostic accuracy for the detection of ROM compared to fern testing. It has the potential of improving patient management decisions, thereby minimizing serious complications and perinatal morbidity. PMID:27199579

  6. Microbead-based ligase detection reaction assay using a molecular beacon probe for the detection of low-abundance point mutations.

    PubMed

    Watanabe, Sho; Hagihara, Kenta; Tsukagoshi, Kazuhiko; Hashimoto, Masahiko

    2014-01-01

    A microbead-based ligase detection reaction (LDR) assay using a molecular beacon probe was developed for the facile and rapid detection of point mutations present in low copy numbers in a mixed population of wild-type DNA. Biotin-tagged ligation products generated in the LDR were captured on the surface of streptavidin-modified magnetic beads for purification and concentration. The resulting product-tethered microbeads were combined with a molecular beacon probe solution, and the suspension was directly flowed into a capillary. The microbeads were accumulated in a confined space within the capillary using a bar magnet. The packed bead sample was then scanned by a fluorescence scanning imager to detect the presence of any mutations. With the developed methodology, we were able to successfully detect one cancer mutation in a mixture of 400 wild-type templates (t test at 95% confidence level). Furthermore, the post-LDR processing, typically the most laborious and time-consuming step in LDR-based mutation detection assays, could be carried out much more rapidly (approximately 20 min). This was enabled by the simple bead and fluid manipulations involved in the present assay.

  7. [Comparative Study on the Three Algorithms of T-wave End Detection: Wavelet Method, Cumulative Points Area Method and Trapezium Area Method].

    PubMed

    Li, Chengtao; Zhang, Yongliang; He, Zijun; Ye, Jun; Hu, Fusong; Ma, Zuchang; Wang, Jingzhi

    2015-12-01

    In order to find the most suitable algorithm of T-wave end point detection for clinical detection, we tested three methods, which are not just dependent on the threshold value of T-wave end point detection, i. e. wavelet method, cumulative point area method and trapezium area method, in PhysioNet QT database (20 records with 3 569 beats each). We analyzed and compared their detection performance. First, we used the wavelet method to locate the QRS complex and T-wave. Then we divided the T-wave into four morphologies, and we used the three algorithms mentioned above to detect T-wave end point. Finally, we proposed an adaptive selection T-wave end point detection algorithm based on T-wave morphology and tested it with experiments. The results showed that this adaptive selection method had better detection performance than that of the single T-wave end point detection algorithm. The sensitivity, positive predictive value and the average time errors were 98.93%, 99.11% and (--2.33 ± 19.70) ms, respectively. Consequently, it can be concluded that the adaptive selection algorithm based on T-wave morphology improves the efficiency of T-wave end point detection. PMID:27079084

  8. A Colorimetric Enzyme-Linked Immunosorbent Assay (ELISA) Detection Platform for a Point-of-Care Dengue Detection System on a Lab-on-Compact-Disc.

    PubMed

    Thiha, Aung; Ibrahim, Fatimah

    2015-01-01

    The enzyme-linked Immunosorbent Assay (ELISA) is the gold standard clinical diagnostic tool for the detection and quantification of protein biomarkers. However, conventional ELISA tests have drawbacks in their requirement of time, expensive equipment and expertise for operation. Hence, for the purpose of rapid, high throughput screening and point-of-care diagnosis, researchers are miniaturizing sandwich ELISA procedures on Lab-on-a-Chip and Lab-on-Compact Disc (LOCD) platforms. This paper presents a novel integrated device to detect and interpret the ELISA test results on a LOCD platform. The system applies absorption spectrophotometry to measure the absorbance (optical density) of the sample using a monochromatic light source and optical sensor. The device performs automated analysis of the results and presents absorbance values and diagnostic test results via a graphical display or via Bluetooth to a smartphone platform which also acts as controller of the device. The efficacy of the device was evaluated by performing dengue antibody IgG ELISA on 64 hospitalized patients suspected of dengue. The results demonstrate high accuracy of the device, with 95% sensitivity and 100% specificity in detection when compared with gold standard commercial ELISA microplate readers. This sensor platform represents a significant step towards establishing ELISA as a rapid, inexpensive and automatic testing method for the purpose of point-of-care-testing (POCT) in resource-limited settings.

  9. A Colorimetric Enzyme-Linked Immunosorbent Assay (ELISA) Detection Platform for a Point-of-Care Dengue Detection System on a Lab-on-Compact-Disc

    PubMed Central

    Thiha, Aung; Ibrahim, Fatimah

    2015-01-01

    The enzyme-linked Immunosorbent Assay (ELISA) is the gold standard clinical diagnostic tool for the detection and quantification of protein biomarkers. However, conventional ELISA tests have drawbacks in their requirement of time, expensive equipment and expertise for operation. Hence, for the purpose of rapid, high throughput screening and point-of-care diagnosis, researchers are miniaturizing sandwich ELISA procedures on Lab-on-a-Chip and Lab-on-Compact Disc (LOCD) platforms. This paper presents a novel integrated device to detect and interpret the ELISA test results on a LOCD platform. The system applies absorption spectrophotometry to measure the absorbance (optical density) of the sample using a monochromatic light source and optical sensor. The device performs automated analysis of the results and presents absorbance values and diagnostic test results via a graphical display or via Bluetooth to a smartphone platform which also acts as controller of the device. The efficacy of the device was evaluated by performing dengue antibody IgG ELISA on 64 hospitalized patients suspected of dengue. The results demonstrate high accuracy of the device, with 95% sensitivity and 100% specificity in detection when compared with gold standard commercial ELISA microplate readers. This sensor platform represents a significant step towards establishing ELISA as a rapid, inexpensive and automatic testing method for the purpose of point-of-care-testing (POCT) in resource-limited settings. PMID:25993517

  10. Development of common conversion point stacking of receiver functions for detecting subducted slabs

    NASA Astrophysics Data System (ADS)

    Abe, Y.; Ohkura, T.; Hirahara, K.; Shibutani, T.

    2010-12-01

    In subduction zones, the subducting slabs are thought to convey fluid into the mantle wedge to cause arc volcanism (Hasegawa et al., 2008. Iwamori, 2007). Kawakatsu & Watada (2007) examined the Pacific slab subducting beneath northeast Japan with receiver function (RF) analysis, and revealed where the hydrated oceanic crust and the serpentinized mantle wedge exist. In the other subduction zones, it is also essential to examine subducting slabs for better understanding of water transportation and volcanic activities. In this study, we develop a new method to migrate RFs in order to examine subducting slabs with high dip angle (Abe et al., submitted to GJI) and apply this method to examination of the Philippine Sea slab (PHS). The RF technique is one of the useful methods to obtain seismic velocity discontinuities. Ps phases converted at discontinuities in a teleseismic coda can be detected by RF analysis. RFs are usually converted to depth domain assuming a 1-d velocity structure, and the geometry of discontinuities is obtained (e.g. Yamauchi et al., 2003). In subduction zones, however, subducting slabs usually dip, and we should take into account the refraction of seismic waves at dipping interfaces. Therefore, we use the multi-stage fast marching method (FMM, de Kool et al., 2006) to convert RFs into depth domain. We stack transverse RFs, since polarity of them does not change depending on their dip angles and they are better at detecting phases converted at dipping interfaces than radial RFs. We have confirmed that this method works properly with synthetic test. We apply our method to waveform data observed in Kyushu, Japan, where PHS is subducting toward WNW and the Wadati-Benioff zone dips at 30° at depths up to 80 km, and dips at 70° at depths between 80 km and 170 km. We obtain a vertical section, on which RF amplitude is projected, across central part of Kyushu perpendicular to the depth contour of the Wadati-Benioff zone. On the section, positive peaks of

  11. Detection of particulate air pollution plumes from major point sources using ERTS-1 imagery

    NASA Technical Reports Server (NTRS)

    Lyons, W. A.; Pease, S. R.

    1973-01-01

    The Earth Resources Technology Satellite (ERTS-1) launched by NASA in July 1972 has been providing thousands of high resolution multispectral images of interest to geographers, cartographers, hydrologists, and agroculturists. It has been found possible to detect the long-range (over 50 km) transport of suspected particulate plumes from the Chicago-Gary steel mill complex over Lake Michigan. The observed plumes are readily related to known steel mills, a cement plant, refineries, and fossil-fuel power plants. This has important ramifications when discussing the interregional transport of atmospheric pollutants. Analysis reveals that the Multispectral Scanner Band 5 (0.6 to 0.7 micrometer) provides the best overall contrast between the smoke and the underlying water surface.

  12. Analysis of In-Situ Vibration Monitoring for End-Point Detection of CMP Planarization Processes

    SciTech Connect

    Hetherington, Dale L.; Lauffer, James P.; Shingledecker, David M.; Stein, David J.; Wyckoff, Edward E.

    1999-05-14

    This paper details the analysis of vibration monitoring for end-point control in oxide CMP processes. Two piezoelectric accelerometers were integrated onto the backside of a stainless steel polishing head of an IPEC 472 polisher. One sensor was placed perpendicular to the carrier plate (vertical) and the other parallel to the plate (horizontal). Wafers patterned with metal and coated with oxide material were polished at different speeds and pressures. Our results show that it is possible to sense a change in the vibration signal over time during planarization of oxide material on patterned wafers. The horizontal accelerometer showed more sensitivity to change in vibration amplitude compared to the vertical accelerometer for a given polish condition. At low carrier and platen rotation rates, the change in vibration signal over time at fixed frequencies decreased approximately ½ - 1 order of magnitude (over the 2 to 10 psi polish pressure ranges). At high rotation speeds, the vibration signal remained essentially constant indicating that other factors dominated the vibration signaL These results show that while it is possible to sense changes in acceleration during polishing, more robust hardware and signal processing algorithms are required to ensure its use over a wide range of process conditions.

  13. Fully automatic hybrid registration method based on point feature detection without user intervention

    NASA Astrophysics Data System (ADS)

    Koo, Bang-Bon; Lee, Jong-Min; Kim, June-Sic; Kim, In-Young; Kwon, Jun-Soo; Kim, Sun I.

    2006-03-01

    In earlier work (KIM, J.S, MBEC, 2003), we demonstrated the registration method with a non-linear transformation using intensity similarity and feature similarity. Although the former approach showed good match in global shape of brain and feature-defined region, method contains user interventions for defining appropriate and sufficient number features. While manual delineating the region of interests for sufficient number of feature is a very time-consuming and can provide intra-, inter-rater variability, we proposed fully automatic hybrid registration via automatic feature defining method. Automatic feature definition was performed on the cortical surface from CLASP (KIM, J.S, Neuroimage, 2005) with using cortical surface matching algorithm (Robbins, S., MIA, 2004) and then applied to hybrid registration. The object of this work is to develop fully automated hybrid registration method which reveals enhanced performance in comparison to previous automated registration methods. In the result, our proposed scheme showed efficient performance from maintaining the strong points of hybrid registration without any user intervention.

  14. The usefulness of telemedicine for the detection of infection/inflammation at the point of care.

    PubMed

    Rotstein, R; Berliner, S; Fusman, R; Shapira, I; Avitzour, D; Arber, N; Zeltser, D

    2001-01-01

    The objective of this study is to examine the possibility of using Telemedicine to diagnose the presence of the inflammatory response and to assess its intensity at the point of care. One drop of citrated peripheral venous blood from 15 patients with infection/inflammation and 15 controls were used to prepare the slides. Unstained pictures were analyzed using a microscope, video camera and image analyzer (INFLAMETTM, Biovision, Tel Aviv, Israel). The jpg-compressed images were transferred via telephone to a physician in a remote location. A significant correlation was noted between the white blood cell count and the number of leukocytes per square mm by image analysis (r = 0.67 p < 0.0001 n = 30), between the degree of leukocyte adhesiveness/aggregation and the concentration of C-reactive protein (r = 0.42 p = 0.02 n = 29) and between the degree of erythrocyte aggregation and either fibrinogen concentrations (r = 0.73 p < 0.0001) or erythrocyte sedimentation (r = 0.83, p < 0.0001). No problems occurred during file transmission and there were no transfer errors. Physicians can successfully estimate the presence of an inflammatory response and its intensity using a simple slide test, image analysis, and Telemedicine technology.

  15. Detection of flow separation and stagnation points using artificial hair sensors

    NASA Astrophysics Data System (ADS)

    Phillips, D. M.; Ray, C. W.; Hagen, B. J.; Su, W.; Baur, J. W.; Reich, G. W.

    2015-11-01

    Recent interest in fly-by-feel approaches for aircraft control has motivated the development of novel sensors for use in aerial systems. Artificial hair sensors (AHSs) are one type of device that promise to fill a unique niche in the sensory suite for aerial systems. In this work, we investigate the capability of an AHS based on structural glass fibers to directly identify flow stagnation and separation points on a cylindrical domain in a steady flow. The glass fibers are functionalized with a radially aligned carbon nanotube (CNT) forest and elicit a piezoresistive response as the CNT forest impinges on electrodes in a micropore when the hair is deflected due to viscous drag forces. Particle image velocimetry is used to measure the flow field allowing for the resulting moment and force acting on the hair to be correlated with the electrical response. It is demonstrated that the AHS provides estimates for the locations of both the stagnation and separation in steady flow. From this, a simulation of a heading estimation is presented to demonstrate a potential application for hair sensors. These results motivate the construction of large arrays of hair sensors for imaging and resolving flow structures in real time.

  16. Retrospective Review of Ocular Point-of-Care Ultrasound for Detection of Retinal Detachment

    PubMed Central

    Jacobsen, Bradley; Lahham, Sari; Lahham, Shadi; Patel, Amy; Spann, Sophia; Fox, John C.

    2016-01-01

    Introduction Retinal detachment is an ocular emergency that commonly presents to the emergency department (ED). Ophthalmologists are able to accurately make this diagnosis with a dilated fundoscopic exam, scleral depression or ophthalmic ultrasound when a view to the retina is obstructed. Emergency physicians (EPs) are not trained to examine the peripheral retina, and thus ophthalmic ultrasound can be used to aid in diagnosis. We assessed the accuracy of ocular point-of-care ultrasound (POCUS) in diagnosing retinal detachment. Methods We retrospectively reviewed charts of ED patients with suspected retinal detachment who underwent ocular POCUS between July 2012 and May 2015. Charts were reviewed for patients presenting to the ED with ocular complaints and clinical concern for retinal detachment. We compared ocular POCUS performed by EPs against the criterion reference of the consulting ophthalmologist’s diagnosis. Results We enrolled a total of 109 patients. Of the 34 patients diagnosed with retinal detachment by the ophthalmologists, 31 were correctly identified as having retinal detachment by the EP using ocular POCUS. Of the 75 patients who did not have retinal detachment, 72 were ruled out by ocular POCUS by the EP. This resulted in a POCUS sensitivity of 91% (95% CI [76–98]) and specificity of 96% (95% CI [89–99]). Conclusion This retrospective study suggests that ocular POCUS performed by EPs can aid in the diagnosis of retinal detachment in ED. PMID:26973752

  17. Investigation of Point Doppler Velocimetry (PDV) for Transition Detection in Boundary Layers

    NASA Technical Reports Server (NTRS)

    Kuhlman, John M.

    1999-01-01

    A two component Point Doppler Velocimetry (PDV) system has been developed and tested. Improvements were made to an earlier PDV system, in terms of experimental techniques, as well as the data acquisition and reduction software. Measurements of the streamwise and spanwise mean and fluctuating velocities for flows from a rectangular channel and over an NACA 0012 airfoil were made, and the data were compared against hot wire data. The closest to the airfoil surface that PDV measurements could be made was on the order of 0.005 m(0.2", z/c = 0.0169). When the PDV and hot wire data were compared, the time traces for each appeared similar. The mean velocities agreed to within plus or minus 2 m/sec, while the RMS velocities agreed to plus or minus 0.4 m/sec. While the PDV time autocorrelations agreed with those of the hot wire data, the PDV power spectral densities were noisier above 750 Hz. A major source of error in these experiments was determined to be the drifting of the iodine cell stem temperatures. While the stem temperatures were controlled to within plus or minus 0.1 C, this could lead to a frequency shift of as much as 6 MHz, which translates into an error of 1.6 m/sec for the back scatter channel, and up to 6.9 m/sec for the forward scatter channel. These error estimates are consistent with the observed error magnitudes.

  18. Investigation of Point Doppler Velocimetry (PDV) for Transition Detection in Boundary Layers

    NASA Technical Reports Server (NTRS)

    Kuhlman, John; Meyers, James F. (Technical Monitor); McMichael, J. M. (Technical Monitor); Glauser, M. (Technical Monitor); Beutner, T. (Technical Monitor)

    1999-01-01

    A two-component Point Doppler Velocimeter (PDV) system has been improved through the use of vapor-limited iodine cells that have responses that are insensitive to temperature variations. Two-component PDV velocity measurements have been obtained for a 1 inch diameter uniform circular jet flow at a nominal exit velocity of 60 m/sec, corresponding to a Reynolds number of 100,000. Similar data have also been obtained for an annular jet and a swirling jet, These PDV data runs have been duplicated to judge the repeatability of these measurements, and also have been compared with hot wire anemometer data for the same flow conditions. PDV mean velocity results are repeatable to within approximately 1-2 meters per second; the PDV RMS velocity results are also quite repeatable. Exit profiles of PDV mean axial velocity data generally agree with hot wire anemometer results to within about 2 meters per second as well. However, the PDV RMS velocity results are consistently lower than the hot wire results everywhere but at the exit of the standard jet, where they are too high relative to the hot wire data. This is believed to at least be partially due to the method used to compute the RMS (Root Mean Square).

  19. Rapid and sensitive detection of Feline immunodeficiency virus using an insulated isothermal PCR-based assay with a point-of-need PCR detection platform.

    PubMed

    Wilkes, Rebecca Penrose; Kania, Stephen A; Tsai, Yun-Long; Lee, Pei-Yu Alison; Chang, Hsiu-Hui; Ma, Li-Juan; Chang, Hsiao-Fen Grace; Wang, Hwa-Tang Thomas

    2015-07-01

    Feline immunodeficiency virus (FIV) is an important infectious agent of cats. Clinical syndromes resulting from FIV infection include immunodeficiency, opportunistic infections, and neoplasia. In our study, a 5' long terminal repeat/gag region-based reverse transcription insulated isothermal polymerase chain reaction (RT-iiPCR) was developed to amplify all known FIV strains to facilitate point-of-need FIV diagnosis. The RT-iiPCR method was applied in a point-of-need PCR detection platform--a field-deployable device capable of generating automatically interpreted RT-iiPCR results from nucleic acids within 1 hr. Limit of detection 95% of FIV RT-iiPCR was calculated to be 95 copies standard in vitro transcription RNA per reaction. Endpoint dilution studies with serial dilutions of an ATCC FIV type strain showed that the sensitivity of lyophilized FIV RT-iiPCR reagent was comparable to that of a reference nested PCR. The established reaction did not amplify any nontargeted feline pathogens, including Felid herpesvirus 1, feline coronavirus, Feline calicivirus, Feline leukemia virus, Mycoplasma haemofelis, and Chlamydophila felis. Based on analysis of 76 clinical samples (including blood and bone marrow) with the FIV RT-iiPCR, test sensitivity was 97.78% (44/45), specificity was 100.00% (31/31), and agreement was 98.65% (75/76), determined against a reference nested-PCR assay. A kappa value of 0.97 indicated excellent correlation between these 2 methods. The lyophilized FIV RT-iiPCR reagent, deployed on a user-friendly portable device, has potential utility for rapid and easy point-of-need detection of FIV in cats. PMID:26185125

  20. A new method of time difference measurement: The time difference method by dual phase coincidence points detection

    NASA Technical Reports Server (NTRS)

    Zhou, Wei

    1993-01-01

    In the high accurate measurement of periodic signals, the greatest common factor frequency and its characteristics have special functions. A method of time difference measurement - the time difference method by dual 'phase coincidence points' detection is described. This method utilizes the characteristics of the greatest common factor frequency to measure time or phase difference between periodic signals. It can suit a very wide frequency range. Measurement precision and potential accuracy of several picoseconds were demonstrated with this new method. The instrument based on this method is very simple, and the demand for the common oscillator is low. This method and instrument can be used widely.

  1. Method to detect the end-point for PCR DNA amplification using an ionically labeled probe and measuring impedance change

    DOEpatents

    Miles, Robin R.; Belgrader, Phillip; Fuller, Christopher D.

    2007-01-02

    Impedance measurements are used to detect the end-point for PCR DNA amplification. A pair of spaced electrodes are located on a surface of a microfluidic channel and an AC or DC voltage is applied across the electrodes to produce an electric field. An ionically labeled probe will attach to a complementary DNA segment, and a polymerase enzyme will release the ionic label. This causes the conductivity of the solution in the area of the electrode to change. This change in conductivity is measured as a change in the impedance been the two electrodes.

  2. Detection of the end point temperature of thermal denatured protein in fish and chicken meat through SDS-PAGE electrophoresis

    NASA Astrophysics Data System (ADS)

    Gao, Hongwei; Mao, Mao; Liang, Chengzhu; Lin, Chao; Xiang, Jianhai

    2009-03-01

    Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was applied in the detection of the end point temperature (EPT) of thermal denatured protein in fish and meat in this study. It was also used in studying the thermal denatured temperature range of proteins in salmon and chicken meat. The results show that the temperature ranges of denatured proteins were from 65°C to 75°C, and these temperature ranges were influenced by the processing methods. Through SDS-PAGE, the features of repeated heating thermal denatured proteins under the same temperature and processing time were studied. The electrophoresis patterns of thermal denatured proteins determined through repeated heating at the same temperature did not exhibit any change. For the detection of cooked fish and meat samples, they were subjected to applying the SDS-PAGE method, which revealed an EPT ranging from 60°C to 80°C.

  3. Voltammetric iodometric titration of ascorbic acid with dead-stop end-point detection in fresh vegetables and fruit samples.

    PubMed

    Verdini, R A; Lagier, C M

    2000-07-01

    The present work describes a method for determining ascorbic acid, which combines iodometry with a voltammetric technique to detect the end point of the titration. In addition, the validity of the method applied to natural vegetable or fruit samples was assessed. The results were compared with those obtained by an accurate method such as HPLC using UV detection. Similar values of ascorbic acid for different natural samples were obtained by means of this approach (p > 0.05). The limit of quantification was 0.1 mg. This technique presents the advantage of other electroanalytical methods such as avoiding filtration or ultracentrifugation steps, with the additional benefit of using the platinum electrodes, which are routinely used in the laboratory. These facts allow a rapid and efficient quantification of ascorbic acid with very low cost of reagents and equipment.

  4. Clinical impact of time-of-flight and point response modeling in PET reconstructions: a lesion detection study

    NASA Astrophysics Data System (ADS)

    Schaefferkoetter, Joshua; Casey, Michael; Townsend, David; El Fakhri, Georges

    2013-03-01

    Time-of-flight (TOF) and point spread function (PSF) modeling have been shown to improve PET reconstructions, but the impact on physicians in the clinical setting has not been thoroughly investigated. A lesion detection and localization study was performed using simulated lesions in real patient images. Four reconstruction schemes were considered: ordinary Poisson OSEM (OP) alone and combined with TOF, PSF, and TOF + PSF. The images were presented to physicians experienced in reading PET images, and the performance of each was quantified using localization receiver operating characteristic. Numerical observers (non-prewhitening and Hotelling) were used to identify optimal reconstruction parameters, and observer SNR was compared to the performance of the physicians. The numerical models showed good agreement with human performance, and best performance was achieved by both when using TOF + PSF. These findings suggest a large potential benefit of TOF + PSF for oncology PET studies, especially in the detection of small, low-intensity, focal disease in larger patients.

  5. Nano-engineered flexible pH sensor for point-of-care urease detection

    NASA Astrophysics Data System (ADS)

    Sardarinejad, A.; Maurya, D. K.; Tay, C. Y.; Marshall, B. J.; Alameh, K.

    2015-12-01

    Accurate pH monitoring is crucial for many applications, such as, water quality monitoring, blood monitoring, chemical and biological analyses, environmental monitoring and clinical diagnostic. The most common technique for pH measurement is based on the use of conventional glass pH electrodes. Glass electrodes have several limitations, such as mechanical fragility, large size, limited shapes and high cost, making them impractical for implementation as Lab-onchips and pH sensor capsules. Various metal oxides, such as RuO2, IrO2, TiO2, SnO2, Ta2O5 and PdO have recently been proposed for the realization of pH sensing electrodes. Specifically, ruthenium oxide exhibits unique properties including thermal stability, excellent corrosion resistance, low hysteresis high sensitivity, and low resistivity. In this paper, we demonstrate the concept of a miniaturized ion selective electrode (ISE) based pH sensor for point-of-care urease monitoring. The sensor comprises a thin film RuO2 on platinum sensing electrode, deposited using E-beam and R.F. magnetron sputtering, in conjunction with an integrated Ag/AgCl reference electrode. The performance and characterization of the developed pH/urea sensors in terms of sensitivity, resolution, reversibility and hysteresis are investigated. Experimental results show a linear potential-versus-urea-concentration response for urea concentrations in the range 0 - 180 mg/ml. Experimental results demonstrate super-Nernstian slopes in the range of 64.33 mV/pH - 73.83 mV/pH for RF sputtered RuO2 on platinum sensing electrode using a 80%:20% Ar:O2 gas ratio. The RuO2 sensor exhibits stable operation and fast dynamic response, making it attractive for in vivo use, wearable and flexible biomedical sensing applications.

  6. Replica Analysis of Multiuser Detection for Code Division Multiple Access with M-Ary Phase-Shift Keying

    NASA Astrophysics Data System (ADS)

    Kato, Hiroyuki; Okada, Masato; Miyoshi, Seiji

    2013-07-01

    We analyze the performance of the maximizer of the posterior marginals (MPM) detector for code division multiple access (CDMA) multiuser detection with M-ary phase shift keying (M-ary PSK) in the large system limit by the replica method. The obtained theory agrees with computer simulation reasonably well. We also derive the theory in the case of the large M limit and discuss the dependence of the properties of M-ary PSK CDMA communication on M. We show that the waterfall phenomenon occurs for both the finite and infinite values of M. We also show that a value of M for which the decoded phase information on the original user symbol becomes minimum exists. Furthermore, we discuss the relationship between the theory based on the replica method and that based on self-consistent signal-to-noise analysis (SCSNA).

  7. Detection of the Deformation of an Intelligent Textile in a Specific Point

    PubMed Central

    Alsina, Maria; Escudero, Francesc; Margalef, Jordi; Cambra, Vicente; Gisbert, José

    2007-01-01

    An intelligent textile is a textile structure that measures and reacts in front of external agents or stimulus with or without integrated electronic equipment. The finality of the present textile is to take one more step towards intelligent textile, considering the integration of electronics and textile needs, to be industrially viable and to keep up the necessary competitiveness, raising the final price as little as possible. The finality of these experiments is to develop a textile that varies in conductivity and resistance in relation to the elongation of the textile, detecting changes caused by the alteration of a piece of clothing, from the pressure of a finger on the material, for example. One of the most important characteristics of textile is the capacity of reproducing measures, of varying the response in different tests. Two lines of research were opened: the study of the most adequate structure to achieve a response that can be reproduced and the study of the best way of taking measures without altering the behavior of the textile.

  8. Evaluation of alkali metal sulfate dew point measurement for detection of hot corrosion conditions in PFBC flue gas

    SciTech Connect

    Helt, J.E.

    1980-11-01

    Hot corrosion in combustion systems is, in general, the accelerated oxidation of nickel, cobalt, and iron-base alloys which occurs in the presence of small amounts of impurities - notably, sodium, sulfur, chlorine, and vanadium. There is no real consensus on which mechanisms are primarily responsible for high-temperature corrosion. One point generally accepted, however, is that corrosion reactions take place at an appreciable rate only in the presence of a liquid phase. When coal is the fuel for combustion, hot corrosion may occur in the form of accelerated sulfidation. It is generally agreed by investigators that molten alkali metal sulfates (Na/sub 2/SO/sub 4/ and K/sub 2/SO/sub 4/) are the principal agents responsible for the occurrence of sulfidation. Although molten sodium sulfate by itself appears to have little or no effect on the corrosion of metal alloys, its presence may increase the accessibility of the bare metal surface to the external atmosphere. If this atmosphere contains either a reductant and/or an oxide such as SiO/sub 2/, SO/sub 3/, or NaOH(Na/sub 2/O), corrosion is likely to occur. Alkali metal sulfate dew point measurement was evaluated as a means of anticipating hot corrosion in the gas turbine of a pressurized fluidized-bed combustion system. The hot corrosion mechanism and deposition rate theory were reviewed. Two methods of dew point measurement, electrical conductivity and remote optical techniques, were identified as having a potential for this application. Both techniques are outlined; practical measurement systems are suggested; and potential problem areas are identified.

  9. Point of care nucleic acid detection of viable pathogenic bacteria with isothermal RNA amplification based paper biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Hongxing; Xing, Da; Zhou, Xiaoming

    2014-09-01

    Food-borne pathogens such as Listeria monocytogenes have been recognized as a major cause of human infections worldwide, leading to substantial health problems. Food-borne pathogen identification needs to be simpler, cheaper and more reliable than the current traditional methods. Here, we have constructed a low-cost paper biosensor for the detection of viable pathogenic bacteria with the naked eye. In this study, an effective isothermal amplification method was used to amplify the hlyA mRNA gene, a specific RNA marker in Listeria monocytogenes. The amplification products were applied to the paper biosensor to perform a visual test, in which endpoint detection was performed using sandwich hybridization assays. When the RNA products migrated along the paper biosensor by capillary action, the gold nanoparticles accumulated at the designated Test line and Control line. Under optimized experimental conditions, as little as 0.5 pg/μL genomic RNA from Listeria monocytogenes could be detected. The whole assay process, including RNA extraction, amplification, and visualization, can be completed within several hours. The developed method is suitable for point-of-care applications to detect food-borne pathogens, as it can effectively overcome the false-positive results caused by amplifying nonviable Listeria monocytogenes.

  10. Amplification-free point of care immunosensor for detecting type V collagen at a concentration level of ng/ml

    NASA Astrophysics Data System (ADS)

    Chung, Pei-Yu; Bracho-Sanchez, Evelyn R.; Jiang, Peng; Seagrave, JeanClare; Duncan, Matthew R.; Grotendorst, Gary R.; Schultz, Gregory; Batich, Christopher

    2011-06-01

    Point-of-care testing (POCT) is applicable in the immediate vicinity of the patient, where timely diagnosis or prognostic information could help doctors decide the following treatment. Among types of developed POCT, gold nanoparticle based lateral flow strip technology provides advantages such as simple operation, cost-effectiveness, and a user-friendly platform. Therefore, this type of POCT is most likely to be used in battlefields and developing countries. However, conventional lateral flow strips suffer from low detection limits. Although enzyme-linked amplification was demonstrated to improve the detection limit and sensitivity by stronger visible lines or by permitting electrochemical analytical instrumentation, the enzyme labels have potential to cause interference with other enzymes in our body fluids. To eliminate this limitation, we developed an amplification-free gold nanoparticle-based immunosensor applied for detecting collagen type V, which is produced or released abnormally during rejection of lung transplants and sulfur mustard exposure. By using suitable blocking protein to stabilize gold nanoparticles as the reporter probe, a low detection limit of ng/ml was achieved. This strategy is a promising platform for clinical POCT, with potential applications in military or disaster response.

  11. Comparison of Rapid Point-of-Care Tests for Detection of Antibodies to Hepatitis C Virus.

    PubMed

    Fisher, Dennis G; Hess, Kristen L; Erlyana, Erlyana; Reynolds, Grace L; Cummins, Catherine A; Alonzo, Todd A

    2015-09-01

    Background.  Hepatitis C is one of the most prevalent blood-borne diseases in the United States. Despite the benefits of early screening, among 3.2 million Americans who are infected with hepatitis C virus (HCV), 50%-70% are unaware of their infection status. Methods.  Data were collected between 2011 and 2014, from 1048 clients who were in the following groups: (1) injection drug users, (2) women at sexual risk, (3) gay and bisexual men, and (4) transgender individuals. The sensitivity and specificity of point-of-care tests included (1) the MedMira rapid human immunodeficiency virus (HIV)/HCV antibody test, (2) MedMira hepatitis B (HBV)/HIV/HCV antibody test, (3) Chembio HCV Screen Assay used with both whole blood and (4) oral specimens, (5) Chembio HIV-HCV Assay also used with both whole blood and (6) oral specimens, (7) Chembio HIV-HCV-Syphilis Assay, and (8) OraSure HCV Rapid Antibody Test used with whole blood. The gold standard for the HCV tests were HCV enzyme immunoassay (EIA) 2.0. Results.  OraSure had the highest sensitivity at 92.7% (95% confidence interval [CI] = 88.8%-96.5%) followed closely by Chembio's 3 blood tests at 92.1% (95% CI = 87.7%-96.4%), 91.5% (95% CI = 87.2%-95.7%), and 92.3% (95% CI = 88.4%-96.2%). The sensitivities of MedMira HIV/HCV and MedMira HIV/HCV/HBV tests were the lowest, at 79.1% (95% CI = 72.6%-85.5%), and 81.5% (95% CI = 75.2%-87.8%), respectively. Specificity for the OraSure was 99.8% (95% CI = 99.4%-100%); specificity for the Chembio blood tests was 99.2% (95% CI = 98.6%-99.9%), 99.4% (95% CI = 98.8%-99.9%), and 99.3% (95% CI = 98.8%-99.9%); and specificity for the MedMira was100% and 100%. False-negative results were associated with HIV and hepatitis B core antibody serostatus. Conclusions.  The OraSure and Chembio blood tests (including those multiplexed with HIV and syphilis) appear to good performance characteristics. This study has identified potential limitations of rapid testing in those testing positive for

  12. Robust control chart for change point detection of process variance in the presence of disturbances

    NASA Astrophysics Data System (ADS)

    Huat, Ng Kooi; Midi, Habshah

    2015-02-01

    A conventional control chart for detecting shifts in variance of a process is typically developed where in most circumstances the nominal value of variance is unknown and based upon one of the essential assumptions that the underlying distribution of the quality characteristic is normal. However, this is not always the case as it is fairly evident that the statistical estimates used for these charts are very sensitive to the occurrence of occasional outliers. This is for the reason that the robust control charts are put forward when the underlying normality assumption is not met, and served as a remedial measure to the problem of contamination in process data. Realizing that the existing approach, namely Biweight A pooled residuals method, appears to be resistance to localized disturbances but lack of efficiency when there are diffuse disturbances. To be concrete, diffuse disturbances are those that have equal change of being perturbed by any observation, while a localized disturbance will have effect on every member of a certain subsample or subsamples. Since the efficiency of estimators in the presence of disturbances can rely heavily upon whether the disturbances are distributed throughout the observations or concentrated in a few subsamples. Hence, to this end, in this paper we proposed a new robust MBAS control chart by means of subsample-based robust Modified Biweight A scale estimator in estimating the process standard deviation. It has strong resistance to both localized and diffuse disturbances as well as high efficiency when no disturbances are present. The performance of the proposed robust chart was evaluated based on some decision criteria through Monte Carlo simulation study.

  13. White-light interferometers with polarizing optics for length measurements with an applicable zero-point detection

    NASA Astrophysics Data System (ADS)

    Ullmann, V.; Emam, S.; Manske, E.

    2015-08-01

    For absolute length and form measurements at a large working distance (>150 mm) two special interferometers, a tandem interferometer and a Michelson interferometer with achromatic polarizing optics are constructed. In our experiments, both consist of a combination of one low-coherence interferometer and one laser interferometer. For the low-coherence interferometer part, a simple white-light source with less than 100 µW optical power output is chosen. It bases upon a low-cost fiber-coupled near-infrared LED with a large spectral width (FWHM > 68 nm at 825 nm). The use of achromatic polarizing optics such as broadband polarizing beamsplitters and achromatic quarter-wave plates in the low-coherence interferometer parts increases the contrast level of the white-light signal fringe pattern to nearly 100%. Furthermore, the fringe pattern in a polarized interferometer has no subsignatures and is unique. Hence, different algorithms are tested for signal processing and automated zero-point detection of the white-light signature. The software for an automated measurement is tested in a standard room without thermal control and without damped oscillation. Therefore, in experiments with the tandem interferometer, it was possible to measure the zero-point position of a white-light signature with a peak-to-peak difference of 154 nm under uncontrolled environmental conditions without thermal stabilization. The white-light Michelson interferometer with polarizing achromatic optics allows zero-point detections with a standard deviation (mean value) of less than 15 nm. The drift is proved through measurement results.

  14. Rapid, point-of-care extraction of human immunodeficiency virus type 1 proviral DNA from whole blood for detection by real-time PCR.

    PubMed

    Jangam, Sujit R; Yamada, Douglas H; McFall, Sally M; Kelso, David M

    2009-08-01

    PCR detection of human immunodeficiency virus type 1 (HIV-1) proviral DNA is the method recommended for use for the diagnosis of HIV-1 infection in infants in limited-resource settings. Currently, testing must be performed in central laboratories, which are usually located some distance from health care facilities. While the collection and transportation of samples, such as dried blood spots, has improved test accessibility, the results are often not returned for several weeks. To enable PCR to be performed at the point of care while the mothers wait, we have developed a vertical filtration method that uses a separation membrane and an absorbent pad to extract cellular DNA from whole blood in less than 2 min. Cells are trapped in the separation membrane as the specimen is collected, and then a lysis buffer is added. The membrane retains the DNA, while the buffer washes away PCR inhibitors, which get wicked into the absorbent blotter pad. The membrane containing the entrapped DNA is then added to the PCR mixture without further purification. The method demonstrates a high degree of reproducibility and analytical sensitivity and allows the quantification of as few as 20 copies of HIV-1 proviral DNA from 100 microl of blood. In a blinded study with 182 longitudinal samples from infants (ages, 0 to 72 weeks) obtained from the Women and Infants Transmission Study, our assay demonstrated a sensitivity of 99% and a specificity of 100%. PMID:19644129

  15. Rapid point-of-care detection of the tuberculosis pathogen using a BlaC-specific fluorogenic probe

    NASA Astrophysics Data System (ADS)

    Xie, Hexin; Mire, Joseph; Kong, Ying; Chang, Mihee; Hassounah, Hany A.; Thornton, Chris N.; Sacchettini, James C.; Cirillo, Jeffrey D.; Rao, Jianghong

    2012-10-01

    Early diagnosis of tuberculosis can dramatically reduce both its transmission and the associated death rate. The extremely slow growth rate of the causative pathogen, Mycobacterium tuberculosis (Mtb), however, makes this challenging at the point of care, particularly in resource-limited settings. Here we report the use of BlaC (an enzyme naturally expressed/secreted by tubercle bacilli) as a marker and the design of BlaC-specific fluorogenic substrates as probes for Mtb detection. These probes showed an enhancement by 100-200 times in fluorescence emission on BlaC activation and a greater than 1,000-fold selectivity for BlaC over TEM-1 β-lactamase, an important factor in reducing false-positive diagnoses. Insight into the BlaC specificity was revealed by successful co-crystallization of the probe/enzyme mutant complex. A refined green fluorescent probe (CDG-OMe) enabled the successful detection of live pathogen in less than ten minutes, even in unprocessed human sputum. This system offers the opportunity for the rapid, accurate detection of very low numbers of Mtb for the clinical diagnosis of tuberculosis in sputum and other specimens.

  16. A volumetric meter chip for point-of-care quantitative detection of bovine catalase for food safety control.

    PubMed

    Cui, Xingye; Hu, Jie; Choi, Jane Ru; Huang, Yalin; Wang, Xuemin; Lu, Tian Jian; Xu, Feng

    2016-09-01

    A volumetric meter chip was developed for quantitative point-of-care (POC) analysis of bovine catalase, a bioindicator of bovine mastitis, in milk samples. The meter chip displays multiplexed quantitative results by presenting the distance of ink bar advancement that is detectable by the naked eye. The meter chip comprises a poly(methyl methacrylate) (PMMA) layer, a double-sided adhesive (DSA) layer and a glass slide layer fabricated by the laser-etching method, which is typically simple, rapid (∼3 min per chip), and cost effective (∼$0.2 per chip). Specially designed "U shape" reaction cells are covered by an adhesive tape that serves as an on-off switch, enabling the simple operation of the assay. As a proof of concept, we employed the developed meter chip for the quantification of bovine catalase in raw milk samples to detect catalase concentrations as low as 20 μg/mL. The meter chip has great potential to detect various target analytes for a wide range of POC applications. PMID:27543029

  17. Application of flat panel OLED display technology for the point-of-care detection of circulating cancer biomarkers

    PubMed Central

    Katchman, Benjamin A.; Smith, Joseph T.; Obahiagbon, Uwadiae; Kesiraju, Sailaja; Lee, Yong-Kyun; O’Brien, Barry; Kaftanoglu, Korhan; Blain Christen, Jennifer; Anderson, Karen S.

    2016-01-01

    Point-of-care molecular diagnostics can provide efficient and cost-effective medical care, and they have the potential to fundamentally change our approach to global health. However, most existing approaches are not scalable to include multiple biomarkers. As a solution, we have combined commercial flat panel OLED display technology with protein microarray technology to enable high-density fluorescent, programmable, multiplexed biorecognition in a compact and disposable configuration with clinical-level sensitivity. Our approach leverages advances in commercial display technology to reduce pre-functionalized biosensor substrate costs to pennies per cm2. Here, we demonstrate quantitative detection of IgG antibodies to multiple viral antigens in patient serum samples with detection limits for human IgG in the 10 pg/mL range. We also demonstrate multiplexed detection of antibodies to the HPV16 proteins E2, E6, and E7, which are circulating biomarkers for cervical as well as head and neck cancers. PMID:27374875

  18. Detecting and Analyzing Corrosion Spots on the Hull of Large Marine Vessels Using Colored 3d LIDAR Point Clouds

    NASA Astrophysics Data System (ADS)

    Aijazi, A. K.; Malaterre, L.; Tazir, M. L.; Trassoudaine, L.; Checchin, P.

    2016-06-01

    This work presents a new method that automatically detects and analyzes surface defects such as corrosion spots of different shapes and sizes, on large ship hulls. In the proposed method several scans from different positions and viewing angles around the ship are registered together to form a complete 3D point cloud. The R, G, B values associated with each scan, obtained with the help of an integrated camera are converted into HSV space to separate out the illumination invariant color component from the intensity. Using this color component, different surface defects such as corrosion spots of different shapes and sizes are automatically detected, within a selected zone, using two different methods depending upon the level of corrosion/defects. The first method relies on a histogram based distribution whereas the second on adaptive thresholds. The detected corrosion spots are then analyzed and quantified to help better plan and estimate the cost of repair and maintenance. Results are evaluated on real data using different standard evaluation metrics to demonstrate the efficacy as well as the technical strength of the proposed method.

  19. A volumetric meter chip for point-of-care quantitative detection of bovine catalase for food safety control.

    PubMed

    Cui, Xingye; Hu, Jie; Choi, Jane Ru; Huang, Yalin; Wang, Xuemin; Lu, Tian Jian; Xu, Feng

    2016-09-01

    A volumetric meter chip was developed for quantitative point-of-care (POC) analysis of bovine catalase, a bioindicator of bovine mastitis, in milk samples. The meter chip displays multiplexed quantitative results by presenting the distance of ink bar advancement that is detectable by the naked eye. The meter chip comprises a poly(methyl methacrylate) (PMMA) layer, a double-sided adhesive (DSA) layer and a glass slide layer fabricated by the laser-etching method, which is typically simple, rapid (∼3 min per chip), and cost effective (∼$0.2 per chip). Specially designed "U shape" reaction cells are covered by an adhesive tape that serves as an on-off switch, enabling the simple operation of the assay. As a proof of concept, we employed the developed meter chip for the quantification of bovine catalase in raw milk samples to detect catalase concentrations as low as 20 μg/mL. The meter chip has great potential to detect various target analytes for a wide range of POC applications.

  20. Novel MDM-PON scheme utilizing self-homodyne detection for high-speed/capacity access networks.

    PubMed

    Chen, Yuanxiang; Li, Juhao; Zhu, Paikun; Wu, Zhongying; Zhou, Peng; Tian, Yu; Ren, Fang; Yu, Jinyi; Ge, Dawei; Chen, Jingbiao; He, Yongqi; Chen, Zhangyuan

    2015-12-14

    In this paper, we propose a cost-effective, energy-saving mode-division-multiplexing passive optical network (MDM-PON) scheme utilizing self-homodyne detection for high-speed/capacity access network based on low modal-crosstalk few-mode fiber (FMF) and all-fiber mode multiplexer/demultiplexer (MUX/DEMUX). In the proposed scheme, one of the spatial modes is used to transmit a portion of signal carrier (namely pilot-tone) as the local oscillator (LO), while the others are used for signal-bearing channels. At the receiver, the pilot-tone and the signal can be separated without strong crosstalk and sent to the receiver for coherent detection. The spectral efficiency (SE) is significantly enhanced when multiple spatial channels are used. Meanwhile, the self-homodyne detection scheme can effectively suppress laser phase noise, which relaxes the requirement for the lasers line-width at the optical line terminal or optical network units (OLT/ONUs). The digital signal processing (DSP) at the receiver is also simplified since it removes the need for frequency offset compensation and complex phase correction, which reduces the computational complexity and energy consumption. Polarization division multiplexing (PDM) that offers doubled SE is also supported by the scheme. The proposed scheme is scalable to multi-wavelength application when wavelength MUX/DEMUX is utilized. Utilizing the proposed scheme, we demonstrate a proof of concept 4 × 40-Gb/s orthogonal frequency division multiplexing (OFDM) transmission over 55-km FMF using low modal-crosstalk two-mode FMF and MUX/DEMUX with error free operation. Compared with back to back case, less than 1-dB Q-factor penalty is observed after 55-km FMF of the four channels. Signal power and pilot-tone power are also optimized to achieve the optimal transmission performance. PMID:26698996

  1. Microfluidic toner-based analytical devices: disposable, lightweight, and portable platforms for point-of-care diagnostics with colorimetric detection.

    PubMed

    Oliveira, Karoliny Almeida; de Souza, Fabrício Ribeiro; de Oliveira, Cristina Rodrigues; da Silveira, Lucimeire Antonelli; Coltro, Wendell Karlos Tomazelli

    2015-01-01

    This chapter describes the development of microfluidic toner-based analytical devices (μTADs) to perform clinical diagnostics using a scanner or cell-phone camera. μTADs have been produced in a platform composed of polyester and toner by the direct-printing technology (DPT) in a matter of minutes. This technology offers simplicity and versatility, and it does not require any sophisticated instrumentation. Toner-based devices integrate the current generation of disposable analytical devices along paper-based chips. The cost of one μTAD has been estimated to be lower than $0.10. In addition, these platforms are lightweight and portable thus enabling their use for point-of-care applications. In the last 5 years, great efforts have been dedicated to spread out the use of μTADs in bioassays. The current chapter reports the fabrication of printed microplates and integrated microfluidic toner-based devices for dengue diagnostics and rapid colorimetric assays with clinically relevant analytes including cholesterol, triglycerides, total proteins, and glucose. The use of μTADs associated with cell-phone camera may contribute to the health care, in special, to people housed in developing regions or with limited access to clinics and hospitals.

  2. Microfluidic toner-based analytical devices: disposable, lightweight, and portable platforms for point-of-care diagnostics with colorimetric detection.

    PubMed

    Oliveira, Karoliny Almeida; de Souza, Fabrício Ribeiro; de Oliveira, Cristina Rodrigues; da Silveira, Lucimeire Antonelli; Coltro, Wendell Karlos Tomazelli

    2015-01-01

    This chapter describes the development of microfluidic toner-based analytical devices (μTADs) to perform clinical diagnostics using a scanner or cell-phone camera. μTADs have been produced in a platform composed of polyester and toner by the direct-printing technology (DPT) in a matter of minutes. This technology offers simplicity and versatility, and it does not require any sophisticated instrumentation. Toner-based devices integrate the current generation of disposable analytical devices along paper-based chips. The cost of one μTAD has been estimated to be lower than $0.10. In addition, these platforms are lightweight and portable thus enabling their use for point-of-care applications. In the last 5 years, great efforts have been dedicated to spread out the use of μTADs in bioassays. The current chapter reports the fabrication of printed microplates and integrated microfluidic toner-based devices for dengue diagnostics and rapid colorimetric assays with clinically relevant analytes including cholesterol, triglycerides, total proteins, and glucose. The use of μTADs associated with cell-phone camera may contribute to the health care, in special, to people housed in developing regions or with limited access to clinics and hospitals. PMID:25626533

  3. Evaluation of Optical Detection Platforms for Multiplexed Detection of Proteins and the Need for Point-of-Care Biosensors for Clinical Use

    PubMed Central

    Spindel, Samantha; Sapsford, Kim E.

    2014-01-01

    This review investigates optical sensor platforms for protein multiplexing, the ability to analyze multiple analytes simultaneously. Multiplexing is becoming increasingly important for clinical needs because disease and therapeutic response often involve the interplay between a variety of complex biological networks encompassing multiple, rather than single, proteins. Multiplexing is generally achieved through one of two routes, either through spatial separation on a surface (different wells or spots) or with the use of unique identifiers/labels (such as spectral separation—different colored dyes, or unique beads—size or color). The strengths and weaknesses of conventional platforms such as immunoassays and new platforms involving protein arrays and lab-on-a-chip technology, including commercially-available devices, are discussed. Three major public health concerns are identified whereby detecting medically-relevant markers using Point-of-Care (POC) multiplex assays could potentially allow for a more efficient diagnosis and treatment of diseases. PMID:25429414

  4. Evaluation of optical detection platforms for multiplexed detection of proteins and the need for point-of-care biosensors for clinical use.

    PubMed

    Spindel, Samantha; Sapsford, Kim E

    2014-11-25

    This review investigates optical sensor platforms for protein multiplexing, the ability to analyze multiple analytes simultaneously. Multiplexing is becoming increasingly important for clinical needs because disease and therapeutic response often involve the interplay between a variety of complex biological networks encompassing multiple, rather than single, proteins. Multiplexing is generally achieved through one of two routes, either through spatial separation on a surface (different wells or spots) or with the use of unique identifiers/labels (such as spectral separation-different colored dyes, or unique beads-size or color). The strengths and weaknesses of conventional platforms such as immunoassays and new platforms involving protein arrays and lab-on-a-chip technology, including commercially-available devices, are discussed. Three major public health concerns are identified whereby detecting medically-relevant markers using Point-of-Care (POC) multiplex assays could potentially allow for a more efficient diagnosis and treatment of diseases.

  5. A Customized Raman System for Point-of-Care Detection of Arthropathic Crystals in the Synovial Fluid

    PubMed Central

    Li, Bolan; Yang, Shan; Akkus, Ozan

    2014-01-01

    Monosodium urate (MSU) and calcium pyrophosphate dihydrate (CPPD) are the most frequently observed crystals in joint space, leading to painful arthropathies. Correct diagnosis of the crystal identity is critical for the appropriate course of treatment. In this work, a custom Raman device in combination with a practical and efficient sample preparation method is used for chemically selective diagnosis of MSU and CPPD crystals in an automated fashion. The samples were prepared by a brief enzymatic digestion treatment of synovial fluid followed by a customized filtration process which was able to congregate crystals over a submillimeter sized spot. The data acquisition and collection was automated to collect multiple spectra distributed over the filtration spot. The performance of the cost-efficient Raman system was compared to a research-grade high fidelity Raman instrument. The custom-designed Raman device could detect MSU crystals at sub-clinical concentration of 0.1 μg/mL, and 1 μg/mL for CPPD crystals. This practical sample preparation approach in tandem with the low-cost customized Raman device has a potential to be a novel tool for point-and-shoot Raman diagnosis of arthritic crystals in synovial fluid at the point of care. PMID:24419093

  6. Evaluation of Clouds and the Earth's Radiant Energy System (CERES) Scanner Pointing Accuracy using a Coastline Detection System

    NASA Technical Reports Server (NTRS)

    Currey, Chris; Smith, Lou; Neely, Bob

    1998-01-01

    Clouds and the Earth's Radiant Energy System (CERES) is a National Aeronautics and Space Administration (NASA) investigation to examine the role of clouds in the radiative energy flow through the Earth-atmosphere system. The first CERES scanning radiometer was launched on November 27, 1997 into a 35 inclination, 350 km altitude orbit, on the Tropical Rainfall Measuring Mission (TRMM) spacecraft. The CERES instrument consists of a three channel scanning broadband radiometer. The spectral bands measure shortwave (0.3 - 5 microns), window (8 - 12 microns), and total (0.3 - 100 microns) radiation reflected or emitted from the Earth-atmosphere system. Each Earth viewing measurement is geolocated to the Earth fixed coordinate system using satellite ephemeris, Earth rotation and geoid, and instrument pointing data. The interactive CERES coastline detection system is used to assess the accuracy of the CERES geolocation process. By analyzing radiative flux gradients at the boundaries of ocean and land masses, the accuracy of the scanner measurement locations may be derived for the CERES/TRMM instrument/satellite system. The resulting CERES measurement location errors are within 10% of the nadir footprint size. Precise pointing knowledge of the Visible and Infrared Scanner (VIRS) is required for convolution of cloud properties onto the CERES footprint; initial VIRS coastline results are included.

  7. Context-dependent detection of non-linearly distributed points for vegetation classification in airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Horvat, Denis; Žalik, Borut; Mongus, Domen

    2016-06-01

    This paper proposes a new method for the detection of vegetation in LiDAR data. As vegetation points are characterised by non-linear distributions, they are efficiently recognised based-on large errors obtained when applying the local fitting of planar surfaces. In addition, three contextual filters are introduced capable of dealing with those exceptions that do not conform with previous interpretations. Namely, they are designed for detecting overgrowing vegetation, small objects attached to the planar surfaces (such as balconies, chimneys, and noise within the buildings) and small objects that do not belong to vegetation (vehicles, statues, fences). During the validation, the proposed method achieved over 97% correctness as well as completeness of vegetation recognition in rural areas while its average accuracy in urban settings was 90.7% in terms of F 1 -scores. The method uses only three input parameters and allows for efficient compensation between completeness and correctness, without significantly affecting the F 1 -score. Sensitivity analysis of the method also confirmed the robustness against a sub-optimal definition of the input parameters.

  8. Use of a point-of-care beta-hydroxybutyrate sensor for detection of ketonemia in dogs

    PubMed Central

    Henderson, Debra W.; Schlesinger, Daniel P.

    2010-01-01

    The urine test strip is the most common test used to detect ketones in veterinary patients, but it can underestimate the degree of ketonuria and hence, ketonemia. Additionally, adequate urine samples for analysis may be difficult to obtain from dehydrated animals. The standard method used to detect and monitor ketonemia in human medicine is measurement of serum or whole blood beta-hydroxybutyrate (βHOB). A point-of-care (POC) analyzer has been validated for this purpose in humans. This study compared the accuracy of the POC device to an enzymatic reaction laboratory method for measurement of βHOB in dogs. Although the POC sensor tended to overestimate βHOB concentrations, there was good correlation (R2 = 0.96) and good agreement between the 2 methods with a bias +/− precision of 0.0860 +/− 0.3410 mmol/L βHOB. The POC βHOB sensor can be useful for assessing ketonemia in dogs. PMID:21119867

  9. Modeling of delamination in carbon/epoxy composite laminates under four point bending for damage detection and sensor placement optimization

    NASA Astrophysics Data System (ADS)

    Adu, Stephen Aboagye

    Laminated carbon fiber-reinforced polymer composites (CFRPs) possess very high specific strength and stiffness and this has accounted for their wide use in structural applications, most especially in the aerospace industry, where the trade-off between weight and strength is critical. Even though they possess much larger strength ratio as compared to metals like aluminum and lithium, damage in the metals mentioned is rather localized. However, CFRPs generate complex damage zones at stress concentration, with damage progression in the form of matrix cracking, delamination and fiber fracture or fiber/matrix de-bonding. This thesis is aimed at performing; stiffness degradation analysis on composite coupons, containing embedded delamination using the Four-Point Bend Test. The Lamb wave-based approach as a structural health monitoring (SHM) technique is used for damage detection in the composite coupons. Tests were carried-out on unidirectional composite coupons, obtained from panels manufactured with pre-existing defect in the form of embedded delamination in a laminate of stacking sequence [06/904/0 6]T. Composite coupons were obtained from panels, fabricated using vacuum assisted resin transfer molding (VARTM), a liquid composite molding (LCM) process. The discontinuity in the laminate structure due to the de-bonding of the middle plies caused by the insertion of a 0.3 mm thick wax, in-between the middle four (4) ninety degree (90°) plies, is detected using lamb waves generated by surface mounted piezoelectric (PZT) actuators. From the surface mounted piezoelectric sensors, response for both undamaged (coupon with no defect) and damaged (delaminated coupon) is obtained. A numerical study of the embedded crack propagation in the composite coupon under four-point and three-point bending was carried out using FEM. Model validation was then carried out comparing the numerical results with the experimental. Here, surface-to-surface contact property was used to model the

  10. Adaptive error detection for HDR/PDR brachytherapy: Guidance for decision making during real-time in vivo point dosimetry

    SciTech Connect

    Kertzscher, Gustavo Andersen, Claus E.; Tanderup, Kari

    2014-05-15

    Purpose: This study presents an adaptive error detection algorithm (AEDA) for real-timein vivo point dosimetry during high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy (BT) where the error identification, in contrast to existing approaches, does not depend on an a priori reconstruction of the dosimeter position. Instead, the treatment is judged based on dose rate comparisons between measurements and calculations of the most viable dosimeter position provided by the AEDA in a data driven approach. As a result, the AEDA compensates for false error cases related to systematic effects of the dosimeter position reconstruction. Given its nearly exclusive dependence on stable dosimeter positioning, the AEDA allows for a substantially simplified and time efficient real-time in vivo BT dosimetry implementation. Methods: In the event of a measured potential treatment error, the AEDA proposes the most viable dosimeter position out of alternatives to the original reconstruction by means of a data driven matching procedure between dose rate distributions. If measured dose rates do not differ significantly from the most viable alternative, the initial error indication may be attributed to a mispositioned or misreconstructed dosimeter (false error). However, if the error declaration persists, no viable dosimeter position can be found to explain the error, hence the discrepancy is more likely to originate from a misplaced or misreconstructed source applicator or from erroneously connected source guide tubes (true error). Results: The AEDA applied on twoin vivo dosimetry implementations for pulsed dose rate BT demonstrated that the AEDA correctly described effects responsible for initial error indications. The AEDA was able to correctly identify the major part of all permutations of simulated guide tube swap errors and simulated shifts of individual needles from the original reconstruction. Unidentified errors corresponded to scenarios where the dosimeter position was

  11. Non-contact measurement of carotid arterial stiffness by two-point heart-pulse laser detection

    NASA Astrophysics Data System (ADS)

    Benedetti, M.; Favalli, V.; Mariano, A.; Rebrova, N.; Consoli, A.; Ayadi, J.; Gilardi, L.; Perna, M.; Minzioni, P.; Arbustini, E.; Giuliani, G.

    2016-02-01

    Arterial stiffness (AS) is a recognized predictor of cardiovascular risk and mortality, and a potential marker for monitoring the beneficial effects of medical treatments for arterial diseases. AS is typically evaluated indirectly, by assessing the so called pulse wave velocity (PWV), i.e. the speed at which the pressure wave created by the heart contraction travels along the aorta and other arteries. PWV is generally measured using piezoelectric transducers, or via a complex ultrasound technique, but in both cases it requires a direct contact with the patient, which could also modify the measured parameters. In the EU project "NISTAS" (Non-invasive screening of the status of the vascular system) [1], we develop a contactless system allowing to measure the PWV thanks to a technology derived from laser triangulation devices. The measurement principle consists in the detection of the small (around 100μm) displacement of the neck skin, induced by the transit of the pressure wave in the carotid. By simultaneously measuring the displacement caused by the pulse wave in two distinct points along the carotid, the time required by the pressure wave to travel a certain distance can be measured, and the PWV can then be easily calculated. The chosen technique for the skin displacement measurement is laser triangulation in its 2D variant (i.e. "laser profilometry"), which is robust to slight movements of the target, it does not suffer from speckle-pattern signal fading, and it can be conveniently implemented using low-cost optical components. Two light lines, emitted by two blue LEDs are projected on the target (the patient's neck skin), and the skin displacement versus time is measured using a high-frame-rate CMOS camera. In this manuscript we present the results obtained by measuring the PWV of 10 volunteers. It is foreseen that this technique can become a simple and widespread point-of-care method for large-scale cardiovascular system screening over large populations.

  12. Protein Adsorption and Reorganization on Nanoparticles Probed by the Coffee-Ring Effect: Application to Single Point Mutation Detection.

    PubMed

    Devineau, Stéphanie; Anyfantakis, Manos; Marichal, Laurent; Kiger, Laurent; Morel, Mathieu; Rudiuk, Sergii; Baigl, Damien

    2016-09-14

    The coffee-ring effect denotes the accumulation of particles at the edge of an evaporating sessile drop pinned on a substrate. Because it can be detected by simple visual inspection, this ubiquitous phenomenon can be envisioned as a robust and cost-effective diagnostic tool. Toward this direction, here we systematically analyze the deposit morphology of drying drops containing polystyrene particles of different surface properties with various proteins (bovine serum albumin (BSA) and different forms of hemoglobin). We show that deposit patterns reveal information on both the adsorption of proteins onto particles and their reorganization following adsorption. By combining pattern analysis with adsorption isotherm and zeta potential measurements, we show that the suppression of the coffee-ring effect and the formation of a disk-shaped pattern is primarily associated with particle neutralization by protein adsorption. However, our findings also suggest that protein reorganization following adsorption can dramatically invert this tendency. Exposure of hydrophobic (respectively charged) residues can lead to disk (respectively ring) deposit morphologies independently of the global particle charge. Surface tension measurements and microscopic observations of the evaporating drops show that the determinant factor of the deposit morphology is the accumulation of particles at the liquid/gas interface during evaporation. This general behavior opens the possibility to probe protein adsorption and reorganization on particles by the analysis of the deposit patterns, the formation of a disk being the robust signature of particles rendered hydrophobic by protein adsorption. We show that this method is sensitive enough to detect a single point mutation in a protein, as demonstrated here by the distinct patterns formed by human native hemoglobin h-HbA and its mutant form h-HbS, which is responsible for sickle cell anemia. PMID:27562632

  13. Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics

    NASA Astrophysics Data System (ADS)

    Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan

    2011-03-01

    We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection.

  14. THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT: FIRST DETECTION OF HIGH-VELOCITY MILKY WAY BAR STARS

    SciTech Connect

    Nidever, David L.; Zasowski, Gail; Majewski, Steven R.; Beaton, Rachael L.; Wilson, John C.; Skrutskie, Michael F.; O'Connell, Robert W.; Bird, Jonathan; Schoenrich, Ralph; Johnson, Jennifer A.; Sellgren, Kris; Robin, Annie C.; Schultheis, Mathias; Martinez-Valpuesta, Inma; Gerhard, Ortwin; Shetrone, Matthew; Schiavon, Ricardo P.; Weiner, Benjamin; Schneider, Donald P.; Allende Prieto, Carlos; and others

    2012-08-20

    Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for {approx}4700 K/M-giant stars in the Milky Way (MW) bulge. These high-resolution (R {approx} 22, 500), high-S/N (>100 per resolution element), near-infrared (NIR; 1.51-1.70 {mu}m) spectra provide accurate RVs ({epsilon}{sub V} {approx} 0.2 km s{sup -1}) for the sample of stars in 18 Galactic bulge fields spanning -1 Degree-Sign -32 Degree-Sign . This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold ({sigma}{sub V} {approx} 30 km s{sup -1}), high-velocity peak (V{sub GSR} Almost-Equal-To +200 km s{sup -1}) is found to comprise a significant fraction ({approx}10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.

  15. A simple method for determination of carmine in food samples based on cloud point extraction and spectrophotometric detection.

    PubMed

    Heydari, Rouhollah; Hosseini, Mohammad; Zarabi, Sanaz

    2015-01-01

    In this paper, a simple and cost effective method was developed for extraction and pre-concentration of carmine in food samples by using cloud point extraction (CPE) prior to its spectrophotometric determination. Carmine was extracted from aqueous solution using Triton X-100 as extracting solvent. The effects of main parameters such as solution pH, surfactant and salt concentrations, incubation time and temperature were investigated and optimized. Calibration graph was linear in the range of 0.04-5.0 μg mL(-1) of carmine in the initial solution with regression coefficient of 0.9995. The limit of detection (LOD) and limit of quantification were 0.012 and 0.04 μg mL(-1), respectively. Relative standard deviation (RSD) at low concentration level (0.05 μg mL(-1)) of carmine was 4.8% (n=7). Recovery values in different concentration levels were in the range of 93.7-105.8%. The obtained results demonstrate the proposed method can be applied satisfactory to determine the carmine in food samples.

  16. Development and evaluation of NucliSens basic kit NASBA for diagnosis of parainfluenza virus infection with 'end-point' and 'real-time' detection.

    PubMed

    Hibbitts, Sam; Rahman, Amanna; John, Rhiannon; Westmoreland, Diana; Fox, Julie D

    2003-03-01

    New methods for the detection of human parainfluenza viruses (HPIVs) were developed. These were based on nucleic acid sequence-based amplification (NASBA) and utilised the NucliSens Basic Kit. Primers and probes were selected from the haemagglutinin neuraminidase (HN) gene of HPIV1, HPIV2 and HPIV3, and from the phosphoprotein (P) of HPIV4a and -4b. Synthetic RNA, titrated control virus stocks and respiratory specimens (n=44) were utilised to evaluate performance of the assays. Detection of NASBA products was by probe hybridisation and electrochemiluminescence (ECL) ('end-point' detection) or using molecular beacons ('real-time' detection). The assays using ECL detection proved to be both sensitive and specific. Typically, less than or equal to 100 RNA copies or one TCID(50) input was detectable with no cross-reaction between the specific HPIV assays and other respiratory viruses. Results for clinical samples were concordant with those obtained by 'conventional' procedures by classical viral diagnostic methods. 'Real-time' detection utilised probes specific for either HPIV1 or HPIV3 with similar performance characteristics to the assays with 'end-point' detection. The feasibility of multiplexing targets together was confirmed using a combined HPIV1 and HPIV3 assay with good results for ECL and molecular beacon detection on control material and clinical samples.

  17. A new rapid method for Clostridium difficile DNA extraction and detection in stool: toward point-of-care diagnostic testing.

    PubMed

    Freifeld, Alison G; Simonsen, Kari A; Booth, Christine S; Zhao, Xing; Whitney, Scott E; Karre, Teresa; Iwen, Peter C; Viljoen, Hendrik J

    2012-01-01

    We describe a new method for the rapid diagnosis of Clostridium difficile infection, with stool sample preparation and DNA extraction by heat and physical disruption in a single-use lysis microreactor (LMR), followed by a rapid PCR amplification step. All steps can be accomplished in <20 minutes overall. Gel electrophoresis is currently used to detect the amplification product, pending real-time availability with an ultra-rapid thermocycler. Compared with the dual enzyme immunoassay (EIA) screening test (C. diff Quik Chek Complete; Techlab, Blacksburg, VA), the novel LMR/PCR assay showed complete concordance with all glutamate dehydrogenase (GDH) results (GDH(+)/toxin(+), n = 48; GDH(-)/toxin(-), n = 81). All 69 stool samples with discordant EIA results (GDH(+)/toxin(-)) were tested by both the LMR/PCR assay and the loop-mediated isothermal amplification test (LAMP) (Illumigene C. difficile; Meridian Bioscience, Cincinnati, OH). In 64/69 EIA-discordant samples, LAMP and LMR/PCR results matched (both positive in 29 sample and both negative in 35 samples); in the remaining 5 samples, results were discrepant between the LAMP assay (all five negative) and the LMR/PCR assay (all 5 positive). Overall, LMR/PCR testing matched the current algorithm of EIA and/or LAMP reflex testing in 193/198 (97.5%) samples. The present proof-of-concept study suggests that the novel LMR/PCR technique described here may be developed as an inexpensive, rapid, and reliable point-of-care diagnostic test for C. difficile infection and other infectious diseases.

  18. Real-time attitude commanding to detect coverage gaps and generate high resolution point clouds for RSO shape characterization with a laser rangefinder

    NASA Astrophysics Data System (ADS)

    Nayak, M.; Beck, J.; Udrea, B.

    This paper expands on previous studies by the authors into 3D imaging with a single-beam laser rangefinder (LRF) by implementing real-time attitude maneuvers of a chaser satellite flying in relative orbit around a resident space object (RSO). Point clouds generated with an LRF are much sparser than those generated with an imaging LIDAR, making it difficult to autonomously distinguish between gaps in coverage and truly empty space. Furthermore, if both the attitude and the shape of the target RSO are unknown, it is particularly difficult to register a collection of LRF strike points together and detect gaps in strike point coverage in realtime. This paper presents the incorporation of a narrow field of-view (NFOV) camera that detects the strike point on the RSO and supplements LRF distance measurements with image data. This data is used to generate attitude command profiles that efficiently fill LRF coverage gaps and generate high density point clouds, thus maximizing coverage of an unknown RSO. Results obtained so far point the way to a real-time implementation of the algorithm. A method to detect and close gaps in LRF strike point coverage is presented first. Coverage gap detection is achieved using Voronoi diagrams, where Voronoi cells are centered at the LRF strike points. A three-part algorithm is used that 1) creates a 3D panoramic map from “ stitched” NFOV camera images; 2) correlates the areas of sparse LRF coverage to the map; and 3) generates attitude commands to close the coverage gaps. The map provides a consistent and reliable method to register positions of strike points relative to each other and to the NFOV image of the RSO without a priori knowledge of the RSO attitude. Using this algorithm, gaps and sparse areas in LRF coverage are covered with strike points, allowing for the generation of a higher-resolution point cloud than that obtained with preprogrammed attitude profiles. Attitude maneuvers can now be designed on-line in real-ti- e such

  19. Fiber optic sensor employing successively destroyed coupled points or reflectors for detecting shock wave speed and damage location

    DOEpatents

    Weiss, Jonathan D.

    1995-01-01

    A shock velocity and damage location sensor providing a means of measuring shock speed and damage location. The sensor consists of a long series of time-of-arrival "points" constructed with fiber optics. The fiber optic sensor apparatus measures shock velocity as the fiber sensor is progressively crushed as a shock wave proceeds in a direction along the fiber. The light received by a receiving means changes as time-of-arrival points are destroyed as the sensor is disturbed by the shock. The sensor may comprise a transmitting fiber bent into a series of loops and fused to a receiving fiber at various places, time-of-arrival points, along the receiving fibers length. At the "points" of contact, where a portion of the light leaves the transmitting fiber and enters the receiving fiber, the loops would be required to allow the light to travel backwards through the receiving fiber toward a receiving means. The sensor may also comprise a single optical fiber wherein the time-of-arrival points are comprised of reflection planes distributed along the fibers length. In this configuration, as the shock front proceeds along the fiber it destroys one reflector after another. The output received by a receiving means from this sensor may be a series of downward steps produced as the shock wave destroys one time-of-arrival point after another, or a nonsequential pattern of steps in the event time-of-arrival points are destroyed at any point along the sensor.

  20. Fiber optic sensor employing successively destroyed coupled points or reflectors for detecting shock wave speed and damage location

    DOEpatents

    Weiss, J.D.

    1995-08-29

    A shock velocity and damage location sensor providing a means of measuring shock speed and damage location is disclosed. The sensor consists of a long series of time-of-arrival ``points`` constructed with fiber optics. The fiber optic sensor apparatus measures shock velocity as the fiber sensor is progressively crushed as a shock wave proceeds in a direction along the fiber. The light received by a receiving means changes as time-of-arrival points are destroyed as the sensor is disturbed by the shock. The sensor may comprise a transmitting fiber bent into a series of loops and fused to a receiving fiber at various places, time-of-arrival points, along the receiving fibers length. At the ``points`` of contact, where a portion of the light leaves the transmitting fiber and enters the receiving fiber, the loops would be required to allow the light to travel backwards through the receiving fiber toward a receiving means. The sensor may also comprise a single optical fiber wherein the time-of-arrival points are comprised of reflection planes distributed along the fibers length. In this configuration, as the shock front proceeds along the fiber it destroys one reflector after another. The output received by a receiving means from this sensor may be a series of downward steps produced as the shock wave destroys one time-of-arrival point after another, or a nonsequential pattern of steps in the event time-of-arrival points are destroyed at any point along the sensor. 6 figs.

  1. An Automated Three-Dimensional Detection and Segmentation Method for Touching Cells by Integrating Concave Points Clustering and Random Walker Algorithm

    PubMed Central

    Gong, Hui; Chen, Shangbin; Zhang, Bin; Ding, Wenxiang; Luo, Qingming; Li, Anan

    2014-01-01

    Characterizing cytoarchitecture is crucial for understanding brain functions and neural diseases. In neuroanatomy, it is an important task to accurately extract cell populations' centroids and contours. Recent advances have permitted imaging at single cell resolution for an entire mouse brain using the Nissl staining method. However, it is difficult to precisely segment numerous cells, especially those cells touching each other. As presented herein, we have developed an automated three-dimensional detection and segmentation method applied to the Nissl staining data, with the following two key steps: 1) concave points clustering to determine the seed points of touching cells; and 2) random walker segmentation to obtain cell contours. Also, we have evaluated the performance of our proposed method with several mouse brain datasets, which were captured with the micro-optical sectioning tomography imaging system, and the datasets include closely touching cells. Comparing with traditional detection and segmentation methods, our approach shows promising detection accuracy and high robustness. PMID:25111442

  2. RF-Medisys: a radio frequency identification-based electronic medical record system for improving medical information accessibility and services at point of care.

    PubMed

    Ting, Jacky S L; Tsang, Albert H C; Ip, Andrew W H; Ho, George T S

    2011-01-01

    This paper presents an innovative electronic medical records (EMR) system, RF-MediSys, which can perform medical information sharing and retrieval effectively and which is accessible via a 'smart' medical card. With such a system, medical diagnoses and treatment decisions can be significantly improved when compared with the conventional practice of using paper medical records systems. Furthermore, the entire healthcare delivery process, from registration to the dispensing or administration of medicines, can be visualised holistically to facilitate performance review. To examine the feasibility of implementing RF-MediSys and to determine its usefulness to users of the system, a survey was conducted within a multi-disciplinary medical service organisation that operates a network of medical clinics and paramedical service centres throughout Hong Kong Island, the Kowloon Peninsula and the New Territories. Questionnaires were distributed to 300 system users, including nurses, physicians and patients, to collect feedback on the operation and performance of RF-MediSys in comparison with conventional paper-based medical record systems. The response rate to the survey was 67%. Results showed a medium to high level of user satisfaction with the radiofrequency identification (RFID)-based EMR system. In particular, respondents provided high ratings on both 'user-friendliness' and 'system performance'. Findings of the survey highlight the potential of RF-MediSys as a tool to enhance quality of medical services and patient safety. PMID:21430306

  3. Information-theoretic analysis of x-ray photoabsorption based threat detection system for check-point

    NASA Astrophysics Data System (ADS)

    Lin, Yuzhang; Allouche, Genevieve G.; Huang, James; Ashok, Amit; Gong, Qian; Coccarelli, David; Stoian, Razvan-Ionut; Gehm, Michael E.

    2016-05-01

    In this work we present an information-theoretic framework for a systematic study of checkpoint x-ray systems using photoabsorption measurements. Conventional system performance analysis of threat detection systems confounds the effect of the system architecture choice with the performance of a threat detection algorithm. However, our system analysis approach enables a direct comparison of the fundamental performance limits of disparate hardware architectures, independent of the choice of a specific detection algorithm. We compare photoabsorptive measurements from different system architectures to understand the affect of system geometry (angular views) and spectral resolution on the fundamental limits of the system performance.

  4. Impact of the single point of access referral system to reduce waiting times and improve clinical outcomes in an assistive technology service.

    PubMed

    Hosking, Jonathan; Gibson, Colin

    2016-07-01

    The introduction of a single point referral system that prioritises clients depending on case complexity and overcomes the need for re-admittance to a waiting list via a review system has been shown to significantly reduce maximum waiting times for a Posture and Mobility (Special Seating) Service from 102.0 ± 24.33 weeks to 19.2 ± 8.57 weeks (p = 0.015). Using this service model linear regression revealed a statistically significant improvement in the performance outcome of prescribed seating solutions with shorter Episode of Care completion times (p = 0.023). In addition, the number of Episodes of Care completed per annum was significantly related to the Episode of Care completion time (p = 0.019). In conclusion, it is recommended that it may be advantageous to apply this service model to other assistive technology services in order to reduce waiting times and to improve clinical outcomes. PMID:27098983

  5. Joint detection of anatomical points on surface meshes and color images for visual registration of 3D dental models

    NASA Astrophysics Data System (ADS)

    Destrez, Raphaël.; Albouy-Kissi, Benjamin; Treuillet, Sylvie; Lucas, Yves

    2015-04-01

    Computer aided planning for orthodontic treatment requires knowing occlusion of separately scanned dental casts. A visual guided registration is conducted starting by extracting corresponding features in both photographs and 3D scans. To achieve this, dental neck and occlusion surface are firstly extracted by image segmentation and 3D curvature analysis. Then, an iterative registration process is conducted during which feature positions are refined, guided by previously found anatomic edges. The occlusal edge image detection is improved by an original algorithm which follows Canny's poorly detected edges using a priori knowledge of tooth shapes. Finally, the influence of feature extraction and position optimization is evaluated in terms of the quality of the induced registration. Best combination of feature detection and optimization leads to a positioning average error of 1.10 mm and 2.03°.

  6. Minimizing antibody cross-reactivity in multiplex detection of biomarkers in paper-based point-of-care assays.

    PubMed

    Dias, J T; Lama, L; Gantelius, J; Andersson-Svahn, H

    2016-04-21

    Highly multiplexed immunoassays could allow convenient screening of hundreds or thousands of protein biomarkers simultaneously in a clinical sample such as serum or plasma, potentially allowing improved diagnostic accuracy and clinical management of many conditions such as autoimmune disorders, infections, and several cancers. Currently, antibody microarray-based tests are limited in part due to cross reactivity from detection antibody reagents. Here we present a strategy that reduces the cross-reactivity between nanoparticle-bound reporter antibodies through the application of ultrasound energy. By this concept, it was possible to achieve a sensitivity 10(3)-fold (5 pg mL(-1)) lower than when no ultrasound was applied (50 ng mL(-1)) for the simultaneous detection of three different antigens. The detection limits and variability achieved with this technique rival those obtained with other types of multiplex sandwich assays. PMID:27030365

  7. Minimizing antibody cross-reactivity in multiplex detection of biomarkers in paper-based point-of-care assays

    NASA Astrophysics Data System (ADS)

    Dias, J. T.; Lama, L.; Gantelius, J.; Andersson-Svahn, H.

    2016-04-01

    Highly multiplexed immunoassays could allow convenient screening of hundreds or thousands of protein biomarkers simultaneously in a clinical sample such as serum or plasma, potentially allowing improved diagnostic accuracy and clinical management of many conditions such as autoimmune disorders, infections, and several cancers. Currently, antibody microarray-based tests are limited in part due to cross reactivity from detection antibody reagents. Here we present a strategy that reduces the cross-reactivity between nanoparticle-bound reporter antibodies through the application of ultrasound energy. By this concept, it was possible to achieve a sensitivity 103-fold (5 pg mL-1) lower than when no ultrasound was applied (50 ng mL-1) for the simultaneous detection of three different antigens. The detection limits and variability achieved with this technique rival those obtained with other types of multiplex sandwich assays.Highly multiplexed immunoassays could allow convenient screening of hundreds or thousands of protein biomarkers simultaneously in a clinical sample such as serum or plasma, potentially allowing improved diagnostic accuracy and clinical management of many conditions such as autoimmune disorders, infections, and several cancers. Currently, antibody microarray-based tests are limited in part due to cross reactivity from detection antibody reagents. Here we present a strategy that reduces the cross-reactivity between nanoparticle-bound reporter antibodies through the application of ultrasound energy. By this concept, it was possible to achieve a sensitivity 103-fold (5 pg mL-1) lower than when no ultrasound was applied (50 ng mL-1) for the simultaneous detection of three different antigens. The detection limits and variability achieved with this technique rival those obtained with other types of multiplex sandwich assays. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr09207h

  8. The Pan Genera Detection Immunoassay: a Novel Point-of-Issue Method for Detection of Bacterial Contamination in Platelet Concentrates ▿

    PubMed Central

    Vollmer, Tanja; Hinse, Dennis; Kleesiek, Knut; Dreier, Jens

    2010-01-01

    Bacterial contamination of platelet concentrates (PCs) still represents an ongoing risk in transfusion-transmitted sepsis. Recently the Pan Genera Detection (PGD) system was developed and FDA licensed for screening of bacterial contamination of PCs directly prior to transfusion. The test principle is based on the immunological detection of lipopolysaccharide (for Gram-negative bacteria) or lipoteichoic acid (for Gram-positive bacteria). In the present study we analyzed the applicability of this method with regard to detection limit, practicability, implementation, and performance. PCs were spiked with Staphylococcus aureus, Bacillus subtilis, and five different Klebsiella pneumoniae strains, as well as eight different Escherichia coli strains. The presence of bacteria was assessed by the PGD immunoassay, and bacteria were enumerated by plating cultures. Application of the PGD immunoassay showed that it is a rapid test with a short hands-on time for sample processing and no demand for special technical equipment and instrument operation. The lower detection limits of the assay for Gram-positive bacteria showed a good agreement with the manufacturer's specifications (8.2 × 103 to 5.5 × 104 CFU/ml). For some strains of K. pneumoniae and E. coli, the PGD test showed analytical sensitivities (>106 CFU/ml) that were divergent from the designated values (K. pneumoniae, 2.0 × 104 CFU/ml; E. coli, 2.8 × 104 CFU/ml). Result interpretation is sometimes difficult due to very faint bands. In conclusion, our study demonstrates that the PGD immunoassay is an easy-to-perform bedside test for the detection of bacterial contamination in PCs. However, to date there are some shortcomings in the interpretation of results and in the detection limits for some strains of Gram-negative bacteria. PMID:20702673

  9. Detecting the local transport properties and the dimensionality of transport of epitaxial graphene by a multi-point probe approach

    NASA Astrophysics Data System (ADS)

    Barreto, Lucas; Perkins, Edward; Johannsen, Jens; Ulstrup, Søren; Fromm, Felix; Raidel, Christian; Seyller, Thomas; Hofmann, Philip

    2013-01-01

    The electronic transport properties of epitaxial monolayer graphene (MLG) and hydrogen-intercalated quasi free-standing bilayer graphene (QFBLG) on SiC(0001) are investigated by micro multi-point probes. Using a probe with 12 contacts, we perform four-point probe measurements with the possibility to effectively vary the contact spacing over more than one order of magnitude, allowing us to establish that the transport is purely two-dimensional. Combined with the carrier density obtained by angle-resolved photoemission spectroscopy, we find the room temperature mobility of MLG to be (870±120) cm2/V s. The transport in QFBLG is also found to be two-dimensional with a mobility of (1600±160) cm2/V s.

  10. Suppression of optical beat interference-noise in orthogonal frequency division multiple access-passive optical network link using self-homodyne balanced detection

    NASA Astrophysics Data System (ADS)

    Won, Yong-Yuk; Jung, Sang-Min; Han, Sang-Kook

    2014-08-01

    A new technique, which reduces optical beat interference (OBI) noise in orthogonal frequency division multiple access-passive optical network (OFDMA-PON) links, is proposed. A self-homodyne balanced detection, which uses a single laser for the optical line terminal (OLT) as well as for the optical network unit (ONU), reduces OBI noise and also improves the signal to noise ratio (SNR) of the discrete multi-tone (DMT) signal. The proposed scheme is verified by transmitting quadrature phase shift keying (QPSK)-modulated DMT signal over a 20-km single mode fiber. The optical signal to noise ratio (OSNR), that is required for BER of 10-5, is reduced by 2 dB in the balanced detection compared with a single channel due to the cancellation of OBI noise in conjunction with the local laser.

  11. Point-Counterpoint: A Nucleic Acid Amplification Test for Streptococcus pyogenes Should Replace Antigen Detection and Culture for Detection of Bacterial Pharyngitis.

    PubMed

    Pritt, Bobbi S; Patel, Robin; Kirn, Thomas J; Thomson, Richard B

    2016-10-01

    Nucleic acid amplification tests (NAATs) have frequently been the standard diagnostic approach when specific infectious agents are sought in a clinic specimen. They can be applied for specific agents such as S. pyogenes, or commercial multiplex NAATs for detection of a variety of pathogens in gastrointestinal, bloodstream, and respiratory infections may be used. NAATs are both rapid and sensitive. For many years, S. pyogenes testing algorithms used a rapid and specific group A streptococcal antigen test to screen throat specimens, followed, in some clinical settings, by a throat culture for S. pyogenes to increase the sensitivity of its detection. Now S. pyogenes NAATs are being used with increasing frequency. Given their accuracy, rapidity, and ease of use, should they replace antigen detection and culture for the detection of bacterial pharyngitis? Bobbi Pritt and Robin Patel of the Mayo Clinic, where S. pyogenes NAATs have been used for well over a decade with great success, will explain the advantages of this approach, while Richard (Tom) Thomson and Tom Kirn of the NorthShore University HealthSystem will discuss their concerns about this approach to diagnosing bacterial pharyngitis.

  12. Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system.

    PubMed

    Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

    2007-02-01

    We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

  13. Visual Detection of Human Antibodies Using Sugar Chain-Immobilized Fluorescent Nanoparticles: Application as a Point of Care Diagnostic Tool for Guillain-Barré Syndrome.

    PubMed

    Shinchi, Hiroyuki; Yuki, Nobuhiro; Ishida, Hideharu; Hirata, Koichi; Wakao, Masahiro; Suda, Yasuo

    2015-01-01

    Sugar chain binding antibodies have gained substantial attention as biomarkers due to their crucial roles in various disorders. In this study, we developed simple and quick detection method of anti-sugar chain antibodies in sera using our previously developed sugar chain-immobilized fluorescent nanoparticles (SFNPs) for the point-of-care diagnostics. Sugar chain structure on SFNPs was modified with the sugar moieties of the GM1 ganglioside via our original linker molecule to detect anti-GM1 antibodies. The structures and densities of the sugar moieties immobilized on the nanoparticles were evaluated in detail using lectins and sera containing anti-GM1 antibodies from patients with Guillain-Barré syndrome, a neurological disorder, as an example of disease involving anti-sugar chain antibodies. When optimized SFNPs were added to sera from patients with Guillain-Barré syndrome, fluorescent aggregates were able to visually detect under UV light in three hours. The sensitivity of the detection method was equivalent to that of the current ELISA method used for the diagnosis of Guillain-Barré syndrome. These results suggest that our method using SFNPs is suitable for the point-of-care diagnostics of diseases involving anti-sugar chain antibodies.

  14. Visual Detection of Human Antibodies Using Sugar Chain-Immobilized Fluorescent Nanoparticles: Application as a Point of Care Diagnostic Tool for Guillain-Barré Syndrome

    PubMed Central

    Shinchi, Hiroyuki; Yuki, Nobuhiro; Ishida, Hideharu; Hirata, Koichi; Wakao, Masahiro; Suda, Yasuo

    2015-01-01

    Sugar chain binding antibodies have gained substantial attention as biomarkers due to their crucial roles in various disorders. In this study, we developed simple and quick detection method of anti-sugar chain antibodies in sera using our previously developed sugar chain-immobilized fluorescent nanoparticles (SFNPs) for the point-of-care diagnostics. Sugar chain structure on SFNPs was modified with the sugar moieties of the GM1 ganglioside via our original linker molecule to detect anti-GM1 antibodies. The structures and densities of the sugar moieties immobilized on the nanoparticles were evaluated in detail using lectins and sera containing anti-GM1 antibodies from patients with Guillain-Barré syndrome, a neurological disorder, as an example of disease involving anti-sugar chain antibodies. When optimized SFNPs were added to sera from patients with Guillain-Barré syndrome, fluorescent aggregates were able to visually detect under UV light in three hours. The sensitivity of the detection method was equivalent to that of the current ELISA method used for the diagnosis of Guillain-Barré syndrome. These results suggest that our method using SFNPs is suitable for the point-of-care diagnostics of diseases involving anti-sugar chain antibodies. PMID:26378448

  15. An insulated isothermal PCR method on a field-deployable device for rapid and sensitive detection of canine parvovirus type 2 at points of need.

    PubMed

    Wilkes, Rebecca P; Lee, Pei-Yu A; Tsai, Yun-Long; Tsai, Chuan-Fu; Chang, Hsiu-Hui; Chang, Hsiao-Fen G; Wang, Hwa-Tang T

    2015-08-01

    Canine parvovirus type 2 (CPV-2), including subtypes 2a, 2b and 2c, causes an acute enteric disease in both domestic and wild animals. Rapid and sensitive diagnosis aids effective disease management at points of need (PON). A commercially available, field-deployable and user-friendly system, designed with insulated isothermal PCR (iiPCR) technology, displays excellent sensitivity and specificity for nucleic acid detection. An iiPCR method was developed for on-site detection of all circulating CPV-2 strains. Limit of detection was determined using plasmid DNA. CPV-2a, 2b and 2c strains, a feline panleukopenia virus (FPV) strain, and nine canine pathogens were tested to evaluate assay specificity. Reaction sensitivity and performance were compared with an in-house real-time PCR using serial dilutions of a CPV-2b strain and 100 canine fecal clinical samples collected from 2010 to 2014, respectively. The 95% limit of detection of the iiPCR method was 13 copies of standard DNA and detection limits for CPV-2b DNA were equivalent for iiPCR and real-time PCR. The iiPCR reaction detected CPV-2a, 2b and 2c and FPV. Non-targeted pathogens were not detected. Test results of real-time PCR and iiPCR from 99 fecal samples agreed with each other, while one real-time PCR-positive sample tested negative by iiPCR. Therefore, excellent agreement (k = 0.98) with sensitivity of 98.41% and specificity of 100% in detecting CPV-2 in feces was found between the two methods. In conclusion, the iiPCR system has potential to serve as a useful tool for rapid and accurate PON, molecular detection of CPV-2.

  16. First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application

    SciTech Connect

    Lordi, V; Aberg, D; Erhart, P; Wu, K J

    2007-07-30

    The development of high resolution, room temperature semiconductor radiation detectors requires the introduction of materials with increased carrier mobility-lifetime ({mu}{tau}) product, while having a band gap in the 1.4-2.2 eV range. AlSb is a promising material for this application. However, systematic improvements in the material quality are necessary to achieve an adequate {mu}{tau} product. We are using a combination of simulation and experiment to develop a fundamental understanding of the factors which affect detector material quality. First principles calculations are used to study the microscopic mechanisms of mobility degradation from point defects and to calculate the intrinsic limit of mobility from phonon scattering. We use density functional theory (DFT) to calculate the formation energies of native and impurity point defects, to determine their equilibrium concentrations as a function of temperature and charge state. Perturbation theory via the Born approximation is coupled with Boltzmann transport theory to calculate the contribution toward mobility degradation of each type of point defect, using DFT-computed carrier scattering rates. A comparison is made to measured carrier concentrations and mobilities from AlSb crystals grown in our lab. We find our predictions in good quantitative agreement with experiment, allowing optimized annealing conditions to be deduced. A major result is the determination of oxygen impurity as a severe mobility killer, despite the ability of oxygen to compensation dope AlSb and reduce the net carrier concentration. In this case, increased resistivity is not a good indicator of improved material performance, due to the concomitant sharp reduction in {mu}{tau}.

  17. Kinetic detection of the end-point in titrations involving slow reactions Direct titration of polyhydroxy-compounds with periodate.

    PubMed

    Efstathiou, C E; Hadjiioannou, T P

    1983-03-01

    A new titration technique is described in which the end-point is determined by measuring the relative reaction rate of the titration reaction. This technique is adequate for rather slow reactions where conventional direct titrations are not applicable. The titrations are done automatically under microcomputer control. The efficiency of this technique is demonstrated with direct titrations of certain polyhydroxy-compounds with standard periodate solution. Ethylene glycol and propylene glycol (0.05-0.3 mmole), glycerol (0.06-0.17 mmole) and mannitol (0.01-0.03 mmole) were determined with average relative errors of 0.1-0.3%.

  18. Lunar laser ranging data deposited in the National Space Science Data Center normal points, filtered observations, and unfiltered photon detections

    NASA Technical Reports Server (NTRS)

    Shelus, P. J.

    1979-01-01

    The lunar laser ranging project at McDonald Observatory provides the unique opportunity to acquire successfully precise range data for the earth-moon system. From the experiment's inception, the obligation was recognized to make these data available to the general scientific community in a reasonably useable form and in a realistic time frame. The documentation to be used in conjunction with the 1979 April deposit into the National Space Science Data Center which contains normal points, filtered observations and unfiltered photon stops for the months July through December, 1978 are reported.

  19. Electrochemical sensing method for point-of-care cortisol detection in human immunodeficiency virus-infected patients.

    PubMed

    Kaushik, Ajeet; Yndart, Adriana; Jayant, Rahul Dev; Sagar, Vidya; Atluri, Venkata; Bhansali, Shekhar; Nair, Madhavan

    2015-01-01

    A novel electrochemical sensing method was devised for the first time to detect plasma cortisol, a potential psychological stress biomarker, in human immunodeficiency virus (HIV)-positive subjects. A miniaturized potentiostat (reconfigured LMP91000 chip) interfaced with a microfluidic manifold containing a cortisol immunosensor was employed to demonstrate electrochemical cortisol sensing. This fully integrated and optimized electrochemical sensing device exhibited a wide cortisol-detection range from 10 pg/mL to 500 ng/mL, a low detection limit of 10 pg/mL, and sensitivity of 5.8 μA (pg mL)(-1), with a regression coefficient of 0.995. This cortisol-selective sensing system was employed to estimate plasma cortisol in ten samples from HIV patients. The electrochemical cortisol-sensing performance was validated using an enzyme-linked immunosorbent assay technique. The results obtained using both methodologies were comparable within 2%-5% variation. The information related to psychological stress of HIV patients can be correlated with disease-progression parameters to optimize diagnosis, therapeutic, and personalized health monitoring. PMID:25632229

  20. Electrochemical sensing method for point-of-care cortisol detection in human immunodeficiency virus-infected patients

    PubMed Central

    Kaushik, Ajeet; Yndart, Adriana; Jayant, Rahul Dev; Sagar, Vidya; Atluri, Venkata; Bhansali, Shekhar; Nair, Madhavan

    2015-01-01

    A novel electrochemical sensing method was devised for the first time to detect plasma cortisol, a potential psychological stress biomarker, in human immunodeficiency virus (HIV)-positive subjects. A miniaturized potentiostat (reconfigured LMP91000 chip) interfaced with a microfluidic manifold containing a cortisol immunosensor was employed to demonstrate electrochemical cortisol sensing. This fully integrated and optimized electrochemical sensing device exhibited a wide cortisol-detection range from 10 pg/mL to 500 ng/mL, a low detection limit of 10 pg/mL, and sensitivity of 5.8 μA (pg mL)−1, with a regression coefficient of 0.995. This cortisol-selective sensing system was employed to estimate plasma cortisol in ten samples from HIV patients. The electrochemical cortisol-sensing performance was validated using an enzyme-linked immunosorbent assay technique. The results obtained using both methodologies were comparable within 2%–5% variation. The information related to psychological stress of HIV patients can be correlated with disease-progression parameters to optimize diagnosis, therapeutic, and personalized health monitoring. PMID:25632229

  1. An Energy-Based Approach for Detection and Characterization of Subtle Entities Within Laser Scanning Point-Clouds

    NASA Astrophysics Data System (ADS)

    Arav, Reuma; Filin, Sagi

    2016-06-01

    Airborne laser scans present an optimal tool to describe geomorphological features in natural environments. However, a challenge arises in the detection of such phenomena, as they are embedded in the topography, tend to blend into their surroundings and leave only a subtle signature within the data. Most object-recognition studies address mainly urban environments and follow a general pipeline where the data are partitioned into segments with uniform properties. These approaches are restricted to man-made domain and are capable to handle limited features that answer a well-defined geometric form. As natural environments present a more complex set of features, the common interpretation of the data is still manual at large. In this paper, we propose a data-aware detection scheme, unbound to specific domains or shapes. We define the recognition question as an energy optimization problem, solved by variational means. Our approach, based on the level-set method, characterizes geometrically local surfaces within the data, and uses these characteristics as potential field for minimization. The main advantage here is that it allows topological changes of the evolving curves, such as merging and breaking. We demonstrate the proposed methodology on the detection of collapse sinkholes.

  2. Preponderance of toxigenic Escherichia coli in stool pathogens correlates with toxin detection in accessible drinking-water sources.

    PubMed

    Igbokwe, H; Bhattacharyya, S; Gradus, S; Khubbar, M; Griswold, D; Navidad, J; Igwilo, C; Masson-Meyers, D; Azenabor, A A

    2015-02-01

    Since early detection of pathogens and their virulence factors contribute to intervention and control strategies, we assessed the enteropathogens in diarrhoea disease and investigated the link between toxigenic strains of Escherichia coli from stool and drinking-water sources; and determined the expression of toxin genes by antibiotic-resistant E. coli in Lagos, Nigeria. This was compared with isolates from diarrhoeal stool and water from Wisconsin, USA. The new Luminex xTAG GPP (Gastroplex) technique and conventional real-time PCR were used to profile enteric pathogens and E. coli toxin gene isolates, respectively. Results showed the pathogen profile of stool and indicated a relationship between E. coli toxin genes in water and stool from Lagos which was absent in Wisconsin isolates. The Gastroplex technique was efficient for multiple enteric pathogens and toxin gene detection. The co-existence of antibiotic resistance with enteroinvasive E. coli toxin genes suggests an additional prognostic burden on patients.

  3. Total Acid Value Titration of Hydrotreated Biomass Fast Pyrolysis Oil: Determination of Carboxylic Acids and Phenolics with Multiple End-Point Detection

    SciTech Connect

    Christensen, E.; Alleman, T. L.; McCormick, R. L.

    2013-01-01

    Total acid value titration has long been used to estimate corrosive potential of petroleum crude oil and fuel oil products. The method commonly used for this measurement, ASTM D664, utilizes KOH in isopropanol as the titrant with potentiometric end point determination by pH sensing electrode and Ag/AgCl reference electrode with LiCl electrolyte. A natural application of the D664 method is titration of pyrolysis-derived bio-oil, which is a candidate for refinery upgrading to produce drop in fuels. Determining the total acid value of pyrolysis derived bio-oil has proven challenging and not necessarily amenable to the methodology employed for petroleum products due to the different nature of acids present. We presented an acid value titration for bio-oil products in our previous publication which also utilizes potentiometry using tetrabutylammonium hydroxide in place of KOH as the titrant and tetraethylammonium bromide in place of LiCl as the reference electrolyte to improve the detection of these types of acids. This method was shown to detect numerous end points in samples of bio-oil that were not detected by D664. These end points were attributed to carboxylic acids and phenolics based on the results of HPLC and GC-MS studies. Additional work has led to refinement of the method and it has been established that both carboxylic acids and phenolics can be determined accurately. Use of pH buffer calibration to determine half-neutralization potentials of acids in conjunction with the analysis of model compounds has allowed us to conclude that this titration method is suitable for the determination of total acid value of pyrolysis oil and can be used to differentiate and quantify weak acid species. The measurement of phenolics in bio-oil is subject to a relatively high limit of detection, which may limit the utility of titrimetric methodology for characterizing the acidic potential of pyrolysis oil and products.

  4. Detection of protective antibody titers against feline panleukopenia virus, feline herpesvirus-1, and feline calicivirus in shelter cats using a point-of-care ELISA.

    PubMed

    Digangi, Brian A; Gray, Lauren K; Levy, Julie K; Dubovi, Edward J; Tucker, Sylvia J

    2011-12-01

    Serum antibody titers are a useful measurement of protection against infection (feline panleukopenia virus [FPV]) or clinical disease (feline herpesvirus-1 [FHV] and feline calicivirus [FCV]), and their determination has been recommended as part of disease outbreak management in animal shelters. The objective of this study was to determine the sensitivity, specificity, and inter-observer and inter-assay agreement of two semi-quantitative point-of-care assays for the detection of protective antibody titers (PAT) against FPV, FHV and FCV in shelter cats. Low sensitivity for FPV antibodies (28%) rendered a canine point-of-care assay inappropriate for use in cats. The feline point-of-care assay also had low sensitivity (49%) and low negative predictive value (74%) for FPV PAT detection, but was highly accurate in the assessment of FHV and FCV PAT. Improvements in accuracy and repeatability of FPV PAT determination could make this tool a valuable component of a disease outbreak response in animal shelters. PMID:21885311

  5. A novel one cycle allele specific primer extension--molecular beacon displacement method for DNA point mutation detection with improved specificity.

    PubMed

    Li, Xiaomin; Huang, Yong; Guan, Yuan; Zhao, Meiping; Li, Yuanzong

    2007-02-12

    We report here a new method for the real-time detection of DNA point mutations with molecular beacon as the fluorescence tracer and 3' (exo-) Bst DNA polymerase large fragment as the polymerase. The method is based on the mechanism of allele specific primer extension-strand displacement (ASPE-SD). To improve the specificity of the method only one cycle of the allele specific polymerase chain reaction (PCR) was used that could largely eliminate the non-specific reactions between the primers and template of the "wrong" genotype. At first, the primer and molecular beacon both hybridize to the DNA template, and the molecular beacon emits intensive fluorescence. The role of 3' exonuclease excision of Bst DNA polymerase large fragment is utilized for primer extension. When 3'-termini matches its corresponding template, the primer would efficiently extend and replace the molecular beacon that would simultaneously return to its closed form leading to the quenching of the fluorescence. However, when 3'-termini of the primer mismatches its corresponding template primer extension and molecular beacon displacement would not happen and fluorescence of the hybridized molecular beacon holds the line without fluorescence quenching. This approach was fully demonstrated in synthetic template systems and applied to detect point mutation at codon 259, a possible point mutation site in exon 7 of p53 gene, obtained from human genomic DNA samples with unambiguous differentiation power.

  6. A new method for change-point detection developed for on-line analysis of the heart beat variability during sleep

    NASA Astrophysics Data System (ADS)

    Staudacher, M.; Telser, S.; Amann, A.; Hinterhuber, H.; Ritsch-Marte, M.

    2005-04-01

    We present a novel scaling-dependent measure for times series analysis, the progressive detrended fluctuation analysis (PDFA). Since this method progressively includes and analyzes all data points of the time series, it is suitable for on-line change-point detection: Sudden changes in the statistics of the data points, in the type of correlation or in the statistical variance, or both, are reliably indicated and localized in time. This is first shown for numerous artificially generated data sets of Gaussian random numbers. Also time series with various non-stationarities, such as non-polynomial trends and “spiking”, are included as examples. Although generally applicable, our method was specifically developed as a tool for numerical sleep evaluation based on heart rate variability in the ECG-channel of polysomnographic whole night recordings. It is demonstrated that PDFA can detect specific sleep stage transitions, typically ascending transitions involving sympathetic activation as for example short episodes of wakefulness, and that the method is capable to discern between NREM sleep and REM sleep.

  7. Reference point indentation is insufficient for detecting alterations in traditional mechanical properties of bone under common experimental conditions.

    PubMed

    Krege, John B; Aref, Mohammad W; McNerny, Erin; Wallace, Joseph M; Organ, Jason M; Allen, Matthew R

    2016-06-01

    Reference point indentation (RPI) was developed as a novel method to assess mechanical properties of bone in vivo, yet it remains unclear what aspects of bone dictate changes/differences in RPI-based parameters. The main RPI parameter, indentation distance increase (IDI), has been proposed to be inversely related to the ability of bone to form/tolerate damage. The goal of this work was to explore the relationshipre-intervention RPI measurebetween RPI parameters and traditional mechanical properties under varying experimental conditions (drying and ashing bones to increase brittleness, demineralizing bones and soaking in raloxifene to decrease brittleness). Beams were machined from cadaveric bone, pre-tested with RPI, subjected to experimental manipulation, post-tested with RPI, and then subjected to four-point bending to failure. Drying and ashing significantly reduced RPI's IDI, as well as ultimate load (UL), and energy absorption measured from bending tests. Demineralization increased IDI with minimal change to bending properties. Ex vivo soaking in raloxifene had no effect on IDI but tended to enhance post-yield behavior at the structural level. These data challenge the paradigm of an inverse relationship between IDI and bone toughness, both through correlation analyses and in the individual experiments where divergent patterns of altered IDI and mechanical properties were noted. Based on these results, we conclude that RPI measurements alone, as compared to bending tests, are insufficient to reach conclusions regarding mechanical properties of bone. This proves problematic for the potential clinical use of RPI measurements in determining fracture risk for a single patient, as it is not currently clear that there is an IDI, or even a trend of IDI, that can determine clinically relevant changes in tissue properties that may contribute to whole bone fracture resistance. PMID:27072518

  8. Integrative volumetric bar-chart chip for rapid and quantitative point-of-care detection of myocardial infarction biomarkers.

    PubMed

    Song, Yujun; Wang, Yuzhen; Qi, Wenjin; Li, Ying; Xuan, Jie; Wang, Ping; Qin, Lidong

    2016-08-01

    Here we developed an integrated volumetric bar-chart chip (IV-Chip) technology by integration of our previous V-Chip with a fluid handling design to generate an instrument-free POC device and greatly reduce the detection time and effort. The IV-Chip test requires only 1 μL of serum separated from finger-prick blood. The serum sample and ELISA reagents are directly loaded into the device using a pipette, and a shift of the two layers of the device generates homogeneous liquid segments in the microfluidic channel. Under vacuum pressure generated by a regular syringe, the segments flow into the ELISA wells in sequence and a sandwich ELISA reaction takes place. As a result of the automated washing and reacting strategy, the IV-Chip allows rapid tests for myocardial infarction biomarkers, and turnaround time is greatly reduced to 15 min. The specificity and accuracy of quantitative multiplex detection of MI biomarkers CK-MB, troponin I and myoglobin, are 87.5% and 95.8%, respectively. PMID:27396992

  9. Genetic basis of human complement C4A deficiency. Detection of a point mutation leading to nonexpression.

    PubMed Central

    Barba, G; Rittner, C; Schneider, P M

    1993-01-01

    The fourth component of the human complement system (C4) is coded for by two genes, C4A and C4B, located within the MHC. Null alleles of C4 (C4Q0) are defined by the absence of C4 protein in plasma. These null alleles are due either to large gene deletions or to nonexpression of the respective genes. In a previous study, evidence was obtained for nonexpressed defective genes at the C4A locus, and for gene conversion at the C4B locus. To further characterize the molecular basis of these non-expressed C4A genes, we selected nine pairs of PCR primers from flanking genomic intron sequences to amplify all 41 exons from individuals with a defective C4A gene. The amplified products were subjected to single-stranded conformation polymorphism (SSCP) analysis to detect possible mutations. PCR products exhibiting a variation in the SSCP pattern were sequenced directly. In 10 of 12 individuals studied, we detected a 2-bp insertion in exon 29 leading to nonexpression due to the creation of a termination codon, which was observed in linkage to the haplotype HLA-B60-DR6 in seven cases. In one of the other two individuals without this mutation, evidence was obtained for gene conversion to the C4B isotype. The genetic basis of C4A nonexpression in the second individual is not yet known and will be subject to further analysis. Images PMID:8473511

  10. Plain to point network reduced graphene oxide-activated carbon composites decorated with platinum nanoparticles for urine glucose detection.

    PubMed

    Hossain, Mohammad Faruk; Park, Jae Y

    2016-01-01

    In this study, a hydrothermal technique was applied to synthesize glucose-treated reduced graphene oxide-activated carbon (GRGO/AC) composites. Platinum nanoparticles (PtNP) were electrochemically deposited on the modified GRGO/AC surface, and chitosan-glucose oxidase (Chit-GOx) composites and nafion were integrated onto the modified surface of the working electrode to prepare a highly sensitive glucose sensor. The fabricated biosensor exhibited a good amperometric response to glucose in the detection range from 0.002 mM to 10 mM, with a sensitivity of 61.06 μA/mMcm(2), a short response time (4 s) and a low detection limit of 2 μM (signal to noise ratio is 3). The glucose sensor exhibited a negligible response to interference and good stability. In addition, the glucose levels in human urine were tested in order to conduct a practical assessment of the proposed sensor, and the results indicate that the sensor had superior urine glucose recognition. These results thus demonstrate that the noble nano-structured electrode with a high surface area and electrocatalytic activity offers great promise for use in urine glucose sensing applications. PMID:26876368

  11. Plain to point network reduced graphene oxide - activated carbon composites decorated with platinum nanoparticles for urine glucose detection

    PubMed Central

    Hossain, Mohammad Faruk; Park, Jae Y.

    2016-01-01

    In this study, a hydrothermal technique was applied to synthesize glucose-treated reduced graphene oxide-activated carbon (GRGO/AC) composites. Platinum nanoparticles (PtNP) were electrochemically deposited on the modified GRGO/AC surface, and chitosan-glucose oxidase (Chit-GOx) composites and nafion were integrated onto the modified surface of the working electrode to prepare a highly sensitive glucose sensor. The fabricated biosensor exhibited a good amperometric response to glucose in the detection range from 0.002 mM to 10 mM, with a sensitivity of 61.06 μA/mMcm2, a short response time (4 s) and a low detection limit of 2 μM (signal to noise ratio is 3). The glucose sensor exhibited a negligible response to interference and good stability. In addition, the glucose levels in human urine were tested in order to conduct a practical assessment of the proposed sensor, and the results indicate that the sensor had superior urine glucose recognition. These results thus demonstrate that the noble nano-structured electrode with a high surface area and electrocatalytic activity offers great promise for use in urine glucose sensing applications. PMID:26876368

  12. Plain to point network reduced graphene oxide - activated carbon composites decorated with platinum nanoparticles for urine glucose detection

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Faruk; Park, Jae Y.

    2016-02-01

    In this study, a hydrothermal technique was applied to synthesize glucose-treated reduced graphene oxide-activated carbon (GRGO/AC) composites. Platinum nanoparticles (PtNP) were electrochemically deposited on the modified GRGO/AC surface, and chitosan-glucose oxidase (Chit-GOx) composites and nafion were integrated onto the modified surface of the working electrode to prepare a highly sensitive glucose sensor. The fabricated biosensor exhibited a good amperometric response to glucose in the detection range from 0.002 mM to 10 mM, with a sensitivity of 61.06 μA/mMcm2, a short response time (4 s) and a low detection limit of 2 μM (signal to noise ratio is 3). The glucose sensor exhibited a negligible response to interference and good stability. In addition, the glucose levels in human urine were tested in order to conduct a practical assessment of the proposed sensor, and the results indicate that the sensor had superior urine glucose recognition. These results thus demonstrate that the noble nano-structured electrode with a high surface area and electrocatalytic activity offers great promise for use in urine glucose sensing applications.

  13. A point-of-care testing system with Love-wave sensor and immunogold staining enhancement for early detection of lung cancer.

    PubMed

    Zou, Yingchang; Zhang, Xi; An, Chao; Ran, Chunxue; Ying, Kejing; Wang, Ping

    2014-12-01

    It has been reported that detection of exhaled breath condensate (EBC) is available for studies of pulmonary diseases, especially lung disease. In order to detect lung cancer (LC) at early stage, a point-of-care testing system suitable for measurement of tumor markers in EBC is developed. The assay, based on gold nanoparticle sandwich immunoassay and subsequent gold staining, was performed on a Love-wave sensor packaged inside a chip cartridge. Benefit from high sensitivity of Love-wave sensor, oriented immobilization of coating antibodies and immunogold staining enhancement, the present immunosensor could provide a sensitive, specific and rapid measurement. Carcinoembryonic antigen (CEA), neuron specific enolase (NSE) and squamous cell carcinoma antigen (SCC) in EBC collected from 17 patients with LC and 13 healthy volunteers were detected by this system. Results were compared with commercial chemiluminescence immunoassay and showed high correlation between two methods. Additionally, it revealed significantly statistical differences existing between two groups of subjects. These results indicate that the present system is suitable for detection of tumor markers in EBC and could be used as assistant tools for early detection of LC.

  14. Integration of cell phone imaging with microchip ELISA to detect ovarian cancer HE4 biomarker in urine at the point-of-care.

    PubMed

    Wang, Shuqi; Zhao, Xiaohu; Khimji, Imran; Akbas, Ragip; Qiu, Weiliang; Edwards, Dale; Cramer, Daniel W; Ye, Bin; Demirci, Utkan

    2011-10-21

    Ovarian cancer is asymptomatic in the early stages and most patients present with advanced levels of disease. The lack of cost-effective methods that can achieve frequent, simple and non-invasive testing hinders early detection and causes high mortality in ovarian cancer patients. Here, we report a simple and inexpensive microchip ELISA-based detection module that employs a portable detection system, i.e., a cell phone/charge-coupled device (CCD) to quantify an ovarian cancer biomarker, HE4, in urine. Integration of a mobile application with a cell phone enabled immediate processing of microchip ELISA results, which eliminated the need for a bulky, expensive spectrophotometer. The HE4 level detected by a cell phone or a lensless CCD system was significantly elevated in urine samples from cancer patients (n = 19) than healthy controls (n = 20) (p < 0.001). Receiver operating characteristic (ROC) analyses showed that the microchip ELISA coupled with a cell phone running an automated analysis mobile application had a sensitivity of 89.5% at a specificity of 90%. Under the same specificity, the microchip ELISA coupled with a CCD had a sensitivity of 84.2%. In conclusion, integration of microchip ELISA with cell phone/CCD-based colorimetric measurement technology can be used to detect HE4 biomarker at the point-of-care (POC), paving the way to create bedside technologies for diagnostics and treatment monitoring.

  15. SU-E-T-310: Targeting Safety Improvements Through Analysis of Near-Miss Error Detection Points in An Incident Learning Database

    SciTech Connect

    Novak, A; Nyflot, M; Sponseller, P; Howard, J; Logan, W; Holland, L; Jordan, L; Carlson, J; Ermoian, R; Kane, G; Ford, E; Zeng, J

    2014-06-01

    Purpose: Radiation treatment planning involves a complex workflow that can make safety improvement efforts challenging. This study utilizes an incident reporting system to identify detection points of near-miss errors, in order to guide our departmental safety improvement efforts. Previous studies have examined where errors arise, but not where they are detected or their patterns. Methods: 1377 incidents were analyzed from a departmental nearmiss error reporting system from 3/2012–10/2013. All incidents were prospectively reviewed weekly by a multi-disciplinary team, and assigned a near-miss severity score ranging from 0–4 reflecting potential harm (no harm to critical). A 98-step consensus workflow was used to determine origination and detection points of near-miss errors, categorized into 7 major steps (patient assessment/orders, simulation, contouring/treatment planning, pre-treatment plan checks, therapist/on-treatment review, post-treatment checks, and equipment issues). Categories were compared using ANOVA. Results: In the 7-step workflow, 23% of near-miss errors were detected within the same step in the workflow, while an additional 37% were detected by the next step in the workflow, and 23% were detected two steps downstream. Errors detected further from origination were more severe (p<.001; Figure 1). The most common source of near-miss errors was treatment planning/contouring, with 476 near misses (35%). Of those 476, only 72(15%) were found before leaving treatment planning, 213(45%) were found at physics plan checks, and 191(40%) were caught at the therapist pre-treatment chart review or on portal imaging. Errors that passed through physics plan checks and were detected by therapists were more severe than other errors originating in contouring/treatment planning (1.81 vs 1.33, p<0.001). Conclusion: Errors caught by radiation treatment therapists tend to be more severe than errors caught earlier in the workflow, highlighting the importance of safety

  16. Sensitivity of single-strand conformation polymorphism (SSCP) analysis in detecting p53 point mutations in tumors with mixed cell populations

    SciTech Connect

    Wu, J.K.; Zhen Ye; Darras, B.T. Tufts Univ., Boston, MA )

    1993-06-01

    Mutations in the p53 tumor-suppressor gene are commonly found in human cancers of diverse origin. Once of a number of methods developed to analyze large numbers of DNA samples for specific mutations is the single-strand conformation polymorphism (SSCP) analysis. This method is particularly well suited for analysis of tissues, such as brain tumors, with mixed cell populations. It takes advantage of the fact that, in a mixed cell population containing DNA with and without a mutation (e.g., the p53 gene mutation), both molecular species will be amplified by the PCR. A mutation within a PCR-amplified DNA fragment will alter the secondary structure of the amplified fragment and affect its electrophoretic mobility in a nondenaturing gel. The DNA fragments with the mutation are detected as an aberrantly migrating allele that can be seen concurrently with the wild-type allele. Although many studies have used this technique to screen for p53 mutations in tumors, with detection of a number of different mutations the limit of detection of point mutations in a background of wild-type DNA is not known. To test this, mixtures of mutant DNA from tumor D317 with a G-to-A point mutation in codon 272 of the p53 gene; or from tumor D263 (with a G-to-A point mutation in codon 175 of the p53 gene) and wild-type DNA from leukocytes, in ratios of 1:100, 5:95, 10:90, 15:85, 50:50, and 30:70, were prepared. The mixtures containing 100 ng of DNA were amplified using standard PCR technique. After the double-stranded DNAs were denatured, the DNA samples were loaded and electrophoresed on a nondenaturing acrylamide gel. The mutant allele was detectable even when the ratio of mutant to wild-type DNA was 5:95 in tumor D317. For tumor D263, the mutant allele was detectable when the ratio of mutant to wild-type DNA was 15:85, and it was not detectable at 10:90.

  17. Airborne Light Detection and Ranging (lidar) Derived Deformation from the MW 6.0 24 August, 2014 South Napa Earthquake Estimated by Two and Three Dimensional Point Cloud Change Detection Techniques

    NASA Astrophysics Data System (ADS)

    Lyda, A. W.; Zhang, X.; Glennie, C. L.; Hudnut, K.; Brooks, B. A.

    2016-06-01

    Remote sensing via LiDAR (Light Detection And Ranging) has proven extremely useful in both Earth science and hazard related studies. Surveys taken before and after an earthquake for example, can provide decimeter-level, 3D near-field estimates of land deformation that offer better spatial coverage of the near field rupture zone than other geodetic methods (e.g., InSAR, GNSS, or alignment array). In this study, we compare and contrast estimates of deformation obtained from different pre and post-event airborne laser scanning (ALS) data sets of the 2014 South Napa Earthquake using two change detection algorithms, Iterative Control Point (ICP) and Particle Image Velocimetry (PIV). The ICP algorithm is a closest point based registration algorithm that can iteratively acquire three dimensional deformations from airborne LiDAR data sets. By employing a newly proposed partition scheme, "moving window," to handle the large spatial scale point cloud over the earthquake rupture area, the ICP process applies a rigid registration of data sets within an overlapped window to enhance the change detection results of the local, spatially varying surface deformation near-fault. The other algorithm, PIV, is a well-established, two dimensional image co-registration and correlation technique developed in fluid mechanics research and later applied to geotechnical studies. Adapted here for an earthquake with little vertical movement, the 3D point cloud is interpolated into a 2D DTM image and horizontal deformation is determined by assessing the cross-correlation of interrogation areas within the images to find the most likely deformation between two areas. Both the PIV process and the ICP algorithm are further benefited by a presented, novel use of urban geodetic markers. Analogous to the persistent scatterer technique employed with differential radar observations, this new LiDAR application exploits a classified point cloud dataset to assist the change detection algorithms. Ground

  18. A smart device for label-free and real-time detection of gene point mutations based on the high dark phase contrast of vapor condensation.

    PubMed

    Zhang, Junqi; Fu, Rongxin; Xie, Liping; Li, Qi; Zhou, Wenhan; Wang, Ruliang; Ye, Jiancheng; Wang, Dong; Xue, Ning; Lin, Xue; Lu, Ying; Huang, Guoliang

    2015-10-01

    A smart device for label-free and real-time detection of gene point mutation-related diseases was developed based on the high dark phase contrast of vapor condensation. The main components of the device included a Peltier cooler and a mini PC board for image processing. Heat from the hot side of the Peltier cooler causes the fluid in a copper chamber to evaporate, and the vapor condenses on the surface of a microarray chip placed on the cold side of the cooler. The high dark phase contrast of vapor condensation relative to the analytes on the microarray chip was explored. Combined with rolling circle amplification, the device visualizes less-to-more hydrophilic transitions caused by gene trapping and DNA amplification. A lung cancer gene point mutation was analysed, proving the high selectivity and multiplex analysis capability of this low-cost device. PMID:26266399

  19. Optical fibre gas detections systems

    NASA Astrophysics Data System (ADS)

    Culshaw, Brian

    2016-05-01

    This tutorial review covers the principles of and prospects for fibre optic sensor technology in gas detection. Many of the potential benefits common to fibre sensor technology also apply in the context of gas sensing - notably long distance - many km - access to multiple remote measurement points; invariably intrinsic safety; access to numerous important gas species and often uniquely high levels of selectivity and/or sensitivity. Furthermore, the range of fibre sensor network architectures - single point, multiple point and distributed - enable unprecedented flexibility in system implementation. Additionally, competitive technologies and regulatory issues contribute to final application potential.

  20. Point-of-care detection and real-time monitoring of intravenously delivered drugs via tubing with an integrated SERS sensor

    NASA Astrophysics Data System (ADS)

    Wu, Hsin-Yu; Cunningham, Brian T.

    2014-04-01

    We demonstrate an approach for detection, identification, and kinetic monitoring of drugs flowing within tubing, through the use of a plasmonic nanodome array (PNA) surface. The PNA structures are fabricated using a low-cost nanoreplica molding process upon a flexible plastic substrate that is subsequently integrated with a flow cell that connects in series with ordinary intravenous (IV) drug delivery tubing. To investigate the potential clinical applications for point-of-care detection and real-time monitoring, we perform SERS detection of ten pharmaceutical compounds (hydrocodone, levorphanol, morphine, oxycodone, methadone, phenobarbital, dopamine, diltiazem, promethazine, and mitoxantrone). We demonstrate dose-dependent SERS signal magnitude, resulting in detection limits (ng ml-1) well below typical administered dosages (mg ml-1). Further, we show that the detected drugs are not permanently attached to the PNA surface, and thus our approach is capable of performing continuous monitoring of drug delivery as materials flow through IV tubing that is connected in series with the sensor. Finally, we demonstrate the potential co-detection of multiple drugs when they are mixed together, and show excellent reproducibility and stability of SERS measurements for periods extending at least five days. The capabilities reported here demonstrate the potential to use PNA SERS surfaces for enhancing the safety of IV drug delivery.We demonstrate an approach for detection, identification, and kinetic monitoring of drugs flowing within tubing, through the use of a plasmonic nanodome array (PNA) surface. The PNA structures are fabricated using a low-cost nanoreplica molding process upon a flexible plastic substrate that is subsequently integrated with a flow cell that connects in series with ordinary intravenous (IV) drug delivery tubing. To investigate the potential clinical applications for point-of-care detection and real-time monitoring, we perform SERS detection of ten

  1. Combination of a modified block PCR and endonuclease IV-based signal amplification system for ultra-sensitive detection of low-abundance point mutations.

    PubMed

    Xiao, Xianjin; Xu, Anqin; Zhai, Junqiu; Zhao, Meiping

    2013-12-15

    By combination of a modified block PCR and endonuclease IV-based signal amplification system, we have developed a novel approach for ultra-sensitive detection of point mutations. The method can effectively identify mutant target sequence immersed in a large background of wild-type sequences with abundance down to 0.03% (for C→A) and 0.005% (for C→G). This sensitivity is among the highest in comparison with other existing approaches and the operating procedures are simple and time saving. The method holds great potential for future application in clinical diagnosis and biomedical research.

  2. Point-of-care ultrasonography of the orbit for detection of retinal detachment in a patient with hemolysis, elevated liver enzymes, and low platelet count syndrome

    PubMed Central

    Shrestha, Gentle Sunder; Rajbhandari, Shayuja; Dhungel, Shashwat; Sharma, Nutan; Poudel, Nimesh; Manandhar, Dhiraj N.

    2016-01-01

    Retinal detachment is a rare, but well-known cause of visual impairment in patients with hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. With supportive care, patients usually improve, with complete recovery of vision. Bedside ultrasonography of the orbit can be helpful for early detection of retinal detachment in these patients. Here, we present a case of HELLP syndrome presenting with severe visual symptoms. Retinal detachment was detected with point-of-care ocular sonography, which was confirmed with ophthalmoscopic examination. The patient was reassured of the favorable prognosis. Early initiation of aggressive supportive care was followed by progressive improvement of vision, which correlated with sonographic evidence of resolution of detachment. Her vision recovered completely in 2 weeks. PMID:27688632

  3. Wavelet Transform Analysis of the Power Spectrum of Centre of Pressure Signals to Detect the Critical Point Interval of Postural Control

    NASA Astrophysics Data System (ADS)

    Singh, Neeraj Kumar; Snoussi, Hichem; Hewson, David; Duchêne, Jacques

    The aim of this study was to develop a method to detecting the critical point interval (CPI) when sensory feedback is used as part of a closed-loop postural control strategy. Postural balance was evaluated using centre of pressure (COP) displacements from a force plate for 17 control and 10 elderly subjects under eyes open, eyes closed, and vibration conditions. A modified local-maximum-modulus wavelet transform analysis using the power spectrum of COP signals was used to calculate CPI. Lower CPI values indicate increased closed-loop postural control with a quicker response to sensory input. Such a strategy requires greater energy expenditure due to the repeated muscular interventions to remain stable. The CPI for elderly occurred significantly quicker than for controls, indicating tighter control of posture. Similar results were observed for eyes closed and vibration conditions. The CPI parameter can be used to detect differences in postural control due to ageing.

  4. Validation of end-point and real-time PCR methods for the rapid detection of soy allergen in processed products.

    PubMed

    Espineira, Montserrat; Herrero, Beatriz; Vieites, Juan M; Santaclara, Francisco J

    2010-04-01

    This work describes the development and validation of two PCR methods, end-point and real-time PCR, for the detection of soy protein in a wide rage of foodstuffs. These techniques are reliable and sensitive, allowing detection of trace amounts of soybean in processed products. TaqMan real-time PCR was the simpler and more rapid process, with a higher potential for automation and, therefore, currently the most suitable screening method. To verify correct operation of the proposed methodology, ELISA was used for quantitative determination of soy protein. In addition, 35 meat, fish and bakery processed products, which could potentially contain soy but was not declared on the label, were tested for the presence of soy DNA using the proposed methods. The methodologies will be valuable in issues regarding the presence of soy protein in processed products, especially in verifying labelling and security regulations to protect consumer's rights.

  5. Point-of-care ultrasonography of the orbit for detection of retinal detachment in a patient with hemolysis, elevated liver enzymes, and low platelet count syndrome.

    PubMed

    Shrestha, Gentle Sunder; Rajbhandari, Shayuja; Dhungel, Shashwat; Sharma, Nutan; Poudel, Nimesh; Manandhar, Dhiraj N

    2016-09-01

    Retinal detachment is a rare, but well-known cause of visual impairment in patients with hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. With supportive care, patients usually improve, with complete recovery of vision. Bedside ultrasonography of the orbit can be helpful for early detection of retinal detachment in these patients. Here, we present a case of HELLP syndrome presenting with severe visual symptoms. Retinal detachment was detected with point-of-care ocular sonography, which was confirmed with ophthalmoscopic examination. The patient was reassured of the favorable prognosis. Early initiation of aggressive supportive care was followed by progressive improvement of vision, which correlated with sonographic evidence of resolution of detachment. Her vision recovered completely in 2 weeks. PMID:27688632

  6. The detection of pfcrt and pfmdr1 point mutations as molecular markers of chloroquine drug resistance, Pahang, Malaysia

    PubMed Central

    2012-01-01

    Background Malaria is still a public health problem in Malaysia with chloroquine (CQ) being the first-line drug in the treatment policy of uncomplicated malaria. There is a scarcity in information about the magnitude of Plasmodium falciparum CQ resistance. This study aims to investigate the presence of single point mutations in the P. falciparum chloroquine-resistance transporter gene (pfcrt) at codons 76, 271, 326, 356 and 371 and in P. falciparum multi-drug resistance-1 gene (pfmdr1) at codons 86 and 1246, as molecular markers of CQ resistance. Methods A total of 75 P. falciparum blood samples were collected from different districts of Pahang state, Malaysia. Single nucleotide polymorphisms in pfcrt gene (codons 76, 271, 326, 356 and 371) and pfmdr1 gene (codons 86 and 1246) were analysed by using mutation-specific nested PCR and restriction fragment length polymorphism (PCR-RFLP) methods. Results Mutations of pfcrt K76T and pfcrt R371I were the most prevalent among pfcrt gene mutations reported by this study; 52% and 77%, respectively. Other codons of the pfcrt gene and the positions 86 and 1246 of the pfmdr1 gene were found mostly of wild type. Significant associations of pfcrt K76T, pfcrt N326S and pfcrt I356T mutations with parasitaemia were also reported. Conclusion The high existence of mutant pfcrt T76 may indicate the low susceptibility of P. falciparum isolates to CQ in Peninsular Malaysia. The findings of this study establish baseline data on the molecular markers of P. falciparum CQ resistance, which may help in the surveillance of drug resistance in Peninsular Malaysia. PMID:22853645

  7. Spatial frequency characteristics at image decision-point locations for observers with different radiological backgrounds in lung nodule detection

    NASA Astrophysics Data System (ADS)

    Pietrzyk, Mariusz W.; Manning, David J.; Dix, Alan; Donovan, Tim

    2009-02-01

    Aim: The goal of the study is to determine the spatial frequency characteristics at locations in the image of overt and covert observers' decisions and find out if there are any similarities in different observers' groups: the same radiological experience group or the same accuracy scored level. Background: The radiological task is described as a visual searching decision making procedure involving visual perception and cognitive processing. Humans perceive the world through a number of spatial frequency channels, each sensitive to visual information carried by different spatial frequency ranges and orientations. Recent studies have shown that particular physical properties of local and global image-based elements are correlated with the performance and the level of experience of human observers in breast cancer and lung nodule detections. Neurological findings in visual perception were an inspiration for wavelet applications in vision research because the methodology tries to mimic the brain processing algorithms. Methods: The wavelet approach to the set of postero-anterior chest radiographs analysis has been used to characterize perceptual preferences observers with different levels of experience in the radiological task. Psychophysical methodology has been applied to track eye movements over the image, where particular ROIs related to the observers' fixation clusters has been analysed in the spaces frame by Daubechies functions. Results: Significance differences have been found between the spatial frequency characteristics at the location of different decisions.

  8. Accessibility Videos.

    PubMed

    Kurppa, Ari; Nordlund, Marika

    2016-01-01

    It can be difficult to understand accessibility, if you do not have the personal experience. The Accessibility Centre ESKE produced short videos which demonstrate the meaning of accessibility in different situations. Videos will raise accessibility awareness of architects, other planners and professionals in the construction field and maintenance. PMID:27534282

  9. Access to modern contraception.

    PubMed

    Welsh, Michael J; Stanback, John; Shelton, James

    2006-06-01

    Access to modern contraception has become a recognized human right, improving the health and well-being of women, families and societies worldwide. However, contraceptive access remains uneven. Irregular contraceptive supply, limited numbers of service delivery points and specific geographic, economic, informational, psychosocial and administrative barriers (including medical barriers) undermine access in many settings. Widening the range of providers enabled to offer contraception can improve contraceptive access, particularly where resources are most scarce. International efforts to remove medical barriers include the World Health Organization's Medical Eligibility Criteria. Based on the best available evidence, these criteria provide guidance for weighing the risks and benefits of contraceptive choice among women with specific clinical conditions. Clinical job aids can also improve access. More research is needed to further elucidate the pathways for expanding contraceptive access. Further progress in removing medical barriers will depend on systems for improving provider education and promoting evidence-based contraceptive service delivery. PMID:16443395

  10. Improving the sensitivity of confocal laser induced fluorescence detection to the sub-picomolar scale for round capillaries by laterally shifting the laser focus point.

    PubMed

    Zhu, Ying; Chen, Niannian; Li, Qi; Fang, Qun

    2013-08-21

    This paper describes a simple and efficient approach to reduce the background level of confocal laser induced fluorescence (LIF) detection for round capillaries by laterally shifting the laser focus point. A phenomenon of spontaneous separation of the fluorescence and reflected laser beams at the pinhole of a confocal LIF system when the laser focus point deviates from the center of a capillary channel to the sides was observed for the first time. On the basis of this phenomenon, the reflected laser light from the capillary-air interfaces could be mostly eliminated with a spatial filtering pinhole. A comprehensive study on the phenomenon and optimization of the shift distance was carried out using both experimental and simulation methods. A best shift distance of ±20 μm was obtained, with which background intensity could be significantly reduced by 98.9%, while fluorescence intensity was only reduced by 25.7%, resulting in an improvement of signal-to-noise ratio of 8.3 times, compared with that at a shift distance of 0 μm usually used in most of the confocal LIF systems for round capillaries. A limit of detection of 66 fM was obtained for sodium fluorescein. To demonstrate its potential as an on-column sensitive detector for microscale separation systems, the present system was coupled with a capillary electrophoresis system for separation of four fluorescein isothiocyanate labeled amino acids with concentrations of 100 pM.

  11. Dissolved organic matter fluorescence at wavelength 275/342 nm as a key indicator for detection of point-source contamination in a large Chinese drinking water lake.

    PubMed

    Zhou, Yongqiang; Jeppesen, Erik; Zhang, Yunlin; Shi, Kun; Liu, Xiaohan; Zhu, Guangwei

    2016-02-01

    Surface drinking water sources have been threatened globally and there have been few attempts to detect point-source contamination in these waters using chromophoric dissolved organic matter (CDOM) fluorescence. To determine the optimal wavelength derived from CDOM fluorescence as an indicator of point-source contamination in drinking waters, a combination of field campaigns in Lake Qiandao and a laboratory wastewater addition experiment was used. Parallel factor (PARAFAC) analysis identified six components, including three humic-like, two tryptophan-like, and one tyrosine-like component. All metrics showed strong correlation with wastewater addition (r(2) > 0.90, p < 0.0001). Both the field campaigns and the laboratory contamination experiment revealed that CDOM fluorescence at 275/342 nm was the most responsive wavelength to the point-source contamination in the lake. Our results suggest that pollutants in Lake Qiandao had the highest concentrations in the river mouths of upstream inflow tributaries and the single wavelength at 275/342 nm may be adapted for online or in situ fluorescence measurements as an early warning of contamination events. This study demonstrates the potential utility of CDOM fluorescence to monitor water quality in surface drinking water sources.

  12. A Multi-observer Study of the Effects of Including Point-of-care Patient Photographs with Portable Radiography: A Means to Detect Wrong-Patient Errors

    PubMed Central

    Tridandapani, Srini; Ramamurthy, Senthil; Provenzale, James; Obuchowski, Nancy A; Evanoff, Michael G.; Bhatti, Pamela

    2014-01-01

    Objectives To evaluate whether the presence of facial photographs obtained at the point-of-care of portable radiography leads to increased detection of wrong-patient errors. Materials and Methods In this IRB-approved study, 166 radiograph-photograph combinations were obtained from 30 patients. Consecutive radiographs from the same patients resulted in 83 unique pairs (i.e., a new radiograph and prior, comparison radiograph) for interpretation. To simulate wrong-patient errors, mismatched pairs were generated by pairing radiographs from different patients chosen randomly from the sample. Ninety radiologists each interpreted a unique randomly chosen set of 10 radiographic pairs, containing up to 10% mismatches (i.e., error pairs). Radiologists were randomly assigned to interpret radiographs with or without photographs. The number of mismatches identified and interpretation times were recorded. Results Ninety radiologists with 21 ± 10 (mean ± SD) years of experience were recruited to participate in this observer study. With the introduction of photographs, the proportion of errors detected increased from 31% (9/29) to 77% (23/30) (P = 0.006). The odds ratio for detection of error with photographs to detection without photographs was 7.3 (95% CI: 2.29, 23.18). Observer qualifications, training or practice in cardiothoracic radiology did not influence sensitivity for error detection. There is no significant difference in interpretation time for studies without photographs and those with photographs (60 ± 22 seconds vs 61 ± 25 seconds; P=0.77). Conclusion In this observer study, facial photographs obtained simultaneously with portable chest radiographs increased the identification of any wrong-patient errors, without substantial increase in interpretation time. This technique offers a potential means to increase patient safety through correct patient identification. PMID:25018076

  13. A scalable engineering approach to improve performance of a miniaturized optical detection system for in vitro point-of-care testing

    NASA Astrophysics Data System (ADS)

    Robbins, Hannah; Hu, Sijung; Liu, Changqing

    2015-03-01

    The demand for rapid screening technologies, to be used outside of a traditional healthcare setting, has been vastly expanding. This is requiring a new engineering platform for faster and cost effective techniques to be easily adopted through forward-thinking manufacturing procedures, i.e., advanced miniaturisation and heterogeneous integration of high performance microfluidics based point-of-care testing (POCT) systems. Although there has been a considerable amount of research into POCT systems, there exist tremendous challenges and bottlenecks in the design and manufacturing in order to reach a clinical acceptability of sensitivity and selectivity, as well as smart microsystems for healthcare. The project aims to research how to enable scalable production of such complex systems through 1) advanced miniaturisation of a physical layout and opto-electronic component allocation through an optimal design; and 2) heterogeneous integration of multiplexed fluorescence detection (MFD) for in vitro POCT. Verification is being arranged through experimental testing with a series of dilutions of commonly used fluorescence dye, i.e. Cy5. Iterative procedures will be engaged until satisfaction of the detection limit, of Cy5 dye, 1.209x10-10 M. The research creates a new avenue of rapid screening POCT manufacturing solutions with a particular view on high performance and multifunctional detection systems not only in POCT, but also life sciences and environmental applications.

  14. 3,4-Dihydroxy-l-phenylalanine as a biomarker of oxidative damage in proteins: improved detection using cloud-point extraction and HPLC.

    PubMed

    McPherson, Peter A C; Türemen, Bryn T

    2014-09-26

    Oxidized protein adducts are formed under conditions of oxidative stress and may represent a valuable biomarker for a variety of diseases which share this common aetiology. A suitable candidate biomarker for oxidized proteins is protein-bound 3,4-dihydroxyl-l-phenylalanine (l-DOPA), which is formed on 3'-hydroxylation of tyrosine residues by hydroxyl radicals. Existing methodologies to measure protein-bound l-DOPA employ lengthy acid hydrolysis steps (ca. 16h) which may cause artifactual protein oxidation, followed by HPLC with detection based on the intrinsic fluorescence of l-DOPA. We report a novel method for the measurement of protein-bound l-DOPA which involves rapid hydrolysis followed by pre-column concentration of 6-aminoquinolyl-derivatives using cloud-point extraction. The derivatized material is resolved by reversed-phase HPLC in less than 30min and has derivatization chemistry compatible with both UV and fluorescent detection, providing detection down to the femtomole level. The method provides identical results to those found with highly specific ELISA-based techniques and requires only basic instrumentation. The stability of the 6-aminoquinolyl-derivatives together with the fast and sensitive nature of the assay will be appealing to those who require large sample throughput.

  15. Laboratory Evaluation of a Point-of-Care Downward-Flow Assay for Simultaneous Detection of Antibodies to Treponema pallidum and Human Immunodeficiency Virus.

    PubMed

    Herbst de Cortina, S; Bristow, C C; Vargas, S K; Perez, D G; Konda, K A; Caceres, C F; Klausner, J D

    2016-07-01

    Combining the detection of syphilis and HIV antibodies into one point-of-care test integrates syphilis screening into already existing HIV screening programs, which may be particularly beneficial in settings such as antenatal care. Using the INSTI Multiplex downward-flow immunoassay, we tested 200 stored serum samples from high-risk patients enrolled in a longitudinal study on HIV infection and syphilis in Peruvian men who have sex with men and transgender women. This rapid assay detected HIV and Treponema pallidum serum antibodies with sensitivities of 100% (95% confidence interval [CI], 95.9% to 100%) and 87.4% (95% CI, 81.4% to 92.0%), respectively, and specificities of 95.5% (95% CI, 89.9% to 98.5%) and 97.0% (95% CI, 84.2% to 99.9%), respectively (n = 200). The sensitivity for syphilis antibody detection was higher in patients with a rapid plasma reagin titer of ≥1:8 (97.3%) than in those with a titer of ≤1:4 (90%) or a nonreactive titer (66.7%). PMID:27147725

  16. Highly sensitive DNA detection and point mutation identification: an electrochemical approach based on the combined use of ligase and reverse molecular beacon.

    PubMed

    Wu, Zai-Sheng; Jiang, Jian-Hui; Shen, Guo-Li; Yu, Ru-Qin

    2007-06-01

    A novel strategy is described for highly sensitive DNA detection and point mutation identification based on the combination of reverse molecular beacon with DNA ligase. A 5'-phosphoryl and 3'-ferrocene terminated DNA sequence is used as detection probe, which may be ligated to capture DNA immobilized on an electrode surface in the presence of a target DNA strand that is complementary to the ends of each DNA, since this allows formation of a nicked, double-stranded DNA. The ligation product may form a hairpin structure after the removal of target DNA. By this method, target DNA can be determined in the range from 3.4 x 10(-12) to 1.4 x 10(-7) M with a detection limit of 1.0 x 10(-12) M. In contrast to existing methods based on the conformation change of redox-labeled oligonucleotides, the proposed strategy offers several substantial advantages: first, the background peak current is eliminated as the ferrocene (Fc)-tagged oligonucleotide probe is specifically ligated to capture DNA; second, a "signal-on" mechanism makes the current intensity increase with increasing target DNA concentration; third, improved current signal is obtained due to the formation of the hairpin structure of ligation products. Additionally, the present system exhibits excellent capability to discriminate mutant target sequences from fully complementary target sequences.

  17. Diffusion and drive-point sampling to detect ordnance-related compounds in shallow ground water beneath Snake Pond, Cape Cod, Massachusetts, 2001-02

    USGS Publications Warehouse

    LeBlanc, Denis R.

    2003-01-01

    Diffusion samplers and temporary drive points were used to test for ordnance-related compounds in ground water discharging to Snake Pond near Camp Edwards at the Massachusetts Military Reservation, Cape Cod, MA. The contamination resulted from artillery use and weapons testing at various ranges upgradient of the pond.The diffusion samplers were constructed with a high-grade cellulose membrane that allowed diffusion of explosive compounds, such as RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine) and HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), into deionized water inside the samplers. Laboratory tests confirmed that the cellulose membrane was permeable to RDX and HMX. One transect of 22 diffusion samplers was installed and retrieved in August-September 2001, and 12 transects with a total of 108 samplers were installed and retrieved in September-October 2001. The diffusion samplers were buried about 0.5 feet into the pond-bottom sediments by scuba divers and allowed to equilibrate with the ground water beneath the pond bottom for 13 to 27 days before retrieval. Water samples were collected from temporary well points driven about 2-4 feet into the pond bottom at 21 sites in December 2001 and March 2002 for analysis of explosives and perchlorate to confirm the diffusion-sampling results. The water samples from the diffusion samplers exhibited numerous chromatographic peaks, but evaluation of the photo-diode-array spectra indicated that most of the peaks did not represent the target compounds. The peaks probably are associated with natural organic compounds present in the soft, organically enriched pond-bottom sediments. The presence of four explosive compounds at five widely spaced sites was confirmed by the photo-diode-array analysis, but the compounds are not generally found in contaminated ground water near the ranges. No explosives were detected in water samples obtained from the drive points. Perchlorate was detected at less than 1 microgram per liter in

  18. Detection of Group A Streptococcus from Pharyngeal Swab Samples by Bacterial Culture Is Challenged by a Novel mariPOC Point-of-Care Test

    PubMed Central

    Koskinen, Janne O.; Brandt, Annika; Muotiala, Anna; Liukko, Viivi; Soittu, Sari; Meriluoto, Siiri; Vesalainen, Marika; Huovinen, Pentti; Irjala, Kerttu

    2015-01-01

    mariPOC is a novel point-of-care test system for rapid detection of respiratory tract infections. We compared the performance of the mariPOC test to that of bacterial culture for detecting group A streptococcus (GAS) in 219 pharyngitis patients (ages 1–64 years) and 109 healthy asymptomatic controls (ages 19–69 years). In addition, 42 patient samples were analyzed by quantitative PCR (qPCR). Of the 219 pharyngeal patient samples, 32 were positive in a GAS bacterial culture (prevalence 15%) and 65 (30%) in the mariPOC test. The amount of GAS in samples reported positive by the mariPOC test and negative by culture was, on average, 10-fold less than that of those positive in both methods. This indicated that the negative results in bacterial cultures were due to lower sensitivity. The qPCR results were positive and in line with the mariPOC results in 43% of the discordant samples studied. Two GAS culture-positive samples were negative by the mariPOC test. The prevalences of GAS in the control subjects were 2% and 6% by culture and mariPOC results, respectively. We conclude that the mariPOC antigen detection test is more sensitive than the conventional bacterial culture for the detection of GAS among symptomatic pharyngitis patients. The higher prevalence of GAS by the mariPOC test among symptomatic patients was probably not due to carriership, since among the control patients, the difference in the prevalence of GAS by the mariPOC test and culture was not nearly as high, 15% versus 4%, respectively. Clinical trials are needed to show the clinical importance of our findings. PMID:25903570

  19. Influence of contact points on the performance of caries detection methods in approximal surfaces of primary molars: an in vivo study.

    PubMed

    Ribeiro, Apoena A; Purger, Flávia; Rodrigues, Jonas A; Oliveira, Patrícia R A; Lussi, Adrian; Monteiro, Antonio Henrique; Alves, Haimon D L; Assis, Joaquim T; Vasconcellos, Adalberto B

    2015-01-01

    This in vivo study aimed to evaluate the influence of contact points on the approximal caries detection in primary molars, by comparing the performance of the DIAGNOdent pen and visual-tactile examination after tooth separation to bitewing radiography (BW). A total of 112 children were examined and 33 children were selected. In three periods (a, b, and c), 209 approximal surfaces were examined: (a) examiner 1 performed visual-tactile examination using the Nyvad criteria (EX1); examiner 2 used DIAGNOdent pen (LF1) and took BW; (b) 1 week later, after tooth separation, examiner 1 performed the second visual-tactile examination (EX2) and examiner 2 used DIAGNOdent again (LF2); (c) after tooth exfoliation, surfaces were directly examined using DIAGNOdent (LF3). Teeth were examined by computed microtomography as a reference standard. Analyses were based on diagnostic thresholds: D1: D 0 = health, D 1 –D 4 = disease; D2: D 0 , D 1 = health, D 2 –D 4 = disease; D3: D 0 –D 2 = health, D 3 , D 4 = disease. At D1, the highest sensitivity/specificity were observed for EX1 (1.00)/LF3 (0.68), respectively. At D2, the highest sensitivity/ specificity were observed for LF3 (0.69)/BW (1.00), respectively. At D3, the highest sensitivity/specificity were observed for LF3 (0.78)/EX1, EX2 and BW (1.00). EX1 showed higher accuracy values than LF1, and EX2 showed similar values to LF2. We concluded that the visual-tactile examination showed better results in detecting sound surfaces and approximal caries lesions without tooth separation. However, the effectiveness of approximal caries lesion detection of both methods was increased by the absence of contact points. Therefore, regardless of the method of detection, orthodontic separating elastics should be used as a complementary tool for the diagnosis of approximal noncavitated lesions in primary molars.

  20. Web Accessibility and Guidelines

    NASA Astrophysics Data System (ADS)

    Harper, Simon; Yesilada, Yeliz

    Access to, and movement around, complex online environments, of which the World Wide Web (Web) is the most popular example, has long been considered an important and major issue in the Web design and usability field. The commonly used slang phrase ‘surfing the Web’ implies rapid and free access, pointing to its importance among designers and users alike. It has also been long established that this potentially complex and difficult access is further complicated, and becomes neither rapid nor free, if the user is disabled. There are millions of people who have disabilities that affect their use of the Web. Web accessibility aims to help these people to perceive, understand, navigate, and interact with, as well as contribute to, the Web, and thereby the society in general. This accessibility is, in part, facilitated by the Web Content Accessibility Guidelines (WCAG) currently moving from version one to two. These guidelines are intended to encourage designers to make sure their sites conform to specifications, and in that conformance enable the assistive technologies of disabled users to better interact with the page content. In this way, it was hoped that accessibility could be supported. While this is in part true, guidelines do not solve all problems and the new WCAG version two guidelines are surrounded by controversy and intrigue. This chapter aims to establish the published literature related to Web accessibility and Web accessibility guidelines, and discuss limitations of the current guidelines and future directions.

  1. Determination of acid/base dissociation constants based on a rapid detection of the half equivalence point by feedback-based flow ratiometry.

    PubMed

    Tanaka, Hideji; Tachibana, Takahiro

    2004-06-01

    Acid dissociation constants (Ka) were determined through the rapid detection of the half equivalence point (EP1/2) based on a feedback-based flow ratiometry. A titrand, delivered at a constant flow rate, was merged with a titrant, whose flow rate was varied in response to a control voltage (Vc) from a controller. Downstream, the pH of the mixed solution was monitored. Initially, Vc was increased linearly. At the instance that the detector sensed EP1/2, the ramp direction of Vc changed downward. When EP1/2 was sensed again, Vc was increased again. This series of process was repeated automatically. The pH at EP1/2 was regarded as being pKa of the analyte after an activity correction. Satisfactory results were obtained for different acids in various matrices with good precision (RSD approximately 3%) at a throughput rate of 56 s/determination.

  2. Detection of spatial fluctuations of non-point source fecal pollution in coral reef surrounding waters in southwestern Puerto Rico using PCR-based assays.

    PubMed

    Bonkosky, M; Hernández-Delgado, E A; Sandoz, B; Robledo, I E; Norat-Ramírez, J; Mattei, H

    2009-01-01

    Human fecal contamination of coral reefs is a major cause of concern. Conventional methods used to monitor microbial water quality cannot be used to discriminate between different fecal pollution sources. Fecal coliforms, enterococci, and human-specific Bacteroides (HF183, HF134), general Bacteroides-Prevotella (GB32), and Clostridium coccoides group (CP) 16S rDNA PCR assays were used to test for the presence of non-point source fecal contamination across the southwestern Puerto Rico shelf. Inshore waters were highly turbid, consistently receiving fecal pollution from variable sources, and showing the highest frequency of positive molecular marker signals. Signals were also detected at offshore waters in compliance with existing microbiological quality regulations. Phylogenetic analysis showed that most isolates were of human fecal origin. The geographic extent of non-point source fecal pollution was large and impacted extensive coral reef systems. This could have deleterious long-term impacts on public health, local fisheries and in tourism potential if not adequately addressed.

  3. Validation of Rapid Point-of-Care (POC) Tests for Detection of Hepatitis B Surface Antigen in Field and Laboratory Settings in the Gambia, Western Africa

    PubMed Central

    Njai, Harr Freeya; Shimakawa, Yusuke; Sanneh, Bakary; Ferguson, Lynne; Ndow, Gibril; Mendy, Maimuna; Sow, Amina; Lo, Gora; Toure-Kane, Coumba; Tanaka, Junko; Taal, Makie; D'alessandro, Umberto; Njie, Ramou; Thursz, Mark

    2015-01-01

    Hepatitis B virus (HBV) infection is a leading cause of death in sub-Saharan Africa (SSA). Point-of-care tests for hepatitis B surface antigen (HBsAg) could be an ideal tool for a large-scale HBV screening/treatment program in SSA. Using data from the PROLIFICA (Prevention of Liver Fibrosis and Cancer in Africa) program, we conducted a cross-sectional study to assess the diagnostic accuracy of three point-of-care tests (Determine, Vikia, and Espline) for the detection of HBsAg in the field or a laboratory setting in the Gambia. In the field, we used finger-prick whole blood for the Determine and Vikia tests and dried blood spots for the reference standard test (AxSYM HBsAg enzyme-linked immunosorbent assay [ELISA]). In the laboratory we used serum for the Determine, Espline, and reference test (Architect chemiluminescent microparticle immunoassay). Of 773 participants recruited at the community and 227 known chronic HBV carriers (1,000 subjects in total), 293 were positive for HBsAg. The sensitivity and specificity of the Determine test were 88.5% and 100% in the field and 95.3% and 93.3% in the laboratory setting, respectively. The sensitivity and specificity were 90.0% and 99.8% for the Vikia test (in the field) and 93.9% and 94.7% for the Espline test (in the laboratory). There was no evidence that one kit was better than another. Most of the patients with false-negative results (18/19) were classified as inactive chronic carriers. In summary, the three point-of-care tests had acceptable ranges of diagnostic accuracy. These tests may represent accurate, rapid, and inexpensive alternatives to serology testing for the screening of HBV infection at field level in SSA. PMID:25631805

  4. Magnetic bead fluorescent immunoassay for the rapid detection of the novel inflammation marker YKL40 at the point-of-care.

    PubMed

    Schmalenberg, Michael; Beaudoin, Christopher; Bulst, Ludwig; Steubl, Dominik; Luppa, Peter B

    2015-12-01

    Pneumonia is one of the leading causes of death worldwide.We present a magnetic bead fluorescent sandwich immunoassay that allows rapid serum measurement of the novel inflammation marker YKL40 (CHI3L1) at the point of care (POC) that could aid pneumonia diagnosis. The magnetic beads serve as the solid phase for separation of YKL40 from serum. The readout is performed using a small and robust fluorescence reader,which detects the turnover of a fluorescent substrate. The assay procedure, from sample addition to data retrieval, consists of three steps and is performed in less than 20 min. The presented assay has a linear range from 3 to 111 ng/mL, with a limit of detection of 2.9 ng/mL. The average recoveries were found between 101 and 111%. The developed method was applied in sera from healthy subjects (n= 14; c(YKL40)= 50 ± 49 ng/mL) and from pneumonia patients (n = 14; c(YKL40) = 333.6 ± 225 ng/mL). The elevated YKL40 concentrations in pneumonia-diseased patients are in good agreement with previously published data. The POC-ready device provides a simple immunoassay that could help to optimize pneumonia inflammation diagnostics in low-resource settings. PMID:26434383

  5. Defectless Monolithic Low-k/Cu Interconnects Produced by Chemically Controlled Chemical Mechanical Polishing Process with In situ End-Point-Detection Technique

    NASA Astrophysics Data System (ADS)

    Ueki, Makoto; Onodera, Takahiro; Ishikawa, Akira; Hoshino, Susumu; Hayashi, Yoshihiro

    2009-04-01

    Defectless monolithic low-k/Cu interconnects have been obtained for low-power LSIs by a chemically controlled local chemical mechanical polishing (CMP) process to remove a Cu/TaN barrier on hydrophobic SiOCH low-k films. In the first step, Cu-CMP, a unique end-point-detection (EDP) method is implemented to detect a very thin Cu layer (˜100 nm) that remains on the TaN barrier by in situ white-light interferometry, which is implemented in the local CMP apparatus where the wafers undergoing polishing are oriented face-up. In the second step, TaN-CMP, a SiO2 hard-mask (HM) layer on the low-k film is selectively removed to reduce the nonuniformity of the Cu line thickness, and accordingly, those of the resistance and capacitance. Here, a CMP slurry with an oxidizer is used to change the low-k surface from a hydrophobic condition to a hydrophilic condition, improving wettability and reducing the number of scratches and abrasive particles. In the post-CMP cleaning, an alkaline rinse solution with an oxidation-reduction potential (ORP) of less than -0.5 V vs a normal hydrogen electrode (NHE) produces a clean low-k surface resulting in monolithic low-k/Cu interconnects with excellent dielectric properties comparable to those of SiO2/Cu interconnects.

  6. A novel μ-fluidic whole blood coagulation assay based on Rayleigh surface-acoustic waves as a point-of-care method to detect anticoagulants

    PubMed Central

    Meyer dos Santos, Sascha; Zorn, Anita; Guttenberg, Zeno; Picard-Willems, Bettina; Kläffling, Christina; Nelson, Karen; Klinkhardt, Ute; Harder, Sebastian

    2013-01-01

    A universal coagulation test that reliably detects prolonged coagulation time in patients, irrespective of the anticoagulant administered, has not been available to date. An easily miniaturised, novel μ-fluidic universal coagulation test employing surface acoustic waves (SAW) is presented here. SAW was employed to instantly mix and recalcify 6 μl citrated whole blood and image correlation analysis was used to quantify clot formation kinetics. The detection of clinically relevant anticoagulant dosing with old anticoagulants (unfractionated heparin, argatroban) and new anticoagulants (dabigatran, rivaroxaban) has been tested and compared to standard plasma coagulation assays. The applicability of this novel method has been confirmed in a small patient population. Coagulation was dose-proportionally prolonged with heparin, argatroban, dabigatran, and rivaroxaban, comparable to standard tests. Aspirin and clopidogrel did not interfere with the SAW-induced clotting time (SAW-CT), whereas the strong GPIIb/IIIa-inhibitor abciximab did interfere. Preliminary clinical data prove the suitability of the SAW-CT in patients being treated with warfarin, rivaroxaban, or dabigatran. The system principally allows assessment of whole blood coagulation in humans in a point-of-care setting. This method could be used in stroke units, emergency vehicles, general and intensive care wards, as well as for laboratory and home testing of coagulation. PMID:24404078

  7. Enhanced detection of DNA sequences using end-point PCR amplification and online gel electrophoresis (GE)-ICP-MS: determination of gene copy number variations.

    PubMed

    González, T Iglesias; Espina, M; Sierra, L M; Bettmer, J; Blanco-González, E; Montes-Bayón, M; Sanz-Medel, A

    2014-11-18

    The design and evaluation of analytical methods that permit quantitative analysis of specific DNA sequences is exponentially increasing. For this purpose, highly sensitive methodologies usually based on labeling protocols with fluorescent dyes or nanoparticles are often explored. Here, the possibility of label-free signal amplification using end-point polymerase chain reaction (PCR) are exploited using on-column agarose gel electrophoresis as separation and inductively coupled plasma-mass spectrometry (ICP-MS) for the detection of phosphorus in amplified DNA sequences. The calibration of the separation system with a DNA ladder permits direct estimation of the size of the amplified gene fragment after PCR. With this knowledge, and considering the compound-independent quantification capabilities exhibited by ICP-MS for phosphorus (it is only dependent on the number of P atoms per molecule), the correlation of the P-peak area of the amplified gene fragment, with respect to the gene copy numbers (in the starting DNA), is then established. Such a relationship would permit the determination of copy number variations (CNVs) in genomic DNA using ICP-MS measurements. The method detection limit, in terms of the required amount of starting DNA, is ∼6 ng (or 1000 cells if 100% extraction efficiency is expected). The suitability of the proposed label-free amplification strategy is applied to CNVs monitoring in cells exposed to a chemical agent capable of deletion induction, such as cisplatin. PMID:25312744

  8. Web Accessibility and Accessibility Instruction

    ERIC Educational Resources Information Center

    Green, Ravonne A.; Huprich, Julia

    2009-01-01

    Section 508 of the Americans with Disabilities Act (ADA) mandates that programs and services be accessible to people with disabilities. While schools of library and information science (SLIS*) and university libraries should model accessible Web sites, this may not be the case. This article examines previous studies about the Web accessibility of…

  9. A multiplexable, microfluidic platform for the rapid quantitation of a biomarker panel for early ovarian cancer detection at the point-of-care

    PubMed Central

    Shadfan, Basil H.; Simmons, Archana R.; Simmons, Glennon W.; Ho, Andy; Wong, Jorge; Lu, Karen H.; Bast, Robert C.; McDevitt, John T.

    2015-01-01

    Point-of-care (POC) diagnostic platforms have the potential to enable low-cost, large-scale screening. As no single biomarker is shed by all ovarian cancers, multiplexed biomarker panels promise improved sensitivity and specificity to address the unmet need for early detection of ovarian cancer. We have configured the programmable bio-nano-chip (p-BNC) - a multiplexable, microfluidic, modular platform - to quantify a novel multimarker panel comprising CA125, HE4, MMP-7 and CA72-4. The p-BNC is a bead-based immunoanalyzer system with a credit-card-sized footprint that integrates automated sample metering, bubble and debris removal, reagent storage and waste disposal, permitting POC analysis. Multiplexed p-BNC immunoassays demonstrated high specificity, low cross-reactivity, low limits of detection suitable for early detection, and a short analysis time of 43 minutes. Day-to-day variability, a critical factor for longitudinally monitoring biomarkers, ranged between 5.4–10.5%, well below the biological variation for all four markers. Biomarker concentrations for 31 late-stage sera correlated well (R2 = 0.71 to 0.93 for various biomarkers) with values obtained on the Luminex® platform. In a 31 patient cohort encompassing early- and late-stage ovarian cancers along with benign and healthy controls, the multiplexed p-BNC panel was able to distinguish cases from controls with 68.7% sensitivity at 80% specificity. Utility for longitudinal biomarker monitoring was demonstrated with pre-diagnostic sera from 2 cases and 4 controls. Taken together, the p-BNC shows strong promise as a diagnostic tool for large-scale screening that takes advantage of faster results and lower costs while leveraging possible improvement in sensitivity and specificity from biomarker panels. PMID:25388014

  10. Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

    SciTech Connect

    Ohmacht, Martin

    2014-09-09

    In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

  11. Point Cloud Server (pcs) : Point Clouds In-Base Management and Processing

    NASA Astrophysics Data System (ADS)

    Cura, R.; Perret, J.; Paparoditis, N.

    2015-08-01

    In addition to the traditional Geographic Information System (GIS) data such as images and vectors, point cloud data has become more available. It is appreciated for its precision and true three-Dimensional (3D) nature. However, managing the point cloud can be difficult due to scaling problems and specificities of this data type. Several methods exist but are usually fairly specialised and solve only one aspect of the management problem. In this work, we propose a complete and efficient point cloud management system based on a database server that works on groups of points rather than individual points. This system is specifically designed to solve all the needs of point cloud users: fast loading, compressed storage, powerful filtering, easy data access and exporting, and integrated processing. Moreover, the system fully integrates metadata (like sensor position) and can conjointly use point clouds with images, vectors, and other point clouds. The system also offers in-base processing for easy prototyping and parallel processing and can scale well. Lastly, the system is built on open source technologies; therefore it can be easily extended and customised. We test the system will several billion points of point clouds from Lidar (aerial and terrestrial ) and stereo-vision. We demonstrate ~ 400 million pts/h loading speed, user-transparent greater than 2 to 4:1 compression ratio, filtering in the approximately 50 ms range, and output of about a million pts/s, along with classical processing, such as object detection.

  12. Significant decadal channel change 58-67 years post-dam accounting for uncertainty in topographic change detection between contour maps and point cloud models

    NASA Astrophysics Data System (ADS)

    Carley, Jennifer K.; Pasternack, Gregory B.; Wyrick, Joshua R.; Barker, Jesse R.; Bratovich, Paul M.; Massa, Duane A.; Reedy, Gary D.; Johnson, Thomas R.

    2012-12-01

    Construction of digital elevation models (DEMs) and the subtraction of DEMs between different points in time as a method to determine temporal patterns of scour and fill is a highly valuable procedure emerging in geomorphology. These DEMs of Differences (DoDs) must be assessed for error in order to distinguish actual topographic change from uncertainty and surface error. Current methods include: (1) uniformly excluding all values that fall below a minimum threshold; (2) using a spatially variable approach such as the construction of minimum Level of Detection (LoD) grids; or (3) the creation of a fuzzy inference system. Although spatially variable methods for determining error have been more accurate in excluding noise without discarding large amounts of meaningful data, a challenge remains in performing DoDs against preexisting contour-based maps for which no original point data are available. The goals of this study were to (1) develop a method that overcomes the unknown point density of contour (and other historical) data sets and allows for some assessment of DoD uncertainty on the basis of information on topographic variability, (2) perform comprehensive uncertainty analysis testing to understand the opportunities and constraints associated with this new method, and (3) report and interpret the overall pattern and volume of decadal topographic change for a regulated river 67 years post-dam in light of alternate conjectured mechanisms of post-dam longitudinal profile adjustment. The key feature of the new approach is the introduction of a high-density artificial point grid that samples the topographic variability evident in the available historical data set. The testbed used to develop and assess this new DoD method was the ~ 37.5-km lower Yuba River, California. Historical data consisted of 0.6-m contours from a 1999 survey, while a more detailed point cloud was available for the most recent survey in 2006-2008. To evaluate uncertainty in the method, this

  13. Roll-to-roll, shrink-induced superhydrophobic surfaces for antibacterial applications, enhanced point-of-care detection, and blood anticoagulation

    NASA Astrophysics Data System (ADS)

    Nokes, Jolie McLane

    Superhydrophobic (SH) surfaces are desirable because of their unique anti-wetting behavior. Fluid prefers to bead up (contact angle >150°) and roll off (contact angle hysteresis <10°) a SH surface because micro- and nanostructure features trap air pockets. Fluid only adheres to the peaks of the structures, causing minimal adhesion to the surface. Here, shrink-induced SH plastics are fabricated for a plethora of applications, including antibacterial applications, enhanced point-of-care (POC) detection, and reduced blood coagulation. Additionally, these purely structural SH surfaces are achieved in a roll-to-roll (R2R) platform for scalable manufacturing. Because their self-cleaning and water resistant properties, structurally modified SH surfaces prohibit bacterial growth and obviate bacterial chemical resistance. Antibacterial properties are demonstrated in a variety of SH plastics by preventing gram-negative Escherichia coli (E. coli) bacterial growth >150x compared to flat when fluid is rinsed and >20x without rinsing. Therefore, a robust and stable means to prevent bacteria growth is possible. Next, protein in urine is detected using a simple colorimetric output by evaporating droplets on a SH surface. Contrary to evaporation on a flat surface, evaporation on a SH surface allows fluid to dramatically concentrate because the weak adhesion constantly decreases the footprint area. On a SH surface, molecules in solution are confined to a footprint area 8.5x smaller than the original. By concentrating molecules, greater than 160x improvements in detection sensitivity are achieved compared to controls. Utility is demonstrated by detecting protein in urine in the pre-eclampsia range (150-300microgmL -1) for pregnant women. Further, SH surfaces repel bodily fluids including blood, urine, and saliva. Importantly, the surfaces minimize blood adhesion, leading to reduced blood coagulation without the need for anticoagulants. SH surfaces have >4200x and >28x reduction of

  14. MountPointAttributes

    2001-06-16

    MountPointAttributes is a software component that provides client code with a technique to raise the local namespace of a file to a global namespace. Its abstractions and mechanisms allow the client code to gather global properties of a file and to use them in devising an effective storage access strategy on this file.

  15. EcoTipping Points

    ERIC Educational Resources Information Center

    Marten, Gerald G.; Matthews, Catherine E.

    2009-01-01

    Contrary to what we often hear and teach, there is good news to be found on the environmental front. Environmental success stories show us not only that sustainability is possible, but also how people have made it happen. We can make these stories and their lessons accessible to students with help from the EcoTipping Points Project, which has…

  16. The Lagrange Points

    ERIC Educational Resources Information Center

    Lovell, M.S.

    2007-01-01

    This paper presents a derivation of all five Lagrange points by methods accessible to sixth-form students, and provides a further opportunity to match Newtonian gravity with centripetal force. The predictive powers of good scientific theories are also discussed with regard to the philosophy of science. Methods for calculating the positions of the…

  17. Resistance to the Novel Fungicide Pyrimorph in Phytophthora capsici: Risk Assessment and Detection of Point Mutations in CesA3 That Confer Resistance

    PubMed Central

    Pang, Zhili; Shao, Jingpeng; Chen, Lei; Lu, Xiaohong; Hu, Jian; Qin, Zhaohai; Liu, Xili

    2013-01-01

    Pyrimorph is a novel fungicide with high activity against the plant pathogen Phytophthora capsici. We investigated the risk that P. capsici can develop resistance to pyrimorph. The baseline sensitivities of 226 P. capsici isolates, tested by mycelial growth inhibition, showed a unimodal distribution with a mean EC50 value of 1.4261 (±0.4002) µg/ml. Twelve pyrimorph-resistant mutants were obtained by repeated exposure to pyrimorph in vitro with a frequency of approximately 1×10−4. The resistance factors of the mutants ranged from 10.67 to 56.02. Pyrimorph resistance of the mutants was stable after 10 transfers on pyrimorph-free medium. Fitness in sporulation, cystospore germination, and pathogenicity in the pyrimorph-resistant mutants was similar to or less than that in the parental wild-type isolates. On detached pepper leaves and pepper plants treated with the recommended maximum dose of pyrimorph, however, virulence was greater for mutants with a high level of pyrimorph resistance than for the wild type. The results suggest that the risk of P. capsici developing resistance to pyrimorph is low to moderate. Among mutants with a high level of pyrimorph resistance, EC50 values for pyrimorph and CAA fungicides flumorph, dimethomorph, and mandipropamid were positively correlated. This indicated that point mutations in cellulose synthase 3 (CesA3) may confer resistance to pyrimorph. Comparison of CesA3 in isolates with a high level of pyrimorph resistance and parental isolates showed that an amino acid change from glutamine to lysine at position 1077 resulted in stable, high resistance in the mutants. Based on the point mutations, an allele-specific PCR method was developed to detect pyrimorph resistance in P. capsici populations. PMID:23431382

  18. Point-of-care detection of lipoarabinomannan (LAM) in urine for diagnosis of HIV-associated tuberculosis: a state of the art review

    PubMed Central

    2012-01-01

    Detection of Mycobacterium tuberculosis antigens in urine is attractive as a potential means of diagnosing tuberculosis (TB) regardless of the anatomical site of disease. The most promising candidate antigen is the cell wall lipopolysaccharide antigen lipoarabinomannan (LAM), which has been used to develop commercially available enzyme-linked immunosorbent assays. Although highly variable diagnostic accuracy has been observed in different clinical populations, it is now clear that this assay has useful sensitivity for diagnosis of HIV-associated TB in patients with advanced immunodeficiency and low CD4 cell counts. Thus, this assay is particularly useful when selectively used among patients enrolling in antiretroviral treatment services or in HIV-infected patients requiring admission to hospital medical wards. These are the very patients who have the highest mortality risk and who stand to gain the most from rapid diagnosis, permitting immediate initiation of TB treatment. A recently developed low-cost, lateral-flow (urine ‘dip-stick’) format of the assay provides a result within 30 minutes and is potentially a major step forward as it can be used at the point-of-care, making the possibility of immediate diagnosis and treatment a reality. This paper discusses the likely utility of this point-of-care assay and how it might best be used in combination with other diagnostic assays for TB. The many further research studies that are needed on this assay are described. Consideration is particularly given to potential reasons for the variable specificity observed in existing field evaluations of LAM ELISAs. Whether this might be related to the assay itself or to the challenges associated with study design is discussed. PMID:22536883

  19. Resistance to the novel fungicide pyrimorph in Phytophthora capsici: risk assessment and detection of point mutations in CesA3 that confer resistance.

    PubMed

    Pang, Zhili; Shao, Jingpeng; Chen, Lei; Lu, Xiaohong; Hu, Jian; Qin, Zhaohai; Liu, Xili

    2013-01-01

    Pyrimorph is a novel fungicide with high activity against the plant pathogen Phytophthora capsici. We investigated the risk that P. capsici can develop resistance to pyrimorph. The baseline sensitivities of 226 P. capsici isolates, tested by mycelial growth inhibition, showed a unimodal distribution with a mean EC(50) value of 1.4261 (± 0.4002) µg/ml. Twelve pyrimorph-resistant mutants were obtained by repeated exposure to pyrimorph in vitro with a frequency of approximately 1 × 10(-4). The resistance factors of the mutants ranged from 10.67 to 56.02. Pyrimorph resistance of the mutants was stable after 10 transfers on pyrimorph-free medium. Fitness in sporulation, cystospore germination, and pathogenicity in the pyrimorph-resistant mutants was similar to or less than that in the parental wild-type isolates. On detached pepper leaves and pepper plants treated with the recommended maximum dose of pyrimorph, however, virulence was greater for mutants with a high level of pyrimorph resistance than for the wild type. The results suggest that the risk of P. capsici developing resistance to pyrimorph is low to moderate. Among mutants with a high level of pyrimorph resistance, EC(50) values for pyrimorph and CAA fungicides flumorph, dimethomorph, and mandipropamid were positively correlated. This indicated that point mutations in cellulose synthase 3 (CesA3) may confer resistance to pyrimorph. Comparison of CesA3 in isolates with a high level of pyrimorph resistance and parental isolates showed that an amino acid change from glutamine to lysine at position 1077 resulted in stable, high resistance in the mutants. Based on the point mutations, an allele-specific PCR method was developed to detect pyrimorph resistance in P. capsici populations.

  20. A novel asymmetric-loop molecular beacon-based two-phase hybridization assay for accurate and high-throughput detection of multiple drug resistance-conferring point mutations in Mycobacterium tuberculosis.

    PubMed

    Chen, Qinghai; Wu, Nan; Xie, Meng; Zhang, Bo; Chen, Ming; Li, Jianjun; Zhuo, Lisha; Kuang, Hong; Fu, Weiling

    2012-04-01

    The accurate and high-throughput detection of drug resistance-related multiple point mutations remains a challenge. Although the combination of molecular beacons with bio-immobilization technology, such as microarray, is promising, its application is difficult due to the ineffective immobilization of molecular beacons on the chip surface. Here, we propose a novel asymmetric-loop molecular beacon in which the loop consists of 2 parts. One is complementary to a target, while the other is complementary to an oligonucleotide probe immobilized on the chip surface. With this novel probe, a two-phase hybridization assay can be used for simultaneously detecting multiple point mutations. This assay will have advantages, such as easy probe availability, multiplex detection, low background, and high-efficiency hybridization, and may provide a new avenue for the immobilization of molecular beacons and high-throughput detection of point mutations.

  1. Prospective assessment of rapid diagnostic tests for the detection of antibodies to hepatitis C virus, a tool for improving access to care.

    PubMed

    Chevaliez, S; Poiteau, L; Rosa, I; Soulier, A; Roudot-Thoraval, F; Laperche, S; Hézode, C; Pawlotsky, J-M

    2016-05-01

    Large-scale hepatitis C screening is required to prevent further spread of the infection, improve access to care in the context of new hepatitis C virus (HCV) drug regimens without interferon-alpha and subsequently reduce the risk of long-term complications of chronic liver disease. Rapid diagnostic tests (RDTs) represent an attractive alternative to enzyme immunoassay using blood from venepuncture. The aim of the present study was to prospectively assess the clinical performance of CE-marked RDTs detecting anti-HCV antibodies in fingerstick capillary whole blood and/or oral fluid. A total of 513 individuals, including 318 patients with chronic HCV infection, 25 patients with resolved HCV infection and 170 HCV-seronegative individuals, were prospectively enrolled. The specificity of RDTs with fingerstick whole blood varied from 98.8% to 100%. The clinical sensitivity was high for the OraQuick(®) and Toyo(®) tests (99.4% and 95.8%, respectively), but low for the Labmen(®) test (63.1%). The specificity and clinical sensitivity in crevicular fluid were both satisfactory for the OraQuick(®) test (100% and 97.6%, respectively). HCV antibody RDTs were easy and rapid to perform in the context of patient care. They were highly specific. Both the OraQuick(®) and Toyo(®) tests reached the expected level of performance for wide-scale use, with a performance advantage for the OraQuick(®) HCV test. RDTs appear to be a promising new tool for wide-scale screening of HCV infection in high-risk to medium-risk populations. Hence, careful assessment of the performance of HCV RDTs must be recommended before they can be implemented in clinical practice. PMID:26806260

  2. Access Denied

    ERIC Educational Resources Information Center

    Villano, Matt

    2008-01-01

    Building access control (BAC)--a catchall phrase to describe the systems that control access to facilities across campus--has traditionally been handled with remarkably low-tech solutions: (1) manual locks; (2) electronic locks; and (3) ID cards with magnetic strips. Recent improvements have included smart cards and keyless solutions that make use…

  3. Open Access

    ERIC Educational Resources Information Center

    Suber, Peter

    2012-01-01

    The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder…

  4. Resistance Assessment for Oxathiapiprolin in Phytophthora capsici and the Detection of a Point Mutation (G769W) in PcORP1 that Confers Resistance

    PubMed Central

    Miao, Jianqiang; Cai, Meng; Dong, Xue; Liu, Li; Lin, Dong; Zhang, Can; Pang, Zhili; Liu, Xili

    2016-01-01

    The potential for oxathiapiprolin resistance in Phytophthora capsici was evaluated. The baseline sensitivities of 175 isolates to oxathiapiprolin were initially determinated and found to conform to a unimodal curve with a mean EC50 value of 5.61 × 10-4 μg/ml. Twelve stable oxathiapiprolin-resistant mutants were generated by fungicide adaptation in two sensitive isolates, LP3 and HNJZ10. The fitness of the LP3-mutants was found to be similar to or better than that of the parental isolate LP3, while the HNJZ10-mutants were found to have lost the capacity to produce zoospores. Taken together these results suggest that the risk of P. capsici developing resistance to oxathiapiprolin is moderate. Comparison of the PcORP1 genes in the LP3-mutants and wild-type parental isolate, which encode the target protein of oxathiapiprolin, revealed that a heterozygous mutation caused the amino acid substitution G769W. Transformation and expression of the mutated PcORP1-769W allele in the sensitive wild-type isolate BYA5 confirmed that the mutation in PcORP1 was responsible for the observed oxathiapiprolin resistance. Finally diagnostic tests including As-PCR and CAPs were developed to detect the oxathiapiprolin resistance resulting from the G769W point mutation in field populations of P. capsici. PMID:27199944

  5. A multi-analyte biosensor for the simultaneous label-free detection of pathogens and biomarkers in point-of-need animal testing.

    PubMed

    Ewald, Melanie; Fechner, Peter; Gauglitz, Günter

    2015-05-01

    For the first time, a multi-analyte biosensor platform has been developed using the label-free 1-lambda-reflectometry technique. This platform is the first, which does not use imaging techniques, but is able to perform multi-analyte measurements. It is designed to be portable and cost-effective and therefore allows for point-of-need testing or on-site field-testing with possible applications in diagnostics. This work highlights the application possibilities of this platform in the field of animal testing, but is also relevant and transferable to human diagnostics. The performance of the platform has been evaluated using relevant reference systems like biomarker (C-reactive protein) and serology (anti-Salmonella antibodies) as well as a panel of real samples (animal sera). The comparison of the working range and limit of detection shows no loss of performance transferring the separate assays to the multi-analyte setup. Moreover, the new multi-analyte platform allows for discrimination between sera of animals infected with different Salmonella subtypes.

  6. Combined strategies for optimal detection of the contact point in AFM force-indentation curves obtained on thin samples and adherent cells.

    PubMed

    Gavara, Núria

    2016-01-01

    Atomic Force Microscopy (AFM) is a widely used tool to study cell mechanics. Current AFM setups perform high-throughput probing of living cells, generating large amounts of force-indentations curves that are subsequently analysed using a contact-mechanics model. Here we present several algorithms to detect the contact point in force-indentation curves, a crucial step to achieve fully-automated analysis of AFM-generated data. We quantify and rank the performance of our algorithms by analysing a thousand force-indentation curves obtained on thin soft homogeneous hydrogels, which mimic the stiffness and topographical profile of adherent cells. We take advantage of the fact that all the proposed algorithms are based on sequential search strategies, and show that a combination of them yields the most accurate and unbiased results. Finally, we also observe improved performance when force-indentation curves obtained on adherent cells are analysed using our combined strategy, as compared to the classical algorithm used in the majority of previous cell mechanics studies. PMID:26891762

  7. Combined strategies for optimal detection of the contact point in AFM force-indentation curves obtained on thin samples and adherent cells

    NASA Astrophysics Data System (ADS)

    Gavara, Núria

    2016-02-01

    Atomic Force Microscopy (AFM) is a widely used tool to study cell mechanics. Current AFM setups perform high-throughput probing of living cells, generating large amounts of force-indentations curves that are subsequently analysed using a contact-mechanics model. Here we present several algorithms to detect the contact point in force-indentation curves, a crucial step to achieve fully-automated analysis of AFM-generated data. We quantify and rank the performance of our algorithms by analysing a thousand force-indentation curves obtained on thin soft homogeneous hydrogels, which mimic the stiffness and topographical profile of adherent cells. We take advantage of the fact that all the proposed algorithms are based on sequential search strategies, and show that a combination of them yields the most accurate and unbiased results. Finally, we also observe improved performance when force-indentation curves obtained on adherent cells are analysed using our combined strategy, as compared to the classical algorithm used in the majority of previous cell mechanics studies.

  8. Detection of Delta9-tetrahydrocannabinol and amphetamine-type stimulants in oral fluid using the Rapid Stat point-of-collection drug-testing device.

    PubMed

    Röhrich, J; Zörntlein, S; Becker, J; Urban, R

    2010-04-01

    The Rapid Stat assay, a point-of-collection drug-testing device for detection of amphetamines, cannabinoids, cocaine, opiates, methadone, and benzodiazepines in oral fluid, was evaluated for cannabis and amphetamine-type stimulants. The Rapid Stat tests (n = 134) were applied by police officers in routine traffic checks. Oral fluid and blood samples were analyzed using gas chromatography-mass spectrometry (GC-MS) for Delta(9)-tetrahydrocannabinol, amphetamine, methamphetamine, methylenedioxymethamphetamine, methylenedioxyethylamphetamine, and methylenedioxyamphetamine. The comparison of GC-MS analysis of oral fluid with the Rapid Stat results for cannabis showed a sensitivity of 85%, a specificity of 87%, and a total confirmation rate of 87%. When compared with serum, the sensitivity of the cannabis assay decreased to 71%, the specificity to 60%, and the total confirmation rate to 66%. These findings were possibly caused by an incorrect reading of the THC test results. Comparison of the Rapid Stat amphetamine assay with GC-MS in oral fluid showed a sensitivity of 94%, a specificity of 97%, and a total confirmation rate of 97%. Compared with serum, a sensitivity of 100%, a specificity of 90%, and a total confirmation rate of 92% was found. The amphetamine assay must, therefore, be regarded as satisfactory.

  9. Evaluation of point-of-contact circulating cathodic antigen assays for the detection of Schistosoma mansoni infection in low-, moderate-, and high-prevalence schools in western Kenya.

    PubMed

    Foo, Karen T; Blackstock, Anna J; Ochola, Elizabeth A; Matete, Daniel O; Mwinzi, Pauline N M; Montgomery, Susan P; Karanja, Diana M S; Secor, W Evan

    2015-06-01

    We evaluated the performance of a point-of-contact circulating cathodic antigen assay (POC-CCA) to detect schistosome infections in primary school children (N = 1,801) living in areas with low, moderate, and high Schistosoma mansoni prevalence in western Kenya. The commercially available assay (CCA-1) and a second, experimental formulation (CCA-2) were compared against Kato-Katz stool examinations and an anti-schistosome enzyme-linked immunosorbent assay (ELISA). A latent class model based on the four tests was used to establish "true infection status" in three different zones based on their distance from Lake Victoria. As a screening tool for community treatment according to World Health Organization (WHO) guidelines, the Kato-Katz examination was in closest agreement with the latent class model, followed by the experimental CCA-2, soluble adult worm antigen preparation (SWAP) ELISA, and CCA-1, which had high sensitivity compared with the other tests but was consistently the least specific. Our experience suggests that POC-CCA tests offer a field-friendly alternative to Kato-Katz, but need further interpretation for appropriate field use. PMID:25870418

  10. Evaluation of point-of-contact circulating cathodic antigen assays for the detection of Schistosoma mansoni infection in low-, moderate-, and high-prevalence schools in western Kenya.

    PubMed

    Foo, Karen T; Blackstock, Anna J; Ochola, Elizabeth A; Matete, Daniel O; Mwinzi, Pauline N M; Montgomery, Susan P; Karanja, Diana M S; Secor, W Evan

    2015-06-01

    We evaluated the performance of a point-of-contact circulating cathodic antigen assay (POC-CCA) to detect schistosome infections in primary school children (N = 1,801) living in areas with low, moderate, and high Schistosoma mansoni prevalence in western Kenya. The commercially available assay (CCA-1) and a second, experimental formulation (CCA-2) were compared against Kato-Katz stool examinations and an anti-schistosome enzyme-linked immunosorbent assay (ELISA). A latent class model based on the four tests was used to establish "true infection status" in three different zones based on their distance from Lake Victoria. As a screening tool for community treatment according to World Health Organization (WHO) guidelines, the Kato-Katz examination was in closest agreement with the latent class model, followed by the experimental CCA-2, soluble adult worm antigen preparation (SWAP) ELISA, and CCA-1, which had high sensitivity compared with the other tests but was consistently the least specific. Our experience suggests that POC-CCA tests offer a field-friendly alternative to Kato-Katz, but need further interpretation for appropriate field use.

  11. One Hundred Twenty-One Dystrophin Point Mutations Detected from Stored DNA Samples by Combinatorial Denaturing High-Performance Liquid Chromatography

    PubMed Central

    Torella, Annalaura; Trimarco, Amelia; Del Vecchio Blanco, Francesca; Cuomo, Anna; Aurino, Stefania; Piluso, Giulio; Minetti, Carlo; Politano, Luisa; Nigro, Vincenzo

    2010-01-01

    Duchenne and Becker muscular dystrophies are caused by a large number of different mutations in the dystrophin gene. Outside of the deletion/duplication “hot spots,” small mutations occur at unpredictable positions. These account for about 15 to 20% of cases, with the major group being premature stop codons. When the affected male is deceased, carrier testing for family members and prenatal diagnosis become difficult and expensive. We tailored a cost-effective and reliable strategy to discover point mutations from stored DNA samples in the absence of a muscle biopsy. Samples were amplified in combinatorial pools and tested by denaturing high-performance liquid chromatography analysis. An anomalous elution profile belonging to two different pools univocally addressed the allelic variation to an unambiguous sample. Mutations were then detected by sequencing. We identified 121 mutations of 99 different types. Fifty-six patients show stop codons that represent the 46.3% of all cases. Three non-obvious single amino acid mutations were considered as causative. Our data support combinatorial denaturing high-performance liquid chromatography analysis as a clear-cut strategy for time and cost-effective identification of small mutations when only DNA is available. PMID:19959795

  12. Highly Sensitive and Novel Point-of-Care System, aQcare Chlamydia TRF Kit for Detecting Chlamydia trachomatis by Using Europium (Eu) (III) Chelated Nanoparticles

    PubMed Central

    Ham, Ji Yeon; Jung, Jaean; Hwang, Byung-Gap; Kim, Won-Jung; Kim, Young-Seop; Kim, Eun-Ju; Cho, Mi-Yeon; Hwang, Mi-Sun; Won, Dong Il

    2015-01-01

    Background The bacterium Chlamydia trachomatis is one of the leading causes of sexually transmitted diseases worldwide. Since no simple and effective tool exists to diagnose C. trachomatis infections, we evaluated a novel point-of-care (POC) test, aQcare Chlamydia TRF kit, which uses europium-chelated nanoparticles and a time-resolved fluorescence reader. Methods The test performance was evaluated by comparing the results obtained using the novel POC testing kit with those obtained using a nucleic acid amplification test (NAAT), using 114 NAAT-positive and 327 NAAT-negative samples. Results The cut-off value of the novel test was 20.8 with a detection limit of 0.27 ng/mL. No interference or cross-reactivity was observed. Diagnostic accuracy showed an overall sensitivity of 93.0% (106/114), specificity of 96.3% (315/327), positive predictive value (PPV) of 89.8% (106/118), and negative predictive value (NPV) of 97.5% (315/323). The sensitivity of the novel test was much higher than that of currently available POC tests. Furthermore, the relative ease and short turnaround time (30 min) of this assay enables C. trachomatis-infected individuals to be treated without a diagnostic delay. Conclusions This simple and novel test is a potential tool to screen a larger population, especially those in areas with limited resources. PMID:25553280

  13. Combined strategies for optimal detection of the contact point in AFM force-indentation curves obtained on thin samples and adherent cells

    PubMed Central

    Gavara, Núria

    2016-01-01

    Atomic Force Microscopy (AFM) is a widely used tool to study cell mechanics. Current AFM setups perform high-throughput probing of living cells, generating large amounts of force-indentations curves that are subsequently analysed using a contact-mechanics model. Here we present several algorithms to detect the contact point in force-indentation curves, a crucial step to achieve fully-automated analysis of AFM-generated data. We quantify and rank the performance of our algorithms by analysing a thousand force-indentation curves obtained on thin soft homogeneous hydrogels, which mimic the stiffness and topographical profile of adherent cells. We take advantage of the fact that all the proposed algorithms are based on sequential search strategies, and show that a combination of them yields the most accurate and unbiased results. Finally, we also observe improved performance when force-indentation curves obtained on adherent cells are analysed using our combined strategy, as compared to the classical algorithm used in the majority of previous cell mechanics studies. PMID:26891762

  14. Gaining Access.

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2000-01-01

    Discusses issues schools and universities have encountered in complying with the Americans with Disabilities Act (ADA) and making their facilities more accessible to the disabled. The ADA's vagueness and the architect's need for understanding the regulations is highlighted. (GR)

  15. Equal Access.

    ERIC Educational Resources Information Center

    De Patta, Joe

    2003-01-01

    Presents an interview with Stephen McCarthy, co-partner and president of Equal Access ADA Consulting Architects of San Diego, California, about designing schools to naturally integrate compliance with the Americans with Disabilities Act (ADA). (EV)

  16. Capital access.

    PubMed

    Towne, Jennifer

    2004-06-01

    To maintain their viability, hospitals are being compelled to invest in big capital projects such as information technology and renovation and construction. This gatefold examines the trends in credit and capital, and how they affect hospitals' access to money.

  17. Accuracy of point-of-care testing for circulatory cathodic antigen in the detection of schistosome infection: systematic review and meta-analysis

    PubMed Central

    Minton, Jonathan; Boamah, Daniel; Otchere, Joseph; Asmah, Richard H; Rodgers, Mark; Bosompem, Kwabena M; Eusebi, Paolo; De Vlas, Sake J

    2016-01-01

    Abstract Objective To assess the accuracy of point-of-care testing for circulatory cathodic antigen in the diagnosis of schistosome infection. Methods We searched MEDLINE, EMBASE, LILACS and other bibliographic databases for studies published until 30 September 2015 that described circulatory cathodic antigen testing compared against one to three Kato–Katz tests per subject – for Schistosoma mansoni – or the filtration of one 10-ml urine sample per subject – for S. haematobium. We extracted the numbers of true positives, false positives, true negatives and false negatives for the antigen testing and performed meta-analyses using a bivariate hierarchical regression model. Findings Twenty-six studies published between 1994 and 2014 met the inclusion criteria. In the detection of S. mansoni, a single antigen test gave a pooled sensitivity of 0.90 (95% confidence interval, CI: 0.84–0.94) and a pooled specificity of 0.56 (95% CI: 0.39–0.71; n = 7) when compared against a single Kato–Katz test. The corresponding values from comparisons with two to three Kato–Katz tests per subject were 0.85 (95% CI: 0.80–0.88) and 0.66 (95% CI: 0.53–0.76; n = 14), respectively. There appeared to be no advantage in using three antigen tests per subject instead of one. When compared against the results of urine filtration, antigen testing for S. haematobium showed poor sensitivity and poor specificity. The performance of antigen testing was better in areas of high endemicity than in settings with low endemicity. Conclusion Antigen testing may represent an effective tool for monitoring programmes for the control of S. mansoni. PMID:27429491

  18. Hemodialysis access - self care

    MedlinePlus

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - hemodialysis access; dialysis - hemodialysis access

  19. Tipping Points

    NASA Astrophysics Data System (ADS)

    Hansen, J.

    2007-12-01

    A climate tipping point, at least as I have used the phrase, refers to a situation in which a changing climate forcing has reached a point such that little additional forcing (or global temperature change) is needed to cause large, relatively rapid, climate change. Present examples include potential loss of all Arctic sea ice and instability of the West Antarctic and Greenland ice sheets. Tipping points are characterized by ready feedbacks that amplify the effect of forcings. The notion that these may be runaway feedbacks is a misconception. However, present "unrealized" global warming, due to the climate system's thermal inertia, exacerbates the difficulty of avoiding global warming tipping points. I argue that prompt efforts to slow CO2 emissions and absolutely reduce non-CO2 forcings are both essential if we are to avoid tipping points that would be disastrous for humanity and creation, the planet as civilization knows it.

  20. A systematic review and meta-analysis of the diagnostic accuracy of point-of-care tests for the detection of hyperketonemia in dairy cows.

    PubMed

    Tatone, Elise H; Gordon, Jessica L; Hubbs, Jessie; LeBlanc, Stephen J; DeVries, Trevor J; Duffield, Todd F

    2016-08-01

    Several rapid tests for use on farm have been validated for the detection of hyperketonemia (HK) in dairy cattle, however the reported sensitivity and specificity of each method varies and no single study has compared them all. Meta-analysis of diagnostic test accuracy is becoming more common in human medical literature but there are few veterinary examples. The objective of this work was to perform a systematic review and meta-analysis to determine the point-of-care testing method with the highest combined sensitivity and specificity, the optimal threshold for each method, and to identify gaps in the literature. A comprehensive literature search resulted in 5196 references. After removing duplicates and performing relevance screening, 23 studies were included for the qualitative synthesis and 18 for the meta-analysis. The three index tests evaluated in the meta-analysis were: the Precision Xtra(®) handheld device measuring beta-hydroxybutyrate (BHB) concentration in whole blood, and Ketostix(®) and KetoTest(®) semi-quantitative strips measuring the concentration of acetoacetate in urine and BHB in milk, respectively. The diagnostic accuracy of the 3 index tests relative to the reference standard measurement of BHB in serum or whole blood between 1.0-1.4mmol/L was compared using the hierarchical summary receiver operator characteristic (HSROC) method. Subgroup analysis was conducted for each index test to examine the accuracy at different thresholds. The impact of the reference standard threshold, the reference standard method, the prevalence of HK in the population, the primary study source and risk of bias of the primary study was explored using meta-regression. The Precision Xtra(®) device had the highest summary sensitivity in whole blood BHB at 1.2mmol/L, 94.8% (CI95%: 92.6-97.0), and specificity, 97.5% (CI95%: 96.9-98.1). The threshold employed (1.2-1.4mmol/L) did not impact the diagnostic accuracy of the test. The Ketostix(®) and KetoTest(®) strips had

  1. Easy Access

    ERIC Educational Resources Information Center

    Gettelman, Alan

    2009-01-01

    School and university restrooms, locker and shower rooms have specific ADA accessibility requirements that serve the needs of staff, students and campus visitors who are disabled as a result of injury, illness or age. Taking good care of them is good for the reputation of a sensitive community institution, and fosters positive public relations.…

  2. Access Denied

    ERIC Educational Resources Information Center

    Raths, David

    2012-01-01

    As faculty members add online and multimedia elements to their courses, colleges and universities across the country are realizing that there is a lot of work to be done to ensure that disabled students (and employees) have equal access to course material and university websites. Unfortunately, far too few schools consider the task a top priority.…

  3. Expanding Access

    ERIC Educational Resources Information Center

    Roach, Ronald

    2007-01-01

    There is no question that the United States lags behind most industrialized nations in consumer access to broadband Internet service. For many policy makers and activists, this shortfall marks the latest phase in the struggle to overcome the digital divide. To remedy this lack of broadband affordability and availability, one start-up firm--with…

  4. Sharing Clouds: Showing, Distributing, and Sharing Large Point Datasets

    NASA Astrophysics Data System (ADS)

    Grigsby, S.

    2012-12-01

    Sharing large data sets with colleagues and the general public presents a unique technological challenge for scientists. In addition to large data volumes, there are significant challenges in representing data that is often irregular, multidimensional and spatial in nature. For derived data products, additional challenges exist in displaying and providing provenance data. For this presentation, several open source technologies are demonstrated for the remote display and access of large irregular point data sets. These technologies and techniques include the remote viewing of point data using HTML5 and OpenGL, which provides a highly accessible preview of the data sets for a range of audiences. Intermediate levels of accessibility and high levels of interactivity are accomplished with technologies such as wevDAV, which allows collaborators to run analysis on local clients, using data stored and administered on remote servers. Remote processing and analysis, including provenance tracking, will be discussed at the workgroup level. The data sets used for this presentation include data acquired from the NSF funded National Center for Airborne Laser Mapping (NCALM), and data acquired for research and instructional use in NASA's Student Airborne Research Program (SARP). These datasets include Light Ranging And Detection (LiDAR) point clouds ranging in size from several hundred thousand to several hundred million data points; the techniques and technologies discussed are applicable to other forms of irregular point data.

  5. Tipping Point

    MedlinePlus

    ... Tipping Point by CPSC Blogger September 22 appliance child Childproofing CPSC danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash format. Almost weekly, we see ...

  6. Approaching real-time molecular diagnostics: single-pair fluorescence resonance energy transfer (spFRET) detection for the analysis of low abundant point mutations in K-ras oncogenes.

    PubMed

    Wabuyele, Musundi B; Farquar, Hannah; Stryjewski, Wieslaw; Hammer, Robert P; Soper, Steven A; Cheng, Yu-Wei; Barany, Francis

    2003-06-11

    The aim of this study was to develop new strategies for analyzing molecular signatures of disease states approaching real-time using single pair fluorescence resonance energy transfer (spFRET) to rapidly detect point mutations in unamplified genomic DNA. In addition, the detection process was required to discriminate between normal and mutant (minority) DNAs in heterogeneous populations. The discrimination was carried out using allele-specific primers, which flanked the point mutation in the target gene and were ligated using a thermostable ligase enzyme only when the genomic DNA carried this mutation. The allele-specific primers also carried complementary stem structures with end-labels (donor/acceptor fluorescent dyes, Cy5/Cy5.5, respectively), which formed a molecular beacon following ligation. We coupled ligase detection reaction (LDR) with spFRET to identify a single base mutation in codon 12 of a K-ras oncogene that has high diagnostic value for colorectal cancers. A simple diode laser-based fluorescence system capable of interrogating single fluorescent molecules undergoing FRET was used to detect photon bursts generated from the molecular beacon probes formed upon ligation. LDR-spFRET provided the necessary specificity and sensitivity to detect single-point mutations in as little as 600 copies of human genomic DNA directly without PCR at a level of 1 mutant per 1000 wild type sequences using 20 LDR thermal cycles. We also demonstrate the ability to rapidly discriminate single base differences in the K-ras gene in less than 5 min at a frequency of 1 mutant DNA per 10 normals using only a single LDR thermal cycle of genomic DNA (600 copies). Real-time LDR-spFRET detection of point mutations in the K-ras gene was accomplished in PMMA microfluidic devices using sheath flows.

  7. Volatile organic compounds detected in vapor-diffusion samplers placed in sediments along and near the shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, Rhode Island, March-April 1998

    USGS Publications Warehouse

    Lyford, F.P.; Kliever, J.D.; Scott, Clifford

    1999-01-01

    Volatile organic compounds are present in ground water at the Allen Harbor Landfill and the Calf Pasture Point sites on the former Naval Construction Battalion Center in Davisville, R.I. Vapor-diffusion samplers were used at the two sites during March-April 1998 to identify possible discharge points for contaminants along the shore of Allen Harbor and in two wetland areas near the shore. Results from vapor-diffusion samplers will be used in conjunction with other site information to evaluate proposed ground-water monitoring programs. Volatile organic compounds were detected in 41 of 115 samplers placed along the shoreline at the Allen Harbor Landfill. Trichloroethylene was the principal volatile organic compound detected of eight target compounds. The highest vapor concentration measured exceeded 300,000 parts per billion by volume in an area where TCE was detected in groundwater from nearby monitoring wells. Other chemicals detected in vapor-diffusion samplers included tetrachloroethylene, toluene, and benzene. Concentrations of individual volatile organic compounds were less than 100 parts per billion by volume in most samplers. Volatile organic compounds, principally trichloroethylene, were detected in 7 of 30 samplers placed along the shoreline at Calf Pasture Point; the highest trichloroethylene concentration was 1,900 parts per billion by volume. A trace concentration of tetrachloroethylene was detected in one of the samplers. One of 24 samplers placed in two wetland areas near the shore (suspected discharge areas for ground-water containing volatile organic compounds) detected trichloroethylene at a vapor concentration of 14 parts per billion by volume.

  8. Point defects in CdTexSe1-x crystals grown from a Te-rich solution for applications in detecting radiation

    SciTech Connect

    Gul, R.; Roy, U. N.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Hossain, A.; Lee, W.; Yang, G.; Burger, A.; James, R. B.; Cui, Y.

    2015-04-15

    We investigated cadmium telluride selenide (CdTeSe) crystals, newly grown by the Traveling Heater Method (THM), for the presence and abundance of point defects. Deep Level Transient spectroscopy (I-DLTS) was used to determine the energies of the traps, their capture cross sections, and densities. The bias across the detectors was varied from (1–30) V. Four types of point defects were identified, ranging from 10 meV to 0.35 eV. Two dominant traps at energies of 0.18 eV and 0.14 eV were studied in depth. Cd vacancies are found at lower concentrations than other point defects present in the material.

  9. Point defects in CdTexSe1-x crystals grown from a Te-rich solution for applications in detecting radiation

    DOE PAGES

    Gul, R.; Roy, U. N.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Hossain, A.; Lee, W.; Yang, G.; Burger, A.; James, R. B.; et al

    2015-04-15

    We investigated cadmium telluride selenide (CdTeSe) crystals, newly grown by the Traveling Heater Method (THM), for the presence and abundance of point defects. Deep Level Transient spectroscopy (I-DLTS) was used to determine the energies of the traps, their capture cross sections, and densities. The bias across the detectors was varied from (1–30) V. Four types of point defects were identified, ranging from 10 meV to 0.35 eV. Two dominant traps at energies of 0.18 eV and 0.14 eV were studied in depth. Cd vacancies are found at lower concentrations than other point defects present in the material.

  10. Improvement of the Mutation-Discrimination Threshold for Rare Point Mutations by a Separation-Free Ligase Detection Reaction Assay Based on Fluorescence Resonance Energy Transfer.

    PubMed

    Hagihara, Kenta; Tsukagoshi, Kazuhiko; Nakajima, Chinami; Esaki, Shinsuke; Hashimoto, Masahiko

    2016-01-01

    We previously developed a separation-free ligase detection reaction assay based on fluorescence resonance energy transfer from a donor quantum dot to an acceptor fluorescent dye. This assay could successfully detect one cancer mutation among 10 wild-type templates. In the current study, the mutation-discrimination threshold was improved by one order of magnitude by replacing the original acceptor dye (Alexa Fluor 647) with another fluorescent dye (Cyanine 5) that was spectrally similar but more fluorescent. PMID:26960620

  11. Hemodialysis access procedures

    MedlinePlus

    Kidney failure - chronic-dialysis access; Renal failure - chronic-dialysis access; Chronic renal insufficiency-dialysis access; Chronic kidney failure-dialysis access; Chronic renal failure-dialysis access

  12. Evaluation of point mutation detection in Mycobacterium tuberculosis with isoniazid resistance using real-time PCR and TaqMan probe assay.

    PubMed

    Riahi, F; Derakhshan, M; Mosavat, A; Soleimanpour, S; Rezaee, S A

    2015-03-01

    Rapid methods for diagnosis of Mycobacterium tuberculosis (Mtb) drug resistance and choosing appropriate antibiotic treatment are pivotal. Thirty isoniazid (INH)-resistant and 30 INH-susceptible Mtb isolates were evaluated using minimum inhibitory concentration (MIC) method followed by multiplex real-time PCR (RT-PCR). Amplification refractory mutation system (ARMS) for detection of mutation in 315 codon of katG gene and single-nucleotide polymorphism (SNP) for detection of mutation in -15 (C>T) in the regulatory zone of mabA-inhA were carried out using the TaqMan method. Primers and probe were used for IS6110 region of Mtb as an internal amplification control. The sensitivity and specificity of the RT-PCR TaqMan probe for detection of Mtb complex were 100 %. Detection of INH-resistant Mtb using the ARMS method for KatG had 69 % sensitivity and 100 % specificity. The sensitivity and specificity of SNP in mabA-inhA fragment for detection of INH-resistant Mtb were 53 and 100 %, respectively. Furthermore, considering both regions, the sensitivity of RT-PCR has increased to 75 %. This study revealed that the qPCR-TaqMan method can be used as a standard tool for diagnosis of Mtb. Moreover, ARMS and SNP RT-PCR TaqMan methods can be used as rapid screening methods for detection of INH-resistant Mtb.

  13. Bayesian point event modeling in spatial and environmental epidemiology.

    PubMed

    Lawson, Andrew B

    2012-10-01

    This paper reviews the current state of point event modeling in spatial epidemiology from a Bayesian perspective. Point event (or case event) data arise when geo-coded addresses of disease events are available. Often, this level of spatial resolution would not be accessible due to medical confidentiality constraints. However, for the examination of small spatial scales, it is important to be capable of examining point process data directly. Models for such data are usually formulated based on point process theory. In addition, special conditioning arguments can lead to simpler Bernoulli likelihoods and logistic spatial models. Goodness-of-fit diagnostics and Bayesian residuals are also considered. Applications within putative health hazard risk assessment, cluster detection, and linkage to environmental risk fields (misalignment) are considered.

  14. Amplification-free In Situ KRAS Point Mutation Detection at 60 copies/mL in Urine in a Background of 1000-fold Wild Type

    PubMed Central

    KirimLi, Ceyhun E.; Shih, Wei-Heng; Shih, Wan Y.

    2016-01-01

    We have examined in situ detection of single-nucleotide KRAS mutation in urine using a (Pb(Mg1/3Nb2/3)O3)0.65(PbTiO3)0.35 (PMN-PT) piezoelectric plate sensor (PEPS) coated with a 17-nucleotide (nt) locked nucleic acid (LNA) probe DNA complementary to the KRAS mutation. To enhance in situ mutant (MT) DNA detection specificity against the wild type (WT), the detection was carried out in a flow with a flow rate of 4 mL/min and at 63°C with the PEPS vertically situated at the center of the flow in which both the temperature and the flow impingement force discriminated the wild type. Under such conditions, PEPS was shown to specifically detect KRAS MT in situ with 60 copies/mL analytical sensitivity in a background of clinically-relevant 1000-fold more WT in 30 min without DNA isolation, amplification, or labeling. For validation, the detection was followed with detection in a mixture of blue MT fluorescent reporter microspheres (FRMs) (MT FRMs) that bound to only the captured MT and orange WT FRMs that bound to only the captured WT. Microscopic examinations showed that the captured blue MT FRMs still outnumbered the orange WT FRMs by a factor of 4 to 1 even though WT was 1000-fold of MT in urine. Finally, multiplexed specific mutation detection was demonstrated using a 6-PEPS array each with a probe DNA targeting one of the 6 codon-12 KRAS mutations. PMID:26783561

  15. Amplification-free in situ KRAS point mutation detection at 60 copies per mL in urine in a background of 1000-fold wild type.

    PubMed

    Kirimli, Ceyhun E; Shih, Wei-Heng; Shih, Wan Y

    2016-02-21

    We have examined the in situ detection of a single-nucleotide KRAS mutation in urine using a (Pb(Mg1/3Nb2/3)O3)0.65(PbTiO3)0.35 (PMN-PT) piezoelectric plate sensor (PEPS) coated with a 17-nucleotide (nt) locked nucleic acid (LNA) probe DNA complementary to the KRAS mutation. To enhance the in situ mutant (MT) DNA detection specificity against the wild type (WT), detection was carried out in a flow with a flow rate of 4 mL min(-1) and at 63 °C with the PEPS vertically situated at the center of the flow in which both the temperature and the flow impingement force discriminated the wild type. Under such conditions, PEPS was shown to specifically detect KRAS MT in situ with 60 copies per mL analytical sensitivity in a background of clinically-relevant 1000-fold more WT in 30 min without DNA isolation, amplification, or labeling. For validation, this detection was followed with detection in a mixture of blue MT fluorescent reporter microspheres (FRMs) (MT FRMs) that bound to only the captured MT and orange WT FRMs that bound to only the captured WT. Microscopic examinations showed that the captured blue MT FRMs still outnumbered the orange WT FRMs by a factor of 4 to 1 even though WT was 1000-fold of MT in urine. Finally, multiplexed specific mutation detection was demonstrated using a 6-PEPS array each with a probe DNA targeting one of the 6 codon-12 KRAS mutations. PMID:26783561

  16. Characterization of Brazilian accessions of wild Arachis species of section Arachis (Fabaceae) using heterochromatin detection and fluorescence in situ hybridization (FISH)

    PubMed Central

    Custódio, Adriana Regina; Seijo, Guillermo; Valls, José Francisco Montenegro

    2013-01-01

    The cytogenetic characterization of Arachis species is useful for assessing the genomes present in this genus, for establishing the relationship among their representatives and for understanding the variability in the available germplasm. In this study, we used fluorescence in situ hybridization (FISH) to examine the distribution patterns of heterochromatin and rDNA genes in 12 Brazilian accessions of five species of the taxonomic section Arachis. The heterochromatic pattern varied considerably among the species: complements with centromeric bands in all of the chromosomes (A. hoehnei) and complements completely devoid of heterochromatin (A. gregoryi, A. magna) were observed. The number of 45S rDNA loci ranged from two (A. gregoryi) to eight (A. glandulifera), while the number of 5S rDNA loci was more conserved and varied from two (in most species) to four (A. hoehnei). In some species one pair of 5S rDNA loci was observed adjacent to 45S rDNA loci. The chromosomal markers revealed polymorphism in the three species with more than one accession (A. gregoryi, A. magna and A. valida) that were tested. The previous genome assignment for each of the species studied was confirmed, except for A. hoehnei. The intraspecific variability observed here suggests that an exhaustive cytogenetic and taxonomic analysis is still needed for some Arachis species. PMID:24130444

  17. DNA/RNA chimera templates improve the emission intensity and target the accessibility of silver nanocluster-based sensors for human microRNA detection.

    PubMed

    Shah, Pratik; Choi, Suk Won; Kim, Ho-jin; Cho, Seok Keun; Thulstrup, Peter Waaben; Bjerrum, Morten Jannik; Bhang, Yong-Joo; Ahn, Jong Cheol; Yang, Seong Wook

    2015-05-21

    In recent years microRNAs (miRNAs) have been established as important biomarkers in a variety of diseases including cancer, diabetes, cardiovascular disease, aging, Alzheimer's disease, asthma, autoimmune disease and liver diseases. As a consequence, a variety of monitoring methods for miRNAs have been developed, including a fast and simple method for miRNA detection by exploitation of the unique photoluminescence of DNA-templated silver nanoclusters (DNA/AgNCs). To increase the versatility of the AgNC-based method, we have adopted DNA/RNA chimera templates for AgNC-based probes, allowing response from several human miRNAs which are hardly detectable with DNA-based probes. Here, we demonstrate in detail the power of DNA/RNA chimera/AgNC probes in detecting two human miRNAs, let-7a and miR-200c. The DNA/RNA chimera-based probes are highly efficient to determine the level of miRNAs in several human cell lines. PMID:25759134

  18. Prevalence of subclinical ketosis in dairy cattle in the Southwestern Iran and detection of cutoff point for NEFA and glucose concentrations for diagnosis of subclinical ketosis.

    PubMed

    Asl, Ardavan Nowroozi; Nazifi, Saeed; Ghasrodashti, Abbas Rowshan; Olyaee, Ahad

    2011-06-01

    Subclinical ketosis (SCK) is simply a condition marked by increased levels of circulating ketone bodies without the presence of the clinical signs of ketosis. Subclinical ketosis can cause economic losses through decreased milk production and association with preparturient diseases. Limited information is available regarding the prevalence of SCK in dairy herds in Southwestern Iran. The objectives of this study were (i) determination of the cutoff point of nonesterified fatty acids (NEFAs) and glucose concentrations for diagnosis of SCK using receiver operating characteristic (ROC) analysis, and (ii) determination of prevalence of subclinical ketosis in apparently healthy dairy cattle in Southwestern Iran. From October to December 2009, a total of 100 clinically healthy multiparous Holstein cows (3-8 years old) were randomly selected from 16 dairy herds around Kazerun, Fars Province, Iran. The cows had two-six lactations, with body weight ranging from 500 to 650 kg. Blood samples for each cow were taken at 2, 4 and 6 weeks post parturition and 3-4h after the morning feeding. The optimal cutoff point was set, by the ROC method, to >0.26 mmol/L for NEFA, and < 2.26 mmol/L for glucose with corresponding 82.54% sensitivity and 91.89% specificity for NEFA and 44.44% sensitivity and 78.38% specificity for glucose. Cows with BHB concentrations higher than 1200 μmol/L were classified as having SCK. In 2, 4 and 6 weeks post parturition 63%, 68% and 59% of the tested cows were subclinically ketotic. Overall, 97% of tested cows (97/100) were considered subclinically ketotic in at least one sample period. Thirty percent of tested cows (30/100) suffered from subclinical ketosis in all of the 2, 4 and 6 weeks postpartum. The results suggest that, a cut-off point of 0.26 mmol/L for NEFA concentrations can be used during early lactation for diagnosis of subclinical ketosis and making management decisions for prevention and treatment. Glucose cannot be a good criterion for

  19. Evaluation of emplacement sensors for detecting radiation and volatile organic compounds and for long-term monitoring access tubes for the BWCS

    SciTech Connect

    Lord, D.L.; Averill, R.H.

    1997-10-01

    This document evaluates sensors for detecting contaminants in the excavated waste generated by the Buried Waste Containment System (BWCS). The Barrier Placement Machine (BPM) removes spoils from under a landfill or plume and places it on a conveyor belt on the left and right sides of the BPM. The spoils will travel down the conveyor belts past assay monitors and be deposited on top of the site being worked. The belts are 5 ft wide and transport approximately 15 ft3 /minute of spoils. This corresponds to a 10 ft per hour BPM advance rate. With a 2 in. spoils height the belt speed would be 3.6 in. per second. The spoils being removed are expected to be {open_quotes}clean{close_quotes} (no radiation or volatile organics above background levels). To ensure that the equipment is not digging through a contaminated area, assay equipment will monitor the spoils for mg radiation and volatile organic compounds (VOCs). The radiation monitors will check for gross radiation indication. Upon detection of radiation levels above a predetermined setpoint, further evaluation will be performed to determine the isotopes present and their quantity. This will require hand held monitors and a remote monitoring station. Simultaneously, VOC monitors will monitor for predetermined volatile/semi-volatile organic compounds. A Fourier-Transform Infrared Spectrometer (FTIR) monitor is recommended for this operation. Specific site requirements and regulations will determine setpoints and operation scenarios. If VOCs are detected, the data will be collected and recorded. A flat panel display will be mounted in the BPM operator`s cab showing the radio nuclide and VOC monitoring data. As the BPM advances, a 3-in. diameter PVC tube will be placed on the bottom of the barrier slot in front of the 12 to 16-in. containment barrier being emplaced.

  20. Nanoparticle-Drug Bioconjugate as Dual Functional Affinity Ligand for Rapid Point-of-Care Detection of Endotoxin in Water and Serum.

    PubMed

    Kalita, Prasanta; Dasgupta, Anshuman; Sritharan, Venkataraman; Gupta, Shalini

    2015-11-01

    Endotoxin or lipopolysaccharide (LPS) is a major constituent of the Gram-negative bacterial cell wall that causes a life-threatening disorder called septicemia resulting from the unregulated activation of the innate immune system. We demonstrate a simple and robust drug-assisted dot blot bioassay for endotoxin detection that can be used right by the critically ill patients' bedside. Target LPS molecules are trapped from serum or water on glass substrates via long-chain alkyls and tagged with reporter gold nanoparticles (NPs) preconjugated to an antibiotic drug called polymyxin B sulfate (PMB). A post-silver-enhancement step enables signal visibility to the bare eye over a wide and clinically relevant concentration range of 50 fg/mL-50 ng/mL, allowing effortless diagnosis of sepsis at various stages, from early sepsis to septic shock.