WorldWideScience

Sample records for beacon process

  1. Bitcoin Beacon

    OpenAIRE

    Bentov, Iddo; Gabizon, Ariel; Zuckerman, David

    2016-01-01

    We examine a protocol $\\pi_{\\text{beacon}}$ that outputs unpredictable and publicly verifiable randomness, meaning that the output is unknown at the time that $\\pi_{\\text{beacon}}$ starts, yet everyone can verify that the output is close to uniform after $\\pi_{\\text{beacon}}$ terminates. We show that $\\pi_{\\text{beacon}}$ can be instantiated via Bitcoin under sensible assumptions; in particular we consider an adversary with an arbitrarily large initial budget who may not operate at a loss ind...

  2. Ribozyme probe based on molecular beacon for real time monitoring of enzymatic cleavage process

    Institute of Scientific and Technical Information of China (English)

    MENG Xiangxian; WANG Kemin; TAN Weihong; LI Jun; TANG Zhiwen; GUO Qiuping; HUANG Shasheng; LI Du

    2003-01-01

    Ribozyme probe based on molecular beacon (MBR) for monitoring enzymatic cleavage process in real time is designed and studied. The approach relies on ribozyme substrates modified at the two arms, with a fluorescent moiety attached to the end of one arm and a non-fluorescent quenching moiety attached to the end of the other arm. MBR is employed to directly convert the cleavage information into fluorescence signal in real time. Compared with traditional approach, this method provides a no-radiolabeling, sensitive and effective way to research on the ribozyme activity, enzymatic dynamic process and ribozyme function during gene therapy. The activity of the ribozyme against hepatitis C virus RNA (HCV-RNA) is studied based on this assay.

  3. Hyperinflation of surfaces in lower Beacon Valley, Dry Valleys, Antarctica: new process and new clues about fluctuations of Taylor Glacier

    Science.gov (United States)

    Sletten, R. S.; Hallet, B.; Hagedorn, B.; Stone, J.

    2009-12-01

    Soil inflation in dry environments is a common occurrence in areas where extensive desert pavements overlie silt-size particles of eolian origin. Another type of surface inflation, which we term hyperinflation, has been documented in the Dry Valleys where fines drop into contraction cracks that annually open and close 0.5 to 1.5 cm. Particles of local or eolian origin that are smaller than the crack opening can fall into the cracks,. We have cored over 30 m into such a hyperinflated surface in lower Beacon Valley. Large clasts several cm to over 10 m are suspended on top of the finer sediments leading to the characteristic rocky surface of Beacon Valley. These processes have been active over at least several million years based on cosmogenic 10 Be and 26 Al profiles with depth. This new hyperinflation has much in common with the progressive addition of ice into the permafrost in Siberia forming the classic edoma or ice-wedge complexes. We propose that these “sand-wedge complexes” form in a similar way but are only sand because liquid water seldom forms in sufficient amounts to fill the contraction cracks in the hyperarid Beacon Valley. Furthermore, our analysis of a 10-m core collected earlier reveal historical waxing and waning of the Taylor Glacier over lower Beacon Valley in the past several million years; one of these incursions of ice may be responsible for the formation of buried glacial ice found in middle Beacon Valley. We are currently processing our 30-m core and believe that this will improve definition of the extent and chronology of Taylor Glacier advances.

  4. Beacon Node Placement for Minimal Localization Error

    OpenAIRE

    Yuan, Zimu; Li, Wei; Xu, Zhiwei; Zhao, Wei

    2015-01-01

    Beacon node placement, node-to-node measurement, and target node positioning are the three key steps for a localization process. However, compared with the other two steps, beacon node placement still lacks a comprehensive, systematic study in research literatures. To fill this gap, we address the Beacon Node Placment (BNP) problem that deploys beacon nodes for minimal localization error in this paper. BNP is difficult in that the localization error is determined by a complicated combination ...

  5. Personal Beacon

    Science.gov (United States)

    2000-01-01

    The MicroPLB (personal locator beacon) is a search and rescue satellite-aided tracking (SARSAT) transmitter. When activated it emits a distress signal to a constellation of internationally operated satellites. The endangered person's identity and location anywhere on Earth is automatically forwarded to central monitoring stations around the world. It is accurate to within just a few meters. The user uses the device to download navigation data from a global positioning satellite receiver. After the download is complete, the MicroPLB functions as a self-locating beacon. Also, it is the only PLB to use a safe battery. In the past, other PLB devices have used batteries that have enough volatility to explode with extreme force. It was developed by Microwave Monolithic, Inc. through SBIR funding from Glenn Research Center and Goddard Space Flight Center.

  6. High-throughput real-time assay based on molecular beacons for HIV-1 integrase 3'-processing reaction

    Institute of Scientific and Technical Information of China (English)

    Hong-qiu HE; Xiao-hui MA; Bin LIU; Xiao-yi ZHANG; Wei-zu CHEN; Cun-xin WANG; Shao-hui CHENG

    2007-01-01

    Aim: To develop a high-throughput real-time assay based on molecular beacons to monitor the integrase 3'-processing reaction in vitro and apply it to inhibitor screening.Methods: The recombinant human immunodeficiency virus (HIV)-1 integrase (IN) is incubated with a 38 mer oligonucleotide substrate, a sequence identical to the U5 end of HIV-1 long terminal repeats (LTR). Based on the fluores-cence properties of molecular beacons, the substrate is designed to form a stem-loop structure labeled with a fluorophore at the 5' end and a quencher at the 3'end.IN cleaves the terminal 3'-dinucleotide containing the quencher, resulting in an increase in fluorescence which can be monitored on a spectrofluorometer. To optimize this assay, tests were performed to investigate the effects of substrates, enzyme and the metal ion concentrations on the IN activity and optimal param-eters were obtained. Moreover, 2 IN inhibitors were employed to test the perfor-mance of this assay in antiviral compound screening.Results: The fluorescent intensity of the reaction mixture varies linearly with time and is proportional to the velocity of the 3'-processing reaction. Tests were performed and the results showed that the optimal rate was obtained for a reaction mixture containing 50 mg/L recom-binant HIV-1 IN, 400 nmol/L substrate, and 10 mmol/L Mn2+. The IN 3'-processing reaction under the optimal conditions showed a more than 18-fold increase in the fluorescence intensity compared to the enzyme-free control. The IC50 values of the IN inhibitors obtained in our assay were similar to the values obtained from a radiolabeled substrate assay.Conclusion: Our results demonstrated that this is a fast, reliable, and sensitive method to monitor HIV IN 3'-processing reaction and that it can be used for inhibitor screening.

  7. Olympus beacon receiver

    Science.gov (United States)

    Ostergaard, Jens

    1988-01-01

    A medium-size Beacon Receiving System for reception and processing of the B1 (20 GHz) and B2 (30 GHz) beacons from Olympus has been developed. Integration of B1 and B2 receiving equipment into one system using one antenna and a common computer for control and data processing provides the advantages of a compact configuration and synchronization of the two receiver chains. Range for co-polar signal attenuation meaurement is about 30 dB for both beacons, increasing to 40 dB for B2 if the receivers are synchronized to B1. The accuracy is better than 0.5 dB. Cross-polarization discriminations of the order of 10 to 30 dB may be determined with an accuracy of 1 to 2 dB. A number of radiometers for complementary measurements of atmospheric attenuation of 13 to 30 GHz has also been constructed. A small multi-frequency system for operation around 22 GHz and 31 GHz is presently under development.

  8. SILEX beacon equipment

    Science.gov (United States)

    Crepin, P. J.; Leblay, P.; Malaise, D.

    The design and breadboarding of the beacon of the SILEX experimental optical link between geosynchronous Earth orbit and low Earth orbit terminals are considered. The aim of the SILEX experiment is to establish an intersatellite optical telecommunication link. The beacon will provide a powerful continuous wave light beam to allow terminal telescope alignment during acquisition phase. The beacon consists of four parts: the beacon electronics, the beacon emission unit, the optical fiber harness, and the beacon head. The system is described, special attention being given to the optical features.

  9. Special Stamps:Historical Relic Beacons

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In May 2002, the State Postal Bureau issued a set of five stamps picturing historical relic beacons. They are the Mao Beacon, the Jiangxinyu Twin Beacon, the Huaniaoshan Beacon, the Laotieshan Beacon, and

  10. The Effects of Beacons, Comments, and Tasks on Program Comprehension Process in Software Maintenance

    Science.gov (United States)

    Fan, Quyin

    2010-01-01

    Program comprehension is the most important and frequent process in software maintenance. Extensive research has found that individual characteristics of programmers, differences of computer programs, and differences of task-driven motivations are the major factors that affect the program comprehension results. There is no study specifically…

  11. 连续波测速雷达信标测速数据的处理%Beacon Data Processing of Continuous Wave Velocity Radar

    Institute of Scientific and Technical Information of China (English)

    钟水和; 胡松柏; 王正军; 罗鹏飞

    2015-01-01

    连续波测速雷达需在应答机的配合下才能完成目标的捕获、跟踪和测量。针对双频多测速应答机信标测速数据系统误差较大问题,分析了应答机应答和信标测量模式的工作原理,采用直接法和间接法实现了多台测速雷达信标测速数据的综合处理,获取了目标在地心系下x、y、z3个方向的速度分量。试验结果表明:在文中此测速雷达布站和火箭射向模式下,采用直接法解算的速度分量精度优于间接法。%Transponder is needed at target capturing,tracking and measuring for continuous wave( CW) ve-locity measurement radar. To analyze the large system error for the beacon data of dual-band multi-velocity transponder,the principle of respond and beacon measurement mode for transponder is discussed. Direct and indirect methods are applied to synthetically process beacon data of multi-velocity radars. Then,the x,y,z velocity components are obtained. The experiment result shows that the accuracy of direct method is better than that of indirect method in the radars deployment and vehicle launch orientation mode in this paper.

  12. Overshadowing of geometric cues by a beacon in a spatial navigation task.

    Science.gov (United States)

    Redhead, Edward S; Hamilton, Derek A; Parker, Matthew O; Chan, Wai; Allison, Craig

    2013-06-01

    In three experiments, we examined whether overshadowing of geometric cues by a discrete landmark (beacon) is due to the relative saliences of the cues. Using a virtual water maze task, human participants were required to locate a platform marked by a beacon in a distinctively shaped pool. In Experiment 1, the beacon overshadowed geometric cues in a trapezium, but not in an isosceles triangle. The longer escape latencies during acquisition in the trapezium control group with no beacon suggest that the geometric cues in the trapezium were less salient than those in the triangle. In Experiment 2, we evaluated whether generalization decrement, caused by the removal of the beacon at test, could account for overshadowing. An additional beacon was placed in an alternative corner. For the control groups, the beacons were identical; for the overshadow groups, they were visually unique. Overshadowing was again found in the trapezium. In Experiment 3, we tested whether the absence of overshadowing in the triangle was due to the geometric cues being more salient than the beacon. Following training, the beacon was relocated to a different corner. Participants approached the beacon rather than the trained platform corner, suggesting that the beacon was more salient. These results suggest that associative processes do not fully explain cue competition in the spatial domain.

  13. Snapshot analysis for rhodium fixed incore detector using BEACON methodology

    International Nuclear Information System (INIS)

    The purpose of this report is to process the rhodium detector data of the Yonggwang nuclear unit 4 cycle 5 core for the measured power distribution by using the BEACON methodology. Rhodium snapshots of the YGN 4 cycle 5 have been analyzed by both BEACON/SPINOVA and CECOR to compare the results of both codes. By analyzing a large number of snapshots obtained during normal plant operation. Reviewing the results of this analysis, the BEACON/SPNOVA can be used for the snapshot analysis of Korean Standard Nuclear Power (KSNP) plants

  14. The laser beacon

    International Nuclear Information System (INIS)

    Given the small sagitta of a few millimeters of high energetic muons in the L3 Muon Spectrometer at LEP (CERN) and the enormous dimensions (75 m2 x 14 m) of this instrument, it is evident that alignment is the most critical task for its proper evaluation. In the chambers of each of the sixteen modules ('octants'), which form the spectrometer, wire planes are precisely positioned with respect to the front side and the rear side centerlines. A novel system - the Laser Beacon System - allows to make these centerlines coplanar within 25 μ rad by the aid of a reference plane defined by a sweeping laser beam. This restricts a possible torsion induced systematic momentum error for a 50 GeV/c muon to 0.25%. The main design and production features of the Laser Beacon System are described. Results of measurements in test assemblies and in the octants are given. (orig.)

  15. Molecular Beacon-Based MicroRNA Imaging During Neurogenesis.

    Science.gov (United States)

    Lee, Jonghwan; Kim, Soonhag

    2016-01-01

    The fluorescence monitoring system for examining endogenous microRNA (miRNA) activity in cellular level provides crucial information on not only understanding a critical role of miRNA involving a variety of biological processes, but also evaluating miRNA expression patterns in a noninvasive manner. In this protocol, we report the details of a new procedure for a molecular beacon-based miRNA monitoring system, which includes the illustration scheme for miRNA detection strategy, exogenous miRNA detection, and measurement of endogenous miRNA expression level during neurogenesis. The fluorescence signal of miR-124a beacon quenched by BHQ2 was gradually recovered as increasing concentration of the miR-124a in tube. The functional work of miR-124a beacon was examined in intracellular environment, allowing for the internalization of the miR-124a beacon by lipofectamine, which resulted in activated fluorescent signals of the miR-124a beacon in the HeLa cells after the addition of synthetic miR-124a. The endogenous miR-124a expression level was detected by miR-124a beacon system during neurogenesis, showing brighter fluorescence intensity in cytoplasmic area of P19 cells after induction of neuronal differentiation by retinoic acid. The molecular beacon based-miRNA detection technique could be applicable to the simultaneous visualization of a variety of miRNA expression patterns using different fluorescence dyes. For the study of examining endogenous miRNA expression level using miRNA-beacon system, if cellular differentiation step is already prepared, transfection step of miR-124a beacon into P19 cells, and acquisition of activated fluorescence signal measured by confocal microscope can be conducted approximately within 6 h. PMID:26530921

  16. Molecular Beacon-Based MicroRNA Imaging During Neurogenesis.

    Science.gov (United States)

    Lee, Jonghwan; Kim, Soonhag

    2016-01-01

    The fluorescence monitoring system for examining endogenous microRNA (miRNA) activity in cellular level provides crucial information on not only understanding a critical role of miRNA involving a variety of biological processes, but also evaluating miRNA expression patterns in a noninvasive manner. In this protocol, we report the details of a new procedure for a molecular beacon-based miRNA monitoring system, which includes the illustration scheme for miRNA detection strategy, exogenous miRNA detection, and measurement of endogenous miRNA expression level during neurogenesis. The fluorescence signal of miR-124a beacon quenched by BHQ2 was gradually recovered as increasing concentration of the miR-124a in tube. The functional work of miR-124a beacon was examined in intracellular environment, allowing for the internalization of the miR-124a beacon by lipofectamine, which resulted in activated fluorescent signals of the miR-124a beacon in the HeLa cells after the addition of synthetic miR-124a. The endogenous miR-124a expression level was detected by miR-124a beacon system during neurogenesis, showing brighter fluorescence intensity in cytoplasmic area of P19 cells after induction of neuronal differentiation by retinoic acid. The molecular beacon based-miRNA detection technique could be applicable to the simultaneous visualization of a variety of miRNA expression patterns using different fluorescence dyes. For the study of examining endogenous miRNA expression level using miRNA-beacon system, if cellular differentiation step is already prepared, transfection step of miR-124a beacon into P19 cells, and acquisition of activated fluorescence signal measured by confocal microscope can be conducted approximately within 6 h.

  17. Portable-Beacon Landing System for Helicopters

    Science.gov (United States)

    Davis, Thomas J.; Clary, George R.; Chisholm, John P.; Macdonald, Stanley L.

    1987-01-01

    Prototype beacon landing system (BLS) allows helicopters to make precise landings in all weather. BLS easily added to existing helicopter avionic equipment and readily deployed at remote sites. Small and light, system employs X-band radar and digital processing. Variety of beams pulsed sequentially by ground station after initial interrogation by weather radar of approaching helicopter. Airborne microprocessor processes pulses to determine glide slope, course deviation, and range.

  18. Mobile-Beacon Assisted Sensor Localization with Dynamic Beacon Mobility Scheduling

    OpenAIRE

    Li, Xu; Mitton, Nathalie; Simplot-Ryl, Isabelle; Simplot-Ryl, David

    2011-01-01

    International audience In mobile-beacon assisted sensor localization, beacon mobility scheduling aims to determine the best beacon trajectory so that each sensor receives sufficient beacon signals with minimum delay. We propose a novel DeteRministic bEAcon Mobility Scheduling (DREAMS) algorithm, without requiring any prior knowledge of the sensory field. In this algorithm, beacon trajectory is defined as the track of depth-first traversal (DFT) of the network graph, thus deterministic. The...

  19. Decimal Integer Multiplication based on Molecular Beacons

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2013-12-01

    Full Text Available Due to the enhancement of circuit integration level, and the accelerating of working frequency of traditional computer, it requires components dimension must be constantly decreased. So encapsulation, etching and other problems of chip are becoming more and more difficult to solve, which causes its performance also become unstable. In order to overcome this problem, DNA computing as a new kind of molecular computing mode, with its high parallelism, huge amounts of storage capacity, low energy consumption advantages has received extensive attention. Being the same with traditional electronic computer, DNA computer is composed by arithmetic operations such as addition, subtraction, multiplication and dividing and basic logic units such as AND, OR, NON gate. This paper puts forward a new method to realize decimal integer multiplication based on molecular beacons. The algorithm firstly converts decimal integer to binary number, and then resolves the multiplication process into multiplication of current bit and addition of intermediate result after shifting two steps. Molecular beacon is used as multiplying unit, coding sequence is used as multiplier in this method. Based on the working principle of molecular beacon, multiplication operation of two one-bit binary is simulated. And by recording fluorescence status of molecular beacon to observe intermediate result and carry-bit situation, the final result can be obtained through addition after shifting. Examples prove that this method can realize decimal integer multiplication rapidly and accurately. This method is similar to multiplication system in traditional electronic computer, and it provides a simple, easier operation method for DNA computer to realize arithmetic operation.

  20. 47 CFR 97.203 - Beacon station.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Beacon station. 97.203 Section 97.203... SERVICE Special Operations § 97.203 Beacon station. (a) Any amateur station licensed to a holder of a Technician, Technician Plus, General, Advanced or Amateur Extra Class operator license may be a beacon....

  1. Weak beacon detection for air-to-ground optical wireless link establishment.

    Science.gov (United States)

    Han, Yaoqiang; Dang, Anhong; Tang, Junxiong; Guo, Hong

    2010-02-01

    In an air-to-ground free-space optical communication system, strong background interference seriously affects the beacon detection, which makes it difficult to establish the optical link. In this paper, we propose a correlation beacon detection scheme under strong background interference conditions. As opposed to traditional beacon detection schemes, the beacon is modulated by an m-sequence at the transmitting terminal with a digital differential matched filter (DDMF) array introduced at the receiving end to detect the modulated beacon. This scheme is capable of suppressing both strong interference and noise by correlation reception of the received image sequence. In addition, the DDMF array enables each pixel of the image sensor to have its own DDMF of the same structure to process its received image sequence in parallel, thus it makes fast beacon detection possible. Theoretical analysis and an outdoor experiment have been demonstrated and show that the proposed scheme can realize fast and effective beacon detection under strong background interference conditions. Consequently, the required beacon transmission power can also be reduced dramatically.

  2. Protein analysis based on molecular beacon probes and biofunctionalized nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the completion of the human genome-sequencing project, there has been a resulting change in the focus of studies from genomics to proteomics. By utilizing the inherent advantages of molecular beacon probes and biofunctionalized nanoparticles, a series of novel principles, methods and techniques have been exploited for bioanalytical and biomedical studies. This review mainly discusses the applications of molecular beacon probes and biofunctionalized nanoparticles-based technologies for realtime, in-situ, highly sensitive and highly selective protein analysis, including the nonspecific or specific protein detection and separation, protein/DNA interaction studies, cell surface protein recognition, and antigen-antibody binding process-based bacteria assays. The introduction of molecular beacon probes and biofunctionalized nanoparticles into the protein analysis area would necessarily advance the proteomics research.

  3. New frontiers of molecular beacons: signal amplification and nanomachines

    DEFF Research Database (Denmark)

    Della Vedova, Paolo

    2013-01-01

    Gene expression is the process in which information stored into a gene is used to create a functional gene product, for example a protein or a functional RNA. Gene expression is used by all living organism to control cell life, differentiation, regeneration and cancer genesis. Molecular beacons...... provide a useful way to detect gene expression inside living cells without influencing the cell behavior. Molecular beacons are a particular kind of nucleic acid based probes composed by an oligonucleotide chain which assumes a hairpin configuration, encoding the target sequence of interest (loop) flanked...... section gives initially an overview of the molecular beacon technology usability and working principle. Later on the mechanism of molecular beacon’s internalization by SLO treatment was theoretically and experimentally investigated to determine optimal transfection condition and actual cell loading...

  4. Positioning beacon system using digital camera and LEDs

    OpenAIRE

    Liu, HS; G. Pang

    2003-01-01

    This paper is on a novel use of lighting or signaling devices constructed by light-emitting diodes (LEDs) as a positioning beacon. The idea is that the surface of the LED lighting device is divided into regions and used to show different visual patterns that are not noticeable by the human eye due to the high-frequency switching of the LEDs. A digital camera is used as a receiver to capture a sequence of images of the LED positioning beacon transmitter. Image-processing algorithms are used to...

  5. Evolution of stratospheric chemistry in the Saturn storm beacon region

    Science.gov (United States)

    Moses, Julianne I.; Armstrong, Eleanor S.; Fletcher, Leigh N.; Friedson, A. James; Irwin, Patrick G. J.; Sinclair, James A.; Hesman, Brigette E.

    2015-11-01

    The giant northern-hemisphere storm that erupted on Saturn in December 2010 triggered significant changes in stratospheric temperatures and species abundances that persisted for more than a year after the original outburst. The stratospheric regions affected by the storm have been nicknamed "beacons" due to their prominent infrared-emission signatures (Fletcher, L.N. et al. [2011]. Science 332, 1413). The two beacon regions that were present initially merged in April 2011 to form a single, large, anticyclonic vortex (Fletcher, L.N. et al. [2012]. Icarus 221, 560). We model the expected photochemical evolution of the stratospheric constituents in the beacons from the initial storm onset through the merger and on out to March 2012. The results are compared with longitudinally resolved Cassini/CIRS spectra from May 2011. If we ignore potential changes due to vertical winds within the beacon, we find that C2H2, C2H6, and C3H8 remain unaffected by the increased stratospheric temperatures in the beacon, the abundance of the shorter-lived CH3C2H decreases, and the abundance of C2H4 increases significantly due to the elevated temperatures, the latter most notably in a secondary mixing-ratio peak located near mbar pressures. The C4H2 abundance in the model decreases by a factor of a few in the 0.01-10 mbar region but has a significant increase in the 10-30 mbar region due to evaporation of the previously condensed phase. The column abundances of C6H6 and H2O above ∼30 mbar also increase due to aerosol evaporation. Model-data comparisons show that models that consider temperature changes alone underpredict the abundance of C2Hx species by a factor of 2-7 in the beacon core in May 2011, suggesting that other processes not considered by the models, such as downwelling winds in the vortex, are affecting the species profiles. Additional calculations indicate that downwelling winds of order - 10 cm s-1 near ∼0.1 mbar need to be included in the photochemical models in order to

  6. 78 FR 75392 - American Beacon Funds, et al.; Notice of Application

    Science.gov (United States)

    2013-12-11

    ... COMMISSION American Beacon Funds, et al.; Notice of Application December 5, 2013. AGENCY: Securities and... (Jun. 25, 1996) (order). Applicants: American Beacon Funds and American Beacon Select Funds (collectively, the ``Trusts'') and American Beacon Advisors, Inc. (``American Beacon'' and...

  7. Detection of MDR1 mRNA expression with optimized gold nanoparticle beacon

    Science.gov (United States)

    Zhou, Qiumei; Qian, Zhiyu; Gu, Yueqing

    2016-03-01

    MDR1 (multidrug resistance gene) mRNA expression is a promising biomarker for the prediction of doxorubicin resistance in clinic. However, the traditional technical process in clinic is complicated and cannot perform the real-time detection mRNA in living single cells. In this study, the expression of MDR1 mRNA was analyzed based on optimized gold nanoparticle beacon in tumor cells. Firstly, gold nanoparticle (AuNP) was modified by thiol-PEG, and the MDR1 beacon sequence was screened and optimized using a BLAST bioinformatics strategy. Then, optimized MDR1 molecular beacons were characterized by transmission electron microscope, UV-vis and fluorescence spectroscopies. The cytotoxicity of MDR1 molecular beacon on L-02, K562 and K562/Adr cells were investigated by MTT assay, suggesting that MDR1 molecular beacon was low inherent cytotoxicity. Dark field microscope was used to investigate the cellular uptake of hDAuNP beacon assisted with ultrasound. Finally, laser scanning confocal microscope images showed that there was a significant difference in MDR1 mRNA expression in K562 and K562/Adr cells, which was consistent with the results of q-PCR measurement. In summary, optimized MDR1 molecular beacon designed in this study is a reliable strategy for detection MDR1 mRNA expression in living tumor cells, and will be a promising strategy for in guiding patient treatment and management in individualized medication.

  8. Designing reduced beacon trajectory for sensor localization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Localization is one of the substantial issues in wireless sensor networks. The key problem for the mobile beacon localization is how to choose the appropriate beacon trajectory. However, little research has been done on it. In this paper, firstly,we deduce the number of positions for a beacon to send a packet according to the acreage of ROI (region of interest); and next we present a novel method based on virtual force to arrange the positions in arbitrary ROI; then we apply TSP (travelling salesman problem) algorithm to the positions sequence to obtain the optimal touring path, i.e. the reduced beacon trajectory. When a mobile beacon moves along the touring path, sending RF signals at every position, the sensors in ROI can work out their position with trilateration. Experimental results demonstrate that the localization method, based on the beacon reduced path, is efficient and has flexible accuracy.

  9. Polarization Methods of Measuring the Roll Angle of an Object in Motion in Radio Beacon Navigation Systems

    Science.gov (United States)

    Gulko, V. L.; Mescheryakov, A. A.

    2016-06-01

    Polarization methods of measuring the roll angle of an object in motion with the help of radio beacon systems are considered. The polarization properties of the beacon signals received on board the object and amplitude-phase processing of their orthogonal polarized components are used to accomplish this goal.

  10. A Learning Approach to Decentralised Beacon Scheduling

    OpenAIRE

    Cano, C.; Malone, D

    2016-01-01

    Accepted for publication in Elsevier Ad-Hoc Networks Beaconing is usually employed to allow network discovery and to maintain synchronisation in mesh networking protocols, such as those defined in the IEEE 802.15.4e and IEEE 802.11s standards. Thus, avoiding persistent or consecutive collisions of beacons is crucial in order to ensure correct network operation. Beacons are also used in receiver-initiated medium access protocols to advertise that nodes are awake. Consequently, effective bea...

  11. Smartphone-Based Indoor Localization with Bluetooth Low Energy Beacons

    Directory of Open Access Journals (Sweden)

    Yuan Zhuang

    2016-04-01

    Full Text Available Indoor wireless localization using Bluetooth Low Energy (BLE beacons has attracted considerable attention after the release of the BLE protocol. In this paper, we propose an algorithm that uses the combination of channel-separate polynomial regression model (PRM, channel-separate fingerprinting (FP, outlier detection and extended Kalman filtering (EKF for smartphone-based indoor localization with BLE beacons. The proposed algorithm uses FP and PRM to estimate the target’s location and the distances between the target and BLE beacons respectively. We compare the performance of distance estimation that uses separate PRM for three advertisement channels (i.e., the separate strategy with that use an aggregate PRM generated through the combination of information from all channels (i.e., the aggregate strategy. The performance of FP-based location estimation results of the separate strategy and the aggregate strategy are also compared. It was found that the separate strategy can provide higher accuracy; thus, it is preferred to adopt PRM and FP for each BLE advertisement channel separately. Furthermore, to enhance the robustness of the algorithm, a two-level outlier detection mechanism is designed. Distance and location estimates obtained from PRM and FP are passed to the first outlier detection to generate improved distance estimates for the EKF. After the EKF process, the second outlier detection algorithm based on statistical testing is further performed to remove the outliers. The proposed algorithm was evaluated by various field experiments. Results show that the proposed algorithm achieved the accuracy of <2.56 m at 90% of the time with dense deployment of BLE beacons (1 beacon per 9 m, which performs 35.82% better than <3.99 m from the Propagation Model (PM + EKF algorithm and 15.77% more accurate than <3.04 m from the FP + EKF algorithm. With sparse deployment (1 beacon per 18 m, the proposed algorithm achieves the accuracies of <3.88 m at

  12. Smartphone-Based Indoor Localization with Bluetooth Low Energy Beacons.

    Science.gov (United States)

    Zhuang, Yuan; Yang, Jun; Li, You; Qi, Longning; El-Sheimy, Naser

    2016-01-01

    Indoor wireless localization using Bluetooth Low Energy (BLE) beacons has attracted considerable attention after the release of the BLE protocol. In this paper, we propose an algorithm that uses the combination of channel-separate polynomial regression model (PRM), channel-separate fingerprinting (FP), outlier detection and extended Kalman filtering (EKF) for smartphone-based indoor localization with BLE beacons. The proposed algorithm uses FP and PRM to estimate the target's location and the distances between the target and BLE beacons respectively. We compare the performance of distance estimation that uses separate PRM for three advertisement channels (i.e., the separate strategy) with that use an aggregate PRM generated through the combination of information from all channels (i.e., the aggregate strategy). The performance of FP-based location estimation results of the separate strategy and the aggregate strategy are also compared. It was found that the separate strategy can provide higher accuracy; thus, it is preferred to adopt PRM and FP for each BLE advertisement channel separately. Furthermore, to enhance the robustness of the algorithm, a two-level outlier detection mechanism is designed. Distance and location estimates obtained from PRM and FP are passed to the first outlier detection to generate improved distance estimates for the EKF. After the EKF process, the second outlier detection algorithm based on statistical testing is further performed to remove the outliers. The proposed algorithm was evaluated by various field experiments. Results show that the proposed algorithm achieved the accuracy of <2.56 m at 90% of the time with dense deployment of BLE beacons (1 beacon per 9 m), which performs 35.82% better than <3.99 m from the Propagation Model (PM) + EKF algorithm and 15.77% more accurate than <3.04 m from the FP + EKF algorithm. With sparse deployment (1 beacon per 18 m), the proposed algorithm achieves the accuracies of <3.88 m at 90% of the

  13. An Adaptive Scheme for Robot Localization and Mapping with Dynamically Configurable Inter-Beacon Range Measurements

    OpenAIRE

    Arturo Torres-González; Jose Ramiro Martinez-de Dios; Anibal Ollero

    2014-01-01

    This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons) are used as landmarks for range-only (RO) simultaneous localization and mapping (SLAM). This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and i...

  14. Development of a Universal RNA Beacon for Exogenous Gene Detection

    OpenAIRE

    Guo, Yuanjian; Lu, Zhongju; Cohen, Ira Stephen; Scarlata, Suzanne

    2015-01-01

    RNA beacon technology is a promising method to detect and separate cells expressing a particular gene, but developing a successful, specific beacon can take months and in some cases is impossible. This study reports an off-the-shelf universal beacon that decreases the time and cost of applying beacon technology to select any living cell population transfected with an exogenous gene.

  15. An Adaptive Scheme for Robot Localization and Mapping with Dynamically Configurable Inter-Beacon Range Measurements

    Directory of Open Access Journals (Sweden)

    Arturo Torres-González

    2014-04-01

    Full Text Available This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons are used as landmarks for range-only (RO simultaneous localization and mapping (SLAM. This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and inter-beacon measurements with different inter-beacon depth levels and at different rates. It also includes a supervision module that monitors the SLAM performance and dynamically selects the measurement gathering configuration balancing SLAM accuracy and resource consumption. The proposed scheme has been applied to an extended Kalman filter SLAM with auxiliary particle filters for beacon initialization (PF-EKF SLAM and validated with experiments performed in the CONET Integrated Testbed. It achieved lower map and robot errors (34% and 14%, respectively than traditional methods with a lower computational burden (16% and similar beacon energy consumption.

  16. An adaptive scheme for robot localization and mapping with dynamically configurable inter-beacon range measurements.

    Science.gov (United States)

    Torres-González, Arturo; Martinez-de Dios, Jose Ramiro; Ollero, Anibal

    2014-04-25

    This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons) are used as landmarks for range-only (RO) simultaneous localization and mapping (SLAM). This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and inter-beacon measurements with different inter-beacon depth levels and at different rates. It also includes a supervision module that monitors the SLAM performance and dynamically selects the measurement gathering configuration balancing SLAM accuracy and resource consumption. The proposed scheme has been applied to an extended Kalman filter SLAM with auxiliary particle filters for beacon initialization (PF-EKF SLAM) and validated with experiments performed in the CONET Integrated Testbed. It achieved lower map and robot errors (34% and 14%, respectively) than traditional methods with a lower computational burden (16%) and similar beacon energy consumption.

  17. The ANTARES optical beacon system

    International Nuclear Information System (INIS)

    ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three-dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular, when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented

  18. The ANTARES optical beacon system

    Energy Technology Data Exchange (ETDEWEB)

    Ageron, M. [CPPM - Centre de Physique des Particules de Marseille, CNRS/IN2P3 et Universite de la Mediterranee, 163 Avenue de Luminy, Case 902, 13288 Marseille Cedex 9 (France); Aguilar, J.A. [IFIC - Instituto de Fisica Corpuscular, Edificios de Investigacion de Paterna, CSIC - Universitat de Valencia, Apdo. de Correos 22085, 46071 Valencia (Spain)]. E-mail: J.A.Aguilar@ific.uv.es; Albert, A. [GRPHE - Groupe de Recherche en Physique des Hautes Energies, Universite de Haute Alsace, 61 Rue Albert Camus, 68093 Mulhouse Cedex (France)) (and others)

    2007-08-11

    ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three-dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular, when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented.

  19. Searching for Cost Optimized Interstellar Beacons

    CERN Document Server

    Benford, Gregory; Benford, Dominic

    2009-01-01

    What would SETI Beacon transmitters be like if built by civilizations with a variety of motivations, but who cared about cost? We studied in a companion paper how, for fixed power density in the far field, we could build a cost-optimum interstellar Beacon system. Here we consider, if someone like us were to produce a Beacon, how should we look for it? High-power transmitters might be built for wide variety of motives other than twoway communication; Beacons built to be seen over thousands of light years are such. Altruistic Beacon builders will have to contend with other altruistic causes, just as humans do, so may select for economy of effort. Cost, spectral lines near 1 GHz and interstellar scintillation favor radiating frequencies substantially above the classic water hole. Therefore the transmission strategy for a distant, cost-conscious Beacon will be a rapid scan of the galactic plane, to cover the angular space. Such pulses will be infrequent events for the receiver. Such Beacons built by distant advan...

  20. Uncertainty evaluation in BEACON power distribution monitoring

    International Nuclear Information System (INIS)

    BEACON is an advanced operational core support package that has a three-dimensional nodal code as its cornerstone. The three-dimensional calculation includes all necessary pressurized water reactor feedback effects. The generation of the measured power distribution from the core instrumentation is one of the primary functions of the core-monitoring software. The purpose of this paper is to discuss evaluation of the uncertainty in the measured assembly power from the BEACON system. The study covers not only the normal operating conditions, but off-normal situations to demonstrate BEACON's applicability for that condition

  1. Beacon core monitoring system: load follow qualification

    International Nuclear Information System (INIS)

    The BEACON operational core monitoring and support system was used to analyze a load swing maneuver. This analysis showed the ability of BEACON to predict and monitor these conditions and serves as the basis for the qualification of BEACON in load swing operation. The results demonstrate the capability to predict the reactivity transients as a result of the xenon depletion, power defect and control rod position. They also show the reliability of using the core exit thermocouples to predict the radial power distribution throughout the transient

  2. The ANTARES Optical Beacon System

    CERN Document Server

    Ageron, M; Albert, A; Ameli, F; Anghinolfi, M; Anton, G; Anvar, S; Ardellier-Desages, F; Aslanides, E; Aubert, J J; Auer, R; Barbarito, E; Basa, S; Battaglieri, M; Becherini, Y; Beltramelli, J; Bertin, V; Bigi, A; Billault, M; Blaes, R; De Botton, N R; Bouwhuis, M C; Bradbury, S M; Bruijn, R; Brunner, J; Burgio, G F; Busto, J; Cafagna, F; Caillat, L; Calzas, A; Capone, A; Caponetto, L; Carmona, E; Carr, J; Cartwright, S L; Castel, D; Castorina, E; Cavasinni, V; Cecchini, S; Ceres, A; Charvis, P; Chauchot, P; Chiarusi, T; Circella, M; Colnard, C; Compere, C; Coniglione, R; Cottini, N; Coyle, P; Cuneo, S; Cussatlegras, A S; Damy, G; Van Dantzig, R; De Bonis, G; De Marzo, C; De Vita, R; Dekeyser, I; Delagnes, E; Denans, D; Deschamps, A; Destelle, J J; Dinkespieler, B; Distefano, C; Donzaud, C; Drogou, J F; Druillole, F; Durand, D; Ernenwein, J P; Escoffier, S; Falchini, E; Favard, S; Fehr, F; Feinstein, F; Ferry, S; Fiorello, C; Flaminio, V; Fratini, K; Fuda, J L; Galeotti, S; Gallone, J M; Giacomelli, G; Girard, N; Gojak, C; Goret, P; Graf, K; Hallewell, G; Harakeh, M N; Hartmann, B; Heijboer, A; Heine, E; Hello, Y; Hernández-Rey, J J; Hossl, J; Hoffman, C; Hogenbirk, J; Hubbard, John R; Jaquet, M; Jaspers, M; De Jong, M; Jouvenot, F; Kalantar-Nayestanaki, N; Kappes, A; Karg, T; Katz, U; Keller, P; Kok, E; Kok, H; Kooijman, P; Kopper, C; Korolkova, E V; Kouchner, A; Kretschmer, W; Kruijer, A; Kuch, S; Kudryavtsev, V A; Lagier, P; Lahmann, R; Lamanna, G; Lamare, P; Lambard, G; Languillat, J C; Laschinsky, H; Lavalle, J; Le Guen, Y; Le Provost, H; Le Van-Suu, A; Lefèvre, D; Legou, T; Lelaizant, G; Lim, G; Lo Presti, D; Löhner, H; Loucatos, Sotirios S; Louis, F; Lucarelli, F; Lyashuk, V; Marcelin, M; Margiotta, A; Masullo, R; Mazéas, F; Mazure, A; McMillan, J E; Megna, R; Melissas, M; Migneco, E; Milovanovic, A; Mongelli, M; Montaruli, T; Morganti, M; Moscoso, L; Musumeci, M; Naumann-Godo, M; Naumann, C; Niess, V; Noble, T; Olivetto, C; Ostasch, R; Palanque-Delabrouille, Nathalie; Payre, P; Peek, H; Pérez, A; Petta, C; Piattelli, P; Pillet, R; Pineau, J P; Poinsignon, J; Popa, V; Pradier, T; Racca, C; Randazzo, N; Van Randwijk, J; Real, D; Van Rens, B; Rethore, F; Rewiersma, P A M; Riccobene, G; Rigaud, V; Ripani, M; Roca, V; Roda, C; Rolin, J F; Rose, H J; Rostovtsev, A; Roux, J; Ruppi, M; Russo, G V; Rusydi, G; Salesa, F; Salomon, K; Sapienza, P; Schmitt, F; Schuller, J P; Shanidze, R; Sokalski, I A; Spona, T; Spurio, M; van der Steenhoven, G; Stolarczyk, T; Streeb, K; Sulak, L; Taiuti, M; Tamburini, C; Tao, C; Terreni, G; Thompson, L F; Urbano, F; Valdy, P; Valente, V; Vallage, B; Vaudaine, G; Venekamp, G; Verlaat, B; Vernin, P; De Vries-Uiterweerd, G; Van Wijk, R; Wijnker, G; De Witt-Huberts, P K A; Wobbe, G; De Wolf, E; Yao, A F; Zaborov, D; Zaccone, Henri; De Dios-Zornoza-Gomez, Juan; Zúñiga, J; al, et

    2007-01-01

    ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of ...

  3. Direct Selection of RNA Beacon Aptamers

    OpenAIRE

    Morse, Daniel P.

    2007-01-01

    A method for the direct selection of RNA molecules that can be easily converted into beacon aptamers is presented. Beacon aptamers are fluorescently labeled nucleic acids that signal the presence of a specific ligand through changes in fluorescence intensity. Typically, ligand binding causes an increase in fluorescence intensity by inducing a conformational change that separates a fluorophore/quencher pair. The method presented here simultaneously selects for ligand binding and induction of a...

  4. Searching for Cost-Optimized Interstellar Beacons

    Science.gov (United States)

    Benford, Gregory; Benford, James; Benford, Dominic

    2010-01-01

    What would SETI beacon transmitters be like if built by civilizations that had a variety of motives but cared about cost? In a companion paper, we presented how, for fixed power density in the far field, a cost-optimum interstellar beacon system could be built. Here, we consider how we should search for a beacon if it were produced by a civilization similar to ours. High-power transmitters could be built for a wide variety of motives other than the need for two-way communication, this would include beacons built to be seen over thousands of light-years. Extraterrestrial beacon builders would likely have to contend with economic pressures just as their terrestrial counterparts do. Cost, spectral lines near 1GHz, and interstellar scintillation favor radiating frequencies substantially above the classic "water hole." Therefore, the transmission strategy for a distant, cost-conscious beacon would be a rapid scan of the galactic plane with the intent to cover the angular space. Such pulses would be infrequent events for the receiver. Such beacons built by distant, advanced, wealthy societies would have very different characteristics from what SETI researchers seek. Future searches should pay special attention to areas along the galactic disk where SETI searches have seen coherent signals that have not recurred on the limited listening time intervals we have used. We will need to wait for recurring events that may arrive in intermittent bursts. Several new SETI search strategies have emerged from these ideas. We propose a new test for beacons that is based on the Life Plane hypotheses.

  5. Beacon data acquisition and display system

    Science.gov (United States)

    Skogmo, David G.; Black, Billy D.

    1991-01-01

    A system for transmitting aircraft beacon information received by a secondary surveillance radar through telephone lines to a remote display includes a digitizer connected to the radar for preparing a serial file of data records containing position and identification information of the beacons detected by each sweep of the radar. This information is transmitted through the telephone lines to a remote computer where it is displayed.

  6. Adapting Mobile Beacon-Assisted Localization in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Wei Dong

    2009-04-01

    Full Text Available The ability to automatically locate sensor nodes is essential in many Wireless Sensor Network (WSN applications. To reduce the number of beacons, many mobile-assisted approaches have been proposed. Current mobile-assisted approaches for localization require special hardware or belong to centralized localization algorithms involving some deterministic approaches due to the fact that they explicitly consider the impreciseness of location estimates. In this paper, we first propose a range-free, distributed and probabilistic Mobile Beacon-assisted Localization (MBL approach for static WSNs. Then, we propose another approach based on MBL, called Adapting MBL (A-MBL, to increase the efficiency and accuracy of MBL by adapting the size of sample sets and the parameter of the dynamic model during the estimation process. Evaluation results show that the accuracy of MBL and A-MBL outperform both Mobile and Static sensor network Localization (MSL and Arrival and Departure Overlap (ADO when both of them use only a single mobile beacon for localization in static WSNs.

  7. Messaging with Cost-Optimized Interstellar Beacons

    Science.gov (United States)

    Benford, James; Benford, Gregory; Benford, Dominic

    2010-01-01

    On Earth, how would we build galactic-scale beacons to attract the attention of extraterrestrials, as some have suggested we should do? From the point of view of expense to a builder on Earth, experience shows an optimum trade-off. This emerges by minimizing the cost of producing a desired power density at long range, which determines the maximum range of detectability of a transmitted signal. We derive general relations for cost-optimal aperture and power. For linear dependence of capital cost on transmitter power and antenna area, minimum capital cost occurs when the cost is equally divided between antenna gain and radiated power. For nonlinear power-law dependence, a similar simple division occurs. This is validated in cost data for many systems; industry uses this cost optimum as a rule of thumb. Costs of pulsed cost-efficient transmitters are estimated from these relations by using current cost parameters ($/W, $/sq m) as a basis. We show the scaling and give examples of such beacons. Galactic-scale beacons can be built for a few billion dollars with our present technology. Such beacons have narrow "searchlight" beams and short "dwell times" when the beacon would be seen by an alien observer in their sky. More-powerful beacons are more efficient and have economies of scale: cost scales only linearly with range R, not as R(exp 2), so number of stars radiated to increases as the square of cost. On a cost basis, they will likely transmit at higher microwave frequencies, -10 GHz. The natural corridor to broadcast is along the galactic radius or along the local spiral galactic arm we are in. A companion paper asks "If someone like us were to produce a beacon, how should we look for it?"

  8. Beach Advisory and Closing Online Notification (BEACON) system

    Data.gov (United States)

    U.S. Environmental Protection Agency — Beach Advisory and Closing Online Notification system (BEACON) is a colletion of state and local data reported to EPA about beach closings and advisories. BEACON is...

  9. A new class of SETI beacons that contain information (22-aug-2010)

    CERN Document Server

    Harp, G R; Blair, Samantha K; Arbunich, J; Backus, P R; Tarter, J C

    2012-01-01

    In the cm-wavelength range, an extraterrestrial electromagnetic narrow band (sine wave) beacon is an excellent choice to get alien attention across interstellar distances because 1) it is not strongly affected by interstellar / interplanetary dispersion or scattering, and 2) searching for narrowband signals is computationally efficient (scales as Ns log(Ns) where Ns = number of voltage samples). Here we consider a special case wideband signal where two or more delayed copies of the same signal are transmitted over the same frequency and bandwidth, with the result that ISM dispersion and scattering cancel out during the detection stage. Such a signal is both a good beacon (easy to find) and carries arbitrarily large information rate (limited only by the atmospheric transparency to about 10 GHz). The discovery process uses an autocorrelation algorithm, and we outline a compute scheme where the beacon discovery search can be accomplished with only 2x the processing of a conventional sine wave search, and discuss...

  10. iBeacon technology in the development of mobile applications

    OpenAIRE

    Zebec, Svit Timej

    2015-01-01

    iBeacon technology, made possible by BLE, enables mobile application developers to base their applications on proximity. We would like to know how proximity can be integrated in the development of mobile applications. In the thesis we take a deeper look at iBeacon technology where monitoring and ranging are examined and the differences between location and proximity explained. Available options used for the configuration of iBeacons are also presented. Then two existing iBeacon applications a...

  11. Getting Obstacle Avoidance Trajectory of Mobile Beacon for Localization

    OpenAIRE

    Huan-Qing CUI; Ying-Long WANG; Guo, Qiang; Wei, Nuo

    2010-01-01

    Localization is one of the most important technologies in wireless sensor network, and mobile beacon assisted localization is a promising localization method. The mobile beacon trajectory planning is a basic and important problem in these methods. There are many obstacles in the real world, which obstruct the moving of mobile beacon. This paper focuses on the obstacle avoidance trajectory planning scheme. After partitioning the deployment area with fixed cell decomposition, the beacon traject...

  12. Localization with a Mobile Beacon in Underwater Acoustic Sensor Networks

    OpenAIRE

    Sangho Lee; Kiseon Kim

    2012-01-01

    Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB). The mobile beacon periodically br...

  13. Distributed Beacon Drifting Detection for Localization in Unstable Environments

    OpenAIRE

    Ming Xia; Peiliang Sun; Xiaoyan Wang; Yan Jin; Qingzhang Chen

    2013-01-01

    Localization is a fundamental research issue in wireless sensor networks (WSNs). In most existing localization schemes, several beacons are used to determine the locations of sensor nodes. These localization mechanisms are frequently based on an assumption that the locations of beacons are known. Nevertheless, for many WSN systems deployed in unstable environments, beacons may be moved unexpectedly; that is, beacons are drifting, and their location information will no longer be reliable. As a...

  14. "Molecular beacon"-based fluorescent assay for selective detection of glutathione and cysteine.

    Science.gov (United States)

    Xu, Hui; Hepel, Maria

    2011-02-01

    We report on the development of a fluorescence turn-on "molecular beacon" probe for the detection of glutathione (GSH) and cysteine (Cys). The method is based on a competitive ligation of Hg(2+) ions by GSH/Cys and thymine-thymine (T-T) mismatches in a DNA strand of the self-hybridizing beacon strand. The assay relies on the distance-dependent optical properties of the fluorophore/quencher pair attached to the ends of the molecular beacon DNA strand. In a very selective coordination of Hg(2+) to GSH/Cys, the fluorophore/quencher distance increases concomitantly with the dehybridization and dissociation of the beacon stem T-Hg(2+)-T due to the extraction of Hg(2+) ions. This process results in switching the molecular beacon to the "on" state. The concentration range of the probe is 4-200 nM with the limit of detection (LOD) of 4.1 nM for GSH and 4.2 nM Cys. The probe tested satisfactorily against interference for a range of amino acids including sulfur-containing methionine.

  15. Analytically modelling the performance of piggybacking on beacons in VANETs

    NARCIS (Netherlands)

    Klein Wolterink, W.; Heijenk, G.; Berg, J.L. van den

    2012-01-01

    Piggybacking on beacons is a forwarding technique in vehicular ad-hoc networks (VANET) as a means to disseminate data. With this technique data is attached to and transmitted along with scheduled beacons. Nodes are assumed to beacon asynchronously. In this paper we present a first version of an anal

  16. 14 CFR 171.269 - Marker beacon performance requirements.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Marker beacon performance requirements. 171.269 Section 171.269 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Landing System (ISMLS) § 171.269 Marker beacon performance requirements. ISMLS marker beacon...

  17. 33 CFR 62.23 - Beacons and buoys.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Beacons and buoys. 62.23 Section... UNITED STATES AIDS TO NAVIGATION SYSTEM The U.S. Aids to Navigation System § 62.23 Beacons and buoys. (a... navigation. The primary components of the U.S. Aids to Navigation System are beacons and buoys. (b)...

  18. An aptamer beacon responsive to botulinum toxins.

    Science.gov (United States)

    Bruno, John G; Richarte, Alicia M; Carrillo, Maria P; Edge, Allison

    2012-01-15

    Sixty candidate DNA aptamers were developed against botulinum neurotoxin (BoNT) type A light chain (LC) from ten rounds of selection, resulting in several identical sequences. Secondary structures of the identical aptamers were compared to structures of previously reported BoNT A DNA aptamers. A series of ten candidate loop structures were selected from this comparison as potential binding pockets and aptamer beacons. These candidate beacons were synthesized with 5'-TYE 665 and 3'-Iowa Black quencher labels for comparison of fluorescence levels as a function of BoNT A LC concentration. Only three of the ten candidates exhibited any fluorescence response to increasing levels of BoNT A LC. However, of the two most responsive candidates, one represented a subset loop of the larger more intensely fluorescent double-looped structure, designated Beacon 10. This beacon yielded a lower limit of detection of 1 ng/mL in buffer using a spectrofluorometer and a portable handheld fluorometer, but also responded substantially to BoNT A, B, E holotoxins and heavy or light chain components even in a dilute soil suspension, but not in 50% human serum. Beacon 10 did not respond strongly to a variety of other divergent peptides, suggesting that it is relatively specific to the level of botulinum toxins and is only useful for environmental testing. Beacon 10 also shared short sequence segments with other published BoNT aptamer DNA sequences, suggesting that these may be points of physical contact between the aptamers and BoNTs.

  19. Cleavable DNA-protein hybrid molecular beacon: A novel efficient signal translator for sensitive fluorescence anisotropy bioassay.

    Science.gov (United States)

    Hu, Pan; Yang, Bin

    2016-01-15

    Due to its unique features such as high sensitivity, homogeneous format, and independence on fluorescent intensity, fluorescence anisotropy (FA) assay has become a hotspot of study in oligonucleotide-based bioassays. However, until now most FA probes require carefully customized structure designs, and thus are neither generalizable for different sensing systems nor effective to obtain sufficient signal response. To address this issue, a cleavable DNA-protein hybrid molecular beacon was successfully engineered for signal amplified FA bioassay, via combining the unique stable structure of molecular beacon and the large molecular mass of streptavidin. Compared with single DNA strand probe or conventional molecular beacon, the DNA-protein hybrid molecular beacon exhibited a much higher FA value, which was potential to obtain high signal-background ratio in sensing process. As proof-of-principle, this novel DNA-protein hybrid molecular beacon was further applied for FA bioassay using DNAzyme-Pb(2+) as a model sensing system. This FA assay approach could selectively detect as low as 0.5nM Pb(2+) in buffer solution, and also be successful for real samples analysis with good recovery values. Compatible with most of oligonucleotide probes' designs and enzyme-based signal amplification strategies, the molecular beacon can serve as a novel signal translator to expand the application prospect of FA technology in various bioassays.

  20. Cleavable DNA-protein hybrid molecular beacon: A novel efficient signal translator for sensitive fluorescence anisotropy bioassay.

    Science.gov (United States)

    Hu, Pan; Yang, Bin

    2016-01-15

    Due to its unique features such as high sensitivity, homogeneous format, and independence on fluorescent intensity, fluorescence anisotropy (FA) assay has become a hotspot of study in oligonucleotide-based bioassays. However, until now most FA probes require carefully customized structure designs, and thus are neither generalizable for different sensing systems nor effective to obtain sufficient signal response. To address this issue, a cleavable DNA-protein hybrid molecular beacon was successfully engineered for signal amplified FA bioassay, via combining the unique stable structure of molecular beacon and the large molecular mass of streptavidin. Compared with single DNA strand probe or conventional molecular beacon, the DNA-protein hybrid molecular beacon exhibited a much higher FA value, which was potential to obtain high signal-background ratio in sensing process. As proof-of-principle, this novel DNA-protein hybrid molecular beacon was further applied for FA bioassay using DNAzyme-Pb(2+) as a model sensing system. This FA assay approach could selectively detect as low as 0.5nM Pb(2+) in buffer solution, and also be successful for real samples analysis with good recovery values. Compatible with most of oligonucleotide probes' designs and enzyme-based signal amplification strategies, the molecular beacon can serve as a novel signal translator to expand the application prospect of FA technology in various bioassays. PMID:26592607

  1. Localization with a Mobile Beacon in Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sangho Lee

    2012-04-01

    Full Text Available Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB. The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node’s location and then the node’s location is determined through the weighted mean of all the potential locations with the weights computed based on residuals.

  2. Localization with a mobile beacon in underwater acoustic sensor networks.

    Science.gov (United States)

    Lee, Sangho; Kim, Kiseon

    2012-01-01

    Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB). The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node's location and then the node's location is determined through the weighted mean of all the potential locations with the weights computed based on residuals.

  3. iBeacon technology in the development of mobile applications

    OpenAIRE

    Zebec, Svit Timej

    2015-01-01

    iBeacon technology, made possible by BLE, enables mobile application developers to base their applications on proximity. We would like to know how proximity can be integrated in the development of mobile applications. In the thesis we take a deeper look at iBeacon technology where monitoring and ranging are examined and the differences between location and proximity explained. Available options used for the configuration of iBeacons are also presented. Then two existing iBea...

  4. A Composite Beacon Initialization for EKF Range-Only SLAM

    OpenAIRE

    Génevé, Lionel; Kermorgant, Olivier; Laroche, Edouard

    2015-01-01

    Accurately localize a mobile vehicle with an easy and quickly deployable system can be very useful for many applications. Herein we present an EKF-SLAM algorithm which allows using radio frequency (RF) beacons without any prior knowledge of their location. As RF beacons provide only range information, recovering their positions is not an easy task. For this range-only SLAM case, a new procedure to instantiate the beacons in the filter is proposed. The method uses two range measurements from d...

  5. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Directory of Open Access Journals (Sweden)

    Yuanfu Mo

    Full Text Available In a vehicular ad hoc network (VANET, the periodic exchange of single-hop status information broadcasts (beacon frames produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  6. Beacon-Based Service Publishing Framework in Multiservice Wi-Fi Hotspots

    Directory of Open Access Journals (Sweden)

    Di Sorte Dario

    2007-01-01

    Full Text Available In an expected future multiaccess and multiservice IEEE 802.11 environment, the problem of providing users with useful service-related information to support a correct rapid network selection is expected to become a very important issue. A feasible short-term 802.11-tailored working solution, compliant with existing equipment, is to publish service information encoded within the SSID information element within beacon frames. This makes it possible for an operator to implement service publishing in 802.11 networks while waiting for a standardized mechanism. Also, this straightforward approach has allowed us to evaluate experimentally the performance of a beacon-based service publishing solution. In fact, the main focus of the paper is indeed to present a quantitative comparison of service discovery times between the legacy scenario, where the user is forced to associate and authenticate with a network point of access to check its service offer, and the enhanced scenario where the set of service-related information is broadcasted within beacons. These discovery times are obtained by processing the results of a measurement campaign performed in a multiaccess/service 802.11 environment. This analysis confirms the effectiveness of the beacon-based approach. We also show that the cost in terms of wireless bandwidth consumption of such solution is low.

  7. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Science.gov (United States)

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  8. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Science.gov (United States)

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network. PMID:26571042

  9. Validation of the Calypso Surface Beacon Transponder.

    Science.gov (United States)

    Belanger, Maxwell; Saleh, Ziad; Volpe, Tom; Margiasso, Rich; Li, Xiang; Chan, Maria; Zhu, Xiaofeng; Tang, Xiaoli

    2016-07-08

    Calypso L-shaped Surface Beacon transponder has recently become available for clinical applications. We herein conduct studies to validate the Surface Beacon transponder in terms of stability, reproducibility, orientation sensitivity, cycle rate dependence, and respiratory waveform tracking accuracy. The Surface Beacon was placed on a Quasar respiratory phantom and positioned at the isocenter with its two arms aligned with the lasers. Breathing waveforms were simulated, and the motion of the transponder was tracked. Stability and drift analysis: sinusoidal waveforms (200 cycles) were produced, and the amplitudes of phases 0% (inhale) and 50% (exhale) were recorded at each breathing cycle. The mean and standard deviation (SD) of the amplitudes were calculated. Linear least-squares fitting was performed to access the possible amplitude drift over the breathing cycles. Reproducibility: similar setting to stability and drift analysis, and the phantom generated 100 cycles of the sinusoidal waveform per run. The Calypso system's was re-setup for each run. Recorded amplitude and SD of 0% and 50% phase were compared between runs to assess contribution of Calypso electromagnetic array setup variation. Beacon orientation sensitivity: the Calypso tracks sinusoidal phantom motion with a defined angular offset of the beacon to assess its effect on SD and peak-to-peak amplitude. Rate dependence: sinusoidal motion was generated at cycle rates of 1 Hz, .33 Hz, and .2 Hz. Peak-to-peak displacement and SDs were assessed. Respiratory waveform tracking accuracy: the phantom reproduced recorded breathing cycles (by volunteers and patients) were tracked by the Calypso system. Deviation in tracking position from produced waveform was used to calculate SD throughout entire breathing cycle. Stability and drift analysis: Mean amplitude ± SD of phase 0% or 50% were 20.01 ± 0.04 mm and -19.65 ± 0.08 mm, respectively. No clinically significant drift was detected with drift measured as 5.1

  10. Validation of the Calypso Surface Beacon Transponder.

    Science.gov (United States)

    Belanger, Maxwell; Saleh, Ziad; Volpe, Tom; Margiasso, Rich; Li, Xiang; Chan, Maria; Zhu, Xiaofeng; Tang, Xiaoli

    2016-01-01

    Calypso L-shaped Surface Beacon transponder has recently become available for clinical applications. We herein conduct studies to validate the Surface Beacon transponder in terms of stability, reproducibility, orientation sensitivity, cycle rate dependence, and respiratory waveform tracking accuracy. The Surface Beacon was placed on a Quasar respiratory phantom and positioned at the isocenter with its two arms aligned with the lasers. Breathing waveforms were simulated, and the motion of the transponder was tracked. Stability and drift analysis: sinusoidal waveforms (200 cycles) were produced, and the amplitudes of phases 0% (inhale) and 50% (exhale) were recorded at each breathing cycle. The mean and standard deviation (SD) of the amplitudes were calculated. Linear least-squares fitting was performed to access the possible amplitude drift over the breathing cycles. Reproducibility: similar setting to stability and drift analysis, and the phantom generated 100 cycles of the sinusoidal waveform per run. The Calypso system's was re-setup for each run. Recorded amplitude and SD of 0% and 50% phase were compared between runs to assess contribution of Calypso electromagnetic array setup variation. Beacon orientation sensitivity: the Calypso tracks sinusoidal phantom motion with a defined angular offset of the beacon to assess its effect on SD and peak-to-peak amplitude. Rate dependence: sinusoidal motion was generated at cycle rates of 1 Hz, .33 Hz, and .2 Hz. Peak-to-peak displacement and SDs were assessed. Respiratory waveform tracking accuracy: the phantom reproduced recorded breathing cycles (by volunteers and patients) were tracked by the Calypso system. Deviation in tracking position from produced waveform was used to calculate SD throughout entire breathing cycle. Stability and drift analysis: Mean amplitude ± SD of phase 0% or 50% were 20.01 ± 0.04 mm and -19.65 ± 0.08 mm, respectively. No clinically significant drift was detected with drift measured as 5.1

  11. Development of a universal RNA beacon for exogenous gene detection.

    Science.gov (United States)

    Guo, Yuanjian; Lu, Zhongju; Cohen, Ira Stephen; Scarlata, Suzanne

    2015-05-01

    Stem cell therapy requires a nontoxic and high-throughput method to achieve a pure cell population to prevent teratomas that can occur if even one cell in the implant has not been transformed. A promising method to detect and separate cells expressing a particular gene is RNA beacon technology. However, developing a successful, specific beacon to a particular transfected gene can take months to develop and in some cases is impossible. Here, we report on an off-the-shelf universal beacon that decreases the time and cost of applying beacon technology to select any living cell population transfected with an exogenous gene.

  12. Molecular Engineering of DNA: Molecular Beacons

    OpenAIRE

    Wang, Kemin; Tang, Zhiwen; Yang, Chaoyong James; Kim, Youngmi; Fang, Xiaohong; Li, Wei; Wu, Yanrong; Medley, Colin D.; Cao, Zehui; Jun LI; Colon, Patrick; Lin, Hui; Tan, Weihong

    2009-01-01

    Molecular beacons (MBs) are specifically designed DNA hairpin structures that are widely used as fluorescent probes. Applications of MBs range from genetic screening, biosensor development, biochip construction, and the detection of single-nucleotide polymorphisms to mRNA monitoring in living cells. The inherent signal-transduction mechanism of MBs enables the analysis of target oligonucleotides without the separation of unbound probes. The MB stem–loop structure holds the fluorescence-donor ...

  13. Experience with the BEACON core monitoring system

    International Nuclear Information System (INIS)

    The BEACON operational core support system was developed for use in pressurized water reactors to provide an integrated system to perform reactor core monitoring, core measurement reduction, core analysis and follow, and core predictions. It is based on the very fast and accurate three-dimensional SPNOVA nodal program. The experience to date has shown the importance of an accurate integrated system. The benefits accrued are greater for the total system than the benefits that are possible separately

  14. Monte Carlo simulation of a gas measurement beacon: computation and validation, ASGA/VGM beacon

    International Nuclear Information System (INIS)

    The author reports a Monte Carlo simulation of a gas measurement sensor (ASGA or Ventilation Gas Monitor) used to monitor and detect radioactivity in the ventilation of the CERN's LHC (Large Hadron Collider). He recalls the performance required for these beacons, and the different factors governing their detection threshold. He discusses the possibilities offered by the GEANT4 code to model and simulation the beacon physics, and to generate events. Results are obtained in terms of spectrum of deposited energy. The author reports the sensitivity determination

  15. How can we distinguish transient pulsars from SETI beacons?

    CERN Document Server

    Benford, James

    2010-01-01

    How would observers differentiate Beacons from pulsars or other exotic sources, in light of likely Beacon observables? Bandwidth, pulse width and frequency may be distinguishing features. Such transients could be evidence of civilizations slightly higher than ourselves on the Kardashev scale.

  16. Beacons In Brief. P/PV In Brief. Issue 2

    Science.gov (United States)

    Blank, Susan; Farley, Chelsea

    2004-01-01

    This second issue in P/PV's "In Brief" series focuses on the San Francisco Beacon Initiative and P/PV's recently released evaluation results. The Beacon Initiative established after-school programs in eight public schools in low-income San Francisco neighborhoods. P/PV's 36-month evaluation examined key developmental and academic outcomes.…

  17. Getting Obstacle Avoidance Trajectory of Mobile Beacon for Localization

    Directory of Open Access Journals (Sweden)

    Huan-Qing CUI

    2010-11-01

    Full Text Available Localization is one of the most important technologies in wireless sensor network, and mobile beacon assisted localization is a promising localization method. The mobile beacon trajectory planning is a basic and important problem in these methods. There are many obstacles in the real world, which obstruct the moving of mobile beacon. This paper focuses on the obstacle avoidance trajectory planning scheme. After partitioning the deployment area with fixed cell decomposition, the beacon trajectory are divided into global and local trajectory. The approximate shortest global trajectory is obtained by depth-first search, greedy strategy method and ant colony algorithm, while local trajectory is any existing trajectories. Simulation results show that this method can avoid obstacles in the network deployment area, and the smaller cell size leads to longer beacon trajectory and more localizable sensor nodes.

  18. Recent progress in satellite radio beacon studies with particular emphasis on the ATS-6 radio beacon experiment

    International Nuclear Information System (INIS)

    In May 1974 a new era in satellite radio beacon studies of the ionosphere opened with the ATS-6 Radio Beacon Experiment. The history of radio beacon studies up to that time is reviewed briefly and the particular features of the ATS-6 beacon are discussed together with the basic theory required to interpret the measurements. The main emphasis is on the ATS-6 beacon experiment but other beacon data are discussed which provide the necessary background. The diurnal and seasonal variations of the total electron content and the plasmaspheric content are presented for the U.S.A. and Europe. In winter the plasmaspheric content over the Western Hemisphere maximizes at night while in Europe and the Pacific it appears to peak near noon. This is thought to be caused by flow of plasma from the local and conjugate ionospheres. Night maxima of total electron content are found showing that they do not arise from depletions of the plasmaspheric content. The plasmaspheric content is highly sensitive to solar-terrestrial disturbance, it reaches a minimum on the third day of a storm and may take between 10 and 20 days of partial filling and emptying to recover. Travelling disturbances in U.S.A., Europe, and India show similarities of speeds but not of direction. Beacon observations of micropulsations in total content, tropospheric fluctuations and Fresnel diffraction by intense ionospheric irregularities are discussed together with radio wave scintillations and some applications of beacon radio data to communications and navigation. (orig.)

  19. Determining Locations by Use of Networks of Passive Beacons

    Science.gov (United States)

    Okino, Clayton; Gray, Andrew; Jennings, Esther

    2009-01-01

    Networks of passive radio beacons spanning moderate-sized terrain areas have been proposed to aid navigation of small robotic aircraft that would be used to explore Saturn s moon Titan. Such networks could also be used on Earth to aid navigation of robotic aircraft, land vehicles, or vessels engaged in exploration or reconnaissance in situations or locations (e.g., underwater locations) in which Global Positioning System (GPS) signals are unreliable or unavailable. Prior to use, it would be necessary to pre-position the beacons at known locations that would be determined by use of one or more precise independent global navigation system(s). Thereafter, while navigating over the area spanned by a given network of passive beacons, an exploratory robot would use the beacons to determine its position precisely relative to the known beacon positions (see figure). If it were necessary for the robot to explore multiple, separated terrain areas spanned by different networks of beacons, the robot could use a long-haul, relatively coarse global navigation system for the lower-precision position determination needed during transit between such areas. The proposed method of precise determination of position of an exploratory robot relative to the positions of passive radio beacons is based partly on the principles of radar and partly on the principles of radio-frequency identification (RFID) tags. The robot would transmit radar-like signals that would be modified and reflected by the passive beacons. The distance to each beacon would be determined from the roundtrip propagation time and/or round-trip phase shift of the signal returning from that beacon. Signals returned from different beacons could be distinguished by means of their RFID characteristics. Alternatively or in addition, the antenna of each beacon could be designed to radiate in a unique pattern that could be identified by the navigation system. Also, alternatively or in addition, sets of identical beacons could

  20. Molecular beacon – tool for real time studying gene activity in stem cells.

    OpenAIRE

    Ilieva, Mirolyuba; Dufva, Martin

    2012-01-01

    Cells respond to their internal genetic programs and external stimuli by modulating the synthesis of specific mRNAs. Direct observation of mRNA expression in living cells can provide valuable information with regards to understanding fundamental processes such cell differentiation, regeneration and cancerogenesis. Molecular beacon technology is based on fluorescence resonance energy transfer (FRET) and the complementary pairing principles. These fluorescent molecular probes are highly specifi...

  1. Position Prediction Based Frequency Control of Beacons in Vehicular Ad Hoc Networks

    OpenAIRE

    Jizhao Liu; Quan Wang

    2015-01-01

    In VANETs, frequent beacon broadcasting can lead to high bandwidth consumption and channel congestion. In this paper, a position prediction based beacon approach is proposed to reduce beacon frequency and decrease bandwidth consumption. Vehicles track their neighbors using the predicted position instead of using periodic beacon broadcasting. Only when the prediction error is higher than a predefined tolerance will a beacon broadcasting be triggered. For improving the prediction accuracy, we c...

  2. Research on IEEE 802.22.1 Beacon Networks Application%IEEE 802.22.1信标网络应用研究

    Institute of Scientific and Technical Information of China (English)

    杨大全

    2012-01-01

    Several IEEE 802.22.1 beacon devices are used to build beacon network by self-organization. IEEE 802.22.1 beacon protocol is introduced, and the decision strategies of beacon networks in the process of establishing and maintenance are discussed. IEEE 802.22.1 beacon networks sensing and information detection in WRAN device are introduced. The maximum latency before scheduling a quiet period that will ensure to capture the full information of the beacon network is given.%多个IEEE 802.22.1信标设备将自组织成信标网络.介绍了IEEE 802.22.1标准中定义的自组织方案;讨论了信标网络建立与维持过程中的判决策略;介绍了无线区域网络(WRAN)设备对IEEE 802.22.1信标网络的识别与信息获取机制;给出了确保实现对信标网络信息解析所需要安排的最大时延.

  3. Diagnosis of Neisseria gonorrhoeae Using Molecular Beacon

    Directory of Open Access Journals (Sweden)

    Divya Sachdev

    2015-01-01

    Full Text Available Neisseria gonorrhoeae is an important sexually transmitted diseases (STD causing pathogen worldwide. Due to absence of an affordable diagnostic assay, routine screening of gonococcal infection becomes impossible in developing countries where infection rates are maximum. Treatment is given on the basis of symptoms alone which leads to spread of infection. Thus, development of a rapid, sensitive, specific, and PCR based visual diagnostic assay suitable for developing countries, required for better disease management, is aimed at in present study. Endocervical swabs were collected from patients visiting gynecology department of various hospitals in Delhi. In-house PCR based assay was developed and modified to visual assay using molecular beacon for end-point detection. It was evaluated against Roche AMPLICOR NG kit and rmp gene. Specificity of beacon was confirmed by competition experiments. Diagnostic test was 98.21% specific and 99.59% sensitive whereas negative and positive predicted value were 99.40% and 98.78%, respectively. We also observed that twice the concentration (2X of premix was stable at 4°C for 4 months and dry swab samples gave concordant results with that of wet swabs. These features make the test best suitable for routine diagnosis of genital infections in developing countries.

  4. Ultrasensitive monitoring of ribozyme cleavage product using molecular-beacon-ligation system

    Institute of Scientific and Technical Information of China (English)

    MENG XiangXian; TANG ZhiWen; WANG KeMin; TAN WeiHong; YANG XiaoHai; LI Jun; GUO QiuPing

    2007-01-01

    This paper reports a new approach to detect ribozyme cleavage product based on the molecular- beacon-ligation system. The molecular beacon, designed in such a way that one-half of its loop is complementary to ribozyme cleavage product, is used to monitor ligation process of RNA/DNA complex in a homogeneous solution and to convert directly cleavage product information into fluorescence signal. The method need not label ribozyme and ribozyme substrate, which is fast, simple and ultrasensitive for detection of cleavage product. Detection limit of the assay is 0.05 nmol/L. The cleavage product of hammerhead ribozyme against hepatitis C virus RNA (HCV-RNA) was detected perfectly based on this assay. Owing to its ultrasensitivity, excellent specificity, convenience and fidelity, this method might hold out great promise in ribozyme reaction and ribozyme gene therapy.

  5. BEACON TSM application system to the operation of PWR reactors

    International Nuclear Information System (INIS)

    BEACON-TSM is an advanced core monitoring system for PWR reactor cores, and also offers the possibility to perform a wide range of predictive calculation in support of reactor operation. BEACON-TSM is presently installed and licensed in the 5 Spanish PWR reactors of standard Westinghouse design. the purpose of this paper is to describe the features of this software system and to show the advantages obtainable by a nuclear power plant from its use. To illustrate the capabilities and benefits of BEACON-TSM two real case reactor operating situations are presented. (Author)

  6. Beacon-S TM: Non-uniform attenuation correction for SPECT imaging. The new medium-energy transmission device for AXIS and IRIX

    International Nuclear Information System (INIS)

    The paper presents new medium-energy transmission device for SPECT imaging. Beacon-S includes a 356-keV medium energy 133Ba source with a 10.54-year half-life. Beacon-S provide high-resolution and high-contrast transmission scans. The higher energy of the gamma substantially improves the transmission contrast for larger patients by virtue of better penetration through the body

  7. Optical telecommunications: performance of the qualification model SILEX beacon

    Science.gov (United States)

    Renard, Michel; Dobie, Paul J.; Gollier, Jacques; Heinrichs, Theo; Woszczyk, Pawel; Sobeczko, Andre

    1995-04-01

    The Beacon is a powerful non-coherent CW infra-red laser source which is developed under the Semi-conductor Inter-satellite Link Experiment (SILEX). It will provide a high divergence beam used during the first tracking acquisition sequence of the Spot 4/Artemis optical communication link. The Beacon uses high efficiency anamorphic couplers to deliver output from 19 laser diodes into a single multi-mode Mixing Fiber, the exit of which is integrated at the focal plane of a collimator. Beacon output is maintained at the required level during unit life using an Optical Monitoring System and a Beacon output Tele-Command. The Engineering Qualification Model is now complete and overall performance with respect to the SILEX requirements is presented.

  8. Modeling DNA beacons at the mesoscopic scale

    CERN Document Server

    Errami, Jalal; Theodorakopoulos, Nikos

    2007-01-01

    We report model calculations on DNA single strands which describe the equilibrium dynamics and kinetics of hairpin formation and melting. Modeling is at the level of single bases. Strand rigidity is described in terms of simple polymer models; alternative calculations performed using the freely rotating chain and the discrete Kratky-Porod models are reported. Stem formation is modeled according to the Peyrard-Bishop-Dauxois Hamiltonian. The kinetics of opening and closing is described in terms of a diffusion-controlled motion in an effective free energy landscape. Melting profiles, dependence of melting temperature on loop length, and kinetic time scales are in semiquantitative agreement with experimental data obtained from fluorescent DNA beacons forming poly(T) loops. Variation in strand rigidity is not sufficient to account for the large activation enthalpy of closing and the strong loop length dependence observed in hairpins forming poly(A) loops. Implications for modeling single strands of DNA or RNA are...

  9. Optical telecommunications: expected performance of the beacon

    Science.gov (United States)

    Renard, Michel; Gollier, Jacques; Dobie, Paul J.; Heinrichs, Theo; Sobeczko, Andre

    1994-09-01

    The beacon is a powerful non-coherent CW laser source which is developed in the frame of the Semi-conductor Inter-satellite Link Experiment (SILEX). Its functionality is to provide a high divergence beam during the first tracking sequence. It is made up of 19 laser diodes coupled into one multi-mode fiber, the exit face of that fiber being integrated at the focal plane of a collimator. A breadboarding phase has been conducted at the beginning of the phase C/D in order to demonstrate that the requirement of 8 KW/Sr within a divergence of 11.75 mRd will be achieved. That phase is now completed and the overall breadboard performance is discussed in this paper with respect to the SILEX requirements.

  10. A Search for New Physics with the BEACON Mission

    OpenAIRE

    Turyshev, Slava G.; Lane, Benjamin; Shao, Michael; Girerd, Andre

    2008-01-01

    The primary objective of the Beyond Einstein Advanced Coherent Optical Network (BEACON) mission is a search for new physics beyond general relativity by measuring the curvature of relativistic space-time around Earth. This curvature is characterized by the Eddington parameter \\gamma -- the most fundamental relativistic gravity parameter and a direct measure for the presence of new physical interactions. BEACON will achieve an accuracy of 1 x 10^{-9} in measuring the parameter \\gamma, thereby ...

  11. Range free Localization Mechanism using Beacon node Range Level

    OpenAIRE

    Shweta Sirothia; Rakesh Tripathi

    2012-01-01

    The mechanism for finding the position of sensor node is crucialfor many sensor network applications. Most sensor networkswhich can tolerate coarse accuracy look range free localizationmechanism as its solution. We have proposed a novel algorithmwhere beacon nodes are randomly distributed and sensor nodesestimates the beacon nodes at different levels according tosignal strength. We determine the location of sensor nodes byusing this information. We assume the communication range ofsensor and ...

  12. A heuristic evaluation of the Facebook's advertising tool beacon

    OpenAIRE

    Jamal, A.; Cole, M.

    2009-01-01

    Interface usability is critical to the successful adoption of information systems. The aim of this study is to evaluate interface of Facebook's advertising tool Beacon by using privacy heuristics [4]. Beacon represents an interesting case study because of the negative media and user backlash it received. The findings of heuristic evaluation suggest violation of privacy heuristics [4]. Here, analysis identified concerns about user choice and consent, integrity and security of data, and awarene...

  13. Station Keeping through Beacon-referenced Cyclic Pursuit

    OpenAIRE

    Galloway, Kevin S.; Dey, Biswadip

    2015-01-01

    This paper investigates a modification of cyclic constant bearing (CB) pursuit in a multi-agent system in which each agent pays attention to a neighbor and a beacon. The problem admits shape equilibria with collective circling about the beacon, with the circling radius and angular separation of agents determined by choice of parameters in the feedback law. Stability of circling shape equilibria is shown for a 2-agent system, and the results are demonstrated on a collective of mobile robots tr...

  14. Smartphone-Based Indoor Localization with Bluetooth Low Energy Beacons

    OpenAIRE

    Yuan Zhuang; Jun Yang; You Li; Longning Qi; Naser El-Sheimy

    2016-01-01

    Indoor wireless localization using Bluetooth Low Energy (BLE) beacons has attracted considerable attention after the release of the BLE protocol. In this paper, we propose an algorithm that uses the combination of channel-separate polynomial regression model (PRM), channel-separate fingerprinting (FP), outlier detection and extended Kalman filtering (EKF) for smartphone-based indoor localization with BLE beacons. The proposed algorithm uses FP and PRM to estimate the target’s location and the...

  15. Magnetic resonance beacon to detect intracellular microRNA during neurogenesis.

    Science.gov (United States)

    Lee, Jonghwan; Jin, Yeon A; Ko, Hae Young; Lee, Yong Seung; Heo, Hyejung; Cho, Sujeong; Kim, Soonhag

    2015-02-01

    Magnetic resonance imaging (MRI) offers great spatial resolution for viewing deep tissues and anatomy. We developed a self-assembling signal-on magnetic fluorescence nanoparticle to visualize intracellular microRNAs (miRNAs or miRs) during neurogenesis using MRI. The self-assembling nanoparticle (miR124a MR beacon) was aggregated by the incubation of three different oligonucleotides: a 3' adaptor, a 5' adaptor, and a linker containing miR124a-binding sequences. The T2-weighted magnetic resonance (MR) signal of the self-assembled nanoparticle was quenched when miR124a was absent from test tubes or was minimally expressed in cells and tissues. When miR124a was present in test tubes or highly expressed in vitro and in vivo during P19 cell neurogenesis, it hybridized with the miR124a MR beacon, causing the linker to detach, resulting in increased signal-on MRI intensity. This MR beacon can be used as a new imaging probe to monitor the miRNA-mediated regulation of cellular processes.

  16. Beacon-Colss core monitoring system application and benefits

    International Nuclear Information System (INIS)

    Westinghouse and KNFC are creating an upgraded core monitoring system by merging the BEACON system (best estimate analyzer for core operation-nuclear) and COLSS (core operating limit supervisory system) into an integrated product. Although both BEACON and COLSS are core monitoring systems that have been in operation at many plants for a number of years, they each have some features and capabilities that are not in the other. Therefore it has been decided to incorporate portions of COLSS into the beacon system to create an optional level to support core monitoring applications on selected combustion engineering (C-E) designed plants. This optional level in the beacon system will be called BEACON-COLSS and will allow the beacon system to monitor the LCO's and Tech Spec limits at CE plants that currently use COLSS. This paper will present the structure of the new core monitoring system and the benefits it achieves for current COLSS plants, i.e., CE plants in the US and KSNP (Korean standard nuclear power plant). (authors)

  17. Optical telecommunications: performance of the protoflight model SILEX beacon

    Science.gov (United States)

    Renard, Michel; Dobie, Paul J.; Grodent, C.; Woszczyk, Pawel; Sobeczko, Andre

    1996-04-01

    The beacon is a powerful non-coherent cw infra-red laser source which will provide a high divergence beam used during the first tracking acquisition sequence of the Spot 4/Artemis optical communication link. The beacon uses high efficiency anamorphic couplers to deliver output from 19 laser diodes into a single multi-mode mixing fiber, the exit of which is integrated at the focal plane of a collimator. Beacon output is maintained at the required level (nominally 8 KW/Sr) during unit life using an optical monitoring system and a beacon output tele-command. Following successful environmental testing, the proto-flight model (PFM) has recently been delivered ready for integration onto the SILEX terminal. This paper describes the overall performance of the PFM beacon with respect to SILEX requirements. An improved beacon using 1.2 W laser diodes which will be capable of delivering up to 17 KW/Sr is currently under construction. An analysis of the design aspects to be considered when using high power laser diodes in this type of application is presented. Finally, a brief summary is given of SPACEBEL activities associated with high power and more compact optical communication units for future missions.

  18. A Combinatorial Bound for Beacon-based Routing in Orthogonal Polygons

    OpenAIRE

    Shermer, Thomas C.

    2015-01-01

    Beacon attraction is a movement system whereby a robot (modeled as a point in 2D) moves in a free space so as to always locally minimize its Euclidean distance to an activated beacon (which is also a point). This results in the robot moving directly towards the beacon when it can, and otherwise sliding along the edge of an obstacle. When a robot can reach the activated beacon by this method, we say that the beacon attracts the robot. A beacon routing from $p$ to $q$ is a sequence $b_1, b_2,$ ...

  19. Secure DV-Hop Algorithm Against Malicious Beacon Nodes%抵抗恶意信标的安全优化DV-Hop算法

    Institute of Scientific and Technical Information of China (English)

    黄晨钟; 许力; 叶阿勇; 钟进发

    2011-01-01

    信标节点在无线传感器网络定位算法中起着关键作用,然而信标节点的安全常常被忽视.针对恶意信标节点发送虚假位置信息这种较常见且破坏性较强的攻击方式,在DV-Hop定位算法的基础上提出了一种抵抗恶意信标的安全Dv-Hop定位算法.该算法利用信标之间的距离约束来隔离恶意信标节点,同时采用多信标校正值权衡的策略克服了信标比例下降与残余恶意信标对定位结果带来的不利影响,提高定位的准确性和安全性.%The beacon nodes play a key role in the process of unknown nodes' localization in wireless sensor networks' localization algorithms. However, the security of beacon nodes is often overlooked. A secure and optimal DV-Hop localization algorithm is proposed against malicious beacon nodes which send false location information in this paper. The proposed algorithm isolates malicious beacon nodes by the scheme of beacon-distance constraint and overcomes negative factor which is caused by the decline of beacon nodes' ratio and remaining malicious beacon nodes by the scheme of multi-correction balance. It improves the correction and security performance of localization algorithm.

  20. Study of Probabilistic Worst Case Inter-Beacon Delays Under Realistic Vehicular Mobility Conditions

    OpenAIRE

    Mouradian, Alexandre

    2015-01-01

    International audience Road safety applications are one of the main incentives to deploy vehicular networks. These applications rely on periodic message exchange among vehicles (known as beaconing). The beacon messages contain information about the environment which is used to perceive dangerous situations and alert the drivers. The inter-beacon delay is the time between two consecutive beacons received from a car. It is an essential parameter because, if this delay exceeds the application...

  1. Gold nanoparticle-based beacon to detect STAT5b mRNA expression in living cells: a case optimized by bioinformatics screen.

    Science.gov (United States)

    Deng, Dawei; Li, Yang; Xue, Jianpeng; Wang, Jie; Ai, Guanhua; Li, Xin; Gu, Yueqing

    2015-01-01

    Messenger RNA (mRNA), a single-strand ribonucleic acid with functional gene information is usually abnormally expressed in cancer cells and has become a promising biomarker for the study of tumor progress. Hairpin DNA-coated gold nanoparticle (hDAuNP) beacon containing a bare gold nanoparticle (AuNP) as fluorescence quencher and thiol-terminated fluorescently labeled stem-loop-stem oligonucleotide sequences attached by Au-S bond is currently a new nanoscale biodiagnostic platform capable of mRNA detection, in which the design of the loop region sequence is crucial for hybridizing with the target mRNA. Hence, in this study, to improve the sensitivity and selectivity of hDAuNP beacon simultaneously, the loop region of hairpin DNA was screened by bioinformatics strategy. Here, signal transducer and activator of transcription 5b (STAT5b) mRNA was selected and used as a practical example. The results from the combined characterizations using optical techniques, flow cytometry assay, and cell microscopic imaging showed that after optimization, the as-prepared hDAuNP beacon had higher selectivity and sensitivity for the detection of STAT5b mRNA in living cells, as compared with our previous beacon. Thus, the bioinformatics method may be a promising new strategy for assisting in the designing of the hDAuNP beacon, extending its application in the detection of mRNA expression and the resultant mRNA-based biological processes and disease pathogenesis.

  2. The use of BEACON monitoring in plant power uprates

    International Nuclear Information System (INIS)

    BEACON is the core support software technology that provides Utilities with continuous 3-D core power distribution monitoring, operational analysis capability, and operations support capability. BEACON monitoring delivers quantifiable plant margins for both reload design and plant operations improvement. When linked to Plant Power Upratings, BEACON permits an improvement in fuel cycle economics through higher peaking factors, higher power levels and higher discharge burnups. Operational flexibility of Uprated Plants is enhanced through elimination of axial power shape and core power tilt specifications. Also, the number of flux maps for these plants is reduced and local power is monitored continuously, permitting faster power escalation. Integrated 3-D power distribution analysis capabilities provide core designers with historical margin data that permits a reduction in core follow requirements as well as reduced curve book data related scope. Examples of specific Uprated Plant applications will be discussed. In anticipation of future needs of Uprated Plants, plans to integrate the technology of BEACON with COLSS are being executed. Finally, the capability to monitor Crud Induced Power Shift (axial offset) is also planned for incorporation into BEACON in the near future and will be discussed

  3. Beacon-Less Geographic Routing in Real Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    Juan A. Sánchez; Rafael Marín-Pérez; Pedro M. Ruiz

    2008-01-01

    Geographic Routing (GR) algorithms require nodes to periodically transmit HELLO messages to allow neigh-bors to know their positions (beaconing mechanism). Beacon-less routing algorithms have recently been proposed to reduce the control overheads due to these messages. However, existing beacon-less algorithms have not considered realistic physical layers. Therefore, those algorithms cannot work properly in realistic scenarios. In this paper we present a new beacon-less routing protocol called BOSS. Its design is based on the conclusions of our open-field experiments using Tmote-sky sensors. BOSS is adapted to error-prone networks and incorporates a new mechanism to reduce collisions and duplicate messages produced during the selection of the next forwarder node. We compare BOSS with Beacon-Less Routing (BLR)and Contention-Based Forwarding (CBF) algorithms through extensive simulations. The results show that our scheme is able to achieve almost perfect packet delivery ratio (like BLR) while having a low bandwidth consumption (even lower than CBF). Additionally, we carried out an empirical evaluation in a real testbed that shows the correctness of our simulation results.

  4. 14 CFR 171.321 - DME and marker beacon performance requirements.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false DME and marker beacon performance... (MLS) § 171.321 DME and marker beacon performance requirements. (a) The DME equipment must meet the..._regulations/ibr_locations.html. (b) MLS marker beacon equipment must meet the performance...

  5. 76 FR 65216 - Beacon Medical Services, LLC, Aurora, CO; Notice of Negative Determination Regarding Application...

    Science.gov (United States)

    2011-10-20

    ... (76 FR 40401). The workers of Beacon Medical Services are engaged in activities related ] to the... Employment and Training Administration Beacon Medical Services, LLC, Aurora, CO; Notice of Negative... apply for Trade Adjustment Assistance (TAA) applicable to workers and former workers of Beacon...

  6. 33 CFR 149.580 - What are the requirements for a radar beacon?

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false What are the requirements for a radar beacon? 149.580 Section 149.580 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Navigation Miscellaneous § 149.580 What are the requirements for a radar beacon? (a) A radar beacon...

  7. 76 FR 17625 - Proposed Information Collection; Comment Request; Emergency Beacon Registrations

    Science.gov (United States)

    2011-03-30

    ... Beacon Registrations AGENCY: National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION... ships, aircraft, or individuals in distress if they are equipped with an emergency radio beacon. Persons purchasing a digital distress beacon, operating in the frequency range of 406.000 to 406.100 MHz,...

  8. 33 CFR 149.535 - What are the requirements for rotating beacons on platforms?

    Science.gov (United States)

    2010-07-01

    ... rotating beacons on platforms? 149.535 Section 149.535 Navigation and Navigable Waters COAST GUARD... EQUIPMENT Aids to Navigation Lights on Platforms § 149.535 What are the requirements for rotating beacons on... rotating beacon that distinguishes the deepwater port from other surrounding offshore structures....

  9. A Place To Grow: Evaluation of the New York City Beacons. Summary Report.

    Science.gov (United States)

    Warren, Constancia; Feist, Michelle; Nevarez, Nancy

    This study examined six Beacon centers, which are community centers located in public school buildings that offer a range of activities and services to participants of all ages, before and after school, in the evenings, and on weekends. Individual Beacons are managed by community-based organizations. The study examined how the Beacons provided…

  10. A Search for New Physics with the BEACON Mission

    CERN Document Server

    Turyshev, Slava G; Shao, Michael; Girerd, Andre

    2008-01-01

    The primary objective of the Beyond Einstein Advanced Coherent Optical Network (BEACON) mission is a search for new physics beyond general relativity by measuring the curvature of relativistic space-time around Earth. This curvature is characterized by the Eddington parameter \\gamma -- the most fundamental relativistic gravity parameter and a direct measure for the presence of new physical interactions. BEACON will achieve an accuracy of 1 x 10^{-9} in measuring the parameter \\gamma, thereby going a factor of 30,000 beyond the present best result involving the Cassini spacecraft. Secondary mission objectives include: (i) a direct measurement of the "frame-dragging" and geodetic precessions in the Earth's rotational gravitomagnetic field, to 0.05% and 0.03% accuracy correspondingly, (ii) first measurement of gravity's non-linear effects on light and corresponding 2nd order spatial metric's effects to 0.01% accuracy. BEACON will lead to robust advances in tests of fundamental physics -- this mission could disco...

  11. Some early results from the ATS-6 radio beacon experiment

    International Nuclear Information System (INIS)

    The multifrequency satellite radio beacon enables the measurement of the columnar electron content of the ionosphere and plasmasphere along the ray path and its spatial and temporal structure. Measurements include modulation phase, Faraday rotation, and amplitude. The characteristics of the beacon transmitter and its design are presented together with the design of the Boulder receiver and antennas and the calibration procedures. A shape factor F is defined which depends on the electron density and geomagnetic field distributions. It is found that F varies by about 30 percent from day to night. It is shown that the ratio of the plasmaspheric content to total content varies from about 0.08 during the day to about 0.35 at night. Other examples which are presented to illustrate the uses of the radio beacon include sunrise effects, solar flare enhancements of total content, and the ionospheric storms of early July 1974

  12. Comparison of BEACON and COMPARE reactor cavity subcompartment analyses

    International Nuclear Information System (INIS)

    In this study, a more advanced best-estimate containment code, BEACON-MOD3A, was ued to calculate force and moment loads resulting from a high-energy blowdown for two reactor cavity geometries previously analyzed with the licensing computer code COMPARE-MOD1A. The BEACON force and moment loads were compared with the COMPARE results to determine the safety margins provided by the COMPARE code. The forces and moments calculated by the codes were found to be different, although not in any consistent manner, for the two reactor cavity geometries studied. Therefore, generic summary statements regarding margins cannot be made because of the effects of the detailed physical configuration. However, differences in the BEACON and COMPARE calculated forces and moments can be attributed to differences in the modeling assumptions used in the codes and the analyses

  13. Detection of thermocouple malfunction in the Beacon system

    International Nuclear Information System (INIS)

    The BEACON system uses Core Exit Thermocouples (T/C) extensively for continuous radial power distribution monitoring. The T/C's are used to adjust the reference power distribution generated by the BEACON system to match the current radial power distribution. T/C reliability, repeatability, and relative accuracy have been very satisfactory. However, it is very important to detect any T/C malfunctions during operation, since a T/C signal change caused by an undetected malfunction can lead to serious errors in the radial power distribution developed by BEACON. A simple procedure has been developed which is capable of discriminating between changes in T/C signals caused by actual changes in reactor conditions and signal changes caused by T/C malfunctions

  14. Evaluation of BEACON-COLSS Core Monitoring System Benefits

    International Nuclear Information System (INIS)

    In Korean Standard Nuclear Power Plant COLSS (Core Operating Limit Supervisory System) is used to monitor the DNBR Power Operating Limit (DNBRPOL) and Linear Heat Rate POL (KWPFPOL). Westinghouse and KNFC have developed an upgraded core monitoring system by combining the BEACONTM core monitoring system1 (Best Estimate Analyzer for Core Operation . Nuclear) and COLSS into an integrated product that is called BEACON-COLSS. BEACON-COLSS generates the 3-D power distribution corrected by the in-core detectors measurements. The 3-D core power distribution methodology in BEACON-COLSS is significantly better than the synthesis methodology in COLSS. BEACONCOLSS uses the CETOP-D2 thermal hydraulic code instead of CETOP-1. CETOP-D is a multi-channel thermal hydraulics code that will provide more accurate DNBR calculations than the DNBR calculators currently used in COLSS

  15. Distributed localization using mobile beacons in wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    KUANG Xing-hong; SHAO Hui-he

    2007-01-01

    A new distributed node localization algorithm named mobile beacons-improved particle filter (MB-IPF) was proposed. In the algorithm, the mobile nodes equipped with globe position system (GPS) move around in the wireless sensor network (WSN) field based on the Gauss-Markov mobility model, and periodically broadcast the beacon messages. Each unknown node estimates its location in a fully distributed mode based on the received mobile beacons. The localization algorithm is based on the IPF and several refinements, including the proposed weighted centroid algorithm, the residual resampling algorithm, and the markov chain monte carlo (MCMC) method etc., which were also introduced for performance improvement. The simulation results show that our proposed algorithm is efficient for most applications.

  16. Omnidirectional beacon-localization using a catadioptric system.

    Science.gov (United States)

    Shen, Thomas C; Drost, Robert J; Sadler, Brian M; Rzasa, John R; Davis, Christopher C

    2016-04-01

    We present a catadioptric beacon localization system that can provide mobile network nodes with omnidirectional situational awareness of neighboring nodes. In this system, a receiver composed of a hyperboloidal mirror and camera is used to estimate the azimuth, elevation, and range of an LED beacon. We provide a general framework for understanding the propagation of error in the angle-of-arrival estimation and then present an experimental realization of such a system. The situational awareness provided by the proposed system can enable the alignment of communication nodes in an optical wireless network, which may be particularly useful in addressing RF-denied environments. PMID:27136988

  17. Experience with the BEACON core monitoring and support system

    International Nuclear Information System (INIS)

    Westinghouse has developed an advanced operational core monitoring and support package called BEACON which uses current instrumentation in conjunction with a fully analytical methodology for on-line generation of 3-D power distributions. The system provides core monitoring, core measurement reduction, core analysis and follow, and core predictions. The heart of the system is a very fast and accurate three dimensional nodal code which is used for core monitoring, simulation, and predictions. The system has been installed at several sites, and extensive feedback has been obtained. A number of tests have been performed for the validation of the BEACON system for core monitoring and core predictions

  18. Privacy Risks from Genomic Data-Sharing Beacons

    OpenAIRE

    Shringarpure, Suyash S.; Bustamante, Carlos D.

    2015-01-01

    The human genetics community needs robust protocols that enable secure sharing of genomic data from participants in genetic research. Beacons are web servers that answer allele-presence queries—such as “Do you have a genome that has a specific nucleotide (e.g., A) at a specific genomic position (e.g., position 11,272 on chromosome 1)?”—with either “yes” or “no.” Here, we show that individuals in a beacon are susceptible to re-identification even if the only data shared include presence or abs...

  19. BEACON SYNCHRONIZATION TECHNOLOGY FOR “BEIDOU” TERRESTRIAL IMPROVEMENT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    WEIJin-chen; TANGJi-qiang; SHENFeng

    2005-01-01

    Synchronization is an essential technology in the radio navigation system. The technique for improving the “Beidou” positioning ability is presented through constituting the terrestrial improvement system, and the beacon synchronization of the improvement system with the “Beidou” one-way time transfer model is realized.The direct digital synthesis (DDS) is adopted to generate the pseudo-random code clock having high precision and stability. Meanwhile, the CPLD device is used to design the synchronization pulse picking-up module, the spread spectrum PN code generator and the spread spectrum modulator. Measurement results indicate that the beacon synchronization has the high precision and the stability.

  20. Frequency Estimator Performance for a Software-Based Beacon Receiver

    Science.gov (United States)

    Zemba, Michael J.; Morse, Jacquelynne Rose; Nessel, James A.; Miranda, Felix

    2014-01-01

    As propagation terminals have evolved, their design has trended more toward a software-based approach that facilitates convenient adjustment and customization of the receiver algorithms. One potential improvement is the implementation of a frequency estimation algorithm, through which the primary frequency component of the received signal can be estimated with a much greater resolution than with a simple peak search of the FFT spectrum. To select an estimator for usage in a QV-band beacon receiver, analysis of six frequency estimators was conducted to characterize their effectiveness as they relate to beacon receiver design.

  1. Omnidirectional beacon-localization using a catadioptric system.

    Science.gov (United States)

    Shen, Thomas C; Drost, Robert J; Sadler, Brian M; Rzasa, John R; Davis, Christopher C

    2016-04-01

    We present a catadioptric beacon localization system that can provide mobile network nodes with omnidirectional situational awareness of neighboring nodes. In this system, a receiver composed of a hyperboloidal mirror and camera is used to estimate the azimuth, elevation, and range of an LED beacon. We provide a general framework for understanding the propagation of error in the angle-of-arrival estimation and then present an experimental realization of such a system. The situational awareness provided by the proposed system can enable the alignment of communication nodes in an optical wireless network, which may be particularly useful in addressing RF-denied environments.

  2. mRNA detection in living cell using phosphorothioate-modified molecular beacon

    Institute of Scientific and Technical Information of China (English)

    TANG HongXing; YANG XiaoHai; WANG KeMin; TAN WeiHong; LI Wei

    2009-01-01

    In this study, GFP mRNA in COS-7 cell and GFP-transfected COS-7 cell was detected in real time using phosphorothioate-modified molecular beacon based on living cell imaging method. Results showed that phosphorothioate-modified molecular beacon still kept the advantages of molecular beacon, such as, excellent selectivity, high sensitivity, and no separation detection. In addition, this modification could significantly increase the nuclease resistance of molecular beacon. Phosphorothioate-modified molecular beacon can efficiently reduce the false positive signal and improve the accuracy of living cell mRNA detection.

  3. Optimalization of Beacon Selection for Localization in Wireless AD-HOC Networks

    Directory of Open Access Journals (Sweden)

    Martin Matula

    2008-01-01

    Full Text Available In this paper we engage in optimalization of convenient beacons for localization position of a node in the ad-hoc network. An algorithm designed by us localizes position of moving or static node by RSS (Received Signal Strength method and trilateration. At first, localization of unknown node runs by combination of all beacons. Than optimalizating algorithmreduces the number of beacons (and repeats localization, while only three left. Its reduction is based on highest levels of received signal strength. It is only when signals are from the nearest beacons. Position localizating exactness is statistically interpreted from all localization by beacons combination and its repeating.

  4. Gold nanoparticle-based beacon to detect STAT5b mRNA expression in living cells: a case optimized by bioinformatics screen

    Directory of Open Access Journals (Sweden)

    Deng D

    2015-04-01

    Full Text Available Dawei Deng,* Yang Li,* Jianpeng Xue, Jie Wang, Guanhua Ai, Xin Li, Yueqing GuDepartment of Biomedical Engineering, China Pharmaceutical University, Nanjing, People’s Republic of China*These authors contributed equally to this workAbstract: Messenger RNA (mRNA, a single-strand ribonucleic acid with functional gene information is usually abnormally expressed in cancer cells and has become a promising biomarker for the study of tumor progress. Hairpin DNA-coated gold nanoparticle (hDAuNP beacon containing a bare gold nanoparticle (AuNP as fluorescence quencher and thiol-terminated fluorescently labeled stem–loop–stem oligonucleotide sequences attached by Au–S bond is currently a new nanoscale biodiagnostic platform capable of mRNA detection, in which the design of the loop region sequence is crucial for hybridizing with the target mRNA. Hence, in this study, to improve the sensitivity and selectivity of hDAuNP beacon simultaneously, the loop region of hairpin DNA was screened by bioinformatics strategy. Here, signal transducer and activator of transcription 5b (STAT5b mRNA was selected and used as a practical example. The results from the combined characterizations using optical techniques, flow cytometry assay, and cell microscopic imaging showed that after optimization, the as-prepared hDAuNP beacon had higher selectivity and sensitivity for the detection of STAT5b mRNA in living cells, as compared with our previous beacon. Thus, the bioinformatics method may be a promising new strategy for assisting in the designing of the hDAuNP beacon, extending its application in the detection of mRNA expression and the resultant mRNA-based biological processes and disease pathogenesis.Keywords: molecular beacon, bioinformatics, gold nanoparticle, STAT5b mRNA, visual detection

  5. The Westinghouse BEACON on-line core monitoring system

    International Nuclear Information System (INIS)

    BEACON (Best Estimate Analysis of Core Operations - Nuclear), a core monitoring and operational support package developed by Westinghouse, has been installed at many operating PWRs worldwide. The BEACON system is a real-time monitoring system which can be used in plants with both fixed and movable incore detector systems and utilizes an on-line nodal model combined with core instrumentation data to provide continuous core power distribution monitoring. In addition, accurate core-predictive capabilities utilizing a full core nodal model updated according to plant operating history can be made to provide operational support. Core history information is kept and displayed to help operators anticipate core behavior and take pro-active control actions. The BEACON system has been licensed by the U.S. Nuclear Regulatory Commission for direct, continuous monitoring of DNBR and peak linear heat rate. This allows BEACON to be integrated into the plant technical specifications to permit significant relaxation of operating limitations defined by conventional technical specifications. (author). 4 refs, 2 figs, 1 tab

  6. DNAzyme catalytic beacon sensors that resist temperature-dependent variations†

    OpenAIRE

    Nagraj, Nandini; Liu, Juewen; Sterling, Stephanie; Wu, Jenny; Lu, Yi

    2009-01-01

    The temperature-dependent variability of a Pb2+-specific 8-17E DNAzyme catalytic beacon sensor has been addressed through the introduction of mismatches in the DNAzyme, and the resulting sensors resist temperature-dependent variations from 4 to 30 °C.

  7. The morpholino molecular beacon for specific RNA visualization in vivo.

    Science.gov (United States)

    Chen, Jianbin; Wu, Jikui; Hong, Yunhan

    2016-02-21

    A non-invasive fluorescent probe, morpholino molecular beacon (MO-MB), was designed for RNA visualization in vivo. Featuring negligible toxicity, stability, and high target specificity in living embryos, MO-MB is superior to conventional probes and has the potential for specific RNA visualization in basic biological and clinical research. PMID:26810703

  8. Exploration of Adaptive Beaconing for Efficient Intervehicle Safety Communication

    NARCIS (Netherlands)

    Schmidt, Robert K.; Leinmüller, Tim; Schoch, Elmar; Kargl, Frank; Schäfer, Günther

    2010-01-01

    In the future intervehicle communication will make driving safer, easier, and more comfortable. As a cornerstone of the system, vehicles need to be aware of other vehicles in the vicinity. This cooperative awareness is achieved by beaconing, the exchange of periodic single-hop broadcast messages tha

  9. Remarks on the observability of single beacon underwater navigation

    DEFF Research Database (Denmark)

    Jouffroy, Jerome; Ross, Andrew

    This paper contributes a simple and intuitive result in the analysis of underwater navigation using a single ranging beacon. This analysis should help with the design of small and lightweight underwater vehicles by reducing the amount of instrumentation required for accurate navigation. The concept...

  10. The morpholino molecular beacon for specific RNA visualization in vivo.

    Science.gov (United States)

    Chen, Jianbin; Wu, Jikui; Hong, Yunhan

    2016-02-21

    A non-invasive fluorescent probe, morpholino molecular beacon (MO-MB), was designed for RNA visualization in vivo. Featuring negligible toxicity, stability, and high target specificity in living embryos, MO-MB is superior to conventional probes and has the potential for specific RNA visualization in basic biological and clinical research.

  11. BEACON: automated tool for Bacterial GEnome Annotation ComparisON

    KAUST Repository

    Kalkatawi, Manal Matoq Saeed

    2015-08-18

    Background Genome annotation is one way of summarizing the existing knowledge about genomic characteristics of an organism. There has been an increased interest during the last several decades in computer-based structural and functional genome annotation. Many methods for this purpose have been developed for eukaryotes and prokaryotes. Our study focuses on comparison of functional annotations of prokaryotic genomes. To the best of our knowledge there is no fully automated system for detailed comparison of functional genome annotations generated by different annotation methods (AMs). Results The presence of many AMs and development of new ones introduce needs to: a/ compare different annotations for a single genome, and b/ generate annotation by combining individual ones. To address these issues we developed an Automated Tool for Bacterial GEnome Annotation ComparisON (BEACON) that benefits both AM developers and annotation analysers. BEACON provides detailed comparison of gene function annotations of prokaryotic genomes obtained by different AMs and generates extended annotations through combination of individual ones. For the illustration of BEACON’s utility, we provide a comparison analysis of multiple different annotations generated for four genomes and show on these examples that the extended annotation can increase the number of genes annotated by putative functions up to 27 %, while the number of genes without any function assignment is reduced. Conclusions We developed BEACON, a fast tool for an automated and a systematic comparison of different annotations of single genomes. The extended annotation assigns putative functions to many genes with unknown functions. BEACON is available under GNU General Public License version 3.0 and is accessible at: http://www.cbrc.kaust.edu.sa/BEACON/

  12. Ultrasonic Localization of Mobile Robot Using Active Beacons and Code Correlation

    Science.gov (United States)

    Peca, Marek

    Ultrasonic localization system for planar mobile robot inside of a restricted field is presented. System is based on stationary active beacons and measurement of distances between beacons and robot, using cross-correlation of pseudorandom binary sequences (PRBSes). Due to high demand of dynamic reserve imposed by range ratio in our specific task, both code- as well as frequency-divided media access has been utilized. For the same reason, 1-bit signal quantization has been abandoned in favor of higher resolution in receiver analog-to-digital conversion. Finally, dynamic estimation of the position is recommended over analytic calculation. The final solution uses the extended Kalman filter (EKF), equipped with erroneous measurement detection, initial state computation, and recovery from being lost. EKF also performs data-fusion with odometry measurement. Unlike the approach in majority of works on mobile robot localization, a model, actuated solely by additive process noise, is presented for the data-fusion. It offers estimation of heading angle, and remains locally observable. Simplistic double integrator model of motion dynamics is described, and the importance of clock dynamics is emphasized.

  13. The BEACON on-line core monitoring system. Functional upgrades and applications

    International Nuclear Information System (INIS)

    The BEACONTM core monitor system has been in commercial operation since 1989 and was licensed by the USNRC for on-line core power distribution and thermal power limit monitoring in 1994. Since that time BEACON has been installed at 17 plants. Each of these customers has a different perspective on the use of data from BEACON and a different approach on the application of BEACON to support their plant operations. To support these varied needs and approaches the BEACON system has been divided into three operational levels to better match the system functions to the customer needs and approaches to system integration. Based on customer feedback, the BEACON system was upgraded in some areas and streamlined in other areas to better support the needs of each customer. The three operational levels of the BEACON system, the major product upgrades and system evolution that has taken place to support the needs and applications of our customers are discussed. (authors)

  14. Reliability analysis of a multiple-laser-diode beacon for intersatellite links

    Science.gov (United States)

    Mauroschat, Andreas

    1991-06-01

    Monte Carlo simulations are used to investigate and evaluate different design options for the SILEX acquisition beacon. A minimum specification for the quality of the optical coupling between the laser diodes and the beacon output for which the beacon meets its power specification with the required reliability is established. An improved reliability is demonstrated for beacon designs with an optimized thermal design including the control of the thermal wall temperature and the conductive coupling between the beacon emission unit and the terminal radiator. Such an optimized thermal design also offers the possibility of mass savings of the optical terminal, since only a very light thermal wall is needed for the beacon. The total power control of the laser diodes is demonstrated to be the best mode of operation.

  15. SU-E-J-257: Image Artifacts Caused by Implanted Calypso Beacons in MRI Studies

    International Nuclear Information System (INIS)

    Purpose: The presence of Calypso Beacon-transponders in patients can cause artifacts during MRI imaging studies. This could be a problem for post-treatment follow up of cancer patients using MRI studies to evaluate metastasis and for functional imaging studies.This work assesses (1) the volume immediately surrounding the transponders that will not be visualized by the MRI due to the beacons, and (2) the dependence of the non-visualized volume on beacon orientation, and scanning techniques. Methods: Two phantoms were used in this study (1) water filled box, (2) and a 2300 cc block of pork meat. Calypso beacons were implanted in the phantoms both in parallel and perpendicular orientations with respect to the MR scanner magnetic field. MR image series of the phantom were obtained with on a 1.0T high field open MR-SIM with multiple pulse sequences, for example, T1-weighted fast field echo and T2-weighted turbo spin echo. Results: On average, a no-signal region with 2 cm radius and 3 cm length was measured. Image artifacts are more significant when beacons are placed parallel to scanner magnetic field; the no-signal area around the beacon was about 0.5 cm larger in orthogonal orientation. The no-signal region surrounding the beacons slightly varies in dimension for the different pulse sequences. Conclusion: The use of Calypso beacons can prohibit the use of MRI studies in post-treatment assessments, especially in the immediate region surrounding the implanted beacon. A characterization of the MR scanner by identifying the no-signal regions due to implanted beacons is essential. This may render the use of Calypso beacons useful for some cases and give the treating physician a chance to identify those patients prior to beacon implantation

  16. Enhanced Beacon Enabled Mode For Improved IEEE 802.15.4 Low Data Rate Performance

    OpenAIRE

    Li, Xiaoyun; Bleakley, Chris J.; Bober, Wojciech

    2012-01-01

    This paper proposes enhancements to IEEE 802.15.4 Beacon-Enabled Mode that provide improved network performance and lower power consumption for low data rate applications. The proposed mode utilizes a Synchronous Low Power Listening technique that allows nodes to sleep for multiple Beacon Intervals and subsequently recover Beacon synchronization in a power efficient manner. The proposed mode also incorporates a Periodic Wakeup scheme that allows nodes to transmit at scheduled times during the...

  17. SU-E-J-257: Image Artifacts Caused by Implanted Calypso Beacons in MRI Studies

    Energy Technology Data Exchange (ETDEWEB)

    Amro, H; Chetty, I; Gordon, J; Wen, N [Henry Ford Health System, Detroit, MI (United States)

    2014-06-01

    Purpose: The presence of Calypso Beacon-transponders in patients can cause artifacts during MRI imaging studies. This could be a problem for post-treatment follow up of cancer patients using MRI studies to evaluate metastasis and for functional imaging studies.This work assesses (1) the volume immediately surrounding the transponders that will not be visualized by the MRI due to the beacons, and (2) the dependence of the non-visualized volume on beacon orientation, and scanning techniques. Methods: Two phantoms were used in this study (1) water filled box, (2) and a 2300 cc block of pork meat. Calypso beacons were implanted in the phantoms both in parallel and perpendicular orientations with respect to the MR scanner magnetic field. MR image series of the phantom were obtained with on a 1.0T high field open MR-SIM with multiple pulse sequences, for example, T1-weighted fast field echo and T2-weighted turbo spin echo. Results: On average, a no-signal region with 2 cm radius and 3 cm length was measured. Image artifacts are more significant when beacons are placed parallel to scanner magnetic field; the no-signal area around the beacon was about 0.5 cm larger in orthogonal orientation. The no-signal region surrounding the beacons slightly varies in dimension for the different pulse sequences. Conclusion: The use of Calypso beacons can prohibit the use of MRI studies in post-treatment assessments, especially in the immediate region surrounding the implanted beacon. A characterization of the MR scanner by identifying the no-signal regions due to implanted beacons is essential. This may render the use of Calypso beacons useful for some cases and give the treating physician a chance to identify those patients prior to beacon implantation.

  18. Q-Band (37 to 41 GHz) Satellite Beacon Architecture for RF Propagation Experiments

    Science.gov (United States)

    Simons, Rainee N.; Wintucky, Edwin G.

    2014-01-01

    In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation experiments at Q-band (37 to 41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed cutparaboloidal reflector.

  19. Q-Band (37-41 GHz) Satellite Beacon Architecture for RF Propagation Experiments

    Science.gov (United States)

    Simmons, Rainee N.; Wintucky, Edwin G.

    2012-01-01

    In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation experiments at Q-band (37-41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed cut-paraboloidal reflector.

  20. Remote sensing of the ionosphere using satellite radio beacons

    International Nuclear Information System (INIS)

    Since the launch of Sputnik I in 1957, satellite radio beacons have been used to measure the total electron content of the ionosphere. A review of the role of satellite beacons in studies of the vertical and spatial structure of the total electron content and on the occurrence of plasma irregularities, both of which affect transionospheric radio signals, is presented. Measurements of Faraday rotation and time of flight give information on the topside of the ionosphere and on the protonosphere. Morphological studies show that the slab thickness of the ionosphere depends on the solar index but is approximately independent of geographical location. Scintillation of amplitude, phase, polarization, and angle provide information on plasma irregularity occurrence in space and time. (author). 23 refs., 16 figs ., 4 tabs

  1. iBeacon-perustaiset maamerkit sisätilapaikannuksessa

    OpenAIRE

    Kotsalo, Mikko

    2015-01-01

    Tämän opinnäytetyön aihe saatiin HAMKin Älykkäät palvelut MATEC-tutkimusryhmästä. MATECssa on käynnissä koko vuoden kestävä projekti, Itsenäistä liikkumista sujuvoittavat iBeacon-tienlöytämisratkaisut (ILSI), minkä osana tämä työ toteutettiin. Projektissa haettiin mahdollisia ratkaisu-ja, käyttäen iBeacon-teknologiaa, jonka avulla voidaan helpottaa sokeiden ihmisten itsenäistä selviytymistä erilaisissa sisätilaympäristöissä. Työn tarkoituksena oli luoda älypuhelinsovellus Applen iOS-alust...

  2. Simulation Analysis of IEEE 802.15.4 Non-beacon Mode at Varying Data Rates

    OpenAIRE

    Z. Abbas; Javaid, N.; Khan, M. A.; S. Ahmed; Qasim, U.; Z. A. Khan

    2012-01-01

    IEEE 802.15.4 standard is designed for low power and low data rate applications with high reliability. It operates in beacon enable and non-beacon enable modes. In this work, we analyze delay, throughput, load, and end-to-end delay of nonbeacon enable mode. Analysis of these parameters are performed at varying data rates. Evaluation of non beacon enabled mode is done in a 10 node network. We limit our analysis to non beacon or unslotted version because, it performs better than other. Protocol...

  3. Improved Bounds for Beacon-Based Coverage and Routing in Simple Rectilinear Polygons

    OpenAIRE

    Bae, Sang Won; Shin, Chan-Su; Vigneron, Antoine

    2015-01-01

    We establish tight bounds for beacon-based coverage problems, and improve the bounds for beacon-based routing problems in simple rectilinear polygons. Specifically, we show that $\\lfloor \\frac{n}{6} \\rfloor$ beacons are always sufficient and sometimes necessary to cover a simple rectilinear polygon $P$ with $n$ vertices. We also prove tight bounds for the case where $P$ is monotone, and we present an optimal linear-time algorithm that computes the beacon-based kernel of $P$. For the routing p...

  4. Rayleigh beacon for measuring the surface profile of a radio telescope

    OpenAIRE

    Padin, S.

    2014-01-01

    Millimeter-wavelength Rayleigh scattering from water droplets in a cloud is proposed as a means of generating a bright beacon for measuring the surface profile of a radio telescope. A λ=3  mm transmitter, with an output power of a few watts, illuminating a stratiform cloud, can generate a beacon with the same flux as Mars in 10 GHz bandwidth, but the beacon has a narrow line width, so it is extremely bright. The key advantage of the beacon is that it can be used at any time, and positioned an...

  5. Rayleigh beacon for measuring the surface profile of a radio telescope.

    Science.gov (United States)

    Padin, S

    2014-12-01

    Millimeter-wavelength Rayleigh scattering from water droplets in a cloud is proposed as a means of generating a bright beacon for measuring the surface profile of a radio telescope. A λ=3  mm transmitter, with an output power of a few watts, illuminating a stratiform cloud, can generate a beacon with the same flux as Mars in 10 GHz bandwidth, but the beacon has a narrow line width, so it is extremely bright. The key advantage of the beacon is that it can be used at any time, and positioned anywhere in the sky, as long as there are clouds.

  6. Beta aerosols beacon, a truly portable continuous air monitor

    International Nuclear Information System (INIS)

    The Beta Aerosols Beacon (BAB) is a portable (57 lbs) continuous air monitor designed to detect airborne radiation. Utilizing solid state detectors has eliminated the use of lead shielding usually necessary for achieving accurate readings in high background areas, making the monitor lightweight as well as portable. The size of a small suitcase, it can be carried into confined work areas, eliminating the requirement for workers to wear respirators for many maintenance tasks. This paper describes the operation and applications of the BAB

  7. Vernetzungspotential durch Nutzung von Normdaten (am Beispiel von GND / BEACON)

    OpenAIRE

    Lordick, Harald

    2015-01-01

    Der Workshop-Beitrag erläutert an praktischen Beispielen, wie Online-Publikationen von ihrer Anreicherung mit IDs der Gemeinsamen Normdatei (GND) profitieren: durch bessere Sichtbarkeit und Recherchierbarkeit, durch Vernetzung mit weiteren Datenangeboten sowie durch Auflösung von Ambiguität. Skizziert wird der Einstieg in das Thema "Linked Data / Semantic Web" als niedrigschwelliger Workflow: Daten mit Ids der GND anreichern, Web-Schnittstelle einrichten, BEACON-D...

  8. Multiplex detection of four pathogenic retroviruses using molecular beacons

    OpenAIRE

    Vet, Jacqueline A. M.; Majithia, Amit R.; Marras, Salvatore A. E.; Tyagi, Sanjay; DUBE, SYAMALIMA; Poiesz, Bernard J; Kramer, Fred Russell

    1999-01-01

    We describe a multiplex nucleic acid assay that identifies and determines the abundance of four different pathogenic retroviruses (HIV-1, HIV-2, and human T-lymphotrophic virus types I and II). Retroviral DNA sequences are amplified in a single, sealed tube by simultaneous PCR assays, and the resulting amplicons are detected in real time by the hybridization of four differently colored, amplicon-specific molecular beacons. The color of the fluorescence generated in the course of amplification...

  9. Adapting Mobile Beacon-Assisted Localization in Wireless Sensor Networks

    OpenAIRE

    Wei Dong; Kougen Zheng; Guodong Teng

    2009-01-01

    The ability to automatically locate sensor nodes is essential in many Wireless Sensor Network (WSN) applications. To reduce the number of beacons, many mobile-assisted approaches have been proposed. Current mobile-assisted approaches for localization require special hardware or belong to centralized localization algorithms involving some deterministic approaches due to the fact that they explicitly consider the impreciseness of location estimates. In this paper, we first propose a range-free,...

  10. Cyclostationary Beacon for Assisting Spectrum Sensing in Opportunistic Spectrum Access

    Directory of Open Access Journals (Sweden)

    Thomas Kaiser

    2011-03-01

    Full Text Available Cognitive radio is a promising solution to the problem of spectrum scarcity by means of allowing secondary radio networks access the spectrum opportunistically. One of the most important issues in cognitive radio is how to detect existing over-the-air signals reliably. Not a few literatures have reported that signals could be detected via their inherent or embedded properties. However, this approach may not be reliable and flexible enough for all kinds of signals with different modulation types. In this paper, we propose a type of multitone beacon signal carrying cyclostationary signatures, which is able to enhance the reliability and efficiency of signal detection at low cost of spectrum overhead. This beacon not only can indicate the presence or absence of user signal but also can reveal some other information helpful to opportunistic spectrum access through the information bits carried on its cyclostationary signatures. It could be applied to device/network identification, indication of spectrum allocation and spectrum rendezvous, both for primary and secondary users. Based on our previous work reported in [1], the generation and detection algorithm of the beacon signal are extended with improved spectral efficiency. Performance is discussed with both computer simulation and testbed validation.

  11. Detection of Toxoplasma gondii with a DNA molecular beacon probe

    Science.gov (United States)

    Zhou, Cun; Xu, Shichao; Yang, Juan; Zhang, Jimei; Dai, Zhao; Zheng, Guo; Sun, Bo; Sun, Shuqing; Feng, Teilin; Zi, Yan; Liang, Chu; Luo, Hao

    2009-07-01

    Toxoplasma gondii is a kind of microscopic parasite that may infect humans, and there are increasing concerns on the early detection of latent Toxoplasma gondii infection in recent years. This research highlights a new type of molecular beacon (MB) fluorescent probe for Toxoplasma DNA testing. We combined high-efficiency fluorescent inorganic core-shell quantum dots-CdTe/ZnS (as fluorescent energy donor) and BHQ-2 (energy acceptor) to the single-strand DNA of Toxoplasma gondii, and a molecular beacon sensing system based on fluorescence resonance energy transfer (FRET) was achieved. Core-shell quantum dots CdTe/ZnS was firstly prepared in aqueous solution, and the influencing factor of its fluorescent properties, including CdTe/Na2S/Zn(CH3COO)2 (v/v), dependence of reaction time, temperature, and pH, is investigated systematically. The synthesized quantum dots and molecular beacon were characterized by transmission electron microscopy (TEM), ultraviolet-visible spectrophotometer (UV-vis), fluorescent spectrophotometer (FS), respectively. The TEM results showed that CdTe/ZnS core-shell quantum dots is ~11nm in size, and the quantum dots is water-soluble well. The sensing ability of target DNA of assembled MB was investigated, and results showed that the target Toxoplasma gonddi DNA can be successfully detected by measuring the change of fluorescence intensity. The results showed that the current sensing probe will be a useful and convenient tool in Toxoplasma gondii early detection.

  12. Performance Analysis of Beacon-Less IEEE 802.15.4 Multi-Hop Networks

    CERN Document Server

    Srivastava, Rachit

    2012-01-01

    We develop an approximate analytical technique for evaluating the performance of multi-hop networks based on beacon-less CSMA/CA as standardised in IEEE 802.15.4, a popular standard for wireless sensor networks. The network comprises sensor nodes, which generate measurement packets, and relay nodes which only forward packets. We consider a detailed stochastic process at each node, and analyse this process taking into account the interaction with neighbouring nodes via certain unknown variables (e.g., channel sensing rates, collision probabilities, etc.). By coupling these analyses of the various nodes, we obtain fixed point equations that can be solved numerically to obtain the unknown variables, thereby yielding approximations of time average performance measures, such as packet discard probabilities and average queueing delays. Different analyses arise for networks with no hidden nodes and networks with hidden nodes. We apply this approach to the performance analysis of tree networks rooted at a data sink. ...

  13. Toxoplasma gondii DNA detection with a magnetic molecular beacon probe

    Science.gov (United States)

    Xu, Shichao; Yao, Cuicui; Wei, Shuoming; Zhang, Jimei; Dai, Zhao; Zheng, Guo; Sun, Bo; Han, Qing; Hu, Fei; Zhou, Hongming

    2008-12-01

    Toxoplasma Gondii infection is widespread in humans worldwide and reported infection rates range from 3%-70%, depending on the populations or geographic areas, and it has been recognized as a potential food safety hazard in our daily life. A magnetic molecular beacon probe (mMBP), based on theory of fluorescence resonance energy transfer (FRET), was currently reported to detect Toxoplasma Gondii DNA. Nano-sized Fe3O4 were primarily prepared by coprecipitation method in aqueous phase with NaOH as precipitator, and was used as magnetic core. The qualified coreshell magnetic quantum dots (mQDs), i.e. CdTe(symbol)Fe3O4, were then achieved by layer-by-layer method when mol ratio of Fe3O4/CdTe is 1/3, pH at 6.0, 30 °C, and reactant solution was refluxed for 30 min, the size of mQDs were determined to be 12-15 nm via transmission electron microscopy (TEM). Over 70% overlap between emission spectrum of mQDs and absorbance spectrum of BHQ-2 was observed, this result suggests the synthesized mQDs and BHQ-2 can be utilized as energy donor and energy acceptor, respectively. The sensing probe was fabricated and a stem-loop Toxoplasma Gondii DNA oligonucleotide was labeled with mQDs at the 5' end and BHQ-2 at 3' end, respectively. Target Toxoplasma gondii DNA was detected under conditions of 37 °C, hybridization for 2h, at pH8.0 in Tris-HCl buffer. About 30% recovery of fluorescence intensity was observed via fluorescence spectrum (FS) after the Toxoplasma gondii DNA was added, which suggested that the Toxoplasma Gondii DNA was successfully detected. Specificity investigation of the mMBP indicated that relative low recovery of fluorescence intensity was obtained when the target DNA with one-base pair mismatch was added, this result indicated the high specificity of the sensing probe. Our research simultaneously indicated that mMBP can be conveniently separated from the unhybridized stem-loop DNA and target DNA, which will be meaningful in DNA sensing and purification process.

  14. TBoPS: a Tree based distributed Beacon only Period Scheduling mechanism for IEEE 802.15.4

    OpenAIRE

    Nefzi, Bilel; Khan, Dawood; Song, Ye-Qiong

    2012-01-01

    International audience IEEE 802.15.4 standard specifies a beacon-enabled mode which provides a synchronization environment using bea- con transmissions. However, this mode is designed for single hop networks and its use in multi-hop networks is not straight- forward. The main challenges of using beacon-enabled mode in multi-hop networks are how to efficiently schedule beacon transmissions to avoid direct and indirect beacon collisions and how to make a schedule tolerant to the clock drifts...

  15. Design of a novel molecular beacon: modification of the stem with artificially genetic alphabet†

    OpenAIRE

    Sheng, Pinpin; Yang, Zunyi; Kim, Youngmi; Wu, Yanrong; Tan, Weihong; Benner, Steven A

    2008-01-01

    A molecular beacon that incorporates components of an artificially expanded genetic information system (Aegis) in its stem is shown not to be opened by unwanted stem invasion by adventitious standard DNA; this should improve the “darkness” of the beacon in real-world applications.

  16. 77 FR 41271 - Safety Zone; Newburgh to Beacon Swim, Newburgh, Hudson River, NY

    Science.gov (United States)

    2012-07-13

    ... Acronyms DHS Department of Homeland Security FR Federal Register CFR Code of Federal Regulations NPRM... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Newburgh to Beacon Swim, Newburgh, Hudson... Newburgh, NY for the annual Newburgh Beacon Swim event. This temporary safety zone is necessary to...

  17. Beacon- and Schema-Based Method for Recognizing Algorithms from Students' Source Code

    Science.gov (United States)

    Taherkhani, Ahmad; Malmi, Lauri

    2013-01-01

    In this paper, we present a method for recognizing algorithms from students programming submissions coded in Java. The method is based on the concept of "programming schemas" and "beacons". Schemas are high-level programming knowledge with detailed knowledge abstracted out, and beacons are statements that imply specific…

  18. 46 CFR 169.744 - Emergency position indicating radio beacon (EPIRB).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Emergency position indicating radio beacon (EPIRB). 169.744 Section 169.744 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS... position indicating radio beacon (EPIRB). Each EPIRB must be marked with the vessel's name....

  19. What Happened to the Beacon Schools? Policy Reform and Educational Equity

    Science.gov (United States)

    Smith, Emma

    2015-01-01

    This paper considers the impact of the Beacon schools initiative on the social and academic characteristics of secondary schools in England. The Beacon schools programme ran from 1998 to 2004 and epitomised the (then) Labour government's focus on school improvement through diversity, collaboration and partnership. This paper looks at variation in…

  20. Crowdsourcing for Context: Regarding Privacy in Beacon Encounters via Contextual Integrity

    Directory of Open Access Journals (Sweden)

    Bello-Ogunu Emmanuel

    2016-07-01

    Full Text Available Research shows that context is important to the privacy perceptions associated with technology. With Bluetooth Low Energy beacons, one of the latest technologies for providing proximity and indoor tracking, the current identifiers that characterize a beacon are not sufficient for ordinary users to make informed privacy decisions about the location information that could be shared. One solution would be to have standardized category and privacy labels, produced by beacon providers or an independent third-party. An alternative solution is to find an approach driven by users, for users. In this paper, we propose a novel crowdsourcing based approach to introduce elements of context in beacon encounters.We demonstrate the effectiveness of this approach through a user study, where participants use a crowd-based mobile app designed to collect beacon category and privacy information as a scavenger hunt game. Results show that our approach was effective in helping users label beacons according to the specific context of a given beacon encounter, as well as the privacy perceptions associated with it. This labeling was done with an accuracy of 92%, and with an acceptance rate of 82% of all recommended crowd labels. Lastly, we conclusively show how crowdsourcing for context can be used towards a user-centric framework for privacy management during beacon encounters.

  1. Molecular beacon probes combined with amplification by NASBA enable homogeneous, real-time detection of RNA

    NARCIS (Netherlands)

    Leone, G.; Schijndel, van H.; Gemen, van B.; Kramer, F.R.; Schoen, C.D.

    1998-01-01

    Molecular beacon probes can be employed in a NASBA amplicon detection system to generate a specific fluorescent signal concomitantly with amplification. A molecular beacon, designed to hybridize within the target sequence, was introduced into NASBA reactions that amplify the genomic RNA of potato le

  2. The Development of Landmark and Beacon Use in Young Children: Evidence from a Touchscreen Search Task

    Science.gov (United States)

    Sutton, Jennifer E.

    2006-01-01

    Children ages 2, 3 and 4 years participated in a novel hide-and-seek search task presented on a touchscreen monitor. On beacon trials, the target hiding place could be located using a beacon cue, but on landmark trials, searching required the use of a nearby landmark cue. In Experiment 1, 2-year-olds performed less accurately than older children…

  3. Molecular beacon – tool for real time studying gene activity in stem cells

    DEFF Research Database (Denmark)

    Ilieva, Mirolyuba; Dufva, Martin

    and cancerogenesis. Molecular beacon technology is based on fluorescence resonance energy transfer (FRET) and the complementary pairing principles. These fluorescent molecular probes are highly specific and sensitive and are one important tool in in vitro diagnostics. Here molecular beacons are used to follow...

  4. 46 CFR 169.555 - Emergency position indicating radio beacon (EPIRB).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Emergency position indicating radio beacon (EPIRB). 169.555 Section 169.555 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS... Emergency position indicating radio beacon (EPIRB). (a) Each vessel certificated for exposed waters...

  5. 46 CFR 169.831 - Emergency position indicating radio beacon (EPIRB).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Emergency position indicating radio beacon (EPIRB). 169.831 Section 169.831 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS... radio beacon (EPIRB). The master shall ensure that— (a) The EPIRB required in § 169.555 of...

  6. Down-regulation of the beacon gene expression in the regenerating rat adrenal cortex.

    Science.gov (United States)

    Ziolkowska, Agnieszka; Rucinski, Marcin; Tyczewska, Marianna; Belloni, Anna Sandra; Nowak, Magdalena; Nussdorfer, Gastone G; Malendowicz, Ludwik K

    2006-12-01

    Beacon, a hypothalamic peptide involved in the regulation of food intake, has been recently shown to be expressed in the adrenal cortex, and to inhibit its secretion and growth. To further characterize the role of beacon in the control of adrenal growth, we investigated the level of beacon gene expression in the regenerating rat adrenal cortex. Conventional reverse transcription-polymerase chain reaction (PCR) and immunocytochemistry demonstrated the expression of beacon mRNA and protein in the adrenals at both days 5 and 8 of regeneration after enucleation and contralateral adrenalectomy. Semiquantitative real time-PCR revealed a net down-regulation of beacon mRNA in the regenerating glands, as compared to the intact adrenal cortex of sham-operated animals. Beacon gene expression was higher at day 8 than at day 5 of regeneration. Mitotic index, as assayed by the stachmokinetic method with vincristin, was negligible in the intact adrenal, but greatly elevated in regenerating gland, with a higher index found at day 5 than at day 8 after surgery. Taken together our findings indicate that the level of beacon gene expression is inversely correlated with the proliferative activity of adrenocortical cells, and suggest that beacon might act as an endogenous inhibitor of adrenocortical growth in the rat.

  7. 46 CFR 28.150 - Emergency Position Indicating Radio Beacons (EPIRBs).

    Science.gov (United States)

    2010-10-01

    ... beacon (EPIRB) as required by 46 CFR part 25, subpart 25.26. Note: Each vessel which uses radio..., as set forth in 47 CFR part 80. ... 46 Shipping 1 2010-10-01 2010-10-01 false Emergency Position Indicating Radio Beacons (EPIRBs)....

  8. PERFORMANCE ANALYSIS OF ANTI-COLLISION ENABLED ROBOT USING HYBRID BEACON SCHEDULING APPROACH

    Directory of Open Access Journals (Sweden)

    P. Prabakaran

    2014-01-01

    Full Text Available In multi-robot environment, when many robots are moving in the same workspace, there is a possibility of their physical collision with themselves as well as with physical objects. In this study, hybrid beacon scheduling protocol is proposed and for avoiding such collisions in robotic mobile environment with low latency and power consumption. The purpose of deploying this protocol is to collect relevant data for processing and reporting. In particular, based on data reporting, the robotic nodes can be classified as time-driven or event-driven. The motivation behind this research is that it dynamically switches between the event-driven data-reporting and time-driven data-reporting schemes. As such, the proposed protocol accurately analyzes the environment being monitored using only moderate resource consumption. We have implemented the proposed protocol on a network simulator and analyzed its behaviors under various conditions.

  9. Uncertainty analysis for the BEACON-COLSS core monitoring system application

    International Nuclear Information System (INIS)

    This paper will cover the measurement uncertainty analysis of BEACON-COLSS core monitoring system. The uncertainty evaluation is made by using a BEACON-COLSS simulation program. By simulating the BEACON on-line operation for analytically generated reactor conditions, accuracy of the 'Measured' results can be evaluated by comparing to analytically generated 'Truth'. The DNB power margin is evaluated based on the Combustion Engineering's Modified Statistical Combination of Uncertainties (MSCU) using the CETOPD code for the DNBR calculation. A BEACON-COLSS simulation program for the uncertainty evaluation function has been established for plant applications. Qualification work has been completed for two Combustion Engineering plants. Results of the BEACON-COLSS measured peaking factors and DNBR power margin are plant type dependent and are applicable to reload cores as long as the core geometry and detector layout are unchanged. (authors)

  10. Directionality based Location Discovery Scheme Using Beacon Nodes with Transmission Capabilities throughout Sensor Network

    Directory of Open Access Journals (Sweden)

    Qinli An

    2013-06-01

    Full Text Available In this paper, we propose a range-free localization scheme for wireless sensor networks (WSNs using four beacon nodes(BNs equipped with a directional antenna with special transmission capabilities for sending wireless beacon signals throughout the sensor network. Each beacon node rotates with a constant angular speed and broadcasts its angular bearings. A sensor node can determine its location by listening to wireless transmissions from the four fixed beacon nodes. The proposed method is based on an angle-of-arrival estimation technique that does not increase the complexity or cost of construction of the sensor nodes. We present error analysis and the best positions of beacon nodes in the proposed method. Numerical results, obtained by simulating several scenarios, show that the algorithm can reach a good level of convergence.

  11. Detection of DNA damage by using hairpin molecular beacon probes and graphene oxide.

    Science.gov (United States)

    Zhou, Jie; Lu, Qian; Tong, Ying; Wei, Wei; Liu, Songqin

    2012-09-15

    A hairpin molecular beacon tagged with carboxyfluorescein in combination with graphene oxide as a quencher reagent was used to detect the DNA damage by chemical reagents. The fluorescence of molecular beacon was quenched sharply by graphene oxide; while in the presence of its complementary DNA the quenching efficiency decreased because their hybridization prevented the strong adsorbability of molecular beacon on graphene oxide. If the complementary DNA was damaged by a chemical reagent and could not form intact duplex structure with molecular beacon, more molecular beacon would adsorb on graphene oxide increasing the quenching efficiency. Thus, damaged DNA could be detected based on different quenching efficiencies afforded by damaged and intact complementary DNA. The damage effects of chlorpyrifos-methyl and three metabolites of styrene such as mandelieaeids, phenylglyoxylieaeids and epoxystyrene on DNA were studied as models. The method for detection of DNA damage was reliable, rapid and simple compared to the biological methods.

  12. Noise correlation-based adaptive polarimetric image representation for contrast enhancement of a polarized beacon in fog

    Science.gov (United States)

    Panigrahi, Swapnesh; Fade, Julien; Alouini, Mehdi

    2015-10-01

    We show the use of a simplified snapshot polarimetric camera along with an adaptive image processing for optimal detection of a polarized light beacon through fog. The adaptive representation is derived using theoretical noise analysis of the data at hand and is shown to be optimal in the Maximum likelihood sense. We report that the contrast enhancing optimal representation that depends on the background noise correlation differs in general from standard representations like polarimetric difference image or polarization filtered image. Lastly, we discuss a detection strategy to reduce the false positive counts.

  13. Complementary terrain/single beacon-based AUV navigation

    Digital Repository Service at National Institute of Oceanography (India)

    Maurya, P.; Curado, T.F.; António, P.

    extracted from the surrounding environment (e.g. terrain information) without incurring in the cost of deploying artificial beacons. Map based navigation, also called Terrain-Aided Navigation (TAN), holds good poten- tial to be used for long range missions...=1 p(xi − Fxi−1 −Guui−1), (14) where ui is the input vector represented in (3) that includes the linear velocity and the heading angle. In view of the main assumptions made before, it is straightforward to compute the likelihood function p(Yk|Xk) = k...

  14. Analysis of measured photon returns from sodium beacons

    International Nuclear Information System (INIS)

    We describe an approach to the computation of photon returns from mesospheric sodium beacons excited by laser pulse trains and discuss as specific examples the required numbers of photons for adaptive-optical compensation of atmospheric turbulence. Computed photon return signals are compared with reported measurements for pulses that are long, short, or comparable to the D2 radiative lifetime (16 ns). Analytical approximations in good agreement with the numerical computations are derived. The results are consistent with experimental data for the different pulse durations. copyright 1998 Optical Society of America

  15. Deep Sea AUV Navigation Using Multiple Acoustic Beacons

    Institute of Scientific and Technical Information of China (English)

    冀大雄; 宋伟; 赵宏宇; 刘健

    2016-01-01

    Navigation is a critical requirement for the operation of Autonomous Underwater Vehicles (AUVs). To estimate the vehicle position, we present an algorithm using an extended Kalman filter (EKF) to integrate dead-reckoning position with acoustic ranges from multiple beacons pre-deployed in the operating environment. Owing to high latency, variable sound speed multipath transmissions and unreliability in acoustic measurements, outlier recognition techniques are proposed as well. The navigation algorithm has been tested by the recorded data of deep sea AUV during field operations in a variety of environments. Our results show the improved performance over prior techniques based on position computation.

  16. Deep sea AUV navigation using multiple acoustic beacons

    Science.gov (United States)

    Ji, Da-xiong; Song, Wei; Zhao, Hong-yu; Liu, Jian

    2016-04-01

    Navigation is a critical requirement for the operation of Autonomous Underwater Vehicles (AUVs). To estimate the vehicle position, we present an algorithm using an extended Kalman filter (EKF) to integrate dead-reckoning position with acoustic ranges from multiple beacons pre-deployed in the operating environment. Owing to high latency, variable sound speed multipath transmissions and unreliability in acoustic measurements, outlier recognition techniques are proposed as well. The navigation algorithm has been tested by the recorded data of deep sea AUV during field operations in a variety of environments. Our results show the improved performance over prior techniques based on position computation.

  17. Beacon Hill公司的水彩系列

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Beacon Hill's公司最新的水彩系列有多种不同的颜色变化,跨度从微妙的柔和的中性色彩一直到充满异国情调的色彩。为了让客户更好地体验到这种水彩的感觉,他们采用了半透明色调的颜料绘制图案。

  18. Molecular Beacon CNT-based Detection of SNPs

    Science.gov (United States)

    Egorova, V. P.; Krylova, H. V.; Lipnevich, I. V.; Veligura, A. A.; Shulitsky, B. G.; Y Fedotenkova, L.

    2015-11-01

    An fluorescence quenching effect due to few-walled carbon nanotubes chemically modified by carboxyl groups has been utilized to discriminate Single Nucleotide Polymorphism (SNP). It was shown that the complex obtained from these nanotube and singlestranded primer DNA is formed due to stacking interactions between the hexagons of the nanotubes and aromatic rings of nucleotide bases as well as due to establishing of hydrogen bonds between acceptor amine groups of nucleotide bases and donor carboxyl groups of the nanotubes. It has been demonstrated that these complexes may be used to make highly effective DNA biosensors detecting SNPs which operate as molecular beacons.

  19. The CERTO Beacon on CASSIOPE/e-POP and Experiments Using High-Power HF Ionospheric Heaters

    Science.gov (United States)

    Siefring, Carl L.; Bernhardt, Paul A.; James, H. Gordon; Parris, Richard Todd

    2015-06-01

    A new Coherent Electromagnetic Radio Tomography (CERTO) beacon is on the CASSIOPE satellite and part of the enhanced-Polar Outflow Probe (e-POP) suite of scientific instruments. CERTO signals can be used to measure ionospheric Total Electron Content (TEC) and radio scintillations along propagation paths between CERTO and receivers. The combination of CERTO and the array of e-POP in-situ diagnostics form a powerful tool for studying ionospheric plasma processes that have not been previously possible. Of note, the combination CERTO and the Radio Receiver Instrument (RRI), a modern digital receiver, which measures between 10 Hz to 18 MHz in selectable bands allows for innovative High Frequency (HF) radio propagation experiments. The use of high-power HF ionospheric heating facilities for such experiments further allows for repeatable studies of a number of important plasma processes. The new CERTO beacon transmits un-modulated, phase-coherent waves at 150, 400, and 1067 MHz with either right-hand-circular or linear polarization and TEC is measured using either differential phase and/or Faraday rotation. With a linear array of CERTO receivers, TEC data can be used for tomographic imaging of the ionosphere yielding two-dimensional maps of the plasma below the satellite orbit. In addition, the three CERTO frequencies cover a wide range for determination of radio scintillation effects caused by diffraction from propagation through ionospheric irregularities. We will describe the CERTO beacon and several potential innovative experiments using HF heating facilities in conjunction with CERTO, the RRI and other e-POP instruments.

  20. Water absorption length measurement with the ANTARES optical beacon system

    International Nuclear Information System (INIS)

    ANTARES is a neutrino telescope located in the Mediterranean Sea with the aim of detecting high energy neutrinos of extra-terrestrial origin. It consists of a three dimensional array on 12 detection lines of photomultiplier tubes (PMTs) able to detect the Cherenkov light induced by muons produced in the interaction of neutrinos with the surrounding water and seabed. To reach the best angular resolution, good time and positioning calibrations are required. The propagation of Cherenkov photons strongly depends on the optical properties of the sea water, which has an impact on the reconstruction efficiency. The determination of the optical parameters, as the absorption and scattering lengths, is crucial to calculate properly the effective area and the angular resolution of the detector. The ANTARES optical beacon system consists of pulsed and fast, well controlled light sources distributed throughout the detector to carry out in situ the relative time calibration of the detector components. In this contribution we show some results on the sea water optical properties and their stability measured with the optical beacon system.

  1. Inversion of Ionospheric Electron Density from GPS Beacon Observations

    Institute of Scientific and Technical Information of China (English)

    ZouYu-hua; XuJi-sheng

    2003-01-01

    This paper studies the mathematical foundation of time-dependent three-dimensional (3-D) computerized ionospheric tomography (CIT) for reconstructing ionospheric electron density, N~, from ground-based GPS beacon observations. After simplifying the relation between N. and time,the time-dependent 3-D inversion in consideration is reduced to a 3-D tomography with incomplete projections. To see clearly the effects of the incompleteness on the quality of reconstruction under 3-D condition, the formula of 3-D parallelbeam tomogtTaphy is deduced theoretically. After establishing the mathematical foundation, simulations based on actual GPS ray paths with the help of the IRI-90 model are performed,and reasonable time-dependent 3-D distribution images of Ne are obtained when taking proper layout of the network and allowing variable resolutions. The quality of the reconstruction is rather good when compared with the images from the IRI-90 model directly. Therefore, results in this paper demonstrate that imaging of the ionospheric electron density distribution from GPS beacon observations is reasonable in theor yand feasible in practice.

  2. Inversion of Ionospheric Electron Density from GPS Beacon Observations

    Institute of Scientific and Technical Information of China (English)

    Zou Yu-hua; Xu Ji-sheng

    2003-01-01

    This paper studies the mathematical foundation of time-dependent three-dimensional (3-D) computerized ionospheric tomography (CIT) for reconstructing ionospheric electron density, Ne, from ground-based GPS beacon observations. After simplifying the relation between Ne and time,the time-dependent 3-D inversion in consideration is reduced to a 3-D tomography with incomplete projections.To see clearly the effects of the incompleteness on the quality of reconstruction under 3-D condition, the formula of 3-D parallel-beam tomography is deduced theoretically. After establishing the mathematical foundation, simulations based on actual GPS ray paths with the help of the IRI-90 model are performed,and reasonable time-dependent 3-D distribution images of Neare obtained when taking proper layout of the network and allowing variable resolutions. The quality of the reconstruction is rather good when compared with the images from the IRI-90 model directly. Therefore, results in this paper demon-strate that imaging of the ionospheric electron density distri-bution from GPS beacon observations is reasonable in theory and feasible in practice.

  3. Gold nanoparticle fluorescent molecular beacon for low-resolution DQ2 gene HLA typing.

    Science.gov (United States)

    Beni, Valerio; Zewdu, Taye; Joda, Hamdi; Katakis, Ioanis; O'Sullivan, Ciara K

    2012-01-01

    Coeliac disease is an inflammation of the small intestine triggered by gluten ingestion. We present a fluorescent genosensor, exploiting molecular-beacon-functionalized gold nanoparticles, for the identification of human leukocyte antigen (HLA) DQ2 gene, a key genetic factor in coeliac disease. Optimization of sensor performance was achieved by tuning the composition of the oligonucleotide monolayer immobilized on the gold nanoparticle and the molecular beacon design. Co-immobilization of the molecular beacon with a spacing oligonucleotide (thiolated ten-thymine oligonucleotide) in the presence of ten-adenine oligonucleotides resulted in a significant increase of the sensor response owing to improved spacing of the molecular beacons and extension of the distance from the nanoparticle surface, which renders them more available for recognition. Further increase in the response (approximately 40%) was shown to be achievable when the recognition sequence of the molecular beacon was incorporated in the stem. Improvement of the specificity of the molecular beacons was also achieved by the incorporation within their recognition sequence of a one-base mismatch. Finally, gold nanoparticles functionalized with two molecular beacons targeting the DQA1*05* and DQB1*02* alleles allowed the low-resolution typing of the DQ2 gene at the nanomolar level.

  4. Operation flexibility and availability improvements using BEACON, an advanced core monitoring system

    International Nuclear Information System (INIS)

    In response to utilities needs in improving plant operation flexibility and plant availability, Westinghouse introduced the advanced core monitoring and operational support system, BEACON, two years ago. Since then, the continuous development of the BEACON system has led to significant advances in further reducing utilities Operation and Maintenance (O and M) costs. The development of the BEACON system is made possible by two breakthroughs: 1) advanced numerical method to solve the diffusion equations extremely fast and 2) development of cost effective, state-of-the-art computing system, workstation. This paper presents the numerical scheme used in the neutronic solution and how BEACON uses the core instrumentations to provide the continuous three-dimensional (3D) core power distribution. Once the state of the core is known on a continuous basis, several indirect surveillance and/or Technical Specifications on core power distribution can be relaxed or totally eliminated. Section 1 outlines the numerical scheme used in BEACON for solving the diffusion equations and to provide the 3D continuous power distribution. Section 2 describes the hardware requirements. Section 3 discusses applications of BEACON to improve plant operation flexibility and plant availability. Examples of actual BEACON usage to demonstrate its effectiveness are presented in Section 4 and the paper is closed with a summary of future directions. (author). 4 refs, 6 figs

  5. DNA aptamer beacon assay for C-telopeptide and handheld fluorometer to monitor bone resorption.

    Science.gov (United States)

    Bruno, John Gordon; Carrillo, Maria P; Phillips, Taylor; Hanson, Douglas; Bohmann, Jonathan A

    2011-09-01

    A novel DNA aptamer beacon is described for quantification of a 26-amino acid C-telopeptide (CTx) of human type I bone collagen. One aptamer sequence and its reverse complement dominated the aptamer pool (31.6% of sequenced clones). Secondary structures of these aptamers were examined for potential binding pockets. Three-dimensional computer models which analyzed docking topologies and binding energies were in agreement with empirical fluorescence experiments used to select one candidate loop for beacon assay development. All loop structures from the aptamer finalists were end-labeled with TYE 665 and Iowa Black quencher for comparison of beacon fluorescence levels as a function of CTx concentration. The optimal beacon, designated CTx 2R-2h yielded a low ng/ml limit of detection using a commercially available handheld fluorometer. The CTx aptamer beacon bound full-length 26-amino acid CTx peptide, but not a shorter 8-amino acid segment of CTx peptide which is a common target for commercial CTx ELISA kits. The prototype assay was shown to detect CTx peptide from human urine after creatinine and urea were removed by size-exclusion chromatography to prevent nonspecific denaturing of the aptamer beacon. This work demonstrates the potential of aptamer beacons to be utilized for rapid and sensitive bone health monitoring in a handheld or point-of-care format.

  6. Pedestrian and motorists' actions at pedestrian hybrid beacon sites: findings from a pilot study.

    Science.gov (United States)

    Pulugurtha, Srinivas S; Self, Debbie R

    2015-01-01

    This paper focuses on an analysis of pedestrian and motorists' actions at sites with pedestrian hybrid beacons and assesses their effectiveness in improving the safety of pedestrians. Descriptive and statistical analyses (one-tail two-sample T-test and two-proportion Z-test) were conducted using field data collected during morning and evening peak hours at three study sites in the city of Charlotte, NC, before and after the installation of pedestrian hybrid beacons. Further, an analysis was conducted to assess the change in pedestrian and motorists' actions over time (before the installation; 1 month, 3 months, 6 months, and 12 months after the installation). Results showed an increase in average traffic speed at one of the pedestrian hybrid beacon sites while no specific trends were observed at the other two pedestrian hybrid beacon sites. A decrease in the number of motorists not yielding to pedestrians, pedestrians trapped in the middle of the street, and pedestrian-vehicle conflicts were observed at all the three pedestrian hybrid beacon sites. The installation of pedestrian hybrid beacons did not have a negative effect on pedestrian actions at two out of the three sites. Improvements seem to be relatively more consistent 3 months after the installation of the pedestrian hybrid beacon.

  7. Fast molecular beacon hybridization in organic solvents with improved target specificity.

    Science.gov (United States)

    Dave, Neeshma; Liu, Juewen

    2010-12-01

    DNA hybridization is of tremendous importance in biology, bionanotechnology, and biophysics. Molecular beacons are engineered DNA hairpins with a fluorophore and a quencher labeled on each of the two ends. A target DNA can open the hairpin to give an increased fluorescence signal. To date, the majority of molecular beacon detections have been performed only in aqueous buffers. We describe herein DNA detection in nine different organic solvents, methanol, ethanol, isopropanol, acetonitrile, formamide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethylene glycol, and glycerol, varying each up to 75% (v/v). In comparison with detection in water, the detection in organic solvents showed several important features. First, the molecular beacon hybridizes to its target DNA in the presence of all nine solvents up to a certain percentage. Second, the rate of this hybridization was significantly faster in most organic solvents compared with water. For example, in 56% ethanol, the beacon showed a 70-fold rate enhancement. Third, the ability of the molecular beacon to discriminate single-base mismatch is still maintained. Lastly, the DNA melting temperature in the organic solvents showed a solvent concentration-dependent decrease. This study suggests that molecular beacons can be used for applications where organic solvents must be involved or organic solvents can be intentionally added to improve the molecular beacon performance.

  8. Highly selective single nucleotide polymorphism recognition by a chiral (5S) PNA beacon.

    Science.gov (United States)

    Totsingan, Filbert; Tedeschi, Tullia; Sforza, Stefano; Corradini, Roberto; Marchelli, Rosangela

    2009-01-01

    A chiral peptide nucleic acid (PNA) beacon containing a C-5 modified monomer based on L-lysine was synthesized. The terminal amino group of the lysine side chain was linked to a spacer for future applications on surfaces. The PNA beacon bears a carboxyfluorescein fluorophore and a dabcyl quencher at opposite ends. The DNA binding properties were compared with those of a homologous PNA beacon containing only achiral monomers. Both beacons underwent a fluorescence increase in the presence of complementary DNA, with higher efficiency and higher selectivity (evaluated using single mismatched DNA sequences) observed for the chiral monomer containing PNA. Ion exchange (IE) HPLC with fluorimetric detection was used in combination with the beacon for the selective detection of complementary DNA. A fluorescent peak corresponding to the PNA beacon:DNA duplex was observed at a very low detection limit (1 nM). The discriminating capacity of the chiral PNA beacon for a single mismatch was found to be superior to those observed with the unmodified one, thus confirming the potency of chirality for increasing the affinity and specificity of DNA recognition.

  9. Functional upgrades and applications of the BEACON on-line core monitoring system

    International Nuclear Information System (INIS)

    Best Estimate Analysis of Core Operations - Nuclear (BEACON) is a real-time core monitoring and operational support package developed by Westinghouse for use at PWR plants. It uses existing core instrumentation data and an on-line neutronics model to provide continuous core power distribution monitoring. The monitoring system will survey core power thermal limits and show core anomalies graphically thus providing operational guidance. BEACON also has predictive capabilities and maintains a core operating history database. The operational levels and recent major functional updates of BEACON are discussed. Recent and planned applications of the system are described which highlight the benefits of the system updates. (UK)

  10. An analysis of iBeacons and critical minimum distances in device placement

    OpenAIRE

    Malmberg, Ivan

    2014-01-01

    This project has been carried out in, and under the supervision of the Mobile Services Laboratory at the department of Communication Systems, KTH. The task was to explore the technical specifics of the iBeacon technology and its practical limitations in terms of reliability and device placement. In plain text; how close the beacons can be placed to allow for reliable isolation of the pertinent beacon. The main method of reaching the set goal was data capture at certain key positions around th...

  11. Coordinator Discovery and Association in Beacon-Enabled IEEE 802.15.4 Network

    OpenAIRE

    Jae-Young Pyun; Faisal Bashir Hussain

    2013-01-01

    End devices in beacon-enabled IEEE 802.15.4 network rely on passive scan to find the coordinator for association. The latency of coordinator discovery depends on coordinator’s beacon interval length. If beacon interval is long then more time is required for successful discovery and vice versa. The latency of association message exchange in IEEE 802.15.4 is considerably high due to response wait time. It is the time during which the coordinator registers the device and assigns a network addres...

  12. Detecting and Preventing Beacon Replay Attacks in Receiver-Initiated MAC Protocols for Energy Efficient WSNs

    DEFF Research Database (Denmark)

    Di Mauro, Alessio; Fafoutis, Xenofon; Mödersheim, Sebastian Alexander;

    2013-01-01

    In receiver-initiated MAC protocols for Wireless Sensor Networks (WSNs), communication is initiated by the receiver of the data through beacons containing the receiver's identity. In this paper, we consider the case of a network intruder that captures and replays such beacons towards legitimate...... nodes, pretending to have a fake identity within the network. To prevent this attack we propose RAP, a challenge-response authentication protocol that is able to detect and prevent the beacon replay attack. The effectiveness of the protocol is formally verified using OFMC and ProVerif. Furthermore, we...

  13. Easy-to-Build Satellite Beacon Receiver for Propagation Experimentation at Millimeter Bands

    Directory of Open Access Journals (Sweden)

    F. Machado

    2014-04-01

    Full Text Available This paper describes the design and development of a digital satellite beacon receiver for propagation experimentation. Satellite beacons are frequently available for pointing large antennas, but such signals can be used for measuring rain attenuation and other phenomena as, for example, tropospheric scintillation. A fairly inexpensive beacon receiver has been built using off-the-shelf parts. This instrument is not at all bulky making it suitable for easy transportation. This article analyzes the receiver specifications, describes in detail its structure and presents some operational test results.

  14. Experimental study on return signals detection of pulsed sodium laser beacon

    Science.gov (United States)

    Zhou, Wenchao; Chen, Tianjiang; Lu, Yanhua; Yun, Yu; Tian, Xiaoqiang; Huang, Dequan

    2015-02-01

    Using pulsed Sodium laser beacon,the exploration experiment of the return light measurement is carried out. The wavefront of Sodium laser beacon of one pulse and the wavefront of natural star of the same direction are measured using two Shack-Hartmann wavefront sensors simultaneously. The results of experimental data analysis show that the return photons numbers received of Shack-Hartmann wavefront sensor's one subaperture are more than 200, and the intensity of Sodium laser beacon's return light is even and steady. The signal-to-noise ratio of light spot distribution is about 3~5. The statistical variance of each order Zernike coefficient of Sodium laser beacon's wavefront and natural star's wavefront is consistent in the gross, and the pertinency of each order Zernike coefficient is well.

  15. Multi-kW Uplink Fiber-Laser Beacon with Agile Signal Format Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Uplink Laser Beacons for deep-space communication, can benefit greatly from migration to the 1010-1030nm wavelengths, via use of Silicon-APDs on the spacecraft...

  16. Multi-kW Uplink Fiber-Laser Beacon with Agile Signal Format Project

    Data.gov (United States)

    National Aeronautics and Space Administration —  Laser beacons with scalable powers are needed for ground to deep-space optical communication uplinks. They serve as absolute reference for tracking of...

  17. Highly sensitive and rapid bacteria detection using molecular beacon-Au nanoparticles hybrid nanoprobes.

    Science.gov (United States)

    Cao, Jing; Feng, Chao; Liu, Yan; Wang, Shouyu; Liu, Fei

    2014-07-15

    Since many diseases are caused by pathogenic bacterial infections, accurate and rapid detection of pathogenic bacteria is in urgent need to timely apply appropriate treatments and to reduce economic costs. To end this, we designed molecular beacon-Au nanoparticle hybrid nanoprobes to improve the bacterial detection efficiency and sensitivity. Here, we show that the designed molecular beacon modified Au nanoparticles could specifically recognize synthetic DNAs targets and can readily detect targets in clinical samples. Moreover, the hybrid nanoprobes can recognize Escherichia coli within an hour at a concentration of 10(2) cfu/ml, which is 1000-folds sensitive than using molecular beacon directly. Our results show that the molecular beacon-Au nanoparticle hybrid nanoprobes have great potential in medical and biological applications.

  18. LDB: Localization with Directional Beacons for Sparse 3D Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Hanjiang Luo

    2010-01-01

    Full Text Available In this paper, we propose a novel distributed localization scheme LDB, a 3D localization scheme with directional beacons for Underwater Acoustic Sensor Networks (UWA-SNs. LDB localizes sensor nodes using an Autonomous Underwater Vehicle (AUV as a mobile beacon sender. Mounted with a directional transceiver which creates conical shaped directional acoustic beam, the AUV patrols over the 3D deployment volume with predefined trajectory sending beacons with constant interval towards the sensor nodes. By listening two or more beacons sent from the AUV, the nodes can localize themselves silently. Through theoretical analysis, we provide the upper bound of the estimation error of the scheme. We also evaluate the scheme by simulations and the results show that our scheme can achieve a high localization accuracy, even in sparse networks.

  19. Tracking neuronal marker expression inside living differentiating cells using molecular beacons

    DEFF Research Database (Denmark)

    Ilieva, Mirolyuba; Della Vedova, Paolo; Hansen, Ole;

    2013-01-01

    Monitoring gene expression is an important tool for elucidating mechanisms of cellular function. In order to monitor gene expression during nerve cell development, molecular beacon (MB) probes targeting markers representing different stages of neuronal differentiation were designed and synthesized...

  20. Theory of continuous-wave excitation of the sodium beacon

    International Nuclear Information System (INIS)

    We extend our previous analysis of the sodium beacon [J. Opt. Soc. Am. A 15, 217 (1998)] to the case of continuous-wave excitation. Various effects that could be ignored in the case of pulsed excitation, such as the geomagnetic field, the recoil of the sodium atoms upon absorption and emission, and collisions of the sodium atoms with other mesospheric species, are included. Spin-relaxation collisions are among the most important of these effects for the cases considered. Analytical approximations to numerical results are presented, and using a semi-empirical estimate for Na-O2 spin relaxation, we compute photon returns in good agreement with recently reported measurements at the Steward Observatory. copyright 1999 Optical Society of America

  1. BEACON: An application of nodal methods for operational support

    International Nuclear Information System (INIS)

    A practical application of nodal methods is on-line plant operational support. However, to enable plant personnel to take full advantage of a nodal model to support plant operations, (a) a core nodal model must always be up to date with the current core history and conditions, (b) the nodal methods must be fast enough to allow numerous core calculations to be performed in minutes to support engineering decisions, and (c) the system must be easily accessible to engineering personnel at the reactor, their offices, or any other location considered appropriate. A core operational support package developed by Westinghouse called BEACON (best estimate analysis of core operations - nuclear) has been installed at several plants. Results from these plants and numerous in-core flux maps analyzed have demonstrated the accuracy of the model and the effectiveness of the methodology

  2. Beacons of discovery the worldwide science of particle physics

    CERN Document Server

    International Committee for Future Accelerators (ICFA)

    2011-01-01

    To discover what our world is made of and how it works at the most fundamental level is the challenge of particle physics. The tools of particle physics—experiments at particle accelerators and underground laboratories, together with observations of space—bring opportunities for discovery never before within reach. Thousands of scientists from universities and laboratories around the world collaborate to design, build and use unique detectors and accelerators to explore the fundamental physics of matter, energy, space and time. Together, in a common world-wide program of discovery, they provide a deep understanding of the world around us and countless benefits to society. Beacons of Discovery presents a vision of the global science of particle physics at the dawn of a new light on the mystery and beauty of the universe.

  3. Seamless Guidance System Combining GPS, BLE Beacon, and NFC Technologies

    Directory of Open Access Journals (Sweden)

    Rung-Shiang Cheng

    2016-01-01

    Full Text Available Users rely increasingly on Location-Based Services (LBS and automated navigation/guidance systems nowadays. However, while such services are easily implemented in outdoor environments using Global Positioning System (GPS technology, a requirement still exists for accurate localization and guidance schemes in indoor settings. Accordingly, the present study proposes a system based on GPS, Bluetooth Low Energy (BLE beacons, and Near Field Communication (NFC technology. Through establishing graphic information and the design of algorithm, this study develops a guidance system for indoors and outdoors on smart phones, wishing to give user perfect smart life through this system. The proposed system is implemented on a smart phone and evaluated on a student campus environment. The experimental results confirm the ability of the proposed app to switch automatically from an outdoor mode to an indoor mode and to guide the user to requested target destination via the shortest possible route.

  4. Creation of a Library Tour Application for Mobile Equipment using iBeacon Technology

    OpenAIRE

    Jonathan Bradley; Neal Henshaw; Liz McVoy; Amanda French; Keith Gilbertson; Lisa Becksford; Elisabeth Givens

    2016-01-01

    We describe the design, development, and deployment of a library tour application utilizing Bluetooth Low Energy devices know as iBeacons. The tour application will serve as library orientation for incoming students. The students visit stations in the library with mobile equipment running a special tour app. When the app detects a beacon nearby, it automatically plays a video that describes the current location. After the tour, students are assessed according to the defined learning objective...

  5. Localization with a Mobile Beacon Based on Compressive Sensing in Wireless Sensor Networks

    OpenAIRE

    Bing Cui; Hui Huang; Yunlong Xu; Chunhui Zhao

    2013-01-01

    Node localization technology is especially important to most applications of wireless sensor network. However, each mobile beacon needs to broadcast its current position many times, and locating all the nodes must take a long time in most of the localization algorithms. In order to solve these problems, we propose a novel range-free localization algorithm—localization with a mobile beacon based on compressive sensing (LMCS). LMCS makes use of compressive sensing (CS) to get the related degree...

  6. A Beacon Interval Shifting Scheme for Interference Mitigation in Body Area Networks

    OpenAIRE

    Seungku Kim; Seokhwan Kim; Jin-Woo Kim; Doo-Seop Eom

    2012-01-01

    This paper investigates the issue of interference avoidance in body area networks (BANs). IEEE 802.15 Task Group 6 presented several schemes to reduce such interference, but these schemes are still not proper solutions for BANs. We present a novel distributed TDMA-based beacon interval shifting scheme that reduces interference in the BANs. A design goal of the scheme is to avoid the wakeup period of each BAN coinciding with other networks by employing carrier sensing before a beacon transmiss...

  7. Static beacons based indoor positioning method for improving room-level accuracy

    OpenAIRE

    Miekk-oja, Ville

    2015-01-01

    Demand for indoor positioning applications has been growing lately. Indoor positioning is used for example in hospitals for patient tracking, and in airports for finding correct gates. Requirements in indoor positioning have become more strict with demands for a higher accuracy. This thesis presents a method for improving the room-level accuracy of a positioning system by using static beacons. As a static beacon, Bluetooth low energy modules will be used to test how much they can improve...

  8. Remote tracking of a magnetic receiver using low frequency beacons

    International Nuclear Information System (INIS)

    Low frequency magnetic fields feature high penetration ability, which allows communication, localization, and tracking in environments where radio or acoustic waves are blocked or distorted by multipath interferences. In the present work, we propose a method for tracking a magnetic receiver using beacons of low frequency magnetic field, where the receiver includes a tri-axial search-coil magnetometer. Measuring the beacons’ magnetic fields and calculating the total-field signals enables localization without restrictions on magnetometer orientation, allowing on-the-move tracking. The total-field signals are used by a global search method, e.g., simulated annealing (SA) algorithm, to localize the receiver. The magnetic field produced by each beacon has a dipole structure and is governed by the beacon’s position and magnetic moment. We have investigated two different methods for estimating beacons’ magnetic moments prior to localization. The first method requires directional measurements, whereas for the second method the total-field signal is used. Effectiveness of these methods has been proved in numerous field tests. In the present work, we introduce a method for tracking a moving receiver by successive localizations. Using previous localization as a starting point of the search method for the next localization can reduce execution time and chances for divergence. The proposed method has been tested using numerous computer simulations. Successful system operation has been verified in field conditions. The good tracking capability together with simple implementation makes the proposed method attractive for real-time, low power field applications, such as mobile robots navigation. (paper)

  9. Remote tracking of a magnetic receiver using low frequency beacons

    Science.gov (United States)

    Sheinker, Arie; Ginzburg, Boris; Salomonski, Nizan; Frumkis, Lev; Kaplan, Ben-Zion

    2014-10-01

    Low frequency magnetic fields feature high penetration ability, which allows communication, localization, and tracking in environments where radio or acoustic waves are blocked or distorted by multipath interferences. In the present work, we propose a method for tracking a magnetic receiver using beacons of low frequency magnetic field, where the receiver includes a tri-axial search-coil magnetometer. Measuring the beacons’ magnetic fields and calculating the total-field signals enables localization without restrictions on magnetometer orientation, allowing on-the-move tracking. The total-field signals are used by a global search method, e.g., simulated annealing (SA) algorithm, to localize the receiver. The magnetic field produced by each beacon has a dipole structure and is governed by the beacon’s position and magnetic moment. We have investigated two different methods for estimating beacons’ magnetic moments prior to localization. The first method requires directional measurements, whereas for the second method the total-field signal is used. Effectiveness of these methods has been proved in numerous field tests. In the present work, we introduce a method for tracking a moving receiver by successive localizations. Using previous localization as a starting point of the search method for the next localization can reduce execution time and chances for divergence. The proposed method has been tested using numerous computer simulations. Successful system operation has been verified in field conditions. The good tracking capability together with simple implementation makes the proposed method attractive for real-time, low power field applications, such as mobile robots navigation.

  10. VANETs 中 beacon 的传输攻击实时检测算法%Detection of jamming transmission of beacon in vehicular networks

    Institute of Scientific and Technical Information of China (English)

    陈丹; 彭利民

    2015-01-01

    车载自组织网(vehicular Ad hoc networks,VANETs)中的车辆通过周期交互 beacon 实现信息共享,从而提高交通安全,然而 VANETs 无线网络特性系统易遭受多类攻击,特别是对 beacon 的传输攻击,即干扰 beacon的传输,其严重影响 VANETs 的安全性能。为此,建立车队 platooning 模型,提出实时检测干扰 beacon 传输的攻击方案。该方案首先将节点 beacon 传输时间分为相互独立的时隙,并依据此时隙将车辆分为不同的群,使得群间的 beacon 彼此不碰撞,从而降低 beacon 被干扰的概率。最后,针对两类攻击类型进行仿真。仿真结果表明,提出的检测攻击方案具有良好的性能,初始检测时间小于150 ms,平均检测率不低于0.9。在两个干扰者的情况下,漏警率小于0.15,平均的虚警率小于0.2。%The cooperation between the vehicles in the VANET is achieved by the frequent exchange of periodic broadcast messages carrying information on vehicle position and velocity,which is referred to as beacons,which is in favor of improving the security of VANET.However,the nature of medium in wireless networks makes it easy for adversary to launch a attack, especially jamming the beacon transmission,which seriously affects the performance of VANET.Therefore,this paper con-structed the model of platooning,and proposed a real-time detection jamming-beacon-transmission scheme.In this scheme,it divided time for transmission beacon into independent time slot.In the way that beacons from different groups never collided, it reduced the probability of interference with beacon.Finally,in view of the two types of attack types were simulated.The simulation results show that the proposed detection attack scheme has good performance,the initial detecting time is less than 150 ms,the average detection rate is not less than 0.9.In the case of two jammers,FNR is less than 0.15,the average FPR is less than 0.2.

  11. Detection of jamming transmission of beacon in vehicular networks%VANETs 中 beacon 的传输攻击实时检测算法

    Institute of Scientific and Technical Information of China (English)

    陈丹; 彭利民

    2015-01-01

    车载自组织网(vehicular Ad hoc networks,VANETs)中的车辆通过周期交互 beacon 实现信息共享,从而提高交通安全,然而 VANETs 无线网络特性系统易遭受多类攻击,特别是对 beacon 的传输攻击,即干扰 beacon的传输,其严重影响 VANETs 的安全性能。为此,建立车队 platooning 模型,提出实时检测干扰 beacon 传输的攻击方案。该方案首先将节点 beacon 传输时间分为相互独立的时隙,并依据此时隙将车辆分为不同的群,使得群间的 beacon 彼此不碰撞,从而降低 beacon 被干扰的概率。最后,针对两类攻击类型进行仿真。仿真结果表明,提出的检测攻击方案具有良好的性能,初始检测时间小于150 ms,平均检测率不低于0.9。在两个干扰者的情况下,漏警率小于0.15,平均的虚警率小于0.2。%The cooperation between the vehicles in the VANET is achieved by the frequent exchange of periodic broadcast messages carrying information on vehicle position and velocity,which is referred to as beacons,which is in favor of improving the security of VANET.However,the nature of medium in wireless networks makes it easy for adversary to launch a attack, especially jamming the beacon transmission,which seriously affects the performance of VANET.Therefore,this paper con-structed the model of platooning,and proposed a real-time detection jamming-beacon-transmission scheme.In this scheme,it divided time for transmission beacon into independent time slot.In the way that beacons from different groups never collided, it reduced the probability of interference with beacon.Finally,in view of the two types of attack types were simulated.The simulation results show that the proposed detection attack scheme has good performance,the initial detecting time is less than 150 ms,the average detection rate is not less than 0.9.In the case of two jammers,FNR is less than 0.15,the average FPR is less than 0.2.

  12. Serum inverts and improves the fluorescence response of an aptamer beacon to various vitamin D analytes.

    Science.gov (United States)

    Bruno, John G; Carrillo, Maria P; Phillips, Taylor; Edge, Allison

    2012-01-01

    A dominant aptamer loop structure from a library of nearly 100 candidate aptamer sequences developed against immobilized 25-hydroxyvitamin D(3) (calcidiol) was converted into a 5'-TYE 665 and 3'-Iowa black-labelled aptamer beacon. The aptamer beacon exhibited a mild 'lights on' reaction in buffer as a function of increasing concentrations of several vitamin D analogues and metabolites, with a limit of detection of approximately 200 ng/mL, and was not specific for any particular congener. In 10% or 50% human serum, the same aptamer beacon inverted its fluorescence behaviour to become a more intense 'lights off' reaction with an improved limit of detection in the range 4-16 ng/mL. We hypothesized that this drastic change in fluorescence behaviour was due to the presence of creatinine and urea in serum, which might destabilize the quenched beacon, causing an increase in fluorescence followed by decreasing fluorescence as a function of vitamin D concentrations that may bind and quench increasingly greater fractions of the denatured beacons. However, the results of several control experiments in the presence of physiological or greater concentrations of creatinine and urea, alone or combined in buffer, failed to produce the beacon fluorescence inversion. Other possible mechanistic hypotheses are also discussed.

  13. WSN中信标节点移动情况下的定位方法研究%Research on Localization Algorithm with Beacon Movement in Wireless Sensor Network

    Institute of Scientific and Technical Information of China (English)

    何文秀; 夏明; 赵小敏; 程荣; 陈庆章

    2011-01-01

    Localization is one of the basic theories and key technologies in wireless sensor network (WSN). However, in practical applications , the locations of some beacons would change due to various reasons after deployment, which leads to other unknown nodes rely on these beacons can not been accurately located. In order to solve the localization problems with beacons movement, this paper proposed an area division based beacon movement detection algorithm (AD-BMD), through two judgment processes to determine which beacon have moved, and set a coordinates confidence value for each beacon. In order to use moving beacons and unmoving beacons more reasonably, this paper also proposed a beacon movement detection based beacon optimal selection localization algorithm (BMD-BOS), through selecting beacons reasonably to calculate the position of unknown nodes. Experiment results show that AD-BMD has high correct rate and low error rate. Compared with LB and SSV, AD-BMD has better performance. The localization accuracy of BMD-BOS is much higher than N-BMD's and D-BMD's.%定位技术是无线传感器网络的基础理论和关键技术之一.在实际应用中,一些信标节点在部署以后其位置由于各种原因而会发生漂移,由此就使得依赖于这些信标节点来定位的其他节点将无法准确定位,或者产生很大定位误差.本文针对信标节点产生漂移情况下的节点定位问题,提出了一种基于区域划分的信标节点移动检测算法(AD-BMD),在区域划分的基础上,通过两次判定过程将移动的信标节点检测出来,并为每个信标设置了坐标可信度值.为合理利用移动的和未移动的信标节点,提出一种基于信标移动检测的信标择优定位算法(BMD-BOS),通过合理选择信标节点来对其它未知节点进行定位.实验结果证明,AD-BMD算法具有很高的检测正确率和较低错误率,检测效果好于LB和SSV方法.BMD-BOS算法的定位精度远远高于没有进行移

  14. Real-Time Nucleic Acid Sequence-Based Amplification Using Molecular Beacons for Detection of Enterovirus RNA in Clinical Specimens

    OpenAIRE

    Landry, Marie L.; Garner, Robin; Ferguson, David

    2005-01-01

    Real-time nucleic acid sequence-based amplification (NASBA) using molecular beacon technology (NASBA-beacon) was compared to standard NASBA with postamplification hybridization using electrochemiluminescently labeled probes (NASBA-ECL) for detection of enteroviruses (EV) in 133 cerebrospinal fluid and 27 stool samples. NASBA-ECL and NASBA-beacon were similar in sensitivity, detecting 55 (100%) and 52 (94.5%) EV-positive samples, respectively. There were no false positives. Both NASBA assays w...

  15. Location-aware sign-on and key exchange using attribute-based encryption and Bluetooth beacons

    OpenAIRE

    Portnoi, Marcos; Shen, Chien-Chung

    2015-01-01

    This work presents a mobile sign-on scheme, which utilizes Bluetooth Low Energy beacons for location awareness and Attribute-Based Encryption for expressive, broadcast-style key exchange. Bluetooth Low Energy beacons broadcast encrypted messages with encoded access policies. Within range of the beacons, a user with appropriate attributes is able to decrypt the broadcast message and obtain parameters that allow the user to perform a short or simplified login. The effect is a "traveling" sign-o...

  16. Improving adaptive optical systems by the use of multiple laser beacon configurations

    Science.gov (United States)

    de La Rue, Imelda Atencio

    The field of adaptive optics (AO) and laser-beacon AO has been successfully implemented in the last part of the 20th century. Adaptive optics greatly improves the resolution capabilities of ground-based telescopes by correcting for atmospheric turbulence. The initial implementation of laser-beacon AO was done on relatively small telescopes, on the order of 1.5 m. However, with larger aperture telescopes being built, such as the 8-m class Gemini telescopes, there is much room for improvement. Errors resulting from laser-beacon AO, such as focus anisoplanatism, become worse with an increase in aperture diameter. Tilt anisoplanatism is also a problem, regardless of the size of telescope, and also needs to be reduced to enhance the resolution of the objects being observed. This dissertation investigates alternate laser-beacon AO configurations, to reduce the effects of focus and tilt anisoplanatism for larger aperture telescopes. The configurations investigated include single and multiple laser beacons at single altitudes and single and multiple laser beacons at multiple altitudes. These second configurations are referred to as hybrid beacon systems and consist of Rayleigh beacons at altitudes of 10 to 20˜km and sodium beacons at about 90˜km, the location of the sodium layer. Hybrid systems are shown to reduce both focus and tilt anisoplanatism as opposed to the first configurations which only aid in reducing focus anisoplanatism. An addition to the hybrid systems with multiple beacons, the use of multiple deformable mirrors (DM's) is investigated. These additional DM's are placed conjugate to atmospheric altitudes with predominant turbulence, beyond the traditional conjugate location of the primary mirror. They correct for turbulence at these atmospheric layers and are referred to as multi-conjugate adaptive optical (MCAO) systems. The purpose of MCAO configurations is to increase the corrected field of view. For the types of systems investigated in this

  17. Beacon Hill end moraine, Boston: new explanation of an important urban feature

    Science.gov (United States)

    Kaye, Clifford A.; Coates, Donald R.

    1976-01-01

    The usefulness of geology to engineers is in direct proportion to how well it helps us predict the subsurface; these predictions, in turn, depend on our knowledge of the geomorphic processes that molded the terrain. The uncertainties of interpretation are particularly great in glaciated terrain because our understanding of both glacial processes and history is so incomplete, a fact well illustrated in Beacon Hill. Recent construction activities in the eastern part of the hill, until now classified as a drumlin, have shown that it is better interpreted as an end moraine formed by a Wisconsonian glacial readvance. Instead of the firm till that was anticipated as foundation material, excavations exposed a complex of sand, gravel, and clay, with only minor zones of till. The structure of these deposits strongly suggests that originally they were plates of the glacial bed that froze to the glacier and were transported englacially. Thrust faulting and other deformations are glacial structures formed within the ice in the glacier's terminal zone. In spite of the complex englacial history, these deposits lost little of their original appearance and intergranular relationships. Upon deglaciation, the frozen moraine thawed, and slumping formed complex secondary structures on the ridge's lower flanks.

  18. Quantum dot-based molecular beacon to monitor intracellular microRNAs.

    Science.gov (United States)

    Lee, Jonghwan; Moon, Sung Ung; Lee, Yong Seung; Ali, Bahy A; Al-Khedhairy, Abdulaziz A; Ali, Daoud; Ahmed, Javed; Al Salem, Abdullah M; Kim, Soonhag

    2015-06-02

    Fluorescence monitoring of endogenous microRNA (miRNA or miR) activity related to neuronal development using nano-sized materials provides crucial information on miRNA expression patterns in a noninvasive manner. In this study, we report a new method to monitor intracellular miRNA124a using quantum dot-based molecular beacon (R9-QD-miR124a beacon). The R9-QD-miR124a beacon was constructed using QDs and two probes, miR124a-targeting oligomer and arginine rich cell-penetrating peptide (R9 peptide). The miR124a-targeting oligomer contains a miR124a binging sequence and a black hole quencher 1 (BHQ1). In the absence of target miR124a, the R9-QD-miR124a beacon forms a partial duplex beacon and remained in quenched state because the BHQ1 quenches the fluorescence signal of the R9-QD-miR124a beacon. The binding of miR124a to the miR124a binding sequence of the miR124a-targeting oligomer triggered the separation of the BHQ1 quencher and subsequent signal-on of a red fluorescence signal. Moreover, enhanced cellular uptake was achieved by conjugation with the R9 peptide, which resulted in increased fluorescent signal of the R9-QD-miR124a beacons in P19 cells during neurogenesis due to the endogenous expression of miR124a.

  19. A molecular beacon biosensor based on the nanostructured aluminum oxide surface.

    Science.gov (United States)

    Che, Xiangchen; He, Yuan; Yin, Haocheng; Que, Long

    2015-10-15

    A new class of molecular beacon biosensors based on the nanostructured aluminum oxide or anodic aluminum oxide (AAO) surface is reported. In this type of sensor, the AAO surface is used to enhance the fluorescent signals of the fluorophore-labeled hairpin DNA. When a target DNA with a complementary sequence to that of the hairpin DNA is applied on the sensor, the fluorophores are forced to move away from the AAO surface due to the hybridization between the hairpin DNA and the target DNA, resulting in the significant decrease of the fluorescent signals. The observed signal reduction is sufficient to achieve a demonstrated detection limit of 10nM, which could be further improved by optimizing the AAO surface. The control experiments have also demonstrated that the bioassay used in the experiments has excellent specificity and selectivity, indicating the great promise of this type of sensor for diagnostic applications. Since the arrayed AAO micropatterns can be fabricated on a single chip in a cost-effective manner, the arrayed sensors could provide an ideal technical platform for studying fundamental biological process and monitoring disease biomarkers.

  20. Comparison of COMPARE and BEACON subcompartment analyses of Battelle-Frankfurt containment tests

    International Nuclear Information System (INIS)

    This report presents the results of computations performed with the COMPARE/MOD1 and BEACON/MOD3 computer codes for selected Battelle-Frankfurt loss-of-coolant accident experiments. COMPARE is used widely to perform nuclear power plant containment subcompartment analyses, and BEACON is an advanced multiphase, multidimensional best-estimate code. The objective of this study was to evaluate the margins of COMPARE calculations by comparing them with BEACON calculations and test data. The calculations were performed for the Battelle-Frankfurt D3, D6, and C9 tests. Descriptions of the two codes and the Battelle-Frankfurt experiments are included. Comparisons of the codes' calculations and experimental data for absolute pressure, differential pressure, and temperature are presented for margin evaluation. Evaluations of the sensitivity of BEACON calculations to variations in model noding, form loss, and vent area modeling are prsesented. Conclusions summarizing the results of the COMPARE margin evaluation and BEACON sensitivity studies are given as well

  1. Energy-Efficient BOP-Based Beacon Transmission Scheduling in Wireless Sensor Networks

    Science.gov (United States)

    Kim, Eui-Jik; Youm, Sungkwan; Choi, Hyo-Hyun

    Many applications in wireless sensor networks (WSNs) require the energy efficiency and scalability. Although IEEE 802.15.4/Zigbee which is being considered as general technology for WSNs enables the low duty-cycling with time synchronization of all the nodes in network, it still suffer from its low scalability due to the beacon frame collision. Recently, various algorithms to resolve this problem are proposed. However, their manners to implement are somewhat ambiguous and the degradation of energy/communication efficiency is serious by the additional overhead. This paper describes an Energy-efficient BOP-based Beacon transmission Scheduling (EBBS) algorithm. EBBS is the centralized approach, in which a resource-sufficient node called as Topology Management Center (TMC) allocates the time slots to transmit a beacon frame to the nodes and manages the active/sleep schedules of them. We also propose EBBS with Adaptive BOPL (EBBS-AB), to adjust the duration to transmit beacon frames in every beacon interval, adaptively. Simulation results show that by using the proposed algorithm, the energy efficiency and the throughput of whole network can be significantly improved. EBBS-AB is also more effective for the network performance when the nodes are uniformly deployed on the sensor field rather than the case of random topologies.

  2. Quencher-free molecular beacon tethering 7-hydroxycoumarin detects targets through protonation/deprotonation.

    Science.gov (United States)

    Kashida, Hiromu; Yamaguchi, Kyohei; Hara, Yuichi; Asanuma, Hiroyuki

    2012-07-15

    In this study, we synthesized a simple but efficient quencher-free molecular beacon tethering 7-hydroxycoumarin on D-threoninol based on its pK(a) change. The pK(a) of 7-hydroxycoumarin in a single strand was determined as 8.8, whereas that intercalated in the duplex was over 10. This large pK(a) shift (more than 1.2) upon hybridization could be attributed to the anionic and hydrophobic microenvironment inside the DNA duplex. Because 7-hydroxycoumarin quenches its fluorescence upon protonation, the emission intensity of the duplex at pH 8.5 was 1/15 that of the single strand. We applied this quenching mechanism to the preparation of a quencher-free molecular beacon by introducing the dye into the middle of the stem part. In the absence of the target, the stem region formed a duplex and fluorescence was quenched. However, when the target was added, the molecular beacon opened and the dye was deprotonated. As a result, the emission intensity of the molecular beacon with the target was 10 times higher than that without the target. Accordingly, a quencher-free molecular beacon utilizing the pK(a) change was successfully developed.

  3. A dual molecular beacon approach for fast detection of Mycobacterium tuberculosis.

    Science.gov (United States)

    Yu, Chuan-Xing; Zhao, Zi-Yun; Lv, Jian-Xin; Zhu, Ling

    2013-02-01

    The main objectives of this study were to assess a dual molecular beacon approach for fast detection of Mycobacterium tuberculosis (MT). MT beacon (Tb-B) was designed to target the unique IS6110 (114 bp) and rpoB (215 bp) fragment of the MT (H37Ra) genome, and the two fragments were inserted into the PMD-19T vector after purification, by PCR and sequencing, to construct plasmids. Different dilutions of positive plasmid standards were used for dual molecular beacon RT-PCR of rpoB and IS6110, and standard curves were established.The results show that the dual molecular beacon of rpoB and IS6110 detecting MT was stable (CV is 1.91-2.68 %) with a high amplification efficiency (95.6 %). In addition, the strains of non MT did not generate fluorescence signals, while strains of MT did, indicating that the primers and molecular beacons were specific, and only MT complex was amplified. The linear range was wide (10(3)-10(11) copies/mL), and clinical specimens presenting different bacterial counts can be detected.

  4. A spiral wave front beacon for underwater navigation: transducer prototypes and testing.

    Science.gov (United States)

    Dzikowicz, Benjamin R; Hefner, Brian T

    2012-05-01

    Transducers for acoustic beacons which can produce outgoing signals with wave fronts whose horizontal cross sections are circular or spiral are studied experimentally. A remote hydrophone is used to determine its aspect relative to the transducers by comparing the phase of the circular signal to the phase of the spiral signal. The transducers for a "physical-spiral" beacon are made by forming a strip of 1-3 piezocomposite transducer material around either a circular or spiral backing. A "phased-spiral" beacon is made from an array of transducer elements which can be driven either in phase or staggered out of phase so as to produce signals with either a circular or spiral wave front. Measurements are made to study outgoing signals and their usefulness in determining aspect angle. Vertical beam width is also examined and phase corrections applied when the hydrophone is out of the horizontal plane of the beacon. While numerical simulations indicate that the discontinuity in the physical-spiral beacon introduces errors into the measured phase, damping observed at the ends of the piezocomposite material is a more significant source of error. This damping is also reflected in laser Doppler vibrometer measurements of the transducer's surface velocity.

  5. Real-time quantitative nicking endonuclease-mediated isothermal amplification with small molecular beacons.

    Science.gov (United States)

    Xu, Wentao; Wang, Chenguang; Zhu, Pengyu; Guo, Tianxiao; Xu, Yuancong; Huang, Kunlun; Luo, Yunbo

    2016-04-21

    Techniques of isothermal amplification have recently made great strides, and have generated significant interest in the field of point-of-care detection. Nicking endonuclease-mediated isothermal amplification (NEMA) is an example of simple isothermal technology. In this paper, a real-time quantitative nicking endonuclease-mediated isothermal amplification with small molecular beacons (SMB-NEMA) of improved specificity and sensitivity is described. First, we optimized the prohibition of de novo synthesis by choosing Nt·BstNBI endonuclease. Second, the whole genome was successfully amplified with Nt·BstNBI (6 U), betaine (1 M) and trehalose (60 mM) for the first time. Third, we achieved 10 pg sensitivity for the first time after adding a small molecular beacon that spontaneously undergoes a conformational change when hybridizing to target, and the practical test validated the assay's application. The small molecular beacon has a similar melting temperature to the reaction temperature, but is approximately 10 bp shorter than the length of a traditional molecular beacon. A new threshold regulation was also established for isothermal conditions. Finally, we established a thermodynamic model for designing small molecular beacons. This multistate model is more correct than the traditional algorithm. This theoretical and practical basis will help us to monitor SMB-NEMA in a quantitative way. In summary, our SMB-NEMA method allows the simple, specific and sensitive assessment of isothermal DNA quantification. PMID:27027375

  6. First tests of wavefront sensing with a constellation of laser guide beacons

    CERN Document Server

    Lloyd-Hart, M; Milton, N M; Stalcup, T; Snyder, M; Putnam, N; Angel, J R P

    2005-01-01

    Adaptive optics to correct current telescopes over wide fields, or future very large telescopes over even narrow fields, will require real-time wavefront measurements made with a constellation of laser beacons. Here we report the first such measurements, made at the 6.5 m MMT with five Rayleigh beacons in a 2 arcmin pentagon. Each beacon is made with a pulsed beam at 532 nm, of 4 W at the exit pupil of the projector. The return is range-gated from 20-29 km and recorded at 53 Hz by a 36-element Shack-Hartmann sensor. Wavefronts derived from the beacons are compared with simultaneous wavefronts obtained for individual natural stars within or near the constellation. Observations were made in seeing averaging 1.0 arcsec with 2/3 of the aberration measured to be from a ground layer of mean height 380 m. Under these conditions, subtraction of the simple instantaneous average of the five beacon wavefronts from the stellar wavefronts yielded a 40% rms reduction in the measured modes of the distortion over a 2 arcmin ...

  7. An Elegant Biosensor Molecular Beacon Probe: Challenges and Recent Solutions

    Directory of Open Access Journals (Sweden)

    Dmitry M. Kolpashchikov

    2012-01-01

    Full Text Available Molecular beacon (MB probes are fluorophore- and quencher-labeled short synthetic DNAs folded in a stem-loop shape. Since the first report by Tyagi and Kramer, it has become a widely accepted tool for nucleic acid analysis and triggered a cascade of related developments in the field of molecular sensing. The unprecedented success of MB probes stems from their ability to detect specific DNA or RNA sequences immediately after hybridization with no need to wash out the unbound probe (instantaneous format. Importantly, the hairpin structure of the probe is responsible for both the low fluorescent background and improved selectivity. Furthermore, the signal is generated in a reversible manner; thus, if the analyte is removed, the signal is reduced to the background. This paper highlights the advantages of MB probes and discusses the approaches that address the challenges in MB probe design. Variations of MB-based assays tackle the problem of stem invasion, improve SNP genotyping and signal-to-noise ratio, as well as address the challenges of detecting folded RNA and DNA.

  8. STEREO Space Weather and the Space Weather Beacon

    Science.gov (United States)

    Biesecker, D. A.; Webb, D F.; SaintCyr, O. C.

    2007-01-01

    The Solar Terrestrial Relations Observatory (STEREO) is first and foremost a solar and interplanetary research mission, with one of the natural applications being in the area of space weather. The obvious potential for space weather applications is so great that NOAA has worked to incorporate the real-time data into their forecast center as much as possible. A subset of the STEREO data will be continuously downlinked in a real-time broadcast mode, called the Space Weather Beacon. Within the research community there has been considerable interest in conducting space weather related research with STEREO. Some of this research is geared towards making an immediate impact while other work is still very much in the research domain. There are many areas where STEREO might contribute and we cannot predict where all the successes will come. Here we discuss how STEREO will contribute to space weather and many of the specific research projects proposed to address STEREO space weather issues. We also discuss some specific uses of the STEREO data in the NOAA Space Environment Center.

  9. 75 FR 20364 - Public Buildings Service; Key Largo Beacon Annex Site; Key Largo, FL; Transfer of Property

    Science.gov (United States)

    2010-04-19

    ... From the Federal Register Online via the Government Publishing Office GENERAL SERVICES ADMINISTRATION Public Buildings Service; Key Largo Beacon Annex Site; Key Largo, FL; Transfer of Property..., identified as Key Largo Beacon Annex Site, Key Largo, FL to the U.S. Fish and Wildlife Service, Department...

  10. A molecular beacon-based DNA switch for reversible pH sensing in vesicles and live cells.

    Science.gov (United States)

    Narayanaswamy, Nagarjun; Nair, Raji R; Suseela, Y V; Saini, Deepak Kumar; Govindaraju, T

    2016-07-01

    In this Communication, a molecular beacon-based DNA switch (LMB) is developed as an efficient and reversible pH sensing probe. Remarkably, LMB exhibited reversible structural transition between the closed (molecular beacon) and open (A-motif) states very efficiently in synthetic vesicles and live cells without the need for any transfection agents.

  11. A molecular beacon-based DNA switch for reversible pH sensing in vesicles and live cells.

    Science.gov (United States)

    Narayanaswamy, Nagarjun; Nair, Raji R; Suseela, Y V; Saini, Deepak Kumar; Govindaraju, T

    2016-07-01

    In this Communication, a molecular beacon-based DNA switch (LMB) is developed as an efficient and reversible pH sensing probe. Remarkably, LMB exhibited reversible structural transition between the closed (molecular beacon) and open (A-motif) states very efficiently in synthetic vesicles and live cells without the need for any transfection agents. PMID:27338808

  12. Kontextbaserad information genom iBeacon : En implementation i iOS och Android

    OpenAIRE

    Älveborn, Andreas; Lönnerstrand, Marcus

    2014-01-01

    I dagsläget växer behovet av rätt information vid rätt plats, kontextbaserad information. Med hjälp av iBeacon kan man till en stor utsträckning förse det här behovet med en lösning. I uppsatsen undersöks användningsområden för iBeacon och idéer för hur man kan utveckla lösningar med hjälp av iBeacon. Ett koncept kommer att implementeras för att distribuera kontextbaserad information på mässor. Konceptet utvecklades till iOS och Android. Applikationerna tar hjälp av en webbtjänst för att unde...

  13. Visual detection of Akt mRNA in living cell using gold nanoparticle beacon

    Science.gov (United States)

    Ma, Yi; Tian, Caiping; Li, Siwen; Wang, Zhaohui; Gu, Yueqing

    2014-09-01

    PI3K-Akt signaling pathway plays the key role in cell apoptosis and survival, and the components of PI3K /Akt signaling pathway are often abnormally expressed in human tumors. Therefore, determination of the Akt (protein kinase B, PKB) messenger ribonucleic acid (mRNA) expression is significantly important in understanding the mechanism of tumor progression. In this study, we designed a special hairpin deoxyribonucleic acid (DNA) functionalized with gold nanoparticles and fluorescein isothiocyanate(FITC) as a beacon for detecting human Akt mRNA. Spectrofluorometer was used to detect the fluorescence quenching and recovery of the beacons, and laser confocal scanning microscopy was adopted to image Akt mRNA in cells. The results showed that this beacon could sensitively and quantitatively measure the Akt mRNA in living cells . This strategy is potentially useful for the cellular imaging of RNA or protein expression in living cells.

  14. A beacon interval shifting scheme for interference mitigation in body area networks.

    Science.gov (United States)

    Kim, Seungku; Kim, Seokhwan; Kim, Jin-Woo; Eom, Doo-Seop

    2012-01-01

    This paper investigates the issue of interference avoidance in body area networks (BANs). IEEE 802.15 Task Group 6 presented several schemes to reduce such interference, but these schemes are still not proper solutions for BANs. We present a novel distributed TDMA-based beacon interval shifting scheme that reduces interference in the BANs. A design goal of the scheme is to avoid the wakeup period of each BAN coinciding with other networks by employing carrier sensing before a beacon transmission. We analyze the beacon interval shifting scheme and investigate the proper back-off length when the channel is busy. We compare the performance of the proposed scheme with the schemes presented in IEEE 802.15 Task Group 6 using an OMNeT++ simulation. The simulation results show that the proposed scheme has a lower packet loss, energy consumption, and delivery-latency than the schemes of IEEE 802.15 Task Group 6.

  15. A spiral wave front beacon for underwater navigation: basic concept and modeling.

    Science.gov (United States)

    Hefner, Brian T; Dzikowicz, Benjamin R

    2011-06-01

    A spiral wave front source produces an acoustic field that has a phase that is proportional to the azimuthal angle about the source. The concept of a spiral wave front beacon is developed by combining this source with a reference source that has a phase that is constant with the angle. The phase difference between these sources contains information about the receiver's azimuthal angle relative to the beacon and can be used for underwater navigation. To produce the spiral wave front, two sources are considered: a "physical-spiral" source, which produces the appropriate phase by physically deforming the active element of the source into a spiral, and a "phased-spiral" source, which uses an array of active elements, each driven with the appropriate phase, to produce the spiral wave front. Using finite element techniques, the fields produced by these sources are examined in the context of the spiral wave front beacon, and the advantages of each source are discussed.

  16. Results from the northern New Mexico satellite-beacon radio interferometer

    International Nuclear Information System (INIS)

    An interferometer described in the Boston, 1992, meeting of the Beacon Satellite Symposium has been in full operation for over a year now. It consists of four autonomous stations; three are in a triangle 70 km on a side and one is in the center. The stations receive the VHF beacons from two geosynchronous satellites, GOES-2 and ATS-3. The phases of the beacons are tracked at each station by referring them to an extremely stable rubidium oscillator. The studies of the two satellites are virtually separate experiments. The received phase of the beacon is retarded by the increased Total-Electron-Content of the dense regions of waves in the ionosphere. By comparing the phase history at four spatially separated stations, the authors can determine the two-dimensional propagation vector of the waves. This array is optimal for wavelengths of 70--300 km (periods of 300--3,000 seconds). Since the measurement is of the phase of the signal rather than the difference between the O-mode and X-mode phases, and since the beacons are in the VHF rather than in the L-band of GPS beacons, the array is very sensitive. It has a noise level of 1013 electrons/m2, or 10-4 of the normal daytime TEC. This has been verified by operating two stations in the same location, so that they saw the same ionosphere. The first interesting results from a year's study is that the authors do not see the same TID's when looking at the two satellites. One conclusion they draw is that they do not see evidence of ionospheric winds

  17. Development of an aptamer beacon for detection of interferon-gamma.

    Science.gov (United States)

    Tuleuova, Nazgul; Jones, Caroline N; Yan, Jun; Ramanculov, Erlan; Yokobayashi, Yohei; Revzin, Alexander

    2010-03-01

    Traditional antibody-based affinity sensing strategies employ multiple reagents and washing steps and are unsuitable for real-time detection of analyte binding. Aptamers, on the other hand, may be designed to monitor binding events directly, in real-time, without the need for secondary labels. The goal of the present study was to design an aptamer beacon for fluorescence resonance energy transfer (FRET)-based detection of interferon-gamma (IFN-gamma)--an important inflammatory cytokine. Variants of DNA aptamer modified with biotin moieties and spacers were immobilized on avidin-coated surfaces and characterized by surface plasmon resonance (SPR). The SPR studies showed that immobilization of aptamer via the 3' end resulted in the best binding IFN-gamma (K(d) = 3.44 nM). This optimal aptamer variant was then used to construct a beacon by hybridizing fluorophore-labeled aptamer with an antisense oligonucleotide strand carrying a quencher. SPR studies revealed that IFN-gamma binding with an aptamer beacon occurred within 15 min of analyte introduction--suggesting dynamic replacement of the quencher-complementary strand by IFN-gamma molecules. To further highlight biosensing applications, aptamer beacon molecules were immobilized inside microfluidic channels and challenged with varying concentration of analyte. Fluorescence microscopy revealed low fluorescence in the absence of analyte and high fluorescence after introduction of IFN-gamma. Importantly, unlike traditional antibody-based immunoassays, the signal was observed directly upon binding of analyte without the need for multiple washing steps. The surface immobilized aptamer beacon had a linear range from 5 to 100 nM and a lower limit of detection of 5 nM IFN-gamma. In conclusion, we designed a FRET-based aptamer beacon for monitoring of an inflammatory cytokine-IFN-gamma. In the future, this biosensing strategy will be employed to monitor dynamics of cytokine production by the immune cells.

  18. Experience and evaluation of advanced on-line core monitoring system 'BEACON' at IKATA site

    International Nuclear Information System (INIS)

    Shikoku Electric Power Company installed BEACON core monitoring system into IKATA unit 3 in May 1994. During its first cycle of core operation, various operational data were obtained including data of some anomalous reactor conditions introduced for the test objective of the plant start-up. This paper presents the evaluation of the BEACON system capability based on this experience. The system functions such as core monitoring and anomaly detection, prediction of future reactor conditions and increased efficiency of core management activities are discussed. Our future plan to utilize the system is also presented. (authors)

  19. Beacon Hill Village in Boston: Ein erfolgreiches Beispiel einer Mitgliederorganisation auf Quartiersebene

    OpenAIRE

    Osl, Philipp; Benz, Alain; Österle, Hubert

    2011-01-01

    Beacon Hill Village erbringt und koordiniert als Intermediär ein breites Spektrum von Dienstleistungen für ältere Menschen in Boston. Durch Kombination professioneller Dienstleister und Freiwilligenarbeit sowie alternative Preismodelle für finanzschwache Mitglieder ist es der Organisation gelungen, ein an den Kundenbedürfnissen orientiertes Angebot für (fast) alle Menschen zugänglich zu machen. Der Beitrag stellt das Geschäftsmodell von Beacon Hill Village vor und diskutiert die Umsetzbarkeit...

  20. A transfection reporter for the prevention of false-negative results in molecular beacon experiments.

    Science.gov (United States)

    Toga, Tatsuya; Kuraoka, Isao; Yasui, Akira; Iwai, Shigenori

    2013-09-01

    We previously developed a molecular beacon-type probe to detect the strand scission in cellular base excision repair and found that the phosphodiester linkages in the fluorophore/quencher linkers were cleaved. This reaction was applied to a transfection reporter, which contained the unmodified phosphodiester in the linker to another type of fluorophore. After cotransfection of cells with the probe and the reporter, the signals were used to detect the incision and to confirm the proper transfection, respectively. This method will contribute to the prevention of false-negative results in experiments using molecular beacon-type probes.

  1. Visual detection of STAT5B gene expression in living cell using the hairpin DNA modified gold nanoparticle beacon.

    Science.gov (United States)

    Xue, Jianpeng; Shan, Lingling; Chen, Haiyan; Li, Yang; Zhu, Hongyan; Deng, Dawei; Qian, Zhiyu; Achilefu, Samuel; Gu, Yueqing

    2013-03-15

    Signal transducer and activator of transcription 5B (STAT5B) is an important protein in JAK-STAT signaling pathway that is responsible for the metastasis and proliferation of tumor cells. Determination of the STAT5B messenger Ribonucleic Acid (mRNA) relating to the STAT5B expression provides insight into the mechanism of tumor progression. In this study, we designed and used a special hairpin deoxyribonucleic acid (DNA) for human STAT5B mRNA to functionalize gold nanoparticles, which served as a beacon for detecting human STAT5B expression. Up to 90% quenching efficiency was achieved. Upon hybridizing with the target mRNA, the hairpin DNA modified gold nanoparticle beacons (hDAuNP beacons) release the fluorophores attached at 5' end of the oligonucleotide sequence. The fluorescence properties of the beacon before and after the hybridization with the complementary DNA were confirmed in vitro. The stability of hDAuNP beacons against degradation by DNase I and GSH indicated that the prepared beacon is stable inside cells. The detected fluorescence in MCF-7 cancer cells correlates with the specific STAT5B mRNA expression, which is consistent with the result from PCR measurement. Fluorescence microscopy showed that the hDAuNP beacons internalized in cells without using transfection agents, with intracellular distribution in the cytoplasm rather than the nucleus. The results demonstrated that this beacon could directly provide quantitative measurement of the intracellular STAT5B mRNA in living cells. Compared to the previous approaches, this beacon has advantages of higher target to background ratio of detection and an increased resistance to nuclease degradation. The strategy reported in this study is a promising approach for the intracellular measurement of RNA or protein expression in living cells, and has great potential in the study of drug screening and discovery.

  2. Genotyping Single Nucleotide Polymorphisms Using Different Molecular Beacon Multiplexed within a Suspended Core Optical Fiber

    Directory of Open Access Journals (Sweden)

    Linh Viet Nguyen

    2014-08-01

    Full Text Available We report a novel approach to genotyping single nucleotide polymorphisms (SNPs using molecular beacons in conjunction with a suspended core optical fiber (SCF. Target DNA sequences corresponding to the wild- or mutant-type have been accurately recognized by immobilizing two different molecular beacons on the core of a SCF. The two molecular beacons differ by one base in the loop-probe and utilize different fluorescent indicators. Single-color fluorescence enhancement was obtained when the immobilized SCFs were filled with a solution containing either wild-type or mutant-type sequence (homozygous sample, while filling the immobilized SCF with solution containing both wild- and mutant-type sequences resulted in dual-color fluorescence enhancement, indicating a heterozygous sample. The genotyping was realized amplification-free and with ultra low-volume for the required DNA solution (nano-liter. This is, to our knowledge, the first genotyping device based on the combination of optical fiber and molecular beacons.

  3. Aplicació de seguiment i visualització de dispositus iBeacon

    OpenAIRE

    Salvador Santiago, Rubén

    2015-01-01

    Els beacons són dispositius que emeten senyal bluetooth low energy (BLE) de manera contínua durant un llarg període de temps. Aquesta jove i emergent tecnologia esta cridada a ser una revolució en molts camps de la nostra vida diària.

  4. Standard and AEGIS nicking molecular beacons detect amplicons from the Middle East respiratory syndrome coronavirus.

    Science.gov (United States)

    Yaren, Ozlem; Glushakova, Lyudmyla G; Bradley, Kevin M; Hoshika, Shuichi; Benner, Steven A

    2016-10-01

    This paper combines two advances to detect MERS-CoV, the causative agent of Middle East Respiratory Syndrome, that have emerged over the past few years from the new field of "synthetic biology". Both are based on an older concept, where molecular beacons are used as the downstream detection of viral RNA in biological mixtures followed by reverse transcription PCR amplification. The first advance exploits the artificially expanded genetic information systems (AEGIS). AEGIS adds nucleotides to the four found in standard DNA and RNA (xNA); AEGIS nucleotides pair orthogonally to the A:T and G:C pairs. Placing AEGIS components in the stems of molecular beacons is shown to lower noise by preventing unwanted stem invasion by adventitious natural xNA. This should improve the signal-to-noise ratio of molecular beacons operating in complex biological mixtures. The second advance introduces a nicking enzyme that allows a single target molecule to activate more than one beacon, allowing "signal amplification". Combining these technologies in primers with components of a self-avoiding molecular recognition system (SAMRS), we detect 50 copies of MERS-CoV RNA in a multiplexed respiratory virus panel by generating fluorescence signal visible to human eye and/or camera. PMID:27421627

  5. BEACON - An advanced continuous core monitoring and operational support system for pressurized water reactors

    International Nuclear Information System (INIS)

    An advanced continuous core monitoring and operational support system, BEACON, has been developed which combines a super fast nodal model, workstation based hardware, and existing instrumentation which can be used to improve plant availability and operating margin. (author). 6 refs, 8 figs

  6. Application of the BEACON-TSM system to the operation of PWR reactors

    International Nuclear Information System (INIS)

    BEACON-TSM is an advanced system of the operation support of PWR reactors that combines the capabilities of an advanced nodal neutronic model and the measures of the instrumentation available in plant to determine, accurately and continuously, the distribution of power in the core and the available margins to the limits of the beak factors.

  7. Some measurements of total electron content made with the ATS-6 radio beacon

    International Nuclear Information System (INIS)

    The paper deals with some measurements made with the radio beacon on board the ATS-6 satellite in the American and European sectors. Measurements of the slant electron content, the Faraday content, and the plasmaspheric (or residual) content, made under different geographic and geomagnetic conditions, are discussed and compared

  8. Beacon satellite studies and modelling of total electron contents of the ionosphere

    International Nuclear Information System (INIS)

    An attempt is made to highlight some of the beacon satellite studies, particularly those relating to total electron content (TEC) and scintillations, with special attention to Indian subcontinent observations. The modelling of TEC is described. The scope of new experiments for specific problem is indicated. (author). 78 refs., 12 figs

  9. Beacon signal in transcranial color coded ultrasound: A sign for brain death

    OpenAIRE

    Mehmet Akif Topçuoğlu; Ethem Murat Arsava

    2014-01-01

    A widely under-recognized brain-death confirming transcranial ultrasonography pattern resembling the red-blue beacon signal was demonstrated. Familiarity to this distinct and characteristic ultrasonic pattern seems to be important in the perspective of point-of-care neurological ultrasound use and knobology.

  10. Analysis of Cluster Interconnection Schemes in 802.15.4 Beacon Enabled Networks

    OpenAIRE

    Jelena Mišić; Ranjith Udayshankar

    2008-01-01

    In this paper, we consider the interconnection of IEEE 802.15.4 beacon enabled network clusters. We discuss two types of interconnections. One type can be achieved by using the PAN coordinator node as the bridging device and the other type is achieved by using ordinary network nodes as bridge nodes. We discuss design and performance issues of both kinds of interconnections.

  11. Impacts of Fog Characteristics, Forward Illumination, and Warning Beacon Intensity Distribution on Roadway Hazard Visibility

    Science.gov (United States)

    2016-01-01

    Warning beacons are critical for the safety of transportation, construction, and utility workers. These devices need to produce sufficient luminous intensity to be visible without creating glare to drivers. Published standards for the photometric performance of warning beacons do not address their performance in conditions of reduced visibility such as fog. Under such conditions light emitted in directions other than toward approaching drivers can create scattered light that makes workers and other hazards less visible. Simulations of visibility of hazards under varying conditions of fog density, forward vehicle lighting, warning beacon luminous intensity, and intensity distribution were performed to assess their impacts on visual performance by drivers. Each of these factors can influence the ability of drivers to detect and identify workers and hazards along the roadway in work zones. Based on the results, it would be reasonable to specify maximum limits on the luminous intensity of warning beacons in directions that are unlikely to be seen by drivers along the roadway, limits which are not included in published performance specifications. PMID:27314058

  12. A nanocluster beacon based on the template transformation of DNA-templated silver nanoclusters.

    Science.gov (United States)

    Teng, Ye; Jia, Xiaofang; Zhang, Shan; Zhu, Jinbo; Wang, Erkang

    2016-01-28

    In this work, we developed a novel light-up nanocluster beacon (NCB) based on shuttling dark silver nanoclusters (NCs) to a bright scaffold through hybridization. The fluorescence enhancement was as high as 70-fold when the two templates were on the opposite sides of the duplexes, enabling sensitive and selective detection of DNA. PMID:26666564

  13. Reliable beacon transmission based MAC protocol for LR-WPANs over WLAN interferences

    Institute of Scientific and Technical Information of China (English)

    Ji-Hoon PARK; Byung-Seo KIM

    2014-01-01

    The use of IEEE 802.15.4 standard based application systems has been rapidly increasing, for example, in medical services, sensor networks, public safety systems, and home automation systems. However, issues arise from the fact that IEEE 802.15.4 standard based low rate wireless personal area networks (LR-WPANs) use the same frequency bands as wireless local area networks (WLANs), and they interfere with each other. Based on past research on this issue, the interference has a more serious impact on LR-WPANs’ performance than on WLANs’ performance. In this paper we propose a method to improve LR-WPANs’ performance while coexisting with WLANs, which is called the reliable beacon transmission based medium access control (MAC) protocol. Since the reliability of a beacon frame is important, in this method, only the beacon frame is transmitted in interference-free channels, and the data packets are transmitted in interfered channels instead of abandoning the channels altogether. This method increases the reliability of beacon frames as well as overall channel utilizations. The effectiveness of the proposed method was evaluated through extensive simulations, and this paper proves that this method improves the performance of IEEE 802.15.4 based wireless sensor networks (WSNs) over WLANs’ interferences.

  14. Molecular beacon nanosensors for live cell detection and tracking differentiation and reprogramming

    DEFF Research Database (Denmark)

    Ilieva, Mirolyuba

    2013-01-01

    cell level is molecular beacons (MBs). They are stem-loop structured antisense oligonucleotide probes labelled with a reporter fluorophore at one end and with quencher at the other end. Upon hybridization with complementary target, hydrogen bonds between stem nucleotide bases brake, resulting...

  15. Analysis and Enhancement of IEEE 802.15.4e DSME Beacon Scheduling Model

    Directory of Open Access Journals (Sweden)

    Kwang-il Hwang

    2014-01-01

    Full Text Available In order to construct a successful Internet of things (IoT, reliable network construction and maintenance in a sensor domain should be supported. However, IEEE 802.15.4, which is the most representative wireless standard for IoT, still has problems in constructing a large-scale sensor network, such as beacon collision. To overcome some problems in IEEE 802.15.4, the 15.4e task group proposed various different modes of operation. Particularly, the IEEE 802.15.4e deterministic and synchronous multichannel extension (DSME mode presents a novel scheduling model to solve beacon collision problems. However, the DSME model specified in the 15.4e draft does not present a concrete design model but a conceptual abstract model. Therefore, in this paper we introduce a DSME beacon scheduling model and present a concrete design model. Furthermore, validity and performance of DSME are evaluated through experiments. Based on experiment results, we analyze the problems and limitations of DSME, present solutions step by step, and finally propose an enhanced DSME beacon scheduling model. Through additional experiments, we prove the performance superiority of enhanced DSME.

  16. Beacon signal in transcranial color coded ultrasound: A sign for brain death

    Directory of Open Access Journals (Sweden)

    Mehmet Akif Topçuoğlu

    2014-04-01

    Full Text Available A widely under-recognized brain-death confirming transcranial ultrasonography pattern resembling the red-blue beacon signal was demonstrated. Familiarity to this distinct and characteristic ultrasonic pattern seems to be important in the perspective of point-of-care neurological ultrasound use and knobology.

  17. Sequential strand displacement beacon for detection of DNA coverage on functionalized gold nanoparticles.

    Science.gov (United States)

    Paliwoda, Rebecca E; Li, Feng; Reid, Michael S; Lin, Yanwen; Le, X Chris

    2014-06-17

    Functionalizing nanomaterials for diverse analytical, biomedical, and therapeutic applications requires determination of surface coverage (or density) of DNA on nanomaterials. We describe a sequential strand displacement beacon assay that is able to quantify specific DNA sequences conjugated or coconjugated onto gold nanoparticles (AuNPs). Unlike the conventional fluorescence assay that requires the target DNA to be fluorescently labeled, the sequential strand displacement beacon method is able to quantify multiple unlabeled DNA oligonucleotides using a single (universal) strand displacement beacon. This unique feature is achieved by introducing two short unlabeled DNA probes for each specific DNA sequence and by performing sequential DNA strand displacement reactions. Varying the relative amounts of the specific DNA sequences and spacing DNA sequences during their coconjugation onto AuNPs results in different densities of the specific DNA on AuNP, ranging from 90 to 230 DNA molecules per AuNP. Results obtained from our sequential strand displacement beacon assay are consistent with those obtained from the conventional fluorescence assays. However, labeling of DNA with some fluorescent dyes, e.g., tetramethylrhodamine, alters DNA density on AuNP. The strand displacement strategy overcomes this problem by obviating direct labeling of the target DNA. This method has broad potential to facilitate more efficient design and characterization of novel multifunctional materials for diverse applications.

  18. The Effects of a Rectangular Rapid-Flashing Beacon on Vehicle Speed

    Science.gov (United States)

    VanWagner, Michelle; Van Houten, Ron; Betts, Brian

    2011-01-01

    In 2008, nearly 31% of vehicle fatalities were related to failure to adhere to safe vehicle speeds (National Highway Traffic Safety Administration [NHTSA], 2009). The current study evaluated the effect of a rectangular rapid-flashing beacon (RRFB) triggered by excessive speed on vehicle speed using a combined alternating treatments and reversal…

  19. Leveraging Health IT to Reduce Disparities in Three Underserved Beacon Communities.

    Science.gov (United States)

    Des Jardins, Terrisca; Drone, Shenetta A; Hashisaka, Susan; Hazzard, Jobyna; Hunt, Susan B; Massey, Kimberly; Rein, Alison; Schachter, Abigail; Turske, Scott

    2016-01-01

    Using health information technology (IT) can potentially address health disparities by increasing access to care, delivering higher-quality care, improving patient-provider communication, and enhancing patient safety. It describes challenges encountered by three underserved Beacon Communities that implemented health IT interventions, including inadequate connectivity infrastructure, technical support, expertise, and financial resources; provider shortages and staff turnover; and equipment theft. PMID:27180682

  20. Impacts of Fog Characteristics, Forward Illumination, and Warning Beacon Intensity Distribution on Roadway Hazard Visibility.

    Science.gov (United States)

    Bullough, John D; Rea, Mark S

    2016-01-01

    Warning beacons are critical for the safety of transportation, construction, and utility workers. These devices need to produce sufficient luminous intensity to be visible without creating glare to drivers. Published standards for the photometric performance of warning beacons do not address their performance in conditions of reduced visibility such as fog. Under such conditions light emitted in directions other than toward approaching drivers can create scattered light that makes workers and other hazards less visible. Simulations of visibility of hazards under varying conditions of fog density, forward vehicle lighting, warning beacon luminous intensity, and intensity distribution were performed to assess their impacts on visual performance by drivers. Each of these factors can influence the ability of drivers to detect and identify workers and hazards along the roadway in work zones. Based on the results, it would be reasonable to specify maximum limits on the luminous intensity of warning beacons in directions that are unlikely to be seen by drivers along the roadway, limits which are not included in published performance specifications. PMID:27314058

  1. Stem-loop oligonucleotide beacons as switches for amplifying-fluorescent-polymer-based biological warfare sensors

    Science.gov (United States)

    Clinkenbeard, Kenneth D.; Ramachandran, Akhilesh; Malayer, Jerry R.; Moon, Joong Ho; Hancock, Lawrence F.

    2003-09-01

    Sensors that are exceptionally sensitive with real-time outputs and minimal consumption of reagents are needed to continuously monitor air and water against bioterrorist incidents. Amplifying fluorescent polymers (AFP) provide exceptionally sensitive real-time reagentless sensor platforms as applied to detection of nitroaromatic explosives. This platform technology has the potential to be adapted to detect biological warfare (BW) agents by covalently attaching the 5" end of stem-loop molecular beacons to AFP as DNA hybridization signal transduction switches. Molecular beacons with loop sequences specific for sequence signatures of a target BW agent are configured with a quencher on the end of the 3" arm of the stem-loop. The AFP is quenched in the absence of target DNA, but upon hybridization with target the stem is melted, the duplex loop extended, and the AFP dequenched. This signal transduction is reversible upon removal of the target sequence with the molecular beacon reforming the stem-loop conformation. Proof-of-concept research has demonstrated that molecular beacons for signature sequences of Francisella tularensis result in correct identification of the presence of this agent in samples, but no false positives were seen with Escherichia coli.

  2. Working Together To Build Beacon Centers in San Francisco: Evaluation Findings from 1998-2000.

    Science.gov (United States)

    Walker, Karen E.; Arbreton, Amy J. A.

    The Beacons Initiative aimed to transform eight public schools (five middle schools and three high schools) into youth and family centers in low-income neighborhoods in San Francisco, California. Using a coalition of local partners and funding from public agencies and foundations, the centers served 7,500 youth and adults between July 1, 1999, and…

  3. Scheduled MAC in Beacon Overlay Networks for Underwater Localization and Time-Synchronization

    NARCIS (Netherlands)

    Kleunen, van Wouter; Meratnia, Nirvana; Havinga, Paul J.M.

    2011-01-01

    In this article we introduce a MAC protocol designed for underwater localization and time-synchronisation. The MAC protocol assumes a network of static reference nodes and allows blind nodes to be localized by listening-only to the beacon messages. Such a system is known to be very scalable. We show

  4. Leveraging Health IT to Reduce Disparities in Three Underserved Beacon Communities.

    Science.gov (United States)

    Des Jardins, Terrisca; Drone, Shenetta A; Hashisaka, Susan; Hazzard, Jobyna; Hunt, Susan B; Massey, Kimberly; Rein, Alison; Schachter, Abigail; Turske, Scott

    2016-01-01

    Using health information technology (IT) can potentially address health disparities by increasing access to care, delivering higher-quality care, improving patient-provider communication, and enhancing patient safety. It describes challenges encountered by three underserved Beacon Communities that implemented health IT interventions, including inadequate connectivity infrastructure, technical support, expertise, and financial resources; provider shortages and staff turnover; and equipment theft.

  5. Impacts of Fog Characteristics, Forward Illumination, and Warning Beacon Intensity Distribution on Roadway Hazard Visibility.

    Science.gov (United States)

    Bullough, John D; Rea, Mark S

    2016-01-01

    Warning beacons are critical for the safety of transportation, construction, and utility workers. These devices need to produce sufficient luminous intensity to be visible without creating glare to drivers. Published standards for the photometric performance of warning beacons do not address their performance in conditions of reduced visibility such as fog. Under such conditions light emitted in directions other than toward approaching drivers can create scattered light that makes workers and other hazards less visible. Simulations of visibility of hazards under varying conditions of fog density, forward vehicle lighting, warning beacon luminous intensity, and intensity distribution were performed to assess their impacts on visual performance by drivers. Each of these factors can influence the ability of drivers to detect and identify workers and hazards along the roadway in work zones. Based on the results, it would be reasonable to specify maximum limits on the luminous intensity of warning beacons in directions that are unlikely to be seen by drivers along the roadway, limits which are not included in published performance specifications.

  6. A nanocluster beacon based on the template transformation of DNA-templated silver nanoclusters.

    Science.gov (United States)

    Teng, Ye; Jia, Xiaofang; Zhang, Shan; Zhu, Jinbo; Wang, Erkang

    2016-01-28

    In this work, we developed a novel light-up nanocluster beacon (NCB) based on shuttling dark silver nanoclusters (NCs) to a bright scaffold through hybridization. The fluorescence enhancement was as high as 70-fold when the two templates were on the opposite sides of the duplexes, enabling sensitive and selective detection of DNA.

  7. Rationally designed molecular beacons for bioanalytical and biomedical applications.

    Science.gov (United States)

    Zheng, Jing; Yang, Ronghua; Shi, Muling; Wu, Cuichen; Fang, Xiaohong; Li, Yinhui; Li, Jishan; Tan, Weihong

    2015-05-21

    Nucleic acids hold promise as biomolecules for future applications in biomedicine and biotechnology. Their well-defined structures and compositions afford unique chemical properties and biological functions. Moreover, the specificity of hydrogen-bonded Watson-Crick interactions allows the construction of nucleic acid sequences with multiple functions. In particular, the development of nucleic acid probes as essential molecular engineering tools will make a significant contribution to advancements in biosensing, bioimaging and therapy. The molecular beacon (MB), first conceptualized by Tyagi and Kramer in 1996, is an excellent example of a double-stranded nucleic acid (dsDNA) probe. Although inactive in the absence of a target, dsDNA probes can report the presence of a specific target through hybridization or a specific recognition-triggered change in conformation. MB probes are typically fluorescently labeled oligonucleotides that range from 25 to 35 nucleotides (nt) in length, and their structure can be divided into three components: stem, loop and reporter. The intrinsic merit of MBs depends on predictable design, reproducibility of synthesis, simplicity of modification, and built-in signal transduction. Using resonance energy transfer (RET) for signal transduction, MBs are further endowed with increased sensitivity, rapid response and universality, making them ideal for chemical sensing, environmental monitoring and biological imaging, in contrast to other nucleic acid probes. Furthermore, integrating MBs with targeting ligands or molecular drugs can substantially support their in vivo applications in theranositics. In this review, we survey advances in bioanalytical and biomedical applications of rationally designed MBs, as they have evolved through the collaborative efforts of many researchers. We first discuss improvements to the three components of MBs: stem, loop and reporter. The current applications of MBs in biosensing, bioimaging and therapy will then

  8. Supernova - the multi-dimensional core model of the Westinghouse on-line PWR core monitor, BEACON

    International Nuclear Information System (INIS)

    BEACON is an advanced multi-dimensional on-line PWR core monitoring system developed at Westinghouse. It resides on a workstation, and performs a large variety of very fast and accurate three-dimensional core analyses. The high speed performance of the BEACON system is made possible through the use of a superfast multi-dimensional nodal code, SUPERNOVA (SPNOVA), which is recently developed at Westinghouse. Compared to conventional nodal codes, SPNOVA is two orders of magnitude faster and yields predictions of comparable accuracy. This article describes the methodology of SPNOVA and presents examples of qualification data for both SPNOVA and BEACON

  9. Low cost high efficiency GaAs monolithic RF module for SARSAT distress beacons

    Science.gov (United States)

    Petersen, W. C.; Siu, D. P.; Cook, H. F.

    1991-12-01

    Low cost high performance (5 Watts output) 406 MHz beacons are urgently needed to realize the maximum utilization of the Search and Rescue Satellite-Aided Tracking (SARSAT) system spearheaded in the U.S. by NASA. Although current technology can produce beacons meeting the output power requirement, power consumption is high due to the low efficiency of available transmitters. Field performance is currently unsatisfactory due to the lack of safe and reliable high density batteries capable of operation at -40 C. Low cost production is also a crucial but elusive requirement for the ultimate wide scale utilization of this system. Microwave Monolithics Incorporated (MMInc.) has proposed to make both the technical and cost goals for the SARSAT beacon attainable by developing a monolithic GaAs chip set for the RF module. This chip set consists of a high efficiency power amplifier and a bi-phase modulator. In addition to implementing the RF module in Monolithic Microwave Integrated Circuit (MMIC) form to minimize ultimate production costs, the power amplifier has a power-added efficiency nearly twice that attained with current commercial technology. A distress beacon built using this RF module chip set will be significantly smaller in size and lighter in weight due to a smaller battery requirement, since the 406 MHz signal source and the digital controller have far lower power consumption compared to the 5 watt power amplifier. All the program tasks have been successfully completed. The GaAs MMIC RF module chip set has been designed to be compatible with the present 406 MHz signal source and digital controller. A complete high performance low cost SARSAT beacon can be realized with only additional minor iteration and systems integration.

  10. First Results for the TBB/CERTO Beacon Experiment on FORMOSAT- 3/COSMIC

    Science.gov (United States)

    Bernhardt, P. A.; Siefring, C. L.; Garner, T. W.; Gaussiran, T. L.; Secan, J.; Smith, F.; Groves, K.

    2006-12-01

    The Coherent Electromagnetic Radio Tomography (CERTO) instrument is a Tri-Band Beacon (TBB) that radiates unmodulated radio frequency carriers at 150.012, 400.032, and 1066.752 MHz. As part of the FORMOSAT-3 program, the six Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) satellites were launched in April 2006 with the TBB instrument along with a GPS occultation receiver (GOX) and a Tiny Ionospheric Photometer (TIP). Each of these instruments is capable of measuring integrated plasma density parameters for the F-region. The COSMIC satellites were initially deployed into 520 km orbits with 72 degrees inclination all in the same orbit plane. Each satellite will be boosted up to 800 km altitude with month-long time delays to allow separation of the orbits into six planes. Ground based receivers in Alaska, Virginia, Peru, and Kwajalein have recorded the radio beacon signals from the COSMIC CERTO beacons to determine the signal and antenna pattern specifications and to provide preliminary measurements of ionosphere TEC and radio scintillations. Because of power limitations and radio interference, TBB/CERTO frequency operations must be scheduled for passes over ground receivers. The ionospheric radio beacon data has been primarily obtained using the VHF and UHF CERTO frequencies. These data are complementary to ground based incoherent scatter radar (ISR) and ionosonde measurements as well as the GOX and TIP sensors on the satellites. Both tomography and inverse diffraction algorithms have been used to convert the radio beacon measurements into estimates of ionospheric electron density structures.

  11. Double-hairpin molecular-beacon-based amplification detection for gene diagnosis linked to cancer.

    Science.gov (United States)

    Xu, Huo; Zhang, Rongbo; Li, Feng; Zhou, Yingying; Peng, Ting; Wang, Xuedong; Shen, Zhifa

    2016-09-01

    A powerful double-hairpin molecular beacon (DHMB) was developed for cancer-related KRAS gene detection based on the one-to-two stoichiometry. During target DNA detection, DHMB can execute signal transduction even if no any exogenous element is involved. Unlike the conventional molecular beacon based on the one-to-one interaction, one target DNA not only hybridizes with one DHMB and opens its hairpin but also promotes the interaction between two DHMBs, causing the separation of two fluorophores from quenchers. This leads to an enhanced fluorescence signal. As a result, the target KRAS gene is able to be detected within a wide dynamic range from 0.05 to 200 nM with the detection limit of 50 pM, indicating a dramatic improvement compared with traditional molecular beacons. Moreover, the point mutations existing in target DNAs can be easily screened. The potential application for target species in real samples was indicated by the analysis of PCR amplicons of DNAs from the DNA extracted from SW620 cell. Besides becoming a promising candidate probe for molecular biology research and clinical diagnosis of genetic diseases, the DHMB is expected to provide a significant insight into the design of DNA probe-based homogenous sensing systems. Graphical Abstract A powerful double-hairpin molecular beacon (DHMB) was developed for cancer-related gene KRAS detection based on the one-to-two stoichiometry. Without the help of any exogenous probe, the point mutation is easily screened, and the target DNA can be quantified down to 50 pM, indicating a dramatic improvement compared with traditional molecular beacons.

  12. Double-hairpin molecular-beacon-based amplification detection for gene diagnosis linked to cancer.

    Science.gov (United States)

    Xu, Huo; Zhang, Rongbo; Li, Feng; Zhou, Yingying; Peng, Ting; Wang, Xuedong; Shen, Zhifa

    2016-09-01

    A powerful double-hairpin molecular beacon (DHMB) was developed for cancer-related KRAS gene detection based on the one-to-two stoichiometry. During target DNA detection, DHMB can execute signal transduction even if no any exogenous element is involved. Unlike the conventional molecular beacon based on the one-to-one interaction, one target DNA not only hybridizes with one DHMB and opens its hairpin but also promotes the interaction between two DHMBs, causing the separation of two fluorophores from quenchers. This leads to an enhanced fluorescence signal. As a result, the target KRAS gene is able to be detected within a wide dynamic range from 0.05 to 200 nM with the detection limit of 50 pM, indicating a dramatic improvement compared with traditional molecular beacons. Moreover, the point mutations existing in target DNAs can be easily screened. The potential application for target species in real samples was indicated by the analysis of PCR amplicons of DNAs from the DNA extracted from SW620 cell. Besides becoming a promising candidate probe for molecular biology research and clinical diagnosis of genetic diseases, the DHMB is expected to provide a significant insight into the design of DNA probe-based homogenous sensing systems. Graphical Abstract A powerful double-hairpin molecular beacon (DHMB) was developed for cancer-related gene KRAS detection based on the one-to-two stoichiometry. Without the help of any exogenous probe, the point mutation is easily screened, and the target DNA can be quantified down to 50 pM, indicating a dramatic improvement compared with traditional molecular beacons. PMID:27422649

  13. Ultra-Stable Beacon Source for Laboratory Testing of Optical Tracking

    Science.gov (United States)

    Aso, Yoichi; Marka, Szabolcs; Kovalik, Joseph

    2008-01-01

    The ultra-stable beacon source (USBS) provides a laser-beam output with a very low angular jitter and can be used as an absolute angular reference to simulate a beacon in the laboratory. The laser is mounted on the top of a very short (approximately equal to 1 m) inverted pendulum (IP) with its optical axis parallel to the carbon fiber pendulum leg. The 85-cm, carbon fiber rods making up the leg are very lightweight and rigid, and are supported by a flex-joint at the bottom (see figure). The gimbal-mounted laser is a weight-adjustable load of about 1.5 kg with its center of rotation co-located with the center of percussion of the inverted pendulum. This reduces the coupling of transverse motion at the base of the pendulum to angular motion of the laser at the top. The inverted pendulum is mounted on a gimbal with its center of rotation coinciding with the pivot position of the inverted pendulum flexure joint. This reduces coupling of ground tilt at the inverted pendulum base to motion of the laser mounted at the top. The mass of the top gimbal is adjusted to give the pendulum a very low resonant frequency (approximately equal to 10 mHz) that filters transverse seismic disturbances from the ground where the base is attached. The motion of the IP is monitored by an optical-lever sensor. The laser light is reflected by the mirror on the IP, and then is detected by a quadrant photo-detector (QPD). The position of the beam spot on the QPD corresponds to the tilt of the IP. Damping of this motion is provided by two coil and magnet pairs. The bottom gimbal mount consists of two plates. The IP is mounted on the second plate. The first plate is supported by two posts through needles and can be rotated about the axis connecting the tips of the needles. The second plate hangs from the first plate and can be rotated about the axis perpendicular to the first plate. As a result, the second plate acts as a two-axis rotation stage. Its center of rotation is located at the

  14. BEACON/MOD2A analysis of the Arkansas-1 reactor cavity during a hypothetical hot leg break

    International Nuclear Information System (INIS)

    As part of the evaluation of the new MOD2A version of the BEACON code, the Arkansas-1 reactor cavity was modeled during a hypothetical loss-of-coolant accident. Results of the BEACON analysis were compared with results obtained previously with the COMPARE containment code. Studies were also made investigating some of the BEACON interphasic, timestep control, and wall heat transfer options to assure that these models were working properly and to observe their effects on the results. Descriptions of the Arkansas-1 reactor cavity, initial assumptions during the hypothetical LOCA, and methods of modeling with BEACON are presented. Some of the problems encountered in accurately modeling the penetrations surrounding the hot and cold leg pipes are also discussed

  15. BEACON/MOD: a computer program for thermal-hydraulic analysis of nuclear reactor containments - user's manual

    International Nuclear Information System (INIS)

    The BEACON code is a best-estimate, advanced containment code designed to perform a best-estimate analysis of the flow of a mixture of air, water, and steam in a nuclear reactor containment system under loss-of-coolant accident conditions. The code can simulate two-component, two-phase fluid flow in complex geometries using a combination of two-dimensional, one-dimensional, and lumped-parameter representations for the various parts of the system. The current version of BEACON, which is designated BEACON/MOD3, contains mass and heat transfer models for wall film and wall conduction. It is suitable for the evaluation of short-term transients in dry-containment systems. This manual describes the models employed in BEACON/MOD3 and specifies code implementation requirements. It provides application information for input data preparation and for output data interpretation

  16. Triplex molecular beacons for sensitive recognition of melamine based on abasic-site-containing DNA and fluorescent silver nanoclusters.

    Science.gov (United States)

    Wang, Ya; Sun, Qianqian; Zhu, Linling; Zhang, Junying; Wang, Fengyang; Lu, Linlin; Yu, Haijun; Xu, Zhiai; Zhang, Wen

    2015-05-01

    A melamine aptamer derived from an abasic-site-containing triplex molecular beacon (tMB) was designed and developed for sensitive recognition of melamine by integrating tMBs and fluorescent silver nanoclusters (Ag NCs). PMID:25865656

  17. Improving the detectability of oxygen saturation level targets for preterm neonates: A laboratory test of tremolo and beacon sonifications.

    Science.gov (United States)

    Deschamps, Marie-Lys; Sanderson, Penelope; Hinckfuss, Kelly; Browning, Caitlin; Loeb, Robert G; Liley, Helen; Liu, David

    2016-09-01

    Recent guidelines recommend oxygen saturation (SpO2) levels of 90%-95% for preterm neonates on supplemental oxygen but it is difficult to discern such levels with current pulse oximetry sonifications. We tested (1) whether adding levels of tremolo to a conventional log-linear pulse oximetry sonification would improve identification of SpO2 ranges, and (2) whether adding a beacon reference tone to conventional pulse oximetry confuses listeners about the direction of change. Participants using the Tremolo (94%) or Beacon (81%) sonifications identified SpO2 range significantly more accurately than participants using the LogLinear sonification (52%). The Beacon sonification did not confuse participants about direction of change. The Tremolo sonification may have advantages over the Beacon sonification for monitoring SpO2 of preterm neonates, but both must be further tested with clinicians in clinically representative scenarios, and with different levels of ambient noise and distractions.

  18. Improving the detectability of oxygen saturation level targets for preterm neonates: A laboratory test of tremolo and beacon sonifications.

    Science.gov (United States)

    Deschamps, Marie-Lys; Sanderson, Penelope; Hinckfuss, Kelly; Browning, Caitlin; Loeb, Robert G; Liley, Helen; Liu, David

    2016-09-01

    Recent guidelines recommend oxygen saturation (SpO2) levels of 90%-95% for preterm neonates on supplemental oxygen but it is difficult to discern such levels with current pulse oximetry sonifications. We tested (1) whether adding levels of tremolo to a conventional log-linear pulse oximetry sonification would improve identification of SpO2 ranges, and (2) whether adding a beacon reference tone to conventional pulse oximetry confuses listeners about the direction of change. Participants using the Tremolo (94%) or Beacon (81%) sonifications identified SpO2 range significantly more accurately than participants using the LogLinear sonification (52%). The Beacon sonification did not confuse participants about direction of change. The Tremolo sonification may have advantages over the Beacon sonification for monitoring SpO2 of preterm neonates, but both must be further tested with clinicians in clinically representative scenarios, and with different levels of ambient noise and distractions. PMID:27184324

  19. 'Close-the-loop': an iBeacon app to foster recycling through just-in-time feedback

    OpenAIRE

    Casado-Mansilla, Diego; Foster, Derek; Lawson, Shaun; Garaizr, Pablo; López-de-Ipiña, Diego

    2015-01-01

    Contemporary micro-location technologies such as Bluetooth Low Energy (BLE) show promise in enabling new experiences when interacting with physical spaces. An emerging BLE technology is iBeacons, with the retail sector pioneering their use to enhance shopping experiences. There is scope for the HCI sustainability community to explore the use of iBeacons to raise awareness around sustainability issues, particularly in public and communal spaces. This work presents embryonic research exploring ...

  20. Implementation details of the time division beacon scheduling approach for ZigBee cluster-tree networks

    OpenAIRE

    Cunha, André; Alves, Mário; Koubâa, Anis

    2007-01-01

    This technical report describes the implementation details of the Time Division Beacon Scheduling Approach in IEEE 802.15.4/ZigBee Cluster-Tree Networks. In this technical report we describe the implementation details, focusing on some aspects of the ZigBee Network Layer and the Time Division Beacon Scheduling mechanism. This report demonstrates the feasibility of our approach based on the evaluation of the experimental results. We also present an overview of the ZigBee address an...

  1. Traveling-Wave Tube Amplifier Second Harmonic as Millimeter-Wave Beacon Source for Atmospheric Propagation Studies

    Science.gov (United States)

    Simons, Rainee N.; Wintucky, Edwin G.

    2014-01-01

    This paper presents the design and test results of a CW millimeter-wave satellite beacon source, based on the second harmonic from a traveling-wave tube amplifier and utilizes a novel waveguide multimode directional coupler. A potential application of the beacon source is for investigating the atmospheric effects on Q-band (37-42 GHz) and V/W-band (71- 76 GHz) satellite-to-ground signals.

  2. Improved margin utilization through the use of beacon power distribution surveillance

    International Nuclear Information System (INIS)

    Core Operations, including fuel cycle costs, can be significantly improved when state of the art surveillance techniques are employed for core power distribution monitoring. Core power distribution monitoring and Technical Specification surveillance are major operational issues at PWR's, particularly in plants with movable in core detectors. Even plants with fixed in core detectors do not always make use of the continuous data that is available. The BEACONTM system (Best Estimate Analysis of Core Operations - Nuclear) is a core monitoring and operational support package developed by Westinghouse for use in PWR plants with fixed or movable in core detectors. BEACON is a real time core monitoring system, which uses existing core instrumentation data and an on-line neutronics model to provide continuous monitored of the core power distribution information. With this information available the BEACON system can be used to continuously monitor core power margin for the plant Tech Spec surveillance requirements and for plant operational guidance

  3. A Telomerase-Specific Doxorubicin-Releasing Molecular Beacon for Cancer Theranostics.

    Science.gov (United States)

    Ma, Yi; Wang, Zhaohui; Zhang, Min; Han, Zhihao; Chen, Dan; Zhu, Qiuyun; Gao, Weidong; Qian, Zhiyu; Gu, Yueqing

    2016-03-01

    A molecular beacon-based drug delivery system was designed for both detection of telomerase activity in living cells and telomerase-triggered drug release for precise cancer treatment. This system is composed of a gold nanoparticle core densely packed with FITC-labeled hairpin DNA sequences hybridized with telomerase primers. Molecules of the anticancer drug doxorubicin were intercalated into the stem region of the DNA sequence. The presence of telomerase will elongate the primers, leading to inner chain substitution followed by the release of the FITC fluorescence and the trapped doxorubicin. This molecular beacon could specifically distinguish tumor cells and normal cells based on telomerase activity, precisely release doxorubicin in response to telomerase activity in the tumor cells, and prevent toxicity to normal organs. PMID:26848056

  4. Design of a K/Q-Band Beacon Receiver for the Alphasat TDP#5 Experiment

    Science.gov (United States)

    Morse, Jacquelynne R.

    2014-01-01

    This paper describes the design and performance of a coherent KQ-band (2040 GHz) beacon receiver developed at NASA Glenn Research Center (GRC) that will be installed at the Politecnico di Milano (POLIMI) for use in the Alphasat Technology Demonstration Payload 5 (TDP5) beacon experiment. The goal of this experiment is to characterize rain fade attenuation at 40 GHz to improve the performance of existing statistical rain attenuation models in the Q-band. The ground terminal developed by NASA GRC utilizes an FFT-based frequency estimation receiver capable of characterizing total path attenuation effects due to gaseous absorption, clouds, rain, and scintillation. The receiver system has been characterized in the lab and demonstrates a system dynamic range performance of better than 58 dB at 1 Hz and better than 48 dB at 10 Hz rates.

  5. Performance evaluation of beacon enabled IEEE 802.15.4 under NS2

    CERN Document Server

    Charfi, Faiza

    2012-01-01

    The increasing demand for real-time applications has made the Quality of Service (Qos) support for wireless sensor networks (WSN) a fairly new research framework. In this paper, we propose an extended model of the Beacon enabled IEEE 802.15.4 including the Guaranteed Time Slot GTS allocation mechanism in the aim to analyze and evaluate network performances. Series of extensive simulations were performed to analyze the impact of the Beacon Order BO and the Superframe Order SO on the network performance based on commonly known metrics. In particular, we examine data packet delivery performance and the throughput for different duty cycle rates. Also, we analyze the impact of the number of nodes on collision probability. Thus, for high number of nodes, collision becomes higher and the reachability begins to decline slightly. We discuss and compare simulation results conducted under various parameter settings to the IEEE 802.11 network.

  6. BEACON FRAME MANIPULATION TO MITIGATE ROGUE ACCESS POINTS: CASE OF ANDROID SMARTPHONE ROGUE ACCESS POINTS

    Directory of Open Access Journals (Sweden)

    Thambo Nyathi

    2015-11-01

    Full Text Available The use of wireless devices to access corporate network resources is now part of the norm within corporate environments. When wireless users need to connect to a network they hardly question the source of their connectivity. Mobile phones, particularly smartphones allow users to access network resources. These harmless looking wireless devices can be a source of major threats if configured to be so. The Internet is awash with mobile apps capable of performing packet sniffing. These applications, coupled with the capability of the smartphone to be configured as an access point, can present a Smartphone Rogue Access Point. Access Points advertise their availability using what is called a beacon frame. This research paper proposes a solution which restructures this beacon frame to include an Authentic Access Point Value which can be used to defend against Rogue Access Points.

  7. Multi-Band Multi-Tone Tunable Millimeter-Wave Frequency Synthesizer For Satellite Beacon Transmitter

    Science.gov (United States)

    Simons, Rainee N.; Wintucky, Edwin G.

    2016-01-01

    This paper presents the design and test results of a multi-band multi-tone tunable millimeter-wave frequency synthesizer, based on a solid-state frequency comb generator. The intended application of the synthesizer is in a satellite beacon transmitter for radio wave propagation studies at K-band (18 to 26.5 GHz), Q-band (37 to 42 GHz), and E-band (71 to 76 GHz). In addition, the architecture for a compact beacon transmitter, which includes the multi-tone synthesizer, polarizer, horn antenna, and power/control electronics, has been investigated for a notional space-to-ground radio wave propagation experiment payload on a small satellite. The above studies would enable the design of robust high throughput multi-Gbps data rate future space-to-ground satellite communication links.

  8. Performance Evaluation Of BEACON-ENABLED IEEE 802.15.4 Under NS2

    Directory of Open Access Journals (Sweden)

    Faiza Charfi

    2012-04-01

    Full Text Available The increasing demand for real-time applications has made the Quality of Service (Qos support for wireless sensor networks (WSN a fairly new research framework. In this paper, we propose an extended model of the Beacon enabled IEEE 802.15.4 including the Guaranteed Time Slot GTS allocation mechanism in the aim to analyze and evaluate network performances. Series of extensive simulations were performed to analyze the impact of the Beacon Order BO and the Superframe Order SO on the network performance based on commonly known metrics. In particular, we examine data packet delivery performance and the throughput for different duty cycle rates. Also, we analyze the impact of the number of nodes on collision probability. Thus, for high number of nodes, collision becomes higher and the reachability begins to decline slightly. We discuss and compare simulation results conducted under various parameter settings to the IEEE 802.11network.

  9. Nanosecond-level time synchronization of AERA using a beacon reference transmitter and commercial airplanes

    CERN Document Server

    Huege, Tim

    2016-01-01

    Radio detection of cosmic-ray air showers requires time synchronization of detectors on a nanosecond level, especially for advanced reconstruction algorithms based on the wavefront curvature and for interferometric analysis approaches. At the Auger Engineering Radio Array, the distributed, autonomous detector stations are time-synchronized via the Global Positioning System which, however, does not provide sufficient timing accuracy. We thus employ a dedicated beacon reference transmitter to correct for event-by-event clock drifts in our offline data analysis. In an independent cross-check of this "beacon correction" using radio pulses emitted by commercial airplanes, we have shown that the combined timing accuracy of the two methods is better than 2 nanoseconds.

  10. Beacon Frame Manipulation to Mitigate Rogue Access Points: Case of Android Smartphone Rogue Access Points

    Directory of Open Access Journals (Sweden)

    Thambo Nyathi

    2014-02-01

    Full Text Available The use of wireless devices to access corporate network resources is now part of the norm within corporate environments. When wireless users need to connect to a network they hardly question the source of their connectivity. Mobile phones, particularly smartphones allow users to access network resources. These harmless looking wireless devices can be a source of major threats if configured to be so. The Internet is awash with mobile apps capable of performing packet sniffing. These applications, coupled with the capability of the smartphone to be configured as an access point, can present a Smartphone Rogue Access Point. Access Points advertise their availability using what is called a beacon frame. This research paper proposes a solution which restructures this beacon frame to include an Authentic Access Point Value which can be used to defend against Rogue Access Points.

  11. A Telomerase-Specific Doxorubicin-Releasing Molecular Beacon for Cancer Theranostics.

    Science.gov (United States)

    Ma, Yi; Wang, Zhaohui; Zhang, Min; Han, Zhihao; Chen, Dan; Zhu, Qiuyun; Gao, Weidong; Qian, Zhiyu; Gu, Yueqing

    2016-03-01

    A molecular beacon-based drug delivery system was designed for both detection of telomerase activity in living cells and telomerase-triggered drug release for precise cancer treatment. This system is composed of a gold nanoparticle core densely packed with FITC-labeled hairpin DNA sequences hybridized with telomerase primers. Molecules of the anticancer drug doxorubicin were intercalated into the stem region of the DNA sequence. The presence of telomerase will elongate the primers, leading to inner chain substitution followed by the release of the FITC fluorescence and the trapped doxorubicin. This molecular beacon could specifically distinguish tumor cells and normal cells based on telomerase activity, precisely release doxorubicin in response to telomerase activity in the tumor cells, and prevent toxicity to normal organs.

  12. Topical MMP beacon enabled fluorescence-guided resection of oral carcinoma.

    Science.gov (United States)

    Burgess, Laura; Chen, Juan; Wolter, Nikolaus E; Wilson, Brian; Zheng, Gang

    2016-03-01

    Each year almost 300,000 individuals worldwide are diagnosed with oral cancer, more than 90% of these being oral carcinoma [N. Engl. J. Med.328, 1841993]. Surgical resection is the standard of care, but accurate delineation of the tumor boundaries is challenging, resulting in either under-resection with risk of local recurrence or over-resection with increased functional loss and negative impact on quality of life. This study evaluates, in two pre-clinical in vivo tumor models, the potential of fluorescence-guided resection using molecular beacons activated by metalloproteinases, which are frequently upregulated in human oral cancer. In both models there was rapid (beacon activation upon local application, allowing clear fluoresecence imaging in vivo and confirmed by ex vivo fluorescence microscopy and HPLC, with minimal activation in normal oral tissues. Although the tissue penetration was limited using topical application, these findings support further development of this approach towards translation to first-in-human trials. PMID:27231609

  13. Creation of a Library Tour Application for Mobile Equipment using iBeacon Technology

    Directory of Open Access Journals (Sweden)

    Jonathan Bradley

    2016-04-01

    Full Text Available We describe the design, development, and deployment of a library tour application utilizing Bluetooth Low Energy devices know as iBeacons. The tour application will serve as library orientation for incoming students. The students visit stations in the library with mobile equipment running a special tour app. When the app detects a beacon nearby, it automatically plays a video that describes the current location. After the tour, students are assessed according to the defined learning objectives. Special attention is given to issues encountered during development, deployment, content creation, and testing of this application that depend on functioning hardware, and the necessity of appointing a project manager to limit scope, define priorities, and create an actionable plan for the experiment.

  14. Topical MMP beacon enabled fluorescence-guided resection of oral carcinoma.

    Science.gov (United States)

    Burgess, Laura; Chen, Juan; Wolter, Nikolaus E; Wilson, Brian; Zheng, Gang

    2016-03-01

    Each year almost 300,000 individuals worldwide are diagnosed with oral cancer, more than 90% of these being oral carcinoma [N. Engl. J. Med.328, 1841993]. Surgical resection is the standard of care, but accurate delineation of the tumor boundaries is challenging, resulting in either under-resection with risk of local recurrence or over-resection with increased functional loss and negative impact on quality of life. This study evaluates, in two pre-clinical in vivo tumor models, the potential of fluorescence-guided resection using molecular beacons activated by metalloproteinases, which are frequently upregulated in human oral cancer. In both models there was rapid (beacon activation upon local application, allowing clear fluoresecence imaging in vivo and confirmed by ex vivo fluorescence microscopy and HPLC, with minimal activation in normal oral tissues. Although the tissue penetration was limited using topical application, these findings support further development of this approach towards translation to first-in-human trials.

  15. Initial Flight Results for an Automated Satellite Beacon Health Monitoring Network

    OpenAIRE

    Young, Anthony; Kitts, Christopher; Neumann, Michael; Mas, Ignacio; Rasay, Mike

    2010-01-01

    Beacon monitoring is an automated satellite health monitoring architecture that combines telemetry analysis, periodic low data rate message broadcasts by a spacecraft, and automated ground reception and data handling in order to implement a cost-effective anomaly detection and notification capability for spacecraft missions. Over the past two decades, this architecture has been explored and prototyped for a range of spacecraft mission classes to include use on NASA deep space probes, military...

  16. Increased dose near the skin due to electromagnetic surface beacon transponder.

    Science.gov (United States)

    Ahn, Kang-Hyun; Manger, Ryan; Halpern, Howard J; Aydogan, Bulent

    2015-01-01

    The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general-purpose Monte Carlo code MCNPX (Monte Carlo N-Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L-shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (~ 1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large-breasted women. PMID:26103472

  17. Anti-racist cultural politics in post-imperial Britain: the New Beacon Circle

    OpenAIRE

    Alleyne, Brian

    2007-01-01

    This chapter explores the activist-pedagogy of one group that sought to negotiate an inclusive place in Britain for the descendants of Black and Brown migrants: New Beacon Circle, based in North London, England. Whereas many contributors to this book have addressed contemporary alternative educational initiatives, I consider one that started in the mid-1960s and is still active today. In this way, I emphasize the continuity in radical experimentation in utopian pedagogy. In the case of New Be...

  18. Dynamic Omnidirectional Vision Localization Using a Beacon Tracker Based on Particle Filter

    OpenAIRE

    Cao, Zuoliang; Meng, Xianqiu; Liu, Shiyu

    2008-01-01

    We establish omni-directional vision system with fisheye lens and solve the problem of fisheye image distortion. A method for calibrating the omni-vision system is proposed to generate the center of a fisheye lens image. A novel fisheye image rectification algorithm based on SVM, which is different from the conventional method is introduced. Beacon recognition and tracking are key procedures for an omni-vision guided mobile unit. A Particle Filter (PF) has been shown to be successful for seve...

  19. Increased dose near the skin due to electromagnetic surface beacon transponder.

    Science.gov (United States)

    Ahn, Kang-Hyun; Manger, Ryan; Halpern, Howard J; Aydogan, Bulent

    2015-05-08

    The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general-purpose Monte Carlo code MCNPX (Monte Carlo N-Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L-shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (~ 1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large-breasted women.

  20. ENHANCED COMPOSITE APPROACH WITH MOBILE BEACON SHORTEST PATH TO SOLVE LOCALIZATION PROBLEM IN WIRELESS SENSOR NETWORK

    Directory of Open Access Journals (Sweden)

    Sunil Kumar,

    2010-12-01

    Full Text Available Wireless sensor network is tremendously being used in different environments to perform various monitoring task such as search, rescue, disaster relief, target tracking and a number of tasks in smart environment. In this paper a unique localization algorithm is proposed that gives the high accuracy in wireless sensor network. We propose amobile beacon algorithm and then merge it with DV- hop algorithm to introduce a unique approach which solves the localization problem in wireless sensor network.

  1. Developing children's palliative care in Africa through beacon centres: lessons learnt.

    Science.gov (United States)

    Downing, Julia D; Marston, Joan; Selwyn, Casey; Ross-Gakava, Laura

    2013-02-18

    Much progress has been made in the provision of palliative care across sub-Saharan Africa, however much still remains to be done, particularly in the area of children's palliative care (CPC). The Beacon Centres programme was set up in 2009, aimed at improving access to CPC in South Africa, Uganda and Tanzania through more and better-trained health professionals and CPC clinical services of a high standard. Having identified sites in each country to develop into CPC Beacon Centres, Navigators were identified who would be the 'champions' for CPC in those sites and lead a programme of training, mentorship and support. Five navigators (2 in Uganda and Tanzania and 1 in South Africa) were trained between September and December 2009. Following this they undertook CPC needs assessments at the 3 centres and set up and delivered a six-month CPC training programme, providing mentorship and support to students to enable them to integrate CPC into their workplaces. To date, 188 participants have commenced the six-month course, with 80 having completed it. CPC has been integrated into the activities of the centres and a CPC virtual resource centre set up in South Africa. The achievements from the Beacon project have been great and the work of the navigators immense, but as in all projects it has not been without its challenges. Lessons learnt include issues around: the focus of the project; the length and nature of the training; assessment; accreditation; the choice of navigators; mentoring; administrative support; co-ordination; the choice of project sites; and the integration of CPC into services. The need for CPC is not going to go away and it is therefore important that models of scaling-up are found that are not only practical, feasible, affordable and sustainable, but that focus on the outcome of improved CPC for all those who need it. It is hoped that the lessons shared from the Beacon Project will help in developing and implementing such models.

  2. A new class of SETI beacons that contain information (22-aug-2010)

    OpenAIRE

    Harp, G. R.; Ackermann, R. F.; Blair, Samantha K.; Arbunich, J.; Backus, P. R.; Tarter, J. C.; Team, the ATA

    2012-01-01

    In the cm-wavelength range, an extraterrestrial electromagnetic narrow band (sine wave) beacon is an excellent choice to get alien attention across interstellar distances because 1) it is not strongly affected by interstellar / interplanetary dispersion or scattering, and 2) searching for narrowband signals is computationally efficient (scales as Ns log(Ns) where Ns = number of voltage samples). Here we consider a special case wideband signal where two or more delayed copies of the same signa...

  3. Rapid determination of total hardness in water using fluorescent molecular aptamer beacon

    International Nuclear Information System (INIS)

    A double-labelled synthetic oligonucleotide is used as a fluorescent molecular aptamer beacon for the reagentless determination of total hardness in tap and bottled waters. Modified thrombin binding aptamer (5'-NH-C3-GGTTGGTGTGGTTGG-C3-SH-3') carrying 6-carboxyfluorescein (FAM) and 7-amino-4-methyl-coumarin labels at 5' and 3', respectively, was used for the simultaneous combined measurement of Mg2+ and Ca2+ cations. Interference from the K+ cation is eliminated via selective tuning of the assay conditions, increasing the temperature beyond the melting point of the potassium-stabilised quadruplex facilitating its liberation from the quadruplex, whilst maintaining the integrity of the magnesium/calcium-stabilised structure. No interference from other cations found in tap or bottled water was observed. The detection limit of the aptamer beacon is 0.04 mmol L-1, with a dynamic linear range of 0-0.5 μM and is very reproducible, with an R.S.D. = 8%, n = 3. The fluorescent molecular beacon is applied to the determination of total hardness in tap and bottled waters and its' performance compared to that of the standard method of complexiometric titration and atomic absorption spectroscopy, with an excellent correlation observed. Further work is focused on the immobilization of the aptamer for the development of a re-usable fluorescent/electrochemical aptasensor, for the determination of water hardness

  4. Beacon: A three-dimensional structural analysis code for bowing history of fast breeder reactor cores

    International Nuclear Information System (INIS)

    The core elements of an LMFBR are bowed due to radial gradients of both temperature and neutron flux in the core. Since all hexagonal elements are multiply supported by adjacent elements or the restraint system, restraint forces and bending stresses are induced. In turn, these forces and stresses are relaxed by irradiation enhanced creep of the material. The analysis of the core bowing behavior requires a three-dimensional consideration of the mechanical interactions among the core elements, because the core consists of different kinds of elements and of fuel assemblies with various burnup histories. A new computational code BEACON has been developed for analyzing the bowing behavior of an LMFBR's core in three dimensions. To evaluate mechanical interactions among core elements, the code uses the analytical method of the earlier SHADOW code. BEACON analyzes the mechanical interactions in three directions, which form angles of 600 with one another. BEACON is applied to the 600 sector of a typical LMFBR's core for analyzing the bowing history during one equilibrium cycle. 120 core elements are treated, assuming the boundary condition of rotational symmetry. The application confirms that the code can be an effective tool for parametric studies as well as for detailed structural analysis of LMFBR's core. (orig.)

  5. 增强型塔康信标天线%Enhancement-Mode TACAN Beaconing Antenna

    Institute of Scientific and Technical Information of China (English)

    史小鸣; 苟锋

    2015-01-01

    The operating range and measuring accuracy are directly influenced by TACAN beaconing antenna, currently TACAN beaconing antenna has the characters of modulation circuit loss and modulation pattern reduction and it may enlarge the transmitting power of ground equipment demand. A zero subsidence area exists within the covering range which is unable to measure. The two enhancement-mode TACAN beaconing antennas which use the receiving and sending beam separation theory are presented in this paper. They may effective improve and solve those problems.%塔康信标天线直接影响塔康系统的作用距离和测位精度.现有塔康信标天线存在调制电路损耗与调制方向图衰减等固有特性,造成地面设备需求的发射功率大,并且覆盖距离内往往存在无法测距的"零陷区".本文提出应用收、发波束分离原理的两种增强型塔康天线概念,可望有效改善或解决这些问题.

  6. Enhancement-Mode TACAN Beaconing Antenna%增强型塔康信标天线

    Institute of Scientific and Technical Information of China (English)

    史小鸣; 苟锋

    2015-01-01

    The operating range and measuring accuracy are directly influenced by TACAN beaconing antenna, currently TACAN beaconing antenna has the characters of modulation circuit loss and modulation pattern reduction and it may enlarge the transmitting power of ground equipment demand. A zero subsidence area exists within the covering range which is unable to measure. The two enhancement-mode TACAN beaconing antennas which use the receiving and sending beam separation theory are presented in this paper. They may effective improve and solve those problems.%塔康信标天线直接影响塔康系统的作用距离和测位精度.现有塔康信标天线存在调制电路损耗与调制方向图衰减等固有特性,造成地面设备需求的发射功率大,并且覆盖距离内往往存在无法测距的"零陷区".本文提出应用收、发波束分离原理的两种增强型塔康天线概念,可望有效改善或解决这些问题.

  7. A multistatic HF beacon network for ionospheric specification in the Peruvian sector

    Science.gov (United States)

    Hysell, D. L.; Milla, M. A.; Vierinen, J.

    2016-05-01

    A small network of HF beacon transmitters and receivers has been deployed in Peru for specifying the F region ionosphere in the sector. The effort is motivated by ionospheric disturbances associated with equatorial spread F (ESF) and specifically disturbances arising under inauspicious conditions for ESF as determined by numerical simulations. The beacons operate at dual frequencies (2.72 and 3.64 MHz). They are CW but incorporate pseudorandom noise (PRN) coding so that the group delays of the links can be measured. Other observables are power, Doppler shift, bearing, and polarization. A transmitter is currently deployed at Ancon (11°46'37''S, 77°09'1''W, 51 m above sea level (asl)), while receivers are at Jicamarca (11°57'5.8''S, 76°52'27''W, 510 m asl) and Huancayo (12°02'30''S, 75°19'15''W, 3315 m asl). An algorithm for inverting the beacon data combined with electron density profiles from Jicamarca is described. Data and representative solutions from an experimental campaign held in August 2015 are presented and evaluated.

  8. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe.

    Science.gov (United States)

    Zhang, Feng; Li, Shuangming; Cao, Kang; Wang, Pengjuan; Su, Yan; Zhu, Xinhua; Wan, Ying

    2015-06-11

    A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA) detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT), gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS) microfluidic channels. DNA aptamer, or "artificial antibody", was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the "aptamer beacon", highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  9. Rapid determination of total hardness in water using fluorescent molecular aptamer beacon

    Energy Technology Data Exchange (ETDEWEB)

    Lerga, T. Mairal [Nanobiotechnology and Bioanalysis Group, Department of Chemical Engineering, Universitat Rovira I Virgili (Spain); O' Sullivan, Ciara K. [Nanobiotechnology and Bioanalysis Group, Department of Chemical Engineering, Universitat Rovira I Virgili (Spain); Institucio Catalana de Recerca i Estudis Avancats, Passeig Lluis Companys 23, 08010 Barcelona (Spain)], E-mail: ciara.osullivan@urv.net

    2008-03-03

    A double-labelled synthetic oligonucleotide is used as a fluorescent molecular aptamer beacon for the reagentless determination of total hardness in tap and bottled waters. Modified thrombin binding aptamer (5'-NH-C3-GGTTGGTGTGGTTGG-C3-SH-3') carrying 6-carboxyfluorescein (FAM) and 7-amino-4-methyl-coumarin labels at 5' and 3', respectively, was used for the simultaneous combined measurement of Mg{sup 2+} and Ca{sup 2+} cations. Interference from the K{sup +} cation is eliminated via selective tuning of the assay conditions, increasing the temperature beyond the melting point of the potassium-stabilised quadruplex facilitating its liberation from the quadruplex, whilst maintaining the integrity of the magnesium/calcium-stabilised structure. No interference from other cations found in tap or bottled water was observed. The detection limit of the aptamer beacon is 0.04 mmol L{sup -1}, with a dynamic linear range of 0-0.5 {mu}M and is very reproducible, with an R.S.D. = 8%, n = 3. The fluorescent molecular beacon is applied to the determination of total hardness in tap and bottled waters and its' performance compared to that of the standard method of complexiometric titration and atomic absorption spectroscopy, with an excellent correlation observed. Further work is focused on the immobilization of the aptamer for the development of a re-usable fluorescent/electrochemical aptasensor, for the determination of water hardness.

  10. Selective amyloid β oligomer assay based on abasic site-containing molecular beacon and enzyme-free amplification.

    Science.gov (United States)

    Zhu, Linling; Zhang, Junying; Wang, Fengyang; Wang, Ya; Lu, Linlin; Feng, Chongchong; Xu, Zhiai; Zhang, Wen

    2016-04-15

    Amyloid-beta (Aβ) oligomers are highly toxic species in the process of Aβ aggregation and are regarded as potent therapeutic targets and diagnostic markers for Alzheimer's disease (AD). Herein, a label-free molecular beacon (MB) system integrated with enzyme-free amplification strategy was developed for simple and highly selective assay of Aβ oligomers. The MB system was constructed with abasic site (AP site)-containing stem-loop DNA and a fluorescent ligand 2-amino-5,6,7-trimethyl-1,8-naphyridine (ATMND), of which the fluorescence was quenched upon binding to the AP site in DNA stem. Enzyme-free amplification was realized by target-triggered continuous opening of two delicately designed MBs (MB1 and MB2). Target DNA hybridization with MB1 and then MB2 resulted in the release of two ATMND molecules in one binding event. Subsequent target recycling could greatly amplify the detection sensitivity due to the greatly enhanced turn-on emission of ATMND fluorescence. Combining with Aβ oligomers aptamers, the strategy was applied to analyze Aβ oligomers and the results showed that it could quantify Aβ oligomers with high selectivity and monitor the Aβ aggregation process. This novel method may be conducive to improve the diagnosis and pathogenic study of Alzheimer's disease. PMID:26613510

  11. Selective amyloid β oligomer assay based on abasic site-containing molecular beacon and enzyme-free amplification.

    Science.gov (United States)

    Zhu, Linling; Zhang, Junying; Wang, Fengyang; Wang, Ya; Lu, Linlin; Feng, Chongchong; Xu, Zhiai; Zhang, Wen

    2016-04-15

    Amyloid-beta (Aβ) oligomers are highly toxic species in the process of Aβ aggregation and are regarded as potent therapeutic targets and diagnostic markers for Alzheimer's disease (AD). Herein, a label-free molecular beacon (MB) system integrated with enzyme-free amplification strategy was developed for simple and highly selective assay of Aβ oligomers. The MB system was constructed with abasic site (AP site)-containing stem-loop DNA and a fluorescent ligand 2-amino-5,6,7-trimethyl-1,8-naphyridine (ATMND), of which the fluorescence was quenched upon binding to the AP site in DNA stem. Enzyme-free amplification was realized by target-triggered continuous opening of two delicately designed MBs (MB1 and MB2). Target DNA hybridization with MB1 and then MB2 resulted in the release of two ATMND molecules in one binding event. Subsequent target recycling could greatly amplify the detection sensitivity due to the greatly enhanced turn-on emission of ATMND fluorescence. Combining with Aβ oligomers aptamers, the strategy was applied to analyze Aβ oligomers and the results showed that it could quantify Aβ oligomers with high selectivity and monitor the Aβ aggregation process. This novel method may be conducive to improve the diagnosis and pathogenic study of Alzheimer's disease.

  12. Mega-nano detection of foodborne pathogens and transgenes using molecular beacon and semiconductor quantum dot technologies.

    Science.gov (United States)

    Burris, Kellie P; Wu, Tsai-Chin; Vasudev, Milana; Stroscio, Michael A; Millwood, Reginald J; Stewart, C Neal

    2013-09-01

    Signature molecules derived from Listeria monocytogenes, Bacillus thuringiensis, and Salmonella Typhimurium were detected directly on food substrates (mega) by coupling molecular beacon technology utilizing fluorescent resonance energy transfer (FRET), luminescent nanoscale semiconductor quantum dots, and nanoscale quenchers. We designed target DNA sequences for detecting hlyA, Bt cry1Ac, and invA genes from L. monocytogenes, B. thuringiensis and Salmonella Typhimurium, respectively, and prepared molecular beacons for specific targets for use in real-time monitoring. We successfully detected increased fluorescence in the presence of signature molecules at molecular beacon (MB) concentrations from 1.17 nM to 40 nM, depending upon system tested in (water, milk or plant leaves), respective target (hlyA, Bt cry1Ac, or invA) and genomic DNA target concentration (50-800 ng). We were able to detect bacterial genomic DNA derived from L. monocytogenes and Salmonella sp. in a food system, 2% milk ( > 20% of total volume). Furthermore, we infiltrated the Bt cry1Ac beacon in the presence of genomic DNA extracted from B. thuringiensis into Arabidopsis thaliana leaves and observed increased fluorescence in the presence of the target, indicating the ability to use these beacons in a plant system.

  13. Research on Beacon Hill School Education Practice%比肯山学校教育实践研究

    Institute of Scientific and Technical Information of China (English)

    张蔚

    2015-01-01

    比肯山学校是1927年由罗素夫妇创办的新式学校,罗素夫妇将他们的教育思想运用于实践。教育生态学、教育人类学、教育文化学和教育管理学等多学科的视角下对比肯山学校进行研究,从而考察比肯山学校所具有的历史价值。%Beacon Hill school is an new schools started by Russell couple on 1927. Russell couples are turning their ideas on education in practice. This article make an contrast study on Beacon Hill School from a multidisciplinary perspective of educational ecology, educational anthropology, science of culture and education management and so on, Thus investigate the historical value of the Beacon Hill school.

  14. Preliminary Results of the NASA Beacon Receiver for Alphasat Aldo Paraboni TDP5 Propagation Experiment

    Science.gov (United States)

    Nessel, James; Morse, Jacquelynne; Zemba, Michael; Riva, Carlo; Luini, Lorenzo

    2014-01-01

    NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 GHz band. NASA GRC has developed and installed a K/Q-band (20/40 GHz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20/40 GHz signals broadcast from the Alphasat Aldo Paraboni TDP#5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we describe the design and preliminary performance of the NASA propagation terminal, which has been installed and operating in Milan since May 2014. The receiver is based upon a validated Fast Fourier Transform (FFT) I/Q digital design approach utilized in other operational NASA propagation terminals, but has been modified to employ power measurement via a frequency estimation technique and to coherently track and measure the amplitude of the 20/40 GHz beacon signals. The system consists of a 1.2-m K-band and a 0.6-m Qband Cassegrain reflector employing synchronous open-loop tracking to track the inclined orbit of the Alphasat satellite. An 8 Hz sampling rate is implemented to characterize scintillation effects, with a 1-Hz measurement bandwidth dynamic range of 45 dB. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models.

  15. Performance of the NASA Beacon Receiver for the Alphasat Aldo Paraboni TDP5 Propagation Experiment

    Science.gov (United States)

    Nessel, James; Morse, Jacquelynne; Zemba, Michael; Riva, Carlo; Luini, Lorenzo

    2015-01-01

    NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 gigahertz band. NASA GRC has developed and installed a K/Q-band (20/40 gigahertz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20/40 gigahertz signals broadcast from the Alphasat Aldo Paraboni Technology Demonstration Payload (TDP) no. 5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we describe the design and preliminary performance of the NASA propagation terminal, which has been installed and operating in Milan since June 2014. The receiver is based upon a validated Fast Fourier Transform (FFT) I/Q digital design approach utilized in other operational NASA propagation terminals, but has been modified to employ power measurement via a frequency estimation technique and to coherently track and measure the amplitude of the 20/40 gigahertz beacon signals. The system consists of a 1.2-meter K-band and a 0.6-meter Q-band Cassegrain reflector employing synchronous open-loop tracking to track the inclined orbit of the Alphasat satellite. An 8 hertz sampling rate is implemented to characterize scintillation effects, with a 1-hertz measurement bandwidth dynamic range of 45 decibels. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models.

  16. Performance of beacon safety message dissemination in Vehicular Ad hoc NETworks (VANETs)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Currently, there is a growing belief that putting an IEEE 802.11-like radio into road vehicles can help the drivers to travel more safely. Message dissemination protocols are primordial for safety vehicular applications. There are two types of safety messages which may be exchanged between vehicles: alarm and beacon. In this paper we investigate the feasibility of deploying safety applications based on beacon message dissemination through extensive simulation study and pay special attention to the safety requirements. Vehicles are supposed to issue these messages periodically to announce to other vehicles their current situation and use received messages for preventing possible unsafe situations. We evaluate the performance of a single-hop dissemination protocol while taking into account the quality of service (QoS) metrics like delivery rate and delay. We realize that reliability is the main concern in beacon message dissemination. Thus, a new metric named effective range is defined which gives us more accurate facility for evaluating QoS in safety applications specifically. Then, in order to improve the performance, the effects of three parameters including vehicle's transmission range, message transmission's interval time and message payload size are studied. Due to special characteristics of the safety applications, we model the relationship between communication-level QoS and application-level QoS and evaluate them for different classes of safety applications. As a conclusion, the current technology of IEEE 802.11 MAC layer has still some challenges for automatic safety applications but it can provide acceptable QoS to driver assistance safety applications.

  17. A distance-dependent metal-enhanced fluorescence sensing platform based on molecular beacon design.

    Science.gov (United States)

    Zhou, Zhenpeng; Huang, Hongduan; Chen, Yang; Liu, Feng; Huang, Cheng Zhi; Li, Na

    2014-02-15

    A new metal-enhanced fluorescence (MEF) based platform was developed on the basis of distance-dependent fluorescence quenching-enhancement effect, which combined the easiness of Ag-thiol chemistry with the MEF property of noble-metal structures as well as the molecular beacon design. For the given sized AgNPs, the fluorescence enhancement factor was found to increase with a d(6) dependency in agreement with fluorescence resonance energy transfer mechanism at shorter distance and decrease with a d(-3) dependency in agreement with plasmonic enhancement mechanism at longer distance between the fluorophore and the AgNP surface. As a proof of concept, the platform was demonstrated by a sensitive detection of mercuric ions, using thymine-containing molecular beacon to tune silver nanoparticle (AgNP)-enhanced fluorescence. Mercuric ions were detected via formation of a thymine-mercuric-thymine structure to open the hairpin, facilitating fluorescence recovery and AgNP enhancement to yield a limit of detection of 1 nM, which is well below the U.S. Environmental Protection Agency regulation of the Maximum Contaminant Level Goal (10nM) in drinking water. Since the AgNP functioned as not only a quencher to reduce the reagent blank signal but also an enhancement substrate to increase fluorescence of the open hairpin when target mercuric ions were present, the quenching-enhancement strategy can greatly improve the detection sensitivity and can in principle be a universal approach for various targets when combined with molecular beacon design.

  18. Making it local: Beacon Communities use health information technology to optimize care management.

    Science.gov (United States)

    Allen, Amy; Des Jardins, Terrisca R; Heider, Arvela; Kanger, Chatrian R; Lobach, David F; McWilliams, Lee; Polello, Jennifer M; Rein, Alison L; Schachter, Abigail A; Singh, Ranjit; Sorondo, Barbara; Tulikangas, Megan C; Turske, Scott A

    2014-06-01

    Care management aims to provide cost-effective, coordinated, non-duplicative care to improve care quality, population health, and reduce costs. The 17 communities receiving funding from the Office of the National Coordinator for Health Information Technology through the Beacon Community Cooperative Agreement Program are leaders in building and strengthening their health information technology (health IT) infrastructure to provide more effective and efficient care management. This article profiles 6 Beacon Communities' health IT-enabled care management programs, highlighting the influence of local context on program strategy and design, and describing challenges, lessons learned, and policy implications for care delivery and payment reform. The unique needs (eg, disease burden, demographics), community partnerships, and existing resources and infrastructure all exerted significant influence on the overall priorities and design of each community's care management program. Though each Beacon Community needed to engage in a similar set of care management tasks--including patient identification, stratification, and prioritization; intervention; patient engagement; and evaluation--the contextual factors helped shape the specific strategies and tools used to carry out these tasks and achieve their objectives. Although providers across the country are striving to deliver standardized, high-quality care, the diverse contexts in which this care is delivered significantly influence the priorities, strategies, and design of community-based care management interventions. Gaps and challenges in implementing effective community-based care management programs include: optimizing allocation of care management services; lack of available technology tailored to care management needs; lack of standards and interoperability; integrating care management into care settings; evaluating impact; and funding and sustainability.

  19. Simultaneous and multiplexed detection of exosome microRNAs using molecular beacons.

    Science.gov (United States)

    Lee, Ji Hye; Kim, Jeong Ah; Jeong, Seunga; Rhee, Won Jong

    2016-12-15

    Simultaneous and multiplexed detection of microRNAs (miRNAs) in a whole exosome is developed, which can be utilized as a PCR-free efficient diagnosis method for various diseases. Exosomes are small extracellular vesicles that contain biomarker miRNAs from parental cells. Because they circulate throughout bodily fluids, exosomal biomarkers offer great advantages for diagnosis in many aspects. In general, PCR-based methods can be used for exosomal miRNA detection but they are laborious, expensive, and time-consuming, which make them unsuitable for high-throughput diagnosis of diseases. Previously, we reported that single miRNA in the exosomes can be detected specifically using an oligonucleotide probe or molecular beacon. Herein, we demonstrate for the first time that multiple miRNAs can be detected simultaneously in exosomes using miRNA-targeting molecular beacons. Exosomes from a breast cancer cell line, MCF-7, were used for the production of exosomes because MCF-7 has a high level of miR-21, miR-375, and miR-27a as target miRNAs. Molecular beacons successfully hybridized with multiple miRNAs in the cancer cell-derived exosomes even in the presence of high human serum concentration. In addition, it is noteworthy that the choice of fluorophores for multiplexing biomarkers in an exosome is crucial because of its small size. The proposed method described in this article is beneficial to high-throughput analysis for disease diagnosis, prognosis, and response to treatment because it is a time-, labor-, and cost-saving technique. PMID:27372573

  20. A mobile indoor positioning system based on iBeacon technology.

    Science.gov (United States)

    Lin, Xin-Yu; Ho, Te-Wei; Fang, Cheng-Chung; Yen, Zui-Shen; Yang, Bey-Jing; Lai, Feipei

    2015-01-01

    To increase the efficiency in the emergency room, the goal of this research is to implement a mobile-based indoor positioning system using mobile applications (APP) with the iBeacon solution based on the Bluetooth Low Energy (BLE) technology. We use the Received Signal Strength (RSS) based localization method to estimate the patients' locations. Our positioning algorithm achieves 97.22% (95% Confidence Interval = 95.90% - 98.55%) accuracy of classification. As the result, our mechanism is reliable enough to satisfy the need for medical staff to track the locations of their patients. PMID:26737407

  1. Tecnología iBeacon aplicada a la monitorización de clientes

    OpenAIRE

    Molinier Gómez, Adrián

    2015-01-01

    En el presente trabajo se desarrolla una aplicación para la monitorización de usuarios a través de la tecnología iBeacon de Apple. Este documento refleja las decisiones de diseño, funcionalidades y validaciones realizadas, tanto en el apartado de la aplicación móvil, como en el de la aplicación web, aportando finalmente una serie de valoraciones acerca de los resultados obtenidos y sobre el desarrollo del trabajo en general.

  2. The use of low frequency HF beacons to derive layer shape

    International Nuclear Information System (INIS)

    The ATS-6 with its coherent multifrequency channels and various calibrations has brought the technology of beacon experiments to the point where the experimental accuracy exceeds that of some of the approximations used to derive total electron content. For example, the magnetic field term in the Faraday rotation experiment used to be given a mean value corresponding to about 50 km above the F layer peak. Another quantity that depends on profile shape is also available with present experiment, namely the refraction or second order term for carrier phase, modulation phase, or Faraday rotation. Some theoretical and experimental results are presented on these problems

  3. Core power distribution methodology in the BEACON PWR [pressurized water reactor] core monitoring system

    International Nuclear Information System (INIS)

    Westinghouse has developed an advanced operational core support package called BEACON which uses a fully analytical methodology for on-line prediction of 3-D [three-dimensional] power distributions. The system provides core monitoring, core measurement reduction, core analysis and follow, and core predictions. The heart of the system is a very fast and accurate three dimensional nodal code which is used for core simulation and predictions. The system uses a new methodology with the existing core instrumentation to infer the current measured power distribution. This methodology has been qualified and yields excellent results

  4. PNC and Hitachi results for stage 2 using the BEACON code

    International Nuclear Information System (INIS)

    The Co-ordinated Research Programme (CRP) on the Intercomparison of Core Mechanics Codes was agreed by the Consultants' Meeting of the IAEA International Working Group on Fast Reactor (IWGFR) in Vienna, 8-10 December 1987. This report presents the results for all the three problems set for Stage-2 in which the LMFBR Core Mechanics Codes should be validated using ex-reactor data on the basis of comparison of computational results. The example problems have been solved with the three dimensional structural analysis code for bowing history of fast breeder reactor cores, ''BEACON''. (author). 4 refs, figs and tabs

  5. Analysis and Enhancement of IEEE 802.15.4e DSME Beacon Scheduling Model

    OpenAIRE

    Kwang-il Hwang; Sung-wook Nam

    2014-01-01

    In order to construct a successful Internet of things (IoT), reliable network construction and maintenance in a sensor domain should be supported. However, IEEE 802.15.4, which is the most representative wireless standard for IoT, still has problems in constructing a large-scale sensor network, such as beacon collision. To overcome some problems in IEEE 802.15.4, the 15.4e task group proposed various different modes of operation. Particularly, the IEEE 802.15.4e deterministic and synchronous ...

  6. The Fifth Guiding Principle: Beacon, Banality, or Pandora's Box?

    Science.gov (United States)

    Morris, Michael

    2009-01-01

    Successfully providing guidance to others is no easy task. Such is the challenge faced by committees charged with developing guidelines for ethical professional practice. The process of establishing and revising the Program Evaluation Standards (Joint Committee, 1994), for example, is a multiyear task that must seems endless to participants: a…

  7. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe

    Directory of Open Access Journals (Sweden)

    Feng Zhang

    2015-06-01

    Full Text Available A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT, gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS microfluidic channels. DNA aptamer, or “artificial antibody”, was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the “aptamer beacon”, highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  8. Preliminary Statistics from the NASA Alphasat Beacon Receiver in Milan, Italy

    Science.gov (United States)

    Nessel, James; Zemba, Michael; Morse, Jacquelynne; Luini, Lorenzo; Riva, Carlo

    2015-01-01

    NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 gigahertz band. NASA GRC has developed and installed a K/Q-band (20/40 gigahertz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20/40 gigahertz signals broadcast from the Alphasat Aldo Paraboni TDP no. 5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we provide an overview of the design and data calibration procedure, and present 6 months of preliminary statistics of the NASA propagation terminal, which has been installed and operating in Milan since May 2014. The Q-band receiver has demonstrated a dynamic range of 40 decibels at an 8-hertz sampling rate. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models.

  9. Fluorescent Peptide Beacons for the Selective Ratiometric Detection of Heparin.

    Science.gov (United States)

    Maity, Debabrata; Schmuck, Carsten

    2016-09-01

    Heparin is extensively used as an anticoagulant drug during surgery. Two fluorophore-functionalized cationic oligopeptides HS 1 and HS 2 were developed to monitor heparin ratiometrically in aqueous media. Upon binding to heparin, HS 1 and HS 2 undergo a conformational change from an open form to a folded form, which leads to a distinct change in the fluorescence properties. HS 1 switches from pyrene monomer emission to an excimer emission. For HS 2, a fluorescence resonance energy transfer (FRET) process is enabled between a naphthalene donor and a dansyl acceptor. This method is highly selective for heparin relative to other similar biological analytes such as hyaluronic acid or chondroitin sulfate. HS 1 and HS 2 could also detect heparin ratiometrically in diluted bovine serum. The strong ratiometric emission color change can also be observed by the naked eye. Addition of the polycationic protein protamine releases both HS 1 and HS 2 from their heparin complex, which simultaneously restores pyrene monomer emission for the first case and decreases the FRET process for the latter case, respectively. Dynamic light scattering (DLS) and AFM studies confirm aggregate formation of heparin with HS 1 and HS 2. PMID:27534383

  10. A DNA tetrahedron-based molecular beacon for tumor-related mRNA detection in living cells.

    Science.gov (United States)

    Xie, Nuli; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Quan, Ke; Wang, He; Ying, Le; Ou, Min; Wang, Kemin

    2016-02-01

    Due to its low cytotoxicity, high resistance to enzymatic degradation, and cellular permeability, a DNA tetrahedron-based molecular beacon (DTMB) is designed for tumor-related TK1 mRNA detection in living cells, where the target sequence can induce the tetrahedron from contraction to extension, resulting in fluorescence restoration. PMID:26729323

  11. BEACON/MOD2A: a computer program for subcompartment analysis of nuclear reactor containment. A user's manual

    International Nuclear Information System (INIS)

    The BEACON code is a Best Estimate Advanced Containment code which being developed by EG and G, Idaho, Inc., at the Idaho National Engineering Laboratory. The program is designed to perform a best estimate analysis of the flow of a mixture of air, water, and steam in a nuclear reactor containment system under loss-of-coolant accident conditions. The code can simulate two-component, two-phase fluid flow in complex geometries using a combination of two-dimensional, one-dimensional, and lumped-parameter representations for the various parts of the system. The current version of BEACON, which is designated BEACON/MOD2A, contains mass and heat transfer models for wall film and for wall conduction. It is suitable for the evaluation of short term transients in PWR dry containment systems. This manual describes the models employed in BEACON/MOD2A and specifies code implementation requirements. It provides application information for input data preparation and for output data interpretation

  12. A molecular-beacon-based asymmetric PCR assay for easy visualization of amplicons in the diagnosis of trichomoniasis.

    Science.gov (United States)

    Sonkar, Subash C; Sachdev, Divya; Mishra, Prashant K; Kumar, Anita; Mittal, Pratima; Saluja, Daman

    2016-12-15

    The currently available nucleic acid amplification tests (NAATs) for trichomoniasis are accurate, quick and confirmative with superior sensitivity than traditional culture-based microbiology assays. However, these assays are associated with problems of carry over contamination, false positive results, requirement of technical expertise for performance and detection of end product. Hence, a diagnostic assay with easy visualization of the amplified product will be profitable. An in-house, rapid, sensitive, specific molecular-beacon-based PCR assay, using primers against pfoB gene of Trichomonas vaginalis, was developed and evaluated using dry ectocervical swabs (n=392) from symptomatic females with vaginal discharge. Total DNA was isolated and used as template for the PCR assays. The performance and reproducibility of PCR assay was evaluated by composite reference standard (CRS). For easy visualization of the amplified product, molecular-beacon was designed and amplicons were visualized directly using fluorescent handheld dark reader or by Micro-Plate Reader. Molecular-beacons are single-stranded hairpin shaped nucleic acid probes composed of a stem, with fluorophore/quencher pair and a loop region complementary to the desired DNA. The beacon-based PCR assay designed in the present study is highly specific as confirmed by competition experiments and extremely sensitive with detection limit of 20fg of genomic DNA (3-4 pathogens). The minimum infrastructure requirement and ease to perform the assay makes this method highly useful for resource poor countries for better disease management.

  13. REAL-TIME DETECTION OF SURVIVIN mRNA EXPRESSION IN CERVICAL CANCER CELL LINES USING MOLECULAR BEACON IMAGING

    Institute of Scientific and Technical Information of China (English)

    An Ruifang; He Dalin; Xue Yan; Wang Shu; Xie Li; Zhao Jun; Wang Xinyang; Yang Lili

    2006-01-01

    Objective To detect the expression of survivin mRNA in cervical cancer cell lines using molecular beacon imaging technology. Methods Human cervical cancer cells (HeLa and SiHa) and human fetal lung fibroblast HFL-I were cultured in vitro. After adding 100 nmol/L survivin mRNA molecular beacon, the fluorescent signals were observed under fluorescent microscope. The expressions of survivin in cervical cancer cells and HFL-I cell were examined by immunocytochemical streptravidin-biothin peroxidase (SP) assay at the same time. Results Two kinds of survivin mRNA molecular beacon, with different color fluorescence, had strong fluorescent signal in cervical cancer cell lines, and the signal in SiHa cell line was stronger, but these signals were not found in HFL-I ; Immunocytochemical staining of positive survivin was located in the cytoplasm of cervical cancer cell lines HeLa and SiHa, whereas, no expression of survivin was detected in HFL-I cell line. Conclusion The technology of molecular beacon imaging can be used to detect the expression of survivin mRNA in viable cells successfully, and may provide a new approach to the diagnosis of early stage cervical cancer and the following-up in the clinic.

  14. A quencher-free molecular beacon design based on pyrene excimer fluorescence using pyrene-labeled UNA (unlocked nucleic acid)

    DEFF Research Database (Denmark)

    Karlsen, Kasper Kannegård; Okholm, Anders Hauge; Kjems, Jørgen;

    2013-01-01

    A quencher-free molecular beacon capable of generating pyrene excimer fluorescence has been constructed using strategically positioned pyrene-UNA monomers. Hybridization of a fully complementary RNA target was accompanied by a pyrene excimer emission increase of more than 900%, and detection of RNA...

  15. Guiding Math Students to Campus Services: An Impact Evaluation of the Beacon Program at South Texas College

    Science.gov (United States)

    Visher, Mary; Butcher, Kristin F.; Cerna, Oscar S.

    2011-01-01

    This research rigorously evaluates whether a low-cost intervention can improve students' performance in developmental math. The "Beacon Mentoring Program" was developed at South Texas College by professors, administrators, and staff at the college. Surveys of students revealed that many did not have someone on campus whom they felt they could turn…

  16. A molecular-beacon-based asymmetric PCR assay for easy visualization of amplicons in the diagnosis of trichomoniasis.

    Science.gov (United States)

    Sonkar, Subash C; Sachdev, Divya; Mishra, Prashant K; Kumar, Anita; Mittal, Pratima; Saluja, Daman

    2016-12-15

    The currently available nucleic acid amplification tests (NAATs) for trichomoniasis are accurate, quick and confirmative with superior sensitivity than traditional culture-based microbiology assays. However, these assays are associated with problems of carry over contamination, false positive results, requirement of technical expertise for performance and detection of end product. Hence, a diagnostic assay with easy visualization of the amplified product will be profitable. An in-house, rapid, sensitive, specific molecular-beacon-based PCR assay, using primers against pfoB gene of Trichomonas vaginalis, was developed and evaluated using dry ectocervical swabs (n=392) from symptomatic females with vaginal discharge. Total DNA was isolated and used as template for the PCR assays. The performance and reproducibility of PCR assay was evaluated by composite reference standard (CRS). For easy visualization of the amplified product, molecular-beacon was designed and amplicons were visualized directly using fluorescent handheld dark reader or by Micro-Plate Reader. Molecular-beacons are single-stranded hairpin shaped nucleic acid probes composed of a stem, with fluorophore/quencher pair and a loop region complementary to the desired DNA. The beacon-based PCR assay designed in the present study is highly specific as confirmed by competition experiments and extremely sensitive with detection limit of 20fg of genomic DNA (3-4 pathogens). The minimum infrastructure requirement and ease to perform the assay makes this method highly useful for resource poor countries for better disease management. PMID:27318568

  17. To Light a Beacon: What Administrators Can Do To Make Schools Successful for All Students. ERIC/OSEP Topical Brief.

    Science.gov (United States)

    ERIC Clearinghouse on Disabilities and Gifted Education, Arlington, VA. ERIC/OSEP Special Project.

    In some schools, students with disabilities achieve exemplary results. To find out what these schools do that set them apart, the U.S. Office of Special Education Programs sponsored a series of studies focused on "Beacons of Excellence Schools." This topical brief highlights results from three of these studies. The University of Maryland study…

  18. A DNA tetrahedron-based molecular beacon for tumor-related mRNA detection in living cells.

    Science.gov (United States)

    Xie, Nuli; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Quan, Ke; Wang, He; Ying, Le; Ou, Min; Wang, Kemin

    2016-02-01

    Due to its low cytotoxicity, high resistance to enzymatic degradation, and cellular permeability, a DNA tetrahedron-based molecular beacon (DTMB) is designed for tumor-related TK1 mRNA detection in living cells, where the target sequence can induce the tetrahedron from contraction to extension, resulting in fluorescence restoration.

  19. Beacon of Hope? Lessons Learned from Efforts to Reduce Civilian Deaths from Police Shootings in an Australian State.

    Science.gov (United States)

    Saligari, Jessica; Evans, Richard

    2016-04-01

    In the 1990s, the police service in Victoria, Australia, faced a crisis of community confidence due to a spate of civilian deaths from police shootings. In that decade, twice as many civilians died at the hands of the police in Victoria than in every other Australian state combined. Most of those killed were mentally ill and affected by drugs and alcohol, and were rarely a serious threat except to themselves. The problem was also almost entirely an urban phenomenon. Shootings in rural communities, where mentally ill people were more likely to be personally known to local police, were (and remain) almost unknown. The large number of fatalities was recognised as a serious threat to public confidence, and Victoria Police introduced a ground-breaking training programme, Operation Beacon. Operating procedures and weapons training were fundamentally changed, to focus on de-escalation of conflict and avoiding or minimising police use of force. In the short term, Operation Beacon was successful. Shooting incidents were dramatically reduced. However, during the first decade of the new century, the number of civilians being killed again increased. This article examines Operation Beacon, both as a successful model for reducing civilian deaths at the hand of police and as a cautionary tale for police reform. We argue that the lessons of Operation Beacon have been gradually forgotten and that old habits and attitudes resurfaced. Fatal shootings of mentally ill civilians can be prevented, but if success is to be other than temporary, the Beacon philosophy must be continually reemphasised by police management. PMID:26666251

  20. Beacon of Hope? Lessons Learned from Efforts to Reduce Civilian Deaths from Police Shootings in an Australian State.

    Science.gov (United States)

    Saligari, Jessica; Evans, Richard

    2016-04-01

    In the 1990s, the police service in Victoria, Australia, faced a crisis of community confidence due to a spate of civilian deaths from police shootings. In that decade, twice as many civilians died at the hands of the police in Victoria than in every other Australian state combined. Most of those killed were mentally ill and affected by drugs and alcohol, and were rarely a serious threat except to themselves. The problem was also almost entirely an urban phenomenon. Shootings in rural communities, where mentally ill people were more likely to be personally known to local police, were (and remain) almost unknown. The large number of fatalities was recognised as a serious threat to public confidence, and Victoria Police introduced a ground-breaking training programme, Operation Beacon. Operating procedures and weapons training were fundamentally changed, to focus on de-escalation of conflict and avoiding or minimising police use of force. In the short term, Operation Beacon was successful. Shooting incidents were dramatically reduced. However, during the first decade of the new century, the number of civilians being killed again increased. This article examines Operation Beacon, both as a successful model for reducing civilian deaths at the hand of police and as a cautionary tale for police reform. We argue that the lessons of Operation Beacon have been gradually forgotten and that old habits and attitudes resurfaced. Fatal shootings of mentally ill civilians can be prevented, but if success is to be other than temporary, the Beacon philosophy must be continually reemphasised by police management.

  1. Use of a molecular beacon to track the activity of base excision repair protein OGG1 in live cells.

    Science.gov (United States)

    Mirbahai, Leda; Kershaw, Rachael M; Green, Richard M; Hayden, Rachel E; Meldrum, Rosalind A; Hodges, Nikolas J

    2010-02-01

    An abundant form of DNA damage caused by reactive oxygen species is 8-oxo-7,8-dihydroguanine for which the base excision repair protein 8-oxoguanine-DNA glycosylase 1 (OGG1) is a major repair enzyme. To assess the location and intracellular activity of the OGG1 protein in response to oxidative stress, we have utilised a fluorescence-quench molecular beacon switch containing a 8-oxo-dG:C base pair and a fluorescent and quencher molecule at opposite ends of a hairpin oligonucleotide. Oxidative stress was induced by treatment with potassium bromate. Flow cytometry demonstrated a concentration-dependent increase in the activity of OGG1 that was detected by the fluorescence produced when the oligonucleotide was cleaved in the cells treated with potassium bromate. This signal is highly specific and not detectable in OGG1 knock out cells. Induction of OGG1 activity is not a result of induction of OGG1 gene expression as assessed by qPCR suggesting a role for protein stabilisation or increased OGG1 catalytic activity. High resolution confocal microscopy pinpointed the location of the fluorescent molecular beacon in live cells to perinuclear regions that were identified as mitochondria by co-staining with mitotracker dye. There is no evidence of cut beacon within the nuclear compartment of the cell. Control experiments with a positive control beacon (G:C base pair and lacking the DAB quencher) did not result in mitochondrial localisation of fluorescence signal indicating that the dye does not accumulate in mitochondria independent of OGG1 activity. Furthermore, faint nuclear staining was apparent confirming that the beacon structure is able to enter the nucleus. In conclusion, these data indicate that the mitochondria are the major site for OGG1 repair activity under conditions of oxidative stress.

  2. Use of Molecular Beacon Probes for Real-Time PCR Detection of Plasmodium falciparum and Other Plasmodium Species in Peripheral Blood Specimens

    OpenAIRE

    Elsayed, Sameer; Plewes, Katherine; Church, Deirdre; Chow, Barbara; Zhang, Kunyan

    2006-01-01

    We describe the development and evaluation of a novel pair of real-time, fluorescence-based PCR assays using molecular beacon probes for rapid, sensitive, and specific detection and quantification of Plasmodium falciparum and other Plasmodium species organisms.

  3. Molecular beacon-based enzyme-free strategy for amplified DNA detection.

    Science.gov (United States)

    Huang, Jiahao; Wu, Jueqi; Li, Zhigang

    2016-05-15

    We report an enzyme-free, sensitive strategy for DNA detections through fluorescence amplification. The sensing method employs molecular beacons (MBs) and two single-stranded helper DNA probes. In the presence of a DNA target, it binds and opens an MB. This triggers the hybridizations between the MB and helper probes, and consequently releases the DNA target, which becomes available to react with another MB and enhances the fluorescence emission of the MBs. The detection limit of the proposed strategy is 0.58 pM, which is about 3 orders of magnitude better than the conventional MB-based method. This method is also fast and exhibits good selectivity. It is superior to previous MB-based amplification approaches employing enzymes or nanomaterials. PMID:26774091

  4. A simple molecular beacon with duplex-specific nuclease amplification for detection of microRNA.

    Science.gov (United States)

    Li, Yingcun; Zhang, Jiangyan; Zhao, Jingjing; Zhao, Likun; Cheng, Yongqiang; Li, Zhengping

    2016-02-01

    MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene activity, promoting or inhibiting cell proliferation, migration and apoptosis. Abnormal expression of miRNAs is associated with many diseases. Therefore, it is essential to establish a simple, rapid and sensitive miRNA detection method. In this paper, based on a simple molecular beacon (MB) and duplex-specific nuclease (DSN), we developed a target recycling amplification method for miRNA detection. By controlling the number of stem bases to 5, the MB probe used in this method can be prevented from hydrolysis by DSN without special modification. This assay is direct and simple to quantitatively detect miRNA with high sensitivity and specificity. The MB probe design provides a new strategy for nuclease-based amplification reaction. PMID:26688865

  5. Isothermal amplification detection of nucleic acids by a double-nicked beacon.

    Science.gov (United States)

    Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

    2016-03-01

    Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use. PMID:26706801

  6. Quantitative detection of ING1 mRNA under different gene regulation based on molecular beacon

    Institute of Scientific and Technical Information of China (English)

    LIU Bin; WANG Kemin; XIAO Zhiqiang; WANG Wei; TAN Weihong; SUN Yi; TANG Hongxing; YANG Xiaohai

    2006-01-01

    The effects of drug treatment, gene transfection, and p53 RNA interference (RNAi) on level of ING1 mRNA in tumor cells were quantitatively detected with the help of ING1 molecular beacon (MB)/cRNA standard curve based on MB detection technology. Results showed that the level of ING1 mRNA could be upregulated by 5-FU treatment or ING1 transfection in low expression cell line of MCF-7 and be inhibited by silencing p53 with RNAi technology in normal expression cell line of CNE2. The level of ING1 varied from 7.7×10-16 to 53.4×10-16 mol/ug total RNA of tumor cells. The results not only provided evidence for the regulation effects of gene expression but also were applied to investigating the interaction of multigenes on signal transduction pathway.

  7. ATS-6 radio beacon electron content measurements at Ootacamund, India, October 1975-July 1976

    International Nuclear Information System (INIS)

    An atlas of total slant-path columnar electron content data measured between the ATS-6 satellite and Ootacamund, India, a site near the magnetic Equator is presented. Although these measurements were taken during a solar minimum, the general level of flare and geomagnetic activity that occurred during the observation period is summarized. These total content (N(T)) data were derived from the modulation phase (group delay) of a carrier signal transmitted from the geostationary satellite's Radio Beacon Experiment. This atlas contains two data sets: (1) N(T) as 2-min subsamples digitally recorded between 2 October 1975 and 28 January 1976 corrected for ATS-6 pitch maneuvers and (2) N(T) as 15-min subsamples chart recorded between 21 October 1975 and 22 July 1976 but uncorrected for changes in satellite orientation

  8. Study of spread-F irregularities, a comparison with beacon satellite results

    International Nuclear Information System (INIS)

    Ground-based ionosonde data as well as phase and amplitude records from geostationary satellites ATS 6 and ETS II were taken at Gauhati. The ionospheric data were analysed for spread-F and its association with scintillations in radio beacon data has been examined through a period which covers a complete solar cycle. It is seen that this station does not show many characteristic features of low latitude stations. Post-midnight frequency spread is predominant. During geomagnetic storms dawn-time range spread is seen. The spread-F bears a positive correlation with Kp. Frequency spread is associated with amplitude scintillations, suggesting thereby that irregularity structures are thick. During disturbed conditions, range spread associated with scintillations and rapid build-up of morning-time integrated electron content have been observed. Here, an attempt has been made to offer an explanation in terms of precipitation of charged particles. (author)

  9. ATS6 radio beacon electron content measurements at Boulder, July 1974--May 1975

    International Nuclear Information System (INIS)

    Routine monitoring of the plasmaspheric content was a primary objective of the ATS6 Radio Beacon Experiment (RBE) and this set critical requirements on transmitter and receiver stabilities. The satellite transmitted linearly polarized signals on carrier frequencies of 40.016, 140.056, and 360.144 MHz, with modulations of 100.04 kHz and 1.004 MHz. This provided coarse and fine scales of measurements so that the cycle ambiguity in the phase measurements of both Faraday rotation and group delay could be resolved. This report summarizes 140 MHz data recorded at the Boulder, Colorado, ground station (40.13 degrees N, 105.24 degrees W) while ATS6 was positioned above 94 degrees west longitude, between July 1974 and May 1975. The satellite appeared at an azimuth of 163 degrees, elevation 42 degrees, with the projection of the ray path near the ground. All data were digitally recorded once per second

  10. Molecular beacon-based enzyme-free strategy for amplified DNA detection.

    Science.gov (United States)

    Huang, Jiahao; Wu, Jueqi; Li, Zhigang

    2016-05-15

    We report an enzyme-free, sensitive strategy for DNA detections through fluorescence amplification. The sensing method employs molecular beacons (MBs) and two single-stranded helper DNA probes. In the presence of a DNA target, it binds and opens an MB. This triggers the hybridizations between the MB and helper probes, and consequently releases the DNA target, which becomes available to react with another MB and enhances the fluorescence emission of the MBs. The detection limit of the proposed strategy is 0.58 pM, which is about 3 orders of magnitude better than the conventional MB-based method. This method is also fast and exhibits good selectivity. It is superior to previous MB-based amplification approaches employing enzymes or nanomaterials.

  11. Numerical simulation research on sodium laser beacon imagings through the atmosphere turbulence

    Science.gov (United States)

    Liu, Xiangyuan; Qian, Xianmei; Zhang, Suimeng; Zhao, Minfu; Cui, Chaolong; Huang, Honghua

    2016-01-01

    Based on the relative intensity distributions of Sodium Laser Beacon (SLB) and analysis of the on-axis imaging of incoherent light, considering the effects of atmospheric turbulence and the changes of telescope receiving diameter on the short-exposure SLB imagings on the focal plane, imagings of an extended source SLB are simulated under the three atmospheric turbulence models. Results indicate that sharpness and peak strehl ratio of SLB imagings increase but sharpness radius decrease with the decrease of atmosphere turbulence strengths. Moreover, the changes of telescope diameter from 3.0m to 1.5m cause the decrease of sharpness and peak strehl ratio but the increase of sharpness radius.

  12. Ground-water appraisal of the Fishkill-Beacon area, Dutchess County, New York

    Science.gov (United States)

    Snavely, Deborah S.

    1980-01-01

    The most productive aquifers in the Fishkill-Beacon area, Dutchess County, N.Y., are the sand and gravel beds in the northeast corner of the area and along the valleys of Fishkill and Clove Creeks. The average yield of these aquifers to wells is 190 gal/min (gallons per minute). The most productive bedrock aquifer is limestone, which yields an average of about 150 gal/min. Shale and granite each yield an average of less than 35 gal/min. About 4 billion gallons of available ground water is estimated to be in storage in the sand and gravel aquifers in the area. The area withdraws an average of 3.3 Mgal/d (million gallons per day) of water in June, July, and August and 2 Mgal/d during the remainder of the year. (USGS)

  13. Isothermal amplification detection of nucleic acids by a double-nicked beacon.

    Science.gov (United States)

    Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

    2016-03-01

    Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use.

  14. Angular anisoplanatism of a focused beam using beacons over horizontal path

    Science.gov (United States)

    Wu, Wu-ming; Ning, Yu

    2016-01-01

    The performance of the achieve laser beam propagation through atmospheric turbulence with adaptive optics is degraded by the fact that the wavefront aberrations difference. This error is only include the angular anisoplanatism when there is separation between the achieve laser beam and beacon. In the paper we derive an analytic expression for the effective angular anisoplanatism as a function of displacement angular when the turbulence profile is uniform. It shows that the effective angular anisoplanatism becomes weaker as the diameter of laser beams and the Fried transverse coherence length increase. We report results from field experiments that the effective angular anisoplanatism of a focused beam over horizontal path. It is found that measured and theoretical results are consistent. The effective wavefront variance increases with the strength of atmospheric turbulence and the angular displacement. And the constant phase of angular anisoplanatism has no effect on the Strehl ratio of the beam.

  15. A simple molecular beacon with duplex-specific nuclease amplification for detection of microRNA.

    Science.gov (United States)

    Li, Yingcun; Zhang, Jiangyan; Zhao, Jingjing; Zhao, Likun; Cheng, Yongqiang; Li, Zhengping

    2016-02-01

    MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene activity, promoting or inhibiting cell proliferation, migration and apoptosis. Abnormal expression of miRNAs is associated with many diseases. Therefore, it is essential to establish a simple, rapid and sensitive miRNA detection method. In this paper, based on a simple molecular beacon (MB) and duplex-specific nuclease (DSN), we developed a target recycling amplification method for miRNA detection. By controlling the number of stem bases to 5, the MB probe used in this method can be prevented from hydrolysis by DSN without special modification. This assay is direct and simple to quantitatively detect miRNA with high sensitivity and specificity. The MB probe design provides a new strategy for nuclease-based amplification reaction.

  16. Rapid Detection of the Epidermal Growth Factor Receptor Mutation in Non-Small-Cell Lung Cancer for Analysis of Acquired Resistance Using Molecular Beacons

    OpenAIRE

    Oh, Young-Hee; Kim, Youngwook; Kim, Young-Pil; Seo, Soo-Won; Mitsudomi, Tetsuya; Ahn, Myung-Ju; Park, Keunchil; Kim, Hak-Sung

    2010-01-01

    A secondary mutation (T790M) in epidermal growth factor receptor (EGFR) is a hallmark of acquired resistance to EGFR inhibitors used to treat non-small-cell lung cancer (NSCLC). Therefore, identifying the T790M mutation is crucial to guide treatment decisions. Given that DNA sequencing methods are time-consuming and insensitive, we developed and investigated the feasibility of using molecular beacons for the detection of the T790M mutation in EGFR. A molecular beacon complementary to the regi...

  17. Biomaterial constructs for delivery of multiple therapeutic genes: a spatiotemporal evaluation of efficacy using molecular beacons.

    Directory of Open Access Journals (Sweden)

    Jennifer C Alexander

    Full Text Available Gene therapy is emerging as a potential therapeutic approach for cardiovascular pathogenesis. An appropriate therapy may require multiple genes to enhance therapeutic outcome by modulating inflammatory response and angiogenesis in a controlled and time-dependent manner. Thus, the aim of this research was to assess the spatiotemporal efficacy of a dual-gene therapy model based on 3D collagen scaffolds loaded with the therapeutic genes interleukin 10 (IL-10, a potent anti-inflammatory cytokine, and endothelial nitric oxide synthase (eNOS, a promoter of angiogenesis. A collagen-based scaffold loaded with plasmid IL-10 polyplexes and plasmid eNOS polyplexes encapsulated into microspheres was used to transfect HUVECs and HMSCs cells.The therapeutic efficacy of the system was monitored at 2, 7 and 14 days for eNOS and IL-10 mRNA expression using RT-PCR and live cell imaging molecular beacon technology. The dual gene releasing collagen-based scaffold provided both sustained and delayed release of functional polyplexes in vitro over a 14 day period which was corroborated with variation in expression levels seen using RT-PCR and MB imaging. Maximum fold increases in IL-10 mRNA and eNOS mRNA expression levels occurred at day 7 in HMSCs and HUVECs. However, IL-10 mRNA expression levels seemed dependent on frequency of media changes and/or ease of transfection of the cell type. It was demonstrated that molecular beacons are able to monitor changes in mRNA levels at various time points, in the presence of a 3D scaffolding gene carrier system and the results complemented those of RT-PCR.

  18. Two wavelength-shifting molecular beacons for simultaneous and selective imaging of vesicular miRNA-21 and miRNA-31 in living cancer cells.

    Science.gov (United States)

    Bohländer, Peggy R; Abba, Mohammed L; Bestvater, Felix; Allgayer, Heike; Wagenknecht, Hans-Achim

    2016-06-14

    Two molecular beacons were designed as complementary fluorescent imaging probes for miRNA-21 and miRNA-31. Both beacons were prepared by a combination of solid-phase protocol and Cu(i)-catalyzed cycloaddition chemistry. The four photostable and bright fluorophores were attached to 2'-positions in the stem part of the two beacons. One beacon was labeled by a green-to-red emitting and the other by a blue-to-yellow emitting energy transfer pair. This two by two combination yields the four color emission readout. In vitro experiments demonstrate rapid and highly selective opening of both molecular beacons upon addition of the complementary target RNA and excellent green : red and blue : yellow emission color contrasts. Confocal microscopy of selected cancer cell lines provides evidence that a four color imaging of versicular miRNA-21 and miRNA-31 can be achieved both selectively and simultaneously upon transfection by the beacons, and that the fluorescent readouts track well with miRNA levels determined by PCR. PMID:27114268

  19. Real-time imaging of the epithelial-mesenchymal transition using microRNA-200a sequence-based molecular beacon-conjugated magnetic nanoparticles.

    Directory of Open Access Journals (Sweden)

    YoonSeok Choi

    Full Text Available The epithelial-mesenchymal transition (EMT plays important roles in tumor progression to metastasis. Thus, the development of an imaging probe that can monitor transient periods of the EMT process in live cells is required for a better understanding of metastatic process. Inspired by the fact that the mRNA expression levels of zinc finger E-box-binding homeobox 1 (ZEB1 increase when cells adopt mesenchyme characteristics and that microRNA-200a (miR-200a can bind to ZEB1 mRNA, we conjugated molecular beacon (MB mimicking mature miR-200a to magnetic nanoparticles (miR-200a-MB-MNPs and devised an imaging method to observe transitional changes in the cells during EMT. Transforming growth factor-β1 treated epithelial cells and breast cancer cell lines representing both epithelial and mesenchymal phenotypes were used for the validation of miR-200a-MB-MNPs as an EMT imaging probe. The real-time imaging of live cells acquired with the induction of EMT revealed an increase in fluorescence signals by miR-200a-MB-MNPs, cell morphology alterations, and the loss of cell-cell adhesion. Our results suggest that miR-200a-MB-MNPs can be used as an imaging probe for the real-time monitoring of the EMT process in live cells.

  20. Drift-parallax determination of the altitude of traveling ionospheric disturbances observed with the Los Alamos radio-beacon interferometer

    International Nuclear Information System (INIS)

    From 1993 to 1997, the Los Alamos very long baseline interferometer was routinely employed to detect traveling ionospheric disturbances (TID) and inner plasmaspheric irregularities by measuring the change in the electrical phase of several satellite beacon signals that backlit the inner plasmasphere and ionosphere from geosynchronous orbit. The fortuitous placement of two satellite beacons nearly in the Los Alamos geographic meridian, in late 1995, permits us to infer the nominal altitude of each TID event by employing a novel parallax ranging technique. In the context of this paper, the nominal altitude of a TID refers to the altitude at which the slant-path averaged, amplitude-weighted phase perturbation existed along the lines of sight from the interferometer to the satellite. In this paper, we outline the method and present validation results. copyright 1998 American Geophysical Union

  1. Use of molecular beacons for the rapid analysis of DNA damage induced by exposure to an atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    A rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is demonstrated. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma

  2. Design of a K/Q-Band Beacon Receiver for the Alphasat Technology Demonstration Payload (TDP) #5 Experiment

    Science.gov (United States)

    Morse, Jacquelynne R.

    2014-01-01

    This paper describes the design and performance of a coherent KQ-band (2040 GHz) beacon receiver developed at NASA Glenn Research Center (GRC) that will be installed at the Politecnico di Milano (POLIMI) for use in the Alphasat Technology Demonstration Payload 5 (TDP5) beacon experiment. The goal of this experiment is to characterize rain fade attenuation at 40 GHz to improve the performance of existing statistical rain attenuation models in the Q-band. The ground terminal developed by NASA GRC utilizes an FFT-based frequency estimation receiver capable of characterizing total path attenuation effects due to gaseous absorption, clouds, rain, and scintillation. The receiver system has been characterized in the lab and demonstrates a system dynamic range performance of better than 58 dB at 1 Hz and better than 48 dB at 10 Hz rates.

  3. Research on the acquisition and tracking simulation system of light beacon in satellite-ground optical communications

    Institute of Scientific and Technical Information of China (English)

    ZUO Tao; AI Yong; HUANG Hai-bo; SU Gui-bo

    2010-01-01

    @@ The study on the acquisition and tracking simulation system in satellite-ground optical communications is presented here.By applying global positioning system(GPS)coordinate calculation,the time needed in initial acquisition of light beacon can be reduced largely.Smith predictor is applied to compensate the mechanical hysteresis of tracking system and to improve the dynamic performance of the system.Tracking experiments over a i 6 km distance on the ground are conducted to verify the tracking of light beacon in satellite-ground optical communications.The standard deviation of horizontal coordinates is 35.3568 μrad and the maximum offset is 209.3675 μrad in stable tracking.

  4. Use of molecular beacons for the rapid analysis of DNA damage induced by exposure to an atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Hirofumi, E-mail: kurita@ens.tut.ac.jp, E-mail: mizuno@ens.tut.ac.jp; Miyachika, Saki; Yasuda, Hachiro; Takashima, Kazunori; Mizuno, Akira, E-mail: kurita@ens.tut.ac.jp, E-mail: mizuno@ens.tut.ac.jp [Department of Environmental and Life Sciences, Toyohashi University of Technology, Aichi 441-8580 (Japan)

    2015-12-28

    A rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is demonstrated. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma.

  5. Use of molecular beacons for the rapid analysis of DNA damage induced by exposure to an atmospheric pressure plasma jet

    Science.gov (United States)

    Kurita, Hirofumi; Miyachika, Saki; Yasuda, Hachiro; Takashima, Kazunori; Mizuno, Akira

    2015-12-01

    A rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is demonstrated. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma.

  6. Simple, rapid detection of influenza A (H1N1) viruses using a highly sensitive peptide-based molecular beacon.

    Science.gov (United States)

    Lim, Eun-Kyung; Guk, Kyeonghye; Kim, Hyeran; Chung, Bong-Hyun; Jung, Juyeon

    2016-01-01

    A peptide-based molecular beacon (PEP-MB) was prepared for the simple, rapid, and specific detection of H1N1 viruses using a fluorescence resonance energy transfer (FRET) system. The PEP-MB exhibited minimal fluorescence in its "closed" hairpin structure. However, in the presence of H1N1 viruses, the specific recognition of the hemagglutinin (HA) protein of H1 strains by the PEP-MB causes the beacon to assume an "open" structure that emits strong fluorescence. The PEP-MB could detect H1N1 viruses within 15 min or even 5 min and can exhibit strong fluorescence even at low viral concentrations, with a detection limit of 4 copies.

  7. Simple, rapid detection of influenza A (H1N1) viruses using a highly sensitive peptide-based molecular beacon.

    Science.gov (United States)

    Lim, Eun-Kyung; Guk, Kyeonghye; Kim, Hyeran; Chung, Bong-Hyun; Jung, Juyeon

    2016-01-01

    A peptide-based molecular beacon (PEP-MB) was prepared for the simple, rapid, and specific detection of H1N1 viruses using a fluorescence resonance energy transfer (FRET) system. The PEP-MB exhibited minimal fluorescence in its "closed" hairpin structure. However, in the presence of H1N1 viruses, the specific recognition of the hemagglutinin (HA) protein of H1 strains by the PEP-MB causes the beacon to assume an "open" structure that emits strong fluorescence. The PEP-MB could detect H1N1 viruses within 15 min or even 5 min and can exhibit strong fluorescence even at low viral concentrations, with a detection limit of 4 copies. PMID:26509476

  8. How a Beacon Community Program in New Orleans Helped Create a Better Health Care System By Building Relationships Before Technology

    OpenAIRE

    Khurshid, Anjum; Brown, Lisanne

    2014-01-01

    Introduction: In the aftermath of Hurricane Katrina, much of New Orleans’ healthcare infrastructure was destroyed. Initial federal funding after the storm expanded primary care services and helped set up medical homes for New Orleans’ large uninsured and underinsured population. Following that, the Beacon Community in New Orleans, charged with improving health care through the use of technology, decided the best way to accomplish those goals was to build community partnerships and introduce t...

  9. Multicolour hybrid nanoprobes of molecular beacon conjugated quantum dots: FRET and gel electrophoresis assisted target DNA detection

    International Nuclear Information System (INIS)

    We have developed multicolour hybrid DNA probes employing green, yellow and orange colour quantum dot conjugated molecular beacons with black hole quencher 2. Optical and electrophoretic characterization revealed fluorescent energy transfer that follows the FRET mechanism with single nucleotide discrimination. Target DNA identification was observed to be highly sensitive up to 8 ng in gel electrophoresis. Comparison with the conventional organic dye SYBR Gold(TM) showed that our hybrid nanoprobes exhibit more stable performance with less background signal

  10. Exciton interaction in molecular beacons: a sensitive sensor for short range modifications of the nucleic acid structure

    OpenAIRE

    Bernacchi, Serena; Mély, Yves

    2001-01-01

    Molecular beacons are hairpin-shaped, single-stranded oligonucleotides constituting sensitive fluorescent DNA probes widely used to report the presence of specific nucleic acids. In its closed form the stem of the hairpin holds the fluorophore covalently attached to one end, close to the quencher, which is covalently attached to the other end. Here we report that in the closed form the fluorophore and the quencher form a ground state intramolecular heterodimer whos...

  11. A FRET-enabled molecular peptide beacon with a significant red shift for the ratiometric detection of nucleic acids.

    Science.gov (United States)

    Maity, Debabrata; Jiang, Juanjuan; Ehlers, Martin; Wu, Junchen; Schmuck, Carsten

    2016-05-01

    A cationic molecular peptide beacon NAP1 functionalized with a fluorescence resonance energy transfer-pair at its ends allows the ratiometric detection of ds-DNA with a preference for AT rich sequences. NAP1 most likely binds in a folded form into the minor groove of ds-DNA, which results in a remarkable change in its fluorescence properties. As NAP1 exhibits quite low cytotoxicity, it can also be used for imaging of nuclear DNA in cells. PMID:27071707

  12. A FRET-enabled molecular peptide beacon with a significant red shift for the ratiometric detection of nucleic acids.

    Science.gov (United States)

    Maity, Debabrata; Jiang, Juanjuan; Ehlers, Martin; Wu, Junchen; Schmuck, Carsten

    2016-05-01

    A cationic molecular peptide beacon NAP1 functionalized with a fluorescence resonance energy transfer-pair at its ends allows the ratiometric detection of ds-DNA with a preference for AT rich sequences. NAP1 most likely binds in a folded form into the minor groove of ds-DNA, which results in a remarkable change in its fluorescence properties. As NAP1 exhibits quite low cytotoxicity, it can also be used for imaging of nuclear DNA in cells.

  13. Molecular beacon probes–base multiplex NASBA Real-time for detection of HIV-1 and HCV

    Directory of Open Access Journals (Sweden)

    Samira Mohammadi Yeganeh

    2012-06-01

    Full Text Available Background and Objectives: Developed in 1991, nucleic acid sequence-based amplification (NASBA has been introduced as a rapid molecular diagnostic technique, where it has been shown to give quicker results than PCR, and it can also be more sensitive. This paper describes the development of a molecular beacon-based multiplex NASBA assay for simultaneous detection of HIV-1 and HCV in plasma samples.Materials and Methods: A well-conserved region in the HIV-1 pol gene and 5’-NCR of HCV genome were used for primers and molecular beacon design. The performance features of HCV/HIV-1 multiplex NASBA assay including analytical sensitivity and specificity, clinical sensitivity and clinical specificity were evaluated.Results: The analysis of scalar concentrations of the samples indicated that the limit of quantification of the assay was < 1000 copies/ml for HIV-1 and < 500copies/ml for HCV with 95% confidence interval. Multiplex NASBA assay showed a 98% sensitivity and 100% specificity. The analytical specificity study with BLAST software demonstrated that the primers do not attach to any other sequences except for that of HIV-1 or HCV. The primers and molecular beacon probes detected all HCV genotypes and all major variants of HIV-1.Conclusion: This method may represent a relatively inexpensive isothermal method for detection of HIV-1/HCV co-infection in monitoring of patients.

  14. DNA-templated silver nanoclusters based label-free fluorescent molecular beacon for the detection of adenosine deaminase.

    Science.gov (United States)

    Zhang, Kai; Wang, Ke; Xie, Minhao; Zhu, Xue; Xu, Lan; Yang, Runlin; Huang, Biao; Zhu, Xiaoli

    2014-02-15

    A general and reliable fluorescent molecular beacon is proposed in this work utilizing DNA-templated silver nanoclusters (AgNCs). The fluorescent molecular beacon has been employed for sensitive determination of the concentration of adenosine deaminase (ADA) and its inhibition. A well-designed oligonucleotide containing three functional regions (an aptamer region for adenosine assembly, a sequence complementary to the region of the adenosine aptamer, and an inserted six bases cytosine-loop) is adopted as the core element in the strategy. The enzymatic reaction of adenosine catalyzed by ADA plays a key role as well in the regulation of the synthesis of the DNA-templated AgNCs, i.e. the signal indicator. The intensity of the fluorescence signal may thereby determine the concentration of the enzyme and its inhibitor. The detection limit of the ADA can be lowered to 0.05 UL(-1). Also, 100 fM of a known inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine hydrochloride (EHNA) is enough to present distinguishable fluorescence emission. Moreover, since the fluorescent signal indicator is not required to be bound with the oligonucleotide, this fluorescent molecular beacon may integrate the advantages of both the label-free and signal-on strategies.

  15. Examining the validity of using a Gaussian Schell Model for modeling an extended beacon on a rough perfectly reflecting surface

    Science.gov (United States)

    Basu, Santasri; Hyde, Milo W.; McCrae, Jack E.; Spencer, Mark F.; Fiorino, Steven T.

    2014-10-01

    In military applications that use adaptive optics, an extended beacon instead of a point source beacon is created at the target due to atmospheric turbulence and other factors. These beacons, which have a finite spatial extent and exhibit varying degrees of coherence, are typically modeled in existing literature as a Gaussian Schell Model (GSM) due to its analytical tractability. Earlier, we used a full wave computational technique to evaluate the scattered field from a rough impedance surface in vacuum. The results showed some deviations from GSM behavior. The present work uses a simulation approach based on Physical Optics (PO) approximation to study the scattering behavior in presence of atmospheric turbulence. A fully coherent Gaussian beam is propagated through atmospheric phase screens to the rough surface target plane. The PO current is computed on the rough surface and the scattered field right above the surface is determined. The scattered light is propagated through a second set of atmospheric phase screens and thus the double passage through the atmosphere is realized. The rough surface is simulated using statistical parameters derived from profilometer measurements of standard targets. Through multiple realizations of the atmosphere and the rough surface, the statistics of the scattered field is determined. The simulations are done with different strengths of turbulence and different roughness scales of the target. The results are compared with a GSM. An effects model where the rough surface is modeled as a phase screen has also been implemented in order to verify the nature of the speckle returns.

  16. A quantum dot-aptamer beacon using a DNA intercalating dye as the FRET reporter: application to label-free thrombin detection.

    Science.gov (United States)

    Chi, Chun-Wei; Lao, Yeh-Hsing; Li, Yi-Shan; Chen, Lin-Chi

    2011-03-15

    A new quantum dot (QD)-aptamer (apt) beacon that acts by folding-induced dissociation of a DNA intercalating dye, BOBO-3(B), is demonstrated with label-free thrombin detection. The beacon, denoted as QD-apt:B, is constructed by (1) coupling of a single-stranded thrombin aptamer to Qdot 565 via EDC/Sulfo-NHS chemistry and (2) staining the duplex regions of the aptamer on QD with excess BOBO-3 before thrombin binding. When mixing a thrombin sample with QD-apt:B, BOBO-3 is competed away from the beacon due to target-induced aptamer folding, which then causes a decrease in QD fluorescence resonance energy transfer (FRET)-mediated BOBO-3 emission and achieves thrombin quantitation. In this work, the effects of Mg(2+), coupling time, and aptamer type on the beacon's performances are investigated and discussed thoroughly with various methods, including transmission electron microscopy (TEM), dynamic light scattering (DLS), and two-color differential gel electrophoresis. Using the best aptamer beacon (HTQ37), we attain highly specific and wide-range detection (from nM to μM) of thrombin in buffer, and the beacon can sense nM-range thrombin in 15% diluted serum. Compared to the reported QD aptamer assays, our method is advantageous from the aspect of using a simple sensory unit design without losing the detection sensitivity. Therefore, we consider the QD-apt:B beacon a potential alternative to immuno-reagents and an effective tool to study nucleic acid folding on QD as well. PMID:21306887

  17. Appoach to realizing weak hydroacoustic beaconing signal based on DSP%一种基于DSP的声信标弱信号提取方法

    Institute of Scientific and Technical Information of China (English)

    李笑媛; 程晶; 那健

    2014-01-01

    This paper introduces a method to realize weak hydroacoustic beaconing signal detecting base on DSP. According to the capability parameters of the hydroacoustic beaconing that the subject have adopted and the application of the hydroacoustic beaconing to the specific environment, also because the matching filter is the best filter means in the condition of additive white noise, it can make the SNR of the output signal to maximize, so this paper adopted the matching filter method, and at last the subject realized weak hydroacoustic beaconing signal detecting on DSP module. After real testing, the system which is good for weak hydroacoustic beaconing signal detecting can run real-time and realize easily. After sea trials, the system using the method can quickly find the target when hydroacoustic beaconing in a long distance. The sea trials shows the method can improve detection distance and easy to use in the areas of the weak hydroacoustic beaconing signal detecting.%介绍一种基于DSP处理模块实现声信标弱信号提取的方法。针对声信标的性能参数及其具体应用环境,采用一种在加性白噪声环境下能够使信号的输出信噪比达到最大的匹配滤波方法,并将其在DSP处理模块上实现,最终将检测结果以音频和视频的形式输出。经过实际应用测试,该方法易于实现,实时性好,在复杂的海洋背景噪声下可以较好提高声信标的作用距离。

  18. A quantum dot-aptamer beacon using a DNA intercalating dye as the FRET reporter: application to label-free thrombin detection.

    Science.gov (United States)

    Chi, Chun-Wei; Lao, Yeh-Hsing; Li, Yi-Shan; Chen, Lin-Chi

    2011-03-15

    A new quantum dot (QD)-aptamer (apt) beacon that acts by folding-induced dissociation of a DNA intercalating dye, BOBO-3(B), is demonstrated with label-free thrombin detection. The beacon, denoted as QD-apt:B, is constructed by (1) coupling of a single-stranded thrombin aptamer to Qdot 565 via EDC/Sulfo-NHS chemistry and (2) staining the duplex regions of the aptamer on QD with excess BOBO-3 before thrombin binding. When mixing a thrombin sample with QD-apt:B, BOBO-3 is competed away from the beacon due to target-induced aptamer folding, which then causes a decrease in QD fluorescence resonance energy transfer (FRET)-mediated BOBO-3 emission and achieves thrombin quantitation. In this work, the effects of Mg(2+), coupling time, and aptamer type on the beacon's performances are investigated and discussed thoroughly with various methods, including transmission electron microscopy (TEM), dynamic light scattering (DLS), and two-color differential gel electrophoresis. Using the best aptamer beacon (HTQ37), we attain highly specific and wide-range detection (from nM to μM) of thrombin in buffer, and the beacon can sense nM-range thrombin in 15% diluted serum. Compared to the reported QD aptamer assays, our method is advantageous from the aspect of using a simple sensory unit design without losing the detection sensitivity. Therefore, we consider the QD-apt:B beacon a potential alternative to immuno-reagents and an effective tool to study nucleic acid folding on QD as well.

  19. Appoach to realizing weak hydroacoustic beaconing signal based on DSP%一种基于DSP的声信标弱信号提取方法

    Institute of Scientific and Technical Information of China (English)

    李笑媛; 程晶; 那健

    2014-01-01

    介绍一种基于DSP处理模块实现声信标弱信号提取的方法。针对声信标的性能参数及其具体应用环境,采用一种在加性白噪声环境下能够使信号的输出信噪比达到最大的匹配滤波方法,并将其在DSP处理模块上实现,最终将检测结果以音频和视频的形式输出。经过实际应用测试,该方法易于实现,实时性好,在复杂的海洋背景噪声下可以较好提高声信标的作用距离。%This paper introduces a method to realize weak hydroacoustic beaconing signal detecting base on DSP. According to the capability parameters of the hydroacoustic beaconing that the subject have adopted and the application of the hydroacoustic beaconing to the specific environment, also because the matching filter is the best filter means in the condition of additive white noise, it can make the SNR of the output signal to maximize, so this paper adopted the matching filter method, and at last the subject realized weak hydroacoustic beaconing signal detecting on DSP module. After real testing, the system which is good for weak hydroacoustic beaconing signal detecting can run real-time and realize easily. After sea trials, the system using the method can quickly find the target when hydroacoustic beaconing in a long distance. The sea trials shows the method can improve detection distance and easy to use in the areas of the weak hydroacoustic beaconing signal detecting.

  20. Beacon-like/ubiquitin-5-like immunoreactivity is highly expressed in human hypothalamus and increased in haloperidol-treated schizophrenics and a rat model of schizophrenia.

    Science.gov (United States)

    Bernstein, Hans-Gert; Lendeckel, Uwe; Dobrowolny, Henrik; Stauch, Renate; Steiner, Johann; Grecksch, Gisela; Becker, Axel; Jirikowski, Gustav F; Bogerts, Bernhard

    2008-04-01

    The beacon gene is involved in the regulation of energy metabolism, food intake, and obesity. We localized its gene product, beacon-/ubiquitin 5-like immunoreactivity in brains of normal-weight, non-psychotic individuals, adipose (BMI over 32), non-psychotic individuals, and haloperidol-treated schizophrenics. The protein was found to be highly expressed in many neurons of the paraventricular and supraoptic hypothalamic nuclei. Besides, it was detected in neurons of other hypothalamic areas (suprachiasmatic, arcuate, and ventromedial nuclei) as well as outside the hypothalamus (Nuc. basalis Meynert, thalamus, hippocampus, and some neocortical areas). A morphometric analysis of beacon-immunoreactive hypothalamic and neocortical neurons revealed that compared to normal-weight controls in haloperidol-treated schizophrenics, there was a significant increase of protein-expressing supraoptic, paraventricular, and orbitofrontal neurons. However, a significant increase in beacon-expressing supraoptic neurons was also seen in adipose, non-psychotic individuals in comparison with normal-weight controls. Haloperidol at different doses has no effect on beacon expression in SHSY5Y neuroblastoma cells, which makes the assumption unlikely that haloperidol per se is responsible for the increased neuronal expression of the peptide in schizophrenics. In rats with a neonatal lesion of the ventral hippocampus (a widely used animal model of schizophrenia), we found an increased neuronal expression of beacon in the paraventricular and supraoptic nuclei. We suppose that elevated hypothalamic expression of beacon-like protein in non-obese schizophrenics is not primarily related to metabolic alterations, but to a certain role in schizophrenia, which is possibly unrelated to aspects of weight gain and obesity. The latter assumption finds some support by data obtained in rats with ventral hippocampus lesion.

  1. A Research of Children Amusement Project Design Based on Beacon Technology%基于Beacon技术的儿童游乐项目设计研究

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Experience economy gradually becomes the characteristic of the time, such as the representative theme park, and amusement park which contain a huge development market. In view of the issues within domestic children amusement parks, the lack of effective design and planning, or undesirable service quality, the paper aims to provide some new ideas and approach to design it better. It starts from the Beacon technology and the big data processing technology. Speciifcally, with the big data accumulated by Beacon location aware technology, the theories based on experience will be built, thus with the analysis of the need of children and their feeling, an activity data can be collected. With the analyzed result, it is able to provide approaches to construct higher level children amusement parks. Finally, with a certain theory and practical evidence, the new ideas and ways for designing and building the amusement project can be carried out.%体验经济正逐步成为时代的特征,作为体验经济代表的主题公园、游乐场等有着巨大的市场发展空间。针对国内儿童游乐项目缺乏有效的设计及规划,及其服务质量并不能满足儿童消费者的需求等问题,主要运用Beacon技术及大数据处理技术,为儿童游乐项目设计提供一些新的思路和方法。即以Beacon位置感知技术为基础形成大数据,通过大数据技术结合体验设计理论,分析儿童对游乐项目的需求、体验感受、活动数据等,为建立高水平的儿童游乐项目设计提供相应的路径,最终为儿童游乐项目设计实施新的思路和方法,提供一定的理论与实践依据。

  2. 基于Beacon技术的儿童游乐项目设计研究%A Research of Children Amusement Project Design Based on Beacon Technology

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Experience economy gradually becomes the characteristic of the time, such as the representative theme park, and amusement park which contain a huge development market. In view of the issues within domestic children amusement parks, the lack of effective design and planning, or undesirable service quality, the paper aims to provide some new ideas and approach to design it better. It starts from the Beacon technology and the big data processing technology. Speciifcally, with the big data accumulated by Beacon location aware technology, the theories based on experience will be built, thus with the analysis of the need of children and their feeling, an activity data can be collected. With the analyzed result, it is able to provide approaches to construct higher level children amusement parks. Finally, with a certain theory and practical evidence, the new ideas and ways for designing and building the amusement project can be carried out.%体验经济正逐步成为时代的特征,作为体验经济代表的主题公园、游乐场等有着巨大的市场发展空间。针对国内儿童游乐项目缺乏有效的设计及规划,及其服务质量并不能满足儿童消费者的需求等问题,主要运用Beacon技术及大数据处理技术,为儿童游乐项目设计提供一些新的思路和方法。即以Beacon位置感知技术为基础形成大数据,通过大数据技术结合体验设计理论,分析儿童对游乐项目的需求、体验感受、活动数据等,为建立高水平的儿童游乐项目设计提供相应的路径,最终为儿童游乐项目设计实施新的思路和方法,提供一定的理论与实践依据。

  3. A SHORT INTERFERING RNA MOLECULAR BEACON FOR THE ATTENUATION OF MYCOBACTERIAL INFECTION

    Directory of Open Access Journals (Sweden)

    Remo George

    2014-01-01

    Full Text Available The ability of the pathogen Mycobacterium Tuberculosis (MTB to invade and survive within macrophages of granulomas is attributed to the product of the Mammalian Cell Entry (MCE operon whose gene, mce4A, encodes a cholesterol transporter that transports host lipids into the bacterium that allows the bacterium to survive during chronic infection. Here, we proposed and tested the hypothesis that a mce4A siRNA molecular beacon can be used to attenuate mycobacterial infection in macrophages. Mce4A gene was cloned and expressed in E. coli (E. coli-4A and differentiated U937 cells were transduced with piLenti-siRNA-GFP phage expressing the mce4A siRNA for 24 h. This was followed by infection with either E. coli-4A or M. smegmatis for 3 h followed by incubation for 0, 3, 6, 24 and 48 h. The cells were lysed and the lysates were plated on LB agar plates containing ampicillin (100 µg mL-1 or on 7H11 media and incubated at 37°C overnight. Our results showed that the siRNA treatment attenuated E.coli-4A infection in macrophages at 3, 6, 24 and 48 h by 0, 77, 59.6 and 99.7%, respectively. Our results also showed that the siRNA treatment attenuated M. smegmatis infection in macrophages at 3, 6, 24 and 48 h. by 94.8, 70.3, 98.9 and 93.4%, respectively. In conclusion, a mce4A siRNA molecular beacon was successfully delivered and stably expressed in macrophages which attenuated E. coli expressing mce4A (E. coli-4A and M. smegmatis infection in macrophages.

  4. Turbulence-induced low order aberrations of optical wavefronts in partial adaptive compensation with Rayleigh beacon or sodium beacon%激光导引星自适应光学系统对大气湍流低阶像差校正效果分析

    Institute of Scientific and Technical Information of China (English)

    万敏; 苏毅; 向汝建

    2001-01-01

    The residual phase error after correction for turbulence-induced phase aberrations by a partially compensating adaptive optics system (with temporal lag and limited space resolution) is computed by using the phase expansion on the Zernike polynomials in this paper. The computation can be used to derive the maximum order of aberration to be corrected to get the most from the compensation. The partially compensating adaptive optics system with Rayleigh beacon or sodium beacon as reference is computed also in this paper. The results show, the system with sodium beacon requires higher space frequency than the system with Rayleigh beacon. And the off-axis anisoplanatism effect due to the angular separation between the object and the beacon or the system temporal lag is more serious for the system with sodium beacon. The correction for high order aberration is more suitable for the system with sodium beacon than the system with Rayleigh beacon.%在对大气湍流相位扰动进行Zernike多项式展开的基础上,通过对信标和目标光的Zernike系数相关因子的推导,得到了实际自适应光学系统(系统存在时间滞后和有限的空间分辨率)对相位扰动各阶像差的校正残差公式。同时结合实际,对瑞利导星以及钠导星自适应光学系统补偿大气湍流各阶像差的能力进行了计算和分析,为实际自适应光学系统的设计提供了理论参考。

  5. Trifunctional molecular beacon-mediated quadratic amplification for highly sensitive and rapid detection of mercury(II) ion with tunable dynamic range.

    Science.gov (United States)

    Zhao, Yue; Liu, Huaqing; Chen, Feng; Bai, Min; Zhao, Junwu; Zhao, Yongxi

    2016-12-15

    Analyses of target with low abundance or concentration varying over many orders of magnitude are severe challenges faced by numerous assay methods due to their modest sensitivity and limited dynamic range. Here, we introduce a homogeneous and rapid quadratic polynomial amplification strategy through rational design of a trifunctional molecular beacon, which serves as not only a reporter molecule but also a bridge to couple two stage amplification modules without adding any reaction components or process other than basic linear amplification. As a test bed for our studies, we took mercury(II) ion as an example and obtained a high sensitivity with detection limit down to 200 pM within 30min. In order to create a tunable dynamic range, homotropic allostery is employed to modulate the target specific binding. When the number of metal binding site varies from 1 to 3, signal response is programmed accordingly with useful dynamic range spanning 50, 25 and 10 folds, respectively. Furthermore, the applicability of the proposed method in river water and biological samples are successfully verified with good recovery and reproducibility, indicating considerable potential for its practicality in complex real samples.

  6. Trifunctional molecular beacon-mediated quadratic amplification for highly sensitive and rapid detection of mercury(II) ion with tunable dynamic range.

    Science.gov (United States)

    Zhao, Yue; Liu, Huaqing; Chen, Feng; Bai, Min; Zhao, Junwu; Zhao, Yongxi

    2016-12-15

    Analyses of target with low abundance or concentration varying over many orders of magnitude are severe challenges faced by numerous assay methods due to their modest sensitivity and limited dynamic range. Here, we introduce a homogeneous and rapid quadratic polynomial amplification strategy through rational design of a trifunctional molecular beacon, which serves as not only a reporter molecule but also a bridge to couple two stage amplification modules without adding any reaction components or process other than basic linear amplification. As a test bed for our studies, we took mercury(II) ion as an example and obtained a high sensitivity with detection limit down to 200 pM within 30min. In order to create a tunable dynamic range, homotropic allostery is employed to modulate the target specific binding. When the number of metal binding site varies from 1 to 3, signal response is programmed accordingly with useful dynamic range spanning 50, 25 and 10 folds, respectively. Furthermore, the applicability of the proposed method in river water and biological samples are successfully verified with good recovery and reproducibility, indicating considerable potential for its practicality in complex real samples. PMID:27497195

  7. A novel enzyme-linked immunosorbent assay for detection of Escherichia coli O157:H7 using immunomagnetic and beacon gold nanoparticles.

    Science.gov (United States)

    Shen, Zhiqiang; Hou, Nannan; Jin, Min; Qiu, Zhigang; Wang, Jingfeng; Zhang, Bin; Wang, Xinwei; Wang, Jie; Zhou, Dongsheng; Li, Junwen

    2014-01-01

    This paper presents a functional nanoparticle-enhanced enzyme-linked immunosorbent assay (FNP-ELISA) for detection of enterohemorrhagic Escherichia coli (EHEC) O157:H7. Immunomagnetic nanoparticles (IMMPs) conjugated with monoclonal anti-O157:H7 antibody were used to capture E. coli O157:H7. Beacon gold nanoparticles (B-GNPs) coated with polyclonal anti-O157:H7 and biotin single-stranded DNA (B-DNA) were then subjective to immunoreaction with E. coli O157:H7, which was followed by streptavidin-horseradish peroxidase (Strep-HRP) conjugated with B-GNPs based on a biotin-avidin system. The solutions containing E. coli O157:H7, IMMPs, B-GNPs, and Strep-HRP were collected for detecting color change. The signal was significantly amplified with detection limits of 68 CFU mL(-1) in PBS and 6.8 × 10(2) to 6.8 × 10(3) CFU mL(-1) in the food samples. The FNP-ELISA method developed in this study was two orders of magnitude more sensitive than immunomagnetic separation ELISA (IMS-ELISA) and four orders of magnitude more sensitive than C-ELISA. The entire detection process of E. coli O157:H7 lasted only 3 h, and thus FNP-ELISA is considered as a time-saving method.

  8. A molecular beacon microarray based on a quantum dot label for detecting single nucleotide polymorphisms.

    Science.gov (United States)

    Guo, Qingsheng; Bai, Zhixiong; Liu, Yuqian; Sun, Qingjiang

    2016-03-15

    In this work, we report the application of streptavidin-coated quantum dot (strAV-QD) in molecular beacon (MB) microarray assays by using the strAV-QD to label the immobilized MB, avoiding target labeling and meanwhile obviating the use of amplification. The MBs are stem-loop structured oligodeoxynucleotides, modified with a thiol and a biotin at two terminals of the stem. With the strAV-QD labeling an "opened" MB rather than a "closed" MB via streptavidin-biotin reaction, a sensitive and specific detection of label-free target DNA sequence is demonstrated by the MB microarray, with a signal-to-background ratio of 8. The immobilized MBs can be perfectly regenerated, allowing the reuse of the microarray. The MB microarray also is able to detect single nucleotide polymorphisms, exhibiting genotype-dependent fluorescence signals. It is demonstrated that the MB microarray can perform as a 4-to-2 encoder, compressing the genotype information into two outputs. PMID:26397421

  9. Determining the Solar Inactivation Rate of BK Polyomavirus by Molecular Beacon.

    Science.gov (United States)

    Reano, Dane C; Yates, Marylynn V

    2016-07-01

    The application of molecular beacons (MB) that bind to precise sequences of mRNA provides a near-universal approach in detecting evidence of viral replication. Here, we demonstrate the detection of BK Polyomavirus (BKPyV), an emerging indicator of microbiological water quality, by a quantum dot-based MB. The MB allowed us to rapidly characterize the inactivation rate of BKPyV following exposure to a solar simulator (kobs = 0.578 ± 0.024 h(-1), R(2) = 0.92). Results were validated through a traditional cell-culture assay with immunofluorescence detection (kobs = 0.568 ± 0.011 h(-1), R(2) = 0.97), which exhibited a strong correlation to MB data (R(2) = 0.93). Obtaining solar inactivation rates for BKPyV demonstrates the first use of a MB in characterizing a microbiological inactivation profile and helps assess the appropriateness of adopting BKPyV as an indicator organism for water quality. PMID:27269231

  10. Cincinnati Beacon Community Program highlights challenges and opportunities on the path to care transformation.

    Science.gov (United States)

    Fairbrother, Gerry; Trudnak, Tara; Christopher, Ronda; Mansour, Mona; Mandel, Keith

    2014-05-01

    The Cincinnati, Ohio, metropolitan area was one of seventeen US communities to participate in the federal Beacon Community Cooperative Agreement Program to demonstrate how health information technology (IT) could be used to improve health care. Given $13.7 million to spend in thirty-one months, the Cincinnati project involved hundreds of physicians, eighty-seven primary care practices, eighteen major hospital partners, and seven federally qualified health centers and community health centers. The thrust of the program was to build a shared health IT infrastructure to support quality improvement through data exchange, registries, and alerts that notified primary care practices when a patient visited an emergency department or was admitted to a hospital. A special focus of this program was on applying these tools to adult patients with diabetes and pediatric patients with asthma. Despite some setbacks and delays, the basic technology infrastructure was built, the alert system was implemented, nineteen practices focusing on diabetes improvement were recognized as patient-centered medical homes, and many participants agreed that the program had helped transform care. However, the experience also demonstrated that the ability to transfer data was limited in electronic health record systems; that considerable effort was required to adapt technology to support quality improvement; and that the ambitious agenda required more time for planning, training, and implementation than originally thought.

  11. Observations of inner plasmasphere irregularities with a satellite-beacon radio-interferometer array

    International Nuclear Information System (INIS)

    A radio-interferometer array illuminated by 136-MHz beacons of several geosynchronous satellites has been used to study small (≥1013 m-2) transient disturbances in the total electron content along the lines of sight to the satellites. High-frequency (f>3 mHz) electron content oscillations are persistently observed, particularly during night and particularly during geomagnetically disturbed periods. The oscillations move across the array plane at speeds in the range 200 endash 2000 m/s, with propagation azimuths that are strongly peaked in lobes toward the western half-plane. Detailed analysis of this azimuth behavior, involving comparison between observations on various satellite positions, indicates compellingly that the phase oscillations originate in radio refraction due to geomagnetically aligned plasma density perturbations in the inner plasmasphere. The motion of the phase perturbations across the array plane is caused by EXB drift of the plasma medium in which the irregularities are embedded. We review the statistics of 2.5 years of around-the-clock data on the local time, magnetic disturbance, seasonal, and line-of-sight variations of these observed irregularities. We compare the irregularities close-quote inferred electrodynamic drifts to what is known about midlatitude plasma drift from incoherent scatter. Finally, we show in detail how the observation of these irregularities provides a unique and complementary monitor of inner plasmasphere irregularity incidence and zonal drift.copyright 1996 American Geophysical Union

  12. A Catalytic Beacon Sensor for Uranium with Parts-per-Trillion Sensitivity and Millionfold Selectivity

    International Nuclear Information System (INIS)

    Here, we report a catalytic beacon sensor for uranyl (UO22+) based on an in vitro-selected UO22+-specific DNAzyme. The sensor consists of a DNA enzyme strand with a 3' quencher and a DNA substrate with a ribonucleotide adenosine (rA) in the middle and a fluorophore and a quencher at the 5' and 3' ends, respectively. The presence of UO22+ causes catalytic cleavage of the DNA substrate strand at the rA position and release of the fluorophore and thus dramatic increase of fluorescence intensity. The sensor has a detection limit of 11 parts per trillion (45 pM), a dynamic range up to 400 nM, and selectivity of >1-million-fold over other metal ions. The most interfering metal ion, Th(IV), interacts with the fluorescein fluorophore, causing slightly enhanced fluorescence intensity, with an apparent dissociation constant of ∼230 (micro)M. This sensor rivals the most sensitive analytical instruments for uranium detection, and its application in detecting uranium in contaminated soil samples is also demonstrated. This work shows that simple, cost-effective, and portable metal sensors can be obtained with similar sensitivity and selectivity as much more expensive and sophisticated analytical instruments. Such a sensor will play an important role in environmental remediation of radionuclides such as uranium

  13. Quantification of Salmonella Typhi in water and sediments by molecular-beacon based qPCR.

    Science.gov (United States)

    Rani, Neetika; Vajpayee, Poornima; Bhatti, Saurabh; Singh, Smriti; Shanker, Rishi; Gupta, Kailash Chand

    2014-10-01

    A molecular-beacon based qPCR assay targeting staG gene was designed for specific detection and quantification of S. Typhi and validated against water and sediment samples collected from the river Ganga, Yamuna and their confluence on two days during Mahakumbha mela 2012-2013 (a) 18 December, 2012: before six major religious holy dips (Makar Sankranti, Paush Poornima, Mauni Amavasya, Basant Panchami, Maghi Poornima and Mahashivratri) (b) 10 February, 2013: after the holy dip was taken by over 3,00,00,000 devotees led by ascetics of Hindu sects at Sangam on 'Mauni Amavasya' (the most auspicious day of ritualistic mass bathing). The assay could detect linearly lowest 1 genomic equivalent per qPCR and is highly sensitive and selective for S. Typhi detection in presence of non specific DNA from other bacterial strains including S. Paratyphi A and S. Typhimurium. It has been observed that water and sediment samples exhibit S. Typhi. The mass holy dip by devotees significantly affected the water and sediment quality by enhancing the number of S. Typhi in the study area. The qPCR developed in the study might be helpful in planning the intervention and prevention strategies for control of enteric fever outbreaks in endemic regions.

  14. Cleavable Molecular Beacon for Hg(2+) Detection Based on Phosphorothioate RNA Modifications.

    Science.gov (United States)

    Huang, Po-Jung Jimmy; Wang, Feng; Liu, Juewen

    2015-07-01

    Mercury is a highly toxic heavy metal, and detection of Hg(2+) by biosensors has attracted extensive research interest in the past decade. In particular, a number of DNA-based sensing strategies have been developed. Well-known examples include thymine-Hg(2+) interactions and Hg(2+)-activated DNAzymes. However, these mechanisms are highly dependent on buffer conditions or require hybridization with another DNA strand. Herein, we report a new mechanism based on Hg(2+)-induced cleavage of phosphorothioate (PS) modified RNA. Among the various metal ions tested, Hg(2+) induced the most significant cleavage (∼16%), while other metals cleaved less than 2% of the same substrate. The uncleaved substrate undergoes desulfurization in the presence of Hg(2+). This cleavage reaction yields a similar amount of product from pH 3.5 to 7 and in the temperature range between 20 and 90 °C. Various PS RNA junctions can be cleaved with a similar efficiency, but PS DNA junctions cannot be cleaved. A molecular beacon containing three PS RNA modifications is designed, detecting Hg(2+) down to 1.7 nM with excellent selectivity. This sensor can also detect Hg(2+) in the Lake Ontario water sample, although its response is significantly masked by fish tissues. PMID:26060876

  15. The keys to governance and stakeholder engagement: the southeast michigan beacon community case study.

    Science.gov (United States)

    Des Jardins, Terrisca R

    2014-01-01

    Community-based health information exchanges (HIEs) and efforts to consolidate and house data are growing, given the advent of Accountable Care Organizations (ACOs) under the Affordable Care Act and other similar population health focused initiatives. The Southeast Michigan Beacon Community (SEMBC) can be looked to as one case study that offers lessons learned, insights on challenges faced and accompanying workarounds related to governance and stakeholder engagement. The SEMBC case study employs an established Data Warehouse Governance Framework to identify and explain the necessary governance and stakeholder engagement components, particularly as they relate to community-wide data sharing and data warehouses or repositories. Perhaps the biggest lesson learned through the SEMBC experience is that community-based work is hard. It requires a great deal of community leadership, collaboration and resources. SEMBC found that organizational structure and guiding principles needed to be continually revisited and nurtured in order to build the relationships and trust needed among stakeholder organizations. SEMBC also found that risks and risk mitigation tactics presented challenges and opportunities at the outset and through the duration of the three year pilot period. Other communities across the country embarking on similar efforts need to consider realistic expectations about community data sharing infrastructures and the accompanying and necessary governance and stakeholder engagement fundamentals.

  16. Theranostic properties of a survivin-directed molecular beacon in human melanoma cells.

    Directory of Open Access Journals (Sweden)

    Sara Carpi

    Full Text Available Survivin is an inhibitor of apoptosis overexpressed in different types of tumors and undetectable in most terminally differentiated normal tissues. In the current study, we sought to evaluate the in vitro theranostic properties of a molecular beacon-oligodeoxynucleotide (MB that targets survivin mRNA. We used laser scanning confocal microscopy to study MB delivery in living cells and real-time PCR and western blot to assess selective survivin-targeting in human malignant melanoma cells. We further assess the pro-apoptotic effect of MB by measuring internucleosomal DNA fragmentation, dissipation of mitochondrial membrane potential (MMP and changes in nuclear morphology. Transfection of MB into A375 and 501 Mel cells generated high signal intensity from the cytoplasm, while no signal was detected in the extracellular environment and in survivin-negative cells (i.e., human melanocytes and monocytes. MB time dependently decreased survivin mRNA and protein expression in melanoma cells with the maximum effect reached at 72 h. Treatment of melanoma cells with MB induced apoptosis by significant changes in MMP, accumulation of histone-complexed DNA fragments in the cytoplasm and nuclear condensation. MB also enhanced the pro-apoptotic effect of standard chemotherapeutic drugs tested at clinically relevant concentrations. The MB tested in the current study conjugates the ability of imaging with the pharmacological silencing activity against survivin mRNA in human melanoma cells and may represent an innovative approach for cancer diagnosis and treatment.

  17. Electrochemical molecular beacon biosensor for sequence-specific recognition of double-stranded DNA.

    Science.gov (United States)

    Miao, Xiangmin; Guo, Xiaoting; Xiao, Zhiyou; Ling, Liansheng

    2014-09-15

    Direct recognition of double-stranded DNA (dsDNA) was crucial to disease diagnosis and gene therapy, because DNA in its natural state is double stranded. Here, a novel sensor for the sequence-specific recognition of dsDNA was developed based on the structure change of ferrocene (Fc) redox probe modified molecular beacon (MB). For constructing such a sensor, gold nanoparticles (AuNPs) were initially electrochemical-deposited onto glass carbon electrode (GCE) surface to immobilize thiolated MB in their folded states with Au-S bond. Hybridization of MB with target dsDNA induced the formation of parallel triplex DNA and opened the stem-loop structure of it, which resulted in the redox probe (Fc) away from the electrode and triggered the decrease of current signals. Under optimal conditions, dsDNA detection could be realized in the range from 350 pM to 25 nM, with a detection limit of 275 pM. Moreover, the proposed method has good sequence-specificity for target dsDNA compared with single base pair mismatch and two base pairs mismatches.

  18. A molecular beacon microarray based on a quantum dot label for detecting single nucleotide polymorphisms.

    Science.gov (United States)

    Guo, Qingsheng; Bai, Zhixiong; Liu, Yuqian; Sun, Qingjiang

    2016-03-15

    In this work, we report the application of streptavidin-coated quantum dot (strAV-QD) in molecular beacon (MB) microarray assays by using the strAV-QD to label the immobilized MB, avoiding target labeling and meanwhile obviating the use of amplification. The MBs are stem-loop structured oligodeoxynucleotides, modified with a thiol and a biotin at two terminals of the stem. With the strAV-QD labeling an "opened" MB rather than a "closed" MB via streptavidin-biotin reaction, a sensitive and specific detection of label-free target DNA sequence is demonstrated by the MB microarray, with a signal-to-background ratio of 8. The immobilized MBs can be perfectly regenerated, allowing the reuse of the microarray. The MB microarray also is able to detect single nucleotide polymorphisms, exhibiting genotype-dependent fluorescence signals. It is demonstrated that the MB microarray can perform as a 4-to-2 encoder, compressing the genotype information into two outputs.

  19. Rapid detection of infectious rotavirus group A using a molecular beacon assay.

    Science.gov (United States)

    Bertol, Jéssica Wildgrube; Gatti, Maria Silvia Viccari

    2016-08-01

    Rapid, sensitive and specific methods are necessary to detect and quantify infectious viruses. Cultivating and detecting enteric viruses in cell culture are difficult, thus impairing the advancement of knowledge regarding virus-induced diarrhea. Rotavirus (RV) detection has been conducted by serological or molecular biology methods, which do not provide information regarding viral infectivity. Molecular beacons (MBs) have demonstrated efficacy for viral detection in cell culture. We propose a MB assay to detect human rotavirus group A (HuRVA) in cell culture. MA104 cells were mock-infected or infected with HuRVA strains (RotaTeq(®) vaccine and K8 strains), and a specific MB for the HuRVA VP6 gene was used for virus detection. Mock-infected cells showed basal fluorescence, while infected cells exhibited increased fluorescence emission. MB hybridization to the viral mRNA target of HuRVA was confirmed. Fluorescence increased according to the increase in the number of infectious viral particles per cell (MOI 0.5-MOI 1). This technique provides quick and efficient HuRVA detection in cell culture without a need for viral culture for several days or many times until cytopathic effects are visualized. This methodology could be applied in the selection of samples for developing RV vaccines.

  20. With the Bible toward the year 2000: scriptural engagement as barometer, beacon and bellwether

    Directory of Open Access Journals (Sweden)

    J. H. Elliott

    1990-06-01

    Full Text Available Through the centuries, engagement with the Bible has served as a barometer (recording and reflec­ting the history of shifting circumstances, as a beacon (constituting a source of light illuminating theological reflection and guiding human conduct and as a bellwether (leading the way in setting new agendas for the Church, her theology and her encounter with the world. Against this back­ ground, the history of biblical engagement through the centuries is briefly traced. The main focus of the article is, however, to reflect on the role of the Bible in the next millenium. The author foresees an even stronger ecumenical engagement, an enhanced focus on a critical faith and a self-critical rationality, a stronger rejection of absolutist claims, renewed respect for the diversity of voices in the biblical canon, the emergence of biblical study to an attentive dialogue partner within other fields of human knowledge and a renewed search for wisdom in the Bible in future in order to face the problems which will confront humankind. Against the background of these developments the study of the Bible will, in the third millenium, become even more an interconfessional, international, interdisciplinary and intersocial enterprise, sustained by the conviction that the Bible is a holy and privileged word, both about human existence and humanity’s relation to God, society, history, and the cosmos.

  1. Rapid detection of infectious rotavirus group A using a molecular beacon assay.

    Science.gov (United States)

    Bertol, Jéssica Wildgrube; Gatti, Maria Silvia Viccari

    2016-08-01

    Rapid, sensitive and specific methods are necessary to detect and quantify infectious viruses. Cultivating and detecting enteric viruses in cell culture are difficult, thus impairing the advancement of knowledge regarding virus-induced diarrhea. Rotavirus (RV) detection has been conducted by serological or molecular biology methods, which do not provide information regarding viral infectivity. Molecular beacons (MBs) have demonstrated efficacy for viral detection in cell culture. We propose a MB assay to detect human rotavirus group A (HuRVA) in cell culture. MA104 cells were mock-infected or infected with HuRVA strains (RotaTeq(®) vaccine and K8 strains), and a specific MB for the HuRVA VP6 gene was used for virus detection. Mock-infected cells showed basal fluorescence, while infected cells exhibited increased fluorescence emission. MB hybridization to the viral mRNA target of HuRVA was confirmed. Fluorescence increased according to the increase in the number of infectious viral particles per cell (MOI 0.5-MOI 1). This technique provides quick and efficient HuRVA detection in cell culture without a need for viral culture for several days or many times until cytopathic effects are visualized. This methodology could be applied in the selection of samples for developing RV vaccines. PMID:27131514

  2. Entropy Beacon: A Hairpin-Free DNA Amplification Strategy for Efficient Detection of Nucleic Acids.

    Science.gov (United States)

    Lv, Yifan; Cui, Liang; Peng, Ruizi; Zhao, Zilong; Qiu, Liping; Chen, Huapei; Jin, Cheng; Zhang, Xiao-Bing; Tan, Weihong

    2015-12-01

    Here, we propose an efficient strategy for enzyme- and hairpin-free nucleic acid detection called an entropy beacon (abbreviated as Ebeacon). Different from previously reported DNA hybridization/displacement-based strategies, Ebeacon is driven forward by increases in the entropy of the system, instead of free energy released from new base-pair formation. Ebeacon shows high sensitivity, with a detection limit of 5 pM target DNA in buffer and 50 pM in cellular homogenate. Ebeacon also benefits from the hairpin-free amplification strategy and zero-background, excellent thermostability from 20 °C to 50 °C, as well as good resistance to complex environments. In particular, based on the huge difference between the breathing rate of a single base pair and two adjacent base pairs, Ebeacon also shows high selectivity toward base mutations, such as substitution, insertion, and deletion and, therefore, is an efficient nucleic acid detection method, comparable to most reported enzyme-free strategies.

  3. Quantification of Salmonella Typhi in water and sediments by molecular-beacon based qPCR.

    Science.gov (United States)

    Rani, Neetika; Vajpayee, Poornima; Bhatti, Saurabh; Singh, Smriti; Shanker, Rishi; Gupta, Kailash Chand

    2014-10-01

    A molecular-beacon based qPCR assay targeting staG gene was designed for specific detection and quantification of S. Typhi and validated against water and sediment samples collected from the river Ganga, Yamuna and their confluence on two days during Mahakumbha mela 2012-2013 (a) 18 December, 2012: before six major religious holy dips (Makar Sankranti, Paush Poornima, Mauni Amavasya, Basant Panchami, Maghi Poornima and Mahashivratri) (b) 10 February, 2013: after the holy dip was taken by over 3,00,00,000 devotees led by ascetics of Hindu sects at Sangam on 'Mauni Amavasya' (the most auspicious day of ritualistic mass bathing). The assay could detect linearly lowest 1 genomic equivalent per qPCR and is highly sensitive and selective for S. Typhi detection in presence of non specific DNA from other bacterial strains including S. Paratyphi A and S. Typhimurium. It has been observed that water and sediment samples exhibit S. Typhi. The mass holy dip by devotees significantly affected the water and sediment quality by enhancing the number of S. Typhi in the study area. The qPCR developed in the study might be helpful in planning the intervention and prevention strategies for control of enteric fever outbreaks in endemic regions. PMID:25042245

  4. Application of a molecular beacon based real-time isothermal amplification (MBRTIA) technology for simultaneous detection of Bacillus cereus and Staphylococcus aureus.

    Science.gov (United States)

    Mandappa, I M; Joglekar, Prasanna; Manonmani, H K

    2015-07-01

    A multiplex real-time isothermal amplification assay was developed using molecular beacons for the detection of Bacillus cereus and Staphylococcus aureus by targeting four important virulence genes. A correlation between targeting highly accessible DNA sequences and isothermal amplification based molecular beacon efficiency and sensitivity was demonstrated using phi(Φ)29 DNA polymerase at a constant isothermal temperature of 30 °C. It was very selective and consistently detected down to 10(1) copies of DNA. The specificity and sensitivity of this assay, when tested with pure culture were high, surpassing those of currently used PCR assays for the detection of these organisms. The molecular beacon based real-time isothermal amplification (MBRTIA) assay could be carried out entirely in 96 well plates or well strips, enabling a rapid and high-throughput detection of food borne pathogens.

  5. Beacons BLE (Bluetooth Low Energy) en el sector turístico, control de afluencia y servicios de valor añadido

    OpenAIRE

    Arregui Caballero de Tineo, Arkaitz

    2016-01-01

    Con la aparición del Bluetooth Smart y su bajo consumo, se ha abierto un nuevo abanico de posibilidades para las experiencias de proximidad. El uso de beacons Bluetooth Smart hace posible crear nuevas relaciones Proveedor-Usuario mediante la detección de usuarios que se acercan a una localización concreta. El bajo coste de los dispositivos BLE unido a la posibilidad de estar activo por largos periodos de tiempo con una pila de botón, permite marcar un lugar mediante un beacon con independenci...

  6. Study of fade and inter-fade durations in Ku- and Ka- band frequencies using OLYMPUS satellite beacons

    OpenAIRE

    Ajaz, Haroon

    1993-01-01

    Fade and inter-fade duration data obtained from the three beacons at 12, 20, and 30 GHz aboard the OLYMPUS satellite were analyzed. The different types of signal impairments and their causes were highlighted and a literature survey conducted. Twelve months of fade and inter-fade data were analyzed and the results of these statistics are presented in the form of tables and figures. The analysis was done on both the monthly and annual data. These tables and figures show that at t...

  7. Comparison of total electron content measurements made with the ATS-6 radio beacon over the U.S. and Europe

    International Nuclear Information System (INIS)

    ATS-6 radio beacon measurements made at three stations in the U.S.A. are compared and contrasted with similar measurements made in Europe the following year at two locations. It is shown that over the U.S.A. the winter plasmaspheric content reaches its maximum near 0300 LT whereas in Europe the maximum occurs near noon. The plasmaspheric content decreases with increase of magnetic activity in both continents. Winter night maxima are observed in ionospheric content in both hemispheres. Marked differences occurred in magnetic storm effects and in the day-to-night ratio of ionospheric electron content. (author)

  8. Beacon system based on light-emitting diode sources for runways lighting

    Science.gov (United States)

    Montes, Mario González; Vázquez, Daniel; Fernandez-Balbuena, Antonio A.; Bernabeu, Eusebio

    2014-06-01

    New aeronautical ground lighting techniques are becoming increasingly important to ensure the safety and reduce the maintenance costs of the plane's tracks. Until recently, tracks had embedded lighting systems whose sources were based on incandescent lamps. But incandescent lamps have several disadvantages: high energy consumption and frequent breakdowns that result in high maintenance costs (lamp average life-time is ˜1500 operating hours) and the lamp's technology has a lack of new lighting functions, such as signal handling and modification. To solve these problems, the industry has developed systems based on light-emitting diode (LED) technology with improved features: (1) LED lighting consumes one tenth the power, (2) it improves preventive maintenance (an LED's lifetime range is between 25,000 and 100,000 hours), and (3) LED lighting technology can be controlled remotely according to the needs of the track configuration. LEDs have been in use for more than three decades, but only recently, around 2002, have they begun to be used as visual aids, representing the greatest potential change for airport lighting since their inception in the 1920s. Currently, embedded LED systems are not being broadly used due to the specific constraints of the rules and regulations of airports (beacon dimensions, power system technology, etc.). The fundamental requirements applied to embedded lighting systems are to be hosted on a volume where the dimensions are usually critical and also to integrate all the essential components for operation. An embedded architecture that meets the lighting regulations for airport runways is presented. The present work is divided into three main tasks: development of an optical system to optimize lighting according to International Civil Aviation Organization, manufacturing prototype, and model validation.

  9. A Biofunctional Molecular Beacon for Detecting Single Base Mutations in Cancer Cells

    Science.gov (United States)

    Dong, Haiyan; Ma, Ji; Wang, Jie; Wu, Zai-Sheng; Sinko, Patrick J; Jia, Lee

    2016-01-01

    The development of a convenient and sensitive biosensing system to detect specific DNA sequences is an important issue in the field of genetic disease therapy. As a classic DNA detection technique, molecular beacon (MB) is often used in the biosensing system. However, it has intrinsic drawbacks, including high assay cost, complicated chemical modification, and operational complexity. In this study, we developed a simple and cost-effective label-free multifunctional MB (LMMB) by integrating elements of polymerization primer, template, target recognition, and G-quadruplex into one entity to detect target DNA. The core technique was accomplished by introducing a G-hairpin that features fragments of both G-quadruplex and target DNA recognition in the G-hairpin stem. Hybridization between LMMB and target DNA triggered conformational change between the G-hairpin and the common C-hairpin, resulting in significant SYBR-green signal amplification. The hybridization continues to the isothermal circular strand-displacement polymerization and accumulation of the double-stranded fragments, causing the uninterrupted extension of the LMMB without a need of chemical modification and other assistant DNA sequences. The novel and programmable LMMB could detect target DNA with sensitivity at 250 pmol/l with a linear range from 2 to 100 nmol/l and the relative standard deviation of 7.98%. The LMMB could sense a single base mutation from the normal DNA, and polymerase chain reaction (PCR) amplicons of the mutant-type cell line from the wild-type one. The total time required for preparation and assaying was only 25 minutes. Apparently, the LMMB shows great potential for detecting DNA and its mutations in biosamples, and therefore it opens up a new prospect for genetic disease therapy. PMID:27045206

  10. Ionospheric storm characteristics deduced from satellite radio beacon observations at three European stations

    International Nuclear Information System (INIS)

    Faraday rotation observations carried out at the stations Neustrelitz (53.30 N, 13.10 E), Graz (47.10 N, 15.50 E) and Florence (43.00 N, 10.70 E) by receiving the VHF beacon of the geostationary satellite SIRIO have been used to analyze more than hundred storm periods mainly on a statistical basis. Additionally, total electron content data obtained from differential Doppler measurements at NNSS satellite signals and vertical sounding data of the stations Dourbes (50.10 N, 4.60 E) and Rome (41.80 N, 12.50 E) are included in this analysis. The average response of the ionosphere shows an extended positive phase in winter whereas a well pronounced negative phase is typical for summer conditions. It is evident that the positive phase in electron content occurs in all seasons on the first storm day. The more pronounced storm effects in electron content than in f0 F2 indicate the important role of the upper ionosphere during storms. Further hints have been found for perturbations propagating equatorwards with seasonal dependent velocities accompanied by wind induced uplifting and mass transport of O2 and N2 leading to an enhanced loss of plasma. Immediately after SSC an eastward directed electric field is assumed to lift up the ionospheric plasma into regions of reduced loss. In general the storm associated percentage deviations of ionospheric electron content, F2 layer critical frequency, slab thickness as well as F2 layer height increase with enhanced geomagnetic activity

  11. G-Quadruplex DNAzyme Molecular Beacon for Amplified Colorimetric Biosensing of Pseudostellaria heterophylla

    Directory of Open Access Journals (Sweden)

    Juan Hu

    2013-01-01

    Full Text Available With an internal transcribed spacer of 18 S, 5.8 S and 26 S nuclear ribosomal DNA (nrDNA ITS as DNA marker, we report a colorimetric approach for authentication of Pseudostellaria heterophylla (PH and its counterfeit species based on the differentiation of the nrDNA ITS sequence. The assay possesses an unlabelled G-quadruplex DNAzyme molecular beacon (MB probe, employing complementary sequence as biorecognition element and 1:1:1:1 split G-quadruplex halves as reporter. In the absence of target DNA (T-DNA, the probe can shape intermolecular G-quadruplex structures capable of binding hemin to form G-quadruplex-hemin DNAzyme and catalyze the oxidation of ABTS2− to blue-green ABTS•− by H2O2. In the presence of T-DNA, T-DNA can hybridize with the complementary sequence to form a duplex structure, hindering the formation of the G-quadruplex structure and resulting in the loss of the catalytic activity. Consequently, a UV-Vis absorption signal decrease is observed in the ABTS2−-H2O2 system. The “turn-off” assay allows the detection of T-DNA from 1.0 × 10−9 to 3.0 × 10−7 mol·L−1 (R2 = 0.9906, with a low detection limit of 3.1 × 10−10 mol·L−1. The present study provides a sensitive and selective method and may serve as a foundation of utilizing the DNAzyme MB sensor for identifying traditional Chinese medicines.

  12. Theragnosis-based combined cancer therapy using doxorubicin-conjugated microRNA-221 molecular beacon.

    Science.gov (United States)

    Lee, Jonghwan; Choi, Kyung-Ju; Moon, Sung Ung; Kim, Soonhag

    2016-01-01

    Recently, microRNA (miRNA or miR) has emerged as a new cancer biomarker because of its high expression level in various cancer types and its role in the control of tumor suppressor genes. In cancer studies, molecular imaging and treatment based on target cancer markers have been combined to facilitate simultaneous cancer diagnosis and therapy. In this study, for combined therapy with diagnosis of cancer, we developed a doxorubicin-conjugated miR-221 molecular beacon (miR-221 DOXO MB) in a single platform composed of three different nucleotides: miR-221 binding sequence, black hole quencher 1 (BHQ1), and doxorubicin binding site. Imaging of endogenous miR-221 was achieved by specific hybridization between miR-221 and the miR-221 binding site in miR-221 DOXO MB. The presence of miR-221 triggered detachment of the quencher oligo and subsequent activation of a fluorescent signal of miR-221 DOXO MB. Simultaneous cancer therapy in C6 astrocytoma cells and nude mice was achieved by inhibition of miRNA-221 function that downregulates tumor suppressor genes. The detection of miR-221 expression and inhibition of miR-221 function by miR-221 DOXO MB provide the feasibility as a cancer theragnostic probe. Furthermore, a cytotoxic effect was induced by unloading of doxorubicin intercalated into miR-221 DOXO MB inside cells. Loss of miR-221 function and cytotoxicity induced by the miR-221 DOXO MB provides combined therapeutic efficacy against cancers. This method could be used as a new theragnostic probe with enhanced therapy to detect and inhibit many cancer-related miRNAs.

  13. A Biofunctional Molecular Beacon for Detecting Single Base Mutations in Cancer Cells.

    Science.gov (United States)

    Dong, Haiyan; Ma, Ji; Wang, Jie; Wu, Zai-Sheng; Sinko, Patrick J; Jia, Lee

    2016-01-01

    The development of a convenient and sensitive biosensing system to detect specific DNA sequences is an important issue in the field of genetic disease therapy. As a classic DNA detection technique, molecular beacon (MB) is often used in the biosensing system. However, it has intrinsic drawbacks, including high assay cost, complicated chemical modification, and operational complexity. In this study, we developed a simple and cost-effective label-free multifunctional MB (LMMB) by integrating elements of polymerization primer, template, target recognition, and G-quadruplex into one entity to detect target DNA. The core technique was accomplished by introducing a G-hairpin that features fragments of both G-quadruplex and target DNA recognition in the G-hairpin stem. Hybridization between LMMB and target DNA triggered conformational change between the G-hairpin and the common C-hairpin, resulting in significant SYBR-green signal amplification. The hybridization continues to the isothermal circular strand-displacement polymerization and accumulation of the double-stranded fragments, causing the uninterrupted extension of the LMMB without a need of chemical modification and other assistant DNA sequences. The novel and programmable LMMB could detect target DNA with sensitivity at 250 pmol/l with a linear range from 2 to 100 nmol/l and the relative standard deviation of 7.98%. The LMMB could sense a single base mutation from the normal DNA, and polymerase chain reaction (PCR) amplicons of the mutant-type cell line from the wild-type one. The total time required for preparation and assaying was only 25 minutes. Apparently, the LMMB shows great potential for detecting DNA and its mutations in biosamples, and therefore it opens up a new prospect for genetic disease therapy. PMID:27045206

  14. A Biofunctional Molecular Beacon for Detecting Single Base Mutations in Cancer Cells.

    Science.gov (United States)

    Dong, Haiyan; Ma, Ji; Wang, Jie; Wu, Zai-Sheng; Sinko, Patrick J; Jia, Lee

    2016-04-05

    The development of a convenient and sensitive biosensing system to detect specific DNA sequences is an important issue in the field of genetic disease therapy. As a classic DNA detection technique, molecular beacon (MB) is often used in the biosensing system. However, it has intrinsic drawbacks, including high assay cost, complicated chemical modification, and operational complexity. In this study, we developed a simple and cost-effective label-free multifunctional MB (LMMB) by integrating elements of polymerization primer, template, target recognition, and G-quadruplex into one entity to detect target DNA. The core technique was accomplished by introducing a G-hairpin that features fragments of both G-quadruplex and target DNA recognition in the G-hairpin stem. Hybridization between LMMB and target DNA triggered conformational change between the G-hairpin and the common C-hairpin, resulting in significant SYBR-green signal amplification. The hybridization continues to the isothermal circular strand-displacement polymerization and accumulation of the double-stranded fragments, causing the uninterrupted extension of the LMMB without a need of chemical modification and other assistant DNA sequences. The novel and programmable LMMB could detect target DNA with sensitivity at 250 pmol/l with a linear range from 2 to 100 nmol/l and the relative standard deviation of 7.98%. The LMMB could sense a single base mutation from the normal DNA, and polymerase chain reaction (PCR) amplicons of the mutant-type cell line from the wild-type one. The total time required for preparation and assaying was only 25 minutes. Apparently, the LMMB shows great potential for detecting DNA and its mutations in biosamples, and therefore it opens up a new prospect for genetic disease therapy.

  15. Theragnosis-based combined cancer therapy using doxorubicin-conjugated microRNA-221 molecular beacon.

    Science.gov (United States)

    Lee, Jonghwan; Choi, Kyung-Ju; Moon, Sung Ung; Kim, Soonhag

    2016-01-01

    Recently, microRNA (miRNA or miR) has emerged as a new cancer biomarker because of its high expression level in various cancer types and its role in the control of tumor suppressor genes. In cancer studies, molecular imaging and treatment based on target cancer markers have been combined to facilitate simultaneous cancer diagnosis and therapy. In this study, for combined therapy with diagnosis of cancer, we developed a doxorubicin-conjugated miR-221 molecular beacon (miR-221 DOXO MB) in a single platform composed of three different nucleotides: miR-221 binding sequence, black hole quencher 1 (BHQ1), and doxorubicin binding site. Imaging of endogenous miR-221 was achieved by specific hybridization between miR-221 and the miR-221 binding site in miR-221 DOXO MB. The presence of miR-221 triggered detachment of the quencher oligo and subsequent activation of a fluorescent signal of miR-221 DOXO MB. Simultaneous cancer therapy in C6 astrocytoma cells and nude mice was achieved by inhibition of miRNA-221 function that downregulates tumor suppressor genes. The detection of miR-221 expression and inhibition of miR-221 function by miR-221 DOXO MB provide the feasibility as a cancer theragnostic probe. Furthermore, a cytotoxic effect was induced by unloading of doxorubicin intercalated into miR-221 DOXO MB inside cells. Loss of miR-221 function and cytotoxicity induced by the miR-221 DOXO MB provides combined therapeutic efficacy against cancers. This method could be used as a new theragnostic probe with enhanced therapy to detect and inhibit many cancer-related miRNAs. PMID:26454049

  16. Exciton interaction in molecular beacons: a sensitive sensor for short range modifications of the nucleic acid structure.

    Science.gov (United States)

    Bernacchi, S; Mély, Y

    2001-07-01

    Molecular beacons are hairpin-shaped, single-stranded oligonucleotides constituting sensitive fluorescent DNA probes widely used to report the presence of specific nucleic acids. In its closed form the stem of the hairpin holds the fluorophore covalently attached to one end, close to the quencher, which is covalently attached to the other end. Here we report that in the closed form the fluorophore and the quencher form a ground state intramolecular heterodimer whose spectral properties can be described by exciton theory. Formation of the heterodimers was found to be poorly sensitive to the stem sequence, the respective positions of the dyes and the nature of the nucleic acid (DNA or RNA). The heterodimer allows strong coupling between the transition dipoles of the two chromophores, leading to dramatic changes in the absorption spectrum that are not compatible with a Förster-type fluorescence resonance energy transfer (FRET) mechanism. The excitonic heterodimer and its associated absorption spectrum are extremely sensitive to the orientation of and distance between the dyes. Accordingly, the application of molecular beacons can be extended to monitoring short range modifications of the stem structure. Moreover, the excitonic interaction was also found to operate for doubly end-labeled duplexes. PMID:11433038

  17. Direct detection of circulating free DNA extracted from serum samples of breast cancer using locked nucleic acid molecular beacon.

    Science.gov (United States)

    Gui, Zhen; Wang, Quanbo; Li, Jinchang; Zhu, Mingchen; Yu, Lili; Xun, Tang; Yan, Feng; Ju, Huangxian

    2016-07-01

    As an emerging noninvasive blood biomarker, circulating free DNA (cfDNA) can be utilized to assess diagnosis, progression and evaluate prognosis of cancer. However, cfDNAs are not "naked", they can be part of complexes, or are bound to the surface of the cells via proteins, which make the detection more challenging. Here, a simple method for the detection of Ubiquitin-like with PHD and ring finger domains 1 (UHRF1) DNA exacted from serum of breast cancer (BC) has been developed using a novel locked nucleic acid molecular beacon (LNA-MB). In order to enhance the stability and detection efficiency of the probe in biofluids, we design a shared-stem molecular beacon containing a 27-mer loop and a 4-mer stem with DNA/LNA alternating bases. The fluorescence is released in the presence of target. The detection procedure is simple and can be completed within 1h. This method shows a sensitive response to UHRF1 DNA with a dynamic range of 3 orders of magnitude. The limit of detection is 11nM (S/N=3) with excellent selectivity. It can discriminate UHRF1 DNA from three-base mismatched DNA with a high specificity. More importantly, this method can distinguish the expression of serum UHRF1 DNA among 5 breast cancer patients and 5 healthy controls. The mentioned superiority may suggest that this assay can be served as a promising noninvasive detection tool for early BC diagnosis and monitoring.

  18. High-energy all-solid-state sodium beacon laser with line width of 0.6 GHz

    Science.gov (United States)

    Lu, Yan-Hua; Xie, Gang; Zhang, Lei; Fan, Guo-Bin; Pang, Yu; Li, Nan; Wei, Bin; Gao, Song-Xin; Zhang, Wei; Tang, Chun

    2015-02-01

    A high-energy all-solid-state sodium beacon laser at 589 nm with a repetition rate of 50 Hz is introduced, which is based on sum frequency mixing between a 1,064 nm laser and a 1,319 nm laser. The 1,064 nm laser, which features an external modulated CW seed laser and several stages of amplifiers, can provide pulse energy of 740 mJ with ultra-narrow line width (~17 kHz) and superior stability. The 1,319 nm laser can deliver pulse energy of 580 mJ with a narrow line width of 0.6 GHz. By sum frequency mixing in a LBO crystal, pulse energy of 380 mJ is achieved at 589 nm with a conversion efficiency of 29 %. By controlling the center wavelength of 1,064 nm laser, the target beam's central wavelength is locked to be 589.1592 nm with a line width of 0.6 GHz, which is dominated mainly by the 1,319 nm laser. The beam quality factor is measured to be M 2 = 1.6. The pulse duration is measured to be 140 μs in full-width at half-maximum (FWHM). To the best of our knowledge, this represents the highest pulse energy for all-solid-state sodium beacon laser ever reported.

  19. Direct detection of circulating free DNA extracted from serum samples of breast cancer using locked nucleic acid molecular beacon.

    Science.gov (United States)

    Gui, Zhen; Wang, Quanbo; Li, Jinchang; Zhu, Mingchen; Yu, Lili; Xun, Tang; Yan, Feng; Ju, Huangxian

    2016-07-01

    As an emerging noninvasive blood biomarker, circulating free DNA (cfDNA) can be utilized to assess diagnosis, progression and evaluate prognosis of cancer. However, cfDNAs are not "naked", they can be part of complexes, or are bound to the surface of the cells via proteins, which make the detection more challenging. Here, a simple method for the detection of Ubiquitin-like with PHD and ring finger domains 1 (UHRF1) DNA exacted from serum of breast cancer (BC) has been developed using a novel locked nucleic acid molecular beacon (LNA-MB). In order to enhance the stability and detection efficiency of the probe in biofluids, we design a shared-stem molecular beacon containing a 27-mer loop and a 4-mer stem with DNA/LNA alternating bases. The fluorescence is released in the presence of target. The detection procedure is simple and can be completed within 1h. This method shows a sensitive response to UHRF1 DNA with a dynamic range of 3 orders of magnitude. The limit of detection is 11nM (S/N=3) with excellent selectivity. It can discriminate UHRF1 DNA from three-base mismatched DNA with a high specificity. More importantly, this method can distinguish the expression of serum UHRF1 DNA among 5 breast cancer patients and 5 healthy controls. The mentioned superiority may suggest that this assay can be served as a promising noninvasive detection tool for early BC diagnosis and monitoring. PMID:27154709

  20. Screening mTOR siRNA based on bioinformatics and detecting the transcription by the gold nanoparticle beacon

    Science.gov (United States)

    Tian, Caiping; Ma, Yi; Li, Siwen; Gu, Yueqing

    2014-09-01

    Mammalian target of rapamycin (mTOR) as a key protein in PI3K-AKT-mTOR signaling pathway ,plays an important role in the tumor growth. The small interfering RNA (siRNA) of mTOR would decrease the expression of mTOR protein. In this study, we screened the mTOR siRNA sequence using MATLAB software and ascertained it based on BLAST. Then we imported it with the aid of Lipofectamine2000 into MCF-7 cancer cells where mTOR is over expression .And then we used a special hairpin deoxyribonucleic acid (DNA) for combining with the human mTOR mRNA to functionalize gold nanoparticles, which served as a molecule beacon for detecting human mTOR mRNA transcription. Laser scanning confocal microscope and Flow Cytometry data showed that the quenching efficiency was up to 90%,which are consistent with the RT-PCR measurement and Western. Compared to the previous approaches, this beacon has advantages of higher target to background ratio of detection. The strategy reported in this study is a promising approach for the intracellular measurement of the result of siRNA or protein expression in living cells, and has great potential in the study of drug screening and discovery.

  1. BEACON/MOD2A: a computer program for subcompartment analysis of nuclear reactor containment. A user's manual. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Wells, R. A.

    1979-03-01

    The BEACON code is a Best Estimate Advanced Containment code which being developed by EG and G, Idaho, Inc., at the Idaho National Engineering Laboratory. The program is designed to perform a best estimate analysis of the flow of a mixture of air, water, and steam in a nuclear reactor containment system under loss-of-coolant accident conditions. The code can simulate two-component, two-phase fluid flow in complex geometries using a combination of two-dimensional, one-dimensional, and lumped-parameter representations for the various parts of the system. The current version of BEACON, which is designated BEACON/MOD2A, contains mass and heat transfer models for wall film and for wall conduction. It is suitable for the evaluation of short term transients in PWR dry containment systems. This manual describes the models employed in BEACON/MOD2A and specifies code implementation requirements. It provides application information for input data preparation and for output data interpretation.

  2. SOX2 and OCT4 mRNA-Expressing Cells, Detected by Molecular Beacons, Localize to the Center of Neurospheres during Differentiation

    DEFF Research Database (Denmark)

    Ilieva, Mirolyuba; Dufva, Martin

    2013-01-01

    Neurospheres are used as in vitro assay to measure the properties of neural stem cells. To investigate the molecular and phenotypic heterogeneity of neurospheres, molecular beacons (MBs) targeted against the stem cell markers OCT4 and SOX2 were designed, and synthesized with a 2'-O-methyl RNA...

  3. 基于随机信标的水下 SLAM 导航方法%Underwater SLAM navigation algorithm based on random beacons

    Institute of Scientific and Technical Information of China (English)

    刘明雍; 董婷婷; 张立川

    2015-01-01

    研究了基于随机信标的水下同时制图定位(simultaneous localization and mapping,SLAM)导航定位方法。信标导航是目前导航领域的研究热点,但往往需要提前对信标位置进行标定。对此文中提出一种无需位置标定的随机信标导航方法,即在信标随机散布的情况下,通过量测信标和航行器间的距离和方位,用 SLAM 方法对随机信标位置进行估计,从而实现对航行器的导航,并在不同的信标密度和观测误差下分析了其导航精度。仿真结果表明,该导航方法具有良好的收敛性和定位精度。%An underwater simultaneous localization and mapping (SLAM)navigation algorithm based on random beacons is studied.At present,beacon navigation is extensively studied in the field of navigation,but it often needs to locate the beacon’s positon in advance.In this paper,we propose a navigation method based on random beacons that does not need position calibration,that is,when beacons are randomly dispersed,we use the SLAM method to estimate the position of the random beacons,thus to navigate the autonomous underwater vehicle (AUV)by observing the distance and orientation between the beacons and the AUV.We also analyze the navigation accuracy under different beacons density and different observation errors.Simulation results show that the algorithm performs well in both convergence and precision.

  4. BlueDetect: An iBeacon-Enabled Scheme for Accurate and Energy-Efficient Indoor-Outdoor Detection and Seamless Location-Based Service.

    Science.gov (United States)

    Zou, Han; Jiang, Hao; Luo, Yiwen; Zhu, Jianjie; Lu, Xiaoxuan; Xie, Lihua

    2016-01-01

    The location and contextual status (indoor or outdoor) is fundamental and critical information for upper-layer applications, such as activity recognition and location-based services (LBS) for individuals. In addition, optimizations of building management systems (BMS), such as the pre-cooling or heating process of the air-conditioning system according to the human traffic entering or exiting a building, can utilize the information, as well. The emerging mobile devices, which are equipped with various sensors, become a feasible and flexible platform to perform indoor-outdoor (IO) detection. However, power-hungry sensors, such as GPS and WiFi, should be used with caution due to the constrained battery storage on mobile device. We propose BlueDetect: an accurate, fast response and energy-efficient scheme for IO detection and seamless LBS running on the mobile device based on the emerging low-power iBeacon technology. By leveraging the on-broad Bluetooth module and our proposed algorithms, BlueDetect provides a precise IO detection service that can turn on/off on-board power-hungry sensors smartly and automatically, optimize their performances and reduce the power consumption of mobile devices simultaneously. Moreover, seamless positioning and navigation services can be realized by it, especially in a semi-outdoor environment, which cannot be achieved by GPS or an indoor positioning system (IPS) easily. We prototype BlueDetect on Android mobile devices and evaluate its performance comprehensively. The experimental results have validated the superiority of BlueDetect in terms of IO detection accuracy, localization accuracy and energy consumption. PMID:26907295

  5. BlueDetect: An iBeacon-Enabled Scheme for Accurate and Energy-Efficient Indoor-Outdoor Detection and Seamless Location-Based Service

    Directory of Open Access Journals (Sweden)

    Han Zou

    2016-02-01

    Full Text Available The location and contextual status (indoor or outdoor is fundamental and critical information for upper-layer applications, such as activity recognition and location-based services (LBS for individuals. In addition, optimizations of building management systems (BMS, such as the pre-cooling or heating process of the air-conditioning system according to the human traffic entering or exiting a building, can utilize the information, as well. The emerging mobile devices, which are equipped with various sensors, become a feasible and flexible platform to perform indoor-outdoor (IO detection. However, power-hungry sensors, such as GPS and WiFi, should be used with caution due to the constrained battery storage on mobile device. We propose BlueDetect: an accurate, fast response and energy-efficient scheme for IO detection and seamless LBS running on the mobile device based on the emerging low-power iBeacon technology. By leveraging the on-broad Bluetooth module and our proposed algorithms, BlueDetect provides a precise IO detection service that can turn on/off on-board power-hungry sensors smartly and automatically, optimize their performances and reduce the power consumption of mobile devices simultaneously. Moreover, seamless positioning and navigation services can be realized by it, especially in a semi-outdoor environment, which cannot be achieved by GPS or an indoor positioning system (IPS easily. We prototype BlueDetect on Android mobile devices and evaluate its performance comprehensively. The experimental results have validated the superiority of BlueDetect in terms of IO detection accuracy, localization accuracy and energy consumption.

  6. WSN定位算法中信标节点的摆放与选择%Placement and Selection Algorithm of Beacon Nodes in WSN Localization

    Institute of Scientific and Technical Information of China (English)

    樊爱京; 朱小艳; 郭拯危; 李辉

    2012-01-01

    目前已有的无线传感器网络节点自定位算法研究中,针对信标节点的研究较少,而如何选择信标节点,以及信标节点如何摆放,都对定位精度有比较大的影响.为了定量地研究这个问题,首先证明了信标节点摆放方法与节点是否能被定位之间的关系的一个定理,然后给出三维空间中信标节点的摆放方法,最后提出一种基于线性方程组的条件数的信标节点选择算法,以便尽可能地提高基于测距的未知节点自定位精度.%Currently, few studies of wireless sensor network node localization algorithm were focused on the beacon nodes, but how to choose and place the beacon nodes has a large impact on the positioning accuracy. In order to quantitatively study this issue, a theorem was proved that offers a desiription of the relationship between the placement of beacon nodes and whether the unknown node could be located, then the beacon nodes placement method was designed. Finally, a beacon nodes selection algorithm was proposed based on the condition number of linear equations, so as to improve the accuracy of range-based localization algorithm.

  7. Plasmaspheric electron content variation in the magnetic equatorial region during space weather events: Results from the CRABEX (Coherent Radio Beacon Experiment) using the beacon onboard the Indian geostationary satellite (GSAT - 2)

    Science.gov (United States)

    Ravindran, Sudha; Manju, G.; Devasia, C. V.; Sridharan, R.; Thampi, S. V.; Sreelatha, P.; Sreeja, V.; Pant, T. K.; Raghava Reddi, C.

    CRABEX is a national scientific program for the investigation of the unique features associated with the equatorial and low latitude ionosphere in the Indian zone using the technique of ionospheric tomography It consists of a beacon transmitter onboard the Indian geostationary satellite GSAT-2 which transmits four coherently generated frequencies - 150 012MHz 400 032MHz along with 1 MHz modulation of these frequencies i e 149 01192 MHz and 399 03192 MHz and a unique ground receiver system designed and set up at Trivandrum dip 0 3 r N to receive these beacon transmissions The data obtained from the measurement of the differential phase between 400 MHz and 150 MHz gives the relative Total Electron Content TEC along the line of sight between the satellite and the ground receiver and the measurement of modulation phase delay of 1 MHz on the above frequencies provides a coarse estimate of TEC These two measurements together give an accurate estimate of TEC along the line of sight from the satellite to the ground receiver and the Faraday rotation measurements give a reliable estimate of electron content upto sim 2000 km i e the ionospheric content IEC The simultaneous measurements of IEC and TEC upto the geo-stationary altitude of 36000 km is used to determine the plasmaspheric electron content PEC The CRABEX program with its another segment consisting of a network of 6 receiver stations over the Indian subcontinent established along 77-78 r E meridian also makes use of the data obtained by receiving the 150 and 400 MHz

  8. BEACON/MOD3, 1-D and 2-D 2 Phase Flow and Heat Transfer in Containment, LWR LOCA

    International Nuclear Information System (INIS)

    1 - Description of problem or function: The BEACON series of programs is designed to perform a best-estimate analysis of the flow of a mixture of air, water, and steam in a nuclear reactor containment system under loss-of-coolant accident conditions. The code can simulate two-component, two-phase fluid flow in complex geometries using a combination of two-dimensional, one-dimensional, and lumped- parameter representations for the various parts of the system. BEACON/MOD3 contains mass and heat transfer models for wall film and for wall conduction, and is suitable for the evaluation of short- term transients in PWR dry containment systems. The capability to examine the details of a two-components, two-phase flow field in one or two dimensions under nonhomogeneous, nonequilibrium conditions (unequal velocities, unequal temperatures between the two phases) allows analysis of such problems as the calculation of jet impact forces of a fluid leaving a pipe break, the motion of a large pressure wave across a compartment, the variation in flow properties as air is displaced from a compartment by steam and water, the water entrainment or de-entrainment by a high-speed vapor flow, the flow of a flashing liquid, and many other complex nonequilibrium problems of containment system analyses. 2 - Method of solution: The basic Eulerian flow solution procedure is based on the K-FIX two-dimensional two-phase numerical method. Each phase is described by its own density, velocity, and temperature as determined by separate sets of mass, momentum, and energy equations. The two phases are coupled by exchange parameters which model the exchange of mass, momentum, and energy between the two phases. The two sets of field equations are solved with a Eulerian finite- difference technique that implicitly treats the phase transitions and inter-phasic heat transfer in the pressure iteration. The implicit solution is accomplished iteratively without linearization and allows both phases to be

  9. Proposal of a new generation of Laser Beacon for time calibration in the KM3NeT neutrino telescope

    International Nuclear Information System (INIS)

    The KM3NeT collaboration aims at the construction of a multi-km3 high-energy neutrino telescope in the Mediterranean Sea consisting of a matrix of pressure resistant glass spheres holding each a set (31) of small area photomultipliers. The main motivation of the telescope is to observe cosmic neutrinos through the Cherenkov light induced in sea water by charged particles produced in neutrino interactions with the surrounding medium. A relative time calibration between photomultipliers of the order of 1 ns is required to achieve an optimal performance. To this end, several time calibration subsystems have been developed. In this article, the proposal of a last generation Laser Beacon, to be used in KM3NeT and developed to measure and monitor the relative time offsets between photomultipliers, is presented

  10. A solid-state electrochemiluminescence biosensing switch for detection of DNA hybridization based on ferrocene-labeled molecular beacon

    International Nuclear Information System (INIS)

    A solid-state electrochemiluminescence (ECL) biosensing switch incorporating quenching of ECL of ruthenium(II) tris-(bipyridine) (Ru(bpy)32+) by ferrocene (Fc) has been successfully developed for DNA hybridization detection. The important issue for this biosensing system is based on the ferrocene-labeled molecular beacon (Fc-MB), i.e. using the special Fc-MB to react with the target DNA and then change its structure, resulting in an ECL intensity change. Under the optimal conditions, the difference of ECL intensity before and after the hybridization reaction (ΔIECL) was linearly related to the concentration of the complementary sequence in the range of 10 fM-10 pM and the detection limit was down to 1.0 fM.

  11. "Molecular beacon"-hosted thioflavin T: Applications for label-free fluorescent detection of iodide and logic operations.

    Science.gov (United States)

    Li, Yan-Yun; Jiang, Xiao-Qin; Lu, Ling-Fei; Zhang, Min; Shi, Guoyue

    2016-04-01

    In this work, we presented a simple, label-free and rapid-responsive fluorescence assay for iodide (I(-)) detection based on "molecular beacon (MB)"-hosted thioflavin T (ThT), achieving a limit of detection as low as 158 nM. The proposed method exhibited very good selectivity to I(-) ions over other anions interference due to the strong binding force between I(-) ions with Hg(2+). Upon the addition of I(-) ions, it would capture Hg(2+) from a T-Hg(2+)-T complex belonging to the MB-like DNA hairpin structure, which eventually quenched the initial fluorescence as output. In addition, it was successfully applied for operation of an integrated DNA logic gate system and to the determination of I(-) in real samples such as human urine. PMID:26838450

  12. Laser diode-fiber link for the transmitter of the SOUT program and for the beacon of the Silex program

    Science.gov (United States)

    Malaise, Daniel; Gollier, Jacques

    1993-06-01

    The small optical user terminal (SOUT) is part of an experimental program of the European Space Agency, initiated by British Aerospace. One takes advantage of the high antenna gain obtainable at 830 nm to build a very small, lightweight, and comparatively low cost terminal, capable of communicating with SILEX, ESA's full scale optical telecommunication program. SPACEBEL is in charge of developing the transmitting chain of the SOUT, and demonstrating its performances on a breadboard model. In the first part of the paper, we describe the transmitting chain of SOUT, stressing the delicate optical link between the diode and the monomode fiber. In the second part of the paper, we report on the first measurement of the efficiency of the coupling between the laser diode and the fiber as measured on the engineering model of the flight design for the Silex Beacon.

  13. Proposal of a new generation of Laser Beacon for time calibration in the KM3NeT neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Real, Diego [IFIC, Instituto de Física Corpuscular, CSIC-Universidad de Valencia, C/Catedrático José Beltrán, 2. 46980 Paterna (Spain); Collaboration: KM3NeT Collaboration

    2014-11-18

    The KM3NeT collaboration aims at the construction of a multi-km3 high-energy neutrino telescope in the Mediterranean Sea consisting of a matrix of pressure resistant glass spheres holding each a set (31) of small area photomultipliers. The main motivation of the telescope is to observe cosmic neutrinos through the Cherenkov light induced in sea water by charged particles produced in neutrino interactions with the surrounding medium. A relative time calibration between photomultipliers of the order of 1 ns is required to achieve an optimal performance. To this end, several time calibration subsystems have been developed. In this article, the proposal of a last generation Laser Beacon, to be used in KM3NeT and developed to measure and monitor the relative time offsets between photomultipliers, is presented.

  14. "Molecular beacon"-hosted thioflavin T: Applications for label-free fluorescent detection of iodide and logic operations.

    Science.gov (United States)

    Li, Yan-Yun; Jiang, Xiao-Qin; Lu, Ling-Fei; Zhang, Min; Shi, Guoyue

    2016-04-01

    In this work, we presented a simple, label-free and rapid-responsive fluorescence assay for iodide (I(-)) detection based on "molecular beacon (MB)"-hosted thioflavin T (ThT), achieving a limit of detection as low as 158 nM. The proposed method exhibited very good selectivity to I(-) ions over other anions interference due to the strong binding force between I(-) ions with Hg(2+). Upon the addition of I(-) ions, it would capture Hg(2+) from a T-Hg(2+)-T complex belonging to the MB-like DNA hairpin structure, which eventually quenched the initial fluorescence as output. In addition, it was successfully applied for operation of an integrated DNA logic gate system and to the determination of I(-) in real samples such as human urine.

  15. In vitro RNA release from a human rhinovirus monitored by means of a molecular beacon and chip electrophoresis.

    Science.gov (United States)

    Weiss, Victor U; Bliem, Christina; Gösler, Irene; Fedosyuk, Sofiya; Kratzmeier, Martin; Blaas, Dieter; Allmaier, Günter

    2016-06-01

    Liquid-phase electrophoresis either in the classical capillary format or miniaturized (chip CE) is a valuable tool for quality control of virus preparations and for targeting questions related to conformational changes of viruses during infection. We present an in vitro assay to follow the release of the RNA genome from a human rhinovirus (common cold virus) by using a molecular beacon (MB) and chip CE. The MB, a probe that becomes fluorescent upon hybridization to a complementary sequence, was designed to bind close to the 3' end of the viral genome. Addition of Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a well-known additive for reduction of bleaching and blinking of fluorophores in fluorescence microscopy, to the background electrolyte increased the sensitivity of our chip CE set-up. Hence, a fast, sensitive and straightforward method for the detection of viral RNA is introduced. Additionally, challenges of our assay will be discussed. In particular, we found that (i) desalting of virus preparations prior to analysis increased the recorded signal and (ii) the MB-RNA complex signal decreased with the time of virus storage at -70 °C. This suggests that 3'-proximal sequences of the viral RNA, if not the whole genome, underwent degradation during storage and/or freezing and thawing. In summary, we demonstrate, for two independent virus batches, that chip electrophoresis can be used to monitor MB hybridization to RNA released upon incubation of the native virus at 56 °C. Graphical Abstract Schematic of the study strategy: RNA released from HRV-A2 is detected by chip electrophoresis through the increase in fluorescence after genom complexation to a cognate molecular beacon.

  16. Gastroesophageal reflux in relation to adenocarcinomas of the esophagus: a pooled analysis from the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON.

    Directory of Open Access Journals (Sweden)

    Michael B Cook

    Full Text Available Previous studies have evidenced an association between gastroesophageal reflux and esophageal adenocarcinoma (EA. It is unknown to what extent these associations vary by population, age, sex, body mass index, and cigarette smoking, or whether duration and frequency of symptoms interact in predicting risk. The Barrett's and Esophageal Adenocarcinoma Consortium (BEACON allowed an in-depth assessment of these issues.Detailed information on heartburn and regurgitation symptoms and covariates were available from five BEACON case-control studies of EA and esophagogastric junction adenocarcinoma (EGJA. We conducted single-study multivariable logistic regressions followed by random-effects meta-analysis. Stratified analyses, meta-regressions, and sensitivity analyses were also conducted.Five studies provided 1,128 EA cases, 1,229 EGJA cases, and 4,057 controls for analysis. All summary estimates indicated positive, significant associations between heartburn/regurgitation symptoms and EA. Increasing heartburn duration was associated with increasing EA risk; odds ratios were 2.80, 3.85, and 6.24 for symptom durations of <10 years, 10 to <20 years, and ≥20 years. Associations with EGJA were slighter weaker, but still statistically significant for those with the highest exposure. Both frequency and duration of heartburn/regurgitation symptoms were independently associated with higher risk. We observed similar strengths of associations when stratified by age, sex, cigarette smoking, and body mass index.This analysis indicates that the association between heartburn/regurgitation symptoms and EA is strong, increases with increased duration and/or frequency, and is consistent across major risk factors. Weaker associations for EGJA suggest that this cancer site has a dissimilar pathogenesis or represents a mixed population of patients.

  17. In vitro RNA release from a human rhinovirus monitored by means of a molecular beacon and chip electrophoresis.

    Science.gov (United States)

    Weiss, Victor U; Bliem, Christina; Gösler, Irene; Fedosyuk, Sofiya; Kratzmeier, Martin; Blaas, Dieter; Allmaier, Günter

    2016-06-01

    Liquid-phase electrophoresis either in the classical capillary format or miniaturized (chip CE) is a valuable tool for quality control of virus preparations and for targeting questions related to conformational changes of viruses during infection. We present an in vitro assay to follow the release of the RNA genome from a human rhinovirus (common cold virus) by using a molecular beacon (MB) and chip CE. The MB, a probe that becomes fluorescent upon hybridization to a complementary sequence, was designed to bind close to the 3' end of the viral genome. Addition of Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a well-known additive for reduction of bleaching and blinking of fluorophores in fluorescence microscopy, to the background electrolyte increased the sensitivity of our chip CE set-up. Hence, a fast, sensitive and straightforward method for the detection of viral RNA is introduced. Additionally, challenges of our assay will be discussed. In particular, we found that (i) desalting of virus preparations prior to analysis increased the recorded signal and (ii) the MB-RNA complex signal decreased with the time of virus storage at -70 °C. This suggests that 3'-proximal sequences of the viral RNA, if not the whole genome, underwent degradation during storage and/or freezing and thawing. In summary, we demonstrate, for two independent virus batches, that chip electrophoresis can be used to monitor MB hybridization to RNA released upon incubation of the native virus at 56 °C. Graphical Abstract Schematic of the study strategy: RNA released from HRV-A2 is detected by chip electrophoresis through the increase in fluorescence after genom complexation to a cognate molecular beacon. PMID:27020928

  18. 基于复合信标的农田节点定位研究%Research on Farmland Node Localization based on Complex Beacon

    Institute of Scientific and Technical Information of China (English)

    田淑梅; 张喜海; 廉龙颖; 宋一弘

    2013-01-01

      及时准确的采集农田信息是精准农业的关键,节点定位问题也因此成为农田无线传感网络应用的核心问题,为解决此问题,这里提出了固定信标与移动信标的复合信标节点定位方法。使用装有 GPS或其他定位系统的移动装置,作为移动信标节点,同时在传感监控区域内加入不同数量的固定信标节点。该复合信标节点定位方法有效的提高了节点定位精度,同时提高了节点覆盖率。采用加权最小二乘法与扩展卡尔曼滤波相结合的算法,通过仿真结果分析了随着信标数的增多,平均定位误差明显减小;同时通过增大初始状态误差斜方差阵,可以很好抑制增大的初始误差对 EKF 滤波精度的影响。%Timely and correct acquisition of field information is the key to implementing precision agriculture, and node localization thus becomes the core of farmland WSN (wireless sensor network) application. A complex beacon node localization in combination of fixed beacons and mobile beacons is proposed in this paper. By using mobile devices with GPS or other positioning system as mobile beacon node while adding different numbers of fixed beacon nodes to the sensing network, this localization algorithm could raise the coverage rate of network node and positioning accuracy effectively. Simulation indicates that this algorithm, in combination of weighted least squares estimation with EKF (Extended-Kalman Filter) could significantly reduce the average location error with the increasing of beacon numbers. Meanwile, the effect of the increasing initial error on accuracy of EKF filter could be efficiently constrained with the expansion of error oblique variance matrix.

  19. 基于iBeacon的精细室内定位方法研究%Research on Elaborate Indoor Positioning Method Based on iBeacon Firmware

    Institute of Scientific and Technical Information of China (English)

    张倬胜; 马方方; 薛静远; 艾浩军

    2015-01-01

    苹果公司发布的iBeacon作为一种粗精度位置感知服务体系,得到了广泛关注。针对更精细的广域位置服务,提出了基于iBeacon的无线指纹定位方法,并给出了图书馆的位置服务示例。%Apple released iBeacon as a rough-precision position sensing distance service system, it has attracted extensive attention. For more sophisticated wide-area location services, wireless fingerprinting positioning method is proposed based on iBeacon, and an example of location based service system of library is given.

  20. In-cell protease assay systems based on trans-localizing molecular beacon proteins using HCV protease as a model system.

    Directory of Open Access Journals (Sweden)

    Jeong Hee Kim

    Full Text Available This study describes a sensitive in-cell protease detection system that enables direct fluorescence detection of a target protease and its inhibition inside living cells. This live-cell imaging system provides a fluorescent molecular beacon protein comprised of an intracellular translocation signal sequence, a protease-specific cleavage sequence, and a fluorescent tag sequence(s. The molecular beacon protein is designed to change its intracellular localization upon cleavage by a target protease, i.e., from the cytosol to a subcellular organelle or from a subcellular organelle to the cytosol. Protease activity can be monitored at the single cell level, and accordingly the entire cell population expressing the protease can be accurately enumerated. The clear cellular change in fluorescence pattern makes this system an ideal tool for various life science and drug discovery research, including high throughput and high content screening applications.

  1. Molecular Beacon Based DNA Computing Model for General Satisfiability Problem%可满足问题的分子信标计算模型

    Institute of Scientific and Technical Information of China (English)

    殷志祥; 崔建中; 支凌迎; 孙侠; 黄晓慧

    2008-01-01

    分子信标(Molecular Beacon)是一种发夹状的荧光探针,它可以特异地和那些与分子信标的环(Loop)互补的核酸靶序列杂交,具有单个碱基错配的检测能力.肽核酸(Peptide Nucleic Acid)是人工合成的核酸(DNA)的类似物.PNA骨架为酰胺键,与DNA补链杂交更稳定,可以阻止聚合酶延伸反应.文中将可满足问题的约束变量编码于分子信标的环部识别区,通过分子信标与使得给定范式为真的变量的PNA补链杂交,再利用PNA链可以阻止聚合酶延伸反应的性质,用限制性内切酶EcoRI降解对应于非解的分子信标,最后通过加热表面使分子信标构形发生变化,产生荧光读解.提出的可满足问题的分子信标计算模型具有可靠性高、无需观察和记录计算的中间结果、读解简单等优点.%Molecular Beacon is a hairpin-shaped fluorescent probe,which can hybridize with great specificity target sequence that is complement to its loop sequence.The specificity of Molec-ular Beacon is as high as single base mismatch detection.Peptide Nucleic Acid (PNA) is an artifi-cial synthesized analogue of nature occurring DNA,in which the DNA sugar-phosphate backbone has been replaced by a pseudo-peptide.Thus the hybridization of PNA to complement DNA strand is more specific and stable than that of DNA to DNA.PNA can stop polymerase extension reaction as well.In this paper,Molecular Beacons were employed to encode variables in satisfi-ability problem and complement PNA strands were added and allowed to hybridize with Molecular Beacon.The hybridized PNA strands on Molecular Beacon stopped polymerase extension reac-tion,causing Molecular Beacon corresponding to non-solution were digested by means of restric-tion endonuclease EcoRI.The remaining Molecular Beacons encoding solutions were read out via heating.The appealing characteristics of proposed method in this paper are: Reliable,no obser-vation and record of midst solution,easy solution detection.

  2. Species detection using HyBeacon(®) probe technology: Working towards rapid onsite testing in non-human forensic and food authentication applications.

    Science.gov (United States)

    Dawnay, Nick; Hughes, Rebecca; Court, Denise Syndercombe; Duxbury, Nicola

    2016-01-01

    Identifying individual species or determining species' composition in an unknown sample is important for a variety of forensic applications. Food authentication, monitoring illegal trade in endangered species, forensic entomology, sexual assault case work and counter terrorism are just some of the fields that can require the detection of the biological species present. Traditional laboratory based approaches employ a wide variety of tools and technologies and exploit a number of different species specific traits including morphology, molecular differences and immuno-chemical analyses. A large number of these approaches require laboratory based apparatus and results can take a number of days to be returned to investigating authorities. Having a presumptive test for rapid identification could lead to savings in terms of cost and time and allow sample prioritisation if confirmatory testing in a laboratory is required later. This model study describes the development of an assay using a single HyBeacon(®) probe and melt curve analyses allowing rapid screening and authentication of food products labelled as Atlantic cod (Gadus morhua). Exploiting melt curve detection of species specific SNP sites on the COI gene the test allows detection of a target species (Atlantic cod) and closely related species which may be used as substitutes. The assay has been designed for use with the Field Portable ParaDNA system, a molecular detection platform for non-expert users. The entire process from sampling to result takes approximately 75min. Validation studies were performed on both single source genomic DNA, mixed genomic DNA and commercial samples. Data suggests the assay has a lower limit of detection of 31 pg DNA. The specificity of the assay to Atlantic cod was measured by testing highly processed food samples including frozen, defrosted and cooked fish fillets as well as fish fingers, battered fish fillet and fish pie. Ninety-six (92.7%) of all Atlantic cod food products

  3. Species detection using HyBeacon(®) probe technology: Working towards rapid onsite testing in non-human forensic and food authentication applications.

    Science.gov (United States)

    Dawnay, Nick; Hughes, Rebecca; Court, Denise Syndercombe; Duxbury, Nicola

    2016-01-01

    Identifying individual species or determining species' composition in an unknown sample is important for a variety of forensic applications. Food authentication, monitoring illegal trade in endangered species, forensic entomology, sexual assault case work and counter terrorism are just some of the fields that can require the detection of the biological species present. Traditional laboratory based approaches employ a wide variety of tools and technologies and exploit a number of different species specific traits including morphology, molecular differences and immuno-chemical analyses. A large number of these approaches require laboratory based apparatus and results can take a number of days to be returned to investigating authorities. Having a presumptive test for rapid identification could lead to savings in terms of cost and time and allow sample prioritisation if confirmatory testing in a laboratory is required later. This model study describes the development of an assay using a single HyBeacon(®) probe and melt curve analyses allowing rapid screening and authentication of food products labelled as Atlantic cod (Gadus morhua). Exploiting melt curve detection of species specific SNP sites on the COI gene the test allows detection of a target species (Atlantic cod) and closely related species which may be used as substitutes. The assay has been designed for use with the Field Portable ParaDNA system, a molecular detection platform for non-expert users. The entire process from sampling to result takes approximately 75min. Validation studies were performed on both single source genomic DNA, mixed genomic DNA and commercial samples. Data suggests the assay has a lower limit of detection of 31 pg DNA. The specificity of the assay to Atlantic cod was measured by testing highly processed food samples including frozen, defrosted and cooked fish fillets as well as fish fingers, battered fish fillet and fish pie. Ninety-six (92.7%) of all Atlantic cod food products

  4. An enhanced model of the contemporary and long-term (200 ka) sublimation of the massive subsurface ice in Beacon Valley, Antarctica

    Science.gov (United States)

    Liu, Lu; Sletten, Ronald S.; Hagedorn, Birgit; Hallet, Bernard; McKay, Christopher P.; Stone, John O.

    2015-08-01

    A massive ice body buried under several decimeters of dry regolith in Beacon Valley, Antarctica, is believed to be more than 1 Ma old and perhaps over 8.1 Ma; however, vapor diffusion models suggest that subsurface ice in this region is not stable under current climate conditions. To better understand the controls on sublimation rates and stability of this massive ice, we have modeled vapor diffusion using 12 years of climate and soil temperature data from 1999 to 2011, including field measurements of episodic snow cover and snowmelt events that have not been represented in previous models of ground ice sublimation. The model is then extended to reconstruct the sublimation history over the last 200 ka using paleotemperatures estimated from ice core data from nearby Taylor Dome and a relationship between atmospheric temperature and humidity derived from our meteorological records. The model quantifies the impact of episodic snow events; they account for a nearly 30% reduction in the massive ice loss. The sublimation rate of ground ice averages 0.11 mm a-1 between 1999 and 2011 in Beacon Valley. Parameterized with past environmental conditions and assuming the same regolith thickness, the modeled sublimation rate of ground ice in Beacon Valley averages 0.09 mm a-1 for the last 200 ka, comparable to the long-term average rate estimated independently from various studies based on cosmogenic isotopes. This study provides a realistic estimate of the long-term sublimation history and supports the inference that the buried ice in Beacon Valley is older than 1 Ma.

  5. Molecular beacon based biosensor for the sequence-specific detection of DNA using DNA-capped gold nanoparticles-streptavidin conjugates for signal amplification

    International Nuclear Information System (INIS)

    We describe a highly sensitive and selective molecular beacon-based electrochemical impedance biosensor for the sequence-specific detection of DNA. DNA-capped conjugates between gold nanoparticles (Au-NPs) and streptavidin are used for signal amplification. The molecular beacon was labeled with a thiol at its 5′ end and with biotin at its 3′ end, and then immobilized on the surface of a bare gold electrode through the formation of Au-S bonds. Initially, the molecular beacon is present in the “closed” state, and this shields the biotin from being approached by streptavidin due to steric hindrance. In the presence of the target DNA, the target DNA molecules hybridize with the loop and cause a conformational change that moves the biotin away from the surface of the electrode. The biotin thereby becomes accessible for the reporter (the DNA-streptavidin capped Au-NPs), and this results in a distinct increase in electron transfer resistance. Under optimal conditions, the increase in resistance is linearly related to the logarithm of the concentration of complementary target DNA in the range from 1.0 fM to 0.1 μM, with a detection limit of 0.35 fM (at an S/N of 3). This biosensor exhibits good selectivity, and acceptable stability and reproducibility. (author)

  6. Three-dimensional structure of DNA self-assembly based on molecular beacon%基于分子信标的DNA自组装立体结构

    Institute of Scientific and Technical Information of China (English)

    刘静; 殷志祥

    2014-01-01

    文章讨论了分子信标技术和DNA自组装作为DNA计算的重要模型,并对近年来分子信标技术和DNA自组装技术的发展状况进行了总结;将分子信标技术的优势融入DNA自组装模型,提出一种DNA四面体结构,并利用该结构解决布尔逻辑运算问题。%Molecular beacon and DNA self-assembly as the important DNA computing model are dis-cussed ,and recent developments of molecular beacon technology and DNA self-assembly technology are summarized .The advantages of molecular beacon technology are integrated into DNA self-assem-bly model ,and a tetrahedron structure of DNA is proposed to solve the problem of the Boolean logical operation .

  7. Dual-channel detection of metallothioneins and mercury based on a mercury-mediated aptamer beacon using thymidine-mercury-thymidine complex as a quencher.

    Science.gov (United States)

    Chen, Si-Han; Wang, Yong-Sheng; Chen, Yun-Sheng; Tang, Xian; Cao, Jin-Xiu; Li, Ming-Hui; Wang, Xiao-Feng; Zhu, Yu-Feng; Huang, Yan-Qin

    2015-01-01

    A novel dual-channel strategy for the detection of metallothioneins (MTs) and Hg(2+) has been developed based on a mercury-mediated aptamer beacon (MAB) using thymidine-mercury-thymidine complex as a quencher for the first time. In the presence of Hg(2+), the T-rich oligonucleotide with a 6-carboxyfluorescein (TRO-FAM) can form an aptamer beacon via the formation of T-Hg(2+)-T base pairs, which results in a fluorescence quenching of the sensing system owing to the fluorescence resonance energy transfer (FRET) from the fluorophore of FAM to the terminated T-Hg(2+)-T base pair. The addition of MTs into this solution leads to the disruption of the T-Hg(2+)-T complex, resulting in an increase of the fluorescent signal of the system. In the optimizing condition, ΔF was directly proportional to the concentrations ranging from 5.63 nM to 0.275 μM for MTs, and 14.2 nM to 0.30 μM for Hg(2+) with the detection limits of 1.69 nM and 4.28 nM, respectively. The proposed dual-channel method avoids the label steps of a quencher in common molecular beacon strategies, without tedious procedure or the requirement of sophisticated equipment, and is rapid, inexpensive and sensitive.

  8. Efficacy and safety of QVA149 compared to the concurrent administration of its monocomponents indacaterol and glycopyrronium: the BEACON study

    Directory of Open Access Journals (Sweden)

    Dahl R

    2013-10-01

    Full Text Available Ronald Dahl,1 Dalal Jadayel,2 Vijay KT Alagappan,3 Hungta Chen,3 Donald Banerji31Department of Dermatology, Allergy Centre, Odense University Hospital, Odense, Denmark; 2Novartis Horsham Research Centre, Horsham, UK; 3Novartis Pharmaceuticals Corporation, East Hanover, NJ, USAIntroduction: The BEACON study evaluated the efficacy and safety of QVA149, a once-daily dual bronchodilator containing a fixed-dose combination of the long-acting β2-agonist (LABA indacaterol and long-acting muscarinic antagonist (LAMA glycopyrronium (NVA237, in development for the treatment of patients with chronic obstructive pulmonary disease (COPD, compared with the free-dose concurrent administration of indacaterol plus glycopyrronium (IND+GLY.Methods: In this multicenter, double-blind, parallel group study, patients with stage II or stage III COPD (Global initiative for chronic Obstructive Lung Disease [GOLD] 2010 were randomized (1:1 to once-daily QVA149 (110 µg indacaterol/50 µg glycopyrronium or concurrent administration of indacaterol (150 µg and glycopyrronium (50 µg via the Breezhaler® device (Novartis AG, Basel, Switzerland for 4 weeks. The primary endpoint was to evaluate the noninferiority of QVA149 as compared with concurrent administration of IND+GLY, for trough forced expiratory volume in 1 second (FEV1 after 4 weeks of treatment. The other assessments included FEV1 area under the curve from 0 to 4 hours (AUC0–4 hours at day 1 and week 4, symptom scores, rescue medication use, safety, and tolerability over the 4-week study period.Results: Of 193 patients randomized, 187 (96.9% completed the study. Trough FEV1 at week 4 for QVA149 and IND+GLY was 1.46 L ± 0.02 and 1.46 L ± 0.18, respectively. The FEV1 AUC0–4 hours at day 1 and week 4 were similar between the two treatment groups. Both treatment groups had a similar reduction in symptom scores and rescue medication use for the 4-week treatment period. Overall, 25.6% of patients in QVA149 group

  9. Monitoring p21 mRNA expression in living cell based on molecular beacon fluorescence increasing rate

    Institute of Scientific and Technical Information of China (English)

    TANG HongXing; YANG XiaoHai; WANG KeMin; TAN WeiHong; LIU Bin; HE LiFang; WANG Wei

    2008-01-01

    Studying the expression level of mRNA in living cells will offer tremendous opportunities for ad-vancement in cell biology research, disease diagnostics, and drug discovery. In this paper, a molecular beacon (MB) specific for the important tumor suppressor gene p21 has been designed and synthesized. The fluorescence signal was detected in real-time after the MB entered the cytoplasm of nasopharyn-geal carcinoma cells. After injecting the p21MB into nasopharyngeal carcinoma cell and p33-trans-fected nasopharyngeal carcinoma cell, the consistent increase of fluorescent signal intensity was de-tected in both cell lines, and maximum fluorescence intensity achieved in about 15 min. In about 4 min following microinjection, the fluorescence increasing rate was significantly different between these two cell lines, which indicate the different p21 mRNA expression levels. The results obtained in the real-time detection were also validated by RT-PCR. Analysis of the initial fluorescence increasing rate can effi-ciently reduce the side effect of enzyme and improve the accuracy in living cell mRNA detection.

  10. Comparison of mapped and measured total ionospheric electron content using global positioning system and beacon satellite observations

    International Nuclear Information System (INIS)

    Total ionospheric electron contents (TEC) were measured by global positioning system (GPS) dual-frequency receivers developed by the Jet Propulsion Laboratory. The measurements included P-code (precise ranging code) and carrier phase data for six GPS satellites during multiple five-hour observing sessions. A set of these GPS TEC measurements were mapped from the GPS lines of sight to the line of sight of a Faraday beacon satellite by statistically fitting the TEC data to a simple model of the ionosphere. The mapped GPS TEC values were compared with the Faraday rotation measurements. Because GPS transmitter offsets are different for each satellite and because some GPS receiver offsets were uncalibrated, the sums of the satellite and receiver offsets were estimated simultaneously with the TEC in a least squares procedure. The accuracy of this estimation procedure is evaluated indicating that the error of the GPS-determined line of sight TEC can be at or below 1 x 10 to the 16th el/sq cm. Consequently, the current level of accuracy is comparable to the Faraday rotation technique; however, GPS provides superior sky coverage. 15 references

  11. Expression patterns of prion protein gene in differential genotypes sheep: quantification using molecular beacon real-time RT-PCR.

    Science.gov (United States)

    Wang, Chuan; Wu, Run; Li, Fa-Di; Liu, Lei; Zhang, Xiao-Li; Zhao, Chun-Lin; Diao, Xiao-Long; Guan, Hong-Wei

    2011-06-01

    Determination of the transcription level of cellular prion protein (PrP(C)) is essential for understanding its role in organisms and revealing mechanism of susceptibility and resistance to scrapie. However, the expression of prion protein (PrP) mRNA in sheep has not been quantified in great detail in digestive tract which is important during scrapie spread through oral route. Herein, we report on measurement of sheep PrP mRNA using absolute quantitative real-time RT-PCR. Total RNA was isolated from five different regions of the central nervous system (CNS), four regions of lymphoid system, eleven regions of digestive tract, and two reproductive organ tissues of eight sheep of two different genotypes (ARR/ARQ and ARH/ARQ) and PrP mRNA was quantified by real-time RT-PCR using molecular beacon. The results showed that highest levels of PrP mRNA were expressed in thalamus and cerebrum (P mRNA expression in sheep for further studies of pathogenesis of prion diseases.

  12. Dual hairpin-like molecular beacon based on coralyne-adenosine interaction for sensing melamine in dairy products.

    Science.gov (United States)

    Wang, Guangfeng; Zhu, Yanhong; Chen, Ling; Zhang, Xiaojun

    2014-11-01

    This study presents a novel dual hairpin-like molecular beacon (MB) for the selective and sensitive detection of melamine (MA) based on the conjugation of MA and thymine. In this protocol, the coordination between coralyne and adenosine (A) leaded a dual hairpin-like MB and the fluorophore-quencher pair is close proximity resulting in the fluorescence quenching. With the addition of MA, it conjugated with thymine in the loop part of dual hairpin-like MB by triple H-bonds, triggering the dissociation of the dual hairpin-like MB. The resulting spatial separation of the fluorophore from quencher induced the enhancement in fluorescence emission. Under the optimized conditions, the sensor exhibited a wide linear range of 8×10(-9)-1.6×10(-5) M (R(2)=0.9969) towards MA, with a low detection limit of 5 nM, approximately 4000 times lower than the Drug Administration and the US Food estimated MA safety limit. The real milk samples were also investigated with a satisfying result.

  13. A label-free fluorescent molecular beacon based on DNA-Ag nanoclusters for the construction of versatile Biosensors.

    Science.gov (United States)

    Cao, Qiao; Teng, Ye; Yang, Xuan; Wang, Jin; Wang, Erkang

    2015-12-15

    In this paper, we developed a simple, low-cost and sensitive DNA sequences detection biosensor based on a label-free molecular beacon (MB) whose DNA hairpin structure terminal has a guanine-rich sequence that can enhance fluorescence of silver nanoclusters (Ag NCs). Without hybridization between hairpin probe and target DNA, the Ag NCs presented bright fluorescence for the proximity of guanine-rich sequences (GRSs). After binding with target DNA, the hairpin shape was destroyed which results in a decrease of the Ag NCs fluorescence intensity. With this biosensor, we detected three disease-related genes that were the human immunodeficiency virus (HIV) gene, hepatitis B virus (HBV) gene and human T-lymphotropic virus type I (HTLV-I) gene. The detection limits based on S/N of 3 were 4.4 nM, 6.8 nM and 8.5 nM for HIV gene, HBV gene and HTLV-I gene, respectively. Our sensor was also of high selectivity and could distinguish even one nucleotide mismatched target.

  14. 三光源 LED 光信标空间布局优化计算%Calculation on the Layout of A LED Optical Beacon with Three Sources

    Institute of Scientific and Technical Information of China (English)

    王彩玲

    2015-01-01

    在航空、海运及海上救生等各方面,光学信标是一种重要的光学指示手段。为了适应较远作用距离的要求,提出了采用高亮度、高发光效率的LED光源的光学信标。针对采用三光源光信标的空间布局进行了相关理论计算,建立光束空间数学模型,给出三光源的最佳空间布置,并计算出光信标盲区范围及盲区大小。本文的计算结果为光信标的结构设计提供必要的理论基础,其计算方法为多光源信标空间布局计算提供一定的参考。%The optical beacon is an important position indicator in aviation , sea transportation and the sea life saving .With the need of the remote indication , the optical beacon with LED sources , owing to high brightness and luminous efficiency , is presented .Based on the established mathematical model of the light beam , the layout of the beacon with three lamp-houses is calculated theoretically , and the optimal layout , the ranges and the sizes of the blind zenos of the beacon are discussed .The results provide a theoretical guide for the structure design of the beacon essentially , and the method can be referred to layout of other multi-sources beacon .

  15. Calculation on the Layout of A LED Optical Beacon with Three Sources%三光源 LED 光信标空间布局优化计算

    Institute of Scientific and Technical Information of China (English)

    王彩玲

    2015-01-01

    The optical beacon is an important position indicator in aviation , sea transportation and the sea life saving .With the need of the remote indication , the optical beacon with LED sources , owing to high brightness and luminous efficiency , is presented .Based on the established mathematical model of the light beam , the layout of the beacon with three lamp-houses is calculated theoretically , and the optimal layout , the ranges and the sizes of the blind zenos of the beacon are discussed .The results provide a theoretical guide for the structure design of the beacon essentially , and the method can be referred to layout of other multi-sources beacon .%在航空、海运及海上救生等各方面,光学信标是一种重要的光学指示手段。为了适应较远作用距离的要求,提出了采用高亮度、高发光效率的LED光源的光学信标。针对采用三光源光信标的空间布局进行了相关理论计算,建立光束空间数学模型,给出三光源的最佳空间布置,并计算出光信标盲区范围及盲区大小。本文的计算结果为光信标的结构设计提供必要的理论基础,其计算方法为多光源信标空间布局计算提供一定的参考。

  16. Method of Soldier Localization in Battlefield Based on Mobile Beacon in Unmanned Aerial Vehicle%一种基于无人机移动信标的战场士兵定位方法的研究

    Institute of Scientific and Technical Information of China (English)

    高丹丹; 吴宝明; 王圣超; 苏清章

    2012-01-01

    目的:以战场士兵搜索为背景,研究一种新的基于无人机移动信标的战场士兵定位方法.方法:无人机沿“∞”模型飞行,机载信标获取相对地理位置信息,并且周期性地发送唤醒信号;士兵节点被唤醒后,发送RSSI数据包,再次进入休眠状态;移动信标接收士兵节点RSSI数据包,在接收位置形成该节点对应的虚拟信标;计算士兵节点到所对应的虚拟信标的距离矩阵,从而进一步计算士兵节点的相对地理坐标.结果:仿真测试随机布设20个结构相同的士兵节点,当平均每个士兵节点对应的虚拟信标数为8.3个时,平均定位误差为7.78%.结论:基于无人机移动信标的定位方法具有较高的定位精度,有望用于战场士兵定位.%Objective To develop a new method of localization based on mobile beacon for searching and rescuing of the wounded in battlefield. Methods When the unmanned aerial vehicle (UAV) was flying along the model "∞", the beacon in the vehicle got the relative location information, and sent the periodic wake-up signals. When receiving the wake-up signals, the unknown position soldiers sent RSSI, and fell asleep again. Beacon collected the RSSI and formed a corresponding virtual beacon. Beacon calculated the distance between the unknown node and the corresponding virtual beacons, and calculated node relative location, which would be sent to the rear headquarters. Results In simulation, 20 soldier nodes with same style were laid randomly. When the average virtual beacon per 1 soldier was 8.3, the average localization error was 7.78%. Conclusion The proposed localization method based on mobile beacon in UAV possesses a better location accuracy, which is expected for battlefield soldier location.[Chinese Medical Equipment Journal,2012,33 (4)r4-6

  17. Novel Molecular Beacon Probe-Based Real-Time RT-PCR Assay for Diagnosis of Crimean-Congo Hemorrhagic Fever Encountered in India

    Directory of Open Access Journals (Sweden)

    Aman Kamboj

    2014-01-01

    Full Text Available Crimean-Congo hemorrhagic fever (CCHF is an emerging zoonotic disease in India and requires immediate detection of infection both for preventing further transmission and for controlling the infection. The present study describes development, optimization, and evaluation of a novel molecular beacon-based real-time RT-PCR assay for rapid, sensitive, and specific diagnosis of Crimean-Congo hemorrhagic fever virus (CCHFV. The developed assay was found to be a better alternative to the reported TaqMan assay for routine diagnosis of CCHF.

  18. An ultrasensitive alloyed near-infrared quinternary quantum dot-molecular beacon nanodiagnostic bioprobe for influenza virus RNA.

    Science.gov (United States)

    Adegoke, Oluwasesan; Kato, Tatsuya; Park, Enoch Y

    2016-06-15

    Conventional techniques used to diagnose influenza virus face several challenges, such as low sensitivity, slow detection, false positive results and misinterpreted data. Hence, diagnostic probes that can offer robust detection qualities, such as high sensitivity, rapid detection, elimination of false positive data, and specificity for influenza virus, are urgently needed. The near-infrared (NIR) range is an attractive spectral window due to low photon absorption by biological tissues, hence well-constructed fluorescent biosensors that emit within the NIR window can offer an improved limit of detection (LOD). Here, we demonstrate the use of a newly synthesized NIR quinternary alloyed CdZnSeTeS quantum dots (QDs) as an ultrasensitive fluorescence reporter in a conjugated molecular beacon (MB) assay to detect extremely low concentrations of influenza virus H1N1 RNA. Under optimum conditions, two different strains of influenza virus H1N1 RNA were detected based on fluorescence enhancement signal transduction. We successfully discriminated between two different strains of influenza virus H1N1 RNA based on the number of complementary nucleotide base pairs of the MB to the target RNA sequence. The merits of our bioprobe system are rapid detection, high sensitivity (detects H1N1 viral RNA down to 2 copies/mL), specificity and versatility (detects H1N1 viral RNA in human serum). For comparison, a conventional CdSe/ZnS-MB probe could not detect the extremely low concentrations of H1N1 viral RNA detected by our NIR alloyed CdZnSeTeS-MB probe. Our bioprobe detection system produced a LOD as low as ~1 copy/mL and is more sensitive than conventional molecular tests and rapid influenza detection tests (RIDTS) probes.

  19. An ultrasensitive alloyed near-infrared quinternary quantum dot-molecular beacon nanodiagnostic bioprobe for influenza virus RNA.

    Science.gov (United States)

    Adegoke, Oluwasesan; Kato, Tatsuya; Park, Enoch Y

    2016-06-15

    Conventional techniques used to diagnose influenza virus face several challenges, such as low sensitivity, slow detection, false positive results and misinterpreted data. Hence, diagnostic probes that can offer robust detection qualities, such as high sensitivity, rapid detection, elimination of false positive data, and specificity for influenza virus, are urgently needed. The near-infrared (NIR) range is an attractive spectral window due to low photon absorption by biological tissues, hence well-constructed fluorescent biosensors that emit within the NIR window can offer an improved limit of detection (LOD). Here, we demonstrate the use of a newly synthesized NIR quinternary alloyed CdZnSeTeS quantum dots (QDs) as an ultrasensitive fluorescence reporter in a conjugated molecular beacon (MB) assay to detect extremely low concentrations of influenza virus H1N1 RNA. Under optimum conditions, two different strains of influenza virus H1N1 RNA were detected based on fluorescence enhancement signal transduction. We successfully discriminated between two different strains of influenza virus H1N1 RNA based on the number of complementary nucleotide base pairs of the MB to the target RNA sequence. The merits of our bioprobe system are rapid detection, high sensitivity (detects H1N1 viral RNA down to 2 copies/mL), specificity and versatility (detects H1N1 viral RNA in human serum). For comparison, a conventional CdSe/ZnS-MB probe could not detect the extremely low concentrations of H1N1 viral RNA detected by our NIR alloyed CdZnSeTeS-MB probe. Our bioprobe detection system produced a LOD as low as ~1 copy/mL and is more sensitive than conventional molecular tests and rapid influenza detection tests (RIDTS) probes. PMID:26890823

  20. Age-specific risk factor profiles of adenocarcinomas of the esophagus: A pooled analysis from the international BEACON consortium.

    Science.gov (United States)

    Drahos, Jennifer; Xiao, Qian; Risch, Harvey A; Freedman, Neal D; Abnet, Christian C; Anderson, Lesley A; Bernstein, Leslie; Brown, Linda; Chow, Wong-Ho; Gammon, Marilie D; Kamangar, Farin; Liao, Linda M; Murray, Liam J; Ward, Mary H; Ye, Weimin; Wu, Anna H; Vaughan, Thomas L; Whiteman, David C; Cook, Michael B

    2016-01-01

    Esophageal (EA) and esophagogastric junction (EGJA) adenocarcinoma have been steadily increasing in frequency in younger people; however, the etiology of these cancers is poorly understood. We therefore investigated associations of body mass index (BMI), cigarette smoking, alcohol consumption, gastroesophageal reflux and use of nonsteroidal anti-inflammatory drugs (NSAIDs) in relation to age-specific risks of EA and EGJA. We pooled individual participant data from eight population-based, case-control studies within the international Barrett's and Esophageal Adenocarcinoma Consortium (BEACON). The analysis included 1,363 EA patients, 1,472 EGJA patients and 5,728 control participants. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for age-specific (<50, 50-59, 60-69, ≥70 years) cancer outcomes, as well as interactions by age. BMI, smoking status and pack-years, recurrent gastroesophageal reflux and frequency of gastroesophageal reflux were positively associated with EA and EGJA in each age group. Early-onset EA (<50 years) had stronger associations with recurrent gastroesophageal reflux (OR = 8.06, 95% CI: 4.52, 14.37; peffect modification  = 0.01) and BMI (ORBMI ≥ 30 vs . <25  = 4.19, 95% CI: 2.23, 7.87; peffect modification  = 0.04), relative to older age groups. In contrast, inverse associations of NSAID use were strongest in the oldest age group (≥70 years), although this apparent difference was not statistically significant. Age-specific associations with EGJA showed similar, but slightly weaker patterns and no statistically significant differences by age were observed. Our study provides evidence that associations between obesity and gastroesophageal reflux are stronger among earlier onset EA cancers.

  1. Age-specific risk factor profiles of adenocarcinomas of the esophagus: A pooled analysis from the international BEACON consortium.

    Science.gov (United States)

    Drahos, Jennifer; Xiao, Qian; Risch, Harvey A; Freedman, Neal D; Abnet, Christian C; Anderson, Lesley A; Bernstein, Leslie; Brown, Linda; Chow, Wong-Ho; Gammon, Marilie D; Kamangar, Farin; Liao, Linda M; Murray, Liam J; Ward, Mary H; Ye, Weimin; Wu, Anna H; Vaughan, Thomas L; Whiteman, David C; Cook, Michael B

    2016-01-01

    Esophageal (EA) and esophagogastric junction (EGJA) adenocarcinoma have been steadily increasing in frequency in younger people; however, the etiology of these cancers is poorly understood. We therefore investigated associations of body mass index (BMI), cigarette smoking, alcohol consumption, gastroesophageal reflux and use of nonsteroidal anti-inflammatory drugs (NSAIDs) in relation to age-specific risks of EA and EGJA. We pooled individual participant data from eight population-based, case-control studies within the international Barrett's and Esophageal Adenocarcinoma Consortium (BEACON). The analysis included 1,363 EA patients, 1,472 EGJA patients and 5,728 control participants. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for age-specific (<50, 50-59, 60-69, ≥70 years) cancer outcomes, as well as interactions by age. BMI, smoking status and pack-years, recurrent gastroesophageal reflux and frequency of gastroesophageal reflux were positively associated with EA and EGJA in each age group. Early-onset EA (<50 years) had stronger associations with recurrent gastroesophageal reflux (OR = 8.06, 95% CI: 4.52, 14.37; peffect modification  = 0.01) and BMI (ORBMI ≥ 30 vs . <25  = 4.19, 95% CI: 2.23, 7.87; peffect modification  = 0.04), relative to older age groups. In contrast, inverse associations of NSAID use were strongest in the oldest age group (≥70 years), although this apparent difference was not statistically significant. Age-specific associations with EGJA showed similar, but slightly weaker patterns and no statistically significant differences by age were observed. Our study provides evidence that associations between obesity and gastroesophageal reflux are stronger among earlier onset EA cancers. PMID:26175109

  2. Mapping plasma structures in the high-latitude ionosphere using beacon satellite, incoherent scatter radar and ground-based magnetometer observations

    Directory of Open Access Journals (Sweden)

    T. Neubert

    2002-06-01

    Full Text Available In the autumn of the year 2000, four radio receivers capable of tracking various beacon satellites were set up along the southwestern coast of Greenland. They are used to reconstruct images of the ionospheric plasma density distribution via the tomographic method. In order to test and validate tomographic imaging under the highly variable conditions often prevailing in the high-latitude ionosphere, a time interval was selected when the Sondrestrom incoherent scatter radar conducted measurements of the ionospheric plasma density while the radio receivers tracked a number of beacon satellites. A comparison between two-dimensional images of the plasma density distribution obtained from the radar and the satellite receivers revealed generally good agreement between radar measurements and tomographic images. Observed discrepancies can be attributed to F region plasma patches moving through the field of view with a speed of several hundred meters per second, thereby smearing out the tomographic image. A notable mismatch occurred around local magnetic midnight when a magnetospheric substorm breakup occurred in the vicinity of southwest Greenland (identified from ground-based magnetometer observations. The breakup was associated with a sudden intensification of the westward auroral electrojet which was centered at about 69 and extended up to some 73 corrected geomagnetic latitude. Ground-based magnetometer data may thus have the potential of indicating when the tomographic method is at risk and may fail. We finally outline the application of tomographic imaging, when combined with magnetic field data, to estimate ionospheric Joule heating rates.

  3. Metody určování polohy v uzavřených prostorách prostřednictvím technologie iBeacon

    OpenAIRE

    Snopek, Jan

    2015-01-01

    This thesis compares indoor location methods with emphasis on iBeacon technology and its potential. In the review part of the thesis, basic technological properties are outlined. Further, a concept of application for indoor location is proposed. Finally, a set of experiments is described and the results are evaluated.

  4. Evaluation of a molecular beacon real-time PCR assay for detection of Baylisascaris procyonis in different soil types and water samples.

    Science.gov (United States)

    Gatcombe, Rachel R; Jothikumar, Narayanan; Dangoudoubiyam, Sriveny; Kazacos, Kevin R; Hill, Vincent R

    2010-01-01

    Baylisascaris procyonis is a helminth parasite commonly found in North American raccoons (Procyon lotor) that is a cause of clinical neural, ocular, and visceral larva migrans in humans when infective eggs are ingested. Rapid detection of B. procyonis eggs in contaminated soil and water would assist public health analysts in evaluating risks associated with public exposure to areas of known raccoon activity. In this study, a molecular beacon probe-based real-time polymerase chain reaction (PCR) assay was developed to enable rapid and specific detection of eggs of Baylisascaris spp. The molecular beacon assay targeted the cytochrome oxidase subunit 2 (cox-2) gene of B. procyonis. To determine method sensitivity, experiments testing various egg levels (250, 25, and five eggs) were performed by seeding into 0.5-g soil samples or 0.5-mL water samples. Different soil sample types were extracted using a commercial nucleic acid extraction kit. Specificity testing using previously characterized helminth tissue specimens indicated that the assay was specific to Baylisascaris spp. Little real-time PCR inhibition was observed for most of the soil and water samples. A seed level of 250 eggs was detected for all soil types, and two seed levels (25 and five eggs) were detected for surface water samples. These results demonstrate that the reported real-time PCR assay was effective for the sensitive detection of B. procyonis in a wide range of soil types, and should be a useful tool for investigations of soil or water potentially contaminated with eggs of this parasite.

  5. Ligation-rolling circle amplification combined with γ-cyclodextrin mediated stemless molecular beacon for sensitive and specific genotyping of single-nucleotide polymorphism.

    Science.gov (United States)

    Zou, Zhen; Qing, Zhihe; He, Xiaoxiao; Wang, Kemin; He, Dinggeng; Shi, Hui; Yang, Xue; Qing, Taiping; Yang, Xiaoxiao

    2014-07-01

    A novel approach for highly sensitive and selective genotyping of single-nucleotide polymorphism (SNP) has been developed based on ligation-rolling circle amplification (L-RCA) and stemless molecular beacon. In this approach, two tailored DNA probes were involved. The stemless molecular beacon, formed through the inclusion interactions of γ-cyclodextrin (γ-CD) and bis-pyrene labeled DNA fragment, was served as signal probe. In the absence of mutant target, the two pyrene molecules were bound in the γ-CD cavity to form an excimer and showed a strong fluorescence at 475 nm. It was here named γ-CD-P-MB. The padlock DNA probe was designed as recognition probe. Upon the recognition of a point mutation DNA targets, the padlock probe was ligated to generate a circular template. An RCA amplification was then initiated using the circular template in the presence of Phi29 polymerase and dNTPs. The L-RCA products, containing repetitive sequence units, subsequently hybridized with the γ-CD-P-MB. This made pyrene molecules away from γ-CD cavity and caused a decrease of excimer fluorescence. As a proof-of-concept, SNP typing of β-thalassemia gene at position -28 was investigated using this approach. The detection limit of mutated target was determined to be 40 fM. In addition, DNA ligase offered high fidelity in distinguishing the mismatched bases at the ligation site, resulting in positive detection of mutant target even when the ratio of the wildtype to the mutant is 999:1. Given these attractive characteristics, the developed approach might provide a great genotyping platform for pathogenic diagnosis and genetic analysis.

  6. Highly sensitive detection of cancer-related genes based on complete fluorescence restoration of a molecular beacon with a functional overhang.

    Science.gov (United States)

    Li, Feng; Zhou, Ying-Ying; Peng, Ting; Xu, Huo; Zhang, Rong-Bo; Zhao, Hui; Wang, Zheng-Yong; Lv, Jian-Xin; Wu, Zai-Sheng; Shen, Zhi-Fa

    2016-07-21

    The accurate detection of cancer-related genes is of great significance for early diagnosis and targeted therapy of cancer. In this contribution, an automatically cycling operation of a functional overhang-containing molecular beacon (OMB)-based sensing system was proposed to perform amplification detection of the p53 gene. Contrary to the common molecular beacon (MB), a target DNA is designated to hybridize with a label-free recognition probe (RP) with a hairpin structure rather than OMB. In the presence of a target DNA of interest, the locked primer in RP opens and triggers the subsequent amplification procedures. The newly-developed OMB is not only capable of accomplishing cyclical nucleic acid strand-displacement polymerization (CNDP) with the help of polymerase and nicking endonuclease, but is also cleaved by restriction endonucleases, removing the quencher away from the fluorophore. Thus, the target DNA at an extremely low concentration is expected to generate a considerable amount of double-stranded and cleaved OMBs, and the quenched fluorescence is completely restored, leading to a dramatic increase in fluorescence intensity. Utilizing this sensing platform, the target gene can be detected down to 8.2 pM in a homogeneous way, and a linear response range of 0.01 to 150 nM could be obtained. More strikingly, the mutant genes can be easily distinguished from the wild-type ones. The proof-of-concept demonstrations reported herein are expected to promote the development of DNA biosensing systems, showing great potential in basic research and clinical diagnosis.

  7. Highly sensitive detection of cancer-related genes based on complete fluorescence restoration of a molecular beacon with a functional overhang.

    Science.gov (United States)

    Li, Feng; Zhou, Ying-Ying; Peng, Ting; Xu, Huo; Zhang, Rong-Bo; Zhao, Hui; Wang, Zheng-Yong; Lv, Jian-Xin; Wu, Zai-Sheng; Shen, Zhi-Fa

    2016-07-21

    The accurate detection of cancer-related genes is of great significance for early diagnosis and targeted therapy of cancer. In this contribution, an automatically cycling operation of a functional overhang-containing molecular beacon (OMB)-based sensing system was proposed to perform amplification detection of the p53 gene. Contrary to the common molecular beacon (MB), a target DNA is designated to hybridize with a label-free recognition probe (RP) with a hairpin structure rather than OMB. In the presence of a target DNA of interest, the locked primer in RP opens and triggers the subsequent amplification procedures. The newly-developed OMB is not only capable of accomplishing cyclical nucleic acid strand-displacement polymerization (CNDP) with the help of polymerase and nicking endonuclease, but is also cleaved by restriction endonucleases, removing the quencher away from the fluorophore. Thus, the target DNA at an extremely low concentration is expected to generate a considerable amount of double-stranded and cleaved OMBs, and the quenched fluorescence is completely restored, leading to a dramatic increase in fluorescence intensity. Utilizing this sensing platform, the target gene can be detected down to 8.2 pM in a homogeneous way, and a linear response range of 0.01 to 150 nM could be obtained. More strikingly, the mutant genes can be easily distinguished from the wild-type ones. The proof-of-concept demonstrations reported herein are expected to promote the development of DNA biosensing systems, showing great potential in basic research and clinical diagnosis. PMID:27221763

  8. Opportunistic beacon networks

    NARCIS (Netherlands)

    Türkes, Okan

    2016-01-01

    Modern society is surrounded by an ample spectrum of personal mobile devices with short-range wireless communication support. This ubiquity creates an immense potential of new concepts for people-centric ad hoc networks that can be applied to every personal and social dimension of life. The last dec

  9. Beacon of Development

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Premier Wen Jiabao sends crucial signals to the international community at UN headquarters For the first time since he took office five years ago, Chinese Premier Wen Jiabao addressed the United Nations in New York on September

  10. Lateral Beacons - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  11. Improving DV-Hop Localisation Algorithm Based on Mobile Beacon for WSNs%传感器网络基于移动信标改进的DV-Hop定位算法

    Institute of Scientific and Technical Information of China (English)

    谢晓松; 程良伦

    2011-01-01

    无线传感器网络节点定位算法的精度多依赖于信标节点的密度,但信标节点成本高,约为普通节点的100倍以上,为了降低定位的成本,提出了一种基于移动信标和DV-Hop的无线传感器网络节点定位算法(MBWDV-Hop).该算法在DV-Hop定位算法的基础上,利用一个移动的信标节点在网络中按预定的路径移动并不断地广播自己的位置信息,形成多个虚拟信标,未知节点记录到每个虚拟信标的跳数,并采用加权处理的方法计算平均跳距及其与各虚拟信标的距离,最后利用三边测量法计算未知节点的位置信息,实现节点精确定位.由于只采用一个移动信标,降低了定位的成本和布网的复杂度.最后通过仿真证明算法可以提高定位精度,降低定位成本,提高了定位的效率.%The precision of localisation algorithm for wireless sensor networks mostly relies on the density of beacon node, but the beacon node is very expensive, approximately more than 100 times of the ordinary node. In order to curtail the cost of localisation, we propose a kind of WSN localisation algorithm based on mobile beacon and DV-Hop (MBWDV-Hop). In this algorithm, on the basis of DV-Hop localisation algorithm, a mobile beacon node is used to move around the network according to destined path and to broadcast continually the messages with regard to its own localisation, and this forms a lot of virtual beacons in network. The unknown node records the number of hops from each virtual beacon and uses weighedprocessing method to calculate the average of one-hop distance and the distances between it itself and each virtual beacon. At the end, trilateration method is used to calculate the position information of the unknown node to achieve accurate localisation of the node. Since only one mobile beacon is used in this algorithm, the cost of localisation and the complexity of network deployment can be reduced. Simulation result demonstrates that

  12. 基于锚同心圆的改进加权质心WSN定位算法%An Improved Weighted Centroid Localization Algorithm Based on Concentric Anchor- Beacons for Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    李尧尧; 廖红云; 曾孝平; 吴小林

    2011-01-01

    Concentric anchor beacons (CAB) localization algorithm is a range -free wireless sensor networks localization algorithm. Comparing with the traditional range localization algorithm, although it can reduce the nodes energy consumption, the localization accuracy is no better than traditional range localization approaches. In order to further improve the accuracy of localizing nodes, an improved weighted centroid algorithm based on CAB is proposed after analyzing the radio propagation path loss. First, the process of this improved algorithm is introduced. Then, the influence of communication radius on the accuracy of this new localization algorithm was simulated. After that, the accuracy of this localization algorithm were compared with the existing several kinds of range - free localization methods. Simulation results show that this new algorithm has a higher positioning accuracy and not sensitive to communication radius, and it has some value in productive practice.%研究无线传感器定位准确性问题,针对测量位置节点信息,为了提高无线传感器网络的定位精度,采用同心圆定位算法(CAB)是一种免测距的无线传感器定位算法,相比于传统的测距方法能降低节点的能量消耗,但是定位精度却不及传统的测距定位方法.提出在同心圆定位算法(CAB)的基础上,通过分析无线电传播路径损耗采用了一种加权同心圆定位算法.给出了算法的流程,仿真分析了通信半径对新算法定位精度的影响,比较了算法定位精度与现有的几种免测距定位方法的定位精度.仿真结果表明,改进算法有较高的定位精度而且对距离不敏感,对实际工程提供应用价值.

  13. Correcting Localization Error with a Single Beacon for AUV%一种利用单信标修正AUV定位误差的方法

    Institute of Scientific and Technical Information of China (English)

    张福斌; 张永清

    2012-01-01

    The localization error of an AUV's integrated navigation positioning system, which is composed of strapdown inertial navigation system (SINS), Doppler velocity logger (DVL) and depth sensor, increases with time, and the hidden performance of the AUV will decrease in correcting the error via GPS. In this paper, a new method is proposed to correct the localization error of the AUV's navigation system by adopting a fixed beacon under water. In this method, the principle of acoustic ranging is used to measure the distance between AUV and beacon, then the real-time position of the AUV is calculated according to spacial geometric relationships, and the localization error of the AUV's navigation system is corrected by Kalman filter. Simulation results show that the present approach can correct AUV's localization error effectively, which infers an application value in engineering.%针对配置有捷联惯导(SINS)/多普勒速度仪(DVL)/深度传感器组合导航定位系统的自主水下航行器(AUV)的定位误差随时间增大,以及采用GPS修正定位误差引起的AUV隐蔽性降低等问题,提出了一种利用水下固定单信标修正SINS/DVL/深度传感器组合定位误差的方法.该方法首先利用水声测距原理测量出AUV与水下固定单信标的距离,然后基于空间几何关系计算出AUV的实时位置,最后通过卡尔曼滤波连续修正AUV的定位误差.仿真结果表明,该方法可以有效减小AUV的定位误差,有较好的工程应用价值.

  14. Molecular Beacon Enables Combination of Highly Processive and Highly Sensitive Rolling Circle Amplification Readouts for Detection of DNA-Modifying Enzymes

    DEFF Research Database (Denmark)

    Kristoffersen, Emil Laust; Gonzales, Maria; Stougaard, Magnus;

    2015-01-01

    Here we present an optimized readout format for detection of the circularized products from a DNA-based sensor for measurement of DNA-modifying enzymes including DNA Topoisomerase I. The basic design of the DNA-sensor relies on the use of a substrate that can be circularized by the activity of DN...

  15. Molecular beacon-based real-time PCR detection of primary isolates of Salmonella Typhimurium and Salmonella Enteritidis in environmental and clinical samples

    Directory of Open Access Journals (Sweden)

    Emmanuel Maria A

    2009-05-01

    Full Text Available Abstract Background A fast and simple two-step multiplex real-time PCR assay has been developed to replace the traditional, laborious Salmonella serotyping procedure. Molecular beacons were incorporated into the assay as probes for target DNA. Target sequences were regions of the invA, prot6E and fliC genes specific for Salmonella spp. Salmonella Enteritidis and Salmonella Typhimurium, respectively, the two most clinically relevant serotypes. An internal amplification positive control was included in the experiment to ensure the optimal functioning of the PCR and detect possible PCR inhibition. Three sets of primers were used for the amplification of the target sequences. The results were compared to those of the Kauffmann-White antigenic classification scheme. Results The assay was 100% sensitive and specific, correctly identifying all 44 Salmonella strains, all 21 samples of S. Enteritidis and all 17 samples of S. Typhimurium tested in this work. Therefore, the entire experiment had specificity and sensitivity of 100%. The detection limit was down to 10 copies of DNA target per 25 μl reaction. Conclusion The assay can amplify and analyse a large number of samples in approximately 8 hours, compared to the 4 to 5 days conventional identification takes, and is thus considered a very promising method for detecting the two major serotypes of Salmonella quickly and accurately from clinical and environmental samples.

  16. Single-molecule detection and tracking of RNA transcripts in living cells using phosphorothioate-optimized 2'-O-methyl RNA molecular beacons.

    Science.gov (United States)

    Zhao, Dan; Yang, Yantao; Qu, Na; Chen, Mingming; Ma, Zhao; Krueger, Christopher J; Behlke, Mark A; Chen, Antony K

    2016-09-01

    Molecular Beacons (MBs) composed of 2'-O-methyl RNA (2Me) and phosphorothioate (PS) linkages throughout the backbone (2Me/PSFULL MBs) have enabled long-term imaging of RNA in living cells, but excess PS modification can induce nonspecific binding, causing false-positive signals. In this study, we evaluate the intracellular stability of MBs composed of 2Me with various PS modifications, and found that false-positive signals could be reduced to marginal levels when the MBs possess a fully PS-modified loop domain and a phosphodiester stem (2Me/PSLOOP MB). Additionally, 2Me/PSLOOP MBs exhibited uncompromised hybridization kinetics, prolonged functionality and >88% detection accuracy for single RNA transcripts, and could do so without interfering with gene expression or cell growth. Finally, 2Me/PSLOOP MBs could image the dynamics of single mRNA transcripts in the nucleus and the cytoplasm simultaneously, regardless of whether the MBs targeted the 5'- or the 3'-UTR. Together, these findings demonstrate the effectiveness of loop-domain PS modification in reducing nonspecific signals and the potential for sensitive and accurate imaging of individual RNAs at the single-molecule level. With the growing interest in the role of RNA localization and dynamics in health and disease, 2Me/PSLOOP MBs could enable new discoveries in RNA research. PMID:27261815

  17. Calculation and analysis of the number of return photons from sodium laser beacon excited by the long pulse laser with circular polarization

    International Nuclear Information System (INIS)

    The number of return photons from sodium laser beacon (SLB) greatly suffers down-pumping, recoil, and geomagnetic field when the long pulse laser with circular polarization interacts with sodium atoms in the mesosphere. Considering recoil and down-pumping effects on the number of return photons from SLB, the spontaneous radiation rates are obtained by numerical computations and fittings. Furthermore, combining with the geomagnetic field effects, a new expression is achieved for calculating the number of return photons. By using this expression and considering the stochastic distribution of laser intensity in the mesosphere under different turbulence models for atmosphere, the number of return photons excited by the narrow-band single mode laser and that by the narrow-band three-mode laser are respectively calculated. The results show that the narrow-band three-mode laser with a specific spectrum structure has a higher spontaneous radiation rate and more return photons than a narrow-band single mode laser. Of note, the effect of the atmospheric turbulence on the number of return photons is remarkable. Calculation results indicate that the number of return photons under the HV5/7 model for atmospheric turbulence is much higher than that under the Greenwood and ModHV models. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  18. Ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon mediated circular strand displacement polymerization and hyperbranched rolling circle amplification.

    Science.gov (United States)

    Li, Xiaolu; Guo, Jing; Zhai, Qian; Xia, Jing; Yi, Gang

    2016-08-31

    Using a cascade signal amplification strategy, an ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon (MB) mediated circular strand displacement polymerization (CSDP) and hyperbranched rolling circle amplification (HRCA) was proposed. The hybridization of MB probe to target DNA resulted in a conformational change of the MB and triggered the CSDP in the presence of bio-primer and Klenow fragment (KF exo(-)), leading to multiple biotin-tagged DNA duplex. Furthermore, the HRCA was implemented to product amounts of double-stranded DNA (ds-DNA) fragments using phi29 DNA polymerase via biotin-streptavidin interaction. After the product of HRCA binded numerous biotinylated detection probes, an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor exhibited excellent detection sensitivity and specificity with a log-linear response to target DNA from 0.01 fM to 10 pM as low as 8.9 aM. The proposed method allowed DNA detection with simplicity, rapidness, low cost and high specificity, which might have the potential for application in clinical molecular diagnostics and environmental monitoring.

  19. Enzyme-free and label-free ultra-sensitive colorimetric detection of Pb(2+) using molecular beacon and DNAzyme based amplification strategy.

    Science.gov (United States)

    Yun, Wen; Cai, Dingzhou; Jiang, JiaoLai; Zhao, Pengxiang; Huang, Yu; Sang, Ge

    2016-06-15

    An enzyme-free and label-free colorimetric Pb(2+) sensor based on DNAzyme and molecular beacon (MB) has been developed and demonstrated by recycle using enzyme strand for signal amplification. The substrate strand DNA (S-DNA) of DNAzyme could be converted into MB structure with base pairs of stem part at the both ends. The MB could hybridize with enzyme strand DNA (E-DNA) to form DNAzyme, and be activated and cleaved in the presence of Pb(2+). The cleaved MB is much less stable, releasing from the DNAzyme as two product pieces. The product pieces of MB are flexible and could bind to unmodified AuNPs to effectively stabilize them against salt-induced aggregation. Then, the E-DNA is liberated to catalyze the next reaction and amplify the response signal. By taking advantage of repeated using of E-DNA, our proposed method exhibited high sensitive for Pb(2+) detection in a linear range from 0.05 to 5 nM with detection limit of 20 pM by UV-vis spectrometer. Moreover, this method was also used for determination of Pb(2+) in river water samples with satisfying results. Importantly, this strategy could reach high sensitivity without any modification and complex enzymatic or hairpins based amplification procedures. PMID:26836648

  20. Multiplex bioimaging of piRNA molecular pathway-regulated theragnostic effects in a single breast cancer cell using a piRNA molecular beacon.

    Science.gov (United States)

    Lee, Youn Jung; Moon, Sung Ung; Park, Min Geun; Jung, Woon Yong; Park, Yong Keun; Song, Sung Kyu; Ryu, Je Gyu; Lee, Yong Seung; Heo, Hye Jung; Gu, Ha Na; Cho, Su Jeong; Ali, Bahy A; Al-Khedhairy, Abdulaziz A; Lee, Ilkyun; Kim, Soonhag

    2016-09-01

    Recently, PIWI-interacting small non-coding RNAs (piRNAs) have emerged as novel cancer biomarkers candidate because of their high expression level in various cancer types and role in the control of tumor suppressor genes. In this study, a novel breast cancer theragnostics probe based on a single system targeting the piRNA-36026 (piR-36026) molecular pathway was developed using a piR-36026 molecular beacon (MB). The piR-36026 MB successfully visualized endogenous piR-36026 biogenesis, which is highly expressed in MCF7 cells (a human breast cancer cell line), and simultaneously inhibited piR-36026-mediated cancer progression in vitro and in vivo. We discovered two tumor suppressor proteins, SERPINA1 and LRAT, that were directly regulated as endogenous piR-36026 target genes in MCF7 cells. Furthermore, multiplex bioimaging of a single MCF7 cell following treatment with piR-36026 MB clearly visualized the direct molecular interaction of piRNA-36026 with SERPINA1 or LRAT and subsequent molecular therapeutic responses including caspase-3 and PI in the nucleus.

  1. Enzyme-free and label-free ultra-sensitive colorimetric detection of Pb(2+) using molecular beacon and DNAzyme based amplification strategy.

    Science.gov (United States)

    Yun, Wen; Cai, Dingzhou; Jiang, JiaoLai; Zhao, Pengxiang; Huang, Yu; Sang, Ge

    2016-06-15

    An enzyme-free and label-free colorimetric Pb(2+) sensor based on DNAzyme and molecular beacon (MB) has been developed and demonstrated by recycle using enzyme strand for signal amplification. The substrate strand DNA (S-DNA) of DNAzyme could be converted into MB structure with base pairs of stem part at the both ends. The MB could hybridize with enzyme strand DNA (E-DNA) to form DNAzyme, and be activated and cleaved in the presence of Pb(2+). The cleaved MB is much less stable, releasing from the DNAzyme as two product pieces. The product pieces of MB are flexible and could bind to unmodified AuNPs to effectively stabilize them against salt-induced aggregation. Then, the E-DNA is liberated to catalyze the next reaction and amplify the response signal. By taking advantage of repeated using of E-DNA, our proposed method exhibited high sensitive for Pb(2+) detection in a linear range from 0.05 to 5 nM with detection limit of 20 pM by UV-vis spectrometer. Moreover, this method was also used for determination of Pb(2+) in river water samples with satisfying results. Importantly, this strategy could reach high sensitivity without any modification and complex enzymatic or hairpins based amplification procedures.

  2. Multiplex bioimaging of piRNA molecular pathway-regulated theragnostic effects in a single breast cancer cell using a piRNA molecular beacon.

    Science.gov (United States)

    Lee, Youn Jung; Moon, Sung Ung; Park, Min Geun; Jung, Woon Yong; Park, Yong Keun; Song, Sung Kyu; Ryu, Je Gyu; Lee, Yong Seung; Heo, Hye Jung; Gu, Ha Na; Cho, Su Jeong; Ali, Bahy A; Al-Khedhairy, Abdulaziz A; Lee, Ilkyun; Kim, Soonhag

    2016-09-01

    Recently, PIWI-interacting small non-coding RNAs (piRNAs) have emerged as novel cancer biomarkers candidate because of their high expression level in various cancer types and role in the control of tumor suppressor genes. In this study, a novel breast cancer theragnostics probe based on a single system targeting the piRNA-36026 (piR-36026) molecular pathway was developed using a piR-36026 molecular beacon (MB). The piR-36026 MB successfully visualized endogenous piR-36026 biogenesis, which is highly expressed in MCF7 cells (a human breast cancer cell line), and simultaneously inhibited piR-36026-mediated cancer progression in vitro and in vivo. We discovered two tumor suppressor proteins, SERPINA1 and LRAT, that were directly regulated as endogenous piR-36026 target genes in MCF7 cells. Furthermore, multiplex bioimaging of a single MCF7 cell following treatment with piR-36026 MB clearly visualized the direct molecular interaction of piRNA-36026 with SERPINA1 or LRAT and subsequent molecular therapeutic responses including caspase-3 and PI in the nucleus. PMID:27289065

  3. Ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon mediated circular strand displacement polymerization and hyperbranched rolling circle amplification.

    Science.gov (United States)

    Li, Xiaolu; Guo, Jing; Zhai, Qian; Xia, Jing; Yi, Gang

    2016-08-31

    Using a cascade signal amplification strategy, an ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon (MB) mediated circular strand displacement polymerization (CSDP) and hyperbranched rolling circle amplification (HRCA) was proposed. The hybridization of MB probe to target DNA resulted in a conformational change of the MB and triggered the CSDP in the presence of bio-primer and Klenow fragment (KF exo(-)), leading to multiple biotin-tagged DNA duplex. Furthermore, the HRCA was implemented to product amounts of double-stranded DNA (ds-DNA) fragments using phi29 DNA polymerase via biotin-streptavidin interaction. After the product of HRCA binded numerous biotinylated detection probes, an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor exhibited excellent detection sensitivity and specificity with a log-linear response to target DNA from 0.01 fM to 10 pM as low as 8.9 aM. The proposed method allowed DNA detection with simplicity, rapidness, low cost and high specificity, which might have the potential for application in clinical molecular diagnostics and environmental monitoring. PMID:27506343

  4. High-power QCW microsecond-pulse solid-state sodium beacon laser with spiking suppression and D2b re-pumping.

    Science.gov (United States)

    Bian, Qi; Bo, Yong; Zuo, Jun-wei; Guo, Chuan; Xu, Chang; Tu, Wei; Shen, Yu; Zong, Nan; Yuan, Lei; Gao, Hong-wei; Peng, Qin-jun; Chen, Hong-bin; Feng, Lu; Jin, Kai; Wei, Kai; Cui, Da-fu; Xue, Sui-jian; Zhang, Yu-dong; Xu, Zu-yan

    2016-04-15

    A 65 W quasi-continuous-wave microsecond-pulse solid-state sodium beacon laser tuned to the sodium D2a line has been developed with a linewidth of 0.3 GHz, beam quality of M2=1.38, and pulse width of 120 μs at a repetition rate of 500 Hz by sum-frequency mixing 1319 and 1064 nm diode-pumped Nd:YAG master-oscillator power-amplifier systems. The laser wavelength stability is less than ±0.15 GHz through feedback controlling. The laser spiking due to relaxation oscillations is suppressed by inserting frequency doublers in both 1319 and 1064 nm oscillators. Sodium D2b re-pumping is accomplished by tuning the frequency of the electro-optic modulator with the right D2a-D2b offset. A bright sodium laser guide star with a photon return of 1820 photons/cm2/s was achieved with the laser system when a 32 W circular polarized beam was projected to the sky during our field test at the Xinglong Observatory. PMID:27082331

  5. High-power QCW microsecond-pulse solid-state sodium beacon laser with spiking suppression and D2b re-pumping.

    Science.gov (United States)

    Bian, Qi; Bo, Yong; Zuo, Jun-wei; Guo, Chuan; Xu, Chang; Tu, Wei; Shen, Yu; Zong, Nan; Yuan, Lei; Gao, Hong-wei; Peng, Qin-jun; Chen, Hong-bin; Feng, Lu; Jin, Kai; Wei, Kai; Cui, Da-fu; Xue, Sui-jian; Zhang, Yu-dong; Xu, Zu-yan

    2016-04-15

    A 65 W quasi-continuous-wave microsecond-pulse solid-state sodium beacon laser tuned to the sodium D2a line has been developed with a linewidth of 0.3 GHz, beam quality of M2=1.38, and pulse width of 120 μs at a repetition rate of 500 Hz by sum-frequency mixing 1319 and 1064 nm diode-pumped Nd:YAG master-oscillator power-amplifier systems. The laser wavelength stability is less than ±0.15 GHz through feedback controlling. The laser spiking due to relaxation oscillations is suppressed by inserting frequency doublers in both 1319 and 1064 nm oscillators. Sodium D2b re-pumping is accomplished by tuning the frequency of the electro-optic modulator with the right D2a-D2b offset. A bright sodium laser guide star with a photon return of 1820 photons/cm2/s was achieved with the laser system when a 32 W circular polarized beam was projected to the sky during our field test at the Xinglong Observatory.

  6. Nicking endonuclease-assisted signal amplification of a split molecular aptamer beacon for biomolecule detection using graphene oxide as a sensing platform.

    Science.gov (United States)

    Li, Xiang; Ding, Xuelian; Fan, Jing

    2015-12-01

    Sensitive and selective detection of ultralow concentrations of specific biomolecules is important in early clinical diagnoses and biomedical applications. Many types of aptasensors have been developed for the detection of various biomolecules, but usually suffer from false positive signals and high background signals. In this work, we have developed an amplified fluorescence aptasensor platform for ultrasensitive biomolecule detection based on enzyme-assisted target-recycling signal amplification and graphene oxide. By using a split molecular aptamer beacon and a nicking enzyme, the typical problem of false positive signals can be effectively resolved. Only in the presence of a target biomolecule, the sensor system is able to generate a positive signal, which significantly improves the selectivity of the aptasensor. Moreover, using graphene oxide as a super-quencher can effectively reduce the high background signal of a sensing platform. We select vascular endothelial growth factor (VEGF) and adenosine triphosphate (ATP) as model analytes in the current proof-of-concept experiments. It is shown that under optimized conditions, our strategy exhibits high sensitivity and selectivity for the quantification of VEGF and ATP with a low detection limit (1 pM and 4 nM, respectively). In addition, this biosensor has been successfully utilized in the analysis of real biological samples.

  7. Novel multifunction-integrated molecular beacon for the amplification detection of DNA hybridization based on primer/template-free isothermal polymerization.

    Science.gov (United States)

    Dong, Haiyan; Wu, Zai-Sheng; Xu, Jianguo; Ma, Ji; Zhang, Huijuan; Wang, Jie; Shen, Weiyu; Xie, Jingjing; Jia, Lee

    2015-10-15

    Molecular beacon (MB) is widely explored as a signaling probe in powerful biosensing systems, for example, enzyme-assisted strand displacement amplification (SDA)-based system. The existing polymerization-based amplification system is often composed of recognition element, primer, template and fluorescence reporter. To develop a new MB sensing system and simply the signal amplification design, we herein attempted to propose a multifunctional integrated MB (MI-MB) for the polymerization amplification detection of target DNA via introducing a G-rich fragment into the loop of MB without using any exogenous auxiliary oligonucleotide probe. Utilizing only one MI-MB probe, the p53 target gene could trigger the cycles of hybridization/polymerization/displacement, resulting in amplification of the target hybridization event. Thus, the p53 gene can be detected down to 5 × 10(-10)M with the linear response range from 5 × 10(-10)M to 4 × 10(-7)M. Using the MI-MB, we could readily discriminate the point mutation-contained p53 from the wild-type one. As a proof-of-concept study, owing to its simplicity and multifunction, including recognition, replication, amplification and signaling, the MI-MB exhibits the great potential for the development of different biosensors for various biomedical applications, especially, for early cancer diagnosis.

  8. Navigating and Positioning Based on EKF for Unmanned Underwater Vehicle from A Single Beacon%基于EKF的UUV单信标水声导航定位方法研究

    Institute of Scientific and Technical Information of China (English)

    曹方方; 刘卫东; 李娟丽

    2011-01-01

    This paper describes an underwater navigating and positioning approach based on Extended Kalman Filtering for Unmanned Undersea Vehicles, which can decrease the accumulated position errors of INS during UUV s voyage. In this navigation algorithm, the location of the beacon is known, and the beacon sends pulse singles to the UUV in certain time interval in unidirectional way, suppose that the beacon and UUV work in the way of time synchronization. The UUV can obtain the relative distance between the beacon and UUV. The moving location' trajectory can be estimated by Extended Kalman Filtering algorithm with UUV s velocity, heading angle and the relative distance. The results of the numerical simulation indicate that this way has low-cost and high precision, and especially has practical application in long-term UUV.%文章描述了基于扩展卡尔曼滤波算法的水声导航定位方法,该方法可以对UUV(无人水下航行器)进行导航估计,有效减少导航定位过程中的累积位置误差;导航模型中信标与UUV时间同步,且信标以一定时间间隔,广播发送水声脉冲信号,UUV利用信号的传输时间延迟,确定与信标之间的相对距离;通过解算UUV与信标的相对距离,以及自身的航行速度、航向角等参数变量,利用扩展卡尔曼滤波算法,可估计出UUV相对信标的位置,通过优化算法,可以有效降低定位过程中的累积位置误差;仿真结果表明,该导航定位算法实现简单、导航精度高,对未来小型UUV导航方法有很好的实用价值.

  9. 城市环境VANETS下的基于beacon控制的路由方案%Beacon-control-based routing protocols for Urban VANETS

    Institute of Scientific and Technical Information of China (English)

    黄煜栋; 王万良; 郑厚天

    2014-01-01

    车载网络(Vehicular ad hoc networks, VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息。然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能。为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control)。在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数。仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。

  10. Synthesis and sensing integration: A novel enzymatic reaction modulated Nanoclusters Beacon (NCB) "Illumination" strategy for label-free biosensing and logic gate operation.

    Science.gov (United States)

    Hong, Lu; Zhou, Fu; Wang, Guangfeng; Zhang, Xiaojun

    2016-12-15

    A novel fluorescent label-free "turn-on" NAD(+) and adenosine triphosphate (ATP) biosensing strategy is proposed by fully exploiting ligation triggered Nanocluster Beacon (NCB). In the presence of the target, the split NCB was brought to intact, which brought the C-rich sequence and enhancer sequence in close proximity resulting in the lightening of dark DNA/AgNCs ("On" mode). Further application was presented for logic gate operation and aptasensor construction. The feasibility was investigated by Ultraviolet-visible spectroscopy (UV-vis), Fluorescence, lifetime and High Resolution Transmission Electron Microscopy (HRTEM) etc. The strategy displayed good performance in the detection of NAD(+) and ATP, with the detection limit of 0.002nM and 0.001mM, the linear range of 10-1000nM and 0.003-0.01mM, respectively. Due to the DNA/AgNCs as fluorescence reporter, the completely label-free fluorescent strategy boasts the features of simplicity and low cost, and showing little reliance on the sensing environment. Meanwhile, the regulation by overhang G-rich sequence not relying on Förster energy transfer quenching manifests the high signal-to-background ratios (S/B ratios). This method not only provided a simple, economical and reliable fluorescent NAD(+) assay but also explored a flexible G-rich sequence regulated NCB probe for the fluorescent biosensors. Furthermore, this sensing mode was expanded to the application of a logic gate design, which exhibited a high performance for not only versatile biosensors construction but also for molecular computing application.

  11. Beacon-control-based Routing Protocols for Urban VANETs%面向城市环境VANETS的基于beacon控制的路由协议

    Institute of Scientific and Technical Information of China (English)

    黄欣; 余思东; 万荣泽

    2014-01-01

    车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性,这些特性为消息的传播带来挑战,路由机制是实现消息传递的关键因素;地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息;然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能;为此,针对城市环境,提出基于beacon控制的路由协议RPBC (Routing protocol with beacon control);在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数;仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能.

  12. Beacon-control-based routing protocols for Urban VANETS%城市环境VANETS下的基于beacon控制的路由方案

    Institute of Scientific and Technical Information of China (English)

    黄煜栋; 王万良; 郑厚天

    2014-01-01

    车载网络(Vehicular ad hoc networks, VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息。然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能。为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control)。在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数。仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。

  13. MiRNA-Related SNPs and Risk of Esophageal Adenocarcinoma and Barrett's Esophagus: Post Genome-Wide Association Analysis in the BEACON Consortium.

    Directory of Open Access Journals (Sweden)

    Matthew F Buas

    Full Text Available Incidence of esophageal adenocarcinoma (EA has increased substantially in recent decades. Multiple risk factors have been identified for EA and its precursor, Barrett's esophagus (BE, such as reflux, European ancestry, male sex, obesity, and tobacco smoking, and several germline genetic variants were recently associated with disease risk. Using data from the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON genome-wide association study (GWAS of 2,515 EA cases, 3,295 BE cases, and 3,207 controls, we examined single nucleotide polymorphisms (SNPs that potentially affect the biogenesis or biological activity of microRNAs (miRNAs, small non-coding RNAs implicated in post-transcriptional gene regulation, and deregulated in many cancers, including EA. Polymorphisms in three classes of genes were examined for association with risk of EA or BE: miRNA biogenesis genes (157 SNPs, 21 genes; miRNA gene loci (234 SNPs, 210 genes; and miRNA-targeted mRNAs (177 SNPs, 158 genes. Nominal associations (P0.50, and we did not find evidence for interactions between variants analyzed and two risk factors for EA/BE (smoking and obesity. This analysis provides the most extensive assessment to date of miRNA-related SNPs in relation to risk of EA and BE. While common genetic variants within components of the miRNA biogenesis core pathway appear unlikely to modulate susceptibility to EA or BE, further studies may be warranted to examine potential associations between unassessed variants in miRNA genes and targets with disease risk.

  14. An ultrasensitive SiO2-encapsulated alloyed CdZnSeS quantum dot-molecular beacon nanobiosensor for norovirus.

    Science.gov (United States)

    Adegoke, Oluwasesan; Seo, Min-Woong; Kato, Tatsuya; Kawahito, Shoji; Park, Enoch Y

    2016-12-15

    Ultrasensitive, rapid and selective diagnostic probes are urgently needed to overcome the limitations of traditional probes for norovirus (NV). Here, we report the detection of NV genogroup II via nucleic acid hybridization technology using a quantum dot (QD)-conjugated molecular beacon (MB) probe. To boost the sensitivity of the MB assay system, an ultrasensitive QD fluorophore with unique optical properties was synthesized, characterized and exploited as a fluorescence signal generator. Alloyed thioglycolic (TGA)-capped CdZnSeS QDs with a high photoluminescence (PL) quantum yield (QY) value of 92% were synthesized, and a modified silanization method was employed to encapsulate the thiol-capped QDs in a silica layer. The resulting highly luminescent alloyed SiO2-coated CdZnSeS QDs had a remarkable PL QY value of 98%. Transmission electron microscopy and dynamic light scattering confirmed the monodispersity of the alloyed nanocrystals, and zeta potential analysis confirmed their colloidal stability. Powder X-ray diffraction and PL lifetime measurements confirmed the surface modification of the QDs. The alloyed TGA-capped and SiO2-coated CdZnSeS QD-conjugated MB bioprobes detected extremely low concentrations of NV RNA. Ultrasensitive detection of low concentrations of NV RNA with a limit of detection (LOD) of 8.2copies/mL in human serum and a LOD of 9.3 copies/mL in buffer was achieved using the SiO2-coated CdZnSeS QD-MB probes, an increase in sensitivity of 3-fold compared with the detection limit for NV RNA using TGA-capped CdZnSeS QD-MBs. The additional merits of our detection system are rapidity, specificity and improved sensitivity over conventional molecular test probes.

  15. Synthesis and sensing integration: A novel enzymatic reaction modulated Nanoclusters Beacon (NCB) "Illumination" strategy for label-free biosensing and logic gate operation.

    Science.gov (United States)

    Hong, Lu; Zhou, Fu; Wang, Guangfeng; Zhang, Xiaojun

    2016-12-15

    A novel fluorescent label-free "turn-on" NAD(+) and adenosine triphosphate (ATP) biosensing strategy is proposed by fully exploiting ligation triggered Nanocluster Beacon (NCB). In the presence of the target, the split NCB was brought to intact, which brought the C-rich sequence and enhancer sequence in close proximity resulting in the lightening of dark DNA/AgNCs ("On" mode). Further application was presented for logic gate operation and aptasensor construction. The feasibility was investigated by Ultraviolet-visible spectroscopy (UV-vis), Fluorescence, lifetime and High Resolution Transmission Electron Microscopy (HRTEM) etc. The strategy displayed good performance in the detection of NAD(+) and ATP, with the detection limit of 0.002nM and 0.001mM, the linear range of 10-1000nM and 0.003-0.01mM, respectively. Due to the DNA/AgNCs as fluorescence reporter, the completely label-free fluorescent strategy boasts the features of simplicity and low cost, and showing little reliance on the sensing environment. Meanwhile, the regulation by overhang G-rich sequence not relying on Förster energy transfer quenching manifests the high signal-to-background ratios (S/B ratios). This method not only provided a simple, economical and reliable fluorescent NAD(+) assay but also explored a flexible G-rich sequence regulated NCB probe for the fluorescent biosensors. Furthermore, this sensing mode was expanded to the application of a logic gate design, which exhibited a high performance for not only versatile biosensors construction but also for molecular computing application. PMID:27453987

  16. An ultrasensitive SiO2-encapsulated alloyed CdZnSeS quantum dot-molecular beacon nanobiosensor for norovirus.

    Science.gov (United States)

    Adegoke, Oluwasesan; Seo, Min-Woong; Kato, Tatsuya; Kawahito, Shoji; Park, Enoch Y

    2016-12-15

    Ultrasensitive, rapid and selective diagnostic probes are urgently needed to overcome the limitations of traditional probes for norovirus (NV). Here, we report the detection of NV genogroup II via nucleic acid hybridization technology using a quantum dot (QD)-conjugated molecular beacon (MB) probe. To boost the sensitivity of the MB assay system, an ultrasensitive QD fluorophore with unique optical properties was synthesized, characterized and exploited as a fluorescence signal generator. Alloyed thioglycolic (TGA)-capped CdZnSeS QDs with a high photoluminescence (PL) quantum yield (QY) value of 92% were synthesized, and a modified silanization method was employed to encapsulate the thiol-capped QDs in a silica layer. The resulting highly luminescent alloyed SiO2-coated CdZnSeS QDs had a remarkable PL QY value of 98%. Transmission electron microscopy and dynamic light scattering confirmed the monodispersity of the alloyed nanocrystals, and zeta potential analysis confirmed their colloidal stability. Powder X-ray diffraction and PL lifetime measurements confirmed the surface modification of the QDs. The alloyed TGA-capped and SiO2-coated CdZnSeS QD-conjugated MB bioprobes detected extremely low concentrations of NV RNA. Ultrasensitive detection of low concentrations of NV RNA with a limit of detection (LOD) of 8.2copies/mL in human serum and a LOD of 9.3 copies/mL in buffer was achieved using the SiO2-coated CdZnSeS QD-MB probes, an increase in sensitivity of 3-fold compared with the detection limit for NV RNA using TGA-capped CdZnSeS QD-MBs. The additional merits of our detection system are rapidity, specificity and improved sensitivity over conventional molecular test probes. PMID:27348778

  17. An AUV Navigation Method Based on Range Measurement Using a Single Beacon%单信标距离测量的AUV导航方法

    Institute of Scientific and Technical Information of China (English)

    张淼; 李闻白; 王冬

    2012-01-01

    针对单信标测距导航方法中的系统可观测性和洋流干扰问题,通过建立自主水下航行器(Autonomous Underwater Vehicle,AUV)的三维运动学模型,利用线性时变系统的局部可观测性理论得到了系统关于AUV运动路径的可观测性条件,并采用扩展Kalman滤波导航算法实现了对AUV的位置和未知洋流的在线估计.仿真结果表明,对于满足系统可观测性的运动路径,该导航方法可有效抑制洋流干扰下系统的定位误差增长,使定位误差保持有界,并对未知洋流做出较为准确的估计.%The research amis at the observability of the navigation system and the disturbance of the ocean currents in the range measurement by using a single beacon. The paper proposes a three dimensional (3D) underwater navigation approach for autonomous underwater vehicle (AUV). By building the kinematic model of AUV and using the local observability theories of a linear varying system,the observability conditions in relation to 3D trajectories of AUV are obtained . And the online estimation of the AUV's position and unknown currents are achieved by means of the extended Kalman filtering navigation algorithm. Simulation results show that the navigation approach can restrain the growth of the localization errors with current disturbances to keep the errors bounded, and achieve accurate estimation of the unknown currents.

  18. Conceptual, Experimental and Compass-beacon Ontologies--The Principles, concepts and methodology of BMKI(Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    BAO Han-fei

    2005-01-01

    This article discussed the basic three components of an information unit(IU), ie the Carrier(C), Feature (F) and Value(Ⅴ), and presented and several different types of feature, including the static, relation and process features(SF ,RF and PF respectively). It also discussed about the knowledge for statistical group(KP) and for individual(KI) and the transformation mechanisms between them. Then both the philosophy and application attributes of ontology have been explored and two new concepts, ie ontology of existence(EO) and ontology of application (OA) were created. The paper gave an integrated sketch of the whole medical knowledge engineering cause,which is thought to be composed of three areas: conceptual, experimental and compass-beakon ontoloies (CO,EO, CBO, respectively). And based on those considerations BMKI achieved its fundamental formula.

  19. The quick detection of mutation site of eodon 463 in katG gene of INH resistant MTB by molecular beacon%耐异烟肼结核杆菌Kat G463condon点突变的分子信标快速检测

    Institute of Scientific and Technical Information of China (English)

    陈庆海; 府伟灵; 张雪; 王易伟; 边志衡; 匡红

    2009-01-01

    目的 应用分子信标探针检测结核杆菌耐异烟肼kat G463condon点突变,并与测序结果比较以验证该检测方法.方法 运用软件对Beacon designer设计,katG基因包含463condon的分子信标,建立其扩增体系及分子信标芯片检测方法,对扩增产物测序并作比较.结果 通过CDC相机观测到结核标准株及耐异烟肼PCR产物与分子信标杂交后荧光信号区别明显;16株耐异烟肼组与10株H37RV标准株对照组荧光信号强度比较,耐异烟肼组463condon突变检出率为37%,分子信标检测方法与测序法符合率达93%.结论 分子信标技术是一种具有高灵敏核酸点突变检测技术;分子信标芯片检测方法与测序法符合率较好.%Objective To detect the mutation site of codon 463 in katG gene of INH resistant MTB by molecular beacon probe, and verify the detecting method by comparing with gene sequencing. Methods The software Beacon designer,was used to design codon 463 molecular beacon probe and the amplification system,and then the method was compared with gene sequencing. Results The difference between PCR products from standard strain and INH resistant one is obvious in detecting the fluores-cent light by use of CDC camera. We detected and compare the fluorescent light signal of INH resistant strains group (n= 16) and H37RV standard strains group (n= 10). The detection rate of codon 463 mutation accounted for 37% by comparing the above two groups. The coincidence rate of molecular beacon detection method and sequencing assay was 93 %. Conclusion The molecular beacon method is a technology with characteristics of high sensitiveness and specificity in detecting nucleic acid. The co-incidence rate is good between molecular beacon chip way and sequencing.

  20. 低占空比无线传感器网络同步 MAC 协议最优信标间隔分析%The Optimal Beacon Interval for Synchronous MAC in Low Duty-Cycle Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    邢宇龙; 陈永锐; 易卫东; 段成华

    2016-01-01

    Energy efficiency is a fundamental theme in the design of wireless sensor networks protocols ,especially for medium access control (MAC) protocols .An energy‐efficient MAC protocol can significantly elongate the lifetime of wireless sensor networks by reducing the duty‐cycle of sensor nodes to an ultra‐low level .Synchronous MAC can be even more efficient in data transfer at the cost of requiring tight time synchronization through periodical beacon dissemination . The length of the beacon interval may greatly affect the energy efficiency of a synchronous MAC .A shorter beacon interval leads to higher synchronization cost due to frequent beacon sending and receiving ,while a longer beacon interval will lead to a larger guard time and longer idle listening due to clock drift . Therefore ,there is a tradeoff between these two parts of energy consumption .In this paper ,we investigate the optimal beacon interval for synchronous MAC in low duty‐cycle sensor networks ,and then present a strategy that adaptively utilizes the optimal beacon interval in a TDMA‐based MAC protocol (called Opt‐TDMA) .By configuring the beacon interval to its optimal value according to the data packets rate and network size ,Opt‐TDMA can reduce the overall power consumption of both sending/receiving beacons and data packets . Experimental results demonstrate that Opt‐TDMA is more energy‐efficient than pure TDMA protocol and SCP‐MAC by using optimal beacon interval and contention‐free transmission .%能量效率是无线传感器网络协议设计的首要考虑因素。无线传感器网络中,介质访问控制层(medium access control ,MAC)协议通过降低节点的占空比来降低网络能耗,延长网络的生命周期。相比其他 MAC 协议,尽管同步 MAC 需要周期性分发信标来保持严格的时间同步,但却在数据传输方面具有更高的能量效率。信标间隔的长短直接影响同步 M AC 能量效率的高低。一方面