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Sample records for small signal analyses

  1. Analysis of small-signal intensity modulation of semiconductor ...

    Indian Academy of Sciences (India)

    This paper demonstrates theoretical characterization of intensity modulation of semiconductor lasers (SL's). The study is based on a small-signal model to solve the laser rate equations taking into account suppression of optical gain. Analytical forms of the small-signal modulation response and modulation bandwidth are ...

  2. Signal Transduction Pathways of TNAP: Molecular Network Analyses.

    Science.gov (United States)

    Négyessy, László; Györffy, Balázs; Hanics, János; Bányai, Mihály; Fonta, Caroline; Bazsó, Fülöp

    2015-01-01

    Despite the growing body of evidence pointing on the involvement of tissue non-specific alkaline phosphatase (TNAP) in brain function and diseases like epilepsy and Alzheimer's disease, our understanding about the role of TNAP in the regulation of neurotransmission is severely limited. The aim of our study was to integrate the fragmented knowledge into a comprehensive view regarding neuronal functions of TNAP using objective tools. As a model we used the signal transduction molecular network of a pyramidal neuron after complementing with TNAP related data and performed the analysis using graph theoretic tools. The analyses show that TNAP is in the crossroad of numerous pathways and therefore is one of the key players of the neuronal signal transduction network. Through many of its connections, most notably with molecules of the purinergic system, TNAP serves as a controller by funnelling signal flow towards a subset of molecules. TNAP also appears as the source of signal to be spread via interactions with molecules involved among others in neurodegeneration. Cluster analyses identified TNAP as part of the second messenger signalling cascade. However, TNAP also forms connections with other functional groups involved in neuronal signal transduction. The results indicate the distinct ways of involvement of TNAP in multiple neuronal functions and diseases.

  3. Network features and pathway analyses of a signal transduction cascade

    Directory of Open Access Journals (Sweden)

    Ryoji Yanashima

    2009-05-01

    Full Text Available The scale-free and small-world network models reflect the functional units of networks. However, when we investigated the network properties of a signaling pathway using these models, no significant differences were found between the original undirected graphs and the graphs in which inactive proteins were eliminated from the gene expression data. We analyzed signaling networks by focusing on those pathways that best reflected cellular function. Therefore, our analysis of pathways started from the ligands and progressed to transcription factors and cytoskeletal proteins. We employed the Python module to assess the target network. This involved comparing the original and restricted signaling cascades as a directed graph using microarray gene expression profiles of late onset Alzheimer's disease. The most commonly used method of shortest-path analysis neglects to consider the influences of alternative pathways that can affect the activation of transcription factors or cytoskeletal proteins. We therefore introduced included k-shortest paths and k-cycles in our network analysis using the Python modules, which allowed us to attain a reasonable computational time and identify k-shortest paths. This technique reflected results found in vivo and identified pathways not found when shortest path or degree analysis was applied. Our module enabled us to comprehensively analyse the characteristics of biomolecular networks and also enabled analysis of the effects of diseases considering the feedback loop and feedforward loop control structures as an alternative path.

  4. UMTS signal measurements with digital spectrum analysers

    International Nuclear Information System (INIS)

    Licitra, G.; Palazzuoli, D.; Ricci, A. S.; Silvi, A. M.

    2004-01-01

    The launch of the Universal Mobile Telecommunications System (UNITS), the most recent mobile telecommunications standard has imposed the requirement of updating measurement instrumentation and methodologies. In order to define the most reliable measurement procedure, which is aimed at assessing the exposure to electromagnetic fields, modern spectrum analysers' features for correct signal characterisation has been reviewed. (authors)

  5. Small signal gain measurements in a small scale HF overtone laser

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, C.F.; Hewett, K.B.; Manke, G.C. II; Hager, G.D. [Air Force Research Laboratory, Directed Energy Directorate, 3550 Aberdeen Ave SE, Kirtland AFB, NM 87117-5776 (United States); Crowell, P.G. [Northrup Grumman Information Technology, Science and Technology Operating Unit, Advanced Technology Division, P.O. Box 9377, Albuquerque, NM 87119-9377 (United States); Truman, C.R. [Mechanical Engineering Department, University of New Mexico, Albuquerque, NM 87131 (United States)

    2003-07-01

    The overtone gain medium of a small-scale HF overtone laser was probed using a sub-Doppler tunable diode laser. Two-dimensional spatially resolved small signal gain and temperature maps were generated for several ro-vibrational transitions in the HF (v=2{yields}v=0) overtone band. Our results compare well with previous measurements of the overtone gain in a similar HF laser device. (orig.)

  6. An Integrated Signaling-Encryption Mechanism to Reduce Error Propagation in Wireless Communications: Performance Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Olama, Mohammed M [ORNL; Matalgah, Mustafa M [ORNL; Bobrek, Miljko [ORNL

    2015-01-01

    Traditional encryption techniques require packet overhead, produce processing time delay, and suffer from severe quality of service deterioration due to fades and interference in wireless channels. These issues reduce the effective transmission data rate (throughput) considerably in wireless communications, where data rate with limited bandwidth is the main constraint. In this paper, performance evaluation analyses are conducted for an integrated signaling-encryption mechanism that is secure and enables improved throughput and probability of bit-error in wireless channels. This mechanism eliminates the drawbacks stated herein by encrypting only a small portion of an entire transmitted frame, while the rest is not subject to traditional encryption but goes through a signaling process (designed transformation) with the plaintext of the portion selected for encryption. We also propose to incorporate error correction coding solely on the small encrypted portion of the data to drastically improve the overall bit-error rate performance while not noticeably increasing the required bit-rate. We focus on validating the signaling-encryption mechanism utilizing Hamming and convolutional error correction coding by conducting an end-to-end system-level simulation-based study. The average probability of bit-error and throughput of the encryption mechanism are evaluated over standard Gaussian and Rayleigh fading-type channels and compared to the ones of the conventional advanced encryption standard (AES).

  7. Power system small signal stability analysis and control

    CERN Document Server

    Mondal, Debasish; Sengupta, Aparajita

    2014-01-01

    Power System Small Signal Stability Analysis and Control presents a detailed analysis of the problem of severe outages due to the sustained growth of small signal oscillations in modern interconnected power systems. The ever-expanding nature of power systems and the rapid upgrade to smart grid technologies call for the implementation of robust and optimal controls. Power systems that are forced to operate close to their stability limit have resulted in the use of control devices by utility companies to improve the performance of the transmission system against commonly occurring power system

  8. Validation of Nonlinear Bipolar Transistor Model by Small-Signal Measurements

    DEFF Research Database (Denmark)

    Vidkjær, Jens; Porra, V.; Zhu, J.

    1992-01-01

    A new method for the validity analysis of nonlinear transistor models is presented based on DC-and small-signal S-parameter measurements and realistic consideration of the measurement and de-embedding errors and singularities of the small-signal equivalent circuit. As an example, some analysis...... results for an extended Gummel Poon model are presented in the case of a UHF bipolar power transistor....

  9. Trial sequential analyses of meta-analyses of complications in laparoscopic vs. small-incision cholecystectomy: more randomized patients are needed

    DEFF Research Database (Denmark)

    Keus, Frederik; Wetterslev, Jørn; Gluud, Christian

    2010-01-01

    Conclusions based on meta-analyses of randomized trials carry a status of "truth." Methodological components may identify trials with systematic errors ("bias"). Trial sequential analysis (TSA) evaluates random errors in meta-analysis. We analyzed meta-analyses on laparoscopic vs. small-incision ......Conclusions based on meta-analyses of randomized trials carry a status of "truth." Methodological components may identify trials with systematic errors ("bias"). Trial sequential analysis (TSA) evaluates random errors in meta-analysis. We analyzed meta-analyses on laparoscopic vs. small...

  10. Benchmarking of small-signal dynamics of single-phase PLLs

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    Phase-looked Loop (PLL) is a critical component for the control and grid synchronization of grid-connected power converters. This paper presents a benchmarking study on the small-signal dynamics of three commonly used PLLs for single-phase converters, including enhanced PLL, second......-order generalized integrator based PLL, and the inverse-PLL. First, a unified small-signal model of those PLLs is established for comparing their dynamics. Then, a systematic design guideline for parameters tuning of the PLLs is formulated. To confirm the validity of theoretical analysis, nonlinear time...

  11. Targeting and localized signalling by small GTPases

    NARCIS (Netherlands)

    ten Klooster, Jean Paul; Hordijk, Peter L.

    2007-01-01

    Polarized cellular responses, for example, cell migration, require the co-ordinated assembly of signalling complexes at a particular subcellular location, such as the leading edge of cells. Small GTPases of the Ras superfamily play central roles in many (polarized) responses to growth factors,

  12. Inhibition of receptor tyrosine kinase signalling by small molecule agonist of T-cell protein tyrosine phosphatase

    International Nuclear Information System (INIS)

    Mattila, Elina; Marttila, Heidi; Sahlberg, Niko; Kohonen, Pekka; Tähtinen, Siri; Halonen, Pasi; Perälä, Merja; Ivaska, Johanna

    2010-01-01

    T-cell protein tyrosine phosphatase (TCPTP/TC45) is a ubiquitously expressed intra-cellular non-receptor protein tyrosine phosphatase involved in the negative regulation of several cancer relevant cellular signalling pathways. We have previously shown that interaction between the α-cytoplasmic tail of α1β1 integrin and TCPTP activates TCPTP by disrupting an inhibitory intra-molecular bond in TCPTP. Thus, inhibition of the regulatory interaction in TCPTP is a desirable strategy for TCPTP activation and attenuation of oncogenic RTK signalling. However, this is challenging with low molecular weight compounds. We developed a high-throughput compatible assay to analyse activity of recombinant TCPTP in vitro. Using this assay we have screened 64280 small molecules to identify novel agonists for TCPTP. Dose-dependent response to TCPTP agonist was performed using the in vitro assay. Inhibition effects and specificity of TCPTP agonists were evaluated using TCPTP expressing and null mouse embryonic fibroblasts. Western blot analysis was used to evaluate attenuation of PDGFRβ and EGFR phosphorylation. Inhibition of VEGF signalling was analysed with VEGF-induced endothelial cell sprouting assays. From the screen we identified six TCPTP agonists. Two compounds competed with α1-cytoplasmic domain for binding to TCPTP, suggesting that they activate TCPTP similar to α1-cyt by disrupting the intra-molecular bond in TCPTP. Importantly, one of the compounds (spermidine) displayed specificity towards TCPTP in cells, since TCPTP -/- cells were 43-fold more resistant to the compound than TCPTP expressing cells. This compound attenuates PDGFRβ and VEGFR2 signalling in cells in a TCPTP-dependent manner and functions as a negative regulator of EGFR phosphorylation in cancer cells. In this study we showed that small molecules mimicking TCPTP-α1 interaction can be used as TCPTP agonists. These data provide the first proof-of-concept description of the use of high-throughput screening

  13. Comparison Study of Power System Small Signal Stability Improvement Using SSSC and STATCOM

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Fang, Jiakun

    2013-01-01

    the connected power system, both SSSC and STATCOM are able to participate in the power system inter-area oscillation damping by changing the compensated reactance or the provided reactive power. This paper analyses the influence of SSSC and STATCOM on power system small signal stability. The damping controller...... schemes for SSSC and STATCOM are presented and discussed. The IEEE 39-bus New England system model as the test system is built in DIgSIELNT PowerFactory, in which the damping control strategies for both SSSC and STATCOM are validated by time domain simulations and modal analysis. Furthermore, comparison......A static synchronous series compensator (SSSC) has the ability to emulate a reactance in series with the connected transmission line. A static synchronous compensator (STATCOM) is able to provide the reactive power to an electricity network. When fed with some supplementary signals from...

  14. Small signal microwave amplifier design

    CERN Document Server

    Grosch, Theodore

    2000-01-01

    This book explains techniques and examples for designing stable amplifiers for high-frequency applications in which the signal is small and the amplifier circuit is linear. An in-depth discussion of linear network theory provides the foundation needed to develop actual designs. Examples throughout the book will show you how to apply the knowledge gained in each chapter leading to the complex design of low noise amplifiers. Many exercises at the end of each chapter will help students to practice their skills. The solutions to these design problems are available in an accompanying solutions book

  15. Analysis of small-signal intensity modulation of semiconductor ...

    Indian Academy of Sciences (India)

    Computer simulation of the model is applied to 1.55-µm ... Semiconductor laser; small-signal modulation; modulation response; gain suppression. ... originates from intraband relaxation processes of charge carriers that extend for times as ...

  16. Small-signal analysis of granular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey, E-mail: aapo.varpula@tkk.f [Department of Micro and Nanosciences, Aalto University, PO Box 13500, FI-00076 Aalto, Espoo (Finland)

    2010-11-01

    The small-signal ac response of granular n-type semiconductors is calculated analytically using the drift-diffusion theory when electronic trapping at grain boundaries is present. An electrical equivalent circuit (EEC) model of a granular n-type semiconductor is presented. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is very good in a broad frequency range at low dc bias voltages.

  17. Small-signal analysis of granular semiconductors

    International Nuclear Information System (INIS)

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey

    2010-01-01

    The small-signal ac response of granular n-type semiconductors is calculated analytically using the drift-diffusion theory when electronic trapping at grain boundaries is present. An electrical equivalent circuit (EEC) model of a granular n-type semiconductor is presented. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is very good in a broad frequency range at low dc bias voltages.

  18. Small- and large-signal modeling of InP HBTs in transferred-substrate technology

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Rudolph, Matthias; Jensen, Thomas

    2014-01-01

    In this paper, the small- and large-signal modeling of InP heterojunction bipolar transistors (HBTs) in transferred substrate (TS) technology is investigated. The small-signal equivalent circuit parameters for TS-HBTs in two-terminal and three-terminal configurations are determined by employing...

  19. Improvement of small-signal stability of power system by controlling doubly fed induction generators of a large-capacity wind farm

    Directory of Open Access Journals (Sweden)

    Tomohiro Adachi

    2016-01-01

    Full Text Available Many wind turbine generations have been installed into power systems around the world, where in recent years doubly fed induction generator (DFIG attracts a lot of attentions because of its efficiency and controllability. However, the DFIG is connected to the power system through inverters and originally does not have an ability to release the kinetic energy of the rotor or resorb the surplus power of the power system as the kinetic energy. Therefore, it has not been made clear how the DFIGs have an influence on small-signal stability in power systems. In this paper, we propose a control scheme of the DFIG and analyse its effect on the small-signal stability of the power system by eigenvalue calculations and time-domain simulations.

  20. Assessment of intrinsic small signal parameters of submicron SiC MESFETs

    Science.gov (United States)

    Riaz, Mohammad; Ahmed, Muhammad Mansoor; Rafique, Umair; Ahmed, Umer Farooq

    2018-01-01

    In this paper, a technique has been developed to estimate intrinsic small signal parameters of submicron SiC MESFETs, designed for high power microwave applications. In the developed technique, small signal parameters are extracted by involving drain-to-source current, Ids instead of Schottky barrier depletion layer expression. It has been demonstrated that in SiC MESFETs, the depletion layer gets modified due to intense transverse electric field and/or self-heating effects, which are conventionally not taken into account. Thus, assessment of AC small signal parameters by employing depletion layer expression loses its accuracy for devices meant for high power applications. A set of expressions for AC small signal elements has been developed using Ids and its dependence on device biasing has been discussed. The validity of the proposed technique has been demonstrated using experimental data. Dr. Ahmed research interests are in Microelectronics, Microwave and RF Engineering and he has supervised numerous MS and PhD research projects. He authored over 100 research papers in the field of microelectronics. Dr. Ahmed is a fellow of the Institution of Engineering and Technology (IET), UK.; a Chartered Engineer (CEng) from the UK Engineering Council and holds the title of European Engineer (Eur Ing) from the European Federation of National Engineering Association (FEANI), Brussels. He is a life member of PEC (Pak); EDS & MTTS (USA).

  1. Small Displacement Detection of Biological Signals Using the Cyclic Frequency Method

    Directory of Open Access Journals (Sweden)

    Dan Zhang

    2015-01-01

    Full Text Available A new signal processing method called the Cyclic Frequency method is proposed for small displacement detection of vital signals such as heart rate and respiration using the CW radar method. We have presented experimental results of small displacement detection to confirm the validity of the method. The displacement amplitude 2.5 mm can be detected with a propagation frequency of 24.15 GHz. We may increase the propagation frequency for smaller displacement amplitude or target velocity.

  2. Improving Small Signal Stability through Operating Point Adjustment

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhenyu; Zhou, Ning; Tuffner, Francis K.; Chen, Yousu; Trudnowski, Daniel J.; Mittelstadt, William; Hauer, John F.; Dagle, Jeffery E.

    2010-09-30

    ModeMeter techniques for real-time small signal stability monitoring continue to mature, and more and more phasor measurements are available in power systems. It has come to the stage to bring modal information into real-time power system operation. This paper proposes to establish a procedure for Modal Analysis for Grid Operations (MANGO). Complementary to PSS’s and other traditional modulation-based control, MANGO aims to provide suggestions such as increasing generation or decreasing load for operators to mitigate low-frequency oscillations. Different from modulation-based control, the MANGO procedure proactively maintains adequate damping for all time, instead of reacting to disturbances when they occur. Effect of operating points on small signal stability is presented in this paper. Implementation with existing operating procedures is discussed. Several approaches for modal sensitivity estimation are investigated to associate modal damping and operating parameters. The effectiveness of the MANGO procedure is confirmed through simulation studies of several test systems.

  3. Wideband Small-Signal Input dq Admittance Modeling of Six-Pulse Diode Rectifiers

    DEFF Research Database (Denmark)

    Yue, Xiaolong; Wang, Xiongfei; Blaabjerg, Frede

    2018-01-01

    This paper studies the wideband small-signal input dq admittance of six-pulse diode rectifiers. Considering the frequency coupling introduced by ripple frequency harmonics of d-and q-channel switching function, the proposed model successfully predicts the small-signal input dq admittance of six......-pulse diode rectifiers in high frequency regions that existing models fail to explain. Simulation and experimental results verify the accuracy of the proposed model....

  4. Small Signal Loudspeaker Impedance Emulator

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Knott, Arnold

    2014-01-01

    Specifying the performance of audio amplifiers is typically done by playing sine waves into a pure ohmic load. However real loudspeaker impedances are not purely ohmic but characterized by the mechanical resonance between the mass of the diaphragm and the compliance of its suspension which vary...... from driver to driver. Therefore, a loudspeaker emulator capable of adjusting its impedance to that of a given driver is desired for measurement purposes. This paper proposes a loudspeaker emulator circuit for small signals. Simulations and experimental results are compared and show that it is possible...... to emulate the loudspeaker impedance with an electric circuit and that its resonance frequency can be changed by tuning two resistors....

  5. Small-signal Loudspeaker Impedance Emulator

    DEFF Research Database (Denmark)

    Knott, Arnold; Iversen, Niels Elkjær

    2014-01-01

    Specifying the performance of audio ampliers is typically done by playing sine waves into a pure ohmic load. However real loudspeaker impedances are not purely ohmic but characterised by the mechanical resonance between the mass of the diaphragm and the compliance of its' suspension which vary from...... driver to driver. Therefore a loudspeaker emulator capable of adjusting its' impedance to a given driver is in need for measurement purposes. This paper proposes a loudspeaker emulator circuit for small signals. Simulations and experimental results are compared and show that it is possible to emulate...... the loudspeaker impedance with an electric circuit and that its' resonance frequency can be changed by tuning two resistors....

  6. TSH Receptor Signaling Abrogation by a Novel Small Molecule.

    Science.gov (United States)

    Latif, Rauf; Realubit, Ronald B; Karan, Charles; Mezei, Mihaly; Davies, Terry F

    2016-01-01

    Pathological activation of the thyroid-stimulating hormone receptor (TSHR) is caused by thyroid-stimulating antibodies in patients with Graves' disease (GD) or by somatic and rare genomic mutations that enhance constitutive activation of the receptor influencing both G protein and non-G protein signaling. Potential selective small molecule antagonists represent novel therapeutic compounds for abrogation of such abnormal TSHR signaling. In this study, we describe the identification and in vitro characterization of a novel small molecule antagonist by high-throughput screening (HTS). The identification of the TSHR antagonist was performed using a transcription-based TSH-inhibition bioassay. TSHR-expressing CHO cells, which also expressed a luciferase-tagged CRE response element, were optimized using bovine TSH as the activator, in a 384 well plate format, which had a Z score of 0.3-0.6. Using this HTS assay, we screened a diverse library of ~80,000 compounds at a final concentration of 16.7 μM. The selection criteria for a positive hit were based on a mean signal threshold of ≥50% inhibition of control TSH stimulation. The screening resulted in 450 positive hits giving a hit ratio of 0.56%. A secondary confirmation screen against TSH and forskolin - a post receptor activator of adenylyl cyclase - confirmed one TSHR-specific candidate antagonist molecule (named VA-K-14). This lead molecule had an IC 50 of 12.3 μM and a unique chemical structure. A parallel analysis for cell viability indicated that the lead inhibitor was non-cytotoxic at its effective concentrations. In silico docking studies performed using a TSHR transmembrane model showed the hydrophobic contact locations and the possible mode of inhibition of TSHR signaling. Furthermore, this molecule was capable of inhibiting TSHR stimulation by GD patient sera and monoclonal-stimulating TSHR antibodies. In conclusion, we report the identification of a novel small molecule TSHR inhibitor, which has the

  7. Comprehensive logic based analyses of Toll-like receptor 4 signal transduction pathway.

    Directory of Open Access Journals (Sweden)

    Mahesh Kumar Padwal

    Full Text Available Among the 13 TLRs in the vertebrate systems, only TLR4 utilizes both Myeloid differentiation factor 88 (MyD88 and Toll/Interleukin-1 receptor (TIR-domain-containing adapter interferon-β-inducing Factor (TRIF adaptors to transduce signals triggering host-protective immune responses. Earlier studies on the pathway combined various experimental data in the form of one comprehensive map of TLR signaling. But in the absence of adequate kinetic parameters quantitative mathematical models that reveal emerging systems level properties and dynamic inter-regulation among the kinases/phosphatases of the TLR4 network are not yet available. So, here we used reaction stoichiometry-based and parameter independent logical modeling formalism to build the TLR4 signaling network model that captured the feedback regulations, interdependencies between signaling kinases and phosphatases and the outcome of simulated infections. The analyses of the TLR4 signaling network revealed 360 feedback loops, 157 negative and 203 positive; of which, 334 loops had the phosphatase PP1 as an essential component. The network elements' interdependency (positive or negative dependencies in perturbation conditions such as the phosphatase knockout conditions revealed interdependencies between the dual-specific phosphatases MKP-1 and MKP-3 and the kinases in MAPK modules and the role of PP2A in the auto-regulation of Calmodulin kinase-II. Our simulations under the specific kinase or phosphatase gene-deficiency or inhibition conditions corroborated with several previously reported experimental data. The simulations to mimic Yersinia pestis and E. coli infections identified the key perturbation in the network and potential drug targets. Thus, our analyses of TLR4 signaling highlights the role of phosphatases as key regulatory factors in determining the global interdependencies among the network elements; uncovers novel signaling connections; identifies potential drug targets for

  8. Small-Signal Dynamic Analysis of LCC-HVDC with STATCOM at the Inverter Busbar

    Science.gov (United States)

    Liu, Dong; Jiang, Wen; Guo, Chunyi; Rehman, Atiq Ur; Zhao, Chengyong

    2018-01-01

    This paper develops a linearized small-signal dynamic model of a Line-Commutated-Converter based HVDC (LCC-HVDC) system with STATCOM at the inverter busbar, and validates its accuracy by comparing time-domain responses from small-signal model and PSCAD-based simulation results. Considering the potential impact of Phase-Locked-Loop (PLL) parameters on the study system and the close connection of STATCOM and LCC inverter station at AC busbar, this paper investigates the impact of PLL gains and AC voltage control parameters of STATCOM on the system small-signal stability. The studies show that (i) the PLL gain has highly impact on the study system and smaller PLL gains are preferable; (ii) larger values of both the proportional gain and the integral gain of AC voltage controller of STATCOM could result in oscillation/instability of the system.

  9. Discovery of novel small molecule activators of β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Folkert Verkaar

    Full Text Available Wnt/β-catenin signaling plays a major role in embryonic development and adult stem cell maintenance. Reduced activation of the Wnt/β-catenin pathway underlies neurodegenerative disorders and aberrations in bone formation. Screening of a small molecule compound library with a β-galactosidase fragment complementation assay measuring β-catenin nuclear entry revealed bona fide activators of β-catenin signaling. The compounds stabilized cytoplasmic β-catenin and activated β-catenin-dependent reporter gene activity. Although the mechanism through which the compounds activate β-catenin signaling has yet to be determined, several key regulators of Wnt/β-catenin signaling, including glycogen synthase kinase 3 and Frizzled receptors, were excluded as the molecular target. The compounds displayed remarkable selectivity, as they only induced β-catenin signaling in a human osteosarcoma U2OS cell line and not in a variety of other cell lines examined. Our data indicate that differences in cellular Wnt/β-catenin signaling machinery can be exploited to identify cell type-specific activators of Wnt/β-catenin signaling.

  10. Comparative study of probabilistic methodologies for small signal stability assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rueda, J.L.; Colome, D.G. [Universidad Nacional de San Juan (IEE-UNSJ), San Juan (Argentina). Inst. de Energia Electrica], Emails: joseluisrt@iee.unsj.edu.ar, colome@iee.unsj.edu.ar

    2009-07-01

    Traditional deterministic approaches for small signal stability assessment (SSSA) are unable to properly reflect the existing uncertainties in real power systems. Hence, the probabilistic analysis of small signal stability (SSS) is attracting more attention by power system engineers. This paper discusses and compares two probabilistic methodologies for SSSA, which are based on the two point estimation method and the so-called Monte Carlo method, respectively. The comparisons are based on the results obtained for several power systems of different sizes and with different SSS performance. It is demonstrated that although with an analytical approach the amount of computation of probabilistic SSSA can be reduced, the different degrees of approximations that are adopted, lead to deceptive results. Conversely, Monte Carlo based probabilistic SSSA can be carried out with reasonable computational effort while holding satisfactory estimation precision. (author)

  11. Small-signal model for the series resonant converter

    Science.gov (United States)

    King, R. J.; Stuart, T. A.

    1985-01-01

    The results of a previous discrete-time model of the series resonant dc-dc converter are reviewed and from these a small signal dynamic model is derived. This model is valid for low frequencies and is based on the modulation of the diode conduction angle for control. The basic converter is modeled separately from its output filter to facilitate the use of these results for design purposes. Experimental results are presented.

  12. Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method

    Energy Technology Data Exchange (ETDEWEB)

    ChavarrIas, C; Vaquero, J J; Sisniega, A; RodrIguez-Ruano, A; Soto-Montenegro, M L; GarcIa-Barreno, P; Desco, M [Unidad de Medicina y CirugIa Experimental, Hospital General Universitario Gregorio Maranon, Anexo PsiquiatrIa, 1 Planta. C/Ibiza, 43. Madrid 28007 (Spain)

    2008-09-07

    We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, subtraction of their average image from each individual frame produces a set of difference images. Pixels in these images have positive or negative values (according to the respiratory phase) in those areas where there is lung movement. The respiratory signals were extracted by analysing the shape of the histogram of these difference images: we calculated the first four central and non-central moments. However, only odd-order moments produced the desired breathing signal, as the even-order moments lacked information about the phase. Each of these curves was compared to a reference signal recorded by means of a pneumatic pillow. Given the similar correlation coefficients yielded by all of them, we selected the mean to implement our retrospective protocol. Respiratory phase bins were separated, reconstructed independently and included in a dynamic sequence, suitable for cine playback. We validated our method in five adult rat studies by comparing profiles drawn across the diaphragm dome, with and without retrospective respiratory gating. Results showed a sharper transition in the gated reconstruction, with an average slope improvement of 60.7%.

  13. Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method

    International Nuclear Information System (INIS)

    ChavarrIas, C; Vaquero, J J; Sisniega, A; RodrIguez-Ruano, A; Soto-Montenegro, M L; GarcIa-Barreno, P; Desco, M

    2008-01-01

    We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, subtraction of their average image from each individual frame produces a set of difference images. Pixels in these images have positive or negative values (according to the respiratory phase) in those areas where there is lung movement. The respiratory signals were extracted by analysing the shape of the histogram of these difference images: we calculated the first four central and non-central moments. However, only odd-order moments produced the desired breathing signal, as the even-order moments lacked information about the phase. Each of these curves was compared to a reference signal recorded by means of a pneumatic pillow. Given the similar correlation coefficients yielded by all of them, we selected the mean to implement our retrospective protocol. Respiratory phase bins were separated, reconstructed independently and included in a dynamic sequence, suitable for cine playback. We validated our method in five adult rat studies by comparing profiles drawn across the diaphragm dome, with and without retrospective respiratory gating. Results showed a sharper transition in the gated reconstruction, with an average slope improvement of 60.7%

  14. Small-Signal Stability Analysis of Full-Load Converter Interfaced Wind Turbines

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Akhmatov, Vladislav; Nielsen, Jørgen Nygård

    2009-01-01

    focus since the share of wind power increases substituting power generation from conventional power plants. Here, a study based on modal analysis is presented which investigate the effect of large scale integration of full-load converter interfaced wind turbines on inter-area oscillations in a three...... generator network. A detailed aggregated wind turbine model is employed which includes all necessary control functions. It is shown that the wind urbines have very low participation in the inter-area power oscillation.......Power system stability investigations of wind farms often cover the tasks of low-voltage-fault-ride-through, voltage and reactive power control, and power balancing, but not much attention has yet been paid to the task of small-signal stability. Small-signal stability analysis needs increasing...

  15. Nonlinear buckling analyses of a small-radius carbon nanotube

    International Nuclear Information System (INIS)

    Liu, Ning; Li, Min; Jia, Jiao; Wang, Yong-Gang

    2014-01-01

    Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained

  16. Nonlinear buckling analyses of a small-radius carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ning, E-mail: liuxiao@ase.buaa.edu.cn; Li, Min; Jia, Jiao [School of Aeronautic Science and Engineering, Beihang University, Beijing 100091 (China); Wang, Yong-Gang [Department of Applied Mechanics, China Agricultural University, Beijing 100083 (China)

    2014-04-21

    Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained.

  17. Transistor Small Signal Analysis under Radiation Effects

    International Nuclear Information System (INIS)

    Sharshar, K.A.A.

    2004-01-01

    A Small signal transistor parameters dedicate the operation of bipolar transistor before and after exposed to gamma radiation (1 Mrad up to 5 Mrads) and electron beam(1 MeV, 25 mA) with the same doses as a radiation sources, the electrical parameters of the device are changed. The circuit Model has been discussed.Parameters, such as internal emitter resistance (re), internal base resistance, internal collector resistance (re), emitter base photocurrent (Ippe) and base collector photocurrent (Ippe). These parameters affect on the operation of the device in its applications, which work as an effective element, such as current gain (hFE≡β)degradation it's and effective parameter in the device operation. Also the leakage currents (IcBO) and (IEBO) are most important parameters, Which increased with radiation doses. Theoretical representation of the change in the equivalent circuit for NPN and PNP bipolar transistor were discussed, the input and output parameters of the two types were discussed due to the change in small signal input resistance of the two types. The emitter resistance(re) were changed by the effect of gamma and electron beam irradiation, which makes a change in the role of matching impedances between transistor stages. Also the transistor stability factors S(Ico), S(VBE) and S(β are detected to indicate the transistor operations after exposed to radiation fields. In low doses the gain stability is modified due to recombination of induced charge generated during device fabrication. Also the load resistance values are connected to compensate the effect

  18. A Bioassay System Using Bioelectric Signals from Small Fish

    Science.gov (United States)

    Terawaki, Mitsuru; Soh, Zu; Hirano, Akira; Tsuji, Toshio

    Although the quality of tap water is generally examined using chemical assay, this method cannot be used for examination in real time. Against such a background, the technique of fish bioassay has attracted attention as an approach that enables constant monitoring of aquatic contamination. The respiratory rhythms of fish are considered an efficient indicator for the ongoing assessment of water quality, since they are sensitive to chemicals and can be indirectly measured from bioelectric signals generated by breathing. In order to judge aquatic contamination accurately, it is necessary to measure bioelectric signals from fish swimming freely as well as to stably discriminate measured signals, which vary between individuals. However, no bioassay system meeting the above requirements has yet been established. This paper proposes a bioassay system using bioelectric signals generated from small fish in free-swimming conditions. The system records signals using multiple electrodes to cover the extensive measurement range required in a free-swimming environment, and automatically discriminates changes in water quality from signal frequency components. This discrimination is achieved through an ensemble classification method using probability neural networks to solve the problem of differences between individual fish. The paper also reports on the results of related validation experiments, which showed that the proposed system was able to stably discriminate between water conditions before and after bleach exposure.

  19. Enhancement of small signal stability of a DFIG-based wind power ...

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology ... logic controllers for enhancing the small signal stability of DFIG-based wind integrated power system. ... state space model, eigenvalue analysis, fuzzy logic based tuning circuits ...

  20. Security region-based small signal stability analysis of power systems with FSIG based wind farm

    Science.gov (United States)

    Qin, Chao; Zeng, Yuan; Yang, Yang; Cui, Xiaodan; Xu, Xialing; Li, Yong

    2018-02-01

    Based on the Security Region approach, the impact of fixed-speed induction generator based wind farm on the small signal stability of power systems is analyzed. Firstly, the key factors of wind farm on the small signal stability of power systems are analyzed and the parameter space for small signal stability region is formed. Secondly, the small signal stability region of power systems with wind power is established. Thirdly, the corresponding relation between the boundary of SSSR and the dominant oscillation mode is further studied. Results show that the integration of fixed-speed induction generator based wind farm will cause the low frequency oscillation stability of the power system deteriorate. When the output of wind power is high, the oscillation stability of the power system is mainly concerned with the inter-area oscillation mode caused by the integration of the wind farm. Both the active power output and the capacity of reactive power compensation of the wind farm have a significant influence on the SSSR. To improve the oscillation stability of power systems with wind power, it is suggested to reasonably set the reactive power compensation capacity for the wind farm through SSSR.

  1. Small-signal analysis in high-energy physics: A Bayesian approach

    International Nuclear Information System (INIS)

    Prosper, H.B.

    1988-01-01

    The statistics of small signals masked by a background of imprecisely known magnitude is addressed from a Bayesian viewpoint using a simple statistical model which may be derived from the principle of maximum entropy. The issue of the correct assignment of prior probabilities is resolved by invoking an invariance principle proposed by Jaynes. We calculate the posterior probability and use it to calculate point estimates and upper limits for the magnitude of the signal. The results are applicable to high-energy physics experiments searching for new phenomena. We illustrate this by reanalyzing some published data from a few experiments

  2. COCAP: a carbon dioxide analyser for small unmanned aircraft systems

    Science.gov (United States)

    Kunz, Martin; Lavric, Jost V.; Gerbig, Christoph; Tans, Pieter; Neff, Don; Hummelgård, Christine; Martin, Hans; Rödjegård, Henrik; Wrenger, Burkhard; Heimann, Martin

    2018-03-01

    Unmanned aircraft systems (UASs) could provide a cost-effective way to close gaps in the observation of the carbon cycle, provided that small yet accurate analysers are available. We have developed a COmpact Carbon dioxide analyser for Airborne Platforms (COCAP). The accuracy of COCAP's carbon dioxide (CO2) measurements is ensured by calibration in an environmental chamber, regular calibration in the field and by chemical drying of sampled air. In addition, the package contains a lightweight thermal stabilisation system that reduces the influence of ambient temperature changes on the CO2 sensor by 2 orders of magnitude. During validation of COCAP's CO2 measurements in simulated and real flights we found a measurement error of 1.2 µmol mol-1 or better with no indication of bias. COCAP is a self-contained package that has proven well suited for the operation on board small UASs. Besides carbon dioxide dry air mole fraction it also measures air temperature, humidity and pressure. We describe the measurement system and our calibration strategy in detail to support others in tapping the potential of UASs for atmospheric trace gas measurements.

  3. Ultrasonic Detection of Small Crack in Studs[Bolts] by Time Difference of Thread Signals(TDTS)

    International Nuclear Information System (INIS)

    Suh, D. M.; Park, D. Y.; Kim, C. K.

    1990-01-01

    It is difficult to detect such flaws as stress - corrosion cracking or corrosion wastage(loss of bolt diameter) in the threads. In many cases the critical size of a flaw is very small(1-2 mm order). This paper describes how it is possible to discriminate small flaw indications in threads using the time difference or thread signals(TDTS) by a signal-conditioning technique

  4. Extreme Temperature Performance of Automotive-Grade Small Signal Bipolar Junction Transistors

    Science.gov (United States)

    Boomer, Kristen; Damron, Benny; Gray, Josh; Hammoud, Ahmad

    2018-01-01

    Electronics designed for space exploration missions must display efficient and reliable operation under extreme temperature conditions. For example, lunar outposts, Mars rovers and landers, James Webb Space Telescope, Europa orbiter, and deep space probes represent examples of missions where extreme temperatures and thermal cycling are encountered. Switching transistors, small signal as well as power level devices, are widely used in electronic controllers, data instrumentation, and power management and distribution systems. Little is known, however, about their performance in extreme temperature environments beyond their specified operating range; in particular under cryogenic conditions. This report summarizes preliminary results obtained on the evaluation of commercial-off-the-shelf (COTS) automotive-grade NPN small signal transistors over a wide temperature range and thermal cycling. The investigations were carried out to establish a baseline on functionality of these transistors and to determine suitability for use outside their recommended temperature limits.

  5. Small molecule inhibitors of the Candida albicans budded-to-hyphal transition act through multiple signaling pathways.

    Directory of Open Access Journals (Sweden)

    John Midkiff

    Full Text Available The ability of the pathogenic yeast Candida albicans to interconvert between budded and hyphal growth states, herein termed the budded-to-hyphal transition (BHT, is important for C. albicans development and virulence. The BHT is under the control of multiple cell signaling pathways that respond to external stimuli, including nutrient availability, high temperature, and pH. Previous studies identified 21 small molecules that could inhibit the C. albicans BHT in response to carbon limitation in Spider media. However, the studies herein show that the BHT inhibitors had varying efficacies in other hyphal-inducing media, reflecting their varying abilities to block signaling pathways associated with the different media. Chemical epistasis analyses suggest that most, but not all, of the BHT inhibitors were acting through either the Efg1 or Cph1 signaling pathways. Notably, the BHT inhibitor clozapine, a FDA-approved drug used to treat atypical schizophrenia by inhibiting G-protein-coupled dopamine receptors in the brain, and several of its functional analogs were shown to act at the level of the Gpr1 G-protein-coupled receptor. These studies are the first step in determining the target and mechanism of action of these BHT inhibitors, which may have therapeutic anti-fungal utility in the future.

  6. The origin and effect of small RNA signaling in plants

    Directory of Open Access Journals (Sweden)

    Jean-Sébastien eParent

    2012-08-01

    Full Text Available Given their sessile condition, land plants need to integrate environmental cues rapidly and send signal throughout the organism to modify their metabolism accordingly. Small RNA (sRNA molecules are among the messengers that plant cells use to carry such signals. These molecules originate from fold-back stem-loops transcribed from endogenous loci or from perfect double-stranded RNA produced through the action of RNA-dependent RNA polymerases. Once produced, sRNAs associate with Argonaute and other proteins to form the RNA-induced silencing complex (RISC that executes silencing of complementary RNA molecules. Depending on the nature of the RNA target and the Argonaute protein involved, RISC triggers either DNA methylation and chromatin modification (leading to transcriptional gene silencing, TGS or RNA cleavage or translational inhibition (leading to post-transcriptional gene silencing, PTGS. In some cases, sRNAs move to neighboring cells and/or to the vascular tissues for long-distance trafficking. Many genes are involved in the biogenesis of sRNAs and recent studies have shown that both their origin and their protein partners have great influence on their activity and range. Here we summarize the work done to uncover the mode of action of the different classes of small RNA with special emphasis on their movement and how plants can take advantage of their mobility. We also review the various genetic requirements needed for production, movement and perception of the silencing signal.

  7. Research on a Small Signal Stability Region Boundary Model of the Interconnected Power System with Large-Scale Wind Power

    Directory of Open Access Journals (Sweden)

    Wenying Liu

    2015-03-01

    Full Text Available For the interconnected power system with large-scale wind power, the problem of the small signal stability has become the bottleneck of restricting the sending-out of wind power as well as the security and stability of the whole power system. Around this issue, this paper establishes a small signal stability region boundary model of the interconnected power system with large-scale wind power based on catastrophe theory, providing a new method for analyzing the small signal stability. Firstly, we analyzed the typical characteristics and the mathematic model of the interconnected power system with wind power and pointed out that conventional methods can’t directly identify the topological properties of small signal stability region boundaries. For this problem, adopting catastrophe theory, we established a small signal stability region boundary model of the interconnected power system with large-scale wind power in two-dimensional power injection space and extended it to multiple dimensions to obtain the boundary model in multidimensional power injection space. Thirdly, we analyzed qualitatively the topological property’s changes of the small signal stability region boundary caused by large-scale wind power integration. Finally, we built simulation models by DIgSILENT/PowerFactory software and the final simulation results verified the correctness and effectiveness of the proposed model.

  8. Small Molecules Inspired by the Natural Product Withanolides as Potent Inhibitors of Wnt Signaling.

    Science.gov (United States)

    Sheremet, Michael; Kapoor, Shobhna; Schröder, Peter; Kumar, Kamal; Ziegler, Slava; Waldmann, Herbert

    2017-09-19

    Wnt signaling is a fundamental pathway that drives embryonic development and is essential for stem cell maintenance and tissue homeostasis. Dysregulation of Wnt signaling is linked to various diseases, and a constitutively active Wnt pathway drives tumorigenesis. Thus, disruption of the Wnt response is deemed a promising strategy for cancer drug discovery. However, only few clinical drug candidates that target Wnt signaling are available so far, and new small-molecule modulators of Wnt-related processes are in high demand. Here we describe the synthesis of small molecules inspired by withanolide natural products by using a pregnenolone-derived β-lactone as the key intermediate that was transformed into a δ-lactone appended to the D-ring of the steroidal scaffold. This natural-product-inspired compound library contained potent inhibitors of Wnt signaling that act upstream of the destruction complex to stabilize Axin in a tankyrase-independent manner. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Small Signal Stability Improvement of Power Systems Using Optimal Load Responses in Competitive Electricity Markets

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Chen, Zhe

    2011-01-01

    Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift some of their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to an electricity price...... price is proposed. A 17-bus power system with high wind power penetrations, which resembles the Eastern Danish power system, is chosen as the study case. Simulation results show that the optimal load response to electricity prices is an effective measure to improve the small signal stability of power...... for demand side management generates different load profiles and may provide an opportunity to improve the small signal stability of power systems with high wind power penetrations. In this paper, the idea of power system small signal stability improvement by using optimal load response to the electricity...

  10. Asymmetric double Langmuir probe: Small signal application

    International Nuclear Information System (INIS)

    Uckan, T.

    1987-11-01

    We discuss the asymmetric double Langmuir probe (ADLP) and demonstrate the possibility of using it to measure plasma temperature T/sub e/ and density n when it is operated in the region of small signal response. The area of one of the ADLP collectors is considerably larger than the other. This probe can be operated at a relatively low applied voltage, eV/sub a/T/sub e/ < 1, and still provides sufficient information to determine the plasma T/sub e/ and n. There is no need for a direct measurement of the ion saturation current, which can be on the order of a few amperes in large fusion devices. This reduces the requirements on the probe power supply. 6 refs., 6 figs

  11. Attitude stability analyses for small artificial satellites

    International Nuclear Information System (INIS)

    Silva, W R; Zanardi, M C; Formiga, J K S; Cabette, R E S; Stuchi, T J

    2013-01-01

    The objective of this paper is to analyze the stability of the rotational motion of a symmetrical spacecraft, in a circular orbit. The equilibrium points and regions of stability are established when components of the gravity gradient torque acting on the spacecraft are included in the equations of rotational motion, which are described by the Andoyer's variables. The nonlinear stability of the equilibrium points of the rotational motion is analysed here by the Kovalev-Savchenko theorem. With the application of the Kovalev-Savchenko theorem, it is possible to verify if they remain stable under the influence of the terms of higher order of the normal Hamiltonian. In this paper, numerical simulations are made for a small hypothetical artificial satellite. Several stable equilibrium points were determined and regions around these points have been established by variations in the orbital inclination and in the spacecraft principal moment of inertia. The present analysis can directly contribute in the maintenance of the spacecraft's attitude

  12. Small Molecules Affect Human Dental Pulp Stem Cell Properties Via Multiple Signaling Pathways

    Science.gov (United States)

    Al-Habib, Mey; Yu, Zongdong

    2013-01-01

    One fundamental issue regarding stem cells for regenerative medicine is the maintenance of stem cell stemness. The purpose of the study was to test whether small molecules can enhance stem cell properties of mesenchymal stem cells (MSCs) derived from human dental pulp (hDPSCs), which have potential for multiple clinical applications. We identified the effects of small molecules (Pluripotin (SC1), 6-bromoindirubin-3-oxime and rapamycin) on the maintenance of hDPSC properties in vitro and the mechanisms involved in exerting the effects. Primary cultures of hDPSCs were exposed to optimal concentrations of these small molecules. Treated hDPSCs were analyzed for their proliferation, the expression levels of pluripotent and MSC markers, differentiation capacities, and intracellular signaling activations. We found that small molecule treatments decreased cell proliferation and increased the expression of STRO-1, NANOG, OCT4, and SOX2, while diminishing cell differentiation into odonto/osteogenic, adipogenic, and neurogenic lineages in vitro. These effects involved Ras-GAP-, ERK1/2-, and mTOR-signaling pathways, which may preserve the cell self-renewal capacity, while suppressing differentiation. We conclude that small molecules appear to enhance the immature state of hDPSCs in culture, which may be used as a strategy for adult stem cell maintenance and extend their capacity for regenerative applications. PMID:23573877

  13. Wide Area Prosumption Control and Sensitivities of Aperiodic Small Signal Stability Indicators

    DEFF Research Database (Denmark)

    Wittrock, Martin Lindholm; Jóhannsson, Hjörtur; Nielsen, Arne Hejde

    2014-01-01

    and patterns, stability indicators for aperiodic small signal angular stability (ASSA) are examined, while the concept of prosumption is described. The methodology presented is shown to be able to assess the margin to instability and to predict how this margin can be affected if a load is changed in the grid...

  14. Wide-Area Assessment of Aperiodic Small Signal Rotor Angle Stability in Real-Time

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Nielsen, Arne Hejde; Østergaard, Jacob

    2014-01-01

    in rotor angle and a loss of synchronism, referred to as aperiodic small signal instability. The paper provides the theoretical background of the method and an analytical assessment criterion. Furthermore, a mathematical mapping of the generators' operating points that enables informative visualization...

  15. Effect of placement of droop based generators in distribution network on small signal stability margin and network loss

    DEFF Research Database (Denmark)

    Dheer, D.K.; Doolla, S.; Bandyopadhyay, S.

    2017-01-01

    , small signal stability margin is on the fore. The present research studied the effect of location of droop-controlled DGs on small signal stability margin and network loss on a modified IEEE 13 bus system, an IEEE 33-bus distribution system and a practical 22-bus radial distribution network. A complete...... loss and stability margin is further investigated by identifying the Pareto fronts for modified IEEE 13 bus, IEEE 33 and practical 22-bus radial distribution network with application of Reference point based Non-dominated Sorting Genetic Algorithm (R-NSGA). Results were validated by time domain......For a utility-connected system, issues related to small signal stability with Distributed Generators (DGs) are insignificant due to the presence of a very strong grid. Optimally placed sources in utility connected microgrid system may not be optimal/stable in islanded condition. Among others issues...

  16. Use of the squeezed (sub-Poisson) state of light in small-signal detection with preamplification upon four-wave mixing

    International Nuclear Information System (INIS)

    Kozlovskii, Andrei V

    2007-01-01

    The scheme of an active interferometer for amplification of small optical signals for their subsequent photodetection is proposed. The scheme provides a considerable amplification of signals by preserving their quantum-statistical properties (ideal amplification) and also can improve these properties under certain conditions. The two-mode squeezed state of light produced upon four-wave mixing, which is used for signal amplification, can be transformed to the non-classical state of the output field squeezed in the number of photons. The scheme is phase-sensitive upon amplification of the input coherent signal. It is shown that in the case of the incoherent input signal with the average number of photons (n s )∼1, the amplification process introduces no additional quantum noise at signal amplification as large as is wished. A scheme is also proposed for the cascade small-signal amplification ((n s )∼1) in the coherent state producing the amplified signal in the squeezed sub-Poisson state, which can be used for the high-resolution detection of weak and ultraweak optical signals. (quantum optics)

  17. Small-Signal Stability of Wind Power System With Full-Load Converter Interfaced Wind Turbines

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Nielsen, Jørgen Nygaard; Jensen, Kim Høj

    2012-01-01

    Small-signal stability analysis of power system oscillations is a well established field within power system analysis, but not much attention has yet been paid to systems with a high penetration of wind turbines and with large wind power plants (WPP). In this paper a comprehensive analysis...... is presented which assesses the impact of full-load converter interfaced wind turbines on power system small-signal stability. The study is based on a 7 generator network with lightly damped inter-area modes. A detailed wind turbine (WT) model with all grid relevant control functions is used in the study....... The WT is, furthermore, equipped with a park level WPP voltage controller and comparisons are presented. The WT model for this work is a validated dynamic model of the 3.6 MW Siemens Wind Power WT. The study is based on modal analysis which is complemented with time domain simulations on the nonlinear...

  18. Impact of Wind Power Plants with Full Converter Wind Turbines on Power System Small-Signal Stability

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Nygaard Nielsen, Jørgen; Dixon, Andrew

    Wind power is being developed in power systems all around the world, and already today wind power covers more than 20 % of the electricity consumption in some countries. As the size of each wind power plant (WPP) increases and as the levels of penetration reaches certain magnitudes, the inclusion...... of the dynamic properties of the WPPs in the power system stability studies become important. The work presented in this report deal with the impact of WPPs based on full converter wind turbines (WTs) on the power system small-signal rotor angle stability. During small disturbances in the power system, the rotor...... speed of the synchronous machines will eventually return to its steady state if the power system is small-signal stable. The dynamic properties of a WPP are fundamentally dierent from those of a synchronous machine, and the interaction of WPPs with the synchronous machines in power system oscillations...

  19. Gray bootstrap method for estimating frequency-varying random vibration signals with small samples

    Directory of Open Access Journals (Sweden)

    Wang Yanqing

    2014-04-01

    Full Text Available During environment testing, the estimation of random vibration signals (RVS is an important technique for the airborne platform safety and reliability. However, the available methods including extreme value envelope method (EVEM, statistical tolerances method (STM and improved statistical tolerance method (ISTM require large samples and typical probability distribution. Moreover, the frequency-varying characteristic of RVS is usually not taken into account. Gray bootstrap method (GBM is proposed to solve the problem of estimating frequency-varying RVS with small samples. Firstly, the estimated indexes are obtained including the estimated interval, the estimated uncertainty, the estimated value, the estimated error and estimated reliability. In addition, GBM is applied to estimating the single flight testing of certain aircraft. At last, in order to evaluate the estimated performance, GBM is compared with bootstrap method (BM and gray method (GM in testing analysis. The result shows that GBM has superiority for estimating dynamic signals with small samples and estimated reliability is proved to be 100% at the given confidence level.

  20. A transfer function approach to the small-signal response of saturated semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup; Blumenthal, D. J.; Mørk, Jesper

    2000-01-01

    A theoretical analysis of the small-signal frequency response (SSFR) of a wavelength converter based on cross-gain modulation in a semiconductor optical amplifier with a finite waveguide loss is presented. We use a transfer function formalism to explain the resonant behavior of the frequency...... response. The limitations to the magnitude of the spectral overshoot are also accounted for. Operating with the data and CW signals in a co-propagating configuration, we End that the resonance only exists for a finite waveguide loss. In a counter-propagating scheme, a resonance can exist regardless...

  1. Self-field effects on small-signal gain in two-stage free-electron lasers

    Indian Academy of Sciences (India)

    Self-field effects, induced by charge and current densities of the electron beam, on gain in two-stage free-electron laser with nonuniform guide magnetic field is presented. The gain equation for small-signal has been derived analytically. The results of numerical calculations show a gain decrement for group I orbits and a ...

  2. RFID Technology for Continuous Monitoring of Physiological Signals in Small Animals.

    Science.gov (United States)

    Volk, Tobias; Gorbey, Stefan; Bhattacharyya, Mayukh; Gruenwald, Waldemar; Lemmer, Björn; Reindl, Leonhard M; Stieglitz, Thomas; Jansen, Dirk

    2015-02-01

    Telemetry systems enable researchers to continuously monitor physiological signals in unrestrained, freely moving small rodents. Drawbacks of common systems are limited operation time, the need to house the animals separately, and the necessity of a stable communication link. Furthermore, the costs of the typically proprietary telemetry systems reduce the acceptance. The aim of this paper is to introduce a low-cost telemetry system based on common radio frequency identification technology optimized for battery-independent operational time, good reusability, and flexibility. The presented implant is equipped with sensors to measure electrocardiogram, arterial blood pressure, and body temperature. The biological signals are transmitted as digital data streams. The device is able of monitoring several freely moving animals housed in groups with a single reader station. The modular concept of the system significantly reduces the costs to monitor multiple physiological functions and refining procedures in preclinical research.

  3. Weak wide-band signal detection method based on small-scale periodic state of Duffing oscillator

    Science.gov (United States)

    Hou, Jian; Yan, Xiao-peng; Li, Ping; Hao, Xin-hong

    2018-03-01

    The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillatorʼs phase trajectory in a small-scale periodic state are analyzed by introducing the theory of stopping oscillation system. Based on this approach, a novel Duffing oscillator weak wide-band signal detection method is proposed. In this novel method, the reference signal is discarded, and the to-be-detected signal is directly used as a driving force. By calculating the cosine function of a phase space angle, a single Duffing oscillator can be used for weak wide-band signal detection instead of an array of uncoupled Duffing oscillators. Simulation results indicate that, compared with the conventional Duffing oscillator detection method, this approach performs better in frequency detection intervals, and reduces the signal-to-noise ratio detection threshold, while improving the real-time performance of the system. Project supported by the National Natural Science Foundation of China (Grant No. 61673066).

  4. Small-Signal Modeling and Analysis of Grid-Connected Inverter with Power Differential Droop Control

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2016-01-01

    Full Text Available The conventional voltage and frequency droop control strategy in grid-connected inverter suffers a major setback in the presence of disturbance by producing oscillations. Adding a power differential term in droop controller is an effective way to address such drawback. In this paper, grid-connected inverter’s small-signal models of the conventional droop control and the power differential droop control are established. The eigenvalues of the models are then determined by system matrix. The eigenvalues analysis is presented which helps in identifying the relationship between the system stability and controller parameters. It is concluded that the damping ratio of dominant low-frequency eigenvalues increased and the oscillation caused by the disturbance is suppressed when a power differential term is added to the droop control method. The MATLAB/Simulink models of grid-connected inverter with both control strategies are also established to validate the results of small-signal analysis.

  5. Approaches for cytogenetic and molecular analyses of small flow-sorted cell populations from childhood leukemia bone marrow samples

    DEFF Research Database (Denmark)

    Obro, Nina Friesgaard; Madsen, Hans O.; Ryder, Lars Peter

    2011-01-01

    defined cell populations with subsequent analyses of leukemia-associated cytogenetic and molecular marker. The approaches described here optimize the use of the same tube of unfixed, antibody-stained BM cells for flow-sorting of small cell populations and subsequent exploratory FISH and PCR-based analyses....

  6. DFIG turbine representation for small signal voltage control studies

    DEFF Research Database (Denmark)

    Garcia, Jorge Martinez; Kjær, Philip Carne; Teodorescu, Remus

    2010-01-01

    This paper addresses the representation of a wind power plant, based on wound rotor asynchronous generators, with a centralized voltage controller, by an equivalent transfer function, valid for small signal voltage control studies. This representation allows to investigate the influence...... introduced recently by several grid codes from around the world, making important to analyze this control when applied to wind power plants. The performance of the equivalent transfer function has been evaluated and compared using an equivalent grid with different short circuit ratios and active power...... of the centralized plant control gain and short circuit ratio on the system stability, for instance, by analyzing the zero-pole placement. Larger percentages of wind power penetration translate to more demanding requirements coming from the grid codes, for example voltage support at the point of connection has been...

  7. Analyses of GPR signals for characterization of ground conditions in urban areas

    Science.gov (United States)

    Hong, Won-Taek; Kang, Seonghun; Lee, Sung Jin; Lee, Jong-Sub

    2018-05-01

    Ground penetrating radar (GPR) is applied for the characterization of the ground conditions in urban areas. In addition, time domain reflectometry (TDR) and dynamic cone penetrometer (DCP) tests are conducted for the accurate analyses of the GPR images. The GPR images are acquired near a ground excavation site, where a ground subsidence occurred and was repaired. Moreover, the relative permittivity and dynamic cone penetration index (DCPI) are profiled through the TDR and DCP tests, respectively. As the ground in the urban area is kept under a low-moisture condition, the relative permittivity, which is inversely related to the electromagnetic impedance, is mainly affected by the dry density and is inversely proportional to the DCPI value. Because the first strong signal in the GPR image is shifted 180° from the emitted signal, the polarity of the electromagnetic wave reflected at the dense layer, where the reflection coefficient is negative, is identical to that of the first strong signal. The temporal-scaled GPR images can be accurately converted into the spatial-scaled GPR images using the relative permittivity determined by the TDR test. The distribution of the loose layer can be accurately estimated by using the spatial-scaled GPR images and reflection characteristics of the electromagnetic wave. Note that the loose layer distribution estimated in this study matches well with the DCPI profile and is visually verified from the endoscopic images. This study demonstrates that the GPR survey complemented by the TDR and DCP tests, may be an effective method for the characterization of ground conditions in an urban area.

  8. On Small-Signal Stability of Wind Power System with Full-Load Converter Interfaced Wind Turbines

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Akhmatov, Vladislav; Nielsen, Jørgen Nygård

    2010-01-01

    the impact of full-load converter interfaced wind turbines on power system small-signal stability. The study is based on a 7 generator network with lightly damped inter-area modes. A detailed wind turbine model with all grid relevant control functions is used in the study. Furthermore is the wind power plant......Small-signal stability analysis of power system oscillations is a well established field within power system analysis, but not much attention has yet been paid to systems with a high penetration of wind turbines and with large wind power plants. In this paper an analysis is presented which assess...... (WPP) equipped with a WPP voltage controller and comparisons are presented. The models of wind turbine and WPP voltage controller are kindly provided by Siemens Wind Power A/S for this work. The study is based on modal analysis which are complemented with simulations on the nonlinear system....

  9. The use of secondary ion mass spectrometry in forensic analyses of ultra-small samples

    Science.gov (United States)

    Cliff, John

    2010-05-01

    It is becoming increasingly important in forensic science to perform chemical and isotopic analyses on very small sample sizes. Moreover, in some instances the signature of interest may be incorporated in a vast background making analyses impossible by bulk methods. Recent advances in instrumentation make secondary ion mass spectrometry (SIMS) a powerful tool to apply to these problems. As an introduction, we present three types of forensic analyses in which SIMS may be useful. The causal organism of anthrax (Bacillus anthracis) chelates Ca and other metals during spore formation. Thus, the spores contain a trace element signature related to the growth medium that produced the organisms. Although other techniques have been shown to be useful in analyzing these signatures, the sample size requirements are generally relatively large. We have shown that time of flight SIMS (TOF-SIMS) combined with multivariate analysis, can clearly separate Bacillus sp. cultures prepared in different growth media using analytical spot sizes containing approximately one nanogram of spores. An important emerging field in forensic analysis is that of provenance of fecal pollution. The strategy of choice for these analyses-developing host-specific nucleic acid probes-has met with considerable difficulty due to lack of specificity of the probes. One potentially fruitful strategy is to combine in situ nucleic acid probing with high precision isotopic analyses. Bulk analyses of human and bovine fecal bacteria, for example, indicate a relative difference in d13C content of about 4 per mil. We have shown that sample sizes of several nanograms can be analyzed with the IMS 1280 with precisions capable of separating two per mil differences in d13C. The NanoSIMS 50 is capable of much better spatial resolution than the IMS 1280, albeit at a cost of analytical precision. Nevertheless we have documented precision capable of separating five per mil differences in d13C using analytical spots containing

  10. Signal and data processing of small targets 1991; Proceedings of the Meeting, Orlando, FL, Apr. 1-3, 1991

    Science.gov (United States)

    Drummond, Oliver E.

    Attention is given to signal processing; track-before-detect; systems and simulations; association and filtering in tracking; and data processing. Particular attention is given to a linear modeling algorithm for tracking time-varying signals, an optoelectric Gabor detector for transient signals, small-target acquisition and typing by AASAP, model-based analysis of 3D spatial-temporal IR clutter suppression filtering, algorithms and architectures for implementing large-velocity filter banks, an end-to-end scenario-generating model for IRST performance analysis, detection and tracking of small targets in persistence, an incremental model for target maneuver estimation, implementation of an angle-only tracking filter, a global modeling approach for multisensor problems, passive-sensor data fusion, midcourse multitarget racking using continuous representation, neural data association, and statistical initial orbit determination. (For individual items see A93-26797 to A93-26799)

  11. Break spectrum analyses for small break loss of coolant accidents in a RESAR-3S Plant

    International Nuclear Information System (INIS)

    Fletcher, C.D.; Kullberg, C.M.

    1986-03-01

    A series of thermal-hydraulic analyses were performed to investigate phenomena occurring during small break loss-of-coolant-accident (LOCA) sequences in a RESAR-3S pressurized water reactor. The analysis included simulations of plant behavior using the TRAC-PF1 and RELAP5/MOD2 computer codes. Series of calculations were performed using both codes for different break sizes. The analyses presented here also served an audit function in that the results shown here were used by the US Nuclear Regulatory Commission (NRC) as an independent confirmation of similar analyses performed by Westinghouse Electric Company using another computer code. 10 refs., 62 figs., 14 tabs

  12. Current collapse modeling in AlGaN/GaN HEMT using small signal equivalent circuit for high power application

    Science.gov (United States)

    Nirmal, D.; Arivazhagan, L.; Fletcher, A. S. Augustine; Ajayan, J.; Prajoon, P.

    2018-01-01

    In this paper, the drain current collapse in AlGaN/GaN High Electron Mobility Transistor (HEMT) with field plate engineering is investigated. A small signal equivalent circuit of AlGaN/GaN HEMT is developed and a new drain current model is derived. This model is useful to correlate the impact of intrinsic capacitance and conductance on drain current collapse. The proposed device suppressed the current collapse phenomena by 10% compared with the conventional AlGaN/GaN HEMT. Moreover, the DC characteristics of the simulated device shows a drain current of 900 mA/mm, breakdown voltage of 291 V and transconductance of 175 mS/mm. Besides, the intrinsic capacitance and conductance parameters are extracted and its impact on drain current is analysed. Finally, the simulation results obtained were in compliance with the derived mathematical model of AlGaN/GaN HEMT.

  13. Towards a time-domain modeling framework for small-signal analysis of unbalanced microgrids

    OpenAIRE

    Ojo, Y; Schiffer, JF

    2017-01-01

    Small-signal analysis is one of the most frequently used techniques to assess the operating conditions of power systems. Typically, this analysis is conducted by employing a phasor-based model of the power network derived under the assumption of balanced operating conditions. However, distribution networks and, amongst these, microgrids are often unbalanced. Hence, their analysis requires the development of tools and methods valid under such conditions. Motivated by this, we propose a modelin...

  14. A PSP-based small-signal MOSFET model for both quasi-static and nonquasi-static operations

    NARCIS (Netherlands)

    Aarts, A.C.T.; Smit, G.D.J.; Scholten, A.J.; Klaassen, D.B.M.

    2008-01-01

    In this paper, a small-signal MOSFET model is described, which takes the local effects of both velocity saturation and transverse mobility reduction into account. The model is based on the PSP model and is valid for both quasi-static and nonquasi-static (NQS) operations. Recently, it has been found

  15. Best Signal Quality in Cellular Networks: Asymptotic Properties and Applications to Mobility Management in Small Cell Networks

    Directory of Open Access Journals (Sweden)

    Baccelli François

    2010-01-01

    Full Text Available The quickly increasing data traffic and the user demand for a full coverage of mobile services anywhere and anytime are leading mobile networking into a future of small cell networks. However, due to the high-density and randomness of small cell networks, there are several technical challenges. In this paper, we investigate two critical issues: best signal quality and mobility management. Under the assumptions that base stations are uniformly distributed in a ring-shaped region and that shadowings are lognormal, independent, and identically distributed, we prove that when the number of sites in the ring tends to infinity, then (i the maximum signal strength received at the center of the ring tends in distribution to a Gumbel distribution when properly renormalized, and (ii it is asymptotically independent of the interference. Using these properties, we derive the distribution of the best signal quality. Furthermore, an optimized random cell scanning scheme is proposed, based on the evaluation of the optimal number of sites to be scanned for maximizing the user data throughput.

  16. Using reservoir-engineering to convert a coherent signal in optomechanics with small optomechanical cooperativity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tao, E-mail: suiyueqiaoqiao@163.com [Key Lab of Coherent Light, Atomic and Molecular Spectroscopy, Ministry of Education, and College of Physics, Jilin University, Changchun 130012 (China); College of Physics, Tonghua Normal University, Tonghua 134000 (China); Wang, Tie [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Fu, Changbao [College of Physics, Tonghua Normal University, Tonghua 134000 (China); Su, Xuemei, E-mail: suxm@jlu.edu.cn [Key Lab of Coherent Light, Atomic and Molecular Spectroscopy, Ministry of Education, and College of Physics, Jilin University, Changchun 130012 (China)

    2017-05-10

    Optomechanical dark mode plays a central role in effective mechanically-mediated conversion of two different cavity fields. In this paper, we present a more efficient method to utilize the dark mode to transfer a coherent signal. When an auxiliary cavity mode is exploited, two approaches are proposed to effectively eliminate the optomechanical bright mode, and only the optomechanical dark mode is left to facilitate state transfer. Even with small cooperativity and different losses for the two target modes, the internal cavity mode-conversion efficiency can also reach unity. - Highlights: • Reservoir-engineering is used for state conversion. • The optomechanical bright mode can be absolutely eliminated. • Small cooperativity and different losses are feasible for ideal conversion efficiency.

  17. Dynamic strain analysis of structures employing digital signal processing, storage and display

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, P K; Misra, V M; Kumar, Surendra

    1975-01-01

    A multi-channel digital technique has been adopted for analysing wave patterns of stresses and strains in structures, particularly under dynamic conditions. This technique provides adequate signal to noise discrimination and high sensitivity for very small (few milli-volts) and slow varying signals (few Hz to 100 Hz.), and A-D conversion accompined by live display during the course of data gathering and computer compatible output. This system also provides fast response because of inherent 50 MHz digitising speed and a large dynamic range of 1024 discrete signal steps. The signals can be suitably fed to the A-D converter (50 MHz) or can be analysed employing frequency modulation techniques and time mode operation of the analyser. The data can be gathered in the field on cassette tapes and replayed in the laboratory for detailed analysis. This technique would provide a versatile system for dynamic analysis of structures under varying conditions. e.g. structures in nuclear power systems, such as testing of end fittings, calandria, vibration testing and measurements exploying pressure transducers.

  18. Dynamic strain analysis of structures employing digital signal processing, storage and display

    International Nuclear Information System (INIS)

    Patwardhan, P.K.; Misra, V.M.; Kumar, Surendra

    1975-01-01

    A multi-channel digital technique has been adopted for analysing wave patterns of stresses and strains in structures, particularly under dynamic conditions. This technique provides adequate signal to noise discrimination and high sensitivity for very small (few milli-volts) and slow varying signals (few Hz to 100 Hz.), A-D conversion accompined by live display during the course of data gathering and computer compatible output. This system also provides fast response because of inherent 50 MHz digitising speed and a large dynamic range of 1024 discrete signal steps. The signals can be suitably fed to the A-D converter (50 MHz) or can be analysed employing frequency modulation techniques and time mode operation of the analyser. The data can be gathered in the field on cassette tapes and replayed in the laboratory for detailed analysis. This technique would provide a versatile system for dynamic analysis of structures under varying conditions. e.g. structures in nuclear power systems, such as testing of end fittings, calandria, vibration testing and measurements exploying pressure transducers. (author)

  19. Analysing conflicts around small-scale gold mining in the Amazon : The contribution of a multi-temporal model

    NARCIS (Netherlands)

    Salman, Ton; de Theije, Marjo

    Conflict is small-scale gold mining's middle name. In only a very few situations do mining operations take place without some sort of conflict accompanying the activity, and often various conflicting stakeholders struggle for their interests simultaneously. Analyses of such conflicts are typically

  20. FEL small signal gain reduction due to phase error of undulator

    International Nuclear Information System (INIS)

    Jia Qika

    2002-01-01

    The effects of undulator phase errors on the Free Electron Laser small signal gain is analyzed and discussed. The gain reduction factor due to the phase error is given analytically for low-gain regimes, it shows that degradation of the gain is similar to that of the spontaneous radiation, has a simple exponential relation with square of the rms phase error, and the linear variation part of phase error induces the position shift of maximum gain. The result also shows that the Madey's theorem still hold in the presence of phase error. The gain reduction factor due to the phase error for high-gain regimes also can be given in a simple way

  1. Applicability of two mobile analysers for mercury in urine in small-scale gold mining areas.

    Science.gov (United States)

    Baeuml, Jennifer; Bose-O'Reilly, Stephan; Lettmeier, Beate; Maydl, Alexandra; Messerer, Katalin; Roider, Gabriele; Drasch, Gustav; Siebert, Uwe

    2011-12-01

    Mercury is still used in developing countries to extract gold from the ore in small-scale gold mining areas. This is a major health hazard for people living in mining areas. The concentration of mercury in urine was analysed in different mining areas in Zimbabwe, Indonesia and Tanzania. First the urine samples were analysed by CV-AAS (cold vapour atomic absorption spectrometry) during the field projects with a mobile mercury analyser (Lumex(®) or Seefelder(®)) and secondly, in a laboratory with a stationary CV-AAS mercury analyser (PerkinElmer(®)). Caused by the different systems (reduction agent either SnCl(2) (Lumex(®) or Seefelder(®))) or NaBH(4) (PerkinElmer(®)), with the mobile analysers only the inorganic mercury was obtained and with the stationary system the total mercury concentration was measured. The aims of the study were whether the results obtained in field with the mobile equipments can be compared with the stationary reference method in the laboratory and allow the application of these mobile analysers in screening studies on concerned populations to select those, who are exposed to critical mercury levels. Overall, the concentrations obtained with the two mobile systems were approximately 25% lower than determined with the stationary system. Nevertheless, both mobile systems seem to be very useful for screening of volunteers in field. Moreover, regional staff may be trained on such analysers to perform screening tests by themselves. Copyright © 2011 Elsevier GmbH. All rights reserved.

  2. Small-Signal Modeling of the PVR-Based AD Scheme and Controller Design for Three-Phase Standalone DG System

    DEFF Research Database (Denmark)

    Shen, Pan; Han, Yang; Lu, Chang

    2016-01-01

    This paper presents the small-signal state-space modeling and a new multifunctional multi-loop control strategy for three-phase inverter-based islanded DG systems under unbalanced and/or nonlinear load conditions. The proposed control methodology utilizes the parallel virtual resistance (PVR...... controllers are based on an enhanced proportional resonant (PR) structure to achieve zero steady-state error, and multi-resonant harmonic compensator (MRHC) plus PR controller to prevent low-order load current harmonics to distort the output voltage. The proposed small-signal model of the islanded DG system...... with multi-loop control strategy in the stationary reference frame is presented. Moreover, an enhanced delay compensation (EDC) scheme based on two integrators of the discrete PR controller is presented to improve stability margins with a higher accuracy compared with the existing methods. Then, a detailed...

  3. A summary of impacts of wind power integration on power system small-signal stability

    Science.gov (United States)

    Yan, Lei; Wang, Kewen

    2017-05-01

    Wind power has been increasingly integrated into power systems over the last few decades because of the global energy crisis and the pressure on environmental protection, and the stability of the system connected with wind power is becoming more prominent. This paper summaries the research status, achievements as well as deficiencies of the research on the impact of wind power integration on power system small-signal stability. In the end, the further research needed are discussed.

  4. PI3K-AKT signaling pathway is involved in hypoxia/thermal-induced immunosuppression of small abalone Haliotis diversicolor.

    Science.gov (United States)

    Sun, Yulong; Zhang, Xin; Wang, Guodong; Lin, Shi; Zeng, Xinyang; Wang, Yilei; Zhang, Ziping

    2016-12-01

    The PI3K-AKT signal pathway has been found to be involved in many important physiological and pathological processes of the innate immune system of vertebrates and invertebrates. In this study, the AKT (HdAKT) and PI3K (HdPI3K) gene of small abalone Haliotis diversicolor were cloned and characterized for the important status of PI3K and AKT protein in PI3K-AKT signaling pathway. The full length cDNAs of HdAKT and HdPI3K are 2126 bp and 6052 bp respectively, encoding proteins of 479 amino acids and 1097 amino acids, respectively. The mRNA expression level of fourteen genes in the PI3K-AKT signaling pathway were detected by quantitative real-time PCR. The results showed that all these fourteen genes were ubiquitously expressed in seven selected tissues. Meanwhile, HdAKT was expressed in haemocytes with the highest expression level (p abalone. The mRNA expression of these genes in gills, haemocytes and hepatopancreas was significantly down-regulated after the Vibrio parahaemolyticus stimulation with environment stimulation (thermal, hypoxia and thermal & hypoxia). These results indicate that the dual/multiple stresses defeat the immune system and lead to immunosuppression in abalone. PI3K-AKT signaling pathway may be involved in hypoxia/thermal-induced immunosuppression of small abalone Haliotis diversicolor. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Structure analyses of swollen rubber-filler systems by using contrast variation Small angle neutron scattering (SANS)

    International Nuclear Information System (INIS)

    Takenaka, Mikihito; Nishitsuji, Shotaro; Yamaguchi, Daisuke; Koizumi, Satoshi

    2009-01-01

    Full text: The polymer layers absorbed on silica particles in rubber-silica systems have investigated with contrast variation small-angle neutron scattering (SANS) method. The scattering intensities of specimens swollen by the solvents having various scattering length densities were measured. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer-polymer correlation SPP(q), the scattering function for silica- silica correlation SSS(q), and the scattering function for polymer- silica correlation SPS(q). The analyses of SSS(q) explored the hierarchical structures formed by silica particles. The analyses of SPS(q) and SSS(q) clarified the existence of dense polymer layers around silica aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, the volume fractions of polymer of layers and matrix, and the correlation length of the matrix network. The contrast variation SANS is found to be a powerful tool of the analyses of the structures of the rubber-filler systems. (author)

  6. Parametric and Wavelet Analyses of Acoustic Emission Signals for the Identification of Failure Modes in CFRP Composites Using PZT and PVDF Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Prasopchaichana, Kritsada; Kwon, Oh Yang [Inha University, Incheon (Korea, Republic of)

    2007-12-15

    Combination of the parametric and the wavelet analyses of acoustic emission (AE) signals was applied to identify the failure modes in carbon fiber reinforced plastic (CFRP) composite laminates during tensile testing. AE signals detected by surface mounted lead-zirconate-titanate (PZT) and polyvinylidene fluoride (PVDF) sensors were analyzed by parametric analysis based on the time of occurrence which classifies AE signals corresponding to failure modes. The frequency band level-energy analysis can distinguish the dominant frequency band for each failure mode. It was observed that the same type of failure mechanism produced signals with different characteristics depending on the stacking sequences and the type of sensors. This indicates that the proposed method can identify the failure modes of the signals if the stacking sequences and the sensors used are known

  7. A small animal PET based on GAPDs and charge signal transmission approach for hybrid PET-MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jihoon; Choi, Yong; Hong, Key Jo; Hu, Wei; Jung, Jin Ho; Huh, Yoonsuk [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kim, Byung-Tae, E-mail: ychoi.image@gmail.com [Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of)

    2011-08-15

    Positron emission tomography (PET) employing Geiger-mode avalanche photodiodes (GAPDs) and charge signal transmission approach was developed for small animal imaging. Animal PET contained 16 LYSO and GAPD detector modules that were arranged in a 70 mm diameter ring with an axial field of view of 13 mm. The GAPDs charge output signals were transmitted to a preamplifier located remotely using 300 cm flexible flat cables. The position decoder circuits (PDCs) were used to multiplex the PET signals from 256 to 4 channels. The outputs of the PDCs were digitized and further-processed in the data acquisition unit. The cross-compatibilities of the PET detectors and MRI were assessed outside and inside the MRI. Experimental studies of the developed full ring PET were performed to examine the spatial resolution and sensitivity. Phantom and mouse images were acquired to examine the imaging performance. The mean energy and time resolution of the PET detector were 17.6% and 1.5 ns, respectively. No obvious degradation on PET and MRI was observed during simultaneous PET-MRI data acquisition. The measured spatial resolution and sensitivity at the CFOV were 2.8 mm and 0.7%, respectively. In addition, a 3 mm diameter line source was clearly resolved in the hot-sphere phantom images. The reconstructed transaxial PET images of the mouse brain and tumor displaying the glucose metabolism patterns were imaged well. These results demonstrate GAPD and the charge signal transmission approach can allow the development of high performance small animal PET with improved MR compatibility.

  8. Real-time remedial action against aperiodic small signal rotor angle instability

    DEFF Research Database (Denmark)

    Weckesser, Johannes Tilman Gabriel; Jóhannsson, Hjörtur; Østergaard, Jacob

    2016-01-01

    This paper presents a method that in real-time determines remedial actions, which restore stable operation with respect to aperiodic small signal rotor angle stability (ASSRAS) when insecure or unstable operation has been detected. An ASSRAS assessment method is used to monitor the stability...... impedance plane to determine an active power redispatch among selected generators to restore stable and secure operation. Since the method is purely based on analytically derived expression, the computation of the remedial actions is fast and well suited for real-time operation. The method was tested...... boundary for each generator in real-time. The ASSRAS boundary represents the condition when a generator reaches the maximum steady state active power injection. The proposed control method exploits analytically derived expressions for the ASSRAS boundary and other characteristic curves in the injection...

  9. Biomedical application of MALDI mass spectrometry for small-molecule analysis.

    Science.gov (United States)

    van Kampen, Jeroen J A; Burgers, Peter C; de Groot, Ronald; Gruters, Rob A; Luider, Theo M

    2011-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is an emerging analytical tool for the analysis of molecules with molar masses below 1,000 Da; that is, small molecules. This technique offers rapid analysis, high sensitivity, low sample consumption, a relative high tolerance towards salts and buffers, and the possibility to store sample on the target plate. The successful application of the technique is, however, hampered by low molecular weight (LMW) matrix-derived interference signals and by poor reproducibility of signal intensities during quantitative analyses. In this review, we focus on the biomedical application of MALDI-MS for the analysis of small molecules and discuss its favorable properties and its challenges as well as strategies to improve the performance of the technique. Furthermore, practical aspects and applications are presented. © 2010 Wiley Periodicals, Inc.

  10. Small-Signal Analysis of the Microgrid Secondary Control Considering a Communication Time Delay

    DEFF Research Database (Denmark)

    Coelho, Ernane Antônio Alves; Wu, Dan; Guerrero, Josep M.

    2016-01-01

    This paper presents a small-signal analysis of an islanded microgrid composed of two or more voltage-source inverters connected in parallel. The primary control of each inverter is integrated through an internal current and voltage loops using proportional resonant compensators, a virtual impedance......, and an external power controller based on frequency and voltage droops. The frequency restoration function is implemented at the secondary control level, which executes a consensus algorithm that consists of a load-frequency control and a single time delay communication network. The consensus network consists...... the behavior of the system considering control parameters and time delay variation....

  11. Observation of small sub-pulses out of the delayed-interference signal-wavelength converter

    DEFF Research Database (Denmark)

    Sakaguchi, J.; Nielsen, Mads Lønstrup; Ohira, T.

    2005-01-01

    The generation of small sub-pulses in the delayed-interference signal-wavelength converter (DISC), which has been studied for use in future 160-Gb/s optical time division multiplexing-wavelength division multiplexing (OTDM-WDM) communication systems, was recently predicted as a potential problem....... In this work, we have experimentally verified the generation of such pulses and its mechanism. In the experiments we used 3.8-ps-long 1.56-mu m input pulses with repetition frequencies from 12.5 to 25.0 GHz and a cross-correlation monitoring system with a time resolution of approximately 2 ps....

  12. Signal and data processing of small targets 1992; Proceedings of the Meeting, Orlando, FL, Apr. 20-22, 1992

    Science.gov (United States)

    Drummond, Oliver E.

    This volume on signal and data processing of small targets contains chapters devoted to signal processing, low observable detection, systems and simulations, association and filtering in tracking, multiple sensor processing and fusion, and data processing. Papers included are on multisensor predetection fusion, adaptive whitening filters for small target detection, unified framework for IR target detection and tracking, and target detection from image sequences using pixel-based decision criterion. Attention is also given to automatic acquisition and tracking of rounds and targets for electrooptic fire control, advanced surveillance testbed and background modeling, an interacting-multiple-model algorithm for tracking targets that maneuver through coordinated turns, and angular momentum and ballistic tracking. Other papers are on a data integration (fusion) tree paradigm, single-scan tracking using N IR sensors, and track monitoring with single and multiple 2D passive sensors. (No individual items are abstracted in this volume)

  13. Development of Optical Molecular Imaging System for the Acquisition of Bioluminescence Signals from Small Animals

    International Nuclear Information System (INIS)

    Lee, Byeong Il; Kim, Hyeon Sik; Jeong, Hye Jin; Lee, Hyung Jae; Moon, Seung Min; Kwon, Seung Young; Jeong, Shin Young; Bom, Hee Seung; Min, Jung Joon; Choi, Eun Seo

    2009-01-01

    Optical imaging is providing great advance and improvement in genetic and molecular imaging of animals and humans. Optical imaging system consists of optical imaging devices, which carry out major function for monitoring, tracing, and imaging in most of molecular in-vivo researches. In bio-luminescent imaging, small animals containing luciferase gene locally irradiate light, and emitted photons transmitted through skin of the small animals are imaged by using a high sensitive charged coupled device (CCD) camera. In this paper, we introduced optical imaging system for the image acquisition of bio-luminescent signals emitted from small animals. In the system, Nikon lens and four LED light sources were mounted at the inside of a dark box. A cooled CCD camera equipped with a control module was used. We tested the performance of the optical imaging system using effendorf tube and light emitting bacteria which injected intravenously into CT26 tumor bearing nude mouse. The performance of implemented optical imaging system for bio-luminescence imaging was demonstrated and the feasibility of the system in small animal imaging application was proved. We anticipate this system could be a useful tool for the molecular imaging of small animals adaptable for various experimental conditions in future

  14. Mitigating high ‘equity capital’ risk exposure to ‘small cap’ sector in India: analysing ‘key factors of success’ for ‘Institutional Investors’ whilst Investing in small cap sector in India

    OpenAIRE

    Narang, Anish

    2014-01-01

    This paper deals with the subject of mitigating high ‘Equity Capital’ Risk Exposure to ‘Small Cap’ Sector in India. Institutional investors in India are prone to be risk averse when it comes to investing in the small cap sector in India as they find the companies risky and volatile. This paper will help analyse ‘Key Factors of success’ for ‘Institutional Investors’ whilst investing in Small Cap sector in India as some of these Indian small cap stocks offer handsome returns despite economic do...

  15. Small-signal analysis and particle-in-cell simulations of planar dielectric Cherenkov masers for use as high-frequency, moderate-power broadband amplifiers

    International Nuclear Information System (INIS)

    Carlsten, Bruce E.

    2002-01-01

    A small-signal gain analysis of the planar dielectric Cherenkov maser is presented. The analysis results in a Pierce gain solution, with three traveling-wave modes. The analysis shows that the dielectric Cherenkov maser has a remarkable broadband tuning ability near cutoff, while maintaining reasonable gain rates. Numerical simulations verifying the small-signal gain results are presented, using a particle-in-cell code adapted specifically for planar traveling-wave tubes. An instantaneous bandwidth is numerically shown to be very large, and saturated efficiency for a nominal high-power design is shown to be in the range of standard untapered traveling-wave tubes

  16. ANALYSIS OF MONTE CARLO SIMULATION SAMPLING TECHNIQUES ON SMALL SIGNAL STABILITY OF WIND GENERATOR- CONNECTED POWER SYSTEM

    Directory of Open Access Journals (Sweden)

    TEMITOPE RAPHAEL AYODELE

    2016-04-01

    Full Text Available Monte Carlo simulation using Simple Random Sampling (SRS technique is popularly known for its ability to handle complex uncertainty problems. However, to produce a reasonable result, it requires huge sample size. This makes it to be computationally expensive, time consuming and unfit for online power system applications. In this article, the performance of Latin Hypercube Sampling (LHS technique is explored and compared with SRS in term of accuracy, robustness and speed for small signal stability application in a wind generator-connected power system. The analysis is performed using probabilistic techniques via eigenvalue analysis on two standard networks (Single Machine Infinite Bus and IEEE 16–machine 68 bus test system. The accuracy of the two sampling techniques is determined by comparing their different sample sizes with the IDEAL (conventional. The robustness is determined based on a significant variance reduction when the experiment is repeated 100 times with different sample sizes using the two sampling techniques in turn. Some of the results show that sample sizes generated from LHS for small signal stability application produces the same result as that of the IDEAL values starting from 100 sample size. This shows that about 100 sample size of random variable generated using LHS method is good enough to produce reasonable results for practical purpose in small signal stability application. It is also revealed that LHS has the least variance when the experiment is repeated 100 times compared to SRS techniques. This signifies the robustness of LHS over that of SRS techniques. 100 sample size of LHS produces the same result as that of the conventional method consisting of 50000 sample size. The reduced sample size required by LHS gives it computational speed advantage (about six times over the conventional method.

  17. High throughput screening for small molecule enhancers of the interferon signaling pathway to drive next-generation antiviral drug discovery.

    Directory of Open Access Journals (Sweden)

    Dhara A Patel

    Full Text Available Most of current strategies for antiviral therapeutics target the virus specifically and directly, but an alternative approach to drug discovery might be to enhance the immune response to a broad range of viruses. Based on clinical observation in humans and successful genetic strategies in experimental models, we reasoned that an improved interferon (IFN signaling system might better protect against viral infection. Here we aimed to identify small molecular weight compounds that might mimic this beneficial effect and improve antiviral defense. Accordingly, we developed a cell-based high-throughput screening (HTS assay to identify small molecules that enhance the IFN signaling pathway components. The assay is based on a phenotypic screen for increased IFN-stimulated response element (ISRE activity in a fully automated and robust format (Z'>0.7. Application of this assay system to a library of 2240 compounds (including 2160 already approved or approvable drugs led to the identification of 64 compounds with significant ISRE activity. From these, we chose the anthracycline antibiotic, idarubicin, for further validation and mechanism based on activity in the sub-µM range. We found that idarubicin action to increase ISRE activity was manifest by other members of this drug class and was independent of cytotoxic or topoisomerase inhibitory effects as well as endogenous IFN signaling or production. We also observed that this compound conferred a consequent increase in IFN-stimulated gene (ISG expression and a significant antiviral effect using a similar dose-range in a cell-culture system inoculated with encephalomyocarditis virus (EMCV. The antiviral effect was also found at compound concentrations below the ones observed for cytotoxicity. Taken together, our results provide proof of concept for using activators of components of the IFN signaling pathway to improve IFN efficacy and antiviral immune defense as well as a validated HTS approach to identify

  18. Discovering Small Molecule Inhibitors Targeted to Ligand-Stimulated RAGE-DIAPH1 Signaling Transduction

    Science.gov (United States)

    Pan, Jinhong

    The receptor of advanced glycation end product (RAGE) is a multiligand receptor of the immunoglobulin superfamily of cell surface molecules, which plays an important role in immune responses. Full-length RAGE includes three extracellular immunoglobulin domains, a transmembrane domain and an intracellular domain. It is a pattern recognition receptor that can bind diverse ligands. NMR spectroscopy and x-ray crystallization studies of the extracellular domains of RAGE indicate that RAGE ligands bind by distinct charge- and hydrophobicity-dependent mechanisms. It is found that calgranulin binding to the C1C2 domain or AGEs binding to the V domain activates extracellular signaling, which triggers interactions of the RAGE cytoplasmic tail (ctRAGE) with intracellular effector, such as diaphanous 1 (DIAPH1), to initiate signal transduction cascades. ctRAGE is essential for RAGE-ligand-mediated signal transduction and consequent modulation of gene expression and cellular properties. RAGE is over-expressed in diseased tissues of most RAGE-associated pathogenic conditions, such as complications of Alzheimer's diseases, diabetes, vascular diseases, inflammation, cancers and neurodegeneration. They are the major diseases affecting a large population worldwide. RAGE can function as a biomarker or drug target for these diseases. The cytoplasmic tail of RAGE can be used as a drug target to inhibit RAGE-induced intracellular signaling by small molecule inhibitors to treat RAGE-associated diseases. We developed a high throughput screening assay with which we probed a small molecule library of 58,000 compounds to find that 777 small molecules displayed 50% inhibition and 97 compounds demonstrated dose-dependent inhibition of the binding of ctRAGE-DIAPH1. Eventually, there were 13 compounds which displayed dose-dependent inhibition of ctRAGE binding to DIAPH1 and direct binding to ctRAGE analyzed by 15N HSQC-NMR and native tryptophan fluorescence titration experiments; thus, they were

  19. The impact of global signal regression on resting state correlations: are anti-correlated networks introduced?

    Science.gov (United States)

    Murphy, Kevin; Birn, Rasmus M; Handwerker, Daniel A; Jones, Tyler B; Bandettini, Peter A

    2009-02-01

    Low-frequency fluctuations in fMRI signal have been used to map several consistent resting state networks in the brain. Using the posterior cingulate cortex as a seed region, functional connectivity analyses have found not only positive correlations in the default mode network but negative correlations in another resting state network related to attentional processes. The interpretation is that the human brain is intrinsically organized into dynamic, anti-correlated functional networks. Global variations of the BOLD signal are often considered nuisance effects and are commonly removed using a general linear model (GLM) technique. This global signal regression method has been shown to introduce negative activation measures in standard fMRI analyses. The topic of this paper is whether such a correction technique could be the cause of anti-correlated resting state networks in functional connectivity analyses. Here we show that, after global signal regression, correlation values to a seed voxel must sum to a negative value. Simulations also show that small phase differences between regions can lead to spurious negative correlation values. A combination breath holding and visual task demonstrates that the relative phase of global and local signals can affect connectivity measures and that, experimentally, global signal regression leads to bell-shaped correlation value distributions, centred on zero. Finally, analyses of negatively correlated networks in resting state data show that global signal regression is most likely the cause of anti-correlations. These results call into question the interpretation of negatively correlated regions in the brain when using global signal regression as an initial processing step.

  20. Preliminary analyses on hydrogen diffusion through small break of thermo-chemical IS process hydrogen plant

    International Nuclear Information System (INIS)

    Somolova, Marketa; Terada, Atsuhiko; Takegami, Hiroaki; Iwatsuki, Jin

    2008-12-01

    Japan Atomic Energy Agency has been conducting a conceptual design study of nuclear hydrogen demonstration plant, that is, a thermal-chemical IS process hydrogen plant coupled with the High temperature Engineering Test Reactor (HTTR-IS), which will be planed to produce a large amount of hydrogen up to 1000m 3 /h. As part of the conceptual design work of the HTTR-IS system, preliminary analyses on small break of a hydrogen pipeline in the IS process hydrogen plant was carried out as a first step of the safety analyses. This report presents analytical results of hydrogen diffusion behaviors predicted with a CFD code, in which a diffusion model focused on the turbulent Schmidt number was incorporated. By modifying diffusion model, especially a constant accompanying the turbulent Schmidt number in the diffusion term, analytical results was made agreed well with the experimental results. (author)

  1. Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

    International Nuclear Information System (INIS)

    Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung; Song, Jie Young; Yun, Yeon Sook

    2009-01-01

    The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently mutated..protein..in cancer cells. Lack of functional p53..is accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference

  2. Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung [PharmacoGenomics Research Center, Inje University, Busan (Korea, Republic of); Song, Jie Young; Yun, Yeon Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2009-05-15

    The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently mutated..protein..in cancer cells. Lack of functional p53..is accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference.

  3. Maturation and integration of adult born hippocampal neurons: signal convergence onto small Rho GTPases

    Directory of Open Access Journals (Sweden)

    Krishna eVadodaria

    2013-08-01

    Full Text Available Adult neurogenesis, restricted to specific regions in the mammalian brain, represents one of the most interesting forms of plasticity in the mature nervous system. Adult-born hippocampal neurons play important roles in certain forms of learning and memory, and altered hippocampal neurogenesis has been associated with a number of neuropsychiatric diseases such as major depression and epilepsy. Newborn neurons go through distinct developmental steps from a dividing neurogenic precursor to a synaptically integrated mature neuron. Previous studies have uncovered several molecular signaling pathways involved in distinct steps of this maturational process. In this context, the small Rho GTPases, Cdc42, Rac1 and RhoA have recently been shown to regulate the morphological and synaptic maturation of adult-born dentate granule cells in vivo. Distinct upstream regulators, including several growth factors that modulate maturation and integration of newborn neurons have been shown to also recruit the small Rho GTPases. Here we review recent findings and highlight the possibility that small Rho GTPases may act as central assimilators, downstream of critical input onto adult-born hippocampal neurons contributing to their maturation and integration into the existing dentate gyrus circuitry.

  4. Analysing 21cm signal with artificial neural network

    Science.gov (United States)

    Shimabukuro, Hayato; a Semelin, Benoit

    2018-05-01

    The 21cm signal at epoch of reionization (EoR) should be observed within next decade. We expect that cosmic 21cm signal at the EoR provides us both cosmological and astrophysical information. In order to extract fruitful information from observation data, we need to develop inversion method. For such a method, we introduce artificial neural network (ANN) which is one of the machine learning techniques. We apply the ANN to inversion problem to constrain astrophysical parameters from 21cm power spectrum. We train the architecture of the neural network with 70 training datasets and apply it to 54 test datasets with different value of parameters. We find that the quality of the parameter reconstruction depends on the sensitivity of the power spectrum to the different parameter sets at a given redshift and also find that the accuracy of reconstruction is improved by increasing the number of given redshifts. We conclude that the ANN is viable inversion method whose main strength is that they require a sparse extrapolation of the parameter space and thus should be usable with full simulation.

  5. Organization of signal flow in directed networks

    International Nuclear Information System (INIS)

    Bányai, M; Bazsó, F; Négyessy, L

    2011-01-01

    Confining an answer to the question of whether and how the coherent operation of network elements is determined by the network structure is the topic of our work. We map the structure of signal flow in directed networks by analysing the degree of edge convergence and the overlap between the in- and output sets of an edge. Definitions of convergence degree and overlap are based on the shortest paths, thus they encapsulate global network properties. Using the defining notions of convergence degree and overlapping set we clarify the meaning of network causality and demonstrate the crucial role of chordless circles. In real-world networks the flow representation distinguishes nodes according to their signal transmitting, processing and control properties. The analysis of real-world networks in terms of flow representation was in accordance with the known functional properties of the network nodes. It is shown that nodes with different signal processing, transmitting and control properties are randomly connected at the global scale, while local connectivity patterns depart from randomness. The grouping of network nodes according to their signal flow properties was unrelated to the network's community structure. We present evidence that the signal flow properties of small-world-like, real-world networks cannot be reconstructed by algorithms used to generate small-world networks. Convergence degree values were calculated for regular oriented trees, and the probability density function for networks grown with the preferential attachment mechanism. For Erdos–Rényi graphs we calculated the probability density function of both convergence degrees and overlaps

  6. Wnt/beta-Catenin Signaling and Small Molecule Inhibitors

    Science.gov (United States)

    Voronkov, Andrey; Krauss, Stefan

    2012-01-01

    Wnt/β-catenin signaling is a branch of a functional network that dates back to the first metazoans and it is involved in a broad range of biological systems including stem cells, embryonic development and adult organs. Deregulation of components involved in Wnt/β-catenin signaling has been implicated in a wide spectrum of diseases including a number of cancers and degenerative diseases. The key mediator of Wnt signaling, β-catenin, serves several cellular functions. It functions in a dynamic mode at multiple cellular locations, including the plasma membrane, where β-catenin contributes to the stabilization of intercellular adhesive complexes, the cytoplasm where β-catenin levels are regulated and the nucleus where β-catenin is involved in transcriptional regulation and chromatin interactions. Central effectors of β-catenin levels are a family of cysteine-rich secreted glycoproteins, known as Wnt morphogens. Through the LRP5/6-Frizzled receptor complex, Wnts regulate the location and activity of the destruction complex and consequently intracellular β- catenin levels. However, β-catenin levels and their effects on transcriptional programs are also influenced by multiple other factors including hypoxia, inflammation, hepatocyte growth factor-mediated signaling, and the cell adhesion molecule E-cadherin. The broad implications of Wnt/β-catenin signaling in development, in the adult body and in disease render the pathway a prime target for pharmacological research and development. The intricate regulation of β-catenin at its various locations provides alternative points for therapeutic interventions. PMID:23016862

  7. Real-time single-molecule co-immunoprecipitation analyses reveal cancer-specific Ras signalling dynamics

    Science.gov (United States)

    Lee, Hong-Won; Kyung, Taeyoon; Yoo, Janghyun; Kim, Tackhoon; Chung, Chaeuk; Ryu, Ji Young; Lee, Hanki; Park, Kihyun; Lee, Sangkyu; Jones, Walton D.; Lim, Dae-Sik; Hyeon, Changbong; Do Heo, Won; Yoon, Tae-Young

    2013-01-01

    Co-immunoprecipitation (co-IP) has become a standard technique, but its protein-band output provides only static, qualitative information about protein–protein interactions. Here we demonstrate a real-time single-molecule co-IP technique that generates real-time videos of individual protein–protein interactions as they occur in unpurified cell extracts. By analysing single Ras–Raf interactions with a 50-ms time resolution, we have observed transient intermediates of the protein–protein interaction and determined all the essential kinetic rates. Using this technique, we have quantified the active fraction of native Ras proteins in xenograft tumours, normal tissue and cancer cell lines. We demonstrate that the oncogenic Ras mutations selectively increase the active-Ras fraction by one order of magnitude, without affecting total Ras levels or single-molecule signalling kinetics. Our approach allows us to probe the previously hidden, dynamic aspects of weak protein–protein interactions. It also suggests a path forward towards precision molecular diagnostics at the protein–protein interaction level. PMID:23422673

  8. Computational analyses of synergism in small molecular network motifs.

    Directory of Open Access Journals (Sweden)

    Yili Zhang

    2014-03-01

    Full Text Available Cellular functions and responses to stimuli are controlled by complex regulatory networks that comprise a large diversity of molecular components and their interactions. However, achieving an intuitive understanding of the dynamical properties and responses to stimuli of these networks is hampered by their large scale and complexity. To address this issue, analyses of regulatory networks often focus on reduced models that depict distinct, reoccurring connectivity patterns referred to as motifs. Previous modeling studies have begun to characterize the dynamics of small motifs, and to describe ways in which variations in parameters affect their responses to stimuli. The present study investigates how variations in pairs of parameters affect responses in a series of ten common network motifs, identifying concurrent variations that act synergistically (or antagonistically to alter the responses of the motifs to stimuli. Synergism (or antagonism was quantified using degrees of nonlinear blending and additive synergism. Simulations identified concurrent variations that maximized synergism, and examined the ways in which it was affected by stimulus protocols and the architecture of a motif. Only a subset of architectures exhibited synergism following paired changes in parameters. The approach was then applied to a model describing interlocked feedback loops governing the synthesis of the CREB1 and CREB2 transcription factors. The effects of motifs on synergism for this biologically realistic model were consistent with those for the abstract models of single motifs. These results have implications for the rational design of combination drug therapies with the potential for synergistic interactions.

  9. Small Molecule Inhibitors of AI-2 Signaling in Bacteria: State-of-the-Art and Future Perspectives for Anti-Quorum Sensing Agents

    Science.gov (United States)

    Guo, Min; Gamby, Sonja; Zheng, Yue; Sintim, Herman O.

    2013-01-01

    Bacteria respond to different small molecules that are produced by other neighboring bacteria. These molecules, called autoinducers, are classified as intraspecies (i.e., molecules produced and perceived by the same bacterial species) or interspecies (molecules that are produced and sensed between different bacterial species). AI-2 has been proposed as an interspecies autoinducer and has been shown to regulate different bacterial physiology as well as affect virulence factor production and biofilm formation in some bacteria, including bacteria of clinical relevance. Several groups have embarked on the development of small molecules that could be used to perturb AI-2 signaling in bacteria, with the ultimate goal that these molecules could be used to inhibit bacterial virulence and biofilm formation. Additionally, these molecules have the potential to be used in synthetic biology applications whereby these small molecules are used as inputs to switch on and off AI-2 receptors. In this review, we highlight the state-of-the-art in the development of small molecules that perturb AI-2 signaling in bacteria and offer our perspective on the future development and applications of these classes of molecules. PMID:23994835

  10. Small-signal stability analysis for two-area interconnected power system with load frequency controller in coordination with FACTS and energy storage device

    Directory of Open Access Journals (Sweden)

    Ravi Shankar

    2016-06-01

    Full Text Available This paper deals with the modelling and small signal stability analysis for the two areas interconnected power system using a load frequency controller. The eigenvalues and the participation factor analysis are used to examine the small signal stability and contribution of different states in a particular eigenvalue of the system, respectively. A load frequency controller is designed to stabilize the frequency deviations which occur due to the small perturbation in the system. In this paper, the proposed control scheme consists of an integral controller in coordination with the Redox Flow Energy Storage System (RFESS and the Static Synchronous Series Compensator (SSSC. The dynamic responses of the overall system have been improved by the proposed controller, which is also verified with the help of eigenvalue and participation factor analysis. This analysis shows that overall system oscillation has been reduced through a proposed controller.

  11. Compressive Sampling of EEG Signals with Finite Rate of Innovation

    Directory of Open Access Journals (Sweden)

    Poh Kok-Kiong

    2010-01-01

    Full Text Available Analyses of electroencephalographic signals and subsequent diagnoses can only be done effectively on long term recordings that preserve the signals' morphologies. Currently, electroencephalographic signals are obtained at Nyquist rate or higher, thus introducing redundancies. Existing compression methods remove these redundancies, thereby achieving compression. We propose an alternative compression scheme based on a sampling theory developed for signals with a finite rate of innovation (FRI which compresses electroencephalographic signals during acquisition. We model the signals as FRI signals and then sample them at their rate of innovation. The signals are thus effectively represented by a small set of Fourier coefficients corresponding to the signals' rate of innovation. Using the FRI theory, original signals can be reconstructed using this set of coefficients. Seventy-two hours of electroencephalographic recording are tested and results based on metrices used in compression literature and morphological similarities of electroencephalographic signals are presented. The proposed method achieves results comparable to that of wavelet compression methods, achieving low reconstruction errors while preserving the morphologiies of the signals. More importantly, it introduces a new framework to acquire electroencephalographic signals at their rate of innovation, thus entailing a less costly low-rate sampling device that does not waste precious computational resources.

  12. A bead-based western for high-throughput cellular signal transduction analyses

    Science.gov (United States)

    Treindl, Fridolin; Ruprecht, Benjamin; Beiter, Yvonne; Schultz, Silke; Döttinger, Anette; Staebler, Annette; Joos, Thomas O.; Kling, Simon; Poetz, Oliver; Fehm, Tanja; Neubauer, Hans; Kuster, Bernhard; Templin, Markus F.

    2016-01-01

    Dissecting cellular signalling requires the analysis of large number of proteins. The DigiWest approach we describe here transfers the western blot to a bead-based microarray platform. By combining gel-based protein separation with immobilization on microspheres, hundreds of replicas of the initial blot are created, thus enabling the comprehensive analysis of limited material, such as cells collected by laser capture microdissection, and extending traditional western blotting to reach proteomic scales. The combination of molecular weight resolution, sensitivity and signal linearity on an automated platform enables the rapid quantification of hundreds of specific proteins and protein modifications in complex samples. This high-throughput western blot approach allowed us to identify and characterize alterations in cellular signal transduction that occur during the development of resistance to the kinase inhibitor Lapatinib, revealing major changes in the activation state of Ephrin-mediated signalling and a central role for p53-controlled processes. PMID:27659302

  13. Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange.

    Science.gov (United States)

    Burns, Michael C; Sun, Qi; Daniels, R Nathan; Camper, DeMarco; Kennedy, J Phillip; Phan, Jason; Olejniczak, Edward T; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

    2014-03-04

    Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active upstream receptor tyrosine kinases results in the deregulation of cellular signals governing growth and survival in ∼30% of all human cancers. However, the discovery of potent inhibitors of Ras has been difficult to achieve. Here, we report the identification of small molecules that bind to a unique pocket on the Ras:Son of Sevenless (SOS):Ras complex, increase the rate of SOS-catalyzed nucleotide exchange in vitro, and modulate Ras signaling pathways in cells. X-ray crystallography of Ras:SOS:Ras in complex with these molecules reveals that the compounds bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of multiple X-ray cocrystal structures. Mutational analyses confirmed the functional relevance of this binding site and showed it to be essential for compound activity. These molecules increase Ras-GTP levels and disrupt MAPK and PI3K signaling in cells at low micromolar concentrations. These small molecules represent tools to study the acute activation of Ras and highlight a pocket on SOS that may be exploited to modulate Ras signaling.

  14. Functional and gene network analyses of transcriptional signatures characterizing pre-weaned bovine mammary parenchyma or fat pad uncovered novel inter-tissue signaling networks during development

    Directory of Open Access Journals (Sweden)

    Lewin Harris A

    2010-05-01

    Full Text Available Abstract Background The neonatal bovine mammary fat pad (MFP surrounding the mammary parenchyma (PAR is thought to exert proliferative effects on the PAR through secretion of local modulators of growth induced by systemic hormones. We used bioinformatics to characterize transcriptomics differences between PAR and MFP from ~65 d old Holstein heifers. Data were mined to uncover potential crosstalk through the analyses of signaling molecules preferentially expressed in one tissue relative to the other. Results Over 9,000 differentially expressed genes (DEG; False discovery rate ≤ 0.05 were found of which 1,478 had a ≥1.5-fold difference between PAR and MFP. Within the DEG highly-expressed in PAR vs. MFP (n = 736 we noted significant enrichment of functions related to cell cycle, structural organization, signaling, and DNA/RNA metabolism. Only actin cytoskeletal signaling was significant among canonical pathways. DEG more highly-expressed in MFP vs. PAR (n = 742 belong to lipid metabolism, signaling, cell movement, and immune-related functions. Canonical pathways associated with metabolism and signaling, particularly immune- and metabolism-related were significantly-enriched. Network analysis uncovered a central role of MYC, TP53, and CTNNB1 in controlling expression of DEG highly-expressed in PAR vs. MFP. Similar analysis suggested a central role for PPARG, KLF2, EGR2, and EPAS1 in regulating expression of more highly-expressed DEG in MFP vs. PAR. Gene network analyses revealed putative inter-tissue crosstalk between cytokines and growth factors preferentially expressed in one tissue (e.g., ANGPTL1, SPP1, IL1B in PAR vs. MFP; ADIPOQ, IL13, FGF2, LEP in MFP vs. PAR with DEG preferentially expressed in the other tissue, particularly transcription factors or pathways (e.g., MYC, TP53, and actin cytoskeletal signaling in PAR vs. MFP; PPARG and LXR/RXR Signaling in MFP vs. PAR. Conclusions Functional analyses underscored a reciprocal influence in

  15. High-throughput screening identifies small molecules that bind to the RAS:SOS:RAS complex and perturb RAS signaling.

    Science.gov (United States)

    Burns, Michael C; Howes, Jennifer E; Sun, Qi; Little, Andrew J; Camper, DeMarco V; Abbott, Jason R; Phan, Jason; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

    2018-05-01

    K-RAS is mutated in approximately 30% of human cancers, resulting in increased RAS signaling and tumor growth. Thus, RAS is a highly validated therapeutic target, especially in tumors of the pancreas, lung and colon. Although directly targeting RAS has proven to be challenging, it may be possible to target other proteins involved in RAS signaling, such as the guanine nucleotide exchange factor Son of Sevenless (SOS). We have previously reported on the discovery of small molecules that bind to SOS1, activate SOS-mediated nucleotide exchange on RAS, and paradoxically inhibit ERK phosphorylation (Burns et al., PNAS, 2014). Here, we describe the discovery of additional, structurally diverse small molecules that also bind to SOS1 in the same pocket and elicit similar biological effects. We tested >160,000 compounds in a fluorescence-based assay to assess their effects on SOS-mediated nucleotide exchange. X-Ray structures revealed that these small molecules bind to the CDC25 domain of SOS1. Compounds that elicited high levels of nucleotide exchange activity in vitro increased RAS-GTP levels in cells, and inhibited phospho ERK levels at higher treatment concentrations. The identification of structurally diverse SOS1 binding ligands may assist in the discovery of new molecules designed to target RAS-driven tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Improvements to the extraction of an AlGaN/GaN HEMT small-signal model

    International Nuclear Information System (INIS)

    Pu Yan; Pang Lei; Wang Liang; Chen Xiaojuan; Li Chengzhan; Liu Xinyu

    2009-01-01

    The accurate extraction of AlGaN/GaN HEMT small-signal models, which is an important step in large-signal modeling, can exactly reflect the microwave performance of the physical structure of the device. A new method of extracting the parasitic elements is presented, and an open dummy structure is introduced to obtain the parasitic capacitances. With a Schottky resistor in the gate, a new method is developed to extract R g . In order to characterize the changes of the depletion region under various drain voltages, the drain delay factor is involved in the output conductance of the device. Compared to the traditional method, the fitting of S 11 and S 22 is improved, and f T and f max can be better predicted. The validity of the proposed method is verified with excellent correlation between the measured and simulated S-parameters in the range of 0.1 to 26.1 GHz. (semiconductor devices)

  17. Direct Targeting of β-Catenin by a Small Molecule Stimulates Proteasomal Degradation and Suppresses Oncogenic Wnt/β-Catenin Signaling

    Directory of Open Access Journals (Sweden)

    So-Young Hwang

    2016-06-01

    Full Text Available The Wnt/β-catenin signaling pathway plays a major role in tissue homeostasis, and its dysregulation can lead to various human diseases. Aberrant activation of β-catenin is oncogenic and is a critical driver in the development and progression of human cancers. Despite the significant potential of targeting the oncogenic β-catenin pathway for cancer therapy, the development of specific inhibitors remains insufficient. Using a T cell factor (TCF-dependent luciferase-reporter system, we screened for small-molecule compounds that act against Wnt/β-catenin signaling and identified MSAB (methyl 3-{[(4-methylphenylsulfonyl]amino}benzoate as a selective inhibitor of Wnt/β-catenin signaling. MSAB shows potent anti-tumor effects selectively on Wnt-dependent cancer cells in vitro and in mouse cancer models. MSAB binds to β-catenin, promoting its degradation, and specifically downregulates Wnt/β-catenin target genes. Our findings might represent an effective therapeutic strategy for cancers addicted to the Wnt/β-catenin signaling pathway.

  18. Retroactive signaling in short signaling pathways.

    Directory of Open Access Journals (Sweden)

    Jacques-Alexandre Sepulchre

    Full Text Available In biochemical signaling pathways without explicit feedback connections, the core signal transduction is usually described as a one-way communication, going from upstream to downstream in a feedforward chain or network of covalent modification cycles. In this paper we explore the possibility of a new type of signaling called retroactive signaling, offered by the recently demonstrated property of retroactivity in signaling cascades. The possibility of retroactive signaling is analysed in the simplest case of the stationary states of a bicyclic cascade of signaling cycles. In this case, we work out the conditions for which variables of the upstream cycle are affected by a change of the total amount of protein in the downstream cycle, or by a variation of the phosphatase deactivating the same protein. Particularly, we predict the characteristic ranges of the downstream protein, or of the downstream phosphatase, for which a retroactive effect can be observed on the upstream cycle variables. Next, we extend the possibility of retroactive signaling in short but nonlinear signaling pathways involving a few covalent modification cycles.

  19. Oncogenic Signaling by Leukemia-Associated Mutant Cbl Proteins

    Science.gov (United States)

    Nadeau, Scott; An, Wei; Palermo, Nick; Feng, Dan; Ahmad, Gulzar; Dong, Lin; Borgstahl, Gloria E. O.; Natarajan, Amarnath; Naramura, Mayumi; Band, Vimla; Band, Hamid

    2013-01-01

    Members of the Cbl protein family (Cbl, Cbl-b, and Cbl-c) are E3 ubiquitin ligases that have emerged as critical negative regulators of protein tyrosine kinase (PTK) signaling. This function reflects their ability to directly interact with activated PTKs and to target them as well as their associated signaling components for ubiquitination. Given the critical roles of PTK signaling in driving oncogenesis, recent studies in animal models and genetic analyses in human cancer have firmly established that Cbl proteins function as tumor suppressors. Missense mutations or small in-frame deletions within the regions of Cbl protein that are essential for its E3 activity have been identified in nearly 5% of leukemia patients with myelodysplastic/myeloproliferative disorders. Based on evidence from cell culture studies, in vivo models and clinical data, we discuss the potential signaling mechanisms of mutant Cbl-driven oncogenesis. Mechanistic insights into oncogenic Cbl mutants and associated animal models are likely to enhance our understanding of normal hematopoietic stem cell homeostasis and provide avenues for targeted therapy of mutant Cbl-driven cancers. PMID:23997989

  20. Analyser of sweeping electron beam

    International Nuclear Information System (INIS)

    Strasser, A.

    1993-01-01

    The electron beam analyser has an array of conductors that can be positioned in the field of the sweeping beam, an electronic signal treatment system for the analysis of the signals generated in the conductors by the incident electrons and a display for the different characteristics of the electron beam

  1. Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish

    Science.gov (United States)

    Swartz, Mary E.; McCarthy, Neil; Norrie, Jacqueline L.; Eberhart, Johann K.

    2016-01-01

    The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. PMID:27122171

  2. Application of small-size antennas for estimation of angles of arrival of HF signals scattered by ionospheric irregularities

    Science.gov (United States)

    Guo, Qiang; Galushko, Volodymyr G.; Zalizovski, Andriy V.; Kashcheyev, Sergiy B.; Zheng, Yu

    2018-05-01

    A modification of the Doppler Interferometry Technique is suggested to enable estimating angles of arrival of comparatively broadband HF signals scattered by random irregularities of the ionospheric plasma with the use of small-size weakly directional antennas. The technique is based on the measurements of cross-spectra phases of the probe radiation recorded at least in three spatially separated points. The developed algorithm has been used to investigate the angular and frequency-time characteristics of HF signals propagating at frequencies above the maximum usable one (MUF) for the direct radio path Moscow-Kharkiv. The received signal spectra show presence of three families of spatial components attributed, respectively, to scattering by plasma irregularities near the middle point of the radio path, ground backscatter signals and scattering of the sounding signals by the intense plasma turbulence associated with auroral activations. It has been shown that the regions responsible for the formation of the third family components are located well inside the auroral oval. The drift velocity and direction of the auroral ionosphere plasma have been determined. The obtained estimates are consistent with the classical conception of the ionospheric plasma convection at high latitudes and do not contradict the results of investigations of the auroral ionosphere dynamics using the SuperDARN network.

  3. Signal and data processing of small targets 1989; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989

    Science.gov (United States)

    Drummond, Oliver E. (Editor)

    1989-01-01

    The present conference on digital signal processing, association and filtering techniques, and multiple-sensor/multiple-tracking techniques, discusses single-frame velocity estimation, efficient target extraction for laser radar imagery, precision target tracking for small extended objects, IR clutter partitioning for matched filter design, the maximum-likelihood approach to gamma circumvention, position estimation for optical point targets using staring detector arrays, and a multiple-scan signal processing technique for area-moving target indication. Also discussed are a proportional integral estimator, the prediction of track purity in tracking performance evaluations, synchronization and fault-tolerance in a distributed tracker, the benefits of soft sensors and probabilistic fusion, and testing track initiation algorithms fusing two-dimensional tracks.

  4. Identifying Neutrino Mass Hierarchy at Extremely Small θ13 through Earth Matter Effects in a Supernova Signal

    International Nuclear Information System (INIS)

    Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro

    2008-01-01

    Collective neutrino flavor transformations deep inside a supernova are sensitive to the neutrino mass hierarchy even at extremely small values of θ 13 . Exploiting this effect, we show that comparison of the antineutrino signals from a galactic supernova in two megaton class water Cherenkov detectors, one of which is shadowed by Earth, will enable us to distinguish between the hierarchies if sin 2 θ 13 -5 , where long baseline neutrino experiments would be ineffectual

  5. Influence of Wind Plant Ancillary Voltage Control on System Small Signal Stability

    DEFF Research Database (Denmark)

    Su, Chi; Chen, Zhe

    2012-01-01

    As a common tendency, large-scale wind farms are increasingly connected to the transmission system of modern power grids. This introduces some new challenges to the connected power systems, and the transmission system operators (TSOs) have to put some new requirements as part of the grid codes...... on the integration of wind farms. One common requirement to wind farms is the function of system voltage control which can be implemented in the grid-side convertor controller of a variable speed wind turbine. This ancillary voltage control provided by wind farms could have some influence on the system small signal...... stability. This paper implements an ancillary voltage control strategy on a direct-drive-full-convertor-based wind farm and studies its influence on the damping ratio values of the dominant oscillation mode within the connected power system. All the calculations and simulations are conducted in DIg...

  6. Vibration tests and analyses of the reactor building model on a small scale

    International Nuclear Information System (INIS)

    Tsuchiya, Hideo; Tanaka, Mitsuru; Ogihara, Yukio; Moriyama, Ken-ichi; Nakayama, Masaaki

    1985-01-01

    The purpose of this paper is to describe the vibration tests and the simulation analyses of the reactor building model on a small scale. The model vibration tests were performed to investigate the vibrational characteristics of the combined super-structure and to verify the computor code based on Dr. H. Tajimi's Thin Layered Element Theory, using the uniaxial shaking table (60 cm x 60 cm). The specimens consist of ground model, three structural model (prestressed concrete containment vessel, inner concrete structure, and enclosure building), a combined structural model and a combined structure-soil interaction model. These models are made of silicon-rubber, and they have a scale of 1:600. Harmonic step by step excitation of 40 gals was performed to investigate the vibrational characteristics for each structural model. The responses of the specimen to harmonic excitation were measured by optical displacement meters, and analyzed by a real time spectrum analyzer. The resonance and phase lag curves of the specimens to the shaking table were obtained respectively. As for the tests of a combined structure-soil interaction model, three predominant frequencies were observed in the resonance curves. These values were in good agreement with the analytical transfer function curves on the computer code. From the vibration tests and the simulation analyses, the silicon-rubber model test is useful for the fundamental study of structural problems. The computer code based on the Thin Element Theory can simulate well the test results. (Kobozono, M.)

  7. Wide-Area Assessment of Aperiodic Small Signal Rotor Angle Stability in Real-Time

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Nielsen, Arne Hejde; Østergaard, Jacob

    2013-01-01

    This paper presents the details of a new real-time stability assessment method. The method assesses a particular mechanism of stability: each generator’s capability to generate sufficient steady state electromechanical torque. The lack of sufficient steady state torque causes aperiodic increase...... of multiple operating points is derived in the paper. Finally, results from time-domain simulation of instability scenarios in the Nordic32 test system are presented and results used for testing the assessment method. The results illustrate the method’s capability to efficiently identify the location...... in rotor angle and a loss of synchronism, referred to as aperiodic small signal instability. The paper provides the theoretical background of the method and an analytical assessment criterion. Furthermore, a mathematical mapping of the generators’ operating points that enables informative visualization...

  8. Consequence and impact of electric utility industry restructuring on transient stability and small-signal stability analysis

    International Nuclear Information System (INIS)

    Vittal, V.

    2000-01-01

    The electric utility industry is undergoing unprecedented changes in its structure worldwide. With the advent of an open market environment and competition in the industry, and restructuring of the industry into separate generation, transmission, and distribution entities, new issues in power system operation and planning are inevitable. One of the major consequences of this new electric utility environment is the greater emphasis on reliability and secure operation of the power system. This paper examines the impact of restructuring on power system dynamic analysis. It specifically addresses issues related to transient stability analysis and small-signal stability analysis. Four major topics to examine the effect on the nature of studies conducted are considered. These topics are (1) system adequacy and security, (2) system modeling data requirements, (3) system protection and control, and (4) system restoration. The consequences and impact of each of these topics on the nature of the studies conducted are examined and discussed. The emphasis on greater reliability has led to a clearer enunciation of standards, measurements, and guides in some countries. These requirements will result in: (1) more measurements on existing systems, (2) rigorous analysis of transient stability and small-signal stability to determine operating limits and plan systems, (3) greater emphasis on studies to verify coordination and proper performance of protection and controls, and (4) development of a detailed plan for system restoration in the case of wide-spread outages

  9. Gut microbial colonization orchestrates TLR2 expression, signaling and epithelial proliferation in the small intestinal mucosa.

    Directory of Open Access Journals (Sweden)

    Nives Hörmann

    Full Text Available The gut microbiota is an environmental factor that determines renewal of the intestinal epithelium and remodeling of the intestinal mucosa. At present, it is not resolved if components of the gut microbiota can augment innate immune sensing in the intestinal epithelium via the up-regulation of Toll-like receptors (TLRs. Here, we report that colonization of germ-free (GF Swiss Webster mice with a complex gut microbiota augments expression of TLR2. The microbiota-dependent up-regulation of components of the TLR2 signaling complex could be reversed by a 7 day broad-spectrum antibiotic treatment. TLR2 downstream signaling via the mitogen-activated protein kinase (ERK1/2 and protein-kinase B (AKT induced by bacterial TLR2 agonists resulted in increased proliferation of the small intestinal epithelial cell line MODE-K. Mice that were colonized from birth with a normal gut microbiota (conventionally-raised; CONV-R showed signs of increased small intestinal renewal and apoptosis compared with GF controls as indicated by elevated mRNA levels of the proliferation markers Ki67 and Cyclin D1, elevated transcripts of the apoptosis marker Caspase-3 and increased numbers of TUNEL-positive cells per intestinal villus structure. In accordance, TLR2-deficient mice showed reduced proliferation and reduced apoptosis. Our findings suggest that a tuned proliferation response of epithelial cells following microbial colonization could aid to protect the host from its microbial colonizers and increase intestinal surface area.

  10. Reverse-phase phosphoproteome analysis of signaling pathways induced by Rift valley fever virus in human small airway epithelial cells.

    Directory of Open Access Journals (Sweden)

    Taissia G Popova

    Full Text Available Rift valley fever virus (RVFV infection is an emerging zoonotic disease endemic in many countries of sub-Saharan Africa and in Egypt. In this study we show that human small airway epithelial cells are highly susceptible to RVFV virulent strain ZH-501 and the attenuated strain MP-12. We used the reverse-phase protein arrays technology to identify phosphoprotein signaling pathways modulated during infection of cultured airway epithelium. ZH-501 infection induced activation of MAP kinases (p38, JNK and ERK and downstream transcriptional factors [STAT1 (Y701, ATF2 (T69/71, MSK1 (S360 and CREB (S133]. NF-κB phosphorylation was also increased. Activation of p53 (S15, S46 correlated with the increased levels of cleaved effector caspase-3, -6 and -7, indicating activation of the extrinsic apoptotic pathway. RVFV infection downregulated phosphorylation of a major anti-apoptotic regulator of survival pathways, AKT (S473, along with phosphorylation of FOX 01/03 (T24/31 which controls cell cycle arrest downstream from AKT. Consistent with this, the level of apoptosis inhibitor XIAP was decreased. However, the intrinsic apoptotic pathway marker, caspase-9, demonstrated only a marginal activation accompanied by an increased level of the inhibitor of apoptosome formation, HSP27. Concentration of the autophagy marker, LC3B, which often accompanies the pro-survival signaling, was decreased. Cumulatively, our analysis of RVFV infection in lung epithelium indicated a viral strategy directed toward the control of cell apoptosis through a number of transcriptional factors. Analyses of MP-12 titers in challenged cells in the presence of MAPK inhibitors indicated that activation of p38 represents a protective cell response while ERK activation controls viral replication.

  11. Measurements of Interferometer Parameters at Reception of GLONASS and GPS Signals

    Directory of Open Access Journals (Sweden)

    Nechaeva M.

    2016-10-01

    Full Text Available The present paper deals with the calibration method of interferometers with antennas having a small effective area, on the quasinoise signals of GLONASS and GPS navigation satellites. Algorithms for calculation of antenna coordinates and instrumental delay from the analysis of correlation interferometer response to signals of satellites in the near field of the instrument were reviewed. The method was tested in VLBI experiments on interferometers with medium and large baselines that included radio telescopes of NIRFI and VIRAC. The values of the antenna coordinates and instrumental delay with an error within the limits of one discrete were obtained. The sources of measurement errors and ways to improve the accuracy of results were analysed.

  12. Transcriptome profiling of the theca interna in transition from small to large antral ovarian follicles.

    Directory of Open Access Journals (Sweden)

    Nicholas Hatzirodos

    Full Text Available The theca interna layer of the ovarian follicle forms during the antral stage of follicle development and lies adjacent to and directly outside the follicular basal lamina. It supplies androgens and communicates with the granulosa cells and the oocyte by extracellular signaling. To better understand developmental changes in the theca interna, we undertook transcriptome profiling of the theca interna from small (3-5 mm, n = 10 and large (9-12 mm, n = 5 healthy antral bovine follicles, representing a calculated >7-fold increase in the amount of thecal tissue. Principal Component Analysis and hierarchical classification of the signal intensity plots for the arrays showed no clustering of the theca interna samples into groups depending on follicle size or subcategories of small follicles. From the over 23,000 probe sets analysed, only 76 were differentially expressed between large and small healthy follicles. Some of the differentially expressed genes were associated with processes such as myoblast differentiation, protein ubiquitination, nitric oxide and transforming growth factor β signaling. The most significant pathway affected from our analyses was found to be Wnt signaling, which was suppressed in large follicles via down-regulation of WNT2B and up-regulation of the inhibitor FRZB. These changes in the transcriptional profile could have been due to changes in cellular function or alternatively since the theca interna is composed of a number of different cell types it could have been due to any systematic change in the volume density of any particular cell type. However, our study suggests that the transcriptional profile of the theca interna is relatively stable during antral follicle development unlike that of granulosa cells observed previously. Thus both the cellular composition and cellular behavior of the theca interna and its contribution to follicular development appear to be relatively constant throughout the follicle growth

  13. Defying c-Abl signaling circuits through small allosteric compounds

    Directory of Open Access Journals (Sweden)

    Stefania eGonfloni

    2014-11-01

    Full Text Available Many extracellular and intracellular signals promote the c-Abl tyrosine kinase activity. c-Abl in turn triggers a multitude of changes either in protein phosphorylation or in gene expression in the cell. Yet, c-Abl takes part in diverse signaling routes because of several domains linked to its catalytic core. Complex conformational changes turn on and off its kinase activity. These changes affect surface features of the c-Abl kinase and likely its capability to bind actin and/or DNA. Two specific inhibitors (ATP-competitive or allosteric compounds regulate the c-Abl kinase through different mechanisms. NMR studies show that a c-Abl fragment (SH3-SH2-linker-SH1 adopts different conformational states upon binding to each inhibitor. This supports an unconventional use for allosteric compounds to unraveling physiological c-Abl signaling circuits.

  14. Small-signal modulation and differential gain of red-emitting (λ = 630 nm) InGaN/GaN quantum dot lasers

    Energy Technology Data Exchange (ETDEWEB)

    Frost, Thomas; Banerjee, Animesh; Bhattacharya, Pallab, E-mail: pkb@eecs.umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)

    2013-11-18

    We report small-signal modulation bandwidth and differential gain measurements of a ridge waveguide In{sub 0.4}Ga{sub 0.6}N/GaN quantum dot laser grown by molecular beam epitaxy. The laser peak emission is at λ = 630 nm. The −3 dB bandwidth of an 800 μm long device was measured to be 2.4 GHz at 250 mA under pulsed biasing, demonstrating the possibility of high-speed operation of these devices. The differential gain was measured to be 5.3 × 10{sup −17} cm{sup 2}, and a gain compression factor of 2.87 × 10{sup −17} cm{sup 3} is also derived from the small-signal modulation response.

  15. TUSC3 induces autophagy in human non-small cell lung cancer cells through Wnt/β-catenin signaling.

    Science.gov (United States)

    Peng, Yun; Cao, Jun; Yao, Xiao-Yi; Wang, Jian-Xin; Zhong, Mei-Zuo; Gan, Ping-Ping; Li, Jian-Huang

    2017-08-08

    We investigated the effects of tumor suppressor candidate 3 ( TUSC3 ) on autophagy in human non-small cell lung cancer (NSCLC) cells. A total of 118 NSCLC patients (88 males and 30 females) who underwent surgery at our institute were enrolled in the study. Immunohistochemical analysis revealed that TUSC3 protein expression was lower in NSCLC specimens than adjacent normal tissue. Correspondingly, there was greater methylation of TUSC3 in NSCLC than adjacent normal tissue. After transient transfection of A549 NSCLC cells with constructs designed to up-regulate or down-regulate TUSC3 expression, we analyzed the effects of inhibiting the Wnt pathway (XAV939) and autophagy (chloroquine, CQ) on the behavior of NSCLC cells. We also performed TOP/FOP-Flash reporter assays, MTT assays, Annexin V-FITC/propidium iodide staining, and acridine orange staining to evaluate Wnt/β-catenin signaling, cell proliferation, apoptosis, and autophagy, respectively. Expression of Wnt/β-catenin pathway components and autophagy-related proteins was analyzed using qRT-PCR and Western blotting. We found that TUSC3 inhibited cell proliferation and promoted both apoptosis and autophagy in A549 cells. In addition, TUSC3 increased expression of autophagy-related proteins. It also increased expression of Wnt/β-catenin signaling pathway components and promoted nuclear transfer of β-catenin, resulting in activation of Wnt/β-catenin signaling. TUSC3 thus induces autophagy in human NSCLC cells through activation of the Wnt/β-catenin signaling pathway.

  16. Inhibition of TLR2 signaling by small molecule inhibitors targeting a pocket within the TLR2 TIR domain

    Science.gov (United States)

    Mistry, Pragnesh; Laird, Michelle H. W.; Schwarz, Ryan S.; Greene, Shannon; Dyson, Tristan; Snyder, Greg A.; Xiao, Tsan Sam; Chauhan, Jay; Fletcher, Steven; Toshchakov, Vladimir Y.; MacKerell, Alexander D.; Vogel, Stefanie N.

    2015-01-01

    Toll-like receptor (TLR) signaling is initiated by dimerization of intracellular Toll/IL-1 receptor resistance (TIR) domains. For all TLRs except TLR3, recruitment of the adapter, myeloid differentiation primary response gene 88 (MyD88), to TLR TIR domains results in downstream signaling culminating in proinflammatory cytokine production. Therefore, blocking TLR TIR dimerization may ameliorate TLR2-mediated hyperinflammatory states. The BB loop within the TLR TIR domain is critical for mediating certain protein–protein interactions. Examination of the human TLR2 TIR domain crystal structure revealed a pocket adjacent to the highly conserved P681 and G682 BB loop residues. Using computer-aided drug design (CADD), we sought to identify a small molecule inhibitor(s) that would fit within this pocket and potentially disrupt TLR2 signaling. In silico screening identified 149 compounds and 20 US Food and Drug Administration-approved drugs based on their predicted ability to bind in the BB loop pocket. These compounds were screened in HEK293T-TLR2 transfectants for the ability to inhibit TLR2-mediated IL-8 mRNA. C16H15NO4 (C29) was identified as a potential TLR2 inhibitor. C29, and its derivative, ortho-vanillin (o-vanillin), inhibited TLR2/1 and TLR2/6 signaling induced by synthetic and bacterial TLR2 agonists in human HEK-TLR2 and THP-1 cells, but only TLR2/1 signaling in murine macrophages. C29 failed to inhibit signaling induced by other TLR agonists and TNF-α. Mutagenesis of BB loop pocket residues revealed an indispensable role for TLR2/1, but not TLR2/6, signaling, suggesting divergent roles. Mice treated with o-vanillin exhibited reduced TLR2-induced inflammation. Our data provide proof of principle that targeting the BB loop pocket is an effective approach for identification of TLR2 signaling inhibitors. PMID:25870276

  17. Proton density differences in signal characteristics of multiple sclerosis plaques versus white matter lesions of small vessel disease and vasculitis on high-field strength MR images

    International Nuclear Information System (INIS)

    Peyster, R.G.; Siegal, T.L.

    1990-01-01

    This paper determines if variations in signal intensity characteristics on multi-spin-echo images obtained with a high-field-strength magnet can be useful in differentiating demyelinating plaques of multiple sclerosis from other pathologic white matter processes due to small vessel disease and vasculities. Using the first of two multi-spin-echo images obtained with a General Electric 1.5-T magnet, the investigators compared signal intensity characteristics in 30 patients with a firm clinical diagnosis of multiple sclerosis versus a control group of 30 patients with a known clinical history of small-vessel disease and vasculitis are isodense to gray matter on proton-density images

  18. Hydrogeologic characterization and evolution of the 'excavation damaged zone' by statistical analyses of pressure signals: application to galleries excavated at the clay-stone sites of Mont Terri (Ga98) and Tournemire (Ga03)

    International Nuclear Information System (INIS)

    Fatmi, H.; Ababou, R.; Matray, J.M.; Joly, C.

    2010-01-01

    Document available in extended abstract form only. This paper presents methods of statistical analysis and interpretation of hydrogeological signals in clayey formations, e.g., pore water pressure and atmospheric pressure. The purpose of these analyses is to characterize the hydraulic behaviour of this type of formation in the case of a deep repository of Mid- Level/High-Level and Long-lived radioactive wastes, and to study the evolution of the geologic formation and its EDZ (Excavation Damaged Zone) during the excavation of galleries. We focus on galleries Ga98 and Ga03 in the sites of Mont Terri (Jura, Switzerland) and Tournemire (France, Aveyron), through data collected in the BPP- 1 and PH2 boreholes, respectively. The Mont Terri site, crossing the Aalenian Opalinus clay-stone, is an underground laboratory managed by an international consortium, namely the Mont Terri project (Switzerland). The Tournemire site, crossing the Toarcian clay-stone, is an Underground Research facility managed by IRSN (France). We have analysed pore water and atmospheric pressure signals at these sites, sometimes in correlation with other data. The methods of analysis are based on the theory of stationary random signals (correlation functions, Fourier spectra, transfer functions, envelopes), and on multi-resolution wavelet analysis (adapted to nonstationary and evolutionary signals). These methods are also combined with filtering techniques, and they can be used for single signals as well as pairs of signals (cross-analyses). The objective of this work is to exploit pressure measurements in selected boreholes from the two compacted clay sites, in order to: - evaluate phenomena affecting the measurements (earth tides, barometric pressures..); - estimate hydraulic properties (specific storage..) of the clay-stones prior to excavation works and compare them with those estimated by pulse or slug tests on shorter time scales; - analyze the effects of drift excavation on pore pressures

  19. Detection of Noise in Composite Step Signal Pattern by Visualizing Signal Waveforms

    Directory of Open Access Journals (Sweden)

    Chaman Verma

    2018-03-01

    Full Text Available The Step Composite Signals is the combination of vital informative signals that are compressed and coded to produce a predefined test image on a display device. It carries the desired sequence of information from source to destination. This information may be transmitted as digital signal, video information or data signal required as an input for the destination module. For testing of display panels, Composite Test Signals are the most important attribute of test signal transmission system. In the current research paper we present an approach for the noise detection in Composite Step Signal by analysing Composite Step Signal waveforms. The analysis of the signal waveforms reveals that the noise affected components of the signal and subsequently noise reduction process is initiated which targets noisy signal component only. Thus the quality of signal is not compromised during noise reduction process.

  20. Recycling domains in plant cell morphogenesis: small GTPase effectors, plasma membrane signalling and the exocyst.

    Science.gov (United States)

    Zárský, Viktor; Potocký, Martin

    2010-04-01

    The Rho/Rop small GTPase regulatory module is central for initiating exocytotically ACDs (active cortical domains) in plant cell cortex, and a growing array of Rop regulators and effectors are being discovered in plants. Structural membrane phospholipids are important constituents of cells as well as signals, and phospholipid-modifying enzymes are well known effectors of small GTPases. We have shown that PLDs (phospholipases D) and their product, PA (phosphatidic acid), belong to the regulators of the secretory pathway in plants. We have also shown that specific NOXs (NADPH oxidases) producing ROS (reactive oxygen species) are involved in cell growth as exemplified by pollen tubes and root hairs. Most plant cells exhibit several distinct plasma membrane domains (ACDs), established and maintained by endocytosis/exocytosis-driven membrane protein recycling. We proposed recently the concept of a 'recycling domain' (RD), uniting the ACD and the connected endosomal recycling compartment (endosome), as a dynamic spatiotemporal entity. We have described a putative GTPase-effector complex exocyst involved in exocytic vesicle tethering in plants. Owing to the multiplicity of its Exo70 subunits, this complex, along with many RabA GTPases (putative recycling endosome organizers), may belong to core regulators of RD organization in plants.

  1. A review of signals used in sleep analysis

    International Nuclear Information System (INIS)

    Roebuck, A; Monasterio, V; Gederi, E; Osipov, M; Behar, J; Clifford, G D; Malhotra, A; Penzel, T

    2014-01-01

    This article presents a review of signals used for measuring physiology and activity during sleep and techniques for extracting information from these signals. We examine both clinical needs and biomedical signal processing approaches across a range of sensor types. Issues with recording and analysing the signals are discussed, together with their applicability to various clinical disorders. Both univariate and data fusion (exploiting the diverse characteristics of the primary recorded signals) approaches are discussed, together with a comparison of automated methods for analysing sleep. (topical review)

  2. Millimeter-wave small-signal modeling with optimizing sensitive-parameters for metamorphic high electron mobility transistors

    International Nuclear Information System (INIS)

    Moon, S-W; Baek, Y-H; Han, M; Rhee, J-K; Kim, S-D; Oh, J-H

    2010-01-01

    In this paper, we present a simple and reliable technique for determining the small-signal equivalent circuit model parameters of the 0.1 µm metamorphic high electron mobility transistors (MHEMTs) in a millimeter-wave frequency range. The initial eight extrinsic parameters of the MHEMT are extracted using two S-parameter (scattering parameter) sets measured under the pinched-off and zero-biased cold field-effect transistor conditions by avoiding the forward gate biasing. Furthermore, highly calibration-sensitive values of the R s , L s and C pd are optimized by using a gradient optimization method to improve the modeling accuracy. The accuracy enhancement of this procedure is successfully verified with an excellent correlation between the measured and calculated S-parameters up to 65 GHz

  3. Small-molecule pheromones and hormones controlling nematode development.

    Science.gov (United States)

    Butcher, Rebecca A

    2017-05-17

    The existence of small-molecule signals that influence development in Caenorhabditis elegans has been known for several decades, but only in recent years have the chemical structures of several of these signals been established. The identification of these signals has enabled connections to be made between these small molecules and fundamental signaling pathways in C. elegans that influence not only development but also metabolism, fertility, and lifespan. Spurred by these important discoveries and aided by recent advances in comparative metabolomics and NMR spectroscopy, the field of nematode chemistry has the potential to expand dramatically in the coming years. This Perspective will focus on small-molecule pheromones and hormones that influence developmental events in the nematode life cycle (ascarosides, dafachronic acids, and nemamides), will cover more recent work regarding the biosynthesis of these signals, and will explore how the discovery of these signals is transforming our understanding of nematode development and physiology.

  4. The Rac1 hypervariable region in targeting and signaling

    Science.gov (United States)

    Lam, B. Daniel; Hordijk, Peter L.

    2013-01-01

    Cellular signaling by small GTPases is critically dependent on proper spatio-temporal orchestration of activation and output. In addition to their core G (guanine nucleotide binding)-domain, small GTPases comprise a hypervariable region (HVR) and a lipid anchor that are generally accepted to control subcellullar localization. The HVR encodes in many small GTPases a polybasic region (PBR) that permits charge-mediated association to the inner leaflet of the plasma membrane or to intracellular organelles. Over the past 15–20 years, evidence has accumulated for specific protein–protein interactions, mediated by the HVR, that control both targeting and signaling specificity of small GTPases. Using the RhoGTPase Rac1 as a paradigm we here review a series of protein partners that require the Rac1 HVR for association and that control various aspects of localized Rac1 signaling. Some of these proteins represent Rac1 activators, whereas others mediate Rac1 inactivation and degradation and yet others potentiate Rac1 downstream signaling. Finally, evidence is discussed which shows that the HVR of Rac1 also contributes to effector interactions, co-operating with the N-terminal effector domain. The complexity of localized Rac1 signaling, reviewed here, is most likely exemplary for many other small GTPases as well, representing a challenge to identify and define similar mechanisms controlling the specific signaling induced by small GTPases. PMID:23354415

  5. RF measurements I: signal receiving techniques

    CERN Document Server

    Caspers, F

    2011-01-01

    For the characterization of components, systems and signals in the RF and microwave range, several dedicated instruments are in use. In this paper the fundamentals of the RF-signal sampling technique, which has found widespread applications in 'digital' oscilloscopes and sampling scopes, are discussed. The key element in these front-ends is the Schottky diode which can be used either as an RF mixer or as a single sampler. The spectrum analyser has become an absolutely indispensable tool for RF signal analysis. Here the front-end is the RF mixer as the RF section of modern spectrum analysers has a rather complex architecture. The reasons for this complexity and certain working principles as well as limitations are discussed. In addition, an overview of the development of scalar and vector signal analysers is given. For the determination of the noise temperature of a one-port and the noise figure of a two-port, basic concepts and relations are shown. A brief discussion of commonly used noise measurement techniq...

  6. Dephasing in coherent communication with weak signal states

    International Nuclear Information System (INIS)

    Jarzyna, Marcin; Banaszek, Konrad; Demkowicz-Dobrzański, Rafał

    2014-01-01

    We analyse the ultimate quantum limit on the accessible information for an optical communication scheme when time bins carry coherent light pulses prepared in one of several orthogonal modes and the phase undergoes diffusion after each channel use. This scheme, an example of a quantum memory channel, can be viewed as noisy pulse position modulation (PPM) keying with phase fluctuations occurring between consecutive PPM symbols. We derive a general expression for the output states in the Fock basis and implement a numerical procedure to calculate the Holevo quantity. Using asymptotic properties of Toeplitz matrices, we also present an analytic expression for the Holevo quantity valid for very weak signals and sufficiently strong dephasing when the dominant contribution comes from the single-photon sector in the Hilbert space of signal states. Based on numerical results we conjecture an inequality for contributions to the Holevo quantity from multiphoton sectors which implies that in the asymptotic limit of weak signals, for arbitrarily small dephasing the accessible information scales linearly with the average number of photons contained in the pulse. Such behaviour presents a qualitative departure from the fully coherent case. (paper)

  7. Distinct signaling roles of ceramide species in yeast revealed through systematic perturbation and systems biology analyses.

    Science.gov (United States)

    Montefusco, David J; Chen, Lujia; Matmati, Nabil; Lu, Songjian; Newcomb, Benjamin; Cooper, Gregory F; Hannun, Yusuf A; Lu, Xinghua

    2013-10-29

    Ceramide, the central molecule of sphingolipid metabolism, is an important bioactive molecule that participates in various cellular regulatory events and that has been implicated in disease. Deciphering ceramide signaling is challenging because multiple ceramide species exist, and many of them may have distinct functions. We applied systems biology and molecular approaches to perturb ceramide metabolism in the yeast Saccharomyces cerevisiae and inferred causal relationships between ceramide species and their potential targets by combining lipidomic, genomic, and transcriptomic analyses. We found that during heat stress, distinct metabolic mechanisms controlled the abundance of different groups of ceramide species and provided experimental support for the importance of the dihydroceramidase Ydc1 in mediating the decrease in dihydroceramides during heat stress. Additionally, distinct groups of ceramide species, with different N-acyl chains and hydroxylations, regulated different sets of functionally related genes, indicating that the structural complexity of these lipids produces functional diversity. The transcriptional modules that we identified provide a resource to begin to dissect the specific functions of ceramides.

  8. Trace element analyses of fluid inclusions using laser ablation ICP-MS

    Directory of Open Access Journals (Sweden)

    Cong-ying Li

    2018-03-01

    Full Text Available Fluid inclusions are records of the physico-chemical conditions of fluid–rock interactions during magmatism, mineralization and fluid percolation and mixing processes. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS is a powerful tool for in situ analyses of small samples at micrometer levels. Here we report in situ analyses of fluid inclusions using LA-ICP-MS method. NIST SRM glasses and 23Na are generally used as external and internal standards for LA-ICP-MS analysis of fluid inclusion, respectively, although the RSD of microthermometric estimation of 23Na is about 20% and even worse, the background signal of Na is high for most ICP-MS. Using well-characterized natural fluids inclusion, we show that RESOlution S-155 laser system analyze fluid inclusions in quartz and determine the trace element concentrations. Resonetics RESOlution S-155 laser has the advantage of the motorized Z stage can be used to accommodate variation of sample height or sample topography and height difference between samples, which is very important for analyzing the fluid inclusion in quartz. Our results suggest laser energy density is 25 J/cm2, laser pulse repetition rates are commonly between 6 and 10 Hz to avoid the fissuring of quartz and obtain adequate results. For this LA-ICP-MS analysis, uncertainty on 35Cl content is around 40% because of intensity of the 35Cl signal is three orders of magnitude less intense than the intensity of the 23Na signal. Nevertheless, it is still a useful reference for fluid inclusion analyses in addition to 23Na. This technique can be applied to a range of hydrothermal geology problems, including determining the origins of ore forming brines and ore deposition processes, mapping metamorphic and hydrothermal fluid provinces and pathways, and constraining the effects of fluid–rock reactions and fluid mixing.

  9. Generalised small signal analysis of a DAR /Double Avalanche Region/ IMPATT diode

    Science.gov (United States)

    Datta, D. N.; Pal, B. B.

    1982-06-01

    A generalized small signal analysis of a DAR IMPATT diode is carried out using recent values of ionization rates and saturated drift velocities of electrons and holes for Si and GaAs taking both the drift and the diffusion of charge carriers into account. The results show similar discrete negative conductance frequency bands separated by positive conductance frequency bands for an asymmetrical structure as in the ideal case (Som et al., 1974), establishing that the harmonically related frequencies can be avoided in the Si DAR IMPATT diode. In contrast to the ideal case, however, the symmetrical DAR IMPATT here also exhibits finite negative conductance. The GaAs DAR IMPATT shows variations of negative conductance that are similar to those in Si at high frequencies (in the mm wave range); at the low frequency side (less than 1 GHz), however, the IMPATT gives uniform negative conductances unlike Si where the negative conductance comes only at higher frequencies. Consideration is given in the calculations to thin depletion layers (0.8, 1, and 2 microns) to show the usefulness of the device in the mm wave range.

  10. Small-Signal Modeling, Analysis and Testing of Parallel Three-Phase-Inverters with A Novel Autonomous Current Sharing Controller

    DEFF Research Database (Denmark)

    Guan, Yajuan; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2015-01-01

    A novel simple and effective autonomous currentsharing controller for parallel three-phase inverters is employed in this paper. The novel controller is able to endow to the system high speed response and precision in contrast to the conventional droop control as it does not require calculating any...... active or reactive power, instead it uses a virtual impedance loop and a SFR phase-locked loop. The small-signal model of the system was developed for the autonomous operation of inverter-based microgrid with the proposed controller. The developed model shows large stability margin and fast transient...

  11. Proteomics and pathway analysis identifies JNK signaling as critical for high linear energy transfer radiation-induced apoptosis in non-small lung cancer cells.

    Science.gov (United States)

    Ståhl, Sara; Fung, Eva; Adams, Christopher; Lengqvist, Johan; Mörk, Birgitta; Stenerlöw, Bo; Lewensohn, Rolf; Lehtiö, Janne; Zubarev, Roman; Viktorsson, Kristina

    2009-05-01

    During the past decade, we have witnessed an explosive increase in generation of large proteomics data sets, not least in cancer research. There is a growing need to extract and correctly interpret information from such data sets to generate biologically relevant hypotheses. A pathway search engine (PSE) has recently been developed as a novel tool intended to meet these requirements. Ionizing radiation (IR) is an anticancer treatment modality that triggers multiple signal transduction networks. In this work, we show that high linear energy transfer (LET) IR induces apoptosis in a non-small cell lung cancer cell line, U-1810, whereas low LET IR does not. PSE was applied to study changes in pathway status between high and low LET IR to find pathway candidates of importance for high LET-induced apoptosis. Such pathways are potential clinical targets, and they were further validated in vitro. We used an unsupervised shotgun proteomics approach where high resolution mass spectrometry coupled to nanoflow liquid chromatography determined the identity and relative abundance of expressed proteins. Based on the proteomics data, PSE suggested the JNK pathway (p = 6.10(-6)) as a key event in response to high LET IR. In addition, the Fas pathway was found to be activated (p = 3.10(-5)) and the p38 pathway was found to be deactivated (p = 0.001) compared with untreated cells. Antibody-based analyses confirmed that high LET IR caused an increase in phosphorylation of JNK. Moreover pharmacological inhibition of JNK blocked high LET-induced apoptotic signaling. In contrast, neither an activation of p38 nor a role for p38 in high LET IR-induced apoptotic signaling was found. We conclude that, in contrast to conventional low LET IR, high LET IR can trigger activation of the JNK pathway, which in turn is critical for induction of apoptosis in these cells. Thus PSE predictions were largely confirmed, and PSE was proven to be a useful hypothesis-generating tool.

  12. CPSS: a computational platform for the analysis of small RNA deep sequencing data.

    Science.gov (United States)

    Zhang, Yuanwei; Xu, Bo; Yang, Yifan; Ban, Rongjun; Zhang, Huan; Jiang, Xiaohua; Cooke, Howard J; Xue, Yu; Shi, Qinghua

    2012-07-15

    Next generation sequencing (NGS) techniques have been widely used to document the small ribonucleic acids (RNAs) implicated in a variety of biological, physiological and pathological processes. An integrated computational tool is needed for handling and analysing the enormous datasets from small RNA deep sequencing approach. Herein, we present a novel web server, CPSS (a computational platform for the analysis of small RNA deep sequencing data), designed to completely annotate and functionally analyse microRNAs (miRNAs) from NGS data on one platform with a single data submission. Small RNA NGS data can be submitted to this server with analysis results being returned in two parts: (i) annotation analysis, which provides the most comprehensive analysis for small RNA transcriptome, including length distribution and genome mapping of sequencing reads, small RNA quantification, prediction of novel miRNAs, identification of differentially expressed miRNAs, piwi-interacting RNAs and other non-coding small RNAs between paired samples and detection of miRNA editing and modifications and (ii) functional analysis, including prediction of miRNA targeted genes by multiple tools, enrichment of gene ontology terms, signalling pathway involvement and protein-protein interaction analysis for the predicted genes. CPSS, a ready-to-use web server that integrates most functions of currently available bioinformatics tools, provides all the information wanted by the majority of users from small RNA deep sequencing datasets. CPSS is implemented in PHP/PERL+MySQL+R and can be freely accessed at http://mcg.ustc.edu.cn/db/cpss/index.html or http://mcg.ustc.edu.cn/sdap1/cpss/index.html.

  13. The NOD-like receptor signalling pathway in Helicobacter pylori infection and related gastric cancer: a case-control study and gene expression analyses.

    Directory of Open Access Journals (Sweden)

    Natalia Castaño-Rodríguez

    Full Text Available BACKGROUND: Currently, it is well established that cancer arises in chronically inflamed tissue. A number of NOD-like receptors (NLRs form inflammasomes, intracellular multiprotein complexes critical for generating mature pro-inflammatory cytokines (IL-1β and IL-18. As chronic inflammation of the gastric mucosa is a consequence of Helicobacter pylori infection, we investigated the role of genetic polymorphisms and expression of genes involved in the NLR signalling pathway in H. pylori infection and related gastric cancer (GC. MATERIALS AND METHODS: Fifty-one genetic polymorphisms were genotyped in 310 ethnic Chinese (87 non-cardia GC cases and 223 controls with functional dyspepsia. In addition, gene expression of 84 molecules involved in the NLR signalling pathway was assessed in THP-1 cells challenged with two H. pylori strains, GC026 (GC and 26695 (gastritis. RESULTS: CARD8-rs11672725, NLRP3-rs10754558, NLRP3-rs4612666, NLRP12-rs199475867 and NLRX1-rs10790286 showed significant associations with GC. On multivariate analysis, CARD8-rs11672725 remained a risk factor (OR: 4.80, 95% CI: 1.39-16.58. Further, NLRP12-rs2866112 increased the risk of H. pylori infection (OR: 2.13, 95% CI: 1.22-3.71. Statistical analyses assessing the joint effect of H. pylori infection and the selected polymorphisms revealed strong associations with GC (CARD8, NLRP3, CASP1 and NLRP12 polymorphisms. In gene expression analyses, five genes encoding NLRs were significantly regulated in H. pylori-challenged cells (NLRC4, NLRC5, NLRP9, NLRP12 and NLRX1. Interestingly, persistent up-regulation of NFKB1 with simultaneous down-regulation of NLRP12 and NLRX1 was observed in H. pylori GC026-challenged cells. Further, NF-κB target genes encoding pro-inflammatory cytokines, chemokines and molecules involved in carcinogenesis were markedly up-regulated in H. pylori GC026-challenged cells. CONCLUSIONS: Novel associations between polymorphisms in the NLR signalling pathway (CARD8

  14. Small hepatocellular carcinoma versus small cavernous hemangioma

    International Nuclear Information System (INIS)

    Choi, B.I.; Park, H.W.; Kim, S.H.; Han, M.C.; Kim, C.W.

    1989-01-01

    To determine the optimal pulse sequence for detection and differential diagnosis of small hepatocellular carcinomas and cavernous hemangiomas less than 5 cm in diameter, the authors have analyzed spin-echo (SE) images of 15 small hepatocellular carcinomas and 31 small cavernous hemangiomas obtained at 2.0 T. Pulse sequences used included repetition times (TRs) of 500 and 2,000 msec and echo times (TEs) of 30,60,90,120,150, and 180 msec. Mean tumor-liver contrast-to-noise ratios on the SE 2,000/60 (TR msec/TE msec) sequence were 23.90 ± 16.33 and 62.10 ± 25.94 for small hepatocellular carcinomas and hemangiomas, respectively, and were significantly greater than for all other pulse sequences. Mean tumor-liver signal intensity ratios on the SE 2,000/150 sequence were 2.34 ± 1.72 and 6.04 ± 2.72 for small hepatocellular carcinomas and hemangiomas, respectively, and were significantly greater than for all other pulse sequences in hemangiomas

  15. Small tyrosine kinase inhibitors interrupt EGFR signaling by interacting with erbB3 and erbB4 in glioblastoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco-Garcia, Estefania; Saceda, Miguel [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Unidad de Investigacion, Hospital General Universitario de Elche, 03203 Elche (Alicante) (Spain); Grasso, Silvina; Rocamora-Reverte, Lourdes; Conde, Mariano; Gomez-Martinez, Angeles [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Garcia-Morales, Pilar [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Unidad de Investigacion, Hospital General Universitario de Elche, 03203 Elche (Alicante) (Spain); Ferragut, Jose A. [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Martinez-Lacaci, Isabel, E-mail: imlacaci@umh.es [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Unidad AECC de Investigacion Traslacional en Cancer, Hospital Universitario Virgen de la Arrixaca, 30120 Murcia (Spain)

    2011-06-10

    Signaling through the epidermal growth factor receptor (EGFR) is relevant in glioblastoma. We have determined the effects of the EGFR inhibitor AG1478 in glioblastoma cell lines and found that U87 and LN-229 cells were very sensitive to this drug, since their proliferation diminished and underwent a marked G{sub 1} arrest. T98 cells were a little more refractory to growth inhibition and A172 cells did not undergo a G{sub 1} arrest. This G{sub 1} arrest was associated with up-regulation of p27{sup kip1}, whose protein turnover was stabilized. EGFR autophosphorylation was blocked with AG1478 to the same extent in all the cell lines. Other small-molecule EGFR tyrosine kinase inhibitors employed in the clinic, such as gefitinib, erlotinib and lapatinib, were able to abrogate proliferation of glioblastoma cell lines, which underwent a G{sub 1} arrest. However, the EGFR monoclonal antibody, cetuximab had no effect on cell proliferation and consistently, had no effect on cell cycle either. Similarly, cetuximab did not inhibit proliferation of U87 {Delta}EGFR cells or primary glioblastoma cell cultures, whereas small-molecule EGFR inhibitors did. Activity of downstream signaling molecules of EGFR such as Akt and especially ERK1/2 was interrupted with EGFR tyrosine kinase inhibitors, whereas cetuximab treatment could not sustain this blockade over time. Small-molecule EGFR inhibitors were able to prevent phosphorylation of erbB3 and erbB4, whereas cetuximab only hindered EGFR phosphorylation, suggesting that EGFR tyrosine kinase inhibitors may mediate their anti-proliferative effects through other erbB family members. We can conclude that small-molecule EGFR inhibitors may be a therapeutic approach for the treatment of glioblastoma patients.

  16. Progesterone receptor (PR) polyproline domain (PPD) mediates inhibition of epidermal growth factor receptor (EGFR) signaling in non-small cell lung cancer cells.

    Science.gov (United States)

    Kawprasertsri, Sornsawan; Pietras, Richard J; Marquez-Garban, Diana C; Boonyaratanakornkit, Viroj

    2016-05-01

    Recent evidence has suggested a possible role for progesterone receptor (PR) in the progression of non-small cell lung cancer (NSCLC). However, little is known concerning roles of PR in NSCLC. PR contains a polyproline domain (PPD), which directly binds to the SH3 domain of signaling molecules. Because PPD-SH3 interactions are essential for EGFR signaling, we hypothesized that the presence of PR-PPD interfered with EGFR-mediated signaling and cell proliferation. We examined the role of PR-PPD in cell proliferation and signaling by stably expressing PR-B, or PR-B with disrupting mutations in the PPD (PR-BΔSH3), from a tetracycline-regulated promoter in A549 NSCLC cells. PR-B dose-dependently inhibited cell growth in the absence of ligand, and progestin (R5020) treatment further suppressed the growth. Treatment with RU486 abolished PR-B- and R5020-mediated inhibition of cell proliferation. Expression of PR-BΔSH3 and treatment with R5020 or RU486 had no effect on cell proliferation. Furthermore, PR-B expression but not PR-BΔSH3 expression reduced EGF-induced A549 proliferation and activation of ERK1/2, in the absence of ligand. Taken together, our data demonstrated the significance of PR extranuclear signaling through PPD interactions in EGFR-mediated proliferation and signaling in NSCLC. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Signals and systems for dummies

    CERN Document Server

    Wickert, Mark

    2013-01-01

    Getting mixed signals in your signals and systems course? The concepts covered in a typical signals and systems course are often considered by engineering students to be some of the most difficult to master. Thankfully, Signals & Systems For Dummies is your intuitive guide to this tricky course, walking you step-by-step through some of the more complex theories and mathematical formulas in a way that is easy to understand. From Laplace Transforms to Fourier Analyses, Signals & Systems For Dummies explains in plain English the difficult concepts that can trip you up

  18. Nitrogen modulation of legume root architecture signalling pathways involves phytohormones and small regulatory molecules

    Directory of Open Access Journals (Sweden)

    Nadiatul Akmal Mohd-Radzman

    2013-10-01

    Full Text Available Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules.

  19. Nitrogen modulation of legume root architecture signaling pathways involves phytohormones and small regulatory molecules.

    Science.gov (United States)

    Mohd-Radzman, Nadiatul A; Djordjevic, Michael A; Imin, Nijat

    2013-10-01

    Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules.

  20. Identification of small molecule compounds that inhibit the HIF-1 signaling pathway

    Directory of Open Access Journals (Sweden)

    Sun Yi

    2009-12-01

    Full Text Available Abstract Background Hypoxia-inducible factor-1 (HIF-1 is the major hypoxia-regulated transcription factor that regulates cellular responses to low oxygen environments. HIF-1 is composed of two subunits: hypoxia-inducible HIF-1α and constitutively-expressed HIF-1β. During hypoxic conditions, HIF-1α heterodimerizes with HIF-1β and translocates to the nucleus where the HIF-1 complex binds to the hypoxia-response element (HRE and activates expression of target genes implicated in cell growth and survival. HIF-1α protein expression is elevated in many solid tumors, including those of the cervix and brain, where cells that are the greatest distance from blood vessels, and therefore the most hypoxic, express the highest levels of HIF-1α. Therapeutic blockade of the HIF-1 signaling pathway in cancer cells therefore provides an attractive strategy for development of anticancer drugs. To identify small molecule inhibitors of the HIF-1 pathway, we have developed a cell-based reporter gene assay and screened a large compound library by using a quantitative high-throughput screening (qHTS approach. Results The assay is based upon a β-lactamase reporter under the control of a HRE. We have screened approximate 73,000 compounds by qHTS, with each compound tested over a range of seven to fifteen concentrations. After qHTS we have rapidly identified three novel structural series of HIF-1 pathway Inhibitors. Selected compounds in these series were also confirmed as inhibitors in a HRE β-lactamase reporter gene assay induced by low oxygen and in a VEGF secretion assay. Three of the four selected compounds tested showed significant inhibition of hypoxia-induced HIF-1α accumulation by western blot analysis. Conclusion The use of β-lactamase reporter gene assays, in combination with qHTS, enabled the rapid identification and prioritization of inhibitors specific to the hypoxia induced signaling pathway.

  1. Evolution and Diversity of the Ras Superfamily of Small GTPases in Prokaryotes

    Science.gov (United States)

    Wuichet, Kristin; Søgaard-Andersen, Lotte

    2015-01-01

    The Ras superfamily of small GTPases are single domain nucleotide-dependent molecular switches that act as highly tuned regulators of complex signal transduction pathways. Originally identified in eukaryotes for their roles in fundamental cellular processes including proliferation, motility, polarity, nuclear transport, and vesicle transport, recent studies have revealed that single domain GTPases also control complex functions such as cell polarity, motility, predation, development and antibiotic resistance in bacteria. Here, we used a computational genomics approach to understand the abundance, diversity, and evolution of small GTPases in prokaryotes. We collected 520 small GTPase sequences present in 17% of 1,611 prokaryotic genomes analyzed that cover diverse lineages. We identified two discrete families of small GTPases in prokaryotes that show evidence of three distinct catalytic mechanisms. The MglA family includes MglA homologs, which are typically associated with the MglB GTPase activating protein, whereas members of the Rup (Ras superfamily GTPase of unknown function in prokaryotes) family are not predicted to interact with MglB homologs. System classification and genome context analyses support the involvement of small GTPases in diverse prokaryotic signal transduction pathways including two component systems, laying the foundation for future experimental characterization of these proteins. Phylogenetic analysis of prokaryotic and eukaryotic GTPases supports that the last universal common ancestor contained ancestral MglA and Rup family members. We propose that the MglA family was lost from the ancestral eukaryote and that the Ras superfamily members in extant eukaryotes are the result of vertical and horizontal gene transfer events of ancestral Rup GTPases. PMID:25480683

  2. Proteomics and Pathway Analysis Identifies JNK Signaling as Critical for High Linear Energy Transfer Radiation-induced Apoptosis in Non-small Lung Cancer Cells*S⃞

    Science.gov (United States)

    Ståhl, Sara; Fung, Eva; Adams, Christopher; Lengqvist, Johan; Mörk, Birgitta; Stenerlöw, Bo; Lewensohn, Rolf; Lehtiö, Janne; Zubarev, Roman; Viktorsson, Kristina

    2009-01-01

    During the past decade, we have witnessed an explosive increase in generation of large proteomics data sets, not least in cancer research. There is a growing need to extract and correctly interpret information from such data sets to generate biologically relevant hypotheses. A pathway search engine (PSE) has recently been developed as a novel tool intended to meet these requirements. Ionizing radiation (IR) is an anticancer treatment modality that triggers multiple signal transduction networks. In this work, we show that high linear energy transfer (LET) IR induces apoptosis in a non-small cell lung cancer cell line, U-1810, whereas low LET IR does not. PSE was applied to study changes in pathway status between high and low LET IR to find pathway candidates of importance for high LET-induced apoptosis. Such pathways are potential clinical targets, and they were further validated in vitro. We used an unsupervised shotgun proteomics approach where high resolution mass spectrometry coupled to nanoflow liquid chromatography determined the identity and relative abundance of expressed proteins. Based on the proteomics data, PSE suggested the JNK pathway (p = 6·10−6) as a key event in response to high LET IR. In addition, the Fas pathway was found to be activated (p = 3·10−5) and the p38 pathway was found to be deactivated (p = 0.001) compared with untreated cells. Antibody-based analyses confirmed that high LET IR caused an increase in phosphorylation of JNK. Moreover pharmacological inhibition of JNK blocked high LET-induced apoptotic signaling. In contrast, neither an activation of p38 nor a role for p38 in high LET IR-induced apoptotic signaling was found. We conclude that, in contrast to conventional low LET IR, high LET IR can trigger activation of the JNK pathway, which in turn is critical for induction of apoptosis in these cells. Thus PSE predictions were largely confirmed, and PSE was proven to be a useful hypothesis-generating tool. PMID:19168796

  3. Signal processing for boiling noise detection

    International Nuclear Information System (INIS)

    Ledwidge, T.J.; Black, J.L.

    1989-01-01

    The present paper deals with investigations of acoustic signals from a boiling experiment performed on the KNS I loop at KfK Karlsruhe. Signals have been analysed in frequency as well as in time domain. Signal characteristics successfully used to detect the boiling process have been found in time domain. (author). 6 refs, figs

  4. Compositional analyses of small lunar pyroclastic deposits using Clementine multispectral data

    Science.gov (United States)

    Gaddis, L.R.; Hawke, B.R.; Robinson, M.S.; Coombs, C.

    2000-01-01

    Clementine ultraviolet-visible (UVVIS) data are used to examine the compositions of 18 pyroclastic deposits (15 small, three large) at 13 sites on the Moon. Compositional variations among pyroclastic deposits largely result from differing amounts of new basaltic (or juvenile) material and reworked local material entrained in their ejecta upon eruption. Characterization of pyroclastic deposit compositions allows us to understand the mechanisms of lunar explosive volcanism. Evidence for compositional differences between small pyroclastic deposits at a single site is observed at Atlas crater. At all sites, compositional variation among the small pyroclastic deposits is consistent with earlier classification based on Earth-based spectra: three compositional groups can be observed, and the trend of increasing mafic absorption band strength from Group 1 to Group 2 to Group 3 is noted. As redefined here, Group 1 deposits include those of Alphonsus West, Alphonsus Southeast, Alphonsus Northeast 2, Atlas South, Crüger, Franklin, Grimaldi, Lavoisier, Oppenheimer, Orientale, and Riccioli. Group 1 deposits resemble lunar highlands, with weak mafic bands and relatively high UV/VIS ratios. Group 2 deposits include those of Alphonsus Northeast 1, Atlas North, Eastern Frigoris East and West, and Aristarchus Plateau; Group 2 deposits are similar to mature lunar maria, with moderate mafic band depths and intermediate UV/VIS ratios. The single Group 3 deposit, J. Herschel, has a relatively strong mafic band and a low UV/VIS ratio, and olivine is a likely juvenile component. Two of the deposits in these groups, Orientale and Aristarchus, are large pyroclastic deposits. The third large pyroclastic deposit, Apollo 17/Taurus Littrow, has a very weak mafic band and a high UV/VIS ratio and it does not belong to any of the compositional groups for small pyroclastic deposits. The observed compositional variations indicate that highland and mare materials are also present in many large and

  5. Mutational analyses of the signals involved in the subcellular location of DSCR1

    Directory of Open Access Journals (Sweden)

    Henrique-Silva Flávio

    2002-09-01

    Full Text Available Abstract Background Down syndrome is the most frequent genetic disorder in humans. Rare cases involving partial trisomy of chromosome 21 allowed a small chromosomal region common to all carriers, called Down Syndrome Critical Region (DSCR, to be determined. The DSCR1 gene was identified in this region and is expressed preferentially in the brain, heart and skeletal muscle. Recent studies have shown that DSCR1 belongs to a family of proteins that binds and inhibits calcineurin, a serine-threonine phosphatase. The work reported on herein consisted of a study of the subcellular location of DSCR1 and DSCR1-mutated forms by fusion with a green fluorescent protein, using various cell lines, including human. Results The protein's location was preferentially nuclear, independently of the isoform, cell line and insertion in the GFP's N- or C-terminal. A segment in the C-terminal, which is important in the location of the protein, was identified by deletion. On the other hand, site-directed mutational analyses have indicated the involvement of some serine and threonine residues in this event. Conclusion In this paper, we discuss the identification of amino acids which can be important for subcellular location of DSCR1. The involvement of residues that are prone to phosphorylation suggests that the location and function of DSCR1 may be regulated by kinases and/or phosphatases.

  6. Role of Translocted Signals in Regulating Root Development and Nutrient Uptake in Legumes

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, C. A. [School of Plant Biology, University of Western Australia, Crawley, WA (Australia)

    2013-11-15

    Uptake of nutrients is achieved through the expression and activity of specific carrier/transporter mechanisms localized in the root system and distributed as a consequence of the development of the architecture of the system. Both root system development and the nutrient transport mechanisms are responsive to environmental factors that include nutrient supply and availability, water supply, salinity, soil acidity and compaction together with a wide range of biotic stresses. The response to each may be regulated at the molecular level by both local and systemic signals. These signals include the classical plant growth regulators but also low molecular weight compounds such as sugars and amino acids as well as macromolecules, including peptides, proteins and nucleic acids. Among the latter, recent research has shown that small RNA species and especially small interfering RNAs (siRNA) and microRNAs (miRNA) are potent and effective regulators of gene expression which, in the context of root development as well as nutrient uptake, have central and critical roles. Systemic (translocated) signals that specifically regulate root development and function are less well defined but analyses of phloem exudate in species of lupin (Lupinus albus and L. angustifolius) and species of Brassica and cucurbits have demonstrated that a wide range of macromolecules, including miRNAs, are present and potentially translocated from source organs (principally leaves) to sinks (shoot apical meristems, developing fruits and seeds, roots and nodules). While specific signaling roles for many of these macromolecules are yet to be discovered there are some that have been documented and their regulatory activity in organ development and functioning, as well as in nutrition, confirmed. The following article provides an up to date review and presents the results of recent research using lupin with emphasis on the analysis of small RNAs and their likely role(s) in regulation of root development and

  7. Distortions in the output signals of conventional spectrum analyzers

    International Nuclear Information System (INIS)

    Njau, E.C.

    1988-08-01

    We show that the output signals of conventional spectrum analysers contain distortions which basically originate from the signal processing performed inside the analysers' frequency convertors. Total elimination of these distortions through normal filtering techniques is difficult owing to the closeness of some of their frequencies to the corresponding frequencies of the required signals. Simple design adjustments that can minimize these distortions are suggested. (author). 7 refs, 2 figs

  8. Analysis of the nuclear localization signal of TRF1 in non-small cell lung cancer

    Directory of Open Access Journals (Sweden)

    HU JIAN

    2009-01-01

    Full Text Available Several studies revealed a similar down-regulation of telomeric repeat binding factor 1 (TRF1 in tumors. We have previously reported the TRFl expression levels were down-regulation in non-small cell lung cancer (NSCLC. The regulation of TRFl localization is proposed to be important for the function and expression. The nuclear localization signal (NLS and nuclear export signal (NES are often important clues to localization of protein. The objective of the present study was to investigate the NLS and NES of TRFl in NSCLC patients. Thirty (30 patients with NSCLCs had undergone radical operations in The First Affiliated Hospital, College of Medicine, Zhejiang University. DNA sequences of NLSs and NESs were amplified by PCR. The PCR products were analyzed by DNA sequencing. There were four NLSs of the TRFl protein, including two monopartite and two bipartite NLSs. The NLSs sequences were included in 337KKERRVGTPQSTKKKKESRR356. The exon 8 and exon 9 of TRFl DNA were covered the NLS sequences. The sequences of predicted NESs were 11WMLDFLCLSL86 and 174NLLKLQALAV183, respectively. The exon 1, exon 3 and exon 4 of TRFl were covered the NES sequences. In NSCLCs, there was no a mutation, deletion, or substitution in NLS and NES of TRFl. We conclude that the NLS and NES sequences in NSCLCs patients did not have mutations. Down-expression of TRFl does not indicate gene mutation of NLS and NES in NSCLCs.

  9. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating......The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  10. DBDA as a Novel Matrix for the Analyses of Small Molecules and Quantification of Fatty Acids by Negative Ion MALDI-TOF MS.

    Science.gov (United States)

    Ling, Ling; Li, Ying; Wang, Sheng; Guo, Liming; Xiao, Chunsheng; Chen, Xuesi; Guo, Xinhua

    2018-04-01

    Matrix interference ions in low mass range has always been a concern when using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze small molecules (matrix, N1,N4-dibenzylidenebenzene-1,4-diamine (DBDA) was synthesized for the analyses of small molecules by negative ion MALDI-TOF MS. Notably, only neat ions ([M-H] - ) of fatty acids without matrix interference appeared in the mass spectra and the limit of detection (LOD) reached 0.3 fmol. DBDA also has great performance towards other small molecules such as amino acids, peptides, and nucleotide. Furthermore, with this novel matrix, the free fatty acids in serum were quantitatively analyzed based on the correlation curves with correlation coefficient of 0.99. In addition, UV-Vis experiments and molecular orbital calculations were performed to explore mechanism about DBDA used as matrix in the negative ion mode. The present work shows that the DBDA matrix is a highly sensitive matrix with few interference ions for analysis of small molecules. Meanwhile, DBDA is able to precisely quantify the fatty acids in real biological samples. Graphical Abstract ᅟ.

  11. Patient Safety Outcomes in Small Urban and Small Rural Hospitals

    Science.gov (United States)

    Vartak, Smruti; Ward, Marcia M.; Vaughn, Thomas E.

    2010-01-01

    Purpose: To assess patient safety outcomes in small urban and small rural hospitals and to examine the relationship of hospital and patient factors to patient safety outcomes. Methods: The Nationwide Inpatient Sample and American Hospital Association annual survey data were used for analyses. To increase comparability, the study sample was…

  12. A generalizable platform for interrogating target- and signal-specific consequences of electrophilic modifications in redox-dependent cell signaling.

    Science.gov (United States)

    Lin, Hong-Yu; Haegele, Joseph A; Disare, Michael T; Lin, Qishan; Aye, Yimon

    2015-05-20

    Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized "electrophile toolbox" with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology, T-REX (targetable reactive electrophiles and oxidants), is established by (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept, which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein, one of several redox-sensitive regulators of the Nrf2-ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2-ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background.

  13. FEL small signal dynamics and electron beam prebunching

    International Nuclear Information System (INIS)

    Dattoli, G.

    1993-01-01

    A seed signal and/or a pre-bunched electron beam may provide the start up of a free electron laser (FEL). Recently, interest has grown around FEL's operating with pre-bunched electron beams; this paper is, therefore, devoted to the analysis of the dynamic features of FEL's operating in such a configuration. It exploits a slightly modified form of the FEL high gain equation to derive quantities of practical interest like the dependence of the system growth rate on the bunching coefficients

  14. Signal Formation Processes in Micromegas Detectors and Quality Control for large size Detector Construction for the ATLAS New Small Wheel

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00387450; Rembser, Christoph

    2017-08-04

    The Micromegas technology is one of the most successful modern gaseous detector concepts and widely utilized in nuclear and particle physics experiments. Twenty years of R & D rendered the technology sufficiently mature to be selected as precision tracking detector for the New Small Wheel (NSW) upgrade of the ATLAS Muon spectrometer. This will be the first large scale application of Micromegas in one of the major LHC experiments. However, many of the fundamental microscopic processes in these gaseous detectors are still not fully understood and studies on several detector aspects, like the micromesh geometry, have never been addressed systematically. The studies on signal formation in Micromegas, presented in the first part of this thesis, focuses on the microscopic signal electron loss mechanisms and the amplification processes in electron gas interaction. Based on a detailed model of detector parameter dependencies, these processes are scrutinized in an iterating comparison between exper- imental result...

  15. Magnetoelectric coupling study in multiferroic Pb(Fe0.5Nb0.5)O3 ceramics through small and large electric signal standard measurements

    International Nuclear Information System (INIS)

    Raymond, Oscar; Siqueiros, Jesus M.; Font, Reynaldo; Portelles, Jorge

    2011-01-01

    Multifunctional multiferroic materials such as the single phase compound Pb(Fe 0.5 Nb 0.5 )O 3 (PFN), where ferroelectric and antiferromagnetic order coexist, are very promising and have great interest from the academic and technological points of view. In this work, coupling of the ferroelectric and magnetic moments is reported. For this study, a combination of the small signal response using the impedance spectroscopy technique and the electromechanical resonance method with the large signal response through standard ferroelectric hysteresis measurement, has been used with and without an applied magnetic field. The measurements to determine the electrical properties of the ceramic were performed as functions of the bias and poling electric fields. A simultaneous analysis of the complex dielectric constant ε-tilde, impedance Z-tilde, electric modulus M-tilde, admittance Y-tilde, and the electromechanical parameters and coupling factors is presented. The results are correlated with a previous study of structural, morphological, small signal dielectric frequency-temperature response, and the ferroelectric hysteretic, magnetic and magnetodielectric behaviors. The observed shifts of the resonance and antiresonance frequency values can be associated with change of the ferroelectric domain size favored by the readjustment of the oxygen octahedron when the magnetic field is applied. From P-E hysteresis loops obtained without and with an external applied magnetic field, a dc magnetoelectric coupling effect with maximum value of 4 kV/cm T (400 mV/cm Oe) was obtained.

  16. Melittin exerts an antitumor effect on non‑small cell lung cancer cells.

    Science.gov (United States)

    Zhang, Su-Fang; Chen, Zhe

    2017-09-01

    Lung cancer accounts for a significant percentage of all cancer‑associated mortalities in men and women, with non‑small cell lung cancer being the most frequently occurring type of lung cancer. Melittin is the principal active component of apitoxin (bee venom) that has been reported to exert anti‑chronic inflammatory and anti‑cancer effects. In the present study, the antitumor effect of melittin was evaluated using in vivo and in vitro analyses. The results demonstrated that melittin significantly inhibited the epidermal growth factor‑induced invasion and migration of non‑small cell lung cancer cells. Subcutaneous injection of melittin at doses of 1 and 10 mg/kg significantly suppressed non‑small cell lung cancer tumor growth by 27 and 61%, respectively. In addition, melittin significantly inhibited the secretion of vascular endothelial growth factor (VEGF) in non‑small cell lung cancer cells. Furthermore, melittin decreased the protein expression of VEGF and hypoxia‑inducible factor 1‑α. Therefore, the antitumor activity of melittin may be associated with the anti‑angiogenic actions of inhibiting the VEGF and hypoxia‑inducible factor signaling pathways.

  17. Honey Bee Inhibitory Signaling Is Tuned to Threat Severity and Can Act as a Colony Alarm Signal.

    Science.gov (United States)

    Tan, Ken; Dong, Shihao; Li, Xinyu; Liu, Xiwen; Wang, Chao; Li, Jianjun; Nieh, James C

    2016-03-01

    Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world's largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon foragers and nests of the Asian honey bee, Apis cerana. We attacked foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that, like Apis mellifera, A. cerana possesses a vibrational "stop signal," which can be triggered by predator attacks upon foragers and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS large hornet) had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS small hornet) and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS nest) were produced by foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon foragers (SS forager). Unlike SS forager, SS nest were targeted at dancing and non-dancing foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by the bee alarm pheromone and live hornet presence to heat-ball the hornet. In A. cerana, sophisticated recruitment communication that encodes food location, the waggle dance, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level.

  18. Signaling aggression.

    Science.gov (United States)

    van Staaden, Moira J; Searcy, William A; Hanlon, Roger T

    2011-01-01

    From psychological and sociological standpoints, aggression is regarded as intentional behavior aimed at inflicting pain and manifested by hostility and attacking behaviors. In contrast, biologists define aggression as behavior associated with attack or escalation toward attack, omitting any stipulation about intentions and goals. Certain animal signals are strongly associated with escalation toward attack and have the same function as physical attack in intimidating opponents and winning contests, and ethologists therefore consider them an integral part of aggressive behavior. Aggressive signals have been molded by evolution to make them ever more effective in mediating interactions between the contestants. Early theoretical analyses of aggressive signaling suggested that signals could never be honest about fighting ability or aggressive intentions because weak individuals would exaggerate such signals whenever they were effective in influencing the behavior of opponents. More recent game theory models, however, demonstrate that given the right costs and constraints, aggressive signals are both reliable about strength and intentions and effective in influencing contest outcomes. Here, we review the role of signaling in lieu of physical violence, considering threat displays from an ethological perspective as an adaptive outcome of evolutionary selection pressures. Fighting prowess is conveyed by performance signals whose production is constrained by physical ability and thus limited to just some individuals, whereas aggressive intent is encoded in strategic signals that all signalers are able to produce. We illustrate recent advances in the study of aggressive signaling with case studies of charismatic taxa that employ a range of sensory modalities, viz. visual and chemical signaling in cephalopod behavior, and indicators of aggressive intent in the territorial calls of songbirds. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Unique players in the BMP pathway: Small C-terminal domain phosphatases dephosphorylate Smad1 to attenuate BMP signaling

    Science.gov (United States)

    Knockaert, Marie; Sapkota, Gopal; Alarcón, Claudio; Massagué, Joan; Brivanlou, Ali H.

    2006-01-01

    Smad transcription factors are key signal transducers for the TGF-β/bone morphogenetic protein (BMP) family of cytokines and morphogens. C-terminal serine phosphorylation by TGF-β and BMP membrane receptors drives Smads into the nucleus as transcriptional regulators. Dephosphorylation and recycling of activated Smads is an integral part of this process, which is critical for agonist sensing by the cell. However, the nuclear phosphatases involved have remained unknown. Here we provide functional, biochemical, and embryological evidence identifying the SCP (small C-terminal domain phosphatase) family of nuclear phosphatases as mediators of Smad1 dephosphorylation in the BMP signaling pathway in vertebrates. Xenopus SCP2/Os4 inhibits BMP activity in the presumptive ectoderm and leads to neuralization. In Xenopus embryos, SCP2/Os4 and human SCP1, 2, and 3 cause selective dephosphorylation of Smad1 compared with Smad2, inhibiting BMP- and Smad1-dependent transcription and leading to the induction of the secondary dorsal axis. In human cells, RNAi-mediated depletion of SCP1 and SCP2 increases the extent and duration of Smad1 phosphorylation in response to BMP, the transcriptional action of Smad1, and the strength of endogenous BMP gene responses. The present identification of the SCP family as Smad C-terminal phosphatases sheds light on the events that attenuate Smad signaling and reveals unexpected links to the essential phosphatases that control RNA polymerase II in eukaryotes. PMID:16882717

  20. Acoustic signalling in a small, socially monogamous canid

    DEFF Research Database (Denmark)

    Darden, Safi-Kirstine; Dabelsteen, Torben

    2008-01-01

    Animals that actively defend all or part of their home range for the exclusive use of members of their social group are considered territorial. Defended areas may contain resources such as dens or nests, key foraging sites, or sexual partners that vary in value by season. We investigated territor....... These results suggest that the barking sequence is used in territorial defence and we conclude that at least male swift foxes are territorial in the mating season and they use a long-ranging acoustic signal in territory defence....

  1. Duplicate retention in signalling proteins and constraints from network dynamics.

    Science.gov (United States)

    Soyer, O S; Creevey, C J

    2010-11-01

    Duplications are a major driving force behind evolution. Most duplicates are believed to fix through genetic drift, but it is not clear whether this process affects all duplications equally or whether there are certain gene families that are expected to show neutral expansions under certain circumstances. Here, we analyse the neutrality of duplications in different functional classes of signalling proteins based on their effects on response dynamics. We find that duplications involving intermediary proteins in a signalling network are neutral more often than those involving receptors. Although the fraction of neutral duplications in all functional classes increase with decreasing population size and selective pressure on dynamics, this effect is most pronounced for receptors, indicating a possible expansion of receptors in species with small population size. In line with such an expectation, we found a statistically significant increase in the number of receptors as a fraction of genome size in eukaryotes compared with prokaryotes. Although not confirmative, these results indicate that neutral processes can be a significant factor in shaping signalling networks and affect proteins from different functional classes differently. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

  2. Method for Measuring Small Nonlinearities of Electric Characteristics

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom; Meyer, Niels I; Schjær-Jacobsen, Jørgen

    1965-01-01

    A method is described for measuring very small deviations from linearity in electric characteristics. The measurement is based on the harmonics generated by the nonlinear element when subjected to a sine wave signal. A special bridge circuit is used to balance out the undesired harmonics...... of the signal generator together with the first harmonic frequency. The set-up measures the small-signal value and the first and second derivative with respect to voltage. The detailed circuits are given for measuring nonlinearities in Ohmic and capacitive components. In the Ohmic case, a sensitivity...

  3. Small leucine rich proteoglycan family regulates multiple signalling pathways in neural development and maintenance.

    Science.gov (United States)

    Dellett, Margaret; Hu, Wanzhou; Papadaki, Vasiliki; Ohnuma, Shin-ichi

    2012-04-01

    The small leucine-rich repeat proteoglycan (SLRPs) family of proteins currently consists of five classes, based on their structural composition and chromosomal location. As biologically active components of the extracellular matrix (ECM), SLRPs were known to bind to various collagens, having a role in regulating fibril assembly, organization and degradation. More recently, as a function of their diverse proteins cores and glycosaminoglycan side chains, SLRPs have been shown to be able to bind various cell surface receptors, growth factors, cytokines and other ECM components resulting in the ability to influence various cellular functions. Their involvement in several signaling pathways such as Wnt, transforming growth factor-β and epidermal growth factor receptor also highlights their role as matricellular proteins. SLRP family members are expressed during neural development and in adult neural tissues, including ocular tissues. This review focuses on describing SLRP family members involvement in neural development with a brief summary of their role in non-neural ocular tissues and in response to neural injury. © 2012 The Authors Development, Growth & Differentiation © 2012 Japanese Society of Developmental Biologists.

  4. Elemental abundance and analyses with coadded DAO spectrograms

    International Nuclear Information System (INIS)

    Adelman, S.J.

    1987-01-01

    One can improve the quality of elemental abundance analyses by using higher signal-to-noise data than has been the practice at high resolution. The procedures developed at the Dominion Astrophysical Observatory to coadd high-dispersion coude spectrograms are used with a minimum of 10 6.5 A mm -1 IIa-O spectrograms of each of three field horizontal-branch (FHB)A stars to increase the signal-to-noise ratio of the photographic data over a considerable wavelength region. Fine analyses of the sharp-lined prototype FHB stars HD 109995 and 161817 show an internal consistency which justifies this effort. Their photospheric elemental abundances are similar to those of Population II globular cluster giants. (author)

  5. Small signal modulation characteristics of red-emitting (λ = 610 nm) III-nitride nanowire array lasers on (001) silicon

    KAUST Repository

    Jahangir, Shafat; Frost, Thomas; Hazari, Arnab; Yan, Lifan; Stark, Ethan; LaMountain, Trevor; Millunchick, Joanna M.; Ooi, Boon S.; Bhattacharya, Pallab

    2015-01-01

    The small signal modulation characteristics of an InGaN/GaN nanowire array edge- emitting laser on (001) silicon are reported. The emission wavelength is 610 nm. Lattice matched InAlN cladding layers were incorporated in the laser heterostructure for better mode confinement. The suitability of the nanowire lasers for use in plastic fiber communication systems with direct modulation is demonstrated through their modulation bandwidth of f-3dB,max = 3.1 GHz, very low values of chirp (0.8 Å) and α-parameter, and large differential gain (3.1 × 10-17 cm2).

  6. Small signal modulation characteristics of red-emitting (λ = 610 nm) III-nitride nanowire array lasers on (001) silicon

    KAUST Repository

    Jahangir, Shafat

    2015-02-16

    The small signal modulation characteristics of an InGaN/GaN nanowire array edge- emitting laser on (001) silicon are reported. The emission wavelength is 610 nm. Lattice matched InAlN cladding layers were incorporated in the laser heterostructure for better mode confinement. The suitability of the nanowire lasers for use in plastic fiber communication systems with direct modulation is demonstrated through their modulation bandwidth of f-3dB,max = 3.1 GHz, very low values of chirp (0.8 Å) and α-parameter, and large differential gain (3.1 × 10-17 cm2).

  7. Honey Bee Inhibitory Signaling Is Tuned to Threat Severity and Can Act as a Colony Alarm Signal.

    Directory of Open Access Journals (Sweden)

    Ken Tan

    2016-03-01

    Full Text Available Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world's largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon foragers and nests of the Asian honey bee, Apis cerana. We attacked foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that, like Apis mellifera, A. cerana possesses a vibrational "stop signal," which can be triggered by predator attacks upon foragers and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS large hornet had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS small hornet and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS nest were produced by foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon foragers (SS forager. Unlike SS forager, SS nest were targeted at dancing and non-dancing foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by the bee alarm pheromone and live hornet presence to heat-ball the hornet. In A. cerana, sophisticated recruitment communication that encodes food location, the waggle dance, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level.

  8. Application of pattern recognition technique on randon signals for automatic monitoring of dynamic systems with emphasis on nuclear reactors

    International Nuclear Information System (INIS)

    Nascimento, J.A. do.

    1981-01-01

    The time varying or noise component of dynamic system parameters contains information on the system state. Pattern recognition analysis of noise signals for such systems is a powerful technique for assessing 'system normality' or 'correct operation'. Data analysis with modern small computers enables the otherwise unmanageable volumes of data to be processed on line and the results presented in a meaningful form. These informations provide necessary data for maintaining the system at optimum operating conditions. An automatic pattern recognition program, PSDREC, developmed for the surveillance of nuclear reactor and rotating machinery is described, and the relevant theory is outlined. This program, which applies 8 statistical tests to calculated power spectral density (PSD) distributions, was earlier installed in a PDP-11/45 computer at IPEN. In this work it has been used to separately analyse recorded signals from three systems, namely an operational BWR power reactor (neutron signals), a water pump and a diesel motor (vibration signals). The latter two were, respectively, operated over a wide-range of flow and load conditions. The statistical tests were applied to frequency bands of (0,1-40) Hz, (0-1000) Hz and (0,20000) Hz. for the BWR, pump and diesel signal data, respectively. Operation and analysis conditions are given together with representative graphs of the analysed PSD distributions. Results of the tests - discussed in some detail - are considered to be satisfactory. (Author) [pt

  9. small signal analysis of load angle governing and excitation control

    African Journals Online (AJOL)

    Dr Obe

    system stabilizers (PSS) or using terminal voltage for control of exciter and speed signal for governor. ... Vfd= generator field voltage. Xd, Xq ... each other in the frequency domain, and therefore ..... angle sensing equipment, relays and.

  10. Novel penalised likelihood reconstruction of PET in the assessment of histologically verified small pulmonary nodules

    International Nuclear Information System (INIS)

    Teoh, Eugene J.; Gleeson, Fergus V.; McGowan, Daniel R.; Bradley, Kevin M.; Belcher, Elizabeth; Black, Edward

    2016-01-01

    Investigate the effect of a novel Bayesian penalised likelihood (BPL) reconstruction algorithm on analysis of pulmonary nodules examined with 18F-FDG PET/CT, and to determine its effect on small, sub-10-mm nodules. 18F-FDG PET/CTs performed for nodule evaluation in 104 patients (121 nodules) were retrospectively reconstructed using the new algorithm, and compared to time-of-flight ordered subset expectation maximisation (OSEM) reconstruction. Nodule and background parameters were analysed semi-quantitatively and visually. BPL compared to OSEM resulted in statistically significant increases in nodule SUV max (mean 5.3 to 8.1, p < 0.00001), signal-to-background (mean 3.6 to 5.3, p < 0.00001) and signal-to-noise (mean 24 to 41, p < 0.00001). Mean percentage increase in SUV max (%ΔSUV max ) was significantly higher in nodules ≤10 mm (n = 31, mean 73 %) compared to >10 mm (n = 90, mean 42 %) (p = 0.025). Increase in signal-to-noise was higher in nodules ≤10 mm (224 %, mean 12 to 27) compared to >10 mm (165 %, mean 28 to 46). When applying optimum SUV max thresholds for detecting malignancy, the sensitivity and accuracy increased using BPL, with the greatest improvements in nodules ≤10 mm. BPL results in a significant increase in signal-to-background and signal-to-noise compared to OSEM. When semi-quantitative analyses to diagnose malignancy are applied, higher SUV max thresholds may be warranted owing to the SUV max increase compared to OSEM. (orig.)

  11. Novel penalised likelihood reconstruction of PET in the assessment of histologically verified small pulmonary nodules

    Energy Technology Data Exchange (ETDEWEB)

    Teoh, Eugene J.; Gleeson, Fergus V. [Oxford University Hospitals NHS Trust, Department of Radiology, Churchill Hospital, Oxford (United Kingdom); University of Oxford, Department of Oncology, Oxford (United Kingdom); McGowan, Daniel R. [University of Oxford, Department of Oncology, Oxford (United Kingdom); Oxford University Hospitals NHS Trust, Radiation Physics and Protection, Churchill Hospital, Oxford (United Kingdom); Bradley, Kevin M. [Oxford University Hospitals NHS Trust, Department of Radiology, Churchill Hospital, Oxford (United Kingdom); Belcher, Elizabeth; Black, Edward [Oxford University Hospitals NHS Trust, Department of Thoracic Surgery, John Radcliffe Hospital, Oxford (United Kingdom)

    2016-02-15

    Investigate the effect of a novel Bayesian penalised likelihood (BPL) reconstruction algorithm on analysis of pulmonary nodules examined with 18F-FDG PET/CT, and to determine its effect on small, sub-10-mm nodules. 18F-FDG PET/CTs performed for nodule evaluation in 104 patients (121 nodules) were retrospectively reconstructed using the new algorithm, and compared to time-of-flight ordered subset expectation maximisation (OSEM) reconstruction. Nodule and background parameters were analysed semi-quantitatively and visually. BPL compared to OSEM resulted in statistically significant increases in nodule SUV{sub max} (mean 5.3 to 8.1, p < 0.00001), signal-to-background (mean 3.6 to 5.3, p < 0.00001) and signal-to-noise (mean 24 to 41, p < 0.00001). Mean percentage increase in SUV{sub max} (%ΔSUV{sub max}) was significantly higher in nodules ≤10 mm (n = 31, mean 73 %) compared to >10 mm (n = 90, mean 42 %) (p = 0.025). Increase in signal-to-noise was higher in nodules ≤10 mm (224 %, mean 12 to 27) compared to >10 mm (165 %, mean 28 to 46). When applying optimum SUV{sub max} thresholds for detecting malignancy, the sensitivity and accuracy increased using BPL, with the greatest improvements in nodules ≤10 mm. BPL results in a significant increase in signal-to-background and signal-to-noise compared to OSEM. When semi-quantitative analyses to diagnose malignancy are applied, higher SUV{sub max} thresholds may be warranted owing to the SUV{sub max} increase compared to OSEM. (orig.)

  12. Performance Comparison of Adaptive Estimation Techniques for Power System Small-Signal Stability Assessment

    Directory of Open Access Journals (Sweden)

    E. A. Feilat

    2010-12-01

    Full Text Available This paper demonstrates the assessment of the small-signal stability of a single-machine infinite- bus power system under widely varying loading conditions using the concept of synchronizing and damping torques coefficients. The coefficients are calculated from the time responses of the rotor angle, speed, and torque of the synchronous generator. Three adaptive computation algorithms including Kalman filtering, Adaline, and recursive least squares have been compared to estimate the synchronizing and damping torque coefficients. The steady-state performance of the three adaptive techniques is compared with the conventional static least squares technique by conducting computer simulations at different loading conditions. The algorithms are compared to each other in terms of speed of convergence and accuracy. The recursive least squares estimation offers several advantages including significant reduction in computing time and computational complexity. The tendency of an unsupplemented static exciter to degrade the system damping for medium and heavy loading is verified. Consequently, a power system stabilizer whose parameters are adjusted to compensate for variations in the system loading is designed using phase compensation method. The effectiveness of the stabilizer in enhancing the dynamic stability over wide range of operating conditions is verified through the calculation of the synchronizing and damping torque coefficients using recursive least square technique.

  13. Bioinformatics Analyses of the Role of Vascular Endothelial Growth Factor in Patients with Non-Small Cell Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Ying Wang

    Full Text Available This study was aimed to identify the expression pattern of vascular endothelial growth factor (VEGF in non-small cell lung cancer (NSCLC and to explore its potential correlation with the progression of NSCLC.Gene expression profile GSE39345 was downloaded from the Gene Expression Omnibus database. Twenty healthy controls and 32 NSCLC samples before chemotherapy were analyzed to identify the differentially expressed genes (DEGs. Then pathway enrichment analysis of the DEGs was performed and protein-protein interaction networks were constructed. Particularly, VEGF genes and the VEGF signaling pathway were analyzed. The sub-network was constructed followed by functional enrichment analysis.Total 1666 up-regulated and 1542 down-regulated DEGs were identified. The down-regulated DEGs were mainly enriched in the pathways associated with cancer. VEGFA and VEGFB were found to be the initiating factor of VEGF signaling pathway. In addition, in the epidermal growth factor receptor (EGFR, VEGFA and VEGFB associated sub-network, kinase insert domain receptor (KDR, fibronectin 1 (FN1, transforming growth factor beta induced (TGFBI and proliferating cell nuclear antigen (PCNA were found to interact with at least two of the three hub genes. The DEGs in this sub-network were mainly enriched in Gene Ontology terms related to cell proliferation.EGFR, KDR, FN1, TGFBI and PCNA may interact with VEGFA to play important roles in NSCLC tumorigenesis. These genes and corresponding proteins may have the potential to be used as the targets for either diagnosis or treatment of patients with NSCLC.

  14. Using analyses of amino Acid coevolution to understand protein structure and function.

    Science.gov (United States)

    Ashenberg, Orr; Laub, Michael T

    2013-01-01

    Determining which residues of a protein contribute to a specific function is a difficult problem. Analyses of amino acid covariation within a protein family can serve as a useful guide by identifying residues that are functionally coupled. Covariation analyses have been successfully used on several different protein families to identify residues that work together to promote folding, enable protein-protein interactions, or contribute to an enzymatic activity. Covariation is a statistical signal that can be measured in a multiple sequence alignment of homologous proteins. As sequence databases have expanded dramatically, covariation analyses have become easier and more powerful. In this chapter, we describe how functional covariation arises during the evolution of proteins and how this signal can be distinguished from various background signals. We discuss the basic methodology for performing amino acid covariation analysis, using bacterial two-component signal transduction proteins as an example. We provide practical suggestions for each step of the process including assembly of protein sequences, construction of a multiple sequence alignment, measurement of covariation, and analysis of results. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. CXCL12 suppresses cisplatin-induced apoptosis through activation of JAK2/STAT3 signaling in human non-small-cell lung cancer cells

    Directory of Open Access Journals (Sweden)

    Wang M

    2017-06-01

    Full Text Available Meng Wang,1 Tie Lin,2 Yicun Wang,3 Song Gao,4 Zhaoyang Yang,1 Xuan Hong,1 Gongyan Chen1 1Department of Respiratory Medicine, Harbin Medical University Cancer Hospital, 2Department of Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, 3Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun, 4Department of Clinical Oncology, Shengjing Hospital, China Medical University, Shenyang, People’s Republic of China Aims: Poor efficacy of chemotherapy drugs in non-small-cell lung cancer (NSCLC is the key reason for the failure of treatment, but the mechanism of this remains largely unknown. Stromal cell-derived factor 1-alpha (SDF-1α/CXCL12 is a small chemotactic cytokine protein that plays an important role in tumor progression. In this study, we investigated the anti-apoptotic mechanism of the CXCL12/CXCR4 axis in response to cisplatin, a commonly used chemotherapeutic drug, in human lung adenocarcinoma A549 cells.Methods: CXCL12 blocks cisplatin-induced apoptosis in A549, and the results were shown by propidium iodide/annexin V staining in vitro. The mechanism of CXCL12 stimulating phosphorylation of STAT3 through CXCR4/JAK2 was demonstrated by immunofluorescence and Western blotting. The expression of CXCL12 and p-STAT3 in clinical specimens was examined by immunohistochemistry.Results: CXCL12 significantly decreased the ratio of apoptotic cells and stimulation of phospho-signal transducer and activator of transcription (p-STAT-3 in a time-dependent manner through interaction with CXCR4. Among the signaling molecules downstream of CXCR4, the JAK2/STAT3 pathway plays a predominant role in the anti-apoptotic effect of CXCL12. Analysis of clinical specimens revealed that increased CXCL12 and p-STAT3 expression correlates with enhanced lung cancer progression.Conclusion: These data suggest that CXCR4 contributes to CXCL12-mediated anti-apoptosis by activating JAK2

  16. Viscoplastic-dynamic analyses of small-scale fracture tests to obtain crack arrest toughness values for PTS conditions

    International Nuclear Information System (INIS)

    Kanninen, M.F.; Hudak, S.J. Jr; Dexter, R.J.; Couque, H.; O'Donoghue, P.E.; Polch, E.Z.

    1988-01-01

    Reliable predictions of crack arrest at the high upper shelf toughness conditions involved in postulated pressurized thermal shock (PTS) events require procedures beyond those utilized in conventional fracture mechanics treatments. To develop such a procedure, viscoplastic-dynamic fracture mechanics finite element analyses, viscoplastic material characterization testing, and small-scale crack propagation and arrest experimentation are being combines in this research. The approach couples SwRI's viscoplastic-dynamic fracture mechanics finite element code VISCRK with experiments using duplex 4340/A533B steel compact specimens. The experiments are simulated by VISCRK computations employing the Bodner-Partom viscoplastic constitutive relation and the nonlinear fracture mechanics parameter T. The goal is to develop temperature-dependent crack arrest toughness values for A533B steel. While only room temperature K Ia values have been obtained so far, these have been found to agree closely with those obtained from wide plate tests. (author)

  17. Analysing the Relevance of Experience Partitions to the Prediction of Players’ Self-Reports of Affect

    DEFF Research Database (Denmark)

    Martínez, Héctor Pérez; Yannakakis, Georgios N.

    2011-01-01

    A common practice in modeling affect from physiological signals consists of reducing the signals to a set of statistical features that feed predictors of self-reported emotions. This paper analyses the impact of various time-windows, used for the extraction of physiological features, to the accur......A common practice in modeling affect from physiological signals consists of reducing the signals to a set of statistical features that feed predictors of self-reported emotions. This paper analyses the impact of various time-windows, used for the extraction of physiological features...

  18. Detection of nonstationary transition to synchronized states of a neural network using recurrence analyses

    Science.gov (United States)

    Budzinski, R. C.; Boaretto, B. R. R.; Prado, T. L.; Lopes, S. R.

    2017-07-01

    We study the stability of asymptotic states displayed by a complex neural network. We focus on the loss of stability of a stationary state of networks using recurrence quantifiers as tools to diagnose local and global stabilities as well as the multistability of a coupled neural network. Numerical simulations of a neural network composed of 1024 neurons in a small-world connection scheme are performed using the model of Braun et al. [Int. J. Bifurcation Chaos 08, 881 (1998), 10.1142/S0218127498000681], which is a modified model from the Hodgkin-Huxley model [J. Phys. 117, 500 (1952)]. To validate the analyses, the results are compared with those produced by Kuramoto's order parameter [Chemical Oscillations, Waves, and Turbulence (Springer-Verlag, Berlin Heidelberg, 1984)]. We show that recurrence tools making use of just integrated signals provided by the networks, such as local field potential (LFP) (LFP signals) or mean field values bring new results on the understanding of neural behavior occurring before the synchronization states. In particular we show the occurrence of different stationary and nonstationarity asymptotic states.

  19. Ectopic expression of miR-34a enhances radiosensitivity of non-small cell lung cancer cells, partly by suppressing the LyGDI signaling pathway

    International Nuclear Information System (INIS)

    Duan Weiming; Xu Yaxiang; Dong Yujin; Cao Lili; Tong Jian; Zhou Xinwen

    2013-01-01

    miR-34a is transcriptionally induced by the tumor suppressor gene p53, which is often downregulated in non-small cell lung cancer (NSCLC). To address whether the downstream signal of miR-34a is sufficient to induce apoptosis and to alter cellular radiosensitivity, a chemical synthetic miR-34a mimic was delivered into A549 and H1299 cells, with or without co-treatment of γ-irradiation. Results showed that ectopic expression of miR-34a induced dose-dependent cell growth inhibition and apoptosis in a p53-independent manner in both NSCLC cell lines. Interestingly, LyGDI was discovered as a new target gene of miR-34a, and downregulation of LyGDI promoted Rac1 activation and membrane translocation, resulting in cell apoptosis. Furthermore, restoration of miR-34a indirectly reduced cyclooxygenase-2 (COX-2) expression. Taken together, these results demonstrate that restoration of miR-34a expression enhances radiation-induced apoptosis, partly by suppressing the LyGDI signaling pathway, and miR-34a could possibly be used as a radiosensitizer for non-small cell lung cancer therapy. (author)

  20. Intra-Tumour Signalling Entropy Determines Clinical Outcome in Breast and Lung Cancer

    Science.gov (United States)

    Banerji, Christopher R. S.; Severini, Simone; Caldas, Carlos; Teschendorff, Andrew E.

    2015-01-01

    The cancer stem cell hypothesis, that a small population of tumour cells are responsible for tumorigenesis and cancer progression, is becoming widely accepted and recent evidence has suggested a prognostic and predictive role for such cells. Intra-tumour heterogeneity, the diversity of the cancer cell population within the tumour of an individual patient, is related to cancer stem cells and is also considered a potential prognostic indicator in oncology. The measurement of cancer stem cell abundance and intra-tumour heterogeneity in a clinically relevant manner however, currently presents a challenge. Here we propose signalling entropy, a measure of signalling pathway promiscuity derived from a sample’s genome-wide gene expression profile, as an estimate of the stemness of a tumour sample. By considering over 500 mixtures of diverse cellular expression profiles, we reveal that signalling entropy also associates with intra-tumour heterogeneity. By analysing 3668 breast cancer and 1692 lung adenocarcinoma samples, we further demonstrate that signalling entropy correlates negatively with survival, outperforming leading clinical gene expression based prognostic tools. Signalling entropy is found to be a general prognostic measure, valid in different breast cancer clinical subgroups, as well as within stage I lung adenocarcinoma. We find that its prognostic power is driven by genes involved in cancer stem cells and treatment resistance. In summary, by approximating both stemness and intra-tumour heterogeneity, signalling entropy provides a powerful prognostic measure across different epithelial cancers. PMID:25793737

  1. Intra-tumour signalling entropy determines clinical outcome in breast and lung cancer.

    Directory of Open Access Journals (Sweden)

    Christopher R S Banerji

    2015-03-01

    Full Text Available The cancer stem cell hypothesis, that a small population of tumour cells are responsible for tumorigenesis and cancer progression, is becoming widely accepted and recent evidence has suggested a prognostic and predictive role for such cells. Intra-tumour heterogeneity, the diversity of the cancer cell population within the tumour of an individual patient, is related to cancer stem cells and is also considered a potential prognostic indicator in oncology. The measurement of cancer stem cell abundance and intra-tumour heterogeneity in a clinically relevant manner however, currently presents a challenge. Here we propose signalling entropy, a measure of signalling pathway promiscuity derived from a sample's genome-wide gene expression profile, as an estimate of the stemness of a tumour sample. By considering over 500 mixtures of diverse cellular expression profiles, we reveal that signalling entropy also associates with intra-tumour heterogeneity. By analysing 3668 breast cancer and 1692 lung adenocarcinoma samples, we further demonstrate that signalling entropy correlates negatively with survival, outperforming leading clinical gene expression based prognostic tools. Signalling entropy is found to be a general prognostic measure, valid in different breast cancer clinical subgroups, as well as within stage I lung adenocarcinoma. We find that its prognostic power is driven by genes involved in cancer stem cells and treatment resistance. In summary, by approximating both stemness and intra-tumour heterogeneity, signalling entropy provides a powerful prognostic measure across different epithelial cancers.

  2. Small-molecule synthetic compound norcantharidin reverses multi-drug resistance by regulating Sonic hedgehog signaling in human breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Yu-Jen Chen

    Full Text Available Multi-drug resistance (MDR, an unfavorable factor compromising treatment efficacy of anticancer drugs, involves upregulated ATP binding cassette (ABC transporters and activated Sonic hedgehog (Shh signaling. By preparing human breast cancer MCF-7 cells resistant to doxorubicin (DOX, we examined the effect and mechanism of norcantharidin (NCTD, a small-molecule synthetic compound, on reversing multidrug resistance. The DOX-prepared MCF-7R cells also possessed resistance to vinorelbine, characteristic of MDR. At suboptimal concentration, NCTD significantly inhibited the viability of DOX-sensitive (MCF-7S and DOX-resistant (MCF-7R cells and reversed the resistance to DOX and vinorelbine. NCTD increased the intracellular accumulation of DOX in MCF-7R cells and suppressed the upregulated the mdr-1 mRNA, P-gp and BCRP protein expression, but not the MRP-1. The role of P-gp was strengthened by partial reversal of the DOX and vinorelbine resistance by cyclosporine A. NCTD treatment suppressed the upregulation of Shh expression and nuclear translocation of Gli-1, a hallmark of Shh signaling activation in the resistant clone. Furthermore, the Shh ligand upregulated the expression of P-gp and attenuated the growth inhibitory effect of NCTD. The knockdown of mdr-1 mRNA had not altered the expression of Shh and Smoothened in both MCF-7S and MCF-7R cells. This indicates that the role of Shh signaling in MDR might be upstream to mdr-1/P-gp, and similar effect was shown in breast cancer MDA-MB-231 and BT-474 cells. This study demonstrated that NCTD may overcome multidrug resistance through inhibiting Shh signaling and expression of its downstream mdr-1/P-gp expression in human breast cancer cells.

  3. Chromogenic in situ hybridisation (CISH) is a powerful method to detect ALK-positive non-small cell lung carcinomas.

    Science.gov (United States)

    Wagner, F; Streubel, A; Roth, A; Stephan-Falkenau, S; Mairinger, T

    2014-05-01

    We assessed the potential of a chromogenic in situ hybridisation (CISH) assay in comparison with quantitative reverse transcription (RT)-PCR (qPCR) to detect anaplastic lymphoma kinase (ALK) break apart-positive lung carcinomas. Dual-colour CISH using a break apart probe for the ALK gene on 2p23 was performed with 181 formalin-fixed, paraffin-embedded tissue and agar block sections from 175 cases of non-small cell lung carcinomas (NSCLC). Stained slides were analysed with a standard bright-field microscope at 1000× magnification by counting signals from 60 non-overlapping nuclei from three different tumour areas. Samples with ≥15% of positive nuclei were judged as ALK break apart-positive. All samples were simultaneously analysed by qPCR for EML4-ALK to validate CISH results, and positive samples were subject to Sanger sequencing. CISH was successful with 173 of 181 hybridised samples (96%), and seven ALK break apart-positive cases were detected. CISH signals were specific and distinct for both colours. All positive cases were confirmed by qPCR and Sanger sequencing, and concordance between CISH and qPCR was 100%. Nearly all samples (9/10) which failed by qPCR were accessible to CISH analysis. CISH is a very reliable, convenient and inexpensive method to detect ALK-positive NSCLC. CISH success rate is comparably high as with qPCR, and it detects all ALK break apart events in a single assay. It is of special value when RNA quality is poor, or when small biopsies with a very limited amount of tumour cells have to be analysed.

  4. Meta-analyses on viral hepatitis

    DEFF Research Database (Denmark)

    Gluud, Lise L; Gluud, Christian

    2009-01-01

    This article summarizes the meta-analyses of interventions for viral hepatitis A, B, and C. Some of the interventions assessed are described in small trials with unclear bias control. Other interventions are supported by large, high-quality trials. Although attempts have been made to adjust...

  5. Suppression of Wnt signaling by the miR-29 family is mediated by demethylation of WIF-1 in non-small-cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Min [Department of Respiratory Medicine, Shanghai Tenth People’s Hospital, Tongji University, Shanghai 200072 (China); Wu, Junjie, E-mail: wujunjiesh@126.com [Department of Pneumology, Changhai Hospital of Shanghai, Second Military Medical University, Shanghai 200433 (China); State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai 200433 (China); Cai, Yong, E-mail: dryongcai@126.com [Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433 (China)

    2013-09-06

    Highlights: •Dnmt3A and Dnmt3B are involved in the down-regulation of WIF-1 expression in non-small-cell lung cancer. •MiR-29 family members could restore WIF-1 expression through demethylation. •MiR-29s suppress Wnt/β-catenin signaling pathway and inhibit tumor growth. •The expression of miR-29a and miR-29b could be regulated partially in a positive feedback loop. -- Abstract: Wnt inhibitory factor-1 (WIF-1) silencing induced by promoter hypermethylation is a common mechanism of aberrant activation of the Wnt signaling pathway in non-small-cell lung cancer (NSCLC). However, the activity of regulators associated with the methylation of the WIF-1 gene remains unclear. Here, we investigated the role of three DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) in the expression of WIF-1. The three DNMTs were up-regulated in NSCLC tumor tissues and suppression of DNMT3A and DNMT3B restored the expression of WIF-1 in NSCLC cells. The miR-29 family (miR-29a, -29b, and -29c), which negatively regulates DNMT3A and DNMT3B, was examined in association with the Wnt/β-catenin signaling pathway. A positive correlation between the expression of WIF-1 and that of MiR-29s was observed in NSCLC tissues. Methylation-specific PCR and Western blotting indicated that miR-29s positively regulate WIF-1 expression by inhibiting the methylation of its promoter. Furthermore, miR-29 overexpression downregulated β-catenin expression, inhibited cell proliferation and induced apoptosis. The expression of miR-29a and miR-29b was partially regulated by DNMT3A and DNMT3B in a positive feedback loop. Taken together, our findings show that miR-29s suppress the Wnt signaling pathway through demethylation of WIF-1 in NSCLC.

  6. Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sangwon [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    Matrix-assisted laser desorption/ionization(MALDI) mass spectrometry(MS) has been widely used for analysis of biological molecules, especially macromolecules such as proteins. However, MALDI MS has a problem in small molecule (less than 1 kDa) analysis because of the signal saturation by organic matrixes in the low mass region. In imaging MS (IMS), inhomogeneous surface formation due to the co-crystallization process by organic MALDI matrixes limits the spatial resolution of the mass spectral image. Therefore, to make laser desorption/ionization (LDI) MS more suitable for mass spectral profiling and imaging of small molecules directly from raw biological tissues, LDI MS protocols with various alternative assisting materials were developed and applied to many biological systems of interest. Colloidal graphite was used as a matrix for IMS of small molecules for the first time and methodologies for analyses of small metabolites in rat brain tissues, fruits, and plant tissues were developed. With rat brain tissues, the signal enhancement for cerebroside species by colloidal graphite was observed and images of cerebrosides were successfully generated by IMS. In addition, separation of isobaric lipid ions was performed by imaging tandem MS. Directly from Arabidopsis flowers, flavonoids were successfully profiled and heterogeneous distribution of flavonoids in petals was observed for the first time by graphite-assisted LDI(GALDI) IMS.

  7. CW gain measurements in small-bore argon-ion laser discharges using a novel modulation technique

    International Nuclear Information System (INIS)

    Bennett, W.R. Jr.; Sze, R.C.

    1974-01-01

    A technique for small-signal gain measurements for cw laser systems is described. The method is applied to the measurement of multimode small-signal gain coefficients of small-bone argon-ion laser transitions. (U.S.)

  8. Unconstrained and Noninvasive Measurement of Swimming Behavior of Small Fish Based on Ventilatory Signals

    Science.gov (United States)

    Kitayama, Shigehisa; Soh, Zu; Hirano, Akira; Tsuji, Toshio; Takiguchi, Noboru; Ohtake, Hisao

    Ventilatory signal is a kind of bioelectric signals reflecting the ventilatory conditions of fish, and has received recent attention as an indicator for assessment of water quality, since breathing is adjusted by the respiratory center according to changes in the underwater environment surrounding the fish. The signals are thus beginning to be used in bioassay systems for water examination. Other than ventilatory conditions, swimming behavior also contains important information for water examination. The conventional bioassay systems, however, only measure either ventilatory signals or swimming behavior. This paper proposes a new unconstrained and noninvasive measurement method that is capable of conducting ventilatory signal measurement and behavioral analysis of fish at the same time. The proposed method estimates the position and the velocity of a fish in free-swimming conditions using power spectrum distribution of measured ventilatory signals from multiple electrodes. This allowed the system to avoid using a camera system which requires light sources. In order to validate estimation accuracy, the position and the velocity estimated by the proposed method were compared to those obtained from video analysis. The results confirmed that the estimated error of the fish positions was within the size of fish, and the correlation coefficient between the velocities was 0.906. The proposed method thus not only can measure the ventilatory signals, but also performs behavioral analysis as accurate as using a video camera.

  9. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  10. A Digital Signal Processor for Doppler Radar Sensing of Vital Signs

    Science.gov (United States)

    2001-10-25

    shows a small spike halfway each heartbeat. This is known as the dicrotic notch , which signifies a sudden drop in pressure after systolic contraction...It is caused by a small reflux flow of blood back into the aortic valve and coronary vessels. This dicrotic notch in the heart signal is clipped...signal, and amax was the maximum amplitude of the signal in the specified window. The user could set the factor k, and it determined the threshold at

  11. The impact of database restriction on pharmacovigilance signal detection of selected cancer therapies.

    Science.gov (United States)

    Hauben, Manfred; Hung, Eric; Wood, Jennifer; Soitkar, Amit; Reshef, Daniel

    2017-05-01

    The aim of this study was to investigate whether database restriction can improve oncology drug pharmacovigilance signal detection performance. We used spontaneous adverse event (AE) reports in the United States (US) Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database. Positive control (PC) drug medical concept (DMC) pairs were selected from safety information not included in the product's first label but subsequently added as label changes. These medical concepts (MCs) were mapped to the Medical Dictionary for Regulatory Activities (MedDRA) preferred terms (PTs) used in FAERS to code AEs. Negative controls (NC) were MCs with circumscribed PTs not included in the corresponding US package insert (USPI). We calculated shrinkage-adjusted observed-to-expected (O/E) reporting frequencies for the aforementioned drug-PT pairs. We also formulated an adjudication framework to calculate performance at the MC level. Performance metrics [sensitivity, specificity, positive and negative predictive value (PPV, NPV), signal/noise (S/N), F and Matthews correlation coefficient (MCC)] were calculated for each analysis and compared. The PC reference set consisted of 11 drugs, 487 PTs, 27 MCs, 37 drug-MC combinations and 638 drug-event combinations (DECs). The NC reference set consisted of 11 drugs, 9 PTs, 5 MCs, 40 drug-MC combinations and 67 DECs. Most drug-event pairs were not highlighted by either analysis. A small percentage of signals of disproportionate reporting were lost, more noise than signal, with no gains. Specificity and PPV improved whereas sensitivity, NPV, F and MCC decreased, but all changes were small relative to the decrease in sensitivity. The overall S/N improved. This oncology drug restricted analysis improved the S/N ratio, removing proportionately more noise than signal, but with significant credible signal loss. Without broader experience and a calculus of costs and utilities of correct versus incorrect classifications in

  12. Analysis of acoustic emission signals of fatigue crack growth and corrosion processes. Investigation of the possibilities for continuous condition monitoring of transport containers by acoustic emission testing; Analyse der Schallemissionssignale aus Ermuedungsrisswachstum und Korrosionsprozessen. Untersuchung der Moeglichkeiten fuer die kontinuierliche Zustandsueberwachung von Transportbehaeltern mittels Schallemissionspruefung

    Energy Technology Data Exchange (ETDEWEB)

    Wachsmuth, Janne

    2016-05-01

    generated application oriented, on plates within the heat affected zone of a weld. Their AE signals were recorded with resonant sensors. On the one hand resonant sensors are very sensitive and able to detect small displacements on huge structures, which makes them applicable for condition monitoring. On the other hand, resonant sensors have a great influence on the AE signals and hinder signal analyses and pattern recognition. Pure fatigue crack growth, fatigue crack growth in a corrosive environment and pure corrosion were applied. Signal groups of the damage mechanisms were compared by their AE features. Differences between signal groups could be made after wave mode analysis, despite the spectral influence of the AE sensors. The damage condition of the test plates is investigated with the combination of AE features of the signal groups and fracture mechanic parameters. Furthermore, two methods of unsupervised pattern recognition of the AE signals are being performed: A commercial classification system, where mainly frequency based features are generated, and an AE feature based method. In the latter, classification takes place after the frequency distributions of the AE features of the signals from the examined damage mechanisms. Both methods result in an accurate classification for the AE signals, especially originating from corrosion damage mechanisms, in the correct damage class. Concluding, the detectability of AE events, the results of pattern recognition of AE signals in metal structures and the prospects and risks of condition monitoring by means of acoustic emission testing are discussed. Therefore, monitoring tests on a tank car and results from cyclic and static loading are consulted. An assessment for the selection of the monitoring method according to the cost effectiveness of dangerous goods transportation is made.

  13. Selective killing of cancer cells by leaf extract of Ashwagandha: components, activity and pathway analyses.

    Science.gov (United States)

    Widodo, Nashi; Takagi, Yasuomi; Shrestha, Bhupal G; Ishii, Tetsuro; Kaul, Sunil C; Wadhwa, Renu

    2008-04-08

    Ashwagandha, also called as "Queen of Ayurveda" and "Indian ginseng", is a commonly used plant in Indian traditional medicine, Ayurveda. Its roots have been used as herb remedy to treat a variety of ailments and to promote general wellness. However, scientific evidence to its effects is limited to only a small number of studies. We had previously identified anti-cancer activity in the leaf extract (i-Extract) of Ashwagandha and demonstrated withanone as a cancer inhibitory factor (i-Factor). In the present study, we fractionated the i-Extract to its components by silica gel column chromatography and subjected them to cell based activity analyses. We found that the cancer inhibitory leaf extract (i-Extract) has, at least, seven components that could cause cancer cell killing; i-Factor showed the highest selectivity for cancer cells and i-Factor rich Ashwagandha leaf powder was non-toxic and anti-tumorigenic in mice assays. We undertook a gene silencing and pathway analysis approach and found that i-Extract and its components kill cancer cells by at least five different pathways, viz. p53 signaling, GM-CFS signaling, death receptor signaling, apoptosis signaling and G2-M DNA damage regulation pathway. p53 signaling was most common. Visual analysis of p53 and mortalin staining pattern further revealed that i-Extract, fraction F1, fraction F4 and i-Factor caused an abrogation of mortalin-p53 interactions and reactivation of p53 function while the fractions F2, F3, F5 work through other mechanisms.

  14. Het gentech debat ontleed : een analyse van terugkerende kernthema's en argumenten.

    NARCIS (Netherlands)

    Keulartz, F.W.J.; Oever, v.d. L.; Vriend, H.

    2007-01-01

    In deze signalering is een analyse gemaakt van het maatschappelijke debat rond genetische modificatie en haar toepassingen. Met deze analyse van het debat hoopt de COGEM overheden en andere betrokkenen meer inzicht in de terugkerende thema's en de gehanteerde argumenten te geven en de achtergronden

  15. EEG analyses with SOBI.

    Energy Technology Data Exchange (ETDEWEB)

    Glickman, Matthew R.; Tang, Akaysha (University of New Mexico, Albuquerque, NM)

    2009-02-01

    The motivating vision behind Sandia's MENTOR/PAL LDRD project has been that of systems which use real-time psychophysiological data to support and enhance human performance, both individually and of groups. Relevant and significant psychophysiological data being a necessary prerequisite to such systems, this LDRD has focused on identifying and refining such signals. The project has focused in particular on EEG (electroencephalogram) data as a promising candidate signal because it (potentially) provides a broad window on brain activity with relatively low cost and logistical constraints. We report here on two analyses performed on EEG data collected in this project using the SOBI (Second Order Blind Identification) algorithm to identify two independent sources of brain activity: one in the frontal lobe and one in the occipital. The first study looks at directional influences between the two components, while the second study looks at inferring gender based upon the frontal component.

  16. Non-Smad signaling pathways.

    Science.gov (United States)

    Mu, Yabing; Gudey, Shyam Kumar; Landström, Maréne

    2012-01-01

    Transforming growth factor-beta (TGFβ) is a key regulator of cell fate during embryogenesis and has also emerged as a potent driver of the epithelial-mesenchymal transition during tumor progression. TGFβ signals are transduced by transmembrane type I and type II serine/threonine kinase receptors (TβRI and TβRII, respectively). The activated TβR complex phosphorylates Smad2 and Smad3, converting them into transcriptional regulators that complex with Smad4. TGFβ also uses non-Smad signaling pathways such as the p38 and Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways to convey its signals. Ubiquitin ligase tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6) and TGFβ-associated kinase 1 (TAK1) have recently been shown to be crucial for the activation of the p38 and JNK MAPK pathways. Other TGFβ-induced non-Smad signaling pathways include the phosphoinositide 3-kinase-Akt-mTOR pathway, the small GTPases Rho, Rac, and Cdc42, and the Ras-Erk-MAPK pathway. Signals induced by TGFβ are tightly regulated and specified by post-translational modifications of the signaling components, since they dictate the subcellular localization, activity, and duration of the signal. In this review, we discuss recent findings in the field of TGFβ-induced responses by non-Smad signaling pathways.

  17. Analysing malaria incidence at the small area level for developing a spatial decision support system: A case study in Kalaburagi, Karnataka, India.

    Science.gov (United States)

    Shekhar, S; Yoo, E-H; Ahmed, S A; Haining, R; Kadannolly, S

    2017-02-01

    Spatial decision support systems have already proved their value in helping to reduce infectious diseases but to be effective they need to be designed to reflect local circumstances and local data availability. We report the first stage of a project to develop a spatial decision support system for infectious diseases for Karnataka State in India. The focus of this paper is on malaria incidence and we draw on small area data on new cases of malaria analysed in two-monthly time intervals over the period February 2012 to January 2016 for Kalaburagi taluk, a small area in Karnataka. We report the results of data mapping and cluster detection (identifying areas of excess risk) including evaluating the temporal persistence of excess risk and the local conditions with which high counts are statistically associated. We comment on how this work might feed into a practical spatial decision support system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Signal and image processing in medical applications

    CERN Document Server

    Kumar, Amit; Rahim, B Abdul; Kumar, D Sravan

    2016-01-01

    This book highlights recent findings on and analyses conducted on signals and images in the area of medicine. The experimental investigations involve a variety of signals and images and their methodologies range from very basic to sophisticated methods. The book explains how signal and image processing methods can be used to detect and forecast abnormalities in an easy-to-follow manner, offering a valuable resource for researchers, engineers, physicians and bioinformatics researchers alike.

  19. Validation of morphometric analyses of small-intestinal biopsy readouts in celiac disease.

    Directory of Open Access Journals (Sweden)

    Juha Taavela

    Full Text Available BACKGROUND: Assessment of the gluten-induced small-intestinal mucosal injury remains the cornerstone of celiac disease diagnosis. Usually the injury is evaluated using grouped classifications (e.g. Marsh groups, but this is often too imprecise and ignores minor but significant changes in the mucosa. Consequently, there is a need for validated continuous variables in everyday practice and in academic and pharmacological research. METHODS: We studied the performance of our standard operating procedure (SOP on 93 selected biopsy specimens from adult celiac disease patients and non-celiac disease controls. The specimens, which comprised different grades of gluten-induced mucosal injury, were evaluated by morphometric measurements. Specimens with tangential cutting resulting from poorly oriented biopsies were included. Two accredited evaluators performed the measurements in blinded fashion. The intraobserver and interobserver variations for villus height and crypt depth ratio (VH:CrD and densities of intraepithelial lymphocytes (IELs were analyzed by the Bland-Altman method and intraclass correlation. RESULTS: Unevaluable biopsies according to our SOP were correctly identified. The intraobserver analysis of VH:CrD showed a mean difference of 0.087 with limits of agreement from -0.398 to 0.224; the standard deviation (SD was 0.159. The mean difference in interobserver analysis was 0.070, limits of agreement -0.516 to 0.375, and SD 0.227. The intraclass correlation coefficient in intraobserver variation was 0.983 and that in interobserver variation 0.978. CD3(+ IEL density countings in the paraffin-embedded and frozen biopsies showed SDs of 17.1% and 16.5%; the intraclass correlation coefficients were 0.961 and 0.956, respectively. CONCLUSIONS: Using our SOP, quantitative, reliable and reproducible morphometric results can be obtained on duodenal biopsy specimens with different grades of gluten-induced injury. Clinically significant changes were

  20. Metagenome-based diversity analyses suggest a strong locality signal for bacterial communities associated with oyster aquaculture farms in Ofunato Bay

    KAUST Repository

    Kobiyama, Atsushi

    2018-04-30

    Ofunato Bay, in Japan, is the home of buoy-and-rope-type oyster aquaculture activities. Since the oysters filter suspended materials and excrete organic matter into the seawater, bacterial communities residing in its vicinity may show dynamic changes depending on the oyster culture activities. We employed a shotgun metagenomic technique to study bacterial communities near oyster aquaculture facilities at the center of the bay (KSt. 2) and compared the results with those of two other localities far from the station, one to the northeast (innermost bay, KSt. 1) and the other to the southwest (bay entrance, KSt. 3). Seawater samples were collected every month from January to December 2015 from the surface (1 m) and deeper (8 or 10 m) layers of the three locations, and the sequentially filtered fraction on 0.2-μm membranes was sequenced on an Illumina MiSeq system. The acquired reads were uploaded to MG-RAST for KEGG functional abundance analysis, while taxonomic analyses at the phylum and genus levels were performed using MEGAN after parsing the BLAST output. Discrimination analyses were then performed using the ROC-AUC value of the cross validation, targeting the depth (shallow or deep), locality [(KSt. 1 + KSt. 2) vs. KSt 3; (KSt. 1 + KSt. 3) vs. KSt. 2 or the (KSt. 2 + KSt. 3) vs. KSt. 1] and seasonality (12 months). The matrix discrimination analysis on the adjacent 2 continuous seasons by ROC-AUC, which was based on the datasets that originated from different depths, localities and months, showed the strongest discrimination signal on the taxonomy matrix at the phylum level for the datasets from July to August compared with those from September to June, while the KEGG matrix showed the strongest signal for the datasets from March to June compared with those from July to February. Then, the locality combination was subjected to the same ROC-AUC discrimination analysis, resulting in significant differences between KSt. 2 and KSt. 1 + KSt. 3

  1. Metagenome-based diversity analyses suggest a strong locality signal for bacterial communities associated with oyster aquaculture farms in Ofunato Bay

    KAUST Repository

    Kobiyama, Atsushi; Ikeo, Kazuho; Reza, Md. Shaheed; Rashid, Jonaira; Yamada, Yuichiro; Ikeda, Yuri; Ikeda, Daisuke; Mizusawa, Nanami; Sato, Shigeru; Ogata, Takehiko; Jimbo, Mitsuru; Kudo, Toshiaki; Kaga, Shinnosuke; Watanabe, Shiho; Naiki, Kimiaki; Kaga, Yoshimasa; Mineta, Katsuhiko; Bajic, Vladimir B.; Gojobori, Takashi; Watabe, Shugo

    2018-01-01

    Ofunato Bay, in Japan, is the home of buoy-and-rope-type oyster aquaculture activities. Since the oysters filter suspended materials and excrete organic matter into the seawater, bacterial communities residing in its vicinity may show dynamic changes depending on the oyster culture activities. We employed a shotgun metagenomic technique to study bacterial communities near oyster aquaculture facilities at the center of the bay (KSt. 2) and compared the results with those of two other localities far from the station, one to the northeast (innermost bay, KSt. 1) and the other to the southwest (bay entrance, KSt. 3). Seawater samples were collected every month from January to December 2015 from the surface (1 m) and deeper (8 or 10 m) layers of the three locations, and the sequentially filtered fraction on 0.2-μm membranes was sequenced on an Illumina MiSeq system. The acquired reads were uploaded to MG-RAST for KEGG functional abundance analysis, while taxonomic analyses at the phylum and genus levels were performed using MEGAN after parsing the BLAST output. Discrimination analyses were then performed using the ROC-AUC value of the cross validation, targeting the depth (shallow or deep), locality [(KSt. 1 + KSt. 2) vs. KSt 3; (KSt. 1 + KSt. 3) vs. KSt. 2 or the (KSt. 2 + KSt. 3) vs. KSt. 1] and seasonality (12 months). The matrix discrimination analysis on the adjacent 2 continuous seasons by ROC-AUC, which was based on the datasets that originated from different depths, localities and months, showed the strongest discrimination signal on the taxonomy matrix at the phylum level for the datasets from July to August compared with those from September to June, while the KEGG matrix showed the strongest signal for the datasets from March to June compared with those from July to February. Then, the locality combination was subjected to the same ROC-AUC discrimination analysis, resulting in significant differences between KSt. 2 and KSt. 1 + KSt. 3

  2. Design, Construction, and Use of a Single Board Computer Beowulf Cluster: Application of the Small-Footprint, Low-Cost, InSignal 5420 Octa Board

    OpenAIRE

    Cusick, James J.; Miller, William; Laurita, Nicholas; Pitt, Tasha

    2014-01-01

    In recent years development in the area of Single Board Computing has been advancing rapidly. At Wolters Kluwer's Corporate Legal Services Division a prototyping effort was undertaken to establish the utility of such devices for practical and general computing needs. This paper presents the background of this work, the design and construction of a 64 core 96 GHz cluster, and their possibility of yielding approximately 400 GFLOPs from a set of small footprint InSignal boards created for just o...

  3. Signal classification for acoustic neutrino detection

    International Nuclear Information System (INIS)

    Neff, M.; Anton, G.; Enzenhöfer, A.; Graf, K.; Hößl, J.; Katz, U.; Lahmann, R.; Richardt, C.

    2012-01-01

    This article focuses on signal classification for deep-sea acoustic neutrino detection. In the deep sea, the background of transient signals is very diverse. Approaches like matched filtering are not sufficient to distinguish between neutrino-like signals and other transient signals with similar signature, which are forming the acoustic background for neutrino detection in the deep-sea environment. A classification system based on machine learning algorithms is analysed with the goal to find a robust and effective way to perform this task. For a well-trained model, a testing error on the level of 1% is achieved for strong classifiers like Random Forest and Boosting Trees using the extracted features of the signal as input and utilising dense clusters of sensors instead of single sensors.

  4. Preliminary Analyses of Beidou Signal-In Anomaly Since 2013

    Science.gov (United States)

    Wu, Y.; Ren, J.; Liu, W.

    2016-06-01

    As BeiDou navigation system has been operational since December 2012. There is an increasing desire to use multiple constellation to improve positioning performance. The signal-in-space (SIS) anomaly caused by the ground control and the space vehicle is one of the major threats to affect the integrity. For a young Global Navigation Satellite System, knowledge about SIS anomalies in history is very important for not only assessing the SIS integrity performance of a constellation but also providing the assumption for ARAIM (Advanced Receiver Autonomous Integrity Monitoring). In this paper, the broadcast ephemerides and the precise ones are pre-processed for avoiding the false anomaly identification. The SIS errors over the period of Mar. 2013-Feb. 2016 are computed by comparing the broadcast ephemerides with the precise ones. The time offsets between GPST (GPS time) and BDT (BeiDou time) are estimated and removed by an improved estimation algorithm. SIS worst-UREs are computed and a RMS criteria are investigated to identify the SIS anomalies. The results show that the probability of BeiDou SIS anomalies is in 10-3 level in last three years. Even though BeiDou SIS integrity performance currently cannot match the GPS integrity performances, the result indicates that BeiDou has a tendency to improve its integrity performance.

  5. Cross Time-Frequency Analysis of Gastrocnemius Electromyographic Signals in Hypertensive and Nonhypertensive Subjects

    Science.gov (United States)

    Mitchell, Patrick; Krotish, Debra; Shin, Yong-June; Hirth, Victor

    2010-12-01

    The effects of hypertension are chronic and continuous; it affects gait, balance, and fall risk. Therefore, it is desirable to assess gait health across hypertensive and nonhypertensive subjects in order to prevent or reduce the risk of falls. Analysis of electromyography (EMG) signals can identify age related changes of neuromuscular activation due to various neuropathies and myopathies, but it is difficult to translate these medical changes to clinical diagnosis. To examine and compare geriatrics patients with these gait-altering diseases, we acquire EMG muscle activation signals, and by use of a timesynchronized mat capable of recording pressure information, we localize the EMG data to the gait cycle, ensuring identical comparison across subjects. Using time-frequency analysis on the EMG signal, in conjunction with several parameters obtained from the time-frequency analyses, we can determine the statistical discrepancy between diseases. We base these parameters on physiological manifestations caused by hypertension, as well as other comorbities that affect the geriatrics community. Using these metrics in a small population, we identify a statistical discrepancy between a control group and subjects with hypertension, neuropathy, diabetes, osteoporosis, arthritis, and several other common diseases which severely affect the geriatrics community.

  6. Small G proteins in insulin action: Rab and Rho families at the crossroads of signal transduction and GLUT4 vesicle traffic.

    Science.gov (United States)

    Ishikura, S; Koshkina, A; Klip, A

    2008-01-01

    Insulin stimulates glucose uptake into muscle and adipose tissues through glucose transporter 4 (GLUT4). GLUT4 cycles between the intracellular compartments and the plasma membrane. GLUT4 traffic-regulating insulin signals are largely within the insulin receptor-insulin receptor substrate-phosphatidylinositol 3-kinase (IR-IRS-PI3K) axis. In muscle cells, insulin signal bifurcates downstream of the PI3K into one arm leading to the activation of the Ser/Thr kinases Akt and atypical protein kinase C, and another leading to the activation of Rho family protein Rac1 leading to actin remodelling. Activated Akt inactivates AS160, a GTPase-activating protein for Rab family small G proteins. Here we review the roles of Rab and Rho proteins, particularly Rab substrates of AS160 and Rac1, in insulin-stimulated GLUT4 traffic. We discuss: (1) how distinct steps in GLUT4 traffic may be regulated by discrete Rab proteins, and (2) the importance of Rac1 activation in insulin-induced actin remodelling in muscle cells, a key element for the net gain in surface GLUT4.

  7. Digital signal processing applied to crystal identification in Positron Emission Tomography dedicated to small animals

    International Nuclear Information System (INIS)

    Fontaine, Rejean; Viscogliosi, Nicolas; Semmaoui, Hicham; Belanger, Francois; Lemieux, Francois; Tetrault, Marc-Andre; Michaud, Jean-Baptiste; Berard, Philippe; Cadorette, Jules; Pepin, Catherine M.; Lecomte, Roger

    2007-01-01

    The recent introduction of all-digital electronic architecture in Positron Emission Tomography (PET) scanners, enables new paradigms to be explored for extracting relevant information from the detector signals, such as energy, time and crystal identification. The LabPET TM small animal scanner, which implements free-running 45-MHz sampling directly at the output of the charge sensitive preamplifiers, provides an excellent platform to test such advanced digital algorithms. A real-time identification method, based on an Auto-Regressive Moving-Average (ARMA) scheme, was tested for discriminating between LYSO (t r ∼40 ns) and LGSO (t r ∼65 ns) scintillators in phoswich detectors, coupled to a single Avalanche Photodiode (APD). Even with a low energy threshold of 250 keV applied individually, error rates 10%, typically with conventional analog pulse shape discrimination techniques. Such digital crystal identification techniques can be readily implemented with phoswich detectors for improving spatial resolution in PET, either by increasing crystal pixellization or by mitigating parallax errors through depth-of-interaction determination. It also allows to reduce the event rate presented to the real-time coincidence engine by applying a low energy limit at the crystal granularity and rejecting more Compton photons

  8. A soft-core processor architecture optimised for radar signal processing applications

    CSIR Research Space (South Africa)

    Broich, R

    2013-12-01

    Full Text Available -performance soft-core processing architecture is proposed. To develop such a processing architecture, data and signal-flow characteristics of common radar signal processing algorithms are analysed. Each algorithm is broken down into signal processing...

  9. Seismic signals hard clipping overcoming

    Science.gov (United States)

    Olszowa, Paula; Sokolowski, Jakub

    2018-01-01

    In signal processing the clipping is understand as the phenomenon of limiting the signal beyond certain threshold. It is often related to overloading of a sensor. Two particular types of clipping are being recognized: soft and hard. Beyond the limiting value soft clipping reduces the signal real gain while the hard clipping stiffly sets the signal values at the limit. In both cases certain amount of signal information is lost. Obviously if one possess the model which describes the considered signal and the threshold value (which might be slightly more difficult to obtain in the soft clipping case), the attempt of restoring the signal can be made. Commonly it is assumed that the seismic signals take form of an impulse response of some specific system. This may lead to belief that the sine wave may be the most appropriate to fit in the clipping period. However, this should be tested. In this paper the possibility of overcoming the hard clipping in seismic signals originating from a geoseismic station belonging to an underground mine is considered. A set of raw signals will be hard-clipped manually and then couple different functions will be fitted and compared in terms of least squares. The results will be then analysed.

  10. Passive safety injection experiments and analyses (PAHKO)

    International Nuclear Information System (INIS)

    Tuunanen, J.

    1998-01-01

    PAHKO project involved experiments on the PACTEL facility and computer simulations of selected experiments. The experiments focused on the performance of Passive Safety Injection Systems (PSIS) of Advanced Light Water Reactors (ALWRs) in Small Break Loss-Of-Coolant Accident (SBLOCA) conditions. The PSIS consisted of a Core Make-up Tank (CMT) and two pipelines (Pressure Balancing Line, PBL, and Injection Line, IL). The examined PSIS worked efficiently in SBLOCAs although the flow through the PSIS stopped temporarily if the break was very small and the hot water filled the CMT. The experiments demonstrated the importance of the flow distributor in the CMT to limit rapid condensation. The project included validation of three thermal-hydraulic computer codes (APROS, CATHARE and RELAP5). The analyses showed the codes are capable to simulate the overall behaviour of the transients. The detailed analyses of the results showed some models in the codes still need improvements. Especially, further development of models for thermal stratification, condensation and natural circulation flow with small driving forces would be necessary for accurate simulation of the PSIS phenomena. (orig.)

  11. Structural and magnetic properties of multi-core nanoparticles analysed using a generalised numerical inversion method

    Science.gov (United States)

    Bender, P.; Bogart, L. K.; Posth, O.; Szczerba, W.; Rogers, S. E.; Castro, A.; Nilsson, L.; Zeng, L. J.; Sugunan, A.; Sommertune, J.; Fornara, A.; González-Alonso, D.; Barquín, L. Fernández; Johansson, C.

    2017-01-01

    The structural and magnetic properties of magnetic multi-core particles were determined by numerical inversion of small angle scattering and isothermal magnetisation data. The investigated particles consist of iron oxide nanoparticle cores (9 nm) embedded in poly(styrene) spheres (160 nm). A thorough physical characterisation of the particles included transmission electron microscopy, X-ray diffraction and asymmetrical flow field-flow fractionation. Their structure was ultimately disclosed by an indirect Fourier transform of static light scattering, small angle X-ray scattering and small angle neutron scattering data of the colloidal dispersion. The extracted pair distance distribution functions clearly indicated that the cores were mostly accumulated in the outer surface layers of the poly(styrene) spheres. To investigate the magnetic properties, the isothermal magnetisation curves of the multi-core particles (immobilised and dispersed in water) were analysed. The study stands out by applying the same numerical approach to extract the apparent moment distributions of the particles as for the indirect Fourier transform. It could be shown that the main peak of the apparent moment distributions correlated to the expected intrinsic moment distribution of the cores. Additional peaks were observed which signaled deviations of the isothermal magnetisation behavior from the non-interacting case, indicating weak dipolar interactions. PMID:28397851

  12. Topological and functional properties of the small GTPases protein interaction network.

    Directory of Open Access Journals (Sweden)

    Anna Delprato

    Full Text Available Small GTP binding proteins of the Ras superfamily (Ras, Rho, Rab, Arf, and Ran regulate key cellular processes such as signal transduction, cell proliferation, cell motility, and vesicle transport. A great deal of experimental evidence supports the existence of signaling cascades and feedback loops within and among the small GTPase subfamilies suggesting that these proteins function in a coordinated and cooperative manner. The interplay occurs largely through association with bi-partite regulatory and effector proteins but can also occur through the active form of the small GTPases themselves. In order to understand the connectivity of the small GTPases signaling routes, a systems-level approach that analyzes data describing direct and indirect interactions was used to construct the small GTPases protein interaction network. The data were curated from the Search Tool for the Retrieval of Interacting Genes (STRING database and include only experimentally validated interactions. The network method enables the conceptualization of the overall structure as well as the underlying organization of the protein-protein interactions. The interaction network described here is comprised of 778 nodes and 1943 edges and has a scale-free topology. Rac1, Cdc42, RhoA, and HRas are identified as the hubs. Ten sub-network motifs are also identified in this study with themes in apoptosis, cell growth/proliferation, vesicle traffic, cell adhesion/junction dynamics, the nicotinamide adenine dinucleotide phosphate (NADPH oxidase response, transcription regulation, receptor-mediated endocytosis, gene silencing, and growth factor signaling. Bottleneck proteins that bridge signaling paths and proteins that overlap in multiple small GTPase networks are described along with the functional annotation of all proteins in the network.

  13. Anti-jamming Technology in Small Satellite Communication

    Science.gov (United States)

    Jia, Zixiang

    2018-01-01

    Small satellite communication has an increasingly important position among the wireless communications due to the advantages of low cost and high technology. However, in view of the case that its relay station stays outside the earth, its uplink may face interference from malicious signal frequently. Here this paper classified enumerates existing interferences, and proposes channel signals as main interference by comparison. Based on a basic digital communication process, then this paper discusses the possible anti - jamming techniques that commonly be realized at all stages in diverse processes, and comes to the conclusion that regarding the spread spectrum technology and antenna anti-jamming technology as fundamental direction of future development. This work provides possible thought for the design of new small satellite communication system with the coexistence of multi - technologies. This basic popular science can be consulted for people interested in small satellite communication.

  14. Adenylate Kinase and AMP Signaling Networks: Metabolic Monitoring, Signal Communication and Body Energy Sensing

    Directory of Open Access Journals (Sweden)

    Andre Terzic

    2009-04-01

    Full Text Available Adenylate kinase and downstream AMP signaling is an integrated metabolic monitoring system which reads the cellular energy state in order to tune and report signals to metabolic sensors. A network of adenylate kinase isoforms (AK1-AK7 are distributed throughout intracellular compartments, interstitial space and body fluids to regulate energetic and metabolic signaling circuits, securing efficient cell energy economy, signal communication and stress response. The dynamics of adenylate kinase-catalyzed phosphotransfer regulates multiple intracellular and extracellular energy-dependent and nucleotide signaling processes, including excitation-contraction coupling, hormone secretion, cell and ciliary motility, nuclear transport, energetics of cell cycle, DNA synthesis and repair, and developmental programming. Metabolomic analyses indicate that cellular, interstitial and blood AMP levels are potential metabolic signals associated with vital functions including body energy sensing, sleep, hibernation and food intake. Either low or excess AMP signaling has been linked to human disease such as diabetes, obesity and hypertrophic cardiomyopathy. Recent studies indicate that derangements in adenylate kinase-mediated energetic signaling due to mutations in AK1, AK2 or AK7 isoforms are associated with hemolytic anemia, reticular dysgenesis and ciliary dyskinesia. Moreover, hormonal, food and antidiabetic drug actions are frequently coupled to alterations of cellular AMP levels and associated signaling. Thus, by monitoring energy state and generating and distributing AMP metabolic signals adenylate kinase represents a unique hub within the cellular homeostatic network.

  15. Signal amplification and Pierce's instability in convergent particle beams

    International Nuclear Information System (INIS)

    Gnavi, G.; Gratton, F.T.

    1988-01-01

    Relativistic electron beams flowing between cylindrical and spherical electrodes (or solid angles sections of electrodes with these geometries) are studied. The beams are focused through the axis in the cylindrical case or through the center when spherical electrodes are considered. It is assumed that the external electrode is part of a device which accelerates the particles, the inner electrode is passive and removes the beams from the system. Electrons move by inertia in the interelectrode space, neutralized by an ion background. Properties of radial, small amplitude, perturbations are analyzed theoretically. Previous analyses of counterstreaming beams indicated that convergence modifies considerably the oscillations spectrum. Here, results on the amplification of signals when a beam is modulated at the external electrode are reported. Then, conditions for the instability of a beam when it flows through grounded electrodes (Pierce's instability of only one beam) are examined

  16. Small-Signal Analysis of Autonomous Hybrid Distributed Generation Systems in Presence of Ultracapacitor and Tie-Line Operation

    Science.gov (United States)

    Ray, Prakash K.; Mohanty, Soumya R.; Kishor, Nand

    2010-07-01

    This paper presents small-signal analysis of isolated as well as interconnected autonomous hybrid distributed generation system for sudden variation in load demand, wind speed and solar radiation. The hybrid systems comprise of different renewable energy resources such as wind, photovoltaic (PV) fuel cell (FC) and diesel engine generator (DEG) along with the energy storage devices such as flywheel energy storage system (FESS) and battery energy storage system (BESS). Further ultracapacitors (UC) as an alternative energy storage element and interconnection of hybrid systems through tie-line is incorporated into the system for improved performance. A comparative assessment of deviation of frequency profile for different hybrid systems in the presence of different storage system combinations is carried out graphically as well as in terms of the performance index (PI), ie integral square error (ISE). Both qualitative and quantitative analysis reflects the improvements of the deviation in frequency profiles in the presence of the ultracapacitors (UC) as compared to other energy storage elements.

  17. Usability of small impact craters on small surface areas in crater count dating: Analysing examples from the Harmakhis Vallis outflow channel, Mars

    Science.gov (United States)

    Kukkonen, S.; Kostama, V.-P.

    2018-05-01

    The availability of very high-resolution images has made it possible to extend crater size-frequency distribution studies to small, deca/hectometer-scale craters. This has enabled the dating of small and young surface units, as well as recent, short-time and small-scale geologic processes that have occurred on the units. Usually, however, the higher the spatial resolution of space images is, the smaller area is covered by the images. Thus the use of single, very high-resolution images in crater count age determination may be debatable if the images do not cover the studied region entirely. Here we compare the crater count results for the floor of the Harmakhis Vallis outflow channel obtained from the images of the ConTeXt camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO). The CTX images enable crater counts for entire units on the Harmakhis Vallis main valley, whereas the coverage of the higher-resolution HiRISE images is limited and thus the images can only be used to date small parts of the units. Our case study shows that the crater count data based on small impact craters and small surface areas mainly correspond with the crater count data based on larger craters and more extensive counting areas on the same unit. If differences between the results were founded, they could usually be explained by the regional geology. Usually, these differences appeared when at least one cratering model age is missing from either of the crater datasets. On the other hand, we found only a few cases in which the cratering model ages were completely different. We conclude that the crater counts using small impact craters on small counting areas provide useful information about the geological processes which have modified the surface. However, it is important to remember that all the crater counts results obtained from a specific counting area always primarily represent the results from the counting area-not the whole

  18. Power System Oscillatory Behaviors: Sources, Characteristics, & Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Follum, James D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tuffner, Francis K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dosiek, Luke A. [Union College, Schenectady, NY (United States); Pierre, John W. [Univ. of Wyoming, Laramie, WY (United States)

    2017-05-17

    This document is intended to provide a broad overview of the sources, characteristics, and analyses of natural and forced oscillatory behaviors in power systems. These aspects are necessarily linked. Oscillations appear in measurements with distinguishing characteristics derived from the oscillation’s source. These characteristics determine which analysis methods can be appropriately applied, and the results from these analyses can only be interpreted correctly with an understanding of the oscillation’s origin. To describe oscillations both at their source within a physical power system and within measurements, a perspective from the boundary between power system and signal processing theory has been adopted.

  19. Metabolites in vertebrate Hedgehog signaling.

    Science.gov (United States)

    Roberg-Larsen, Hanne; Strand, Martin Frank; Krauss, Stefan; Wilson, Steven Ray

    2014-04-11

    The Hedgehog (HH) signaling pathway is critical in embryonic development, stem cell biology, tissue homeostasis, chemoattraction and synapse formation. Irregular HH signaling is associated with a number of disease conditions including congenital disorders and cancer. In particular, deregulation of HH signaling has been linked to skin, brain, lung, colon and pancreatic cancers. Key mediators of the HH signaling pathway are the 12-pass membrane protein Patched (PTC), the 7-pass membrane protein Smoothened (SMO) and the GLI transcription factors. PTC shares homology with the RND family of small-molecule transporters and it has been proposed that it interferes with SMO through metabolites. Although a conclusive picture is lacking, substantial efforts are made to identify and understand natural metabolites/sterols, including cholesterol, vitamin D3, oxysterols and glucocorticoides, that may be affected by, or influence the HH signaling cascade at the level of PTC and SMO. In this review we will elaborate the role of metabolites in HH signaling with a focus on oxysterols, and discuss advancements in modern analytical approaches in the field. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Poisson pre-processing of nonstationary photonic signals: Signals with equality between mean and variance.

    Science.gov (United States)

    Poplová, Michaela; Sovka, Pavel; Cifra, Michal

    2017-01-01

    Photonic signals are broadly exploited in communication and sensing and they typically exhibit Poisson-like statistics. In a common scenario where the intensity of the photonic signals is low and one needs to remove a nonstationary trend of the signals for any further analysis, one faces an obstacle: due to the dependence between the mean and variance typical for a Poisson-like process, information about the trend remains in the variance even after the trend has been subtracted, possibly yielding artifactual results in further analyses. Commonly available detrending or normalizing methods cannot cope with this issue. To alleviate this issue we developed a suitable pre-processing method for the signals that originate from a Poisson-like process. In this paper, a Poisson pre-processing method for nonstationary time series with Poisson distribution is developed and tested on computer-generated model data and experimental data of chemiluminescence from human neutrophils and mung seeds. The presented method transforms a nonstationary Poisson signal into a stationary signal with a Poisson distribution while preserving the type of photocount distribution and phase-space structure of the signal. The importance of the suggested pre-processing method is shown in Fano factor and Hurst exponent analysis of both computer-generated model signals and experimental photonic signals. It is demonstrated that our pre-processing method is superior to standard detrending-based methods whenever further signal analysis is sensitive to variance of the signal.

  1. Simultaneous acquisition of dual analyser-based phase contrast X-ray images for small animal imaging

    International Nuclear Information System (INIS)

    Kitchen, Marcus J.; Pavlov, Konstantin M.; Hooper, Stuart B.; Vine, David J.; Siu, Karen K.W.; Wallace, Megan J.; Siew, Melissa L.L.; Yagi, Naoto; Uesugi, Kentaro; Lewis, Rob A.

    2008-01-01

    Analyser-based phase contrast X-ray imaging can provide high-contrast images of biological tissues with exquisite sensitivity to the boundaries between tissues. The phase and absorption information can be extracted by processing multiple images acquired at different analyser orientations. Recording both the transmitted and diffracted beams from a thin Laue analyser crystal can make phase retrieval possible for dynamic systems by allowing full field imaging. This technique was used to image the thorax of a mechanically ventilated newborn rabbit pup using a 25 keV beam from the SPring-8 synchrotron radiation facility. The diffracted image was produced from the (1 1 1) planes of a 50 mm x 40 mm, 100 μm thick Si analyser crystal in the Laue geometry. The beam and analyser were large enough to image the entire chest, making it possible to observe changes in anatomy with high contrast and spatial resolution

  2. Simultaneous acquisition of dual analyser-based phase contrast X-ray images for small animal imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kitchen, Marcus J. [School of Physics, Monash University, Victoria 3800 (Australia)], E-mail: Marcus.Kitchen@sci.monash.edu.au; Pavlov, Konstantin M. [School of Physics, Monash University, Victoria 3800 (Australia); Monash Centre for Synchrotron Science, Monash University, Victoria 3800 (Australia); Physics and Electronics, School of Science and Technology, University of New England, NSW 2351 (Australia)], E-mail: Konstantin.Pavlov@sci.monash.edu.au; Hooper, Stuart B. [Department of Physiology, Monash University, Victoria 3800 (Australia)], E-mail: Stuart.Hooper@med.monash.edu.au; Vine, David J. [School of Physics, Monash University, Victoria 3800 (Australia)], E-mail: David.Vine@sci.monash.edu.au; Siu, Karen K.W. [School of Physics, Monash University, Victoria 3800 (Australia); Monash Centre for Synchrotron Science, Monash University, Victoria 3800 (Australia)], E-mail: Karen.Siu@sci.monash.edu.au; Wallace, Megan J. [Department of Physiology, Monash University, Victoria 3800 (Australia)], E-mail: Megan.Wallace@med.monash.edu.au; Siew, Melissa L.L. [Department of Physiology, Monash University, Victoria 3800 (Australia)], E-mail: Melissa.Siew@med.monash.edu.au; Yagi, Naoto [SPring-8/JASRI, Sayo (Japan)], E-mail: yagi@spring8.or.jp; Uesugi, Kentaro [SPring-8/JASRI, Sayo (Japan)], E-mail: ueken@spring8.or.jp; Lewis, Rob A. [School of Physics, Monash University, Victoria 3800 (Australia); Monash Centre for Synchrotron Science, Monash University, Victoria 3800 (Australia)], E-mail: Rob.Lewis@sync.monash.edu.au

    2008-12-15

    Analyser-based phase contrast X-ray imaging can provide high-contrast images of biological tissues with exquisite sensitivity to the boundaries between tissues. The phase and absorption information can be extracted by processing multiple images acquired at different analyser orientations. Recording both the transmitted and diffracted beams from a thin Laue analyser crystal can make phase retrieval possible for dynamic systems by allowing full field imaging. This technique was used to image the thorax of a mechanically ventilated newborn rabbit pup using a 25 keV beam from the SPring-8 synchrotron radiation facility. The diffracted image was produced from the (1 1 1) planes of a 50 mm x 40 mm, 100 {mu}m thick Si analyser crystal in the Laue geometry. The beam and analyser were large enough to image the entire chest, making it possible to observe changes in anatomy with high contrast and spatial resolution.

  3. New developments in microbial interspecies signaling.

    Science.gov (United States)

    Shank, Elizabeth Anne; Kolter, Roberto

    2009-04-01

    There is a growing appreciation that in addition to well-documented intraspecies quorum sensing systems, small molecules act as signals between microbes of different species. This review will focus on how bacterial small molecules modulate these interspecies interactions. We will particularly emphasize complex relationships such as those between microbes and insects, interactions resulting in non-antagonistic outcomes (i.e. developmental and morphological processes), how co-culture can lead to the discovery of new small molecules, and the use of known compounds to evoke unexpected responses and mediate crosstalk between microbes.

  4. Discrete frequency identification using the HP 5451B Fourier analyser

    International Nuclear Information System (INIS)

    Holland, L.; Barry, P.

    1977-01-01

    The frequency analysis by the HP5451B discrete frequency Fourier analyser is studied. The advantages of cross correlation analysis to identify discrete frequencies in a background noise are discussed in conjuction with the elimination of aliasing and wraparound error. Discrete frequency identification is illustrated by a series of graphs giving the results of analysing 'electrical' and 'acoustical' white noise and sinusoidal signals [pt

  5. Clinical development of galunisertib (LY2157299 monohydrate, a small molecule inhibitor of transforming growth factor-beta signaling pathway

    Directory of Open Access Journals (Sweden)

    Herbertz S

    2015-08-01

    Full Text Available Stephan Herbertz,1 J Scott Sawyer,2 Anja J Stauber,2 Ivelina Gueorguieva,3 Kyla E Driscoll,4 Shawn T Estrem,2 Ann L Cleverly,3 Durisala Desaiah,2 Susan C Guba,2 Karim A Benhadji,2 Christopher A Slapak,2 Michael M Lahn21Lilly Deutschland GmbH, Bad Homburg, Germany; 2Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA; 3Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK; 4Lilly Research Laboratories, Eli Lilly and Company, New York, NY, USA Abstract: Transforming growth factor-beta (TGF-β signaling regulates a wide range of biological processes. TGF-β plays an important role in tumorigenesis and contributes to the hallmarks of cancer, including tumor proliferation, invasion and metastasis, inflammation, angiogenesis, and escape of immune surveillance. There are several pharmacological approaches to block TGF-β signaling, such as monoclonal antibodies, vaccines, antisense oligonucleotides, and small molecule inhibitors. Galunisertib (LY2157299 monohydrate is an oral small molecule inhibitor of the TGF-β receptor I kinase that specifically downregulates the phosphorylation of SMAD2, abrogating activation of the canonical pathway. Furthermore, galunisertib has antitumor activity in tumor-bearing animal models such as breast, colon, lung cancers, and hepatocellular carcinoma. Continuous long-term exposure to galunisertib caused cardiac toxicities in animals requiring adoption of a pharmacokinetic/pharmacodynamic-based dosing strategy to allow further development. The use of such a pharmacokinetic/pharmacodynamic model defined a therapeutic window with an appropriate safety profile that enabled the clinical investigation of galunisertib. These efforts resulted in an intermittent dosing regimen (14 days on/14 days off, on a 28-day cycle of galunisertib for all ongoing trials. Galunisertib is being investigated either as monotherapy or in combination with standard antitumor regimens (including nivolumab

  6. Fitness cost of pheromone production in signaling female moths.

    Science.gov (United States)

    Harari, Ally R; Zahavi, Tirtza; Thiéry, Denis

    2011-06-01

    A secondary sexual character may act as an honest signal of the quality of the individual if the trait bears a cost and if its expression is phenotypically condition dependent. The cost of increasing the trait should be tolerable for individuals in good condition but not for those in a poor condition. The trait thus provides an honest signal of quality that enables the receiver to choose higher quality mates. Evidence for sex pheromones, which play a major role in shaping sexual evolution, inflicting a signaling cost is scarce. Here, we demonstrate that the amount of the major component of the pheromone in glands of Lobesia botrana (Lepidoptera) females at signaling time was significantly greater in large than in small females, that male moths preferred larger females as mates when responding to volatile signals, and small virgin females, but not large ones, exposed to conspecific pheromone, produced, when mated, significantly fewer eggs than nonexposed females. The latter indicates a condition-dependent cost of signaling. These results are in accordance with the predictions of condition-dependent honest signals. We therefore suggest that female signaling for males using sex pheromones bears a cost and thus calling may serve as honest advertisement for female quality. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  7. Quantitative proteomic assessment of very early cellular signaling events

    DEFF Research Database (Denmark)

    Dengjel, Joern; Akimov, Vyacheslav; Olsen, Jesper V

    2007-01-01

    Technical limitations have prevented proteomic analyses of events occurring less than 30 s after signal initiation. We developed an automated, continuous quench-flow system allowing quantitative proteomic assessment of very early cellular signaling events (qPACE) with a time resolution of 1 s...

  8. Analysing Logistic Management of Culinary Small and Medium Enterprises in Manado

    OpenAIRE

    Kerap, Stephenny Karen Rahel; Pangemanan, Sifried S; Tumiwa, Johan

    2017-01-01

    Small and Medium Enterprises have significant roles in developing Indonesia's economy. That is why developing SMEs is crucial to do and developing the whole power of SMEs should start from every single SME in Manado including empowering the core business process of SMEs including in culinary SMEs. In culinary SMEs, providing the food is the most critical aspect to do. This is where the logistic management became crucial as a business activity that supports the Production and Operation Managem...

  9. Analysis of acoustic sound signal for ONB measurement

    International Nuclear Information System (INIS)

    Park, S. J.; Kim, H. I.; Han, K. Y.; Chai, H. T.; Park, C.

    2003-01-01

    The onset of nucleate boiling (ONB) was measured in a test fuel bundle composed of several fuel element simulators (FES) by analysing the aquatic sound signals. In order measure ONBs, a hydrophone, a pre-amplifier, and a data acquisition system to acquire/process the aquatic signal was prepared. The acoustic signal generated in the coolant is converted to the current signal through the microphone. When the signal is analyzed in the frequency domain, each sound signal can be identified according to its origin of sound source. As the power is increased to a certain degree, a nucleate boiling is started. The frequent formation and collapse of the void bubbles produce sound signal. By measuring this sound signal one can pinpoint the ONB. Since the signal characteristics is identical for different mass flow rates, this method can be applicable for ascertaining ONB

  10. Understanding the statistics of small risks

    International Nuclear Information System (INIS)

    Siddall, E.

    1983-10-01

    Monte Carlo analyses are used to show what inferences can and cannot be drawn when either a very small number of accidents result from a considerable exposure or where a very small number of people, down to a single individual, are exposed to small added risks. The distinction between relative and absolute uncertainty is illustrated. No new statistical principles are involved

  11. HER2 induces cell proliferation and invasion of non-small-cell lung cancer by upregulating COX-2 expression via MEK/ERK signaling pathway

    Directory of Open Access Journals (Sweden)

    Chi F

    2016-05-01

    Full Text Available Feng Chi, Rong Wu, Xueying Jin, Min Jiang, Xike Zhu Department of Medical Oncology, Shengjing Hospital of China Medical University, Shenyang, People’s Republic of China Abstract: HER2 positivity has been well studied in various cancers, but its importance in non-small-cell lung cancer (NSCLC is still being explored. In this study, quantitative reverse transcription polymerase chain reaction (qRT-PCR was performed to detect HER2 and COX-2 expression in NSCLC tissues. Then, pcDNA3.1-HER2 was used to overexpress HER2, while HER2 siRNA and COX-2 siRNA were used to silence HER2 and COX-2 expression. MTT assay and invasion assay were used to detect the effects of HER2 on cell proliferation and invasion. Our study revealed that HER2 and COX-2 expression were upregulated in NSCLC tissues and HER2 exhibited a significant positive correlation with the levels of COX-2 expression. Overexpression of HER2 evidently elevated COX-2 expression, while silencing of HER2 evidently decreased COX-2 expression. Furthermore, overexpressed HER2 induced the ERK phosphorylation, and this was abolished by the treatment with U0126, a pharmacological inhibitor of MEK, an upstream kinase of ERK. HER2-induced expression and promoter activity of COX-2 were also suppressed by U0126, suggesting that the MEK/ERK signaling pathway regulates COX-2 expression. In addition, HER2 induced activation of AKT signaling pathway, which was reversed by pretreatment with U0126 and COX-2 siRNA. MTT and invasion assays revealed that HER2 induced cell proliferation and invasion that were reversed by pretreatment with U0126 and COX-2 siRNA. In this study, our results demonstrated for the first time that HER2 elevated COX-2 expression through the activation of MEK/ERK pathway, which subsequently induced cell proliferation and invasion via AKT pathway in NSCLC tissues. Keywords: HER2, MEK/ERK, COX-2, AKT signaling pathway, non-small-cell lung cancer

  12. Digital signal processing applied to crystal identification in Positron Emission Tomography dedicated to small animals

    Energy Technology Data Exchange (ETDEWEB)

    Fontaine, Rejean [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada)]. E-mail: Rejean.Fontaine@Usherbrooke.ca; Viscogliosi, Nicolas [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Semmaoui, Hicham [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Belanger, Francois [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Lemieux, Francois [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Tetrault, Marc-Andre [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Michaud, Jean-Baptiste [Department of Electrical and Computer Engineering, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Berard, Philippe [Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Cadorette, Jules [Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Pepin, Catherine M. [Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada); Lecomte, Roger [Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, 2500 Boul. Universite, Sherbrooke, Que., J1 K 2R1 (Canada)

    2007-02-01

    The recent introduction of all-digital electronic architecture in Positron Emission Tomography (PET) scanners, enables new paradigms to be explored for extracting relevant information from the detector signals, such as energy, time and crystal identification. The LabPET{sup TM} small animal scanner, which implements free-running 45-MHz sampling directly at the output of the charge sensitive preamplifiers, provides an excellent platform to test such advanced digital algorithms. A real-time identification method, based on an Auto-Regressive Moving-Average (ARMA) scheme, was tested for discriminating between LYSO (t{sub r}{approx}40 ns) and LGSO (t{sub r}{approx}65 ns) scintillators in phoswich detectors, coupled to a single Avalanche Photodiode (APD). Even with a low energy threshold of 250 keV applied individually, error rates<4% can be achieved, as compared to >10%, typically with conventional analog pulse shape discrimination techniques. Such digital crystal identification techniques can be readily implemented with phoswich detectors for improving spatial resolution in PET, either by increasing crystal pixellization or by mitigating parallax errors through depth-of-interaction determination. It also allows to reduce the event rate presented to the real-time coincidence engine by applying a low energy limit at the crystal granularity and rejecting more Compton photons.

  13. Identification of small molecules that disrupt signaling between ABL and its positive regulator RIN1.

    Directory of Open Access Journals (Sweden)

    Pamela Y Ting

    Full Text Available Constitutively active BCR-ABL kinase fusions are causative mutations in the pathogenesis of hematopoietic neoplasias including chronic myelogenous leukemia (CML. Although these fusions have been successfully targeted with kinase inhibitors, drug-resistance and relapse continue to limit long-term survival, highlighting the need for continued innovative drug discovery. We developed a time-resolved Förster resonance energy transfer (TR-FRET -based assay to identify compounds that disrupt stimulation of the ABL kinase by blocking its ability to bind the positive regulator RIN1. This assay was used in a high throughput screen (HTS of two small molecule libraries totaling 444,743 compounds. 708 confirmed hits were counter-screened to eliminate off-target inhibitors and reanalyzed to prioritize compounds with IC50 values below 10 μM. The CML cell line K562 was then used to identify five compounds that decrease MAPK1/3 phosphorylation, which we determined to be an indicator of RIN1-dependent ABL signaling. One of these compounds is a thiadiazole, and the other four are structurally related acyl piperidine amides. Notably, these five compounds lower cellular BCR-ABL1 kinase activity by blocking a positive regulatory interaction rather than directly inhibiting ABL catalytic function.

  14. Multifragmentation of heavy systems: partitions and phase transition signals; Multifragmentation de systemes lourds: partitions et signaux de transition de phases

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, E

    2006-09-15

    This work studies mononuclear systems produced in heavy ion collisions with large (peripheral: Au+Au) and small (central: Xe+Sn et Gd+U) impact parameters. These two classes of collisions need specific selections in order to isolate sources in thermal equilibrium (quasi-projectiles and quasi-fusion sources). We perform analyses on the statistical ensembles of events obtained after those selections to evidence phase transition signatures. First, a bimodal behaviour of the biggest fragment (Z{sub 1}) distribution, in peripheral collisions, is related to an order parameter using a renormalisation with an equiprobable excitation energy (E{sup *}) distribution constraint. A comparison with a canonical ensemble gives us information on the coexistence region location. Then, we compare static and dynamical properties of fragments produced by these sources in peripheral and central collisions. Differences on fragment multiplicities and charge asymmetry of partitions are observed. They find their origins in the presence or not of a velocity field mostly related to collective radial expansion during fragment formation. Analyses of the signal related to abnormal fluctuations of configurational energies and of the fossil signal related to spinodal decomposition for Au quasi-projectiles are performed to establish a link with the same signals already observed for central collisions. Finally, the location of events of the two types of sources in the E{sup *} - Z{sub 1} plane, are compared with a phase diagram, particularly the boundaries of the coexistence region deduced from the previous signals. (author)

  15. Signal Enhancement with Variable Span Linear Filters

    DEFF Research Database (Denmark)

    Benesty, Jacob; Christensen, Mads Græsbøll; Jensen, Jesper Rindom

    . Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal...... the time and STFT domains, and, lastly, in time-domain binaural enhancement. In these contexts, the properties of these filters are analyzed in terms of their noise reduction capabilities and desired signal distortion, and the analyses are validated and further explored in simulations....

  16. Opposing nodal and BMP signals regulate left-right asymmetry in the sea urchin larva.

    Directory of Open Access Journals (Sweden)

    Yi-Jyun Luo

    Full Text Available Nodal and BMP signals are important for establishing left-right (LR asymmetry in vertebrates. In sea urchins, Nodal signaling prevents the formation of the rudiment on the right side. However, the opposing pathway to Nodal signaling during LR axis establishment is not clear. Here, we revealed that BMP signaling is activated in the left coelomic pouch, specifically in the veg2 lineage, but not in the small micromeres. By perturbing BMP activities, we demonstrated that BMP signaling is required for activating the expression of the left-sided genes and the formation of the left-sided structures. On the other hand, Nodal signals on the right side inhibit BMP signaling and control LR asymmetric separation and apoptosis of the small micromeres. Our findings show that BMP signaling is the positive signal for left-sided development in sea urchins, suggesting that the opposing roles of Nodal and BMP signals in establishing LR asymmetry are conserved in deuterostomes.

  17. Tracking Small Satellites using Translated GPS

    OpenAIRE

    Lefevre, Don; Mulally, Daniel

    1991-01-01

    This paper discusses using translated GPS for tracking small satellites, the technical trade-offs involved, and the position and timing accuracies which are achievable using translated GPS. The Global Positioning System (GPS) uses the relative times-of-arrival of multiple spread-spectrum signals at an antenna to determine the position of the antenna. The system can also determine the time the antenna was at that position. The direct sequence spread spectrum signals are transmitted from GPS sa...

  18. A novel role for small molecule glycomimetics in the protection against lipid-induced endothelial dysfunction: Involvement of Akt/eNOS and Nrf2/ARE signaling.

    Science.gov (United States)

    Mahmoud, Ayman M; Wilkinson, Fiona L; Jones, Alan M; Wilkinson, James A; Romero, Miguel; Duarte, Juan; Alexander, M Yvonne

    2017-01-01

    Glycomimetics are a diverse array of saccharide-inspired compounds, designed to mimic the bioactive functions of glycosaminoglycans. Therefore, glycomimetics represent a unique source of novel therapies to target aberrant signaling and protein interactions in a wide range of diseases. We investigated the protective effects of four newly synthesized small molecule glycomimetics against lipid-induced endothelial dysfunction, with an emphasis on nitric oxide (NO) and oxidative stress. Four aromatic sugar mimetics were synthesized by the stepwise transformation of 2,5-dihydroxybenzoic acid to derivatives (C1-C4) incorporating sulfate groups to mimic the structure of heparan sulfate. Glycomimetic-treated human umbilical vein endothelial cells (HUVECs) were exposed to palmitic acid to model lipid-induced oxidative stress. Palmitate-induced impairment of NO production was restored by the glycomimetics, through activation of Akt/eNOS signaling. Furthermore, C1-C4 significantly inhibited palmitate-induced reactive oxygen species (ROS) production, lipid peroxidation, and activity and expression of NADPH oxidase. These effects were attributed to activation of the Nrf2/ARE pathway and downstream activation of cellular antioxidant and cytoprotective proteins. In ex vivo vascular reactivity studies, the glycomimetics (C1-C4) also demonstrated a significant improvement in endothelium-dependent relaxation and decreased ROS production and NADPH oxidase activity in isolated mouse thoracic aortic rings exposed to palmitate. The small molecule glycomimetics, C1-C4, protect against lipid-induced endothelial dysfunction through up-regulation of Akt/eNOS and Nrf2/ARE signaling pathways. Thus, carbohydrate-derived therapeutics are a new class of glycomimetic drugs targeting endothelial dysfunction, regarded as the first line of defense against vascular complications in cardiovascular disease. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. New small molecule inhibitors of UPR activation demonstrate that PERK, but not IRE1α signaling is essential for promoting adaptation and survival to hypoxia

    International Nuclear Information System (INIS)

    Cojocari, Dan; Vellanki, Ravi N.; Sit, Brandon; Uehling, David; Koritzinsky, Marianne; Wouters, Bradly G.

    2013-01-01

    Background and purpose: The unfolded protein response (UPR) is activated in response to hypoxia-induced stress in the endoplasmic reticulum (ER) and consists of three distinct signaling arms. Here we explore the potential of targeting two of these arms with new potent small-molecule inhibitors designed against IRE1α and PERK. Methods: We utilized shRNAs and small-molecule inhibitors of IRE1α (4μ8c) and PERK (GSK-compound 39). XBP1 splicing and DNAJB9 mRNA was measured by qPCR and was used to monitor IRE1α activity. PERK activity was monitored by immunoblotting eIF2α phosphorylation and qPCR of DDIT3 mRNA. Hypoxia tolerance was measured using proliferation and clonogenic cell survival assays of cells exposed to mild or severe hypoxia in the presence of the inhibitors. Results: Using knockdown experiments we show that PERK is essential for survival of KP4 cells while knockdown of IRE1α dramatically decreases the proliferation and survival of HCT116 during hypoxia. Further, we show that in response to both hypoxia and other ER stress-inducing agents both 4μ8c and the PERK inhibitor are selective and potent inhibitors of IRE1α and PERK activation, respectively. However, despite potent inhibition of IRE1α activation, 4μ8c had no effect on cell proliferation or clonogenic survival of cells exposed to hypoxia. This was in contrast to the inactivation of PERK signaling with the PERK inhibitor, which reduced tolerance to hypoxia and other ER stress inducing agents. Conclusions: Our results demonstrate that IRE1α but not its splicing activity is important for hypoxic cell survival. The PERK signaling arm is uniquely important for promoting adaptation and survival during hypoxia-induced ER stress and should be the focus of future therapeutic efforts

  20. An implantable CMOS signal conditioning system for recording nerve signals with cuff electrodes

    DEFF Research Database (Denmark)

    Papathanasiou, Konstantinos; Lehmann, Torsten

    2000-01-01

    We propose a system architecture for recording nerve signals with cuff electrodes and develop the key component in this system, the small-input, low-noise, low-power, high-gain amplifier. The amplifier is implemented using a mixture of weak- and strong-inversion transistors and a special off-set ......-set compensation technique; its performance is validated using Spice simulations....

  1. Cosmic microwave background polarization signals from tangled magnetic fields.

    Science.gov (United States)

    Seshadri, T R; Subramanian, K

    2001-09-03

    Tangled, primordial cosmic magnetic fields create small rotational velocity perturbations on the last scattering surface of the cosmic microwave background radiation. For fields which redshift to a present value of B0 = 3 x 10(-9) G, these vector modes are shown to generate polarization anisotropies of order 0.1-4 microK on small angular scales (500signals result for n = 2 spectra. Unlike inflation generated, scalar modes, these signals are dominated by the odd parity, B-type polarization, which could help in their detection.

  2. Gear wear monitoring by modulation signal bispectrum based on motor current signal analysis

    Science.gov (United States)

    Zhang, Ruiliang; Gu, Fengshou; Mansaf, Haram; Wang, Tie; Ball, Andrew D.

    2017-09-01

    Gears are important mechanical components for power transmissions. Tooth wear is one of the most common failure modes, which can present throughout a gear's lifetime. It is significant to accurately monitor gear wear progression in order to take timely predictive maintenances. Motor current signature analysis (MCSA) is an effective and non-intrusive approach which is able to monitor faults from both electrical and mechanical systems. However, little research has been reported in monitoring the gear wear and estimating its severity based on MCSA. This paper presents a novel gear wear monitoring method through a modulation signal bispectrum based motor current signal analysis (MSB-MCSA). For a steady gear transmission, it is inevitable to exist load and speed oscillations due to various errors including wears. These oscillations can induce small modulations in the current signals of the driving motor. MSB is particularly effective in characterising such small modulation signals. Based on these understandings, the monitoring process was implemented based on the current signals from a run-to-failure test of an industrial two stages helical gearbox under a moderate accelerated fatigue process. At the initial operation of the test, MSB analysis results showed that the peak values at the bifrequencies of gear rotations and the power supply can be effective monitoring features for identifying faulty gears and wear severity as they exhibit agreeable changes with gear loads. A monotonically increasing trend established by these features allows a clear indication of the gear wear progression. The dismantle inspection at 477 h of operation, made when one of the monitored features is about 123% higher than its baseline, has found that there are severe scuffing wear marks on a number of tooth surfaces on the driving gear, showing that the gear endures a gradual wear process during its long test operation. Therefore, it is affirmed that the MSB-MSCA approach proposed is reliable

  3. Redefining the functional roles of the gastrointestinal migrating motor complex and motilin in small bacterial overgrowth and hunger signaling.

    Science.gov (United States)

    Deloose, Eveline; Tack, Jan

    2016-02-15

    During the fasting state the upper gastrointestinal tract exhibits a specific periodic migrating contraction pattern that is known as the migrating motor complex (MMC). Three different phases can be distinguished during the MMC. Phase III of the MMC is the most active of the three and can start either in the stomach or small intestine. Historically this pattern was designated to be the housekeeper of the gut since disturbances in the pattern were associated with small intestinal bacterial overgrowth; however, its role in the involvement of hunger sensations was already hinted in the beginning of the 20th century by both Cannon (Cannon W, Washburn A. Am J Physiol 29: 441-454, 1912) and Carlson (Carlson A. The Control of Hunger in Health and Disease. Chicago, IL: Univ. of Chicago Press, 1916). The discovery of motilin in 1973 shed more light on the control mechanisms of the MMC. Motilin plasma levels fluctuate together with the phases of the MMC and induce phase III contractions with a gastric onset. Recent research suggests that these motilin-induced phase III contractions signal hunger in healthy subjects and that this system is disturbed in morbidly obese patients. This minireview describes the functions of the MMC in the gut and its regulatory role in controlling hunger sensations. Copyright © 2016 the American Physiological Society.

  4. An experimental digital consumer recorder for MPEG-coded video signals

    NARCIS (Netherlands)

    Saeijs, R.W.J.J.; With, de P.H.N.; Rijckaert, A.M.A.; Wong, C.

    1995-01-01

    The concept and real-time implementation of an experimental home-use digital recorder is presented, capable of recording MPEG-compressed video signals. The system has small recording mechanics based on the DVC standard and it uses MPEG compression for trick-mode signals as well

  5. Coordinated regulation by two VPS9 domain-containing guanine nucleotide exchange factors in small GTPase Rab5 signaling pathways in fission yeast

    International Nuclear Information System (INIS)

    Tsukamoto, Yuta; Kagiwada, Satoshi; Shimazu, Sayuri; Takegawa, Kaoru; Noguchi, Tetsuko; Miyamoto, Masaaki

    2015-01-01

    The small GTPase Rab5 is reported to regulate various cellular functions, such as vesicular transport and endocytosis. VPS9 domain-containing proteins are thought to activate Rab5(s) by their guanine-nucleotide exchange activities. Numerous VPS9 proteins have been identified and are structurally conserved from yeast to mammalian cells. However, the functional relationships among VPS9 proteins in cells remain unclear. Only one Rab5 and two VPS9 proteins were identified in the Schizosaccharomyces pombe genome. Here, we examined the cellular function of two VPS9 proteins and the relationship between these proteins in cellular functions. Vps901-GFP and Vps902-GFP exhibited dotted signals in vegetative and differentiated cells. vps901 deletion mutant (Δvps901) cells exhibited a phenotype deficient in the mating process and responses to high concentrations of ions, such as calcium and metals, and Δvps901Δvps902 double mutant cells exhibited round cell shapes similar to ypt5-909 (Rab5 mutant allele) cells. Deletion of both vps901 and vps902 genes completely abolished the mating process and responses to various stresses. A lack of vacuole formation and aberrant inner cell membrane structures were also observed in Δvps901Δvps902 cells by electron microscopy. These data strongly suggest that Vps901 and Vps902 are cooperatively involved in the regulation of cellular functions, such as cell morphology, sexual development, response to ion stresses, and vacuole formation, via Rab5 signaling pathways in fission yeast cells. - Highlights: • Roles of Rab5 activator VPS9 proteins in cellular functions. • Cooperation between VPS9 proteins in Rab5 signaling pathway. • Roles of each VPS9 protein in Rab5 signaling pathway are discussed

  6. Coordinated regulation by two VPS9 domain-containing guanine nucleotide exchange factors in small GTPase Rab5 signaling pathways in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Yuta [Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Kagiwada, Satoshi [Department of Biological Sciences, Faculty of Science, Nara Women' s University, Kitauoyanishi-machi, Nara 630-8506 (Japan); Shimazu, Sayuri [Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Takegawa, Kaoru [Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Noguchi, Tetsuko [Department of Biological Sciences, Faculty of Science, Nara Women' s University, Kitauoyanishi-machi, Nara 630-8506 (Japan); Miyamoto, Masaaki, E-mail: miya@kobe-u.ac.jp [Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan)

    2015-03-20

    The small GTPase Rab5 is reported to regulate various cellular functions, such as vesicular transport and endocytosis. VPS9 domain-containing proteins are thought to activate Rab5(s) by their guanine-nucleotide exchange activities. Numerous VPS9 proteins have been identified and are structurally conserved from yeast to mammalian cells. However, the functional relationships among VPS9 proteins in cells remain unclear. Only one Rab5 and two VPS9 proteins were identified in the Schizosaccharomyces pombe genome. Here, we examined the cellular function of two VPS9 proteins and the relationship between these proteins in cellular functions. Vps901-GFP and Vps902-GFP exhibited dotted signals in vegetative and differentiated cells. vps901 deletion mutant (Δvps901) cells exhibited a phenotype deficient in the mating process and responses to high concentrations of ions, such as calcium and metals, and Δvps901Δvps902 double mutant cells exhibited round cell shapes similar to ypt5-909 (Rab5 mutant allele) cells. Deletion of both vps901 and vps902 genes completely abolished the mating process and responses to various stresses. A lack of vacuole formation and aberrant inner cell membrane structures were also observed in Δvps901Δvps902 cells by electron microscopy. These data strongly suggest that Vps901 and Vps902 are cooperatively involved in the regulation of cellular functions, such as cell morphology, sexual development, response to ion stresses, and vacuole formation, via Rab5 signaling pathways in fission yeast cells. - Highlights: • Roles of Rab5 activator VPS9 proteins in cellular functions. • Cooperation between VPS9 proteins in Rab5 signaling pathway. • Roles of each VPS9 protein in Rab5 signaling pathway are discussed.

  7. Small-Signal Modeling, Stability Analysis and Design Optimization of Single-Phase Delay-Based PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Vidal, Ana

    2016-01-01

    Generally speaking, designing single-phase phaselocked loops (PLLs) is more complicated than three-phase ones, as their implementation often involves the generation of a fictitious orthogonal signal for the frame transformation. In recent years, many approaches to generate the orthogonal signal...... these issues and explore new methods to enhance their performance. The stability analysis, control design guidelines and performance comparison with the state-of-the-art PLLs are presented as well....

  8. Method for forecasting an earthquake from precursor signals

    International Nuclear Information System (INIS)

    Farnworth, D.F.

    1996-01-01

    A method for forecasting an earthquake from precursor signals by employing characteristic first electromagnetic signals, second, seismically induced electromagnetic signals, seismically induced mechanical signals, and infrasonic acoustic signals which have been observed to precede an earthquake. From a first electromagnetic signal, a magnitude, depth beneath the surface of the earth, distance, latitude, longitude, and first and second forecasts of the time of occurrence of the impending earthquake may be derived. From a second, seismically induced electromagnetic signal and the mechanical signal, third and fourth forecasts of the time of occurrence of an impending earthquake determined from the analysis above, a magnitude, depth beneath the surface of the earth and fourth and fifth forecasts of the time of occurrence of the impending earthquake may be derived. The forecasts of time available from the above analyses range from up to five weeks to substantially within one hour in advance of the earthquake. (author)

  9. Robust statistics for deterministic and stochastic gravitational waves in non-Gaussian noise. II. Bayesian analyses

    International Nuclear Information System (INIS)

    Allen, Bruce; Creighton, Jolien D.E.; Flanagan, Eanna E.; Romano, Joseph D.

    2003-01-01

    In a previous paper (paper I), we derived a set of near-optimal signal detection techniques for gravitational wave detectors whose noise probability distributions contain non-Gaussian tails. The methods modify standard methods by truncating or clipping sample values which lie in those non-Gaussian tails. The methods were derived, in the frequentist framework, by minimizing false alarm probabilities at fixed false detection probability in the limit of weak signals. For stochastic signals, the resulting statistic consisted of a sum of an autocorrelation term and a cross-correlation term; it was necessary to discard 'by hand' the autocorrelation term in order to arrive at the correct, generalized cross-correlation statistic. In the present paper, we present an alternative derivation of the same signal detection techniques from within the Bayesian framework. We compute, for both deterministic and stochastic signals, the probability that a signal is present in the data, in the limit where the signal-to-noise ratio squared per frequency bin is small, where the signal is nevertheless strong enough to be detected (integrated signal-to-noise ratio large compared to 1), and where the total probability in the non-Gaussian tail part of the noise distribution is small. We show that, for each model considered, the resulting probability is to a good approximation a monotonic function of the detection statistic derived in paper I. Moreover, for stochastic signals, the new Bayesian derivation automatically eliminates the problematic autocorrelation term

  10. Detection and Localization of Random Signals

    DEFF Research Database (Denmark)

    Sporring, Jon; Olsen, Niels Holm; Nielsen, Mads

    2003-01-01

    filtering techniques. It is therefore interesting to extend the application to objects with many but small degrees of freedom in their geometry. These geometric variations deteriorate the linear correlation signal, both regarding its strength and localization with multiple peaks from a single object...

  11. Ras signaling in aging and metabolic regulation.

    Science.gov (United States)

    Slack, Cathy

    2017-12-07

    Aberrant signal transduction downstream of the Ras GTPase has a well-established role in tumorigenesis. Mutations that result in hyperactivation of Ras are responsible for a third of all human cancers. Hence, small molecule inhibitors of the Ras signal transduction cascade have been under intense focus as potential cancer treatments. In both invertebrate and mammalian models, emerging evidence has also implicated components of the Ras signaling pathway in aging and metabolic regulation. Here, I review the current evidence for Ras signaling in these newly discovered roles highlighting the interactions between the Ras pathway and other longevity assurance mechanisms. Defining the role of Ras signaling in maintaining age-related health may have important implications for the development of interventions that could not only increase lifespan but also delay the onset and/or progression of age-related functional decline.

  12. Distributed traffic signal control using fuzzy logic

    Science.gov (United States)

    Chiu, Stephen

    1992-01-01

    We present a distributed approach to traffic signal control, where the signal timing parameters at a given intersection are adjusted as functions of the local traffic condition and of the signal timing parameters at adjacent intersections. Thus, the signal timing parameters evolve dynamically using only local information to improve traffic flow. This distributed approach provides for a fault-tolerant, highly responsive traffic management system. The signal timing at an intersection is defined by three parameters: cycle time, phase split, and offset. We use fuzzy decision rules to adjust these three parameters based only on local information. The amount of change in the timing parameters during each cycle is limited to a small fraction of the current parameters to ensure smooth transition. We show the effectiveness of this method through simulation of the traffic flow in a network of controlled intersections.

  13. DUAL INHIBITION OF PI3K/AKT AND mTOR SIGNALING IN HUMAN NON-SMALL CELL LUNG CANCER CELLS BY A DIETARY FLAVONOID FISETIN

    Science.gov (United States)

    Khan, Naghma; Afaq, Farrukh; Khusro, Fatima H.; Adhami, Vaqar Mustafa; Suh, Yewseok; Mukhtar, Hasan

    2011-01-01

    Lung cancer is one of the most commonly occurring malignancies. It has been reported that mTOR is phosphorylated in lung cancer and its activation was more frequent in tumors with over-expression of PI3K/Akt. Therefore, dual inhibitors of PI3K/Akt and mTOR signaling could be valuable agents for treating lung cancer. In the present study, we show that fisetin, a dietary tetrahydroxyflavone inhibits cell-growth with the concomitant suppression of PI3K/Akt and mTOR signaling in human non-small cell lung cancer (NSCLC) cells. Using autodock 4, we found that fisetin physically interacts with the mTOR complex at two sites. Fisetin treatment was also found to reduce the formation of A549 cell colonies in a dose-dependent manner. Treatment of cells with fisetin caused decrease in the protein expression of PI3K (p85 and p110), inhibition of phosphorylation of Akt, mTOR, p70S6K1, eIF-4E and 4E-BP1. Fisetin-treated cells also exhibited dose-dependent inhibition of the constituents of mTOR signaling complex like Rictor, Raptor, GβL and PRAS40. There was increase in the phosphorylation of AMPKα and decrease in the phosphorylation of TSC2 on treatment of cells with fisetin. We also found that treatment of cells with mTOR inhibitor rapamycin and mTOR-siRNA caused decrease in phosphorylation of mTOR and its target proteins which were further downregulated on treatment with fisetin, suggesting that these effects are mediated in part, through mTOR signaling. Our results show that fisetin suppressed PI3K/Akt and mTOR signaling in NSCLC cells and thus, could be developed as a chemotherapeutic agent against human lung cancer. PMID:21618507

  14. Estimation of neural energy in microelectrode signals

    Science.gov (United States)

    Gaumond, R. P.; Clement, R.; Silva, R.; Sander, D.

    2004-09-01

    We considered the problem of determining the neural contribution to the signal recorded by an intracortical electrode. We developed a linear least-squares approach to determine the energy fraction of a signal attributable to an arbitrary number of autocorrelation-defined signals buried in noise. Application of the method requires estimation of autocorrelation functions Rap(tgr) characterizing the action potential (AP) waveforms and Rn(tgr) characterizing background noise. This method was applied to the analysis of chronically implanted microelectrode signals from motor cortex of rat. We found that neural (AP) energy consisted of a large-signal component which grows linearly with the number of threshold-detected neural events and a small-signal component unrelated to the count of threshold-detected AP signals. The addition of pseudorandom noise to electrode signals demonstrated the algorithm's effectiveness for a wide range of noise-to-signal energy ratios (0.08 to 39). We suggest, therefore, that the method could be of use in providing a measure of neural response in situations where clearly identified spike waveforms cannot be isolated, or in providing an additional 'background' measure of microelectrode neural activity to supplement the traditional AP spike count.

  15. Gallic acid inhibits gastric cancer cells metastasis and invasive growth via increased expression of RhoB, downregulation of AKT/small GTPase signals and inhibition of NF-κB activity

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Hsieh-Hsun [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China); Chang, Chi-Sen [Department of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Division of Gastroenterology, Taichung Veterans General Hospital, Taichung 402, Taiwan (China); Ho, Wei-Chi [Division of Gastroenterology, Jen-Ai Hospital, Taichung 402, Taiwan (China); Liao, Sheng-You [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China); Lin, Wea-Lung [Department of Pathology, School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Pathology, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Wang, Chau-Jong, E-mail: wcj@csmu.edu.tw [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Medical Research, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2013-01-01

    Our previous study demonstrated the therapeutic potential of gallic acid (GA) for controlling tumor metastasis through its inhibitory effect on the motility of AGS cells. A noteworthy finding in our previous experiment was increased RhoB expression in GA-treated cells. The aim of this study was to evaluate the role of RhoB expression on the inhibitory effects of GA on AGS cells. By applying the transfection of RhoB siRNA into AGS cells and an animal model, we tested the effect of GA on inhibition of tumor growth and RhoB expression. The results confirmed that RhoB-siRNA transfection induced GA to inhibit AGS cells’ invasive growth involving blocking the AKT/small GTPase signals pathway and inhibition of NF-κB activity. Finally, we evaluated the effect of GA on AGS cell metastasis by colonization of tumor cells in nude mice. It showed GA inhibited tumor cells growth via the expression of RhoB. These data support the inhibitory effect of GA which was shown to inhibit gastric cancer cell metastasis and invasive growth via increased expression of RhoB, downregulation of AKT/small GTPase signals and inhibition of NF-κB activity. Thus, GA might be a potential agent in treating gastric cancer. Highlights: ► GA could downregulate AKT signal via increased expression of RhoB. ► GA inhibits metastasis in vitro in gastric carcinoma. ► GA inhibits tumor growth in nude mice model.

  16. Acoustic detection for small-leak sodium-water reaction

    International Nuclear Information System (INIS)

    Nei, Hiromichi; Ohshima, Iwao; Ujihara, Kozaburo; Hori, Masao

    1977-01-01

    Characteristics of acoustic signal produced by sodium-water reaction due to steam injection and by Ar gas injection into sodium were experimentally investigated. Acoustic signal was measured by using Kistler 808A and 815A5 accelerometers. Root mean square (RMS) measurements and frequency analysis of the signal were conducted. The RMS measurements could detect a small water leakage into sodium, as small as 0.07g/sec, in the present loop. The peaks in a frequency spectrum were caused by the natural vibration of a rod on which the acoustic transducer was mounted. The RMS was approximately proportional to the one-third power of the steam leak rate and increased to some extent with the ambient sodium temperature. RMS values, both for sodium-water reaction and Ar gas injection, were about the same order of magnitude, when the data were plotted against the volumetric flow rates of steam and Argas. (auth.)

  17. Fisetin induces apoptosis and endoplasmic reticulum stress in human non-small cell lung cancer through inhibition of the MAPK signaling pathway.

    Science.gov (United States)

    Kang, Kyoung Ah; Piao, Mei Jing; Madduma Hewage, Susara Ruwan Kumara; Ryu, Yea Seong; Oh, Min Chang; Kwon, Taeg Kyu; Chae, Sungwook; Hyun, Jin Won

    2016-07-01

    Fisetin (3,3',4',7-tetrahydroxyflavone), a dietary flavonoid compound, is currently being investigated for its anticancer effect in various cancer models, including lung cancer. Recent studies show that fisetin induces cell growth inhibition and apoptosis in the human non-small cell lung cancer line NCI-H460. In this study, we investigated whether fisetin can induce endoplasmic reticulum (ER) stress-mediated apoptosis in NCI-H460 cells. Fisetin induced mitochondrial reactive oxygen species (ROS) and characteristic signs of ER stress: ER staining; mitochondrial Ca(2+) overload; expression of ER stress-related proteins; glucose-regulated protein (GRP)-78, phosphorylation of protein kinase RNA (PKR)-like endoplasmic reticulum kinase (PERK) and phosphorylation of eukaryotic initiation factor-2 α subunit; cleavage of activating transcription factor-6; phosphorylation of inositol-requiring kinase-1 and splicing of X-box transcription factor-1; induction of C/EBP homologous protein and cleaved caspase-12. siRNA-mediated knockdown of CHOP and ATF-6 attenuated fisetin-induced apoptotic cell death. In addition, fisetin induced phosphorylation of ERK, JNK, and p38 MAPK. Moreover, silencing of the MAPK signaling pathway prevented apoptotic cell death. In summary, our results indicate that, in NCI-H460 cells, fisetin induces apoptosis and ER stress that is mediated by induction of the MAPK signaling pathway.

  18. Analysing harmonic motions with an iPhone’s magnetometer

    Science.gov (United States)

    Yavuz, Ahmet; Kağan Temiz, Burak

    2016-05-01

    In this paper, we propose an experiment for analysing harmonic motion using an iPhone’s (or iPad’s) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone’s magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone’s screen using the Sensor Kinetics application. Data from this application was analysed with Eureqa software to establish the equation of the harmonic motion. Analyses show that the use of an iPhone’s magnetometer to analyse harmonic motion is a practical and effective method for small oscillations and frequencies less than 15-20 Hz.

  19. System and Method for Multi-Wavelength Optical Signal Detection

    Science.gov (United States)

    McGlone, Thomas D. (Inventor)

    2017-01-01

    The system and method for multi-wavelength optical signal detection enables the detection of optical signal levels significantly below those processed at the discrete circuit level by the use of mixed-signal processing methods implemented with integrated circuit technologies. The present invention is configured to detect and process small signals, which enables the reduction of the optical power required to stimulate detection networks, and lowers the required laser power to make specific measurements. The present invention provides an adaptation of active pixel networks combined with mixed-signal processing methods to provide an integer representation of the received signal as an output. The present invention also provides multi-wavelength laser detection circuits for use in various systems, such as a differential absorption light detection and ranging system.

  20. Signal correlations in biomass combustion. An information theoretic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruusunen, M.

    2013-09-01

    Increasing environmental and economic awareness are driving the development of combustion technologies to efficient biomass use and clean burning. To accomplish these goals, quantitative information about combustion variables is needed. However, for small-scale combustion units the existing monitoring methods are often expensive or complex. This study aimed to quantify correlations between flue gas temperatures and combustion variables, namely typical emission components, heat output, and efficiency. For this, data acquired from four small-scale combustion units and a large circulating fluidised bed boiler was studied. The fuel range varied from wood logs, wood chips, and wood pellets to biomass residue. Original signals and a defined set of their mathematical transformations were applied to data analysis. In order to evaluate the strength of the correlations, a multivariate distance measure based on information theory was derived. The analysis further assessed time-varying signal correlations and relative time delays. Ranking of the analysis results was based on the distance measure. The uniformity of the correlations in the different data sets was studied by comparing the 10-quantiles of the measured signal. The method was validated with two benchmark data sets. The flue gas temperatures and the combustion variables measured carried similar information. The strongest correlations were mainly linear with the transformed signal combinations and explicable by the combustion theory. Remarkably, the results showed uniformity of the correlations across the data sets with several signal transformations. This was also indicated by simulations using a linear model with constant structure to monitor carbon dioxide in flue gas. Acceptable performance was observed according to three validation criteria used to quantify modelling error in each data set. In general, the findings demonstrate that the presented signal transformations enable real-time approximation of the studied

  1. Nonstationary signals phase-energy approach-theory and simulations

    CERN Document Server

    Klein, R; Braun, S; 10.1006/mssp.2001.1398

    2001-01-01

    Modern time-frequency methods are intended to deal with a variety of nonstationary signals. One specific class, prevalent in the area of rotating machines, is that of harmonic signals of varying frequencies and amplitude. This paper presents a new adaptive phase-energy (APE) approach for time-frequency representation of varying harmonic signals. It is based on the concept of phase (frequency) paths and the instantaneous power spectral density (PSD). It is this path which represents the dynamic behaviour of the system generating the observed signal. The proposed method utilises dynamic filters based on an extended Nyquist theorem, enabling extraction of signal components with optimal signal-to-noise ratio. The APE detects the most energetic harmonic components (frequency paths) in the analysed signal. Tests on simulated signals show the superiority of the APE in resolution and resolving power as compared to STFT and wavelets wave- packet decomposition. The dynamic filters also enable the reconstruction of the ...

  2. Spectral components of laser Doppler flowmetry signals recorded in healthy and type 1 diabetic subjects at rest and during a local and progressive cutaneous pressure application: scalogram analyses

    International Nuclear Information System (INIS)

    Humeau, Anne; Koitka, Audrey; Abraham, Pierre; Saumet, Jean-Louis; L'Huillier, Jean-Pierre

    2004-01-01

    A significant transient increase in laser Doppler flowmetry (LDF) signals is observed in response to a local and progressive cutaneous pressure application in healthy subjects. This reflex may be impaired in diabetic patients. The work presents a signal processing providing the clarification of this phenomenon. Scalogram analyses of LDF signals recorded at rest and during a local and progressive cutaneous pressure application are performed on healthy and type 1 diabetic subjects. Three frequency bands, corresponding to myogenic, neurogenic and endothelial related metabolic activities, are studied. The results show that, at rest, the scalogram energy of each frequency band is significantly lower for diabetic patients than for healthy subjects, but the scalogram relative energies do not show any statistical difference between the two groups. Moreover, the neurogenic and endothelial related metabolic activities are significantly higher during the progressive pressure than at rest, in healthy and diabetic subjects. However, the relative contribution of the endothelial related metabolic activity is significantly higher during the progressive pressure than at rest, in the interval 200-400 s following the beginning of the pressure application, but only for healthy subjects. These results may improve knowledge on cutaneous microvascular responses to injuries or local pressures initiating diabetic complications

  3. Spectral components of laser Doppler flowmetry signals recorded in healthy and type 1 diabetic subjects at rest and during a local and progressive cutaneous pressure application: scalogram analyses

    Energy Technology Data Exchange (ETDEWEB)

    Humeau, Anne [Groupe ISAIP-ESAIP, 18 rue du 8 mai 1945, BP 80022, 49180 Saint Barthelemy d' Anjou cedex (France); Koitka, Audrey [Laboratoire de Physiologie et d' Explorations Vasculaires, Centre Hospitalier Universitaire d' Angers, 49033 Angers cedex 01 (France); Abraham, Pierre [Laboratoire de Physiologie et d' Explorations Vasculaires, Centre Hospitalier Universitaire d' Angers, 49033 Angers cedex 01 (France); Saumet, Jean-Louis [Laboratoire de Physiologie et d' Explorations Vasculaires, Centre Hospitalier Universitaire d' Angers, 49033 Angers cedex 01 (France); L' Huillier, Jean-Pierre [Ecole Nationale Superieure d' Arts et Metiers (ENSAM), Laboratoire Procedes-Materiaux-Instrumentation (LPMI), 2 boulevard du Ronceray, BP 3525, 49035 Angers cedex (France)

    2004-09-07

    A significant transient increase in laser Doppler flowmetry (LDF) signals is observed in response to a local and progressive cutaneous pressure application in healthy subjects. This reflex may be impaired in diabetic patients. The work presents a signal processing providing the clarification of this phenomenon. Scalogram analyses of LDF signals recorded at rest and during a local and progressive cutaneous pressure application are performed on healthy and type 1 diabetic subjects. Three frequency bands, corresponding to myogenic, neurogenic and endothelial related metabolic activities, are studied. The results show that, at rest, the scalogram energy of each frequency band is significantly lower for diabetic patients than for healthy subjects, but the scalogram relative energies do not show any statistical difference between the two groups. Moreover, the neurogenic and endothelial related metabolic activities are significantly higher during the progressive pressure than at rest, in healthy and diabetic subjects. However, the relative contribution of the endothelial related metabolic activity is significantly higher during the progressive pressure than at rest, in the interval 200-400 s following the beginning of the pressure application, but only for healthy subjects. These results may improve knowledge on cutaneous microvascular responses to injuries or local pressures initiating diabetic complications.

  4. Large-signal stability analysis of PWM converters

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, P.T. [Philips Labs., Briarcliff Manor, NY (United States); Cho, B.H. [Seoul National Univ. (Korea, Republic of). Dept. of Electrical Engineering

    1995-12-31

    Investigation of the effects of existing nonlinearities on the stability of PWM converters is performed. The bilinear structure, the duty cycle saturation, and the opamp saturation are the principal nonlinearities in PWM converters. These nonlinearities are incorporated in the large-signal analytical models of PWM converters, and the basic input-output stability theory is applied to analyze their stability. Design and optimization of the small-signal loop gains to counteract the undesirable nonlinear effects are also discussed.

  5. Structural analyses of sucrose laurate regioisomers by mass spectrometry techniques

    DEFF Research Database (Denmark)

    Lie, Aleksander; Stensballe, Allan; Pedersen, Lars Haastrup

    2015-01-01

    6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore the physic......6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore.......8, respectively, and Orbitrap HRMS confirmed the mass of [M+Na]+ (m/z 547.2712). ESI-MS/MS on the precursor ion [M+Na]+ resulted in product ion mass spectra showing two high-intensity signals for each sample. 6-O-Lauroyl sucrose produced signals located at m/z 547.27 and m/z 385.21, corresponding to the 6-O...

  6. Hedgehog Signaling in Endochondral Ossification

    Directory of Open Access Journals (Sweden)

    Shinsuke Ohba

    2016-06-01

    Full Text Available Hedgehog (Hh signaling plays crucial roles in the patterning and morphogenesis of various organs within the bodies of vertebrates and insects. Endochondral ossification is one of the notable developmental events in which Hh signaling acts as a master regulator. Among three Hh proteins in mammals, Indian hedgehog (Ihh is known to work as a major Hh input that induces biological impact of Hh signaling on the endochondral ossification. Ihh is expressed in prehypertrophic and hypertrophic chondrocytes of developing endochondral bones. Genetic studies so far have demonstrated that the Ihh-mediated activation of Hh signaling synchronizes chondrogenesis and osteogenesis during endochondral ossification by regulating the following processes: (1 chondrocyte differentiation; (2 chondrocyte proliferation; and (3 specification of bone-forming osteoblasts. Ihh not only forms a negative feedback loop with parathyroid hormone-related protein (PTHrP to maintain the growth plate length, but also directly promotes chondrocyte propagation. Ihh input is required for the specification of progenitors into osteoblast precursors. The combinatorial approaches of genome-wide analyses and mouse genetics will facilitate understanding of the regulatory mechanisms underlying the roles of Hh signaling in endochondral ossification, providing genome-level evidence of the potential of Hh signaling for the treatment of skeletal disorders.

  7. Hedgehog Signaling in Endochondral Ossification

    Science.gov (United States)

    Ohba, Shinsuke

    2016-01-01

    Hedgehog (Hh) signaling plays crucial roles in the patterning and morphogenesis of various organs within the bodies of vertebrates and insects. Endochondral ossification is one of the notable developmental events in which Hh signaling acts as a master regulator. Among three Hh proteins in mammals, Indian hedgehog (Ihh) is known to work as a major Hh input that induces biological impact of Hh signaling on the endochondral ossification. Ihh is expressed in prehypertrophic and hypertrophic chondrocytes of developing endochondral bones. Genetic studies so far have demonstrated that the Ihh-mediated activation of Hh signaling synchronizes chondrogenesis and osteogenesis during endochondral ossification by regulating the following processes: (1) chondrocyte differentiation; (2) chondrocyte proliferation; and (3) specification of bone-forming osteoblasts. Ihh not only forms a negative feedback loop with parathyroid hormone-related protein (PTHrP) to maintain the growth plate length, but also directly promotes chondrocyte propagation. Ihh input is required for the specification of progenitors into osteoblast precursors. The combinatorial approaches of genome-wide analyses and mouse genetics will facilitate understanding of the regulatory mechanisms underlying the roles of Hh signaling in endochondral ossification, providing genome-level evidence of the potential of Hh signaling for the treatment of skeletal disorders. PMID:29615586

  8. Examen d'analyses récentes portant sur l'Étude canadienne sur l'incidence des signalements de cas de violence et de négligence envers les enfants (ECI

    Directory of Open Access Journals (Sweden)

    D. Potter

    2015-01-01

    Full Text Available Introduction : Cette analyse a comme objectif de rassembler les articles évalués par les pairs utilisant des données tirées de l'Étude canadienne sur l'incidence des signalements de cas de violence et de négligence envers les enfants (ECI publiées depuis novembre 2011 ainsi que des suréchantillons provinciaux de l'ECI, d'évaluer la qualité de leurs conclusions, de les synthétiser et de faire le bilan des variations dans l'utilisation de ces données. Méthodologie : Nous avons sélectionné les articles au moyen du suivi des demandes d'accès aux données de l'ECI effectué par l'Agence de la santé publique du Canada et au suivi des publications produites au moyen de ces données. Deux évaluateurs au moins ont examiné de façon indépendante les articles et en ont évalué la qualité. Résultats : Nous avons conservé 32 articles. Leurs points forts étaient en général les suivants : objectifs de recherche clairement établis, variables de contrôle appropriées, analyses pertinentes, taille de l'échantillon suffisante, conclusions pertinentes et utilité pour les pratiques et politiques. Leur point problématique était le plus souvent une définition floue des variables et des critères d'inclusion des cas. La plupart du temps, les articles mesuraient les associations entre les caractéristiques des mauvais traitements et celles des enfants, des pourvoyeurs de soins, du ménage et de l'organisme ou de la personne à l'origine du signalement et ils s'intéressaient aux conséquences des signalements, par exemple l'ouverture d'un dossier pour une prestation continue de services ou le placement. Conclusion : Les articles utilisant des données de l'ECI ont obtenu des scores positifs pour la plupart des indicateurs de qualité. Dans leurs analyses les plus récentes, les chercheurs se sont concentrés sur les catégories de maltraitance insuffisamment étudiées jusqu'ici (exposition à la violence conjugale, négligence et

  9. Syndecans, signaling, and cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Woods, A

    1996-01-01

    structures within the heparan sulfate chains, leaving the roles of chondroitin sulfate chains and extracellular portion of the core proteins to be elucidated. Evidence that syndecans are a class of receptor involved in cell adhesion is mounting, and their small cytoplasmic domains may link...... transmembrane signaling from matrix to cytoskeleton, as proposed for other classes of adhesion receptors....

  10. Gain and loss of polyadenylation signals during evolution of green algae

    Directory of Open Access Journals (Sweden)

    Glöckner Gernot

    2007-04-01

    Full Text Available Abstract Background The Viridiplantae (green algae and land plants consist of two monophyletic lineages: the Chlorophyta and the Streptophyta. Most green algae belong to the Chlorophyta, while the Streptophyta include all land plants and a small group of freshwater algae known as Charophyceae. Eukaryotes attach a poly-A tail to the 3' ends of most nuclear-encoded mRNAs. In embryophytes, animals and fungi, the signal for polyadenylation contains an A-rich sequence (often AAUAAA or related sequence 13 to 30 nucleotides upstream from the cleavage site, which is commonly referred to as the near upstream element (NUE. However, it has been reported that the pentanucleotide UGUAA is used as polyadenylation signal for some genes in volvocalean algae. Results We set out to investigate polyadenylation signal differences between streptophytes and chlorophytes that may have emerged shortly after the evolutionary split between Streptophyta and Chlorophyta. We therefore analyzed expressed genes (ESTs from three streptophyte algae, Mesostigma viride, Klebsormidium subtile and Coleochaete scutata, and from two early-branching chlorophytes, Pyramimonas parkeae and Scherffelia dubia. In addition, to extend the database, our analyses included ESTs from six other chlorophytes (Acetabularia acetabulum, Chlamydomonas reinhardtii, Helicosporidium sp. ex Simulium jonesii, Prototheca wickerhamii, Scenedesmus obliquus and Ulva linza and one streptophyte (Closterium peracerosum. Our results indicate that polyadenylation signals in green algae vary widely. The UGUAA motif is confined to late-branching Chlorophyta. Most streptophyte algae do not have an A-rich sequence motif like that in embryophytes, animals and fungi. We observed polyadenylation signals similar to those of Arabidopsis and other land plants only in Mesostigma. Conclusion Polyadenylation signals in green algae show considerable variation. A new NUE (UGUAA was invented in derived chlorophytes and replaced

  11. Gain and loss of polyadenylation signals during evolution of green algae.

    Science.gov (United States)

    Wodniok, Sabina; Simon, Andreas; Glöckner, Gernot; Becker, Burkhard

    2007-04-18

    The Viridiplantae (green algae and land plants) consist of two monophyletic lineages: the Chlorophyta and the Streptophyta. Most green algae belong to the Chlorophyta, while the Streptophyta include all land plants and a small group of freshwater algae known as Charophyceae. Eukaryotes attach a poly-A tail to the 3' ends of most nuclear-encoded mRNAs. In embryophytes, animals and fungi, the signal for polyadenylation contains an A-rich sequence (often AAUAAA or related sequence) 13 to 30 nucleotides upstream from the cleavage site, which is commonly referred to as the near upstream element (NUE). However, it has been reported that the pentanucleotide UGUAA is used as polyadenylation signal for some genes in volvocalean algae. We set out to investigate polyadenylation signal differences between streptophytes and chlorophytes that may have emerged shortly after the evolutionary split between Streptophyta and Chlorophyta. We therefore analyzed expressed genes (ESTs) from three streptophyte algae, Mesostigma viride, Klebsormidium subtile and Coleochaete scutata, and from two early-branching chlorophytes, Pyramimonas parkeae and Scherffelia dubia. In addition, to extend the database, our analyses included ESTs from six other chlorophytes (Acetabularia acetabulum, Chlamydomonas reinhardtii, Helicosporidium sp. ex Simulium jonesii, Prototheca wickerhamii, Scenedesmus obliquus and Ulva linza) and one streptophyte (Closterium peracerosum). Our results indicate that polyadenylation signals in green algae vary widely. The UGUAA motif is confined to late-branching Chlorophyta. Most streptophyte algae do not have an A-rich sequence motif like that in embryophytes, animals and fungi. We observed polyadenylation signals similar to those of Arabidopsis and other land plants only in Mesostigma. Polyadenylation signals in green algae show considerable variation. A new NUE (UGUAA) was invented in derived chlorophytes and replaced not only the A-rich NUE but the complete poly

  12. Time-Frequency Analysis of Signals Generated by Rotating Machines

    Directory of Open Access Journals (Sweden)

    R. Zetik

    1999-06-01

    Full Text Available This contribution is devoted to the higher order time-frequency analyses of signals. Firstly, time-frequency representations of higher order (TFRHO are defined. Then L-Wigner distribution (LWD is given as a special case of TFRHO. Basic properties of LWD are illustrated based on the analysis of mono-component and multi-component synthetic signals and acoustical signals generated by rotating machine. The obtained results confirm usefulness of LWD application for the purpose of rotating machine condition monitoring.

  13. Nucleic acids encoding phloem small RNA-binding proteins and transgenic plants comprising them

    Science.gov (United States)

    Lucas, William J.; Yoo, Byung-Chun; Lough, Tony J.; Varkonyi-Gasic, Erika

    2007-03-13

    The present invention provides a polynucleotide sequence encoding a component of the protein machinery involved in small RNA trafficking, Cucurbita maxima phloem small RNA-binding protein (CmPSRB 1), and the corresponding polypeptide sequence. The invention also provides genetic constructs and transgenic plants comprising the polynucleotide sequence encoding a phloem small RNA-binding protein to alter (e.g., prevent, reduce or elevate) non-cell autonomous signaling events in the plants involving small RNA metabolism. These signaling events are involved in a broad spectrum of plant physiological and biochemical processes, including, for example, systemic resistance to pathogens, responses to environmental stresses, e.g., heat, drought, salinity, and systemic gene silencing (e.g., viral infections).

  14. Integrative genome analyses identify key somatic driver mutations of small-cell lung cancer

    NARCIS (Netherlands)

    Peifer, Martin; Fernandez-Cuesta, Lynnette; Sos, Martin L.; George, Julie; Seidel, Danila; Kasper, Lawryn H.; Plenker, Dennis; Leenders, Frauke; Sun, Ruping; Zander, Thomas; Menon, Roopika; Koker, Mirjam; Dahmen, Ilona; Mueller, Christian; Di Cerbo, Vincenzo; Schildhaus, Hans-Ulrich; Altmueller, Janine; Baessmann, Ingelore; Becker, Christian; de Wilde, Bram; Vandesompele, Jo; Boehm, Diana; Ansen, Sascha; Gabler, Franziska; Wilkening, Ines; Heynck, Stefanie; Heuckmann, Johannes M.; Lu, Xin; Carter, Scott L.; Cibulskis, Kristian; Banerji, Shantanu; Getz, Gad; Park, Kwon-Sik; Rauh, Daniel; Gruetter, Christian; Fischer, Matthias; Pasqualucci, Laura; Wright, Gavin; Wainer, Zoe; Russell, Prudence; Petersen, Iver; Chen, Yuan; Stoelben, Erich; Ludwig, Corinna; Schnabel, Philipp; Hoffmann, Hans; Muley, Thomas; Brockmann, Michael; Engel-Riedel, Walburga; Muscarella, Lucia A.; Fazio, Vito M.; Groen, Harry; Timens, Wim; Sietsma, Hannie; Thunnissen, Erik; Smit, Egbert; Heideman, Danielle A. M.; Snijders, Peter J. F.; Cappuzzo, Federico; Ligorio, Claudia; Damiani, Stefania; Field, John; Solberg, Steinar; Brustugun, Odd Terje; Lund-Iversen, Marius; Saenger, Joerg; Clement, Joachim H.; Soltermann, Alex; Moch, Holger; Weder, Walter; Solomon, Benjamin; Soria, Jean-Charles; Validire, Pierre; Besse, Benjamin; Brambilla, Elisabeth; Brambilla, Christian; Lantuejoul, Sylvie; Lorimier, Philippe; Schneider, Peter M.; Hallek, Michael; Pao, William; Meyerson, Matthew; Sage, Julien; Shendure, Jay; Schneider, Robert; Buettner, Reinhard; Wolf, Juergen; Nuernberg, Peter; Perner, Sven; Heukamp, Lukas C.; Brindle, Paul K.; Haas, Stefan; Thomas, Roman K.

    2012-01-01

    Small-cell lung cancer (SCLC) is an aggressive lung tumor subtype with poor prognosis(1-3). We sequenced 29 SCLC exomes, 2 genomes and 15 transcriptomes and found an extremely high mutation rate of 7.4 +/- 1 protein-changing mutations per million base pairs. Therefore, we conducted integrated

  15. Signal and data processing of small targets 1990; Proceedings of the Meeting, Orlando, FL, Apr. 16-18, 1990

    Science.gov (United States)

    Drummond, Oliver E.

    Various papers on signal and data processing of small targets are presented. Individual topics addressed include: clutter rejection using multispectral processing, new sensor for automatic guidance, Doppler domain localized generalized-likelihood-ratio detector, linear filter for resolution of point sources, analysis of order-statistic filters for robust detection, distribution functions for additive Gaussian and gamma noise, temperature discrimination of closely space objects, knowledge-based tracking algorithm, detecting and tracking low-observable targets using IR, weak target detection using the entropy concept, measurement-based neural-net multitarget tracker, object-track closed-form solution in angle space, passive-sensor data association for tracking. Also discussed are: application of MHT to dim moving targets, automatic static covariance analysis with mathematica, neural network implementation of plot/track association, application of Bayesian networks to multitarget tracking, tracking clusters and extended objects with multiple sensors, target tracking by human operator, finite impulse response estimator, multitarget tracking using an extended Kalman filter, maneuvering target tracking using a two-state model algorithm, mixture reduction algorithms for target tracking in clutter, scene interpretation approach to high-level target tracking.

  16. Signal recovery in imaging photoplethysmography

    International Nuclear Information System (INIS)

    Holton, Benjamin D; Mannapperuma, Kavan; Lesniewski, Peter J; Thomas, John C

    2013-01-01

    Imaging photoplethysmography is an emerging technique for the extraction of biometric information from people using video recordings. The focus is on extracting the cardiac heart rate of the subject by analysing the luminance of the colour video signal and identifying periodic components. Advanced signal processing is needed to recover the information required. In this paper, independent component analysis (ICA), principal component analysis, auto- and cross-correlation are investigated and compared with respect to their effectiveness in extracting the relevant information from video recordings. Results obtained are compared with those recorded by a modern commercial finger pulse oximeter. It is found that ICA produces the most consistent results. (paper)

  17. Signal recovery in imaging photoplethysmography.

    Science.gov (United States)

    Holton, Benjamin D; Mannapperuma, Kavan; Lesniewski, Peter J; Thomas, John C

    2013-11-01

    Imaging photoplethysmography is an emerging technique for the extraction of biometric information from people using video recordings. The focus is on extracting the cardiac heart rate of the subject by analysing the luminance of the colour video signal and identifying periodic components. Advanced signal processing is needed to recover the information required. In this paper, independent component analysis (ICA), principal component analysis, auto- and cross-correlation are investigated and compared with respect to their effectiveness in extracting the relevant information from video recordings. Results obtained are compared with those recorded by a modern commercial finger pulse oximeter. It is found that ICA produces the most consistent results.

  18. Hedgehog Signalling is Downregulated in Celiac Disease

    Directory of Open Access Journals (Sweden)

    Rui Liang

    2013-01-01

    Full Text Available BACKGROUND: Celiac disease (CD is a common autoimmune disorder of the small intestine that occurs in genetically predisposed individuals. Animal studies have suggested that the hedgehog (Hh signalling pathway is involved in gut inflammation, injury and repair.

  19. Small RNAs controlling outer membrane porins

    DEFF Research Database (Denmark)

    Valentin-Hansen, Poul; Johansen, Jesper; Rasmussen, Anders A

    2007-01-01

    are key regulators of environmental stress. Recent work has revealed an intimate interplay between small RNA regulation of outer membrane proteins and the stress-induced sigmaE-signalling system, which has an essential role in the maintenance of the integrity of the outer membrane.......Gene regulation by small non-coding RNAs has been recognized as an important post-transcriptional regulatory mechanism for several years. In Gram-negative bacteria such as Escherichia coli and Salmonella, these RNAs control stress response and translation of outer membrane proteins and therefore...

  20. Dynamics of optical signals in a nematic waveguide

    Science.gov (United States)

    Reyes, J. Adrian

    2001-03-01

    We study the modes in a nonlinear nematic waveguide above the Frederickz transition and calculate each of the thresholds associated with different optical and orientational modes. Then, we exhibit the presence of kink-like solutions for the orientational equation under the action of optical fields and study its propagation. Finally, we analyse the dynamics of optical signal in the presence of orientational kinks for different modes and type of signals.

  1. Neurotransmitter signaling in white matter.

    Science.gov (United States)

    Butt, Arthur M; Fern, Robert F; Matute, Carlos

    2014-11-01

    White matter (WM) tracts are bundles of myelinated axons that provide for rapid communication throughout the CNS and integration in grey matter (GM). The main cells in myelinated tracts are oligodendrocytes and astrocytes, with small populations of microglia and oligodendrocyte precursor cells. The prominence of neurotransmitter signaling in WM, which largely exclude neuronal cell bodies, indicates it must have physiological functions other than neuron-to-neuron communication. A surprising aspect is the diversity of neurotransmitter signaling in WM, with evidence for glutamatergic, purinergic (ATP and adenosine), GABAergic, glycinergic, adrenergic, cholinergic, dopaminergic and serotonergic signaling, acting via a wide range of ionotropic and metabotropic receptors. Both axons and glia are potential sources of neurotransmitters and may express the respective receptors. The physiological functions of neurotransmitter signaling in WM are subject to debate, but glutamate and ATP-mediated signaling have been shown to evoke Ca(2+) signals in glia and modulate axonal conduction. Experimental findings support a model of neurotransmitters being released from axons during action potential propagation acting on glial receptors to regulate the homeostatic functions of astrocytes and myelination by oligodendrocytes. Astrocytes also release neurotransmitters, which act on axonal receptors to strengthen action potential propagation, maintaining signaling along potentially long axon tracts. The co-existence of multiple neurotransmitters in WM tracts suggests they may have diverse functions that are important for information processing. Furthermore, the neurotransmitter signaling phenomena described in WM most likely apply to myelinated axons of the cerebral cortex and GM areas, where they are doubtless important for higher cognitive function. © 2014 Wiley Periodicals, Inc.

  2. Signal Propagation Delay as a Barrier to Control Applications in WAN

    DEFF Research Database (Denmark)

    Knudsen, Thomas Phillip; Patel, A.; Pedersen, Jens Myrup

    With the advent in WAN of delay sensitive technical applications, such as remote control, signal propagation delay becomes a major problem. The extent of the problem is analysed by lower bounding the delay in relation to different transmission media. Requirements for reliability and bandwidth are...... are considered. The consequences of this bounding for communication network planning and provisioning are discussed in relation to mitigating the effects of signal propagation delay as a barrier to the penetration of control applications into WAN......With the advent in WAN of delay sensitive technical applications, such as remote control, signal propagation delay becomes a major problem. The extent of the problem is analysed by lower bounding the delay in relation to different transmission media. Requirements for reliability and bandwidth...

  3. A portable, differential amplifier for recording high frequency EEG signals and evoked potentials

    International Nuclear Information System (INIS)

    Donos, Cristian; Giurgiu, Liviu; Popescu, Aurel; Mocanu, Marian

    2010-01-01

    In a clinical context, EEG refers to recording the brain's spontaneous electric activity, using small electrodes placed on the scalp. The signals collected are electric 'potentials' measured between two electrodes. Usually, for a healthy adult, these signals have small voltage (10 μV to 100 μV) and frequencies in the 0-40 Hz range. In the scientific literature, there are mentioned EEG signals and evoked potentials that have higher frequencies (up to 600 Hz) and amplitudes lower than 500 ηV. For this reason, building an amplifier capable of recording EEG signals in the ηV range and with frequencies up to couple of kHz is necessary to continue research beyond 600 Hz. We designed a very low noise amplifier that is able to measure/record EEG signals in the ηV range over a very large frequency bandwidth (0.09 Hz -385 kHz).(Author)

  4. Subliminal stimulation and somatosensory signal detection.

    Science.gov (United States)

    Ferrè, Elisa Raffaella; Sahani, Maneesh; Haggard, Patrick

    2016-10-01

    Only a small fraction of sensory signals is consciously perceived. The brain's perceptual systems may include mechanisms of feedforward inhibition that protect the cortex from subliminal noise, thus reserving cortical capacity and conscious awareness for significant stimuli. Here we provide a new view of these mechanisms based on signal detection theory, and gain control. We demonstrated that subliminal somatosensory stimulation decreased sensitivity for the detection of a subsequent somatosensory input, largely due to increased false alarm rates. By delivering the subliminal somatosensory stimulus and the to-be-detected somatosensory stimulus to different digits of the same hand, we show that this effect spreads across the sensory surface. In addition, subliminal somatosensory stimulation tended to produce an increased probability of responding "yes", whether the somatosensory stimulus was present or not. Our results suggest that subliminal stimuli temporarily reduce input gain, avoiding excessive responses to further small inputs. This gain control may be automatic, and may precede discriminative classification of inputs into signals or noise. Crucially, we found that subliminal inputs influenced false alarm rates only on blocks where the to-be-detected stimuli were present, and not on pre-test control blocks where they were absent. Participants appeared to adjust their perceptual criterion according to a statistical distribution of stimuli in the current context, with the presence of supraliminal stimuli having an important role in the criterion-setting process. These findings clarify the cognitive mechanisms that reserve conscious perception for salient and important signals. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Age-related changes of healthy bone marrow cell signaling in response to growth factors provide insight into low risk MDS.

    Science.gov (United States)

    Kornblau, Steven M; Cohen, Aileen C; Soper, David; Huang, Ying-Wen; Cesano, Alessandra

    2014-11-01

    Single Cell Network Profiling (SCNP) is a multiparametric flow cytometry-based assay that quantifiably and simultaneously measures changes in intracellular signaling proteins in response to in vitro extracellular modulators at the single cell level. Myelodysplastic syndrome (MDS) is a heterogeneous clonal disorder of hematopoietic stem cells that occurs in elderly subjects and is characterized by dysplasia and ineffective hematopoiesis. The functional responsiveness of MDS bone marrow (BM) hematopoietic cells, including functionally distinct myeloid and erythroid precursor subsets, to hematopoietic growth factors (HGF) and the relationship of modulated signaling to disease characteristics is poorly understood. SCNP was used first to examine the effects of age on erythropoietin (EPO) and granulocyte colony stimulating factor (GCSF)-induced signaling in myeloid, nucleated red blood cells (nRBC), and CD34 expressing cell subsets in healthy BM (n = 15). SCNP was then used to map functional signaling profiles in low risk (LR) MDS (n = 7) for comparison to signaling in samples from healthy donors and to probe signaling associations within clinically defined subgroups. In healthy BM samples, signaling responses to HGF were quite homogeneous (i.e., tightly regulated) with age-dependent effects observed in response to EPO but not to GCSF. Despite the relatively small number of samples assayed in the study, LR MDS could be classified into distinct subgroups based on both cell subset frequency and signaling profiles. As a correlate of underlying genetic abnormalities, signal transduction analyses may provide a functional and potentially clinically relevant classification of MDS. Further evaluation in a larger cohort is warranted. © 2013 Clinical Cytometry Society.

  6. Incentives for Truthful Information Elicitation of Continuous Signals

    OpenAIRE

    Radanovic, Goran; Faltings, Boi

    2014-01-01

    We consider settings where a collective intelligence is formed by aggregating information contributed from many independent agents, such as product reviews, community sensing, or opinion polls. We propose a novel mechanism that elicits both private signals and beliefs. The mechanism extends the previous versions of the Bayesian Truth Serum (the original BTS, the RBTS, and the multi-valued BTS), by allowing small populations and non-binary private signals, while not requiring additional assump...

  7. Chemical Modulation of WNT Signaling in Cancer.

    Science.gov (United States)

    Zhang, Li-Shu; Lum, Lawrence

    2018-01-01

    Genetically based observations stemming from defects in development and in regeneration form the foundation of our understanding regarding how the secreted WNT proteins control coordinated cell fate decision-making in adult tissues. At the same time, our anticipation of potential benefits and unwanted toxicities associated with candidate anticancer agents targeting WNT signal transduction are also reliant upon this blueprint of WNT-associated physiology. Despite the long established role of WNT signaling in cancer, the emergence of WNT signaling as a suppressor of immunological attack in melanoma reveals an unanticipated anticancer potential in targeting WNT signaling. Here we review the literature associated with WNT signaling in cancer and discuss potential challenges that may be associated with the chemical attack of this important cellular process in achieving therapeutic goals. Although a number of small molecules targeting WNT signaling are introduced here, we center our discussion on antagonists of the WNT acyltransferase porcupine (PORCN) given the recent entry of two candidate molecules in clinical testing. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. PKD signaling and pancreatitis

    Science.gov (United States)

    Yuan, Jingzhen; Pandol, Stephen J.

    2016-01-01

    Background Acute pancreatitis is a serious medical disorder with no current therapies directed to the molecular pathogenesis of the disorder. Inflammation, inappropriate intracellular activation of digestive enzymes, and parenchymal acinar cell death by necrosis are the critical pathophysiologic processes of acute pancreatitis. Thus, it is necessary to elucidate the key molecular signals that mediate these pathobiologic processes and develop new therapeutic strategies to attenuate the appropriate signaling pathways in order to improve outcomes for this disease. A novel serine/threonine protein kinase D (PKD) family has emerged as key participants in signal transduction, and this family is increasingly being implicated in the regulation of multiple cellular functions and diseases. Methods This review summarizes recent findings of our group and others regarding the signaling pathway and the biological roles of the PKD family in pancreatic acinar cells. In particular, we highlight our studies of the functions of PKD in several key pathobiologic processes associated with acute pancreatitis in experimental models. Results Our findings reveal that PKD signaling is required for NF-κB activation/inflammation, intracellular zymogen activation, and acinar cell necrosis in rodent experimental pancreatitis. Novel small-molecule PKD inhibitors attenuate the severity of pancreatitis in both in vitro and in vivo experimental models. Further, this review emphasizes our latest advances in the therapeutic application of PKD inhibitors to experimental pancreatitis after the initiation of pancreatitis. Conclusions These novel findings suggest that PKD signaling is a necessary modulator in key initiating pathobiologic processes of pancreatitis, and that it constitutes a novel therapeutic target for treatments of this disorder. PMID:26879861

  9. Identification of Hedgehog signaling outcomes in mouse testis development using a hanging drop-culture system.

    Science.gov (United States)

    Szczepny, Anette; Hogarth, Cathryn A; Young, Julia; Loveland, Kate L

    2009-02-01

    The Hedgehog (Hh) signaling pathway affects fetal testis growth. Recently, we described the dynamic cellular production of Hh signaling pathway components in juvenile and adult rodent testes. The Hh signaling is understood to regulate cord formation in the fetal testis, but minimal knowledge exists regarding how Hh signaling impacts the postnatal testis. To investigate this, we employed hanging drop cultures, which are used routinely in embryoid body formation. This approach has the advantage of using small media volume, and we examined its suitability for short-term culture of both murine embryonic gonads and adult testis tubules. The effects of cyclopamine, a specific Hh signaling inhibitor, were examined following culture of Embryonic Day 11.5 urogenital ridges (as control) and adult seminiferous tubule fragments for 24-48 h using histological, cell proliferation, and gene expression analyses. Cultured embryonic testes displayed generally normal cord structure, anti-Müllerian hormone (Amh) expression, and cell proliferation; known Hh target gene expression (Gli1, osteopontin, official symbol Spp1, and Amh) was altered in response to cyclopamine. Cultured adult tubules exhibited some loss of seminiferous epithelium organization over 48 h. Spermatogonia continued to proliferate, however, and no significant loss of viability was noted overall. Addition of cyclopamine significantly affected levels of Gli1, Igfbp6, Ccnd2 (cyclin D2), Ccnb1 (cyclin B1), Spp1, Kit, and Amh mRNAs; these genes have been shown previously to be expressed in Sertoli and germ cells. These novel results identify Hh target genes in the testis and demonstrate this signaling pathway likely affects cell survival and differentiation in the context of normal adult testis.

  10. Alternative signaling pathways as potential therapeutic targets for overcoming EGFR and c-Met inhibitor resistance in non-small cell lung cancer.

    Directory of Open Access Journals (Sweden)

    Jason T Fong

    Full Text Available The use of tyrosine kinase inhibitors (TKIs against EGFR/c-Met in non-small cell lung cancer (NSCLC has been shown to be effective in increasing patient progression free survival (PFS, but their efficacy is limited due to the development of resistance and tumor recurrence. Therefore, understanding the molecular mechanisms underlying development of drug resistance in NSCLC is necessary for developing novel and effective therapeutic approaches to improve patient outcome. This study aims to understand the mechanism of EGFR/c-Met tyrosine kinase inhibitor (TKI resistance in NSCLC. H2170 and H358 cell lines were made resistant to SU11274, a c-Met inhibitor, and erlotinib, an EGFR inhibitor, through step-wise increases in TKI exposure. The IC50 concentrations of resistant lines exhibited a 4-5 and 11-22-fold increase for SU11274 and erlotinib, respectively, when compared to parental lines. Furthermore, mTOR and Wnt signaling was studied in both cell lines to determine their roles in mediating TKI resistance. We observed a 2-4-fold upregulation of mTOR signaling proteins and a 2- to 8-fold upregulation of Wnt signaling proteins in H2170 erlotinib and SU11274 resistant cells. H2170 and H358 cells were further treated with the mTOR inhibitor everolimus and the Wnt inhibitor XAV939. H358 resistant cells were inhibited by 95% by a triple combination of everolimus, erlotinib and SU11274 in comparison to 34% by a double combination of these drugs. Parental H2170 cells displayed no sensitivity to XAV939, while resistant cells were significantly inhibited (39% by XAV939 as a single agent, as well as in combination with SU11274 and erlotinib. Similar results were obtained with H358 resistant cells. This study suggests a novel molecular mechanism of drug resistance in lung cancer.

  11. Spectral responses of gravel beaches to tidal signals

    Science.gov (United States)

    Geng, Xiaolong; Boufadel, Michel C.

    2017-01-01

    Tides have been recognized as a major driving forcing affecting coastal aquifer system, and deterministic modeling has been very effective in elucidating mechanisms caused by tides. However, such modeling does not lend itself to capture embedded information in the signal, and rather focuses on the primary processes. Here, using yearlong data sets measured at beaches in Alaska Prince William Sound, we performed spectral and correlation analyses to identify temporal behavior of pore-water pressure, temperature and salinity. We found that the response of the beach system was characterized by fluctuations of embedded diurnal, semidiurnal, terdiurnal and quarterdiurnal tidal components. Hydrodynamic dispersion of salinity and temperature, and the thermal conductivity greatly affected pore water signals. Spectral analyses revealed a faster dissipation of the semi-diurnal component with respect to the diurnal components. Correlation functions showed that salinity had a relatively short memory of the tidal signal when inland freshwater recharge was large. In contrast, the signature of the tidal signal on pore-water temperature persisted for longer times, up to a week. We also found that heterogeneity greatly affected beach response. The response varied from a simple linear mapping in the frequency domain to complete modulation and masking of the input frequencies.

  12. Recent advances in the discovery of small molecule c-Met Kinase inhibitors.

    Science.gov (United States)

    Parikh, Palak K; Ghate, Manjunath D

    2018-01-01

    c-Met is a prototype member of a subfamily of heterodimeric receptor tyrosine kinases (RTKs) and is the receptor for hepatocyte growth factor (HGF). Binding of HGF to its receptor c-Met, initiates a wide range of cellular signalling, including those involved in proliferation, motility, migration and invasion. Importantly, dysregulated HGF/c-Met signalling is a driving factor for numerous malignancies and promotes tumour growth, invasion, dissemination and/or angiogenesis. Dysregulated HGF/c-Met signalling has also been associated with poor clinical outcomes and resistance acquisition to some approved targeted therapies. Thus, c-Met kinase has emerged as a promising target for cancer drug development. Different therapeutic approaches targeting the HGF/c-Met signalling pathway are under development for targeted cancer therapy, among which small molecule inhibitors of c-Met kinase constitute the largest effort within the pharmaceutical industry. The review is an effort to summarize recent advancements in medicinal chemistry development of small molecule c-Met kinase inhibitors as potential anti-cancer agents which would certainly help future researchers to bring further developments in the discovery of small molecule c-Met kinase inhibitors. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. In roots of Arabidopsis thaliana, the damage-associated molecular pattern AtPep1 is a stronger elicitor of immune signalling than flg22 or the chitin heptamer.

    Directory of Open Access Journals (Sweden)

    Lorenzo Poncini

    Full Text Available Plants interpret their immediate environment through perception of small molecules. Microbe-associated molecular patterns (MAMPs such as flagellin and chitin are likely to be more abundant in the rhizosphere than plant-derived damage-associated molecular patterns (DAMPs. We investigated how the Arabidopsis thaliana root interprets MAMPs and DAMPs as danger signals. We monitored root development during exposure to increasing concentrations of the MAMPs flg22 and the chitin heptamer as well as of the DAMP AtPep1. The tissue-specific expression of defence-related genes in roots was analysed using a toolkit of promoter::YFPN lines reporting jasmonic acid (JA-, salicylic acid (SA-, ethylene (ET- and reactive oxygen species (ROS- dependent signalling. Finally, marker responses were analysed during invasion by the root pathogen Fusarium oxysporum. The DAMP AtPep1 triggered a stronger activation of the defence markers compared to flg22 and the chitin heptamer. In contrast to the tested MAMPs, AtPep1 induced SA- and JA-signalling markers in the root and caused a severe inhibition of root growth. Fungal attack resulted in a strong activation of defence genes in tissues close to the invading fungal hyphae. The results collectively suggest that AtPep1 presents a stronger danger signal to the Arabidopsis root than the MAMPs flg22 and chitin heptamer.

  14. A two-channel wave analyser for sounding rockets and satellites

    International Nuclear Information System (INIS)

    Brondz, E.

    1989-04-01

    Studies of low frequency electromagnetic waves, produced originally by lightning discharges penetrating the ionosphere, provide an important source of valuable information about the earth's surrounding plasma. Use of rockets and satellites supported by ground-based observations implies, unique opportunity for measuring in situ a number of parameters simultaneously in order to correlate data from various measurements. However, every rocket experiment has to be designed bearing in mind telemetry limitations and/or short flight duration. Typical flight duration for Norwegian rockets launched from Andoeya Rocket Range is 500 to 600 s. Therefore, the most desired way to use a rocket or satellite is to carry out data analyses on board in real time. Recent achievements in Digital Signal Processing (DSP) technology have made it possible to undertake very complex on board data manipulation. As a part of rocket instrumentation, a DSP based unit able to carry out on board analyses of low frequency electromagnetic waves in the ionosphere has been designed. The unit can be seen as a general purpose computer built on the basis of a fixed-point 16 bit signal processor. The unit is supplied with a program code in order to perform wave analyses on two independent channels simultaneously. The analyser is able to perform 256 point complex fast fourier transformations, and it produce a spectral power desity estimate on both channels every 85 ms. The design and construction of the DSP based unit is described and results from the tests are presented

  15. Social signal processing for studying parent-infant interaction

    Directory of Open Access Journals (Sweden)

    Marie eAvril

    2014-12-01

    Full Text Available Studying early interactions is a core issue of infant development and psychopathology. Automatic social signal processing theoretically offers the possibility to extract and analyse communication by taking an integrative perspective, considering the multimodal nature and dynamics of behaviours (including synchrony. This paper proposes an explorative method to acquire and extract relevant social signals from a naturalistic early parent-infant interaction. An experimental setup is proposed based on both clinical and technical requirements. We extracted various cues from body postures and speech productions of partners using the IMI2S (Interaction, Multimodal Integration, and Social Signal Framework. Preliminary clinical and computational results are reported for two dyads (one pathological in a situation of severe emotional neglect and one normal control as an illustration of our cross-disciplinary protocol. The results from both clinical and computational analyses highlight similar differences: the pathological dyad shows dyssynchronic interaction led by the infant whereas the control dyad shows synchronic interaction and a smooth interactive dialog. The results suggest that the current method might be promising for future studies.

  16. Tyrosine Phosphorylation in Toll-Like Receptor Signaling

    Science.gov (United States)

    Chattopadhyay, Saurabh; Sen, Ganes C.

    2014-01-01

    There is a wealth of knowledge about how different Ser/Thr protein kinases participate in Toll-like receptor (TLR) signaling. In many cases, we know the identities of the Ser/Thr residues of various components of the TLR-signaling pathways that are phosphorylated, the functional consequences of the phosphorylation and the responsible protein kinases. In contrast, the analysis of Tyr-phosphorylation of TLRs and their signaling proteins is currently incomplete, because several existing analyses are not systematic or they do not rely on robust experimental data. Nevertheless, it is clear that many TLRs require, for signaling, ligand-dependent phosphorylation of specific Tyr residues in their cytoplasmic domains; the list includes TLR2, TLR3, TLR4, TLR5, TLR8 and TLR9. In this article, we discuss the current status of knowledge on the effect of Tyr-phosphorylation of TLRs and their signaling proteins on their biochemical and biological functions, the possible identities of the relevant protein tyrosine kinases (PTKs) and the nature of regulations of PTK-mediated activation of TLR signaling pathways. PMID:25022196

  17. Small angle scattering of X radiation and slow neutrons in structural analyses of amorphous solids

    International Nuclear Information System (INIS)

    Kostorz, G.

    1980-01-01

    Small angle scattering of x radiation and slow neutrons allows to detect inhomogeneities of the dimension of ten to some thousands of Angstroem by the difference in the scattering length density. The progress made during recent years in the development of apparatusses has created the possibility of solving very complicated problems. A first outline shows that in separation processes as well as in investigating extended defects the method of small angle scattering may provide valuable contributions to the analysis of the non-crystalline state

  18. Enhancement of crack detection in stud bolts of nuclear reactor by ultrasonic signal processing technique

    International Nuclear Information System (INIS)

    Lee, J.H.; Oh, W.D.; Choi, S.W.; Park, M.H.

    2004-01-01

    'Full-text:' The stud bolts is one of the most critical parts for safety of reactor vessels in the nuclear power plants. However, in the application of ultrasonic technique for crack detection in stud bolt, some difficulties encountered are classification of crack signal from the signals reflected from threads part in stud bolt. In this study, shadow effect technique combined with new signal processing method is Investigated to enhance the detectability of small crack initiated from root of thread in stud bolt. The key idea of signal processing is based on the fact that the shape of waveforms from the threads is uniform since the shape of the threads in a bolt is same. If some cracks exist in the thread, the flaw signals are different to the reference signals. It is demonstrated that the small flaws are efficiently detected by novel ultrasonic technique combined with this new signal processing concept. (author)

  19. Entropy Analyses of Droplet Combustion in Convective Environment with Small Reynolds Number

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaobin; ZHANG Wei; ZHANG Xuejun

    2013-01-01

    This paper analyzes the entropy generation rate of simple pure droplet combustion in a temperature-elevated air convective environment based on the solutions of flow,and heat and mass transfer between the two phases.The flow-field calculations are carried out by solving the respective conservation equations for each phase,accounting for the droplet deformation with the axisymmetric model.The effects of the temperature,velocity and oxygen fraction of the free stream air on the total entropy generation rate in the process of the droplet combustion are investigated.Special attention is given to analyze the quantitative effects of droplet deformation.The results reveal that the entropy generation rate due to chemical reaction occupies a large fraction of the total entropy generated,as a result of the large areas covered by the flame.Although,the magnitude of the entropy generation rate per volume due to heat transfer and combined mass and heat transfer has a magnitude of one order greater than that due to chemical reaction,they cover a very limited area,leading to a small fraction of the total entropy generated.The entropy generation rate due to mass transfer is negligible.High temperature and high velocity of the free stream are advantageous to increase the exergy efficiency in the range of small Reynolds number (<1) from the viewpoint of the second-law analysis over the droplet lifetime.The effect of droplet deformation on the total entropy generation is the modest.

  20. ARE SMALL-FIRM CLUSTERS EMERGENT PHENOMENA? EVIDENCE FROM ZIMBABWE’S SMALL FURNITURE- MANUFACTURING FIRMS

    Directory of Open Access Journals (Sweden)

    Godfrey MUPONDA

    2014-07-01

    Full Text Available The purpose of this study was to explore the reasons behind the rapid growth and apparent dynamism of Zimbabwe’s small-firm industrial clusters. The hypothesis behind the study was that these small-firm clusters are emergent phenomena. The study analysed the capital utilisation techniques of small firms located in a large industrial cluster in order to determine the factors that lead to the collective efficiency of such firms. The study found that, in comparison with large, stock exchange-listed firms, the cluster environment enables the small firm to operate from a relatively small capital base and also to use its capital more efficiently in creating revenues and profits. The individual firm does not have to invest its capital in a large assets base as this is done by a specialised group of firms within the cluster. Thus, the cluster has the characteristics of an emergent phenomenon.

  1. Severe small bowel radiation enteritis

    International Nuclear Information System (INIS)

    Jaen, J.; Santos, J.A.; Carrion, J.R.; Garcia, P.

    1989-01-01

    We have during recent years observed 8 patients with serious radiation injury to the small intestine. As the cases are quite illustrative, their symptomatology is briefly reported and the treatment and possible predisposing factors are analysed. (orig./MG)

  2. Inhibitory neurons modulate spontaneous signaling in cultured cortical neurons: density-dependent regulation of excitatory neuronal signaling

    International Nuclear Information System (INIS)

    Serra, Michael; Guaraldi, Mary; Shea, Thomas B

    2010-01-01

    Cortical neuronal activity depends on a balance between excitatory and inhibitory influences. Culturing of neurons on multi-electrode arrays (MEAs) has provided insight into the development and maintenance of neuronal networks. Herein, we seeded MEAs with murine embryonic cortical/hippocampal neurons at different densities ( 1000 cells mm −2 ) and monitored resultant spontaneous signaling. Sparsely seeded cultures displayed a large number of bipolar, rapid, high-amplitude individual signals with no apparent temporal regularity. By contrast, densely seeded cultures instead displayed clusters of signals at regular intervals. These patterns were observed even within thinner and thicker areas of the same culture. GABAergic neurons (25% of total neurons in our cultures) mediated the differential signal patterns observed above, since addition of the inhibitory antagonist bicuculline to dense cultures and hippocampal slice cultures induced the signal pattern characteristic of sparse cultures. Sparsely seeded cultures likely lacked sufficient inhibitory neurons to modulate excitatory activity. Differential seeding of MEAs can provide a unique model for analyses of pertubation in the interaction between excitatory and inhibitory function during aging and neuropathological conditions where dysregulation of GABAergic neurons is a significant component

  3. About the identification of signals at LHC

    CERN Document Server

    Mansoulié, Bruno

    2015-01-01

    This chapter describes the main ingredients and steps of the analysis used in the search for the Standard Model Higgs boson decaying into WW (l‎, l‎, νν‎) in the ATLAS experiment. It presents a short guide through a “modern” analysis, typical of the analyses performed on LHC data. The main ingredients are reviewed: irreducible and reducible backgrounds, background estimates from Monte Carlo or data-driven, signal and control regions, global fit, extraction of limits and signal, and the look-elsewhere effect.

  4. Signal modulation as a mechanism for handicap disposal

    Science.gov (United States)

    Gavassa, Sat; Silva, Ana C.; Gonzalez, Emmanuel; Stoddard, Philip K.

    2012-01-01

    Signal honesty may be compromised when heightened competition provides incentive for signal exaggeration. Some degree of honesty might be maintained by intrinsic handicap costs on signalling or through imposition of extrinsic costs, such as social punishment of low quality cheaters. Thus, theory predicts a delicate balance between signal enhancement and signal reliability that varies with degree of social competition, handicap cost, and social cost. We investigated whether male sexual signals of the electric fish Brachyhypopomus gauderio would become less reliable predictors of body length when competition provides incentives for males to boost electric signal amplitude. As expected, social competition under natural field conditions and in controlled lab experiments drove males to enhance their signals. However, signal enhancement improved the reliability of the information conveyed by the signal, as revealed in the tightening of the relationship between signal amplitude and body length. Signal augmentation in male B. gauderio was independent of body length, and thus appeared not to be curtailed through punishment of low quality (small) individuals. Rather, all individuals boosted their signals under high competition, but those whose signals were farthest from the predicted value under low competition boosted signal amplitude the most. By elimination, intrinsic handicap cost of signal production, rather than extrinsic social cost, appears to be the basis for the unexpected reinforcement of electric signal honesty under social competition. Signal modulation may provide its greatest advantage to the signaller as a mechanism for handicap disposal under low competition rather than as a mechanism for exaggeration of quality under high competition. PMID:22665940

  5. Chemical intervention in plant sugar signalling increases yield and resilience

    Science.gov (United States)

    Griffiths, Cara A.; Sagar, Ram; Geng, Yiqun; Primavesi, Lucia F.; Patel, Mitul K.; Passarelli, Melissa K.; Gilmore, Ian S.; Steven, Rory T.; Bunch, Josephine; Paul, Matthew J.; Davis, Benjamin G.

    2016-12-01

    The pressing global issue of food insecurity due to population growth, diminishing land and variable climate can only be addressed in agriculture by improving both maximum crop yield potential and resilience. Genetic modification is one potential solution, but has yet to achieve worldwide acceptance, particularly for crops such as wheat. Trehalose-6-phosphate (T6P), a central sugar signal in plants, regulates sucrose use and allocation, underpinning crop growth and development. Here we show that application of a chemical intervention strategy directly modulates T6P levels in planta. Plant-permeable analogues of T6P were designed and constructed based on a ‘signalling-precursor’ concept for permeability, ready uptake and sunlight-triggered release of T6P in planta. We show that chemical intervention in a potent sugar signal increases grain yield, whereas application to vegetative tissue improves recovery and resurrection from drought. This technology offers a means to combine increases in yield with crop stress resilience. Given the generality of the T6P pathway in plants and other small-molecule signals in biology, these studies suggest that suitable synthetic exogenous small-molecule signal precursors can be used to directly enhance plant performance and perhaps other organism function.

  6. Global multi-decadal ocean climate and small-pelagic fish population

    International Nuclear Information System (INIS)

    Tourre, Yves M; Lluch-Cota, Salvador E; White, Warren B

    2007-01-01

    Ocean climate, environmental and biological conditions vary on several spatio-temporal scales. Besides climate change associated with anthropogenic activity, there is growing evidence of a natural global multi-decadal climate signal in the ocean-atmosphere-biosphere climate system. The spatio-temporal evolution of this signal is thus analyzed during the 20th century and compared to the variability of small-pelagic fish landings. It is argued that the low-frequency global ocean environment and plankton ecosystems must be modified such that small-pelagic populations vary accordingly. A small-pelagic global index or fishing 'regime indicator series' (RIS) (i.e. a small-pelagic abundance indicator) is used. RIS is derived from fish landings data in the four main fishing areas in the Pacific and Atlantic oceans. Global RIS changes phase (from positive to negative values) when SST multi-decadal anomalies are out-of-phase between the eastern Pacific and southern Atlantic. RIS also displays maxima during the mid-30s to early-40s and the late-70s to early-80s when the multi-decadal signal was approximately changing phases (Tourre and White 2006 Geophys. Res. Lett. 33 L06716). It is recognized that other factors may modulate fish stocks, including anthropogenic predation. Nevertheless it is proposed that variable climate and environment, and the low-frequency 'global synchrony' of small-pelagic landings (Schwartzlose et al 1999 S. Afr. J. Mar. Sci. 21 289-347), could be associated with the multi-decadal changes in global ocean climate conditions

  7. Load Characterization for small domestic appliances and electronics

    NARCIS (Netherlands)

    Van der Sluis, P.

    2009-01-01

    In this report, the energy consumption of small domestic loads has been analysed. To make the around 100 types of appliances considereda bit manageable, the appliances were categorized into several groups. The possibilities for time-shifting of the energy use of these small appliances was

  8. Method of test signal design for estimating the aircraft aerodynamic parameters

    Science.gov (United States)

    Belokon', S. A.; Zolotukhin, Yu. N.; Filippov, M. N.

    2017-07-01

    A method of test signal design is proposed for studying the aircraft aerodynamic characteristics with the use of the technology of dynamically scaled free-flight models. Simultaneous excitation of all input channels in a prescribed frequency band by a set of mutually orthogonal signals is applied to increase the efficiency. A modified method of calculating the set of mutually orthogonal sinusoidal signals with a small normalized peak factor is presented. Results of simulating the aircraft motion in the MATLAB/Simulink environment with the use of the developed method of test signal design are reported.

  9. Small scale smugglers in Tamaulipas, Mexico

    Directory of Open Access Journals (Sweden)

    Simón Pedro Izcara Palacios

    2013-07-01

    Full Text Available Small-scale part-time smugglers are embedded in the migrant community itself. They work in the United States for several months before returning to their place of origin to organize, with the help of several assistants, a small group of migrants, who are transported where the coyotes themselves are going. This article analyses small-scale smuggling carried out by Tamaulipas' polleros, who transport to the United States, one or a few times per year, migrants from their hometowns or other neighboring areas in order to be employed in the farming sector.

  10. Do small fish mean no voucher? Using a flatbed desktop scanner to document larval and small specimens before destructive analyses

    Czech Academy of Sciences Publication Activity Database

    Kalous, L.; Šlechtová, Věra; Petrtýl, M.; Kohout, Jan; Čech, Martin

    2010-01-01

    Roč. 26, č. 4 (2010), s. 614-617 ISSN 0175-8659 R&D Projects: GA ČR GA206/06/1371; GA ČR GP206/09/P266 Institutional research plan: CEZ:AV0Z50450515; CEZ:AV0Z60170517 Keywords : small fish * voucher * desktop scanner Subject RIV: GL - Fishing Impact factor: 0.945, year: 2010

  11. Channel Capacity Calculation at Large SNR and Small Dispersion within Path-Integral Approach

    Science.gov (United States)

    Reznichenko, A. V.; Terekhov, I. S.

    2018-04-01

    We consider the optical fiber channel modelled by the nonlinear Shrödinger equation with additive white Gaussian noise. Using Feynman path-integral approach for the model with small dispersion we find the first nonzero corrections to the conditional probability density function and the channel capacity estimations at large signal-to-noise ratio. We demonstrate that the correction to the channel capacity in small dimensionless dispersion parameter is quadratic and positive therefore increasing the earlier calculated capacity for a nondispersive nonlinear optical fiber channel in the intermediate power region. Also for small dispersion case we find the analytical expressions for simple correlators of the output signals in our noisy channel.

  12. Automatic recognition of smoke-plume signatures in lidar signal

    Science.gov (United States)

    Utkin, Andrei B.; Lavrov, Alexander; Vilar, Rui

    2008-10-01

    A simple and robust algorithm for lidar-signal classification based on the fast extraction of sufficiently pronounced peaks and their recognition with a perceptron, whose efficiency is enhanced by a fast nonlinear preprocessing that increases the signal dimension, is reported. The method allows smoke-plume recognition with an error rate as small as 0.31% (19 misdetections and 4 false alarms in analyzing a test set of 7409 peaks).

  13. Analyses of karyotypes and comparative physical locations of the ...

    African Journals Online (AJOL)

    The frequencies of signal detection of the marker, RG556 and the BAC clone, 44B4, were 8.0 and 41.3% in O. sativa, while 9.0 and 42.3% in O. officinalis, respectively. Based on a comparative RFLP map of a wild rice, O. officinalis and O. sativa, comparative analyses of karyotypes of O. officinalis were demonstrated firstly ...

  14. Design and Test of a Signal Packet Router Prototype for the ATLAS NSW sTGC Detector

    CERN Document Server

    Hu, Xueye; The ATLAS collaboration

    2016-01-01

    Abstract– The New Small Wheel (NSW) small-strip thin-gap chambers (sTGC) detector will be installed in Large Hadron Collider (LHC) during ATLAS Phase-I upgrade. For sTGC detector, it requires very high-speed electronic triggering of signal events. On detecting a signal peak, sTGC front-end trigger logic will send out serialized track information on twinax fast serial copper wires to the signal packet Router on the periphery of the new small wheel. The signal packet Router boards handle all incoming traffic from the TDS chips (4.8 Gbps), serving as a very fast switching-yard between incoming active TDS signals and a limited number of optoelectronic outputs. There are several design requirements on router: radiation-hard (9kRad), high-speed serial link and low fixed latency in FPGA (field-programmable gate array) data processing. To meet those requirements, a router prototype has been developed for demonstration purpose. The components used in router prototype have been tested in radiation environment to m...

  15. Delineation of the Exact Transcription Termination Signal for Type 3 Polymerase III

    Directory of Open Access Journals (Sweden)

    Zongliang Gao

    2018-03-01

    Full Text Available Type 3 Pol III promoters such as U6 are widely used for expression of small RNAs, including short hairpin RNA for RNAi applications and guide RNA in CRISPR genome-editing platforms. RNA polymerase III uses a T-stretch as termination signal, but the exact properties have not been thoroughly investigated. Here, we systematically measured the in vivo termination efficiency and the actual site of termination for different T-stretch signals in three commonly used human Pol III promoters (U6, 7SK, and H1. Both the termination efficiency and the actual termination site depend on the T-stretch signal. The T4 signal acts as minimal terminator, but full termination efficiency is reached only with a T-stretch of ≥6. The termination site within the T-stretch is quite heterogeneous, and consequently small RNAs have a variable U-tail of 1–6 nucleotides. We further report that such variable U-tails can have a significant negative effect on the functionality of the crRNA effector of the CRISPR-AsCpf1 system. We next improved these crRNAs by insertion of the HDV ribozyme to avoid U-tails. This study provides detailed design guidelines for small RNA expression cassettes based on Pol III.

  16. Identification of Hedgehog Signaling Outcomes in Mouse Testis Development Using a Hanging Drop-Culture System1

    Science.gov (United States)

    Szczepny, Anette; Hogarth, Cathryn A.; Young, Julia; Loveland, Kate L.

    2008-01-01

    The Hedgehog (Hh) signaling pathway affects fetal testis growth. Recently, we described the dynamic cellular production of Hh signaling pathway components in juvenile and adult rodent testes. The Hh signaling is understood to regulate cord formation in the fetal testis, but minimal knowledge exists regarding how Hh signaling impacts the postnatal testis. To investigate this, we employed hanging drop cultures, which are used routinely in embryoid body formation. This approach has the advantage of using small media volume, and we examined its suitability for short-term culture of both murine embryonic gonads and adult testis tubules. The effects of cyclopamine, a specific Hh signaling inhibitor, were examined following culture of Embryonic Day 11.5 urogenital ridges (as control) and adult seminiferous tubule fragments for 24–48 h using histological, cell proliferation, and gene expression analyses. Cultured embryonic testes displayed generally normal cord structure, anti-Müllerian hormone (Amh) expression, and cell proliferation; known Hh target gene expression (Gli1, osteopontin, official symbol Spp1, and Amh) was altered in response to cyclopamine. Cultured adult tubules exhibited some loss of seminiferous epithelium organization over 48 h. Spermatogonia continued to proliferate, however, and no significant loss of viability was noted overall. Addition of cyclopamine significantly affected levels of Gli1, Igfbp6, Ccnd2 (cyclin D2), Ccnb1 (cyclin B1), Spp1, Kit, and Amh mRNAs; these genes have been shown previously to be expressed in Sertoli and germ cells. These novel results identify Hh target genes in the testis and demonstrate this signaling pathway likely affects cell survival and differentiation in the context of normal adult testis. PMID:18843087

  17. Morphoproteomic profiling of the mammalian target of rapamycin (mTOR) signaling pathway in desmoplastic small round cell tumor (EWS/WT1), Ewing's sarcoma (EWS/FLI1) and Wilms' tumor(WT1).

    Science.gov (United States)

    Subbiah, Vivek; Brown, Robert E; Jiang, Yunyun; Buryanek, Jamie; Hayes-Jordan, Andrea; Kurzrock, Razelle; Anderson, Pete M

    2013-01-01

    Desmoplastic small round cell tumor (DSRCT) is a rare sarcoma in adolescents and young adults. The hallmark of this disease is a EWS-WT1 translocation resulting from apposition of the Ewing's sarcoma (EWS) gene with the Wilms' tumor (WT1) gene. We performed morphoproteomic profiling of DSRCT (EWS-WT1), Ewing's sarcoma (EWS-FLI1) and Wilms' tumor (WT1) to better understand the signaling pathways for selecting future targeted therapies. This pilot study assessed patients with DSRCT, Wilms' tumor and Ewing's sarcoma. Morphoproteomics and immunohistochemical probes were applied to detect: p-mTOR (Ser2448); p-Akt (Ser473); p-ERK1/2 (Thr202/Tyr204); p-STAT3 (Tyr 705); and cell cycle-related analytes along with their negative controls. In DSRCT the PI3K/Akt/mTOR pathway is constitutively activated by p-Akt (Ser 473) expression in the nuclear compartment of the tumor cells and p-mTOR phosphorylated on Ser 2448, suggesting mTORC2 (rictor+mTOR) as the dominant form. Ewing's sarcoma had upregulated p-Akt and p-mTOR, predominantly mTORC2. In Wilm's tumor, the mTOR pathway is also activated with most tumor cells moderately expressing p-mTOR (Ser 2448) in plasmalemmal and cytoplasmic compartments. This coincides with the constitutive activation of one of the downstream effectors of the mTORC1 signaling pathway, namely p-p70S6K (Thr 389). There was constitutive activation of the Ras/Raf/ERK pathway p-ERK 1/2 (Thr202/Tyr204) expression in the Wilms tumor and metastatic Ewing's sarcoma, but not in the DSRCT. MORPHOPROTEOMIC TUMOR ANALYSES REVEALED CONSTITUTIVE ACTIVATION OF THE MTOR PATHWAY AS EVIDENCED BY: (a) expression of phosphorylated (p)-mTOR, p-p70S6K; (b) mTORC 2 in EWS and DSRCT; (c) ERK signaling was seen in the advanced setting indicating these as resistance pathways to IGF1R related therapies. This is the first morphoproteomic study of such pathways in these rare malignancies and may have potential therapeutic implications. Further study using morphoproteomic

  18. Grey literature in meta-analyses.

    Science.gov (United States)

    Conn, Vicki S; Valentine, Jeffrey C; Cooper, Harris M; Rantz, Marilyn J

    2003-01-01

    In meta-analysis, researchers combine the results of individual studies to arrive at cumulative conclusions. Meta-analysts sometimes include "grey literature" in their evidential base, which includes unpublished studies and studies published outside widely available journals. Because grey literature is a source of data that might not employ peer review, critics have questioned the validity of its data and the results of meta-analyses that include it. To examine evidence regarding whether grey literature should be included in meta-analyses and strategies to manage grey literature in quantitative synthesis. This article reviews evidence on whether the results of studies published in peer-reviewed journals are representative of results from broader samplings of research on a topic as a rationale for inclusion of grey literature. Strategies to enhance access to grey literature are addressed. The most consistent and robust difference between published and grey literature is that published research is more likely to contain results that are statistically significant. Effect size estimates of published research are about one-third larger than those of unpublished studies. Unfunded and small sample studies are less likely to be published. Yet, importantly, methodological rigor does not differ between published and grey literature. Meta-analyses that exclude grey literature likely (a) over-represent studies with statistically significant findings, (b) inflate effect size estimates, and (c) provide less precise effect size estimates than meta-analyses including grey literature. Meta-analyses should include grey literature to fully reflect the existing evidential base and should assess the impact of methodological variations through moderator analysis.

  19. MRI signal intensity as a maker of impairment in incomplete cervical spinal cord injuries

    International Nuclear Information System (INIS)

    Chiba, Hidefumi; Aoki, Haruhito; Hamabe, Masaki; Sasao, Yutaka; Miura, Takehiko

    1998-01-01

    Incomplete cervical spinal cord injuries such as central cord syndrome may result in prolonged spasticity of the limbs, especially disabilities of the upper extremities, even if the patient is able to walk. In this study, relationship between cord impairment and clinical outcome was investigated using MRI. Results showed that small foci of low signal intensity in T 1 -weighted imaging combined with foci of high signal intensity in T 2 -weighted imaging in follow-up MRI are closely related to the severity of sequelae. Small foci of low signal intensity in T 1 -weighted imaging are considered in the literature to indicate myelomalacia or cyst formation with gliosis. (author)

  20. Analyses of MHD instabilities

    International Nuclear Information System (INIS)

    Takeda, Tatsuoki

    1985-01-01

    In this article analyses of the MHD stabilities which govern the global behavior of a fusion plasma are described from the viewpoint of the numerical computation. First, we describe the high accuracy calculation of the MHD equilibrium and then the analysis of the linear MHD instability. The former is the basis of the stability analysis and the latter is closely related to the limiting beta value which is a very important theoretical issue of the tokamak research. To attain a stable tokamak plasma with good confinement property it is necessary to control or suppress disruptive instabilities. We, next, describe the nonlinear MHD instabilities which relate with the disruption phenomena. Lastly, we describe vectorization of the MHD codes. The above MHD codes for fusion plasma analyses are relatively simple though very time-consuming and parts of the codes which need a lot of CPU time concentrate on a small portion of the codes, moreover, the codes are usually used by the developers of the codes themselves, which make it comparatively easy to attain a high performance ratio on the vector processor. (author)

  1. On understanding crosstalk in the face of small, quantized, signals highly smeared by Poisson statistics

    International Nuclear Information System (INIS)

    Lincoln, D.; Hsieh, F.; Li, H.

    1995-01-01

    As detectors become smaller and more densely packed, signals become smaller and crosstalk between adjacent channels generally increases. Since it is often appropriate to use the distribution of signals in adjacent channels to make a useful measurement, it is imperative that inter-channel crosstalk be well understood. In this paper we shall describe the manner in which Poissonian fluctuations can give counter-intuitive results and offer some methods for extracting the desired information from the highly smeared, observed distributions. (orig.)

  2. Inhibitor of PI3K/Akt Signaling Pathway Small Molecule Promotes Motor Neuron Differentiation of Human Endometrial Stem Cells Cultured on Electrospun Biocomposite Polycaprolactone/Collagen Scaffolds.

    Science.gov (United States)

    Ebrahimi-Barough, Somayeh; Hoveizi, Elham; Yazdankhah, Meysam; Ai, Jafar; Khakbiz, Mehrdad; Faghihi, Faezeh; Tajerian, Roksana; Bayat, Neda

    2017-05-01

    Small molecules as useful chemical tools can affect cell differentiation and even change cell fate. It is demonstrated that LY294002, a small molecule inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway, can inhibit proliferation and promote neuronal differentiation of mesenchymal stem cells (MSCs). The purpose of this study was to investigate the differentiation effect of Ly294002 small molecule on the human endometrial stem cells (hEnSCs) into motor neuron-like cells on polycaprolactone (PCL)/collagen scaffolds. hEnSCs were cultured in a neurogenic inductive medium containing 1 μM LY294002 on the surface of PCL/collagen electrospun fibrous scaffolds. Cell attachment and viability of cells on scaffolds were characterized by scanning electron microscope (SEM) and 3-(4,5-dimethylthiazoyl-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The expression of neuron-specific markers was assayed by real-time PCR and immunocytochemistry analysis after 15 days post induction. Results showed that attachment and differentiation of hEnSCs into motor neuron-like cells on the scaffolds with Ly294002 small molecule were higher than that of the cells on tissue culture plates as control group. In conclusion, PCL/collagen electrospun scaffolds with Ly294002 have potential for being used in neural tissue engineering because of its bioactive and three-dimensional structure which enhances viability and differentiation of hEnSCs into neurons through inhibition of the PI3K/Akt pathway. Thus, manipulation of this pathway by small molecules can enhance neural differentiation.

  3. Accounting for rate variation among lineages in comparative demographic analyses

    Science.gov (United States)

    Hope, Andrew G.; Ho, Simon Y. W.; Malaney, Jason L.; Cook, Joseph A.; Talbot, Sandra L.

    2014-01-01

    Genetic analyses of contemporary populations can be used to estimate the demographic histories of species within an ecological community. Comparison of these demographic histories can shed light on community responses to past climatic events. However, species experience different rates of molecular evolution, and this presents a major obstacle to comparative demographic analyses. We address this problem by using a Bayesian relaxed-clock method to estimate the relative evolutionary rates of 22 small mammal taxa distributed across northwestern North America. We found that estimates of the relative molecular substitution rate for each taxon were consistent across the range of sampling schemes that we compared. Using three different reference rates, we rescaled the relative rates so that they could be used to estimate absolute evolutionary timescales. Accounting for rate variation among taxa led to temporal shifts in our skyline-plot estimates of demographic history, highlighting both uniform and idiosyncratic evolutionary responses to directional climate trends for distinct ecological subsets of the small mammal community. Our approach can be used in evolutionary analyses of populations from multiple species, including comparative demographic studies.

  4. Ambiguity Function and Resolution Characteristic Analysis of DVB-S Signal for Passive Radar

    Directory of Open Access Journals (Sweden)

    Jin Wei

    2012-12-01

    Full Text Available This paper gives the performance research on the ambiguity function and resolution of passive radar based on DVB-S (Digital Video Broadcasting-Satellite signal. The radar system structure and signal model of DVB-S signal are firstly studied, then the ambiguity function of DVB-S signal is analyzed. At last, it has been obtained how the bistatic radar position impacts the resolution. Theoretical analyses and computer simulation show that DVB-S signal is applicable as an illuminator for passive radar.

  5. Ras-dva1 small GTPase regulates telencephalon development in Xenopus laevis embryos by controlling Fgf8 and Agr signaling at the anterior border of the neural plate

    Directory of Open Access Journals (Sweden)

    Maria B. Tereshina

    2014-07-01

    Full Text Available We previously found that the small GTPase Ras-dva1 is essential for the telencephalic development in Xenopus laevis because Ras-dva1 controls the Fgf8-mediated induction of FoxG1 expression, a key telencephalic regulator. In this report, we show, however, that Ras-dva1 and FoxG1 are expressed in different groups of cells; whereas Ras-dva1 is expressed in the outer layer of the anterior neural fold, FoxG1 and Fgf8 are activated in the inner layer from which the telencephalon is derived. We resolve this paradox by demonstrating that Ras-dva1 is involved in the transduction of Fgf8 signal received by cells in the outer layer, which in turn send a feedback signal that stimulates FoxG1 expression in the inner layer. We show that this feedback signal is transmitted by secreted Agr proteins, the expression of which is activated in the outer layer by mediation of Ras-dva1 and the homeodomain transcription factor Otx2. In turn, Agrs are essential for maintaining Fgf8 and FoxG1 expression in cells at the anterior neural plate border. Our finding reveals a novel feedback loop mechanism based on the exchange of Fgf8 and Agr signaling between neural and non-neural compartments at the anterior margin of the neural plate and demonstrates a key role of Ras-dva1 in this mechanism.

  6. Problems of formation of the financial resources of small businesses

    Directory of Open Access Journals (Sweden)

    Gorbunova Irina Ivanovna

    2014-05-01

    Full Text Available Article is devoted problems of formation of financial resources of small enterprises. In article kinds and sources of financing of small enterprises are analysed, the estimation of influence of external and internal factors on formation of financial resources of small enterprises is given.

  7. Can we use PCA to detect small signals in noisy data?

    Science.gov (United States)

    Spiegelberg, Jakob; Rusz, Ján

    2017-01-01

    Principal component analysis (PCA) is among the most commonly applied dimension reduction techniques suitable to denoise data. Focusing on its limitations to detect low variance signals in noisy data, we discuss how statistical and systematical errors occur in PCA reconstructed data as a function of the size of the data set, which extends the work of Lichtert and Verbeeck, (2013) [16]. Particular attention is directed towards the estimation of bias introduced by PCA and its influence on experiment design. Aiming at the denoising of large matrices, nullspace based denoising (NBD) is introduced. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. MiRNA-mediated regulation of cell signaling and homeostasis in the early mouse embryo.

    Science.gov (United States)

    Pernaute, Barbara; Spruce, Thomas; Rodriguez, Tristan A; Manzanares, Miguel

    2011-02-15

    At the time of implantation the mouse embryo is composed of three tissues the epiblast, trophectoderm and primitive endoderm. As development progresses the epiblast goes on to form the foetus whilst the trophectoderm and primitive endoderm give rise to extra-embryonic structures with important roles in embryo patterning and nutrition. Dramatic changes in gene expression occur during early embryo development and these require regulation at different levels. miRNAs are small non coding RNAs that have emerged over the last decade as important post-transcriptional repressors of gene expression. The roles played by miRNAs during early mammalian development are only starting to be elucidated. In order to gain insight into the function of miRNAs in the different lineages of the early mouse embryo we have analysed in depth the phenotype of embryos and extra-embryonic stem cells mutant for the miRNA maturation protein Dicer. This study revealed that miRNAs are involved in regulating cell signaling and homeostasis in the early embryo. Specifically, we identified a role for miRNAs in regulating the Erk signaling pathway in the extra-embryonic endoderm, cell cycle progression in extra-embryonic tissues and apoptosis in the epiblast.

  9. PASA - A Program for Automated Protein NMR Backbone Signal Assignment by Pattern-Filtering Approach

    International Nuclear Information System (INIS)

    Xu Yizhuang; Wang Xiaoxia; Yang Jun; Vaynberg, Julia; Qin Jun

    2006-01-01

    We present a new program, PASA (Program for Automated Sequential Assignment), for assigning protein backbone resonances based on multidimensional heteronuclear NMR data. Distinct from existing programs, PASA emphasizes a per-residue-based pattern-filtering approach during the initial stage of the automated 13 C α and/or 13 C β chemical shift matching. The pattern filter employs one or multiple constraints such as 13 C α /C β chemical shift ranges for different amino acid types and side-chain spin systems, which helps to rule out, in a stepwise fashion, improbable assignments as resulted from resonance degeneracy or missing signals. Such stepwise filtering approach substantially minimizes early false linkage problems that often propagate, amplify, and ultimately cause complication or combinatorial explosion of the automation process. Our program (http://www.lerner.ccf.org/moleccard/qin/) was tested on four representative small-large sized proteins with various degrees of resonance degeneracy and missing signals, and we show that PASA achieved the assignments efficiently and rapidly that are fully consistent with those obtained by laborious manual protocols. The results demonstrate that PASA may be a valuable tool for NMR-based structural analyses, genomics, and proteomics

  10. A simple beam analyser

    International Nuclear Information System (INIS)

    Lemarchand, G.

    1977-01-01

    (ee'p) experiments allow to measure the missing energy distribution as well as the momentum distribution of the extracted proton in the nucleus versus the missing energy. Such experiments are presently conducted on SACLAY's A.L.S. 300 Linac. Electrons and protons are respectively analysed by two spectrometers and detected in their focal planes. Counting rates are usually low and include time coincidences and accidentals. Signal-to-noise ratio is dependent on the physics of the experiment and the resolution of the coincidence, therefore it is mandatory to get a beam current distribution as flat as possible. Using new technologies has allowed to monitor in real time the behavior of the beam pulse and determine when the duty cycle can be considered as being good with respect to a numerical basis

  11. Rational design of DKK3 structure-based small peptides as antagonists of Wnt signaling pathway and in silico evaluation of their efficiency.

    Directory of Open Access Journals (Sweden)

    Mansour Poorebrahim

    Full Text Available Dysregulated Wnt signaling pathway is highly associated with the pathogenesis of several human cancers. Dickkopf proteins (DKKs are thought to inhibit Wnt signaling pathway through binding to lipoprotein receptor-related protein (LRP 5/6. In this study, based on the 3-dimensional (3D structure of DKK3 Cys-rich domain 2 (CRD2, we have designed and developed several peptide inhibitors of Wnt signaling pathway. Modeller 9.15 package was used to predict 3D structure of CRD2 based on the Homology modeling (HM protocol. After refinement and minimization with GalaxyRefine and NOMAD-REF servers, the quality of selected models was evaluated utilizing VADAR, SAVES and ProSA servers. Molecular docking studies as well as literature-based information revealed two distinct boxes located at CRD2 which are actively involved in the DKK3-LRP5/6 interaction. A peptide library was constructed conducting the backrub sequence tolerance scanning protocol in Rosetta3.5 according to the DKK3-LRP5/6 binding sites. Seven tolerated peptides were chosen and their binding affinity and stability were improved by some logical amino acid substitutions. Molecular dynamics (MD simulations of peptide-LRP5/6 complexes were carried out using GROMACS package. After evaluation of binding free energies, stability, electrostatic potential and some physicochemical properties utilizing computational approaches, three peptides (PEP-I1, PEP-I3 and PEP-II2 demonstrated desirable features. However, all seven improved peptides could sufficiently block the Wnt-binding site of LRP6 in silico. In conclusion, we have designed and improved several small peptides based on the LRP6-binding site of CRD2 of DKK3. These peptides are highly capable of binding to LRP6 in silico, and may prevent the formation of active Wnt-LRP6-Fz complex.

  12. The yeast three-hybrid system as an experimental platform to identify proteins interacting with small signaling molecules in plant cells: Potential and limitations

    Directory of Open Access Journals (Sweden)

    Stéphanie eCottier

    2011-12-01

    Full Text Available Chemical genetics is a powerful scientific strategy that utilizes small bioactive molecules as experimental tools to unravel biological processes. Bioactive compounds occurring in nature represent an enormous diversity of structures that can be used to dissect functions of biological systems. Once the bioactivity of a natural or synthetic compound has been critically evaluated the challenge remains to identify its molecular target and mode of action, which usually is a time consuming and labor-intensive process. To facilitate this task, we decided to implement the yeast three-hybrid (Y3H technology as a general experimental platform to scan the whole Arabidopsis proteome for targets of small signaling molecules. The Y3H technology is based on the yeast two-hybrid system and allows direct cloning of proteins that interact in vivo with a synthetic hybrid ligand, which comprises the biologically active molecule of interest covalently linked to methotrexate (Mtx. In yeast nucleus the hybrid ligand connects two fusion proteins: the Mtx part binding to dihydrofolate reductase fused to a DNA binding domain (encoded in the yeast strain, and the bioactive molecule part binding to its potential protein target fused to a DNA activating domain (encoded on a cDNA expression vector. During cDNA library screening, the formation of this ternary, transcriptional activator complex leads to reporter gene activation in yeast cells, and thereby allows selection of the putative targets of small bioactive molecules of interest. Here we present the strategy and experimental details for construction and application of a Y3H platform, including chemical synthesis of different hybrid ligands, construction of suitable cDNA libraries, the choice of yeast strains, and appropriate screening conditions. Based on the results obtained and the current literature we discussed the perspectives and limitations of the Y3H approach for identifying targets of small bioactive molecules.

  13. Digital signal processing reveals circadian baseline oscillation in majority of mammalian genes.

    Directory of Open Access Journals (Sweden)

    Andrey A Ptitsyn

    2007-06-01

    Full Text Available In mammals, circadian periodicity has been described for gene expression in the hypothalamus and multiple peripheral tissues. It is accepted that 10%-15% of all genes oscillate in a daily rhythm, regulated by an intrinsic molecular clock. Statistical analyses of periodicity are limited by the small size of datasets and high levels of stochastic noise. Here, we propose a new approach applying digital signal processing algorithms separately to each group of genes oscillating in the same phase. Combined with the statistical tests for periodicity, this method identifies circadian baseline oscillation in almost 100% of all expressed genes. Consequently, circadian oscillation in gene expression should be evaluated in any study related to biological pathways. Changes in gene expression caused by mutations or regulation of environmental factors (such as photic stimuli or feeding should be considered in the context of changes in the amplitude and phase of genetic oscillations.

  14. Chromatic signals control proboscis movements during hovering flight in the hummingbird hawkmoth Macroglossum stellatarum.

    Science.gov (United States)

    Goyret, Joaquín; Kelber, Almut

    2012-01-01

    Most visual systems are more sensitive to luminance than to colour signals. Animals resolve finer spatial detail and temporal changes through achromatic signals than through chromatic ones. Probably, this explains that detection of small, distant, or moving objects is typically mediated through achromatic signals. Macroglossum stellatarum are fast flying nectarivorous hawkmoths that inspect flowers with their long proboscis while hovering. They can visually control this behaviour using floral markings known as nectar guides. Here, we investigate whether this is mediated by chromatic or achromatic cues. We evaluated proboscis placement, foraging efficiency, and inspection learning of naïve moths foraging on flower models with coloured markings that offered either chromatic, achromatic or both contrasts. Hummingbird hawkmoths could use either achromatic or chromatic signals to inspect models while hovering. We identified three, apparently independent, components controlling proboscis placement: After initial contact, 1) moths directed their probing towards the yellow colour irrespectively of luminance signals, suggesting a dominant role of chromatic signals; and 2) moths tended to probe mainly on the brighter areas of models that offered only achromatic signals. 3) During the establishment of the first contact, naïve moths showed a tendency to direct their proboscis towards the small floral marks independent of their colour or luminance. Moths learned to find nectar faster, but their foraging efficiency depended on the flower model they foraged on. Our results imply that M. stellatarum can perceive small patterns through colour vision. We discuss how the different informational contents of chromatic and luminance signals can be significant for the control of flower inspection, and visually guided behaviours in general.

  15. Techniques for Scaling Up Analyses Based on Pre-interpretations

    DEFF Research Database (Denmark)

    Gallagher, John Patrick; Henriksen, Kim Steen; Banda, Gourinath

    2005-01-01

    a variety of analyses, both generic (such as mode analysis) and program-specific (with respect to a type describing some particular property of interest). Previous work demonstrated the approach using pre-interpretations over small domains. In this paper we present techniques that allow the method...

  16. Zero curvature-surface driven small objects

    Science.gov (United States)

    Dou, Xiaoxiao; Li, Shanpeng; Liu, Jianlin

    2017-08-01

    In this study, we investigate the spontaneous migration of small objects driven by surface tension on a catenoid, formed by a layer of soap constrained by two rings. Although the average curvature of the catenoid is zero at each point, the small objects always migrate to the position near the ring. The force and energy analyses have been performed to uncover the mechanism, and it is found that the small objects distort the local shape of the liquid film, thus making the whole system energetically favorable. These findings provide some inspiration to design microfluidics, aquatic robotics, and miniature boats.

  17. Study on the Particular Accounting Practices of Small and Medium Companies

    Directory of Open Access Journals (Sweden)

    Cristina Nicolaescu

    2011-12-01

    Full Text Available This article aims to analyse the particularities of small and medium companies in Romania in order to propose a set of practices in accounting terms for these economic entities. To this end has started from the best practice recommendation adopted by the European Commission in November 2008 and guidelines developed by the Small and Medium Practices Committee of the International Federation of Accountants, trying to adapt them to a concrete situation, to the particular situation of small and medium enterprises of Romania. The study features were analysed economic and psycho-social, determined by the mentality of small and medium business owners in Romania and their attitudes about accounting information

  18. Intensity and directionality of bat echolocation signals

    DEFF Research Database (Denmark)

    Jakobsen, Lasse; Brinkløv, Signe; Surlykke, Annemarie

    2013-01-01

    will increase signal directionality in the field along with intensity thus increasing sonar range. During the last phase of prey pursuit, vespertilionid bats broaden their echolocation beam considerably, probably to counter evasive maneuvers of eared prey. We highlight how multiple call parameters (frequency......The paper reviews current knowledge of intensity and directionality of bat echolocation signals. Recent studies have revealed that echolocating bats can be much louder than previously believed. Bats previously dubbed "whispering" can emit calls with source levels up to 110 dB SPL at 10 cm......, duration, intensity, and directionality of echolocation signals) in unison define the search volume probed by bats and in turn how bats perceive their surroundings. Small changes to individual parameters can, in combination, drastically change the bat's perception, facilitating successful navigation...

  19. Confidence Level Computation for Combining Searches with Small Statistics

    OpenAIRE

    Junk, Thomas

    1999-01-01

    This article describes an efficient procedure for computing approximate confidence levels for searches for new particles where the expected signal and background levels are small enough to require the use of Poisson statistics. The results of many independent searches for the same particle may be combined easily, regardless of the discriminating variables which may be measured for the candidate events. The effects of systematic uncertainty in the signal and background models are incorporated ...

  20. Phosphoproteomics-based systems analysis of signal transduction networks

    Directory of Open Access Journals (Sweden)

    Hiroko eKozuka-Hata

    2012-01-01

    Full Text Available Signal transduction systems coordinate complex cellular information to regulate biological events such as cell proliferation and differentiation. Although the accumulating evidence on widespread association of signaling molecules has revealed essential contribution of phosphorylation-dependent interaction networks to cellular regulation, their dynamic behavior is mostly yet to be analyzed. Recent technological advances regarding mass spectrometry-based quantitative proteomics have enabled us to describe the comprehensive status of phosphorylated molecules in a time-resolved manner. Computational analyses based on the phosphoproteome dynamics accelerate generation of novel methodologies for mathematical analysis of cellular signaling. Phosphoproteomics-based numerical modeling can be used to evaluate regulatory network elements from a statistical point of view. Integration with transcriptome dynamics also uncovers regulatory hubs at the transcriptional level. These omics-based computational methodologies, which have firstly been applied to representative signaling systems such as the epidermal growth factor receptor pathway, have now opened up a gate for systems analysis of signaling networks involved in immune response and cancer.

  1. Tunable signal processing in synthetic MAP kinase cascades.

    Science.gov (United States)

    O'Shaughnessy, Ellen C; Palani, Santhosh; Collins, James J; Sarkar, Casim A

    2011-01-07

    The flexibility of MAPK cascade responses enables regulation of a vast array of cell fate decisions, but elucidating the mechanisms underlying this plasticity is difficult in endogenous signaling networks. We constructed insulated mammalian MAPK cascades in yeast to explore how intrinsic and extrinsic perturbations affect the flexibility of these synthetic signaling modules. Contrary to biphasic dependence on scaffold concentration, we observe monotonic decreases in signal strength as scaffold concentration increases. We find that augmenting the concentration of sequential kinases can enhance ultrasensitivity and lower the activation threshold. Further, integrating negative regulation and concentration variation can decouple ultrasensitivity and threshold from the strength of the response. Computational analyses show that cascading can generate ultrasensitivity and that natural cascades with different kinase concentrations are innately biased toward their distinct activation profiles. This work demonstrates that tunable signal processing is inherent to minimal MAPK modules and elucidates principles for rational design of synthetic signaling systems. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. AsHSP17, a creeping bentgrass small heat shock protein modulates plant photosynthesis and ABA-dependent and independent signalling to attenuate plant response to abiotic stress.

    Science.gov (United States)

    Sun, Xinbo; Sun, Chunyu; Li, Zhigang; Hu, Qian; Han, Liebao; Luo, Hong

    2016-06-01

    Heat shock proteins (HSPs) are molecular chaperones that accumulate in response to heat and other abiotic stressors. Small HSPs (sHSPs) belong to the most ubiquitous HSP subgroup with molecular weights ranging from 12 to 42 kDa. We have cloned a new sHSP gene, AsHSP17 from creeping bentgrass (Agrostis stolonifera) and studied its role in plant response to environmental stress. AsHSP17 encodes a protein of 17 kDa. Its expression was strongly induced by heat in both leaf and root tissues, and by salt and abscisic acid (ABA) in roots. Transgenic Arabidopsis plants constitutively expressing AsHSP17 exhibited enhanced sensitivity to heat and salt stress accompanied by reduced leaf chlorophyll content and decreased photosynthesis under both normal and stressed conditions compared to wild type. Overexpression of AsHSP17 also led to hypersensitivity to exogenous ABA and salinity during germination and post-germinative growth. Gene expression analysis indicated that AsHSP17 modulates expression of photosynthesis-related genes and regulates ABA biosynthesis, metabolism and ABA signalling as well as ABA-independent stress signalling. Our results suggest that AsHSP17 may function as a protein chaperone to negatively regulate plant responses to adverse environmental stresses through modulating photosynthesis and ABA-dependent and independent signalling pathways. © 2015 John Wiley & Sons Ltd.

  3. Small-angle neutron scattering and rheological analyses of nanoemulsion for cosmetics

    International Nuclear Information System (INIS)

    Kume, Takuji

    2014-01-01

    A stable nanoemulsion consisting of nanometer-sized oil droplets in water having a self-standing capability was prepared by high-pressure emulsification. Rheological measurements show that the nanoemulsion has a high viscosity and a yield stress. Small-angle neutron scattering (SANS) revealed the presence of an ordered crystal-like lattice structure in addition to spherical domains with a diameter of ca. 30 nm. Nonfluidity of nanoemulsion is ascribed to crystal-like lattice structure of nanodroplets. A mixed solution of 2-hydroxyethyl cellulose and the nanoemulsion has shear-thickening behavior (shear-induced gelation). Real-time SANS measurements with a Couette geometry as a function of shear rate (Rheo-SANS) revealed that a possible mechanism of gelation was proposed from the viewpoint of shear-induced percolation transition. Furthermore, mixtures of the nanoemulsion and poly(acrylic acid) solutions were opaque and kept the same interdomain distance and high viscosity. We estimated that it had phase-separated structure between nanoemulsion phase and poly(acrylic acid) solution phase. (author)

  4. High-fat diet feeding alters metabolic response to fasting/non fasting conditions. Effect on caveolin expression and insulin signalling.

    Science.gov (United States)

    Gómez-Ruiz, Ana; Milagro, Fermín I; Campión, Javier; Martínez, J Alfredo; de Miguel, Carlos

    2011-04-13

    The effect of food intake on caveolin expression in relation to insulin signalling was studied in skeletal muscle and adipocytes from retroperitoneal (RP) and subcutaneous (SC) adipose tissue, comparing fasted (F) to not fasted (NF) rats that had been fed a control or high-fat (HF) diet for 72 days. Serum glucose was analysed enzymatically and insulin and leptin by ELISA. Caveolins and insulin signalling intermediaries (IR, IRS-1 and 2 and GLUT4) were determined by RT-PCR and western blotting. Caveolin and IR phosphorylation was measured by immunoprecipitation. Data were analysed with Mann-Whitney U test. High-fat fed animals showed metabolic alterations and developed obesity and insulin resistance. In skeletal muscle, food intake (NF) induced activation of IR and increased expression of IRS-2 in control animals with normal metabolic response. HF animals became overweight, hyperglycaemic, hyperinsulinemic, hyperleptinemic and showed insulin resistance. In skeletal muscle of these animals, food intake (NF) also induced IRS-2 expression together with IR, although this was not active. Caveolin 3 expression in this tissue was increased by food intake (NF) in animals fed either diet. In RP adipocytes of control animals, food intake (NF) decreased IR and IRS-2 expression but increased that of GLUT4. A similar but less intense response was found in SC adipocytes. Food intake (NF) did not change caveolin expression in RP adipocytes with either diet, but in SC adipocytes of HF animals a reduction was observed. Food intake (NF) decreased caveolin-1 phosphorylation in RP but increased it in SC adipocytes of control animals, whereas it increased caveolin-2 phosphorylation in both types of adipocytes independently of the diet. Animals fed a control-diet show a normal response to food intake (NF), with activation of the insulin signalling pathway but without appreciable changes in caveolin expression, except a small increase of caveolin-3 in muscle. Animals fed a high-fat diet

  5. Learning in and beyond Small Business Advisory Programmes

    Science.gov (United States)

    Parker, Rachel Louise; Hine, Damian

    2012-01-01

    The purpose of this paper is to analyse how participants learn in small business advisory programmes and to explore the impact of these learning programmes on the development of reflective learning dispositions in participants. The research involves two case studies of small business advisory programmes in Queensland, a state of Australia. One…

  6. The Role of Small Towns in Local Place Making

    Directory of Open Access Journals (Sweden)

    Csurgó Bernadett

    2016-12-01

    Full Text Available Self-promotion and reinterpretation of local identity is becoming increasingly important in rural communities. Local identity building is succeeded very differently by rural municipalities and regions. The paper analyses the role of small towns in local identity creation. There are varying interpretations of places in Hungary as ways of achieving meaningful territorialisation. Small towns based on their leading and central position within the micro regions can dominate the place-making processes. Using the example of six Hungarian rural micro-regions we analyse how rural small towns position themselves by local image building. The aim of this paper is to investigate interactions between territorial position and innovative capacity of rural towns through the analysis of symbolisation process and image building. We purpose to introduce a concept of a place oriented approach and demonstrate its usefulness for analysis of rural innovation and place-based development. The case-studies are based on qualitative methods: document-analysis, semi-structured interviews, transect walking and participatory observation. The paper analyses the process of local community and identity building in six rural micro-regions. We seek to understand how small towns position themselves in place-making, the aim of ‘placing’ themselves in the territorial hierarchy of the settlements of micro region. Our results suggest that small towns play very different roles in local image building. Characteristics and territorial scope of local cultural heritage significantly determine the innovative capacity of small towns in local image building where there is a wide range of meanings procedures and processes of place-making.

  7. A Robust Bayesian Truth Serum for Non-binary Signals

    OpenAIRE

    Radanovic, Goran; Faltings, Boi

    2013-01-01

    Several mechanisms have been proposed for incentivizing truthful reports of a private signals owned by rational agents, among them the peer prediction method and the Bayesian truth serum. The robust Bayesian truth serum (RBTS) for small populations and binary signals is particularly interesting since it does not require a common prior to be known to the mechanism. We further analyze the problem of the common prior not known to the mechanism and give several results regarding the restrictions ...

  8. Gated integrator with signal baseline subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.

    1996-12-17

    An ultrafast, high precision gated integrator includes an opamp having differential inputs. A signal to be integrated is applied to one of the differential inputs through a first input network, and a signal indicative of the DC offset component of the signal to be integrated is applied to the other of the differential inputs through a second input network. A pair of electronic switches in the first and second input networks define an integrating period when they are closed. The first and second input networks are substantially symmetrically constructed of matched components so that error components introduced by the electronic switches appear symmetrically in both input circuits and, hence, are nullified by the common mode rejection of the integrating opamp. The signal indicative of the DC offset component is provided by a sample and hold circuit actuated as the integrating period begins. The symmetrical configuration of the integrating circuit improves accuracy and speed by balancing out common mode errors, by permitting the use of high speed switching elements and high speed opamps and by permitting the use of a small integrating time constant. The sample and hold circuit substantially eliminates the error caused by the input signal baseline offset during a single integrating window. 5 figs.

  9. Gated integrator with signal baseline subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xucheng (Lisle, IL)

    1996-01-01

    An ultrafast, high precision gated integrator includes an opamp having differential inputs. A signal to be integrated is applied to one of the differential inputs through a first input network, and a signal indicative of the DC offset component of the signal to be integrated is applied to the other of the differential inputs through a second input network. A pair of electronic switches in the first and second input networks define an integrating period when they are closed. The first and second input networks are substantially symmetrically constructed of matched components so that error components introduced by the electronic switches appear symmetrically in both input circuits and, hence, are nullified by the common mode rejection of the integrating opamp. The signal indicative of the DC offset component is provided by a sample and hold circuit actuated as the integrating period begins. The symmetrical configuration of the integrating circuit improves accuracy and speed by balancing out common mode errors, by permitting the use of high speed switching elements and high speed opamps and by permitting the use of a small integrating time constant. The sample and hold circuit substantially eliminates the error caused by the input signal baseline offset during a single integrating window.

  10. [Plant signaling peptides. Cysteine-rich peptides].

    Science.gov (United States)

    Ostrowski, Maciej; Kowalczyk, Stanisław

    2015-01-01

    Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

  11. Simultaneous multichannel signal transfers via chaos in a recurrent neural network.

    Science.gov (United States)

    Soma, Ken-ichiro; Mori, Ryota; Sato, Ryuichi; Furumai, Noriyuki; Nara, Shigetoshi

    2015-05-01

    We propose neural network model that demonstrates the phenomenon of signal transfer between separated neuron groups via other chaotic neurons that show no apparent correlations with the input signal. The model is a recurrent neural network in which it is supposed that synchronous behavior between small groups of input and output neurons has been learned as fragments of high-dimensional memory patterns, and depletion of neural connections results in chaotic wandering dynamics. Computer experiments show that when a strong oscillatory signal is applied to an input group in the chaotic regime, the signal is successfully transferred to the corresponding output group, although no correlation is observed between the input signal and the intermediary neurons. Signal transfer is also observed when multiple signals are applied simultaneously to separate input groups belonging to different memory attractors. In this sense simultaneous multichannel communications are realized, and the chaotic neural dynamics acts as a signal transfer medium in which the signal appears to be hidden.

  12. Expressional and functional analyses of transcription factors activated by BMP-4s signaling in early xenopus embryo; BMP-4 shigunaru dentatsu kiko to sono hyoteki kakunai tensha inshi ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Maeno, Mitsugu [Niigata University, Niigata (Japan). Faculty of Science

    1998-12-16

    The expression and physiological function of two transcription factors, GATA-2 and Xmsx-1, in amphibian embryos has been analyzed. The expression of these mRNAs in embryonic cells were firmly regulated by the BMP-4 signaling, that plays a central role in the formation of ventral tissues. The microinjection studies of GATA-2 RNA into embryonic cells suggested that this factor functions in two adjacent germ layers, mesoderm and ectoderm, to participate in blood cell formation in ventral area of embryo. Embryos injected with Xmsx-1 RNA, but not with GATA-2, in dorsal blastomeres exhibited a ventralized phenotype, with microcephaly and swollen abdomen. Thus, Xmsx-1 is a ventralizing agent. However, on the basis of molecular marker analyses, Xmsx-1 did not promote erythropoietic differentiation, but promoted muscle tissue formation. It has been concluded that Xmsx-1 si a target transcription factor of the BMP-4 signaling, but possesses a distinct activity on dorso-ventral patterning of mesodermal tissues. (author)

  13. The evolution of the small business and entrepreneurship field: A bibliometric investigation of articles published in the International Small Business Journal

    OpenAIRE

    Volery, Thierry; Mazzarol, Tim

    2015-01-01

    Abstract This article analyses the evolution of the small business management and entrepreneurship fields as reflected in articles published in its premier journal, the International Small Business Journal. It investigates the evolution of the fields through bibliometric examination of all 660 articles published between 1982 and 2012. While small business management has remained the main focus of the journal, there has been a significant growth in the number of articles focusing specif...

  14. Importance of a diffusion-dominant small volume to activate cell-secreted soluble factor signaling in embryonic stem cell culture in microbioreactors: a mathematical model based study.

    Science.gov (United States)

    Chowdhury, Mohammad Mahfuz; Fujii, Teruo; Sakai, Yasuyuki

    2013-07-01

    In our previous studies, we observed that cell-secreted BMP4 had a prominent influence on mouse embryonic stem cell (mESC) behaviors in a membrane-based two-chambered microbioreactor (MB), but not in a macro-scale culture (6-well plate/6WP). In this study, we investigated how the physical aspects of these cultures regulated BMP4 signaling by developing mathematical models of the cultures. The models estimated signaling activity in the cultures by considering size of the undifferentiated mESC colonies and their growth, diffusion of BMP4, and BMP4 trafficking process in the colonies. The models successfully depicted measured profile of BMP4 concentration in the culture medium which was two times higher in the MB than that in the 6WP during 5-day culture. The models estimated that, owing to the small volume and the membrane, cells were exposed to a higher BMP4 concentration in the top chamber of the MB than that in the 6WP culture. The higher concentration of BMP4 induced a higher concentration of BMP4-bound receptor in the colony in the MB than in the 6WP, thereby leading to the higher activation of BMP4 signaling in the MB. The models also predicted that the size of the MB, but not that of the 6WP, was suitable for maximizing BMP4 accumulation and upregulating its signaling. This study will be helpful in analyzing culture systems, designing microfluidic devices for controlling ESC or other cell behavior. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. Analysis of Crossing Speed of the Pedestrians in Marked and Unmarked Crosswalks in the Signalized and Un-Signalized Intersections (Case Study: Rasht city)

    Science.gov (United States)

    Behbahani, Hamid; Najafi Moghaddam Gilani, Vahid; Jahangir Samet, Mehdi; Salehfard, Reza

    2017-10-01

    Pedestrians affect the traffic in the signalized and un-signalized intersections. Therefore, identifying the behavioural features of the pedestrians is of great importance and may result in better designing facilities for them. In this study, by shooting the four intersections in Rasht for 15 hours and inventory from 4568 pedestrians, crossing speed of the pedestrians in the marked crosswalks and unmarked crosswalks was evaluated and analysed. Results showed that pedestrians‧ crossing speed in the marked crosswalks is higher than their crossing speed in the unmarked crosswalks in both signalized and un-signalized intersections. Moreover, in the unmarked crosswalks in the signalized intersections, 15th percentile speed of male pedestrians, female pedestrians and group of pedestrians’ decrease 6.4%, 5.4% and 12.2%, respectively, compared with the 15th percentile speed in the marked crosswalks. Above-mentioned values in the unmarked crosswalks in the un-signalized intersections for male pedestrians, female pedestrians, and group of pedestrians decrease 1.2%, 3.8%, and 1.4%, respectively.

  16. Dynamics in atomic signaling games

    KAUST Repository

    Fox, Michael J.

    2015-04-08

    We study an atomic signaling game under stochastic evolutionary dynamics. There are a finite number of players who repeatedly update from a finite number of available languages/signaling strategies. Players imitate the most fit agents with high probability or mutate with low probability. We analyze the long-run distribution of states and show that, for sufficiently small mutation probability, its support is limited to efficient communication systems. We find that this behavior is insensitive to the particular choice of evolutionary dynamic, a property that is due to the game having a potential structure with a potential function corresponding to average fitness. Consequently, the model supports conclusions similar to those found in the literature on language competition. That is, we show that efficient languages eventually predominate the society while reproducing the empirical phenomenon of linguistic drift. The emergence of efficiency in the atomic case can be contrasted with results for non-atomic signaling games that establish the non-negligible possibility of convergence, under replicator dynamics, to states of unbounded efficiency loss.

  17. Dynamics in atomic signaling games

    KAUST Repository

    Fox, Michael J.; Touri, Behrouz; Shamma, Jeff S.

    2015-01-01

    We study an atomic signaling game under stochastic evolutionary dynamics. There are a finite number of players who repeatedly update from a finite number of available languages/signaling strategies. Players imitate the most fit agents with high probability or mutate with low probability. We analyze the long-run distribution of states and show that, for sufficiently small mutation probability, its support is limited to efficient communication systems. We find that this behavior is insensitive to the particular choice of evolutionary dynamic, a property that is due to the game having a potential structure with a potential function corresponding to average fitness. Consequently, the model supports conclusions similar to those found in the literature on language competition. That is, we show that efficient languages eventually predominate the society while reproducing the empirical phenomenon of linguistic drift. The emergence of efficiency in the atomic case can be contrasted with results for non-atomic signaling games that establish the non-negligible possibility of convergence, under replicator dynamics, to states of unbounded efficiency loss.

  18. Hedgehog signaling contributes to basic fibroblast growth factor-regulated fibroblast migration

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhong Xin [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Sun, Cong Cong [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Wenzhou People' s Hospital, Wenzhou, Zhejiang (China); Ting Zhu, Yu; Wang, Ying; Wang, Tao; Chi, Li Sha; Cai, Wan Hui [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Zheng, Jia Yong [Wenzhou People' s Hospital, Wenzhou, Zhejiang (China); Zhou, Xuan [Ningbo First Hospital, Ningbo, Zhejiang (China); Cong, Wei Tao [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Li, Xiao Kun, E-mail: proflxk@163.com [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Jin, Li Tai, E-mail: jin_litai@126.com [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China)

    2017-06-15

    Fibroblast migration is a central process in skin wound healing, which requires the coordination of several types of growth factors. bFGF, a well-known fibroblast growth factor (FGF), is able to accelerate fibroblast migration; however, the underlying mechanism of bFGF regulation fibroblast migration remains unclear. Through the RNA-seq analysis, we had identified that the hedgehog (Hh) canonical pathway genes including Smoothened (Smo) and Gli1, were regulated by bFGF. Further analysis revealed that activation of the Hh pathway via up-regulation of Smo promoted fibroblast migration, invasion, and skin wound healing, but which significantly reduced by GANT61, a selective antagonist of Gli1/Gli2. Western blot analyses and siRNA transfection assays demonstrated that Smo acted upstream of phosphoinositide 3-kinase (PI3K)-c-Jun N-terminal kinase (JNK)-β-catenin to promote cell migration. Moreover, RNA-seq and qRT-PCR analyses revealed that Hh pathway genes including Smo and Gli1 were under control of β-catenin, suggesting that β-catenin turn feedback activates Hh signaling. Taken together, our analyses identified a new bFGF-regulating mechanism by which Hh signaling regulates human fibroblast migration, and the data presented here opens a new avenue for the wound healing therapy. - Highlights: • bFGF regulates Hedgehog (Hh) signaling in fibroblasts. • The Smo and Gli two master regulators of Hh signaling positively regulate fibroblast migration. • Smo facilitates β-catenin nuclear translocation via activation PI3K/JNK/GSK3β. • β-catenin positively regulates fibroblast cell migration and the expression of Hh signaling genes including Smo and Gli.

  19. Hedgehog signaling contributes to basic fibroblast growth factor-regulated fibroblast migration

    International Nuclear Information System (INIS)

    Zhu, Zhong Xin; Sun, Cong Cong; Ting Zhu, Yu; Wang, Ying; Wang, Tao; Chi, Li Sha; Cai, Wan Hui; Zheng, Jia Yong; Zhou, Xuan; Cong, Wei Tao; Li, Xiao Kun; Jin, Li Tai

    2017-01-01

    Fibroblast migration is a central process in skin wound healing, which requires the coordination of several types of growth factors. bFGF, a well-known fibroblast growth factor (FGF), is able to accelerate fibroblast migration; however, the underlying mechanism of bFGF regulation fibroblast migration remains unclear. Through the RNA-seq analysis, we had identified that the hedgehog (Hh) canonical pathway genes including Smoothened (Smo) and Gli1, were regulated by bFGF. Further analysis revealed that activation of the Hh pathway via up-regulation of Smo promoted fibroblast migration, invasion, and skin wound healing, but which significantly reduced by GANT61, a selective antagonist of Gli1/Gli2. Western blot analyses and siRNA transfection assays demonstrated that Smo acted upstream of phosphoinositide 3-kinase (PI3K)-c-Jun N-terminal kinase (JNK)-β-catenin to promote cell migration. Moreover, RNA-seq and qRT-PCR analyses revealed that Hh pathway genes including Smo and Gli1 were under control of β-catenin, suggesting that β-catenin turn feedback activates Hh signaling. Taken together, our analyses identified a new bFGF-regulating mechanism by which Hh signaling regulates human fibroblast migration, and the data presented here opens a new avenue for the wound healing therapy. - Highlights: • bFGF regulates Hedgehog (Hh) signaling in fibroblasts. • The Smo and Gli two master regulators of Hh signaling positively regulate fibroblast migration. • Smo facilitates β-catenin nuclear translocation via activation PI3K/JNK/GSK3β. • β-catenin positively regulates fibroblast cell migration and the expression of Hh signaling genes including Smo and Gli.

  20. Hyperspectral small animal fluorescence imaging: spectral selection imaging

    Science.gov (United States)

    Leavesley, Silas; Jiang, Yanan; Patsekin, Valery; Hall, Heidi; Vizard, Douglas; Robinson, J. Paul

    2008-02-01

    Molecular imaging is a rapidly growing area of research, fueled by needs in pharmaceutical drug-development for methods for high-throughput screening, pre-clinical and clinical screening for visualizing tumor growth and drug targeting, and a growing number of applications in the molecular biology fields. Small animal fluorescence imaging employs fluorescent probes to target molecular events in vivo, with a large number of molecular targeting probes readily available. The ease at which new targeting compounds can be developed, the short acquisition times, and the low cost (compared to microCT, MRI, or PET) makes fluorescence imaging attractive. However, small animal fluorescence imaging suffers from high optical scattering, absorption, and autofluorescence. Much of these problems can be overcome through multispectral imaging techniques, which collect images at different fluorescence emission wavelengths, followed by analysis, classification, and spectral deconvolution methods to isolate signals from fluorescence emission. We present an alternative to the current method, using hyperspectral excitation scanning (spectral selection imaging), a technique that allows excitation at any wavelength in the visible and near-infrared wavelength range. In many cases, excitation imaging may be more effective at identifying specific fluorescence signals because of the higher complexity of the fluorophore excitation spectrum. Because the excitation is filtered and not the emission, the resolution limit and image shift imposed by acousto-optic tunable filters have no effect on imager performance. We will discuss design of the imager, optimizing the imager for use in small animal fluorescence imaging, and application of spectral analysis and classification methods for identifying specific fluorescence signals.

  1. A systems biology approach for miRNA-mRNA expression patterns analysis in non-small cell lung cancer.

    Science.gov (United States)

    Najafi, Ali; Tavallaei, Mahmood; Hosseini, Sayed Mostafa

    2016-01-01

    Non-small cell lung cancers (NSCLCs) is a prevalent and heterogeneous subtype of lung cancer accounting for 85 percent of patients. MicroRNAs (miRNAs), a class of small endogenous non-coding RNAs, incorporate into regulation of gene expression post-transcriptionally. Therefore, deregulation of miRNAs' expression has provided further layers of complexity to the molecular etiology and pathogenesis of different diseases and malignancies. Although, until now considerable number of studies has been carried out to illuminate this complexity in NSCLC, they have remained less effective in their goal due to lack of a holistic and integrative systems biology approach which considers all natural elaborations of miRNAs' function. It is able to reliably nominate most affected signaling pathways and therapeutic target genes by deregulated miRNAs during a particular pathological condition. Herein, we utilized a holistic systems biology approach, based on appropriate re-analyses of microarray datasets followed by reliable data filtering, to analyze integrative and combinatorial deregulated miRNA-mRNA interaction network in NSCLC, aiming to ascertain miRNA-dysregulated signaling pathway and potential therapeutic miRNAs and mRNAs which represent a lion' share during various aspects of NSCLC's pathogenesis. Our systems biology approach introduced and nominated 1) important deregulated miRNAs in NSCLCs compared with normal tissue 2) significant and confident deregulated mRNAs which were anti-correlatively targeted by deregulated miRNA in NSCLCs and 3) dysregulated signaling pathways in association with deregulated miRNA-mRNAs interactions in NSCLCs. These results introduce possible mechanism of function of deregulated miRNAs and mRNAs in NSCLC that could be used as potential therapeutic targets.

  2. SU-F-J-137: Intrafractional Change of the Relationship Between Internal Fiducials and External Breathing Signal in Pancreatic Cancer Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, N; Murphy, J; Simpson, D; Cervino, L [University of California, San Diego, La Jolla, CA (United States)

    2016-06-15

    Purpose: The use of respiratory gating for management of breathing motion during stereotactic body radiation therapy (SBRT) relies on a consistent relationship between the breathing signal and the actual position of the internal target. This relationship was investigated in patients treated for pancreatic cancer. Methods: Four patients with pancreatic cancer undergoing SBRT that had implanted fiducials in the tumor were included in this study. Treatment plans were generated based on the exhale phases (30–70%) from the pre-treatment 4DCT. The margin between the internal target volume (ITV) and the planning target volume was three mm. After patient setup using cone-beam CT, simultaneous fluoroscopic imaging and breathing motion monitoring were used during at least three breathing cycles to verify the fiducial position and to optimize the gating window. After treatment, fluoroscopic images were acquired for verification purposes and exported for retrospective analyses. Fiducial positions were determined using a template-matching algorithm. For each dataset, we established a linear relationship between the fiducial position and the anterior-posterior (AP) breathing signal. The relationships before and after treatment were compared and the dose distribution impact evaluated. Results: Seven pre- and post-treatment fluoroscopic pairs were available for fiducial position analyses in the superior-inferior (SI) and left-right (LR) directions, and five in the AP direction. Time between image acquisitions was typically six to eight minutes. An average absolute change of 1.2±0.7 mm (range: 0.1–1.7) of the SI fiducial position relative to the external signal was found. Corresponding numbers for the LR and AP fiducial positions were 0.9±1.0 mm (range: 0.2–3.0) and 0.5±0.4 mm (range: 0.2–1.2), respectively. The dose distribution impact was small in both the ITV and organs-at-risk. Conclusion: The relationship change between fiducial position and external breathing

  3. SU-F-J-137: Intrafractional Change of the Relationship Between Internal Fiducials and External Breathing Signal in Pancreatic Cancer Stereotactic Body Radiation Therapy

    International Nuclear Information System (INIS)

    Pettersson, N; Murphy, J; Simpson, D; Cervino, L

    2016-01-01

    Purpose: The use of respiratory gating for management of breathing motion during stereotactic body radiation therapy (SBRT) relies on a consistent relationship between the breathing signal and the actual position of the internal target. This relationship was investigated in patients treated for pancreatic cancer. Methods: Four patients with pancreatic cancer undergoing SBRT that had implanted fiducials in the tumor were included in this study. Treatment plans were generated based on the exhale phases (30–70%) from the pre-treatment 4DCT. The margin between the internal target volume (ITV) and the planning target volume was three mm. After patient setup using cone-beam CT, simultaneous fluoroscopic imaging and breathing motion monitoring were used during at least three breathing cycles to verify the fiducial position and to optimize the gating window. After treatment, fluoroscopic images were acquired for verification purposes and exported for retrospective analyses. Fiducial positions were determined using a template-matching algorithm. For each dataset, we established a linear relationship between the fiducial position and the anterior-posterior (AP) breathing signal. The relationships before and after treatment were compared and the dose distribution impact evaluated. Results: Seven pre- and post-treatment fluoroscopic pairs were available for fiducial position analyses in the superior-inferior (SI) and left-right (LR) directions, and five in the AP direction. Time between image acquisitions was typically six to eight minutes. An average absolute change of 1.2±0.7 mm (range: 0.1–1.7) of the SI fiducial position relative to the external signal was found. Corresponding numbers for the LR and AP fiducial positions were 0.9±1.0 mm (range: 0.2–3.0) and 0.5±0.4 mm (range: 0.2–1.2), respectively. The dose distribution impact was small in both the ITV and organs-at-risk. Conclusion: The relationship change between fiducial position and external breathing

  4. Multivariate analyses of small theropod dinosaur teeth and implications for paleoecological turnover through time.

    Directory of Open Access Journals (Sweden)

    Derek W Larson

    Full Text Available Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian. It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth

  5. Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time

    Science.gov (United States)

    Larson, Derek W.; Currie, Philip J.

    2013-01-01

    Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian). It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed) from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth will help illuminate

  6. Analyses of cavitation instabilities in ductile metals

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2007-01-01

    Cavitation instabilities have been predicted for a single void in a ductile metal stressed under high triaxiality conditions. In experiments for a ceramic reinforced by metal particles a single dominant void has been observed on the fracture surface of some of the metal particles bridging a crack......, and also tests for a thin ductile metal layer bonding two ceramic blocks have indicated rapid void growth. Analyses for these material configurations are discussed here. When the void radius is very small, a nonlocal plasticity model is needed to account for observed size-effects, and recent analyses......, while the surrounding voids are represented by a porous ductile material model in terms of a field quantity that specifies the variation of the void volume fraction in the surrounding metal....

  7. Use of green fluorescent protein fusions to analyse the N- and C-terminal signal peptides of GPI-anchored cell wall proteins in Candida albicans.

    Science.gov (United States)

    Mao, Yuxin; Zhang, Zimei; Wong, Brian

    2003-12-01

    Glycophosphatidylinositol (GPI)-anchored proteins account for 26-35% of the Candida albicans cell wall. To understand the signals that regulate these proteins' cell surface localization, green fluorescent protein (GFP) was fused to the N- and C-termini of the C. albicans cell wall proteins (CWPs) Hwp1p, Als3p and Rbt5p. C. albicans expressing all three fusion proteins were fluorescent at the cell surface. GFP was released from membrane fractions by PI-PLC and from cell walls by beta-glucanase, which implied that GFP was GPI-anchored to the plasma membrane and then covalently attached to cell wall glucans. Twenty and 25 amino acids, respectively, from the N- and C-termini of Hwp1p were sufficient to target GFP to the cell surface. C-terminal substitutions that are permitted by the omega rules (G613D, G613N, G613S, G613A, G615S) did not interfere with GFP localization, whereas some non-permitted substitutions (G613E, G613Q, G613R, G613T and G615Q) caused GFP to accumulate in intracellular ER-like structures and others (G615C, G613N/G615C and G613D/G615C) did not. These results imply that (i) GFP fusions can be used to analyse the N- and C-terminal signal peptides of GPI-anchored CWPs, (ii) the omega amino acid in Hwp1p is G613, and (iii) C can function at the omega+2 position in C. albicans GPI-anchored proteins.

  8. Multiple Spectral Ratio Analyses Reveal Earthquake Source Spectra of Small Earthquakes and Moment Magnitudes of Microearthquakes

    Science.gov (United States)

    Uchide, T.; Imanishi, K.

    2016-12-01

    Spectral studies for macroscopic earthquake source parameters are helpful for characterizing earthquake rupture process and hence understanding earthquake source physics and fault properties. Those studies require us mute wave propagation path and site effects in spectra of seismograms to accentuate source effect. We have recently developed the multiple spectral ratio method [Uchide and Imanishi, BSSA, 2016] employing many empirical Green's function (EGF) events to reduce errors from the choice of EGF events. This method helps us estimate source spectra more accurately as well as moment ratios among reference and EGF events, which are useful to constrain the seismic moment of microearthquakes. First, we focus on earthquake source spectra. The source spectra have generally been thought to obey the omega-square model with single corner-frequency. However recent studies imply the existence of another corner frequency for some earthquakes. We analyzed small shallow inland earthquakes (3.5 multiple spectral ratio analyses. For 20000 microearthquakes in Fukushima Hamadori and northern Ibaraki prefecture area, we found that the JMA magnitudes (Mj) based on displacement or velocity amplitude are systematically below Mw. The slope of the Mj-Mw relation is 0.5 for Mj 5. We propose a fitting curve for the obtained relationship as Mw = (1/2)Mj + (1/2)(Mjγ + Mcorγ)1/γ+ c, where Mcor is a corner magnitude, γ determines the sharpness of the corner, and c denotes an offset. We obtained Mcor = 4.1, γ = 5.6, and c = -0.47 to fit the observation. The parameters are useful for characterizing the Mj-Mw relationship. This non-linear relationship affects the b-value of the Gutenberg-Richter law. Quantitative discussions on b-values are affected by the definition of magnitude to use.

  9. Effects of HVDC on power systems small signal angle stability

    Energy Technology Data Exchange (ETDEWEB)

    Custodio, D.T.; Paccini, R.O.; Kopcak, I.; Costa, V.F. da [State University of Campinas (UNICAMP), SP (Brazil). School of Electrical and Computer Engineering. Power Systems Dept.], Emails: totti@dsee.fee.unicamp.br, rodrigo@dsee.fee.unicamp.br, kopcak@dsee.fee.unicamp.br, vivaldo@dsee.fee.unicamp.br

    2009-07-01

    In this paper, a didactic method for parameters tuning of the Power Oscillation Damper (POD) coupled to the HVDC constant current controller is proposed utilizing the MATLAB package with a control system toolbox. First, modal analysis is done from the system state matrix to determine the critical mode and oscillation natural frequency. Input and output linearized matrixes are built to single-input and single-output (SISO) control systems. The phase to be compensated between the active power flow in the parallel AC inter-tie and the current reference signal of the HVDC constant current controller is obtained from the Nyquist theorem. Following, the POD time constants are obtained. Finally, the static gain of the POD is tuned based on the root locus method of the classical control theory. Simulations results prove that the DC power modulation is efficient to damp the AC power oscillations. This method is straightforward because only involves matrix operation. (author)

  10. Development and application of model RAIA uranium on-line analyser

    International Nuclear Information System (INIS)

    Dong Yanwu; Song Yufen; Zhu Yaokun; Cong Peiyuan; Cui Songru

    1999-01-01

    The working principle, structure, adjustment and application of model RAIA on-line analyser are reported. The performance of this instrument is reliable. For identical sample, the signal fluctuation in continuous monitoring for four months is less than +-1%. According to required measurement range, appropriate length of sample cell is chosen. The precision of measurement process is better than 1% at 100 g/L U. The detection limit is 50 mg/L. The uranium concentration in process stream can be displayed automatically and printed at any time. It presents 4∼20 mA current signal being proportional to the uranium concentration. This makes a long step towards process continuous control and computer management

  11. NPP Krsko small break LOCA analysis

    International Nuclear Information System (INIS)

    Mavko, B.; Petelin, S.; Peterlin, G.

    1987-01-01

    Parametric analysis of small break loss of coolant accident for the Krsko NPP was calculated by using RELAP5/MOD1 computer code. The model that was used in our calculations has been improved over several years and was previously tested in simulation (s) of start-up tests and known NPP Krsko transients. In our calculations we modelled automatic actions initiated by control, safety and protection systems. We also modelled the required operator actions as specified in emergency operating instructions. In small-break LOCA calculations, we varied break sizes in the cold leg. The influence of steam generator tube plugging on small break LOCA accidents was also analysed. (author)

  12. So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae).

    Science.gov (United States)

    Sueur, Jérôme; Mackie, David; Windmill, James F C

    2011-01-01

    To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2) SPL rms re 2.10(-5) Pa with a peak at 99.2 (85.7-104.6) SPL re 2.10(-5) Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

  13. So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae.

    Directory of Open Access Journals (Sweden)

    Jérôme Sueur

    Full Text Available To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2 SPL rms re 2.10(-5 Pa with a peak at 99.2 (85.7-104.6 SPL re 2.10(-5 Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

  14. Instrument for real-time pulse-shape analysis of slit-scan flow cytometry signals

    NARCIS (Netherlands)

    van Oven, C.; Aten, J. A.

    1990-01-01

    An instrument is described which analyses shapes of fluorescence profiles generated by particles passing through the focussed laser beam of a flow cytometer. The output signal of this pulse-shape analyzer is used as input for the signal processing electronics of a commercial flow cytometer system.

  15. Quantum Dot Devices for Optical Signal Processing

    DEFF Research Database (Denmark)

    Chen, Yaohui

    and the continuum. Additional to the conventional time-domain modeling scheme, a small-signal perturbation analysis has been used to assist the investigation of harmonic modulation properties. The static properties of quantum dot devices, for example high saturation power, have been quantitatively analyzed....... Additional to the static linear amplication properties, we focus on exploring the gain dynamics on the time scale ranging from sub-picosecond to nanosecond. In terms of optical signals that have been investigated, one is the simple sinusoidally modulated optical carrier with a typical modulation frequency....... We also investigate the gain dynamics in the presence of pulsed signals, in particular the steady gain response to a periodic pulse trains with various time periods. Additional to the analysis of high speed patterning free amplication up to 150-200 Gb/s in quantum dot semiconductor optical ampliers...

  16. Brain networks: small-worlds, after all?

    International Nuclear Information System (INIS)

    Muller, Lyle; Destexhe, Alain; Rudolph-Lilith, Michelle

    2014-01-01

    Since its introduction, the ‘small-world’ effect has played a central role in network science, particularly in the analysis of the complex networks of the nervous system. From the cellular level to that of interconnected cortical regions, many analyses have revealed small-world properties in the networks of the brain. In this work, we revisit the quantification of small-worldness in neural graphs. We find that neural graphs fall into the ‘borderline’ regime of small-worldness, residing close to that of a random graph, especially when the degree sequence of the network is taken into account. We then apply recently introducted analytical expressions for clustering and distance measures, to study this borderline small-worldness regime. We derive theoretical bounds for the minimal and maximal small-worldness index for a given graph, and by semi-analytical means, study the small-worldness index itself. With this approach, we find that graphs with small-worldness equivalent to that observed in experimental data are dominated by their random component. These results provide the first thorough analysis suggesting that neural graphs may reside far away from the maximally small-world regime. (paper)

  17. Brain networks: small-worlds, after all?

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Lyle; Destexhe, Alain; Rudolph-Lilith, Michelle [Unité de Neurosciences, Information et Complexité (UNIC), Centre National de la Recherche Scientifique (CNRS), 1 Avenue de la Terrasse, Gif-sur-Yvette (France)

    2014-10-01

    Since its introduction, the ‘small-world’ effect has played a central role in network science, particularly in the analysis of the complex networks of the nervous system. From the cellular level to that of interconnected cortical regions, many analyses have revealed small-world properties in the networks of the brain. In this work, we revisit the quantification of small-worldness in neural graphs. We find that neural graphs fall into the ‘borderline’ regime of small-worldness, residing close to that of a random graph, especially when the degree sequence of the network is taken into account. We then apply recently introducted analytical expressions for clustering and distance measures, to study this borderline small-worldness regime. We derive theoretical bounds for the minimal and maximal small-worldness index for a given graph, and by semi-analytical means, study the small-worldness index itself. With this approach, we find that graphs with small-worldness equivalent to that observed in experimental data are dominated by their random component. These results provide the first thorough analysis suggesting that neural graphs may reside far away from the maximally small-world regime. (paper)

  18. A real time ECG signal processing application for arrhythmia detection on portable devices

    Science.gov (United States)

    Georganis, A.; Doulgeraki, N.; Asvestas, P.

    2017-11-01

    Arrhythmia describes the disorders of normal heart rate, which, depending on the case, can even be fatal for a patient with severe history of heart disease. The purpose of this work is to develop an application for heart signal visualization, processing and analysis in Android portable devices e.g. Mobile phones, tablets, etc. The application is able to retrieve the signal initially from a file and at a later stage this signal is processed and analysed within the device so that it can be classified according to the features of the arrhythmia. In the processing and analysing stage, different algorithms are included among them the Moving Average and Pan Tompkins algorithm as well as the use of wavelets, in order to extract features and characteristics. At the final stage, testing is performed by simulating our application in real-time records, using the TCP network protocol for communicating the mobile with a simulated signal source. The classification of ECG beat to be processed is performed by neural networks.

  19. Cross-talk and information transfer in mammalian and bacterial signaling.

    Directory of Open Access Journals (Sweden)

    Samanthe M Lyons

    Full Text Available In mammalian and bacterial cells simple phosphorylation circuits play an important role in signaling. Bacteria have hundreds of two-component signaling systems that involve phosphotransfer between a receptor and a response regulator. In mammalian cells a similar pathway is the TGF-beta pathway, where extracellular TGF-beta ligands activate cell surface receptors that phosphorylate Smad proteins, which in turn activate many genes. In TGF-beta signaling the multiplicity of ligands begs the question as to whether cells can distinguish signals coming from different ligands, but transduced through a small set of Smads. Here we use information theory with stochastic simulations of networks to address this question. We find that when signals are transduced through only one Smad, the cell cannot distinguish between different levels of the external ligands. Increasing the number of Smads from one to two significantly improves information transmission as well as the ability to discriminate between ligands. Surprisingly, both total information transmitted and the capacity to discriminate between ligands are quite insensitive to high levels of cross-talk between the two Smads. Robustness against cross-talk requires that the average amplitude of the signals are large. We find that smaller systems, as exemplified by some two-component systems in bacteria, are significantly much less robust against cross-talk. For such system sizes phosphotransfer is also less robust against cross-talk than phosphorylation. This suggests that mammalian signal transduction can tolerate a high amount of cross-talk without degrading information content. This may have played a role in the evolution of new functionalities from small mutations in signaling pathways, allowed for the development of cross-regulation and led to increased overall robustness due to redundancy in signaling pathways. On the other hand the lack of cross-regulation observed in many bacterial two

  20. Simulation study on effects of signaling network structure on the developmental increase in complexity

    Energy Technology Data Exchange (ETDEWEB)

    Keranen, Soile V.E.

    2003-04-02

    The developmental increase in structural complexity in multicellular life forms depends on local, often non-periodic differences in gene expression. These depend on a network of gene-gene interactions coded within the organismal genome. To better understand how genomic information generates complex expression patterns, I have modeled the pattern forming behavior of small artificial genomes in virtual blastoderm embryos. I varied several basic properties of these genomic signaling networks, such as the number of genes, the distributions of positive (inductive) and negative (repressive) interactions, and the strengths of gene-gene interactions, and analyzed their effects on developmental pattern formation. The results show how even simple genomes can generate complex non-periodic patterns under suitable conditions. They also show how the frequency of complex patterns depended on the numbers and relative arrangements of positive and negative interactions. For example, negative co-regulation of signaling pathway components increased the likelihood of (complex) patterns relative to differential negative regulation of the pathway components. Interestingly, neither quantitative differences either in strengths of signaling interactions nor multiple response thresholds to signal concentration (as in morphogen gradients) were essential for formation of multiple, spatially unique cell types. Thus, with combinatorial code of gene regulation and hierarchical signaling interactions, it is theoretically possible to organize metazoan embryogenesis with just a small fraction of the metazoan genome. Because even small networks can generate complex patterns when they contain a suitable set of connections, evolution of metazoan complexity may have depended more on selection for favourable configurations of signaling interactions than on the increase in numbers of regulatory genes.

  1. VHF signal power suppression in stratiform and convective precipitation

    Directory of Open Access Journals (Sweden)

    A. J. McDonald

    2006-03-01

    Full Text Available Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer. This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W. Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal suppression.

  2. VHF signal power suppression in stratiform and convective precipitation

    Directory of Open Access Journals (Sweden)

    A. J. McDonald

    2006-03-01

    Full Text Available Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer.

    This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W. Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal

  3. Period doubling and chaos in large area Josephson junctions induced by rf signals

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm

    1985-01-01

    The influence of an applied rf signal on the emitted radiation from a large area Josephson junction is examined. A model of the system is presented in the framework of the one-dimensional sine-Gordon equation. The model linearizes for small and large values of the amplitude of the applied signal...

  4. Development and application of a quantitative multiplexed small GTPase activity assay using targeted proteomics.

    Science.gov (United States)

    Zhang, Cheng-Cheng; Li, Ru; Jiang, Honghui; Lin, Shujun; Rogalski, Jason C; Liu, Kate; Kast, Juergen

    2015-02-06

    Small GTPases are a family of key signaling molecules that are ubiquitously expressed in various types of cells. Their activity is often analyzed by western blot, which is limited by its multiplexing capability, the quality of isoform-specific antibodies, and the accuracy of quantification. To overcome these issues, a quantitative multiplexed small GTPase activity assay has been developed. Using four different binding domains, this assay allows the binding of up to 12 active small GTPase isoforms simultaneously in a single experiment. To accurately quantify the closely related small GTPase isoforms, a targeted proteomic approach, i.e., selected/multiple reaction monitoring, was developed, and its functionality and reproducibility were validated. This assay was successfully applied to human platelets and revealed time-resolved coactivation of multiple small GTPase isoforms in response to agonists and differential activation of these isoforms in response to inhibitor treatment. This widely applicable approach can be used for signaling pathway studies and inhibitor screening in many cellular systems.

  5. Instrument Records And Plays Back Acceleration Signals

    Science.gov (United States)

    Bozeman, Richard J.

    1994-01-01

    Small, battery-powered, hand-held instrument feeds power to accelerometer and records time-varying component of output for 15 seconds in analog form. No power needed to maintain content of memory; memory chip removed after recording and stored indefinitely. Recorded signal plays back at any time up to several years later. Principal advantages: compactness, portability, and low cost.

  6. Rap G protein signal in normal and disordered lymphohematopoiesis.

    Science.gov (United States)

    Minato, Nagahiro

    2013-09-10

    Rap proteins (Rap1, Rap2a, b, c) are small molecular weight GTPases of the Ras family. Rap G proteins mediate diverse cellular events such as cell adhesion, proliferation, and gene activation through various signaling pathways. Activation of Rap signal is regulated tightly by several specific regulatory proteins including guanine nucleotide exchange factors and GTPase-activating proteins. Beyond cell biological studies, increasing attempts have been made in the past decade to define the roles of Rap signal in specific functions of normal tissue systems as well as in cancer. In the immune and hematopoietic systems, Rap signal plays crucial roles in the development and function of essentially all lineages of lymphocytes and hematopoietic cells, and importantly, deregulated Rap signal may lead to unique pathological conditions depending on the affected cell types, including various types of leukemia and autoimmunity. The phenotypical studies have unveiled novel, even unexpected functional aspects of Rap signal in cells from a variety of tissues, providing potentially important clues for controlling human diseases, including malignancy. © 2013 Elsevier Inc. All rights reserved.

  7. Feasibility of Johnson Noise Thermometry based on Digital Signal Processing Techniques

    International Nuclear Information System (INIS)

    Hwang, In Koo; Kim, Yang Mo

    2014-01-01

    This paper presents an implementation strategy of noise thermometry based on a digital signal processing technique and demonstrates its feasibilities. A key factor in its development is how to extract the small thermal noise signal from other noises, for example, random noise from amplifiers and continuous electromagnetic interference from the environment. The proposed system consists of two identical amplifiers and uses a cross correlation function to cancel the random noise of the amplifiers. Then, the external interference noises are eliminated by discriminating the difference in the peaks between the thermal signal and external noise. The gain of the amplifiers is estimated by injecting an already known pilot signal. The experimental simulation results of signal processing methods have demonstrated that the proposed approach is an effective method in eliminating an external noise signal and performing gain correction for development of the thermometry

  8. Small instrument to volcanic seismic signals

    Science.gov (United States)

    Carreras, Normandino; Gomariz, Spartacus; Manuel, Antoni

    2014-05-01

    Currently, the presence of volcanoes represents a threat to their local populations, and for this reason, scientific communities invest resources to monitor seismic activity of an area, and to obtain information to identify risk situations. To perform such monitoring, it can use different general purpose acquisition systems commercially available, but these devices do not meet to the specifications of reduced dimensions, low weight, low power consumption and low cost. These features allow the system works in autonomous mode for a long period of time, and it makes easy to be carried and to be installed. In the line of designing a volcanic acquisition system with the previously mentioned specifications, exists the Volcanology Department of CSIC, developers of a system with some of these specifications. The objective of this work is to improve the energy consumption requirements of the previous system, providing three channels of data acquisition and with the possibility to transmit data acquisition via radio frequency to a base station, allowing operation it in remote mode. The developed acquisition system consists of three very low-power acquisition modules of Texas Instruments (ADS1246), and this is designed to capture information of the three coordinate axes. A microprocessor also of Texas Instruments (MSP430F5438) is used to work in low-power, due to it is ready to run this consumption and also takes advantage the power save mode in certain moments when system is not working. This system is configurable by serial port, and it has a SD memory to storage data. Contrast to the previous system, it has a RF communication module incorporated specially to work in remote mode of Lynx (YLX-TRM8053-025-05), and boasts also with a GPS module which keeps the time reference synchronized with module of SANAV (GM-1315LA). Thanks to this last selection of components, it is designed a small system about 106 x 106 mm. Assuming that the power supply system is working during all the

  9. Audio-visual perception of 3D cinematography: an fMRI study using condition-based and computation-based analyses.

    Directory of Open Access Journals (Sweden)

    Akitoshi Ogawa

    Full Text Available The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion. Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround, 3D with monaural sound (3D-Mono, 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG. The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life

  10. Audio-visual perception of 3D cinematography: an fMRI study using condition-based and computation-based analyses.

    Science.gov (United States)

    Ogawa, Akitoshi; Bordier, Cecile; Macaluso, Emiliano

    2013-01-01

    The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion). Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround), 3D with monaural sound (3D-Mono), 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG). The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life-like stimuli.

  11. Updating signal typing in voice: addition of type 4 signals.

    Science.gov (United States)

    Sprecher, Alicia; Olszewski, Aleksandra; Jiang, Jack J; Zhang, Yu

    2010-06-01

    The addition of a fourth type of voice to Titze's voice classification scheme is proposed. This fourth voice type is characterized by primarily stochastic noise behavior and is therefore unsuitable for both perturbation and correlation dimension analysis. Forty voice samples were classified into the proposed four types using narrowband spectrograms. Acoustic, perceptual, and correlation dimension analyses were completed for all voice samples. Perturbation measures tended to increase with voice type. Based on reliability cutoffs, the type 1 and type 2 voices were considered suitable for perturbation analysis. Measures of unreliability were higher for type 3 and 4 voices. Correlation dimension analyses increased significantly with signal type as indicated by a one-way analysis of variance. Notably, correlation dimension analysis could not quantify the type 4 voices. The proposed fourth voice type represents a subset of voices dominated by noise behavior. Current measures capable of evaluating type 4 voices provide only qualitative data (spectrograms, perceptual analysis, and an infinite correlation dimension). Type 4 voices are highly complex and the development of objective measures capable of analyzing these voices remains a topic of future investigation.

  12. Abnormal diffusion-weighted MRI in medulloblastoma: does it reflect small cell histology?

    International Nuclear Information System (INIS)

    Kotsenas, A.L.; Roth, T.C.; Manness, W.K.; Faerber, E.N.

    1999-01-01

    A 12-year-old boy presented with the classic CT and MRI findings of medulloblastoma and the unusual finding of increased signal on diffusion MRI. The small-cell histology of medulloblastoma may account for the increased signal seen on diffusion MRI. Diffusion MRI with echoplanar technique may be useful in evaluation of these tumors and metastatic disease. (orig.)

  13. Power-law spectra found in plant signal of the Borssele NPP. An analysis using wavelet. Application of wavelet for wide-frequency range investigation and investigation (spectrum) for the secondary system signals

    International Nuclear Information System (INIS)

    Suzudo, T.; Verhoef, J.P.; Tuerkcan, E.

    1996-09-01

    Power-law spectra were found in the temperature signals of the secondary loop in the Borssele Nuclear Power Plant, a PWR in the Netherlands. The coolant temperature before the steam generator inlet was found to fluctuate such that its power spectrum density S, follows S∝f -α , where α is ∝4/3. Analyses using PSD suggested that the value of α is roughly constant over years. Detailed analyses were conducted using wavelet, with the discovery that the power-law appears constantly only at around 0.1 Hz, and the estimated α was found between 1.26 and 1.36. The feedwater pressure signal and feedwater flow rate signal in the same frequency range were white noise and Borwnian motion respectively, and the indication of α=4/3 was not found from them. (orig.)

  14. Agatha: Disentangling period signals from correlated noise in a periodogram framework

    Science.gov (United States)

    Feng, F.; Tuomi, M.; Jones, H. R. A.

    2018-04-01

    Agatha is a framework of periodograms to disentangle periodic signals from correlated noise and to solve the two-dimensional model selection problem: signal dimension and noise model dimension. These periodograms are calculated by applying likelihood maximization and marginalization and combined in a self-consistent way. Agatha can be used to select the optimal noise model and to test the consistency of signals in time and can be applied to time series analyses in other astronomical and scientific disciplines. An interactive web implementation of the software is also available at http://agatha.herts.ac.uk/.

  15. JACoW Lightweight acquisition system for analogue signals

    CERN Document Server

    Bielawski, Bartosz

    2018-01-01

    In a complex machine such as a particle accelerator there are thousands of analogue signals that need monitoring and even more signals that could be used for debugging or as a tool for detecting symptoms of potentially avoidable problems. Usually it is not feasible to acquire and monitor all of these signals not only because of the cost but also because of cabling and space required. The Radio Frequency system in the Large Hadron Collider (LHC) is protected by multiple hardware interlocks that ensure safe operation of klystrons, superconducting cavities and all the other equipment. In parallel, a diagnostic system has been deployed to monitor the health of the klystrons. Due to the limited amount of space and the moderate number of signals to be monitored, a standard approach with a full VME or Compact PCI crate has not been selected. Instead, small embedded industrial computers with Universal Serial Bus (USB) oscilloscopes chosen for the specific application have been installed. This cost effective, rapidly ...

  16. Signal processing for passive detection and classification of underwater acoustic signals

    Science.gov (United States)

    Chung, Kil Woo

    2011-12-01

    This dissertation examines signal processing for passive detection, classification and tracking of underwater acoustic signals for improving port security and the security of coastal and offshore operations. First, we consider the problem of passive acoustic detection of a diver in a shallow water environment. A frequency-domain multi-band matched-filter approach to swimmer detection is presented. The idea is to break the frequency contents of the hydrophone signals into multiple narrow frequency bands, followed by time averaged (about half of a second) energy calculation over each band. Then, spectra composed of such energy samples over the chosen frequency bands are correlated to form a decision variable. The frequency bands with highest Signal/Noise ratio are used for detection. The performance of the proposed approach is demonstrated for experimental data collected for a diver in the Hudson River. We also propose a new referenceless frequency-domain multi-band detector which, unlike other reference-based detectors, does not require a diver specific signature. Instead, our detector matches to a general feature of the diver spectrum in the high frequency range: the spectrum is roughly periodic in time and approximately flat when the diver exhales. The performance of the proposed approach is demonstrated by using experimental data collected from the Hudson River. Moreover, we present detection, classification and tracking of small vessel signals. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification and tracking. This dissertation presents recent improvements aimed at the measurement and separation of ship DEMON (Detection of Envelope Modulation on Noise) acoustic signatures in busy harbor conditions. Ship signature measurements were conducted in the Hudson River and NY Harbor. The DEMON spectra demonstrated much better temporal stability compared with the full ship

  17. Small and Robust Antennas for Concrete Embedded Sensors

    DEFF Research Database (Denmark)

    Rindorf, Lars; Jakobsen, Kaj Bjarne

    2009-01-01

    We study a small antenna for a structural health monitoring sensor. The sensor is cast into concrete. The sensor monitors the humidity and temperature of the concrete, which is a harsh environment. From measured material parameters of the concrete we estimate the signal loss and the antenna detun...

  18. Combinations of SNPs Related to Signal Transduction in Bipolar Disorder

    DEFF Research Database (Denmark)

    Koefoed, Pernille; Andreassen, Ole A; Bennike, Bente

    2011-01-01

    of complex diseases, it may be useful to look at combinations of genotypes. Genes related to signal transmission, e.g., ion channel genes, may be of interest in this respect in the context of bipolar disorder. In the present study, we analysed 803 SNPs in 55 genes related to aspects of signal transmission...... and calculated all combinations of three genotypes from the 3×803 SNP genotypes for 1355 controls and 607 patients with bipolar disorder. Four clusters of patient-specific combinations were identified. Permutation tests indicated that some of these combinations might be related to bipolar disorder. The WTCCC...... in the clusters in the two datasets. The present analyses of the combinations of SNP genotypes support a role for both genetic heterogeneity and interactions in the genetic architecture of bipolar disorder....

  19. SU-F-T-445: Effect of Triaxial Cables and Microdetectors in Small Field Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Das, I; Andersen, A [Indiana University- School of Medicine, Indianapolis, IN (United States)

    2016-06-15

    Purpose: Advances in radiation treatment especially with smaller fields used in SRS, Gamma knife, Tomotherapy, Cyberknife, and IMRT, require a high degree of precision especially with microdetectors for small field dosimetry (Das et al, Med Ph, 35, 206, 2008; Alfonso et al, Med Phys, 35, 5179, 2008). Due to small signal, the triaxial cable becomes critical in terms of signal to noise ratio (SNR) which is studied with microdetectors. Methods: Six high quality triaxial cables, 9.1 meters long from different manufacturers without any defects were acquired along with 5 most popular microdetectors (microdiamond, plastic scintillators, SRS-diode, edge-diode and pinpoint). A dedicated electrometer was used for each combination except W1 which has its own supermax electrometer. A 6MV photon beam from Varian True beam with 100 MU at a 600 MU/min was used. Measurements were made at a depth of 5 cm in water phantom. Field sizes were varied from 0.5 cm to 10 cm square fields. Readings were taken with combination of cables and microdetectors. Results: Signal is dependent on the quality of the connectors, cables and types of microdetector. The readings varied from nC to pC depending on the type of microdetector. The net signal, S, (Sc-Sn), where Sc is signal with chamber and Sn is without chamber is a linear function of sensitive volume, v; (S = α+β•V), where α and β are constants. The standard deviation (SD) in 3 sets of reading with each combination of cable-detector was extremely low <0.02%. As expected the SD is higher in small fields (<3cm). Maximum estimated error was only ±0.2% in cables-detector combinations. Conclusion: The choice of cables has relatively small effect (±0.2%) with microdosimeter and should be accounted in overall error estimation in k value that is needed to convert ratio of reading to dose in small field dosimetry.

  20. SU-F-T-445: Effect of Triaxial Cables and Microdetectors in Small Field Dosimetry

    International Nuclear Information System (INIS)

    Das, I; Andersen, A

    2016-01-01

    Purpose: Advances in radiation treatment especially with smaller fields used in SRS, Gamma knife, Tomotherapy, Cyberknife, and IMRT, require a high degree of precision especially with microdetectors for small field dosimetry (Das et al, Med Ph, 35, 206, 2008; Alfonso et al, Med Phys, 35, 5179, 2008). Due to small signal, the triaxial cable becomes critical in terms of signal to noise ratio (SNR) which is studied with microdetectors. Methods: Six high quality triaxial cables, 9.1 meters long from different manufacturers without any defects were acquired along with 5 most popular microdetectors (microdiamond, plastic scintillators, SRS-diode, edge-diode and pinpoint). A dedicated electrometer was used for each combination except W1 which has its own supermax electrometer. A 6MV photon beam from Varian True beam with 100 MU at a 600 MU/min was used. Measurements were made at a depth of 5 cm in water phantom. Field sizes were varied from 0.5 cm to 10 cm square fields. Readings were taken with combination of cables and microdetectors. Results: Signal is dependent on the quality of the connectors, cables and types of microdetector. The readings varied from nC to pC depending on the type of microdetector. The net signal, S, (Sc-Sn), where Sc is signal with chamber and Sn is without chamber is a linear function of sensitive volume, v; (S = α+β•V), where α and β are constants. The standard deviation (SD) in 3 sets of reading with each combination of cable-detector was extremely low <0.02%. As expected the SD is higher in small fields (<3cm). Maximum estimated error was only ±0.2% in cables-detector combinations. Conclusion: The choice of cables has relatively small effect (±0.2%) with microdosimeter and should be accounted in overall error estimation in k value that is needed to convert ratio of reading to dose in small field dosimetry.

  1. A Computer- Based Digital Signal Processing for Nuclear Scintillator Detectors

    International Nuclear Information System (INIS)

    Ashour, M.A.; Abo Shosha, A.M.

    2000-01-01

    In this paper, a Digital Signal Processing (DSP) Computer-based system for the nuclear scintillation signals with exponential decay is presented. The main objective of this work is to identify the characteristics of the acquired signals smoothly, this can be done by transferring the signal environment from random signal domain to deterministic domain using digital manipulation techniques. The proposed system consists of two major parts. The first part is the high performance data acquisition system (DAQ) that depends on a multi-channel Logic Scope. Which is interfaced with the host computer through the General Purpose Interface Board (GPIB) Ver. IEEE 488.2. Also, a Graphical User Interface (GUI) has been designed for this purpose using the graphical programming facilities. The second of the system is the DSP software Algorithm which analyses, demonstrates, monitoring these data to obtain the main characteristics of the acquired signals; the amplitude, the pulse count, the pulse width, decay factor, and the arrival time

  2. RADAR upper hybrid resonance scattering diagnostics of small-scale fluctuations and waves in tokamak plasmas

    International Nuclear Information System (INIS)

    Bulyiginskiy, D.G.; Gurchenko, A.D.; Gusakov, E.Z.; Korkin, V.V.; Larionov, M.M.; Novik, K.M.; Petrov, Yu.V.; Popov, A.Yu.; Saveliev, A.N.; Selenin, V.L.; Stepanov, A.Yu.

    2001-01-01

    The upper hybrid resonance (UHR) scattering technique possessing such merits as one-dimensional probing geometry, enhancement of cross section, and fine localization of scattering region is modified in the new diagnostics under development to achieve wave number resolution. The fluctuation wave number is estimated in the new technique from the scattering signal time delay measurements. The feasibility of the scheme is checked in the proof of principal experiment in a tokamak. The time delay of the UHR scattering signal exceeding 10 ns is observed. The small scale low frequency density fluctuations are investigated in the UHR RADAR backscattering experiment. The UHR cross-polarization scattering signal related to small scale magnetic fluctuations is observed. The lower hybrid (LH) wave propagation and both linear and nonlinear wave conversion are investigated. The small wavelength (λ≤0.02 cm) high number ion Bernstein harmonics, resulting from the linear wave conversion of the LH wave are observed in a tokamak plasma for the first time

  3. Analysing the 21 cm signal from the epoch of reionization with artificial neural networks

    Science.gov (United States)

    Shimabukuro, Hayato; Semelin, Benoit

    2017-07-01

    The 21 cm signal from the epoch of reionization should be observed within the next decade. While a simple statistical detection is expected with Square Kilometre Array (SKA) pathfinders, the SKA will hopefully produce a full 3D mapping of the signal. To extract from the observed data constraints on the parameters describing the underlying astrophysical processes, inversion methods must be developed. For example, the Markov Chain Monte Carlo method has been successfully applied. Here, we test another possible inversion method: artificial neural networks (ANNs). We produce a training set that consists of 70 individual samples. Each sample is made of the 21 cm power spectrum at different redshifts produced with the 21cmFast code plus the value of three parameters used in the seminumerical simulations that describe astrophysical processes. Using this set, we train the network to minimize the error between the parameter values it produces as an output and the true values. We explore the impact of the architecture of the network on the quality of the training. Then we test the trained network on the new set of 54 test samples with different values of the parameters. We find that the quality of the parameter reconstruction depends on the sensitivity of the power spectrum to the different parameters at a given redshift, that including thermal noise and sample variance decreases the quality of the reconstruction and that using the power spectrum at several redshifts as an input to the ANN improves the quality of the reconstruction. We conclude that ANNs are a viable inversion method whose main strength is that they require a sparse exploration of the parameter space and thus should be usable with full numerical simulations.

  4. 3D analyses of cavitation instabilities accounting for plastic anisotropy

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Tvergaard, Viggo

    2010-01-01

    Full three dimensional cell model analyses are carried out for a solid containing a single small void, in order to determine the critical stress levels for the occurrence of cavitation instabilities. The material models applied are elastic‐viscoplastic, with a small rate‐hardening exponent...... that the quasi‐static solution is well approximated. A special procedure is used to strongly reduce the loading rate a little before the instability occurs. It is found that plastic anisotropy has a significant effect on the level of the critical stress for cavitation instabilities....

  5. An attempt to detect the greenhouse-gas signal in a transient GCM simulation

    International Nuclear Information System (INIS)

    Barnett, T.P.

    1990-01-01

    Results from the GISS model forced by transient greenhouse-gas (GHG) increases are used to demonstrate methods of detecting the theoretically predicted GHG signal. The signal predicted to occur in the surface temperature of the world's ocean since 1958 is not found in the observations but this is not surprising since the signal was small in the first place. The main result of the study is to demonstrate many of the key issues/difficulties that attend the detection problem

  6. Multivariate Analysis for the Processing of Signals

    Directory of Open Access Journals (Sweden)

    Beattie J.R.

    2014-01-01

    Full Text Available Real-world experiments are becoming increasingly more complex, needing techniques capable of tracking this complexity. Signal based measurements are often used to capture this complexity, where a signal is a record of a sample’s response to a parameter (e.g. time, displacement, voltage, wavelength that is varied over a range of values. In signals the responses at each value of the varied parameter are related to each other, depending on the composition or state sample being measured. Since signals contain multiple information points, they have rich information content but are generally complex to comprehend. Multivariate Analysis (MA has profoundly transformed their analysis by allowing gross simplification of the tangled web of variation. In addition MA has also provided the advantage of being much more robust to the influence of noise than univariate methods of analysis. In recent years, there has been a growing awareness that the nature of the multivariate methods allows exploitation of its benefits for purposes other than data analysis, such as pre-processing of signals with the aim of eliminating irrelevant variations prior to analysis of the signal of interest. It has been shown that exploiting multivariate data reduction in an appropriate way can allow high fidelity denoising (removal of irreproducible non-signals, consistent and reproducible noise-insensitive correction of baseline distortions (removal of reproducible non-signals, accurate elimination of interfering signals (removal of reproducible but unwanted signals and the standardisation of signal amplitude fluctuations. At present, the field is relatively small but the possibilities for much wider application are considerable. Where signal properties are suitable for MA (such as the signal being stationary along the x-axis, these signal based corrections have the potential to be highly reproducible, and highly adaptable and are applicable in situations where the data is noisy or

  7. Feeding by whiteflies suppresses downstream jasmonic acid signaling by eliciting salicylic acid signaling.

    Science.gov (United States)

    Zhang, Peng-Jun; Li, Wei-Di; Huang, Fang; Zhang, Jin-Ming; Xu, Fang-Cheng; Lu, Yao-Bin

    2013-05-01

    Phloem-feeding whiteflies in the species complex Bemisia tabaci cause extensive crop damage worldwide. One of the reasons for their "success" is their ability to suppress the effectual jasmonic acid (JA) defenses of the host plant. However, little is understood about the mechanisms underlying whitefly suppression of JA-regulated defenses. Here, we showed that the expression of salicylic acid (SA)-responsive genes (EDS1 and PR1) in Arabidopsis thaliana was significantly enhanced during feeding by whitefly nymphs. Whereas upstream JA-responsive genes (LOX2 and OPR3) also were induced, the downstream JA-responsive gene (VSP1) was repressed, i.e., whiteflies only suppressed downstream JA signaling. Gene-expression analyses with various Arabidopsis mutants, including NahG, npr-1, ein2-1, and dde2-2, revealed that SA signaling plays a key role in the suppression of downstream JA defenses by whitefly feeding. Assays confirmed that SA activation enhanced whitefly performance by suppressing downstream JA defenses.

  8. Manipulation of signaling thresholds in "engineered stem cell niches" identifies design criteria for pluripotent stem cell screens.

    Directory of Open Access Journals (Sweden)

    Raheem Peerani

    Full Text Available In vivo, stem cell fate is regulated by local microenvironmental parameters. Governing parameters in this stem cell niche include soluble factors, extra-cellular matrix, and cell-cell interactions. The complexity of this in vivo niche limits analyses into how individual niche parameters regulate stem cell fate. Herein we use mouse embryonic stem cells (mESC and micro-contact printing (microCP to investigate how niche size controls endogenous signaling thresholds. microCP is used to restrict colony diameter, separation, and degree of clustering. We show, for the first time, spatial control over the activation of the Janus kinase/signal transducer and activator of transcription pathway (Jak-Stat. The functional consequences of this niche-size-dependent signaling control are confirmed by demonstrating that direct and indirect transcriptional targets of Stat3, including members of the Jak-Stat pathway and pluripotency-associated genes, are regulated by colony size. Modeling results and empirical observations demonstrate that colonies less than 100 microm in diameter are too small to maximize endogenous Stat3 activation and that colonies separated by more than 400 microm can be considered independent from each other. These results define parameter boundaries for the use of ESCs in screening studies, demonstrate the importance of context in stem cell responsiveness to exogenous cues, and suggest that niche size is an important parameter in stem cell fate control.

  9. Response of resonant gravitational wave detectors to damped sinusoid signals

    International Nuclear Information System (INIS)

    Pai, A; Celsi, C; Pallottino, G V; D'Antonio, S; Astone, P

    2007-01-01

    Till date, the search for burst signals with resonant gravitational wave (GW) detectors has been done using the δ-function approximation for the signal, which was reasonable due to the very small bandwidth of these detectors. However, now with increased bandwidth (of the order of 10 or more Hz) and with the possibility of comparing results with interferometric GW detectors (broad-band), it is very important to exploit the resonant detectors' capability to detect also signals with specific wave shapes. As a first step, we present a study of the response of resonant GW detectors to damped sinusoids with given frequency and decay time and report on the development of a filter matched to these signals. This study is a preliminary step towards the comprehension of the detector response and of the filtering for signals such as the excitation of stellar quasi-normal modes

  10. The Rac1 hypervariable region in targeting and signaling: a tail of many stories

    NARCIS (Netherlands)

    Lam, B. Daniel; Hordijk, Peter L.

    2013-01-01

    Cellular signaling by small GTPases is critically dependent on proper spatio-temporal orchestration of activation and output. In addition to their core G (guanine nucleotide binding)-domain, small GTPases comprise a hypervariable region (HVR) and a lipid anchor that are generally accepted to control

  11. Analysis of the finescale timing of repeated signals: does shell rapping in hermit crabs signal stamina?

    Science.gov (United States)

    Briffa; Elwood

    2000-01-01

    Hermit crabs, Pagurus bernhardus, sometimes exchange shells after a period of shell rapping, when the initiating or attacking crab brings its shell rapidly and repeatedly into contact with the shell of the noninitiator or defender in a series of bouts. Bouts are separated by pauses, and raps within bouts are separated by very short periods called 'gaps'. Since within-contest variation is missed when signals are studied by averaging performance rates over entire contests, we analysed the fine within-bout structure of this repeated, aggressive signal. We found that the pattern is consistent with high levels of fatigue in initiators. The duration of the gaps between individual raps increased both within bouts and from bout to bout, and we conclude that this activity is costly to perform. Furthermore, long pauses between bouts is correlated with increased vigour of rapping in the subsequent bout, which suggests that the pause allows for recovery from fatigue induced by rapping. These between-bout pauses may be assessed by noninitiators and provide a signal of stamina. Copyright 2000 The Association for the Study of Animal Behaviour.

  12. Nitric oxide-induced signalling in rat lacrimal acinar cells

    DEFF Research Database (Denmark)

    Looms, Dagnia Karen; Tritsaris, K.; Dissing, S.

    2002-01-01

    -adrenergic stimulation and not by a rise in [Ca2+]i alone.   We show that in rat lacrimal acinar cells, NO and cGMP induce Ca2+ release from intracellular stores via G kinase activation. However, the changes in [Ca2+]i are relatively small, suggesting that this pathway plays a modulatory role in Ca2+ signalling, thus...... not by itself causing fast transient increases in [Ca2+]i. In addition, we suggest that endogenously produced NO activated by ß-adrenergic receptor stimulation, plays an important role in signalling to the surrounding tissue....

  13. Re-modulated technology of WDM-PON employing different DQPSK downstream signals

    Science.gov (United States)

    Gao, Chao; Xin, Xiang-jun; Yu, Chong-xiu

    2012-11-01

    This paper proposes a kind of modulation architecture for wavelength-division-multiplexing passive optical network (WDMPON) employing optical differential quadrature phase shift keying (DQPSK) downstream signals and two different modulation formats of re-modulated upstream signals. At the optical line terminal (OLT), 10 Gbit/s signal is modulated with DQPSK. At the optical network unit (ONU), part of the downstream signal is re-modulated with on-off keying (OOK) or inverse-return-to-zero (IRZ). Simulation results show the impact on the system employing NRZ, RZ and carrier-suppressed return-to-zero (CSRZ). The analyses also reflect that the architecture can restrain chromatic dispersion and channel crosstalk, which makes it the best architecture of access network in the future.

  14. Interpopulational Variations in Sexual Chemical Signals of Iberian Wall Lizards May Allow Maximizing Signal Efficiency under Different Climatic Conditions.

    Science.gov (United States)

    Martín, José; Ortega, Jesús; López, Pilar

    2015-01-01

    Sexual signals used in intraspecific communication are expected to evolve to maximize efficacy under a given climatic condition. Thus, chemical secretions of lizards might evolve in the evolutionary time to ensure that signals are perfectly tuned to local humidity and temperature conditions affecting their volatility and therefore their persistence and transmission through the environment. We tested experimentally whether interpopulational altitudinal differences in chemical composition of femoral gland secretions of male Iberian wall lizards (Podarcis hispanicus) have evolved to maximize efficacy of chemical signals in different environmental conditions. Chemical analyses first showed that the characteristics of chemical signals of male lizards differed between two populations inhabiting environments with different climatic conditions in spite of the fact that these two populations are closely related genetically. We also examined experimentally whether the temporal attenuation of the chemical stimuli depended on simulated climatic conditions. Thus, we used tongue-flick essays to test whether female lizards were able to detect male scent marks maintained under different conditions of temperature and humidity by chemosensory cues alone. Chemosensory tests showed that chemical signals of males had a lower efficacy (i.e. detectability and persistence) when temperature and dryness increase, but that these effects were more detrimental for signals of the highest elevation population, which occupies naturally colder and more humid environments. We suggest that the abiotic environment may cause a selective pressure on the form and expression of sexual chemical signals. Therefore, interpopulational differences in chemical profiles of femoral secretions of male P. hispanicus lizards may reflect adaptation to maximize the efficacy of the chemical signal in different climates.

  15. A photocleavable rapamycin conjugate for spatiotemporal control of small GTPase activity.

    Science.gov (United States)

    Umeda, Nobuhiro; Ueno, Tasuku; Pohlmeyer, Christopher; Nagano, Tetsuo; Inoue, Takanari

    2011-01-12

    We developed a novel method to spatiotemporally control the activity of signaling molecules. A newly synthesized photocaged rapamycin derivative induced rapid dimerization of FKBP (FK-506 binding protein) and FRB (FKBP-rapamycin binding protein) upon UV irradiation. With this system and the spatially confined UV irradiation, we achieved subcellularly localized activation of Rac, a member of small GTPases. Our technique offers a powerful approach to studies of dynamic intracellular signaling events.

  16. Temporal separation of the density fluctuation signal measured by light scattering

    International Nuclear Information System (INIS)

    Antar, G.; Devynk, P.; Laviron, C.; Garbet, X.; Sabot, R.; Fenzi, C.; Hennequin, P.; Truc, A.; Quemeneur, A.; Honore, C.; Gervais, F.

    1999-02-01

    On Tore Supra, the frequency spectra of the turbulent fluctuations often have two peaks centered on some positive and negative values. These two peaks correspond to a poloidal motion of electron turbulence in opposite directions. In this paper, a criterion is elaborated allowing us to distinguish, in time, density fluctuations convected in the parallel from those in the anti-parallel direction with respect to the analysing wavevector. Two signals are thus extracted out of one. The validity of our model is experimentally checked up by comparing the auto-correlation coefficients and the frequency spectra computed for the whole and the separated signals. Consequently, the frequency spectrum is studied in detail as a function of the analysing wavenumber leading to an accurate determination of some plasma properties. (authors)

  17. Comparative proteomic analyses reveal that FlbA down-regulates gliT expression and SOD activity in Aspergillus fumigatus.

    Science.gov (United States)

    Shin, Kwang-Soo; Park, Hee-Soo; Kim, Young-Hwan; Yu, Jae-Hyuk

    2013-07-11

    FlbA is a regulator of G-protein signaling protein that plays a central role in attenuating heterotrimeric G-protein mediated vegetative growth signaling in Aspergillus. The deletion of flbA (∆flbA) in the opportunistic human pathogen Aspergillus fumigatus results in accelerated cell death and autolysis in submerged culture. To further investigate the effects of ∆flbA on intracellular protein levels we carried out 2-D proteome analyses of 2-day old submerged cultures of ∆flbA and wild type (WT) strains and observed 160 differentially expressed proteins. Via nano-LC-ESI-MS/MS analyses, we revealed the identity of 10 and 2 proteins exhibiting high and low level accumulation, respectively, in ∆flbA strain. Notably, the GliT protein is accumulated at about 1800-fold higher levels in ∆flbA than WT. Moreover, GliT is secreted at high levels from ∆flbA strain, whereas Sod1 (superoxide dismutase) is secreted at a higher level in WT. Northern blot analyses reveal that ∆flbA results in elevated accumulation of gliT mRNA. Consequently, ∆flbA strain exhibits enhanced tolerance to gliotoxin toxicity. Finally, ∆flbA strain displayed enhanced SOD activity and elevated resistance to menadione and paraquat. In summary, FlbA-mediated signaling control negatively affects cellular responses associated with detoxification of reactive oxygen species and of exogenous gliotoxin in A. fumigatus. Regulator of G protein Signaling (RGS) proteins play crucial roles in fundamental biological processes in filamentous fungi. FlbA is the first studied filamentous fungal RGS protein, yet much remains to be understood about its roles in the opportunistic human pathogen Aspergillus fumigatus. In the present study, we examined the effects of the deletion of flbA using comprehensive analyses of the intra- and extracellular proteomes of A. fumigatus wild type and the flbA deletion mutant. Via MS analyses, we identified 10 proteins exhibiting high level accumulation in the flbA deletion

  18. Ain't necessarily so: review and critique of recent meta-analyses of behavioral medicine interventions in health psychology.

    Science.gov (United States)

    Coyne, James C; Thombs, Brett D; Hagedoorn, Mariet

    2010-03-01

    We examined four meta-analyses of behavioral interventions for adults (Dixon, Keefe, Scipio, Perri, & Abernethy, 2007; Hoffman, Papas, Chatkoff, & Kerns, 2007; Irwin, Cole, & Nicassio, 2006; and Jacobsen, Donovan, Vadaparampil, & Small, 2007) that have appeared in the Evidence Based Treatment Reviews section of Health Psychology. Narrative review. We applied the following criteria to each meta-analysis: (1) whether each meta-analysis was described accurately, adequately, and transparently in the article; (2) whether there was an adequate attempt to deal with methodological quality of the original trials; (3) the extent to which the meta-analysis depended on small, underpowered studies; and (4) the extent to which the meta-analysis provided valid and useful evidence-based recommendations. Across the four meta-analyses, we identified substantial problems with the transparency and completeness with which these meta-analyses were reported, as well as a dependence on small, underpowered trials of generally poor quality. Results of our exercise raise questions about the clinical validity and utility of the conclusions of these meta-analyses. Results should serve as a wake up call to prospective authors, reviewers, and end-users of meta-analyses now appearing in the literature. Copyright 2010 APA, all rights reserved.

  19. Nociceptive tuning by stem cell factor/c-Kit signaling.

    Science.gov (United States)

    Milenkovic, Nevena; Frahm, Christina; Gassmann, Max; Griffel, Carola; Erdmann, Bettina; Birchmeier, Carmen; Lewin, Gary R; Garratt, Alistair N

    2007-12-06

    The molecular mechanisms regulating the sensitivity of sensory circuits to environmental stimuli are poorly understood. We demonstrate here a central role for stem cell factor (SCF) and its receptor, c-Kit, in tuning the responsiveness of sensory neurons to natural stimuli. Mice lacking SCF/c-Kit signaling displayed profound thermal hypoalgesia, attributable to a marked elevation in the thermal threshold and reduction in spiking rate of heat-sensitive nociceptors. Acute activation of c-Kit by its ligand, SCF, resulted in a reduced thermal threshold and potentiation of heat-activated currents in isolated small-diameter neurons and thermal hyperalgesia in mice. SCF-induced thermal hyperalgesia required the TRP family cation channel TRPV1. Lack of c-Kit signaling during development resulted in hypersensitivity of discrete mechanoreceptive neuronal subtypes. Thus, c-Kit can now be grouped with a small family of receptor tyrosine kinases, including c-Ret and TrkA, that control the transduction properties of sensory neurons.

  20. The safety regulation of small-scale coal mines in China: Analysing the interests and influences of stakeholders

    International Nuclear Information System (INIS)

    Song, Xiaoqian; Mu, Xiaoyi

    2013-01-01

    Small scale coal mines (SCMs) have played an important role in China’s energy supply. At the same time, they also suffer from many social, economic, environmental, and safety problems. The Chinese government has made considerable efforts to strengthen the safety regulation of the coal mining industry. Yet, few of these efforts have proven to be very effective. This paper analyzes the interests and influences of key stakeholders in the safety regulation of SCMs, which includes the safety regulator, the local government, the mine owner, and mineworkers. We argue that the effective regulation of coal mine safety must both engage and empower mineworkers. - Highlights: ► Small scale coal mines have played an important role in China's energy supply. ► We analyze the interests and influences of key stakeholders in the safety regulation of small coal mines. ► The mineworkers have the strongest interest but least influence. ► An effective regulation must engage the mineworkers, organize, and empower them.

  1. SH2/SH3 signaling proteins.

    Science.gov (United States)

    Schlessinger, J

    1994-02-01

    SH2 and SH3 domains are small protein modules that mediate protein-protein interactions in signal transduction pathways that are activated by protein tyrosine kinases. SH2 domains bind to short phosphotyrosine-containing sequences in growth factor receptors and other phosphoproteins. SH3 domains bind to target proteins through sequences containing proline and hydrophobic amino acids. SH2 and SH3 domain containing proteins, such as Grb2 and phospholipase C gamma, utilize these modules in order to link receptor and cytoplasmic protein tyrosine kinases to the Ras signaling pathway and to phosphatidylinositol hydrolysis, respectively. The three-dimensional structures of several SH2 and SH3 domains have been determined by NMR and X-ray crystallography, and the molecular basis of their specificity is beginning to be unveiled.

  2. Efficient secretion of small proteins in mammalian cells relies on Sec62-dependent posttranslational translocation

    Science.gov (United States)

    Lakkaraju, Asvin K. K.; Thankappan, Ratheeshkumar; Mary, Camille; Garrison, Jennifer L.; Taunton, Jack; Strub, Katharina

    2012-01-01

    Mammalian cells secrete a large number of small proteins, but their mode of translocation into the endoplasmic reticulum is not fully understood. Cotranslational translocation was expected to be inefficient due to the small time window for signal sequence recognition by the signal recognition particle (SRP). Impairing the SRP pathway and reducing cellular levels of the translocon component Sec62 by RNA interference, we found an alternate, Sec62-dependent translocation path in mammalian cells required for the efficient translocation of small proteins with N-terminal signal sequences. The Sec62-dependent translocation occurs posttranslationally via the Sec61 translocon and requires ATP. We classified preproteins into three groups: 1) those that comprise ≤100 amino acids are strongly dependent on Sec62 for efficient translocation; 2) those in the size range of 120–160 amino acids use the SRP pathway, albeit inefficiently, and therefore rely on Sec62 for efficient translocation; and 3) those larger than 160 amino acids depend on the SRP pathway to preserve a transient translocation competence independent of Sec62. Thus, unlike in yeast, the Sec62-dependent translocation pathway in mammalian cells serves mainly as a fail-safe mechanism to ensure efficient secretion of small proteins and provides cells with an opportunity to regulate secretion of small proteins independent of the SRP pathway. PMID:22648169

  3. Coil concepts for rapid and motion-compensated MR-Imaging of small animals

    International Nuclear Information System (INIS)

    Korn, Matthias

    2009-01-01

    In this work radiofrequency-coils for the imaging of small animals in clinical whole-body MRI-systems were developed. Therefore in a first step single-channel solenoids were designed and characterized. The solenoids had two and three windings respectively, which were implemented as double wires to increase the homogeneity of the receive profile. These coils allow the acquisition of whole-body images of mice with high signal-to-noise ratio and homogeneity over a distance of at least 6.3 cm. Since many imaging experiments require rapid image acquisition, in the next step a novel coil concept was developed, which, due to its geometry, enables parallel imaging in arbitrary directions. A prototype was assembled and tested on phantom and small-animal experiments. With an accelerating factor of R=2, the difference of the SNR in all directions from the theoretical maximum, was less than 1%. In order to compensate physiological motion by the self-gating technique, in this work a coil is presented for the first time, which selectively amplifies the self-gating signal, while - due to a optical detuning technique - preserving the homogeneous illumination of the image. In vivo experiments on a small animal show an amplification of the self-gating signal by at least 40%. (orig.)

  4. Small molecule ErbB inhibitors decrease proliferative signaling and promote apoptosis in philadelphia chromosome-positive acute lymphoblastic leukemia.

    Directory of Open Access Journals (Sweden)

    Mary E Irwin

    Full Text Available The presence of the Philadelphia chromosome in patients with acute lymphoblastic leukemia (Ph(+ALL is a negative prognostic indicator. Tyrosine kinase inhibitors (TKI that target BCR/ABL, such as imatinib, have improved treatment of Ph(+ALL and are generally incorporated into induction regimens. This approach has improved clinical responses, but molecular remissions are seen in less than 50% of patients leaving few treatment options in the event of relapse. Thus, identification of additional targets for therapeutic intervention has potential to improve outcomes for Ph+ALL. The human epidermal growth factor receptor 2 (ErbB2 is expressed in ~30% of B-ALLs, and numerous small molecule inhibitors are available to prevent its activation. We analyzed a cohort of 129 ALL patient samples using reverse phase protein array (RPPA with ErbB2 and phospho-ErbB2 antibodies and found that activity of ErbB2 was elevated in 56% of Ph(+ALL as compared to just 4.8% of Ph(-ALL. In two human Ph+ALL cell lines, inhibition of ErbB kinase activity with canertinib resulted in a dose-dependent decrease in the phosphorylation of an ErbB kinase signaling target p70S6-kinase T389 (by 60% in Z119 and 39% in Z181 cells at 3 µM. Downstream, phosphorylation of S6-kinase was also diminished in both cell lines in a dose-dependent manner (by 91% in both cell lines at 3 µM. Canertinib treatment increased expression of the pro-apoptotic protein Bim by as much as 144% in Z119 cells and 49% in Z181 cells, and further produced caspase-3 activation and consequent apoptotic cell death. Both canertinib and the FDA-approved ErbB1/2-directed TKI lapatinib abrogated proliferation and increased sensitivity to BCR/ABL-directed TKIs at clinically relevant doses. Our results suggest that ErbB signaling is an additional molecular target in Ph(+ALL and encourage the development of clinical strategies combining ErbB and BCR/ABL kinase inhibitors for this subset of ALL patients.

  5. Structure-Based Design and Synthesis of a Small Molecule that Exhibits Anti-inflammatory Activity by Inhibition of MyD88-mediated Signaling to Bacterial Toxin Exposure.

    Science.gov (United States)

    Alam, Shahabuddin; Javor, Sacha; Degardin, Melissa; Ajami, Dariush; Rebek, Mitra; Kissner, Teri L; Waag, David M; Rebek, Julius; Saikh, Kamal U

    2015-08-01

    Both Gram-positive and Gram-negative pathogens or pathogen-derived components, such as staphylococcal enterotoxins (SEs) and endotoxin (LPS) exposure, activate MyD88-mediated pro-inflammatory cellular immunity for host defense. However, dysregulated MyD88-mediated signaling triggers exaggerated immune response that often leads to toxic shock and death. Previously, we reported a small molecule compound 1 mimicking BB-loop structure of MyD88 was capable of inhibiting pro-inflammatory response to SEB exposure in mice. In this study, we designed a dimeric structure compound 4210 covalently linked with compound 1 by a non-polar cyclohexane linker which strongly inhibited the production of pro-inflammatory cytokines in human primary cells to SEB (IC50 1-50 μm) or LPS extracted from Francisella tularensis, Escherichia coli, or Burkholderia mallei (IC50 10-200 μm). Consistent with cytokine inhibition, in a ligand-induced cell-based reporter assay, compound 4210 inhibited Burkholderia mallei or LPS-induced MyD88-mediated NF-kB-dependent expression of reporter activity (IC50 10-30 μm). Furthermore, results from a newly expressed MyD88 revealed that 4210 inhibited MyD88 dimer formation which is critical for pro-inflammatory signaling. Importantly, a single administration of compound 4210 in mice showed complete protection from lethal toxin challenge. Collectively, these results demonstrated that compound 4210 inhibits toxin-induced inflated pro-inflammatory immune signaling, thus displays a potential bacterial toxin therapeutic. © 2014 John Wiley & Sons A/S.

  6. Quantitative measurement of intervertebral disc signal using MRI

    International Nuclear Information System (INIS)

    Niemelaeinen, R.; Videman, T.; Dhillon, S.S.; Battie, M.C.

    2008-01-01

    Aim: To investigate the spinal cord as an alternative intra-body reference to cerebrospinal fluid (CSF) in evaluating thoracic disc signal intensity. Materials and methods: T2-weighted magnetic resonance imaging (MRI) images of T6-T12 were obtained using 1.5 T machines for a population-based sample of 523 men aged 35-70 years. Quantitative data on the signal intensities were acquired using an image analysis program (SpEx (copy right) ). A random sample of 30 subjects and intraclass correlation coeffcients (ICC) were used to examine the repeatability of the spinal cord measurements. The validity of using the spinal cord as a reference was examined by correlating cord and CSF samples. Finally, thoracic disc signal was validated by correlating it with age without adjustment and adjusting for either cord or CSF. Pearson's r was used for correlational analyses. Results: The repeatability of the spinal cord signal measurements was extremely high (≥0.99). The correlations between the signals of spinal cord and CSF by level were all above 0.9. The spinal cord-adjusted disc signal and age correlated similarly with CSF-adjusted disc signal and age (r = -0.30 to -0.40 versus r = -0.26 to -0.36). Conclusion: Adjacent spinal cord is a good alternative reference to the current reference standard, CSF, for quantitative measurements of disc signal intensity. Clearly fewer levels were excluded when using spinal cord as compared to CSF due to missing reference samples

  7. Quantitative measurement of intervertebral disc signal using MRI

    Energy Technology Data Exchange (ETDEWEB)

    Niemelaeinen, R. [Faculty of Rehabilitation Medicine, University of Alberta, Edmonton (Canada)], E-mail: riikka.niemelainen@ualberta.ca; Videman, T. [Faculty of Rehabilitation Medicine, University of Alberta, Edmonton (Canada); Dhillon, S.S. [Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton (Canada); Battie, M.C. [Faculty of Rehabilitation Medicine, University of Alberta, Edmonton (Canada)

    2008-03-15

    Aim: To investigate the spinal cord as an alternative intra-body reference to cerebrospinal fluid (CSF) in evaluating thoracic disc signal intensity. Materials and methods: T2-weighted magnetic resonance imaging (MRI) images of T6-T12 were obtained using 1.5 T machines for a population-based sample of 523 men aged 35-70 years. Quantitative data on the signal intensities were acquired using an image analysis program (SpEx (copy right) ). A random sample of 30 subjects and intraclass correlation coeffcients (ICC) were used to examine the repeatability of the spinal cord measurements. The validity of using the spinal cord as a reference was examined by correlating cord and CSF samples. Finally, thoracic disc signal was validated by correlating it with age without adjustment and adjusting for either cord or CSF. Pearson's r was used for correlational analyses. Results: The repeatability of the spinal cord signal measurements was extremely high ({>=}0.99). The correlations between the signals of spinal cord and CSF by level were all above 0.9. The spinal cord-adjusted disc signal and age correlated similarly with CSF-adjusted disc signal and age (r = -0.30 to -0.40 versus r = -0.26 to -0.36). Conclusion: Adjacent spinal cord is a good alternative reference to the current reference standard, CSF, for quantitative measurements of disc signal intensity. Clearly fewer levels were excluded when using spinal cord as compared to CSF due to missing reference samples.

  8. Functional Connectivity of Resting Hemodynamic Signals in Submillimeter Orientation Columns of the Visual Cortex.

    Science.gov (United States)

    Vasireddi, Anil K; Vazquez, Alberto L; Whitney, David E; Fukuda, Mitsuhiro; Kim, Seong-Gi

    2016-09-07

    Resting-state functional magnetic resonance imaging has been increasingly used for examining connectivity across brain regions. The spatial scale by which hemodynamic imaging can resolve functional connections at rest remains unknown. To examine this issue, deoxyhemoglobin-weighted intrinsic optical imaging data were acquired from the visual cortex of lightly anesthetized ferrets. The neural activity of orientation domains, which span a distance of 0.7-0.8 mm, has been shown to be correlated during evoked activity and at rest. We performed separate analyses to assess the degree to which the spatial and temporal characteristics of spontaneous hemodynamic signals depend on the known functional organization of orientation columns. As a control, artificial orientation column maps were generated. Spatially, resting hemodynamic patterns showed a higher spatial resemblance to iso-orientation maps than artificially generated maps. Temporally, a correlation analysis was used to establish whether iso-orientation domains are more correlated than orthogonal orientation domains. After accounting for a significant decrease in correlation as a function of distance, a small but significant temporal correlation between iso-orientation domains was found, which decreased with increasing difference in orientation preference. This dependence was abolished when using artificially synthetized orientation maps. Finally, the temporal correlation coefficient as a function of orientation difference at rest showed a correspondence with that calculated during visual stimulation suggesting that the strength of resting connectivity is related to the strength of the visual stimulation response. Our results suggest that temporal coherence of hemodynamic signals measured by optical imaging of intrinsic signals exists at a submillimeter columnar scale in resting state.

  9. Modelling and Analysis of Biochemical Signalling Pathway Cross-talk

    Directory of Open Access Journals (Sweden)

    Robin Donaldson

    2010-02-01

    Full Text Available Signalling pathways are abstractions that help life scientists structure the coordination of cellular activity. Cross-talk between pathways accounts for many of the complex behaviours exhibited by signalling pathways and is often critical in producing the correct signal-response relationship. Formal models of signalling pathways and cross-talk in particular can aid understanding and drive experimentation. We define an approach to modelling based on the concept that a pathway is the (synchronising parallel composition of instances of generic modules (with internal and external labels. Pathways are then composed by (synchronising parallel composition and renaming; different types of cross-talk result from different combinations of synchronisation and renaming. We define a number of generic modules in PRISM and five types of cross-talk: signal flow, substrate availability, receptor function, gene expression and intracellular communication. We show that Continuous Stochastic Logic properties can both detect and distinguish the types of cross-talk. The approach is illustrated with small examples and an analysis of the cross-talk between the TGF-b/BMP, WNT and MAPK pathways.

  10. Crustal concealing of small-scale core-field secular variation

    DEFF Research Database (Denmark)

    Hulot, G.; Olsen, Nils; Thebault, E.

    2009-01-01

    of internal origin happen to be detectable now in spherical harmonic degrees up to, perhaps, 16. All of these changes are usually attributed to changes in the core field itself, the secular variation, on the ground that the lithospheric magnetization cannot produce such signals. It has, however, been pointed...... out, on empirical grounds, that temporal changes in the field of internal origin produced by the induced part of the lithospheric magnetization could dominate the core field signal beyond degree 22. This short note revisits this issue by taking advantage of our improved knowledge of the small...... cause of the observed changes in the field of internal origin up to some critical degree, N-C, is indeed likely to be the secular variation of the core field, but that the signal produced by the time-varying lithospheric field is bound to dominate and conceal the time-varying core signal beyond...

  11. Curcumin blocks interleukin-1 signaling in chondrosarcoma cells.

    Directory of Open Access Journals (Sweden)

    Thomas Kalinski

    Full Text Available Interleukin (IL-1 signaling plays an important role in inflammatory processes, but also in malignant processes. The essential downstream event in IL-1 signaling is the activation of nuclear factor (NF-κB, which leads to the expression of several genes that are involved in cell proliferation, invasion, angiogenesis and metastasis, among them VEGF-A. As microenvironment-derived IL-1β is required for invasion and angiogenesis in malignant tumors, also in chondrosarcomas, we investigated IL-1β-induced signal transduction and VEGF-A expression in C3842 and SW1353 chondrosarcoma cells. We additionally performed in vitro angiogenesis assays and NF-κB-related gene expression analyses. Curcumin is a substance which inhibits IL-1 signaling very early by preventing the recruitment of IL-1 receptor associated kinase (IRAK to the IL-1 receptor. We demonstrate that IL-1 signaling and VEGF-A expression are blocked by Curcumin in chondrosarcoma cells. We further show that Curcumin blocks IL-1β-induced angiogenesis and NF-κB-related gene expression. We suppose that IL-1 blockade is an additional treatment option in chondrosarcoma, either by Curcumin, its derivatives or other IL-1 blocking agents.

  12. Search for dark matter effects on gravitational signals from neutron star mergers

    Science.gov (United States)

    Ellis, John; Hektor, Andi; Hütsi, Gert; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

    2018-06-01

    Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.

  13. Search for dark matter effects on gravitational signals from neutron star mergers

    OpenAIRE

    Ellis, John; Hektor, Andi; Hütsi, Gert; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

    2018-01-01

    Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.

  14. Si/SiC-based DD hetero-structure IMPATTs as MM-wave power-source: a generalized large-signal analysis

    International Nuclear Information System (INIS)

    Mukherjee, Moumita; Tripathy, P. R.; Pati, S. P.

    2015-01-01

    A full-scale, self-consistent, non-linear, large-signal model of double-drift hetero-structure IMPATT diode with general doping profile is derived. This newly developed model, for the first time, has been used to analyze the large-signal characteristics of hexagonal SiC-based double-drift IMPATT diode. Considering the fabrication feasibility, the authors have studied the large-signal characteristics of Si/SiC-based hetero-structure devices. Under small-voltage modulation (∼ 2%, i.e. small-signal conditions) results are in good agreement with calculations done using a linearised small-signal model. The large-signal values of the diode's negative conductance (5 × 10 6 S/m 2 ), susceptance (10.4 × 10 7 S/m 2 ), average breakdown voltage (207.6 V), and power generating efficiency (15%, RF power: 25.0 W at 94 GHz) are obtained as a function of oscillation amplitude (50% of DC breakdown voltage) for a fixed average current density. The large-signal calculations exhibit power and efficiency saturation for large-signal (> 50%) voltage modulation and thereafter decrease gradually with further increasing voltage-modulation. This generalized large-signal formulation is applicable for all types of IMPATT structures with distributed and narrow avalanche zones. The simulator is made more realistic by incorporating the space-charge effects, realistic field and temperature dependent material parameters in Si and SiC. The electric field snap-shots and the large-signal impedance and admittance of the diode with current excitation are expressed in closed loop form. This study will act as a guide for researchers to fabricate a high-power Si/SiC-based IMPATT for possible application in high-power MM-wave communication systems. (paper)

  15. Phosphoproteomic Analysis Identifies Signaling Pathways Regulated by Curcumin in Human Colon Cancer Cells.

    Science.gov (United States)

    Sato, Tatsuhiro; Higuchi, Yutaka; Shibagaki, Yoshio; Hattori, Seisuke

    2017-09-01

    Curcumin, a major polyphenol of the spice turmeric, acts as a potent chemopreventive and chemotherapeutic agent in several cancer types, including colon cancer. Although various proteins have been shown to be affected by curcumin, how curcumin exerts its anticancer activity is not fully understood. Phosphoproteomic analyses were performed using SW480 and SW620 human colon cancer cells to identify curcumin-affected signaling pathways. Curcumin inhibited the growth of the two cell lines in a dose-dependent manner. Thirty-nine curcumin-regulated phosphoproteins were identified, five of which are involved in cancer signaling pathways. Detailed analyses revealed that the mTORC1 and p53 signaling pathways are main targets of curcumin. Our results provide insight into the molecular mechanisms of the anticancer activities of curcumin and future molecular targets for its clinical application. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  16. Access to realization of small hydroelectric power station in Republic of Macedonia

    International Nuclear Information System (INIS)

    Jakimova Filipovska, Nevenka

    2001-01-01

    In the paper an overview of the small-scale hydroelectric power plants is presented. The categorization groups of small to micro hydroelectric power plants by different countries are given. Also, the evaluation models of the projects for realization the small hydroelectric power plants are analysed. The aim of the paper is to stress the advantages of the small hydro projects and their implementation in Macedonia

  17. Small-Signal Stability Analysis of Inverter-Fed Power Systems Using Component Connection Method

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2018-01-01

    The small time constants of power electronics devices lead to dynamic couplings with the electromagnetic transients of power networks, and thus complicate the modeling and stability analysis of power-electronics-based power systems. This paper presents a computationally-efficient approach to asse...

  18. Attitude determination for small satellites using GPS signal-to-noise ratio

    Science.gov (United States)

    Peters, Daniel

    An embedded system for GPS-based attitude determination (AD) using signal-to-noise (SNR) measurements was developed for CubeSat applications. The design serves as an evaluation testbed for conducting ground based experiments using various computational methods and antenna types to determine the optimum AD accuracy. Raw GPS data is also stored to non-volatile memory for downloading and post analysis. Two low-power microcontrollers are used for processing and to display information on a graphic screen for real-time performance evaluations. A new parallel inter-processor communication protocol was developed that is faster and uses less power than existing standard protocols. A shorted annular patch (SAP) antenna was fabricated for the initial ground-based AD experiments with the testbed. Static AD estimations with RMS errors in the range of 2.5° to 4.8° were achieved over a range of off-zenith attitudes.

  19. Enhancement of Chiroptical Signals by Circular Differential Mie Scattering of Nanoparticles

    OpenAIRE

    SeokJae Yoo; Q-Han Park

    2015-01-01

    We enhance the weak optical signals of small chiral molecules via circular differential Mie scattering (CDMS) of nanoparticles immersed in them. CDMS is the preferential Mie scattering of left- and right-handed circularly polarized light by nanoparticles whose sizes are about the same as the wavelength of light. Solving the Mie scattering theory for chiral media, we find that the CDMS signal of the particle is linearly proportional to the chirality parameter κ of the molecules. This linear am...

  20. Detecting and identifying small molecules in a nanopore flux capacitor

    International Nuclear Information System (INIS)

    Bearden, Samuel; Zhang, Guigen; McClure, Ethan

    2016-01-01

    A new method of molecular detection in a metallic-semiconductor nanopore was developed and evaluated with experimental and computational methods. Measurements were made of the charging potential of the electrical double layer (EDL) capacitance as charge-carrying small molecules translocated the nanopore. Signals in the charging potential were found to be correlated to the physical properties of analyte molecules. From the measured signals, we were able to distinguish molecules with different valence charge or similar valence charge but different size. The relative magnitude of the signals from different analytes was consistent over a wide range of experimental conditions, suggesting that the detected signals are likely due to single molecules. Computational modeling of the nanopore system indicated that the double layer potential signal may be described in terms of disruption of the EDL structure due to the size and charge of the analyte molecule, in agreement with Huckel and Debye’s analysis of the electrical atmosphere of electrolyte solutions. (paper)

  1. Utilization of Large Scale Surface Models for Detailed Visibility Analyses

    Science.gov (United States)

    Caha, J.; Kačmařík, M.

    2017-11-01

    This article demonstrates utilization of large scale surface models with small spatial resolution and high accuracy, acquired from Unmanned Aerial Vehicle scanning, for visibility analyses. The importance of large scale data for visibility analyses on the local scale, where the detail of the surface model is the most defining factor, is described. The focus is not only the classic Boolean visibility, that is usually determined within GIS, but also on so called extended viewsheds that aims to provide more information about visibility. The case study with examples of visibility analyses was performed on river Opava, near the Ostrava city (Czech Republic). The multiple Boolean viewshed analysis and global horizon viewshed were calculated to determine most prominent features and visibility barriers of the surface. Besides that, the extended viewshed showing angle difference above the local horizon, which describes angular height of the target area above the barrier, is shown. The case study proved that large scale models are appropriate data source for visibility analyses on local level. The discussion summarizes possible future applications and further development directions of visibility analyses.

  2. Bayesian uncertainty analyses of probabilistic risk models

    International Nuclear Information System (INIS)

    Pulkkinen, U.

    1989-01-01

    Applications of Bayesian principles to the uncertainty analyses are discussed in the paper. A short review of the most important uncertainties and their causes is provided. An application of the principle of maximum entropy to the determination of Bayesian prior distributions is described. An approach based on so called probabilistic structures is presented in order to develop a method of quantitative evaluation of modelling uncertainties. The method is applied to a small example case. Ideas for application areas for the proposed method are discussed

  3. Synthesis of digital locomotive receiver of automatic locomotive signaling

    Directory of Open Access Journals (Sweden)

    K. V. Goncharov

    2013-02-01

    Full Text Available Purpose. Automatic locomotive signaling of continuous type with a numeric coding (ALSN has several disadvantages: a small number of signal indications, low noise stability, high inertia and low functional flexibility. Search for new and more advanced methods of signal processing for automatic locomotive signaling, synthesis of the noise proof digital locomotive receiver are essential. Methodology. The proposed algorithm of detection and identification locomotive signaling codes is based on the definition of mutual correlations of received oscillation and reference signals. For selecting threshold levels of decision element the following criterion has been formulated: the locomotive receiver should maximum set the correct solution for a given probability of dangerous errors. Findings. It has been found that the random nature of the ALSN signal amplitude does not affect the detection algorithm. However, the distribution law and numeric characteristics of signal amplitude affect the probability of errors, and should be considered when selecting a threshold levels According to obtained algorithm of detection and identification ALSN signals the digital locomotive receiver has been synthesized. It contains band pass filter, peak limiter, normalizing amplifier with automatic gain control circuit, analog to digital converter and digital signal processor. Originality. The ALSN system is improved by the way of the transfer of technical means to modern microelectronic element base, more perfect methods of detection and identification codes of locomotive signaling are applied. Practical value. Use of digital technology in the construction of the locomotive receiver ALSN will expand its functionality, will increase the noise immunity and operation stability of the locomotive signal system in conditions of various destabilizing factors.

  4. High-resolution small field-of-view magnetic resonance image acquisition system using a small planar coil and a pneumatic manipulator in an open MRI scanner.

    Science.gov (United States)

    Miki, Kohei; Masamune, Ken

    2015-10-01

    Low-field open magnetic resonance imaging (MRI) is frequently used for performing image-guided neurosurgical procedures. Intraoperative magnetic resonance (MR) images are useful for tracking brain shifts and verifying residual tumors. However, it is difficult to precisely determine the boundary of the brain tumors and normal brain tissues because the MR image resolution is low, especially when using a low-field open MRI scanner. To overcome this problem, a high-resolution MR image acquisition system was developed and tested. An MR-compatible manipulator with pneumatic actuators containing an MR signal receiver with a small radiofrequency (RF) coil was developed. The manipulator had five degrees of freedom for position and orientation control of the RF coil. An 8-mm planar RF coil with resistance and inductance of 2.04 [Formula: see text] and 1.00 [Formula: see text] was attached to the MR signal receiver at the distal end of the probe. MR images of phantom test devices were acquired using the MR signal receiver and normal head coil for signal-to-noise ratio (SNR) testing. The SNR of MR images acquired using the MR signal receiver was 8.0 times greater than that of MR images acquired using the normal head coil. The RF coil was moved by the manipulator, and local MR images of a phantom with a 2-mm grid were acquired using the MR signal receiver. A wide field-of-view MR image was generated from a montage of local MR images. A small field-of-view RF system with a pneumatic manipulator was integrated in a low-field MRI scanner to allow acquisition of both wide field-of-view and high-resolution MR images. This system is promising for image-guided neurosurgery as it may allow brain tumors to be observed more clearly and removed precisely.

  5. Engineering satellite-based navigation and timing global navigation satellite systems, signals, and receivers

    CERN Document Server

    Betz, J

    2016-01-01

    This book describes the design and performance analysis of satnav systems, signals, and receivers. It also provides succinct descriptions and comparisons of all the world’s satnav systems. Its comprehensive and logical structure addresses all satnav signals and systems in operation and being developed. Engineering Satellite-Based Navigation and Timing: Global Navigation Satellite Systems, Signals, and Receivers provides the technical foundation for designing and analyzing satnav signals, systems, and receivers. Its contents and structure address all satnav systems and signals: legacy, modernized, and new. It combines qualitative information with detailed techniques and analyses, providing a comprehensive set of insights and engineering tools for this complex multidisciplinary field. Part I describes system and signal engineering including orbital mechanics and constellation design, signal design principles and underlying considerations, link budgets, qua tifying receiver performance in interference, and e...

  6. Transcriptome and Small RNAome Dynamics during a Resistant and Susceptible Interaction between Cucumber and Downy Mildew

    Directory of Open Access Journals (Sweden)

    Alyssa Burkhardt

    2016-03-01

    Full Text Available Cucumber ( L. downy mildew, caused by the obligate oomycete pathogen (Berk. and Curt. Rostov., is the primary factor limiting cucumber production. Although sources of resistance have been identified, such as plant introduction line PI 197088, the genes and processes involved in mediating resistance are still unknown. In the current study, we conducted a comprehensive transcriptome and small RNAome analysis of a resistant (PI 197088 and susceptible (‘Vlaspik’ cucumber during a time course of infection using Illumina sequencing. We identified significantly differentially expressed (DE genes within and between resistant and susceptible cucumber leaves over a time course of infection. Weighted gene correlation network analyses (WGCNA created coexpression modules containing genes with unique expression patterns between Vlaspik and PI 197088. Recurring data trends indicated that resistance to cucumber downy mildew is associated with earlier response to the pathogen, hormone signaling, and regulation of nutrient supply. Candidate resistance genes were identified from multiple transcriptome analyses and literature support. Additionally, parallel sequencing of small RNAs (sRNAs from cucumber and during the infection time course was used to identify and quantify novel and existing microRNA (miRNA in both species. Predicted miRNA targets of cucumber transcripts suggest a complex interconnectedness of gene expression regulation in this plant–pathogen system. This work bioinformatically uncovered gene expression patterns involved in the mediation of or response to resistance. Herein, we provide the foundation for future work to validate candidate resistance genes and miRNA-based regulation proposed in this study.

  7. Archaea Signal Recognition Particle Shows the Way

    Directory of Open Access Journals (Sweden)

    Christian Zwieb

    2010-01-01

    Full Text Available Archaea SRP is composed of an SRP RNA molecule and two bound proteins named SRP19 and SRP54. Regulated by the binding and hydrolysis of guanosine triphosphates, the RNA-bound SRP54 protein transiently associates not only with the hydrophobic signal sequence as it emerges from the ribosomal exit tunnel, but also interacts with the membrane-associated SRP receptor (FtsY. Comparative analyses of the archaea genomes and their SRP component sequences, combined with structural and biochemical data, support a prominent role of the SRP RNA in the assembly and function of the archaea SRP. The 5e motif, which in eukaryotes binds a 72 kilodalton protein, is preserved in most archaea SRP RNAs despite the lack of an archaea SRP72 homolog. The primary function of the 5e region may be to serve as a hinge, strategically positioned between the small and large SRP domain, allowing the elongated SRP to bind simultaneously to distant ribosomal sites. SRP19, required in eukaryotes for initiating SRP assembly, appears to play a subordinate role in the archaea SRP or may be defunct. The N-terminal A region and a novel C-terminal R region of the archaea SRP receptor (FtsY are strikingly diverse or absent even among the members of a taxonomic subgroup.

  8. Statistical optimisation techniques in fatigue signal editing problem

    International Nuclear Information System (INIS)

    Nopiah, Z. M.; Osman, M. H.; Baharin, N.; Abdullah, S.

    2015-01-01

    Success in fatigue signal editing is determined by the level of length reduction without compromising statistical constraints. A great reduction rate can be achieved by removing small amplitude cycles from the recorded signal. The long recorded signal sometimes renders the cycle-to-cycle editing process daunting. This has encouraged researchers to focus on the segment-based approach. This paper discusses joint application of the Running Damage Extraction (RDE) technique and single constrained Genetic Algorithm (GA) in fatigue signal editing optimisation.. In the first section, the RDE technique is used to restructure and summarise the fatigue strain. This technique combines the overlapping window and fatigue strain-life models. It is designed to identify and isolate the fatigue events that exist in the variable amplitude strain data into different segments whereby the retention of statistical parameters and the vibration energy are considered. In the second section, the fatigue data editing problem is formulated as a constrained single optimisation problem that can be solved using GA method. The GA produces the shortest edited fatigue signal by selecting appropriate segments from a pool of labelling segments. Challenges arise due to constraints on the segment selection by deviation level over three signal properties, namely cumulative fatigue damage, root mean square and kurtosis values. Experimental results over several case studies show that the idea of solving fatigue signal editing within a framework of optimisation is effective and automatic, and that the GA is robust for constrained segment selection

  9. Statistical optimisation techniques in fatigue signal editing problem

    Energy Technology Data Exchange (ETDEWEB)

    Nopiah, Z. M.; Osman, M. H. [Fundamental Engineering Studies Unit Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM (Malaysia); Baharin, N.; Abdullah, S. [Department of Mechanical and Materials Engineering Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM (Malaysia)

    2015-02-03

    Success in fatigue signal editing is determined by the level of length reduction without compromising statistical constraints. A great reduction rate can be achieved by removing small amplitude cycles from the recorded signal. The long recorded signal sometimes renders the cycle-to-cycle editing process daunting. This has encouraged researchers to focus on the segment-based approach. This paper discusses joint application of the Running Damage Extraction (RDE) technique and single constrained Genetic Algorithm (GA) in fatigue signal editing optimisation.. In the first section, the RDE technique is used to restructure and summarise the fatigue strain. This technique combines the overlapping window and fatigue strain-life models. It is designed to identify and isolate the fatigue events that exist in the variable amplitude strain data into different segments whereby the retention of statistical parameters and the vibration energy are considered. In the second section, the fatigue data editing problem is formulated as a constrained single optimisation problem that can be solved using GA method. The GA produces the shortest edited fatigue signal by selecting appropriate segments from a pool of labelling segments. Challenges arise due to constraints on the segment selection by deviation level over three signal properties, namely cumulative fatigue damage, root mean square and kurtosis values. Experimental results over several case studies show that the idea of solving fatigue signal editing within a framework of optimisation is effective and automatic, and that the GA is robust for constrained segment selection.

  10. Detection of non-stationary leak signals at NPP primary circuit by cross-correlation analysis

    International Nuclear Information System (INIS)

    Shimanskij, S.B.

    2007-01-01

    A leak-detection system employing high-temperature microphones has been developed for the RBMK and ATR (Japan) reactors. Further improvement of the system focused on using cross-correlation analysis of the spectral components of the signal to detect a small leak at an early stage of development. Since envelope processes are less affected by distortions than are wave processes, they give a higher-degree of correlation and can be used to detect leaks with lower signal-noise ratios. Many simulation tests performed at nuclear power plants have shown that the proposed methods can be used to detect and find the location of a small leak [ru

  11. Jobs, gender and small enterprises in Bangladesh : factors affecting women entrepreneurs in small and cotage industries in Bangladesh

    OpenAIRE

    Karim, Nilufer A

    2001-01-01

    Analyses the constraints faced by women entrepreneurs in Bangladesh, followed by an overview on programmes and projects supporting women entrepreneurs, including training, advice on technology, marketing and financial support. Suggests practical solutions and recommendations that could ease the situation of women in small and cottage industries.

  12. Three-dimensional magnetic nanoparticle imaging using small field gradient and multiple pickup coils

    Energy Technology Data Exchange (ETDEWEB)

    Sasayama, Teruyoshi, E-mail: sasayama@sc.kyushu-u.ac.jp; Tsujita, Yuya; Morishita, Manabu; Muta, Masahiro; Yoshida, Takashi; Enpuku, Keiji

    2017-04-01

    We propose a magnetic particle imaging (MPI) method based on third harmonic signal detection using a small field gradient and multiple pickup coils. First, we developed a system using two pickup coils and performed three-dimensional detection of two magnetic nanoparticle (MNP) samples, which were spaced 15 mm apart. In the experiments, an excitation field strength of 1.6 mT was used at an operating frequency of 3 kHz. A DC gradient field with a typical value of 0.2 T/m was also used to produce the so-called field-free line. A third harmonic signal generated by the MNP samples was detected using the two pickup coils, and the samples were then mechanically scanned to obtain field maps. The field maps were subsequently analyzed using the nonnegative least squares method to obtain three-dimensional position information for the MNP samples. The results show that the positions of the two MNP samples were estimated with good accuracy, despite the small field gradient used. Further improvement in MPI performance will be achieved by increasing the number of pickup coils used. - Highlights: • 3D magnetic particle imaging system combining field-free line and two pickup coils. • Imaging method based on third harmonic signal detection and small field gradient. • Nonnegative least squares method for 3D magnetic nanoparticle image reconstruction. • High spatial resolution despite use of small field gradient.

  13. Can trial sequential monitoring boundaries reduce spurious inferences from meta-analyses?

    DEFF Research Database (Denmark)

    Thorlund, Kristian; Devereaux, P J; Wetterslev, Jørn

    2008-01-01

    BACKGROUND: Results from apparently conclusive meta-analyses may be false. A limited number of events from a few small trials and the associated random error may be under-recognized sources of spurious findings. The information size (IS, i.e. number of participants) required for a reliable......-analyses after each included trial and evaluated their results using a conventional statistical criterion (alpha = 0.05) and two-sided Lan-DeMets monitoring boundaries. We examined the proportion of false positive results and important inaccuracies in estimates of treatment effects that resulted from the two...... approaches. RESULTS: Using the random-effects model and final data, 12 of the meta-analyses yielded P > alpha = 0.05, and 21 yielded P alpha = 0.05. The monitoring boundaries eliminated all false positives. Important inaccuracies in estimates were observed in 6 out of 21 meta-analyses using the conventional...

  14. Comparative analysis of chosen transforms in the context of de-noising harmonic signals

    Directory of Open Access Journals (Sweden)

    Artur Zacniewski

    2015-09-01

    Full Text Available In the article, comparison of popular transforms used i.a. in denoising harmonical signals was presented. The division of signals submitted to mathematical analysis was shown and chosen transforms such as Short Time Fourier Transform, Wigner-Ville Distribution, Wavelet Transform and Discrete Cosine Transform were presented. Harmonic signal with white noise added was submitted for research. During research, the parameters of noise were changed to analyze the effects of using particular transform on noised signal. The importance of right choice for transform and its parameters (different for particular kind of transform was shown. Small changes in parameters or different functions used in transform can lead to considerably different results.[b]Keywords[/b]: denoising of harmonical signals, wavelet transform, discrete cosine transform, DCT

  15. Cosmic microwave background observables of small field models of inflation

    International Nuclear Information System (INIS)

    Ben-Dayan, Ido; Brustein, Ram

    2010-01-01

    We construct a class of single small field models of inflation that can predict, contrary to popular wisdom, an observable gravitational wave signal in the cosmic microwave background anisotropies. The spectral index, its running, the tensor to scalar ratio and the number of e-folds can cover all the parameter space currently allowed by cosmological observations. A unique feature of models in this class is their ability to predict a negative spectral index running in accordance with recent cosmic microwave background observations. We discuss the new class of models from an effective field theory perspective and show that if the dimensionless trilinear coupling is small, as required for consistency, then the observed spectral index running implies a high scale of inflation and hence an observable gravitational wave signal. All the models share a distinct prediction of higher power at smaller scales, making them easy targets for detection

  16. Reduce, reuse, recycle - Developmental signals in spinal cord regeneration.

    Science.gov (United States)

    Cardozo, Marcos Julian; Mysiak, Karolina S; Becker, Thomas; Becker, Catherina G

    2017-12-01

    Anamniotes, fishes and amphibians, have the capacity to regenerate spinal cord tissue after injury, generating new neurons that mature and integrate into the spinal circuitry. Elucidating the molecular signals that promote this regeneration is a fundamental question in regeneration research. Model systems, such as salamanders and larval and adult zebrafish are used to analyse successful regeneration. This shows that many developmental signals, such as Notch, Hedgehog (Hh), Bone Morphogenetic Protein (BMP), Wnt, Fibroblast Growth Factor (FGF), Retinoic Acid (RA) and neurotransmitters are redeployed during regeneration and activate resident spinal progenitor cells. Here we compare the roles of these signals in spinal cord development and regeneration of the much larger and fully patterned adult spinal cord. Understanding how developmental signalling systems are reactivated in successfully regenerating species may ultimately lead to ways to reactivate similar systems in mammalian progenitor cells, which do not show neurogenesis after spinal injury. Copyright © 2017. Published by Elsevier Inc.

  17. B cell antigen receptor signaling and internalization are mutually exclusive events.

    Directory of Open Access Journals (Sweden)

    Ping Hou

    2006-07-01

    Full Text Available Engagement of the B cell antigen receptor initiates two concurrent processes, signaling and receptor internalization. While both are required for normal humoral immune responses, the relationship between these two processes is unknown. Herein, we demonstrate that following receptor ligation, a small subpopulation of B cell antigen receptors are inductively phosphorylated and selectively retained at the cell surface where they can serve as scaffolds for the assembly of signaling molecules. In contrast, the larger population of non-phosphorylated receptors is rapidly endocytosed. Each receptor can undergo only one of two mutually exclusive fates because the tyrosine-based motifs that mediate signaling when phosphorylated mediate internalization when not phosphorylated. Mathematical modeling indicates that the observed competition between receptor phosphorylation and internalization enhances signaling responses to low avidity ligands.

  18. Antipersistent dynamics in short time scale variability of self-potential signals

    OpenAIRE

    Cuomo, V.; Lanfredi, M.; Lapenna, V.; Macchiato, M.; Ragosta, M.; Telesca, L.

    2000-01-01

    Time scale properties of self-potential signals are investigated through the analysis of the second order structure function (variogram), a powerful tool to investigate the spatial and temporal variability of observational data. In this work we analyse two sequences of self-potential values measured by means of a geophysical monitoring array located in a seismically active area of Southern Italy. The range of scales investigated goes from a few minutes to several days. It is shown that signal...

  19. Quantification of analytes affected by relevant interfering signals under quality controlled conditions

    International Nuclear Information System (INIS)

    Bettencourt da Silva, Ricardo J.N.; Santos, Julia R.; Camoes, M. Filomena G.F.C.

    2006-01-01

    The analysis of organic contaminants or residues in biological samples is frequently affected by the presence of compounds producing interfering instrumental signals. This feature is responsible for the higher complexity and cost of these analyses and/or by a significant reduction of the number of studied analytes in a multi-analyte method. This work presents a methodology to estimate the impact of the interfering compounds on the quality of the analysis of complex samples, based on separative instrumental methods of analysis, aiming at supporting the inclusion of analytes affected by interfering compounds in the list of compounds analysed in the studied samples. The proposed methodology involves the study of the magnitude of the signal produced by the interfering compounds in the analysed matrix, and is applicable to analytical systems affected by interfering compounds with varying concentration in the studied matrix. The proposed methodology is based on the comparison of the signals from a representative number of examples of the studied matrix, in order to estimate the impact of the presence of such compounds on the measurement quality. The treatment of the chromatographic signals necessary to collect these data can be easily performed considering algorithms of subtraction of chromatographic signals available in most of the analytical instrumentation software. The subtraction of the interfering compounds signal from the sample signal allows the compensation of the interfering effect irrespective of the relative magnitude of the interfering and analyte signals, supporting the applicability of the same model of the method performance for a broader concentration range. The quantification of the measurement uncertainty was performed using the differential approach, which allows the estimation of the contribution of the presence of the interfering compounds to the quality of the measurement. The proposed methodology was successfully applied to the analysis of

  20. Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)

    Energy Technology Data Exchange (ETDEWEB)

    Hura, Greg L.; Menon, Angeli L.; Hammel, Michal; Rambo, Robert P.; Poole II, Farris L.; Tsutakawa, Susan E.; Jenney Jr, Francis E.; Classen, Scott; Frankel, Kenneth A.; Hopkins, Robert C.; Yang, Sungjae; Scott, Joseph W.; Dillard, Bret D.; Adams, Michael W. W.; Tainer, John A.

    2009-07-20

    We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes for 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.

  1. A Review of Sparsity-Based Methods for Analysing Radar Returns from Helicopter Rotor Blades

    Science.gov (United States)

    2016-09-01

    performance study of these algorithms in the particular problem of analysing backscatter signals from rotating blades. The report is organised as follows...provide further insight into the behaviour of the techniques. Here, the algorithms for MP, OMP, CGP, gOMP and ROMP terminate when 10 atoms are

  2. Signal processing for distributed readout using TESs

    International Nuclear Information System (INIS)

    Smith, Stephen J.; Whitford, Chris H.; Fraser, George W.

    2006-01-01

    We describe optimal filtering algorithms for determining energy and position resolution in position-sensitive Transition Edge Sensor (TES) Distributed Read-Out Imaging Devices (DROIDs). Improved algorithms, developed using a small-signal finite-element model, are based on least-squares minimisation of the total noise power in the correlated dual TES DROID. Through numerical simulations we show that significant improvements in energy and position resolution are theoretically possible over existing methods

  3. Nanobody-Based Biologics for Modulating Purinergic Signaling in Inflammation and Immunity

    Directory of Open Access Journals (Sweden)

    Stephan Menzel

    2018-03-01

    Full Text Available Adenosine triphosphate (ATP and nicotinamide adenine dinucleotide (NAD+ are released as danger signals from cells during infection and sterile inflammation. In the extracellular compartment ATP is converted by CD39, CD73, and other ecto-enzymes into metabolites that modulate the activity of T cells and macrophages. While ATP mediates pro-inflammatory signals via P2X7 and other P2 receptors, adenosine triggers anti-inflammatory signaling via the adenosine 2a receptor (Adora2a and other P1 receptors. The latter also plays a role in maintaining an immunosuppressive tumor microenvironment. NAD+ is converted by CD38, CD203 and other ecto-enzymes to the Ca2+ mobilizing messengers cyclic ADP-ribose and ADP-ribose, and to adenosine. Recent findings on the roles of CD38, CD39, CD73, CD203, P2X7, and Adora2a in inflammation and immunity underscore the potential of these proteins as drug targets. However, available small molecule inhibitors often lack specificity and mediate unwanted off-target toxicity. Nanobodies – single domain antibodies derived from heavy chain antibodies that naturally occur in camelids – display a propensity to bind functional epitopes not accessible to conventional antibodies. Like conventional antibodies, nanobodies and nanobody-based biologics are highly specific and have well-understood, tunable in vivo pharmacodynamics with little if any toxicity. Nanobodies thus represent attractive alternatives to small molecule inhibitors for modulating purinergic signaling in inflammation and immunity. Here we review recent progress made in developing nanobodies against key targets of purinergic signaling.

  4. Nanobody-Based Biologics for Modulating Purinergic Signaling in Inflammation and Immunity.

    Science.gov (United States)

    Menzel, Stephan; Schwarz, Nicole; Haag, Friedrich; Koch-Nolte, Friedrich

    2018-01-01

    Adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide (NAD + ) are released as danger signals from cells during infection and sterile inflammation. In the extracellular compartment ATP is converted by CD39, CD73, and other ecto-enzymes into metabolites that modulate the activity of T cells and macrophages. While ATP mediates pro-inflammatory signals via P2X7 and other P2 receptors, adenosine triggers anti-inflammatory signaling via the adenosine 2a receptor (Adora2a) and other P1 receptors. The latter also plays a role in maintaining an immunosuppressive tumor microenvironment. NAD + is converted by CD38, CD203 and other ecto-enzymes to the Ca 2+ mobilizing messengers cyclic ADP-ribose and ADP-ribose, and to adenosine. Recent findings on the roles of CD38, CD39, CD73, CD203, P2X7, and Adora2a in inflammation and immunity underscore the potential of these proteins as drug targets. However, available small molecule inhibitors often lack specificity and mediate unwanted off-target toxicity. Nanobodies - single domain antibodies derived from heavy chain antibodies that naturally occur in camelids - display a propensity to bind functional epitopes not accessible to conventional antibodies. Like conventional antibodies, nanobodies and nanobody-based biologics are highly specific and have well-understood, tunable in vivo pharmacodynamics with little if any toxicity. Nanobodies thus represent attractive alternatives to small molecule inhibitors for modulating purinergic signaling in inflammation and immunity. Here we review recent progress made in developing nanobodies against key targets of purinergic signaling.

  5. 14C-analyses of calcite coatings in open fractures from the Klipperaas study site, Southern Sweden

    International Nuclear Information System (INIS)

    Possnert, G.; Tullborg, E.L.

    1989-11-01

    Carbonate samples from open fractures in crystalline rock from the Klipperaas study site have been analysed for their 14 C contents using accelerator mass spectrometry. This technique makes it possible to analyse very small carbonate samples (c. 1 mg C). The analyses show low but varying contents of 14 C. However, contamination by CO 2 have taken place affecting small samples more than others. Attempts have been made to quantify the contamination and thus evaluate the analyses of the fracture samples. The obtained low 14 C values can be due to: 1. An effective retention of 14 C by sorption/fractionation forcing 14 C onto the calcite surfaces in the near-surface zone which means that the 14 C contribution to the deeper levels is diminished or 2. the penetration depth of surface groundwater is very shallow. The former is suggested as more probable based on evaluations of the hydrochemical conditions and the fracture mineral studies. (10 figs., 3 tabs., 9 refs.) (authors)

  6. Effects of spike-time-dependent plasticity on the stochastic resonance of small-world neuronal networks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Haitao; Guo, Xinmeng; Wang, Jiang, E-mail: jiangwang@tju.edu.cn; Deng, Bin; Wei, Xile [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)

    2014-09-01

    The phenomenon of stochastic resonance in Newman-Watts small-world neuronal networks is investigated when the strength of synaptic connections between neurons is adaptively adjusted by spike-time-dependent plasticity (STDP). It is shown that irrespective of the synaptic connectivity is fixed or adaptive, the phenomenon of stochastic resonance occurs. The efficiency of network stochastic resonance can be largely enhanced by STDP in the coupling process. Particularly, the resonance for adaptive coupling can reach a much larger value than that for fixed one when the noise intensity is small or intermediate. STDP with dominant depression and small temporal window ratio is more efficient for the transmission of weak external signal in small-world neuronal networks. In addition, we demonstrate that the effect of stochastic resonance can be further improved via fine-tuning of the average coupling strength of the adaptive network. Furthermore, the small-world topology can significantly affect stochastic resonance of excitable neuronal networks. It is found that there exists an optimal probability of adding links by which the noise-induced transmission of weak periodic signal peaks.

  7. Effects of spike-time-dependent plasticity on the stochastic resonance of small-world neuronal networks

    International Nuclear Information System (INIS)

    Yu, Haitao; Guo, Xinmeng; Wang, Jiang; Deng, Bin; Wei, Xile

    2014-01-01

    The phenomenon of stochastic resonance in Newman-Watts small-world neuronal networks is investigated when the strength of synaptic connections between neurons is adaptively adjusted by spike-time-dependent plasticity (STDP). It is shown that irrespective of the synaptic connectivity is fixed or adaptive, the phenomenon of stochastic resonance occurs. The efficiency of network stochastic resonance can be largely enhanced by STDP in the coupling process. Particularly, the resonance for adaptive coupling can reach a much larger value than that for fixed one when the noise intensity is small or intermediate. STDP with dominant depression and small temporal window ratio is more efficient for the transmission of weak external signal in small-world neuronal networks. In addition, we demonstrate that the effect of stochastic resonance can be further improved via fine-tuning of the average coupling strength of the adaptive network. Furthermore, the small-world topology can significantly affect stochastic resonance of excitable neuronal networks. It is found that there exists an optimal probability of adding links by which the noise-induced transmission of weak periodic signal peaks

  8. A small diffusible signal molecule is responsible for the global control of virulence and exoenzyme production in the plant pathogen Erwinia carotovora.

    Science.gov (United States)

    Pirhonen, M; Flego, D; Heikinheimo, R; Palva, E T

    1993-06-01

    Virulence of the plant pathogen Erwinia carotovora subsp. carotovora is dependent on the production and secretion of a complex arsenal of plant cell wall-degrading enzymes. Production of these exoenzymes is controlled by a global regulatory mechanism. A virulent mutants in one of the regulatory loci, expI, show a pleiotropic defect in the growth phase-dependent transcriptional activation of exoenzyme gene expression. The expI gene encodes a 26 kDa polypeptide that is structurally and functionally related to the luxI gene product of Vibrio fischeri. Functional similarity of expI and luxI has been demonstrated by reciprocal genetic complementation experiments. LuxI controls bioluminescence in V.fischeri in a growth phase-dependent manner by directing the synthesis of the diffusible autoinducer, N-(3-oxohexanoyl) homoserine lactone. E.c. subsp. carotovora expI+ strains or Escherichia coli harboring the cloned expI gene excrete a small diffusible signal molecule that complements the expI mutation of Erwinia as well as a luxI mutation of V.fischeri. This extracellular complementation can also be achieved by E.coli harboring the luxI gene from V.fischeri or by adding the synthetic V.fischeri autoinducer. Both the production of the plant tissue-macerating exoenzymes and the ability of the bacteria to propagate in planta are restored in expI mutants by autoinducer addition. These data suggest that the same signal molecule is employed in control of such diverse processes as virulence in a plant pathogen and bioluminescence in a marine bacterium, and may represent a general mechanism by which bacteria modulate gene expression in response to changing environmental conditions.

  9. A multi-dimensional sampling method for locating small scatterers

    International Nuclear Information System (INIS)

    Song, Rencheng; Zhong, Yu; Chen, Xudong

    2012-01-01

    A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method. (paper)

  10. Three WRKY transcription factors additively repress abscisic acid and gibberellin signaling in aleurone cells.

    Science.gov (United States)

    Zhang, Liyuan; Gu, Lingkun; Ringler, Patricia; Smith, Stanley; Rushton, Paul J; Shen, Qingxi J

    2015-07-01

    Members of the WRKY transcription factor superfamily are essential for the regulation of many plant pathways. Functional redundancy due to duplications of WRKY transcription factors, however, complicates genetic analysis by allowing single-mutant plants to maintain wild-type phenotypes. Our analyses indicate that three group I WRKY genes, OsWRKY24, -53, and -70, act in a partially redundant manner. All three showed characteristics of typical WRKY transcription factors: each localized to nuclei and yeast one-hybrid assays indicated that they all bind to W-boxes, including those present in their own promoters. Quantitative real time-PCR (qRT-PCR) analyses indicated that the expression levels of the three WRKY genes varied in the different tissues tested. Particle bombardment-mediated transient expression analyses indicated that all three genes repress the GA and ABA signaling in a dosage-dependent manner. Combination of all three WRKY genes showed additive antagonism of ABA and GA signaling. These results suggest that these WRKY proteins function as negative transcriptional regulators of GA and ABA signaling. However, different combinations of these WRKY genes can lead to varied strengths in suppression of their targets. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  11. A small molecule inhibitor of signal peptide peptidase inhibits Plasmodium development in the liver and decreases malaria severity.

    Directory of Open Access Journals (Sweden)

    Iana Parvanova

    Full Text Available The liver stage of Plasmodium's life cycle is the first, obligatory step in malaria infection. Decreasing the hepatic burden of Plasmodium infection decreases the severity of disease and constitutes a promising strategy for malaria prophylaxis. The efficacy of the gamma-secretase and signal peptide peptidase inhibitor LY411,575 in targeting Plasmodium liver stages was evaluated both in human hepatoma cell lines and in mouse primary hepatocytes. LY411,575 was found to prevent Plasmodium's normal development in the liver, with an IC(50 of approximately 80 nM, without affecting hepatocyte invasion by the parasite. In vivo results with a rodent model of malaria showed that LY411,575 decreases the parasite load in the liver and increases by 55% the resistance of mice to cerebral malaria, one of the most severe malaria-associated syndromes. Our data show that LY411,575 does not exert its effect via the Notch signaling pathway suggesting that it may interfere with Plasmodium development through an inhibition of the parasite's signal peptide peptidase. We therefore propose that selective signal peptide peptidase inhibitors could be potentially used for preventive treatment of malaria in humans.

  12. Analysis of small biomolecules and xenobiotic metabolism using converted graphene-like monolayer plates and laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Kang, Hyunook; Yun, Hoyeol; Lee, Sang Wook; Yeo, Woon-Seok

    2017-06-01

    We report a method of small molecule analysis using a converted graphene-like monolayer (CGM) plate and laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) without organic matrices. The CGM plate was prepared from self-assembled monolayers of biphenyl-4-thiol on gold using electron beam irradiation followed by an annealing step. The above plate was utilized for the LDI-TOF MS analyses of various small molecules and their mixtures, e.g., amino acids, sugars, fatty acids, oligoethylene glycols, and flavonoids. The CGM plate afforded high signal-to-noise ratios, good limits of detection (1pmol to 10fmol), and reusability for up to 30 cycles. As a practical application, the enzymatic activity of the cytochrome P450 2A6 (CYP2A6) enzyme in human liver microsomes was assessed in the 7-hydroxylation of coumarin using the CGM plate without other purification steps. We believe that the prepared CGM plate can be practically used with the advantages of simplicity, sensitivity, and reusability for the matrix-free analysis of small biomolecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Measurement and numerical simulation of a small centrifugal compressor characteristics at small or negative flow rate

    Science.gov (United States)

    Tsukamoto, Kaname; Okada, Mizuki; Inokuchi, Yuzo; Yamasaki, Nobuhiko; Yamagata, Akihiro

    2017-04-01

    For centrifugal compressors used in automotive turbochargers, the extension of the surge margin is demanded because of lower engine speed. In order to estimate the surge line exactly, it is required to acquire the compressor characteristics at small or negative flow rate. In this paper, measurement and numerical simulation of the characteristics at small or negative flow rate are carried out. In the measurement, an experimental facility with a valve immediately downstream of the compressor is used to suppress the surge. In the numerical work, a new boundary condition that specifies mass flow rate at the outlet boundary is used to simulate the characteristics around the zero flow rate region. Furthermore, flow field analyses at small or negative flow rate are performed with the numerical results. The separated and re-circulated flow fields are investigated by visualization to identify the origin of losses.

  14. Why cellular communication during plant reproduction is particularly mediated by CRP signalling.

    Science.gov (United States)

    Bircheneder, Susanne; Dresselhaus, Thomas

    2016-08-01

    Secreted cysteine-rich peptides (CRPs) represent one of the main classes of signalling peptides in plants. Whereas post-translationally modified small non-CRP peptides (psNCRPs) are mostly involved in signalling events during vegetative development and interactions with the environment, CRPs are overrepresented in reproductive processes including pollen germination and growth, self-incompatibility, gamete activation and fusion as well as seed development. In this opinion paper we compare the involvement of both types of peptides in vegetative and reproductive phases of the plant lifecycle. Besides their conserved cysteine pattern defining structural features, CRPs exhibit hypervariable primary sequences and a rapid evolution rate. As a result, CRPs represent a pool of highly polymorphic signalling peptides involved in species-specific functions during reproduction and thus likely represent key players to trigger speciation in plants by supporting reproductive isolation. In contrast, precursers of psNCRPs are proteolytically processed into small functional domains with high sequence conservation and act in more general processes. We discuss parallels in downstream processes of CRP signalling in both reproduction and defence against pathogenic fungi and alien pollen tubes, with special emphasis on the role of ROS and ion channels. In conclusion we suggest that CRP signalling during reproduction in plants has evolved from ancient defence mechanisms. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  15. Evaluation of signal processing for boiling noise detection. Further analysis of BOR-60 reactor noise data

    International Nuclear Information System (INIS)

    Ledwidge, T.J.; Black, J.L.

    1989-01-01

    The present paper deals with investigations of acoustic signals from a boiling experiment performed on the BOR 60 reactor in the USSR. Signals have been analysed in frequency as well as in time domain. Signal characteristics successfully used to detect the boiling process have been found in time domain. A proposal for in-service boiling monitoring by acoustic means is described. (author). 3 refs, 16 figs

  16. Integrative proteomics and biochemical analyses define Ptc6p as the Saccharomyces cerevisiae pyruvate dehydrogenase phosphatase.

    Science.gov (United States)

    Guo, Xiao; Niemi, Natalie M; Coon, Joshua J; Pagliarini, David J

    2017-07-14

    The pyruvate dehydrogenase complex (PDC) is the primary metabolic checkpoint connecting glycolysis and mitochondrial oxidative phosphorylation and is important for maintaining cellular and organismal glucose homeostasis. Phosphorylation of the PDC E1 subunit was identified as a key inhibitory modification in bovine tissue ∼50 years ago, and this regulatory process is now known to be conserved throughout evolution. Although Saccharomyces cerevisiae is a pervasive model organism for investigating cellular metabolism and its regulation by signaling processes, the phosphatase(s) responsible for activating the PDC in S. cerevisiae has not been conclusively defined. Here, using comparative mitochondrial phosphoproteomics, analyses of protein-protein interactions by affinity enrichment-mass spectrometry, and in vitro biochemistry, we define Ptc6p as the primary PDC phosphatase in S. cerevisiae Our analyses further suggest additional substrates for related S. cerevisiae phosphatases and describe the overall phosphoproteomic changes that accompany mitochondrial respiratory dysfunction. In summary, our quantitative proteomics and biochemical analyses have identified Ptc6p as the primary-and likely sole- S. cerevisiae PDC phosphatase, closing a key knowledge gap about the regulation of yeast mitochondrial metabolism. Our findings highlight the power of integrative omics and biochemical analyses for annotating the functions of poorly characterized signaling proteins. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Signal formation processes in Micromegas detectors and quality control for large size detector construction for the ATLAS new small wheel

    Energy Technology Data Exchange (ETDEWEB)

    Kuger, Fabian

    2017-07-31

    The Micromegas technology is one of the most successful modern gaseous detector concepts and widely utilized in nuclear and particle physics experiments. Twenty years of R and D rendered the technology sufficiently mature to be selected as precision tracking detector for the New Small Wheel (NSW) upgrade of the ATLAS Muon spectrometer. This will be the first large scale application of Micromegas in one of the major LHC experiments. However, many of the fundamental microscopic processes in these gaseous detectors are still not fully understood and studies on several detector aspects, like the micromesh geometry, have never been addressed systematically. The studies on signal formation in Micromegas, presented in the first part of this thesis, focuses on the microscopic signal electron loss mechanisms and the amplification processes in electron gas interaction. Based on a detailed model of detector parameter dependencies, these processes are scrutinized in an iterating comparison between experimental results, theory prediction of the macroscopic observables and process simulation on the microscopic level. Utilizing the specialized detectors developed in the scope of this thesis as well as refined simulation algorithms, an unprecedented level of accuracy in the description of the microscopic processes is reached, deepening the understanding of the fundamental process in gaseous detectors. The second part is dedicated to the challenges arising with the large scale Micromegas production for the ATLAS NSW. A selection of technological choices, partially influenced or determined by the herein presented studies, are discussed alongside a final report on two production related tasks addressing the detectors' core components: For the industrial production of resistive anode PCBs a detailed quality control (QC) and quality assurance (QA) scheme as well as the therefore required testing tools have been developed. In parallel the study on micromesh parameter optimization

  18. Signal formation processes in Micromegas detectors and quality control for large size detector construction for the ATLAS new small wheel

    International Nuclear Information System (INIS)

    Kuger, Fabian

    2017-01-01

    The Micromegas technology is one of the most successful modern gaseous detector concepts and widely utilized in nuclear and particle physics experiments. Twenty years of R and D rendered the technology sufficiently mature to be selected as precision tracking detector for the New Small Wheel (NSW) upgrade of the ATLAS Muon spectrometer. This will be the first large scale application of Micromegas in one of the major LHC experiments. However, many of the fundamental microscopic processes in these gaseous detectors are still not fully understood and studies on several detector aspects, like the micromesh geometry, have never been addressed systematically. The studies on signal formation in Micromegas, presented in the first part of this thesis, focuses on the microscopic signal electron loss mechanisms and the amplification processes in electron gas interaction. Based on a detailed model of detector parameter dependencies, these processes are scrutinized in an iterating comparison between experimental results, theory prediction of the macroscopic observables and process simulation on the microscopic level. Utilizing the specialized detectors developed in the scope of this thesis as well as refined simulation algorithms, an unprecedented level of accuracy in the description of the microscopic processes is reached, deepening the understanding of the fundamental process in gaseous detectors. The second part is dedicated to the challenges arising with the large scale Micromegas production for the ATLAS NSW. A selection of technological choices, partially influenced or determined by the herein presented studies, are discussed alongside a final report on two production related tasks addressing the detectors' core components: For the industrial production of resistive anode PCBs a detailed quality control (QC) and quality assurance (QA) scheme as well as the therefore required testing tools have been developed. In parallel the study on micromesh parameter optimization

  19. Thermodynamic and heat transfer analyses for R1234yf and R1234ze(E) as drop-in replacements for R134a in a small power refrigerating system

    International Nuclear Information System (INIS)

    Janković, Zvonimir; Sieres Atienza, Jaime; Martínez Suárez, José Antonio

    2015-01-01

    In this paper we present two different analyses of R1234yf and R1234ze(E) as drop-in replacements for R134a in a small power refrigeration system. The first analysis is based on equal evaporation and condensation temperatures before and after the refrigerant replacement. The second analysis is carried out for equal cooling medium conditions in the condenser, so that the transport properties and the heat transfer features in the condenser are considered for the three refrigerants. In order to perform the analyses, a simulation model was developed, that takes into account specific data, characteristics and dimensions of the main components of a small power refrigeration system. The model was validated with experimental data for R134a and later used to predict the behavior with R1234yf and R1234ze(E). Results show that different conclusions may be drawn if the drop-in analysis is carried out for equal condensation temperatures or for equal temperatures of the cooling medium in the condenser, as well as that these results are affected by the condenser design. In general, R1234yf seems as an adequate drop-in refrigerant for R134a, but R1234ze(E) may perform better when an overridden compressor can be used to match the refrigerating system cooling power. - Highlights: • Low GWP refrigerants R1234yf and R1234ze(E) are potential replacements for R134a. • Refrigerating system mathematical model to predict drop-in performance. • Drop-in analysis for the same evaporation and condensation temperatures. • Drop-in analysis for the same cooling medium temperatures. • Refrigerant heat transfer features have a great impact on the drop-in performance

  20. 18F-FDG PET/CT assessment of histopathologically confirmed mediastinal lymph nodes in non-small cell lung cancer using a penalised likelihood reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Teoh, Eugene J.; Gleeson, Fergus V. [Oxford University Hospitals NHS Foundation Trust, Department of Radiology, Churchill Hospital, Oxford (United Kingdom); University of Oxford, Department of Oncology, Oxford (United Kingdom); McGowan, Daniel R. [University of Oxford, Department of Oncology, Oxford (United Kingdom); Oxford University Hospitals NHS Foundation Trust, Radiation Physics and Protection, Churchill Hospital, Oxford (United Kingdom); Bradley, Kevin M. [Oxford University Hospitals NHS Foundation Trust, Department of Radiology, Churchill Hospital, Oxford (United Kingdom); Belcher, Elizabeth; Black, Edward [Oxford University Hospitals NHS Foundation Trust, Department of Thoracic Surgery, John Radcliffe Hospital, Oxford (United Kingdom); Moore, Alastair; Sykes, Annemarie [Oxford University Hospitals NHS Foundation Trust, Department of Respiratory Medicine, Churchill Hospital, Oxford (United Kingdom)

    2016-11-15

    To investigate whether using a Bayesian penalised likelihood reconstruction (BPL) improves signal-to-background (SBR), signal-to-noise (SNR) and SUV{sub max} when evaluating mediastinal nodal disease in non-small cell lung cancer (NSCLC) compared to ordered subset expectation maximum (OSEM) reconstruction. 18F-FDG PET/CT scans for NSCLC staging in 47 patients (112 nodal stations with histopathological confirmation) were reconstructed using BPL and compared to OSEM. Node and multiple background SUV parameters were analysed semi-quantitatively and visually. Comparing BPL to OSEM, there were significant increases in SUV{sub max} (mean 3.2-4.0, p<0.0001), SBR (mean 2.2-2.6, p<0.0001) and SNR (mean 27.7-40.9, p<0.0001). Mean background SNR on OSEM was 10.4 (range 7.6-14.0), increasing to 12.4 (range 8.2-16.7, p<0.0001). Changes in background SUVs were minimal (largest mean difference 0.17 for liver SUV{sub mean}, p<0.001). There was no significant difference between either algorithm on receiver operating characteristic analysis (p=0.26), although on visual analysis, there was an increase in sensitivity and small decrease in specificity and accuracy on BPL. BPL increases SBR, SNR and SUV{sub max} of mediastinal nodes in NSCLC compared to OSEM, but did not improve the accuracy for determining nodal involvement. (orig.)