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Sample records for cross-relaxation modulates signal

  1. Cross relaxation in nitroxide spin labels

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Cross relaxation, and mI -dependence of the intrinsic electron spin-lattice relaxation rate We , are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We , the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI -dependent.

  2. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    -label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...

  3. Cross-relaxation in multiple pulse NQR spin-locking

    Energy Technology Data Exchange (ETDEWEB)

    Beltjukov, P. A.; Kibrik, G. E. [Perm State University, Physics Department (Russian Federation); Furman, G. B., E-mail: gregoryf@bgu.ac.il; Goren, S. D. [Ben Gurion University, Physics Department (Israel)

    2008-01-15

    The experimental and theoretical NQR multiple-pulse spin locking study of cross-relaxation process in solids containing nuclei of two different sorts I > 1/2 and S = 1/2 coupled by the dipole-dipole interactions and influenced by an external magnetic field. Two coupled equations for the inverse spin temperatures of the both spin systems describing the mutual spin lattice relaxation and the cross-relaxation were obtained using the method of the nonequilibrium state operator. It is shown that the relaxation process is realized with non-exponential time dependence describing by a sum of two exponents. The cross relaxation time is calculated as a function of the multiple-pulse field parameters which agree with the experimental data. The calculated magnetization cross relaxation time vs the strength of the applied magnetic field agrees well with the obtained experimental data.

  4. WAVELET ANALYSIS OF MODULATED SIGNALS

    Institute of Scientific and Technical Information of China (English)

    Hu Jianwei; Yang Shaoquan

    2006-01-01

    The relationship between Haar wavelet decomposition coefficients and modulated signal parameters is discussed. A new modulation classification method is presented. The new method uses the amplitude,frequency and phase information derived from Haar wavelet decomposition as feature vectors to distinguish the modulation types of M-ary Frequency-Shift Keying (MFSK), M-ary Phase-Shift Keying (MPSK) and Quadrature Amplitude Modulation (QAM) modulation types. A parallel combined classifier is designed based on these feature vectors. The overall successful recognition rate of 92.4% can be achieved even at a low Signal-to-Noise Ratio (SNR) of 5dB.

  5. Intracellular signal modulation by nanomaterials.

    Science.gov (United States)

    Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

    2014-01-01

    A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can be of crucial importance for the cytotoxicity of nanomaterials and membrane-dependent signaling pathways have also been shown to be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials, effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future.

  6. Cross Relaxation in rare-earth-doped oxyfluoride glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lakshminarayana, G.; Weis, Eric M. [Materials Science and Technology Division (MST-7), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lira, A.C. [Unidad Académica Profesional Nezahualcóyotl, Universidad Autónoma del Estado de México, Av. Bordo de Xochiaca s/n, Nezahualcóyotl, Estado de Mexico 57000, México (Mexico); Caldiño, Ulises [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, México D.F. 09340 (Mexico); Williams, Darrick J. [Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hehlen, Markus P., E-mail: hehlen@lanl.gov [Materials Science and Technology Division (MST-7), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-07-15

    The excited-state relaxation dynamics of Tb{sup 3+}, Sm{sup 3+}, and Eu{sup 3+} doped into a 50SiO{sub 2}–20Al{sub 2}O{sub 3}–10Na{sub 2}O–20LaF{sub 3} (mol%) oxyfluoride glass are studied. Multiphonon relaxation of the primary emitting states in Tb{sup 3+} ({sup 5}D{sub 3} and {sup 5}D{sub 4}), Sm{sup 3+} ({sup 4}G{sub 5/2}), and Eu{sup 3+} ({sup 5}D{sub 0}) was found to be negligible in the present host. The relaxation of Tb{sup 3+} ({sup 5}D{sub 4}) and Eu{sup 3+} ({sup 5}D{sub 0}) is dominated by radiative decay. For Tb{sup 3+} ({sup 5}D{sub 3}) and Sm{sup 3+} ({sup 4}G{sub 5/2}) in contrast, radiative relaxation is in competition with several non-radiative cross-relaxation processes. This competition was found to be particularly pronounced for the {sup 5}D{sub 3} excited state in Tb{sup 3+}, where a 124-fold decrease of the ({sup 5}D{sub 3}→{sup 7}F{sub 5})/({sup 5}D{sub 4}→{sup 7}F{sub 5}) emission intensity ratio and a ∼10-fold shortening of the {sup 5}D{sub 3} lifetime was observed upon increasing the Tb{sup 3+} concentration from 0.01% to 1%. The Tb{sup 3+} concentration dependence of {sup 5}D{sub 3} also points to some degree of ion aggregation in the “as quenched” glasses. A Judd–Ofelt intensity analysis was performed for Sm{sup 3+} and used to estimate the relative magnitude of {sup 4}G{sub 5/2} cross-relaxation processes. Four cross-relaxation processes in particular were identified to account for 92% of the total {sup 4}G{sub 5/2} non-radiative decay, and a 11% quantum efficiency was estimated for the {sup 4}G{sub 5/2} excited state. Non-exponentiality in the {sup 5}D{sub 0} decay of Eu{sup 3+} is evidence for several Eu{sup 3+} coordination environments in the glass host that manifest in different {sup 5}D{sub 0} decay constants because of the hypersensitivity of the {sup 5}D{sub 0}→{sup 7}F{sub 2} transition. -- Highlights: ► Tb{sup 3+}, Sm{sup 3+}, and Eu{sup 3+} were doped into a LaF{sub 3}-rich oxyfluoride glass. ► The

  7. Automatic modulation recognition of communication signals

    CERN Document Server

    Azzouz, Elsayed Elsayed

    1996-01-01

    Automatic modulation recognition is a rapidly evolving area of signal analysis. In recent years, interest from the academic and military research institutes has focused around the research and development of modulation recognition algorithms. Any communication intelligence (COMINT) system comprises three main blocks: receiver front-end, modulation recogniser and output stage. Considerable work has been done in the area of receiver front-ends. The work at the output stage is concerned with information extraction, recording and exploitation and begins with signal demodulation, that requires accurate knowledge about the signal modulation type. There are, however, two main reasons for knowing the current modulation type of a signal; to preserve the signal information content and to decide upon the suitable counter action, such as jamming. Automatic Modulation Recognition of Communications Signals describes in depth this modulation recognition process. Drawing on several years of research, the authors provide a cr...

  8. Direct current modulation of a photomixing signal

    Science.gov (United States)

    Constantin, Florin L.

    2016-04-01

    Direct modulation of the bias voltage of a LTG-GaAs photomixer is exploited to modulate the signal generated at the frequency of the optical beat between two diode lasers at 820 nm. The photomixing signal is calculated from an expansion in power series of the amplitude of the modulation voltage and displays amplitude modulation sidebands equidistantly spaced to the frequency of the optical beat by integer multiples of the modulation frequency. Modulation at harmonics of the modulation frequency is allowed by the electrical nonlinear response of the photomixer, driven at low voltage by the saturation of the electron drift velocity. Coupling of an alternative voltage to the photomixer operated at zero-bias leads to bifrequency operation. Modulation of the photomixing signal and bifrequency operation of the photomixer are observed experimentally with an optical beat in the microwave regime.

  9. Study on fractal features of modulation signals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on fractal theory, the note presents a novel method of modulation signals classification that adopts box dimension and information dimension extracted from received signals as features of classification. These features contain the characteristics of magnitude, frequency and phase of signals, and collect discriminatory information among various modulation modes. They are effective features in classification sense, and are insensitive to noises interfering. The theoretical analysis also proves the above conclusion. The classifier design is very simple based on such features. The simulation results show that the performances of signal classification are superior.

  10. Amplitude Modulations of Acoustic Communication Signals

    Science.gov (United States)

    Turesson, Hjalmar K.

    2011-12-01

    In human speech, amplitude modulations at 3 -- 8 Hz are important for discrimination and detection. Two different neurophysiological theories have been proposed to explain this effect. The first theory proposes that, as a consequence of neocortical synaptic dynamics, signals that are amplitude modulated at 3 -- 8 Hz are propagated better than un-modulated signals, or signals modulated above 8 Hz. This suggests that neural activity elicited by vocalizations modulated at 3 -- 8 Hz is optimally transmitted, and the vocalizations better discriminated and detected. The second theory proposes that 3 -- 8 Hz amplitude modulations interact with spontaneous neocortical oscillations. Specifically, vocalizations modulated at 3 -- 8 Hz entrain local populations of neurons, which in turn, modulate the amplitude of high frequency gamma oscillations. This suggests that vocalizations modulated at 3 -- 8 Hz should induce stronger cross-frequency coupling. Similar to human speech, we found that macaque monkey vocalizations also are amplitude modulated between 3 and 8 Hz. Humans and macaque monkeys share similarities in vocal production, implying that the auditory systems subserving perception of acoustic communication signals also share similarities. Based on the similarities between human speech and macaque monkey vocalizations, we addressed how amplitude modulated vocalizations are processed in the auditory cortex of macaque monkeys, and what behavioral relevance modulations may have. Recording single neuron activity, as well as, the activity of local populations of neurons allowed us to test both of the neurophysiological theories presented above. We found that single neuron responses to vocalizations amplitude modulated at 3 -- 8 Hz resulted in better stimulus discrimination than vocalizations lacking 3 -- 8 Hz modulations, and that the effect most likely was mediated by synaptic dynamics. In contrast, we failed to find support for the oscillation-based model proposing a

  11. Conversion of phase-modulated signals to amplitude-modulated signals in SOAs due to mirror reflections

    DEFF Research Database (Denmark)

    Blaaberg, Søren; Mørk, Jesper

    2009-01-01

    We present theoretical results that show conversion of phase modulated signals to amplitude modulated signals in an SOA. Large-signal and small-signal calculations show significant conversion responses caused by even minute reflections at the end mirrors.......We present theoretical results that show conversion of phase modulated signals to amplitude modulated signals in an SOA. Large-signal and small-signal calculations show significant conversion responses caused by even minute reflections at the end mirrors....

  12. Cellular Imaging Using Equivalent Cross-Relaxation Rate Technique in Rabbit VX-2 Tumor Model.

    Science.gov (United States)

    Nishiofuku, Hideyuki; Matsushima, Shigeru; Taguchi, Osamu; Inaba, Yoshitaka; Yamaura, Hidekazu; Sato, Yozo; Tanaka, Toshihiro; Kichikawa, Kimihiko

    2011-01-01

    Equivalent cross-relaxation rate (ECR) imaging (ECRI) is a measurement technique that can be used to quantitatively evaluate changes in structural organization and cellular density by MRI. The aim of this study was to evaluate the correlation between the ECR value and cellular density in the rabbit VX2 tumor model. Five rabbits implanted with 10 VX2 tumors in the femur muscles were included in this study. We adopted the off-resonance technique with a single saturation transfer pulse frequency of 7 ppm downfield from water resonance. The ECR value was defined as the percentage of signal loss between the unsaturated and saturated images. ECR images were constructed based on the percentage of the ECR value. Pathological specimens were divided into 34 areas and classified into two groups: the viable group and the necrotic group. ECR values were measured and compared between groups. The correlation between the ECR value and cellular density was then determined. The mean ECR value was significantly higher in the viable group than in the necrotic group (61.2% vs. 35.8%). The area under the curve that calculated by receiver operating characteristic curve was 0.991 at 7 ppm. The regression graph showed a linear relationship between the ECR value and cellular density; the correlation coefficient (r) was 0.858. There is a strong association between the ECR value and cellular density in VX2 tumors and so ECRI could be a potentially useful technique for accurately depicting viable and necrotic areas.

  13. Slow Molecular Motions in Ionic Liquids Probed by Cross-Relaxation of Nuclear Spins During Overhauser Dynamic Nuclear Polarization.

    Science.gov (United States)

    Banerjee, Abhishek; Dey, Arnab; Chandrakumar, Narayanan

    2016-11-14

    Solution-state Overhauser dynamic nuclear polarization (ODNP) at moderate fields, performed by saturating the electron spin resonance (ESR) of a free radical added to the sample of interest, is well known to lead to significant NMR signal enhancements in the steady state, owing to electron-nuclear cross-relaxation. Here it is shown that under conditions which limit radical access to the molecules of interest, the time course of establishment of ODNP can provide a unique window into internuclear cross-relaxation, and reflects relatively slow molecular motions. This behavior, modeled mathematically by a three-spin version of the Solomon equations (one unpaired electron and two nuclear spins), is demonstrated experimentally on the (19) F/(1) H system in ionic liquids. Bulky radicals in these viscous environments turn out to be just the right setting to exploit these effects. Compared to standard nuclear Overhauser effect (NOE) work, the present experiment offers significant improvement in dynamic range and sensitivity, retains usable chemical shift information, and reports on molecular motions in the sub-megahertz (MHz) to tens of MHz range-motions which are not accessed at high fields. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Plant MAPK cascades: Just rapid signaling modules?

    KAUST Repository

    Boudsocq, Marie

    2015-08-27

    © 2015 Taylor & Francis Group, LLC. Abscisic acid (ABA) is a major phytohormone mediating important stress-related processes. We recently unveiled an ABA-activated MAPK signaling module constituted of MAP3K17/18-MKK3-MPK1/2/7/14. Unlike classical rapid MAPK activation, we showed that the activation of the new MAPK module is delayed and relies on the MAP3K protein synthesis. In this addendum, we discuss the role of this original and unexpected activation mechanism of MAPK cascades which suggests that MAPKs can regulate both early and longterm plant stress responses.

  15. Acetylation modulates the STAT signaling code.

    Science.gov (United States)

    Wieczorek, Martin; Ginter, Torsten; Brand, Peter; Heinzel, Thorsten; Krämer, Oliver H

    2012-12-01

    A fascinating question of modern biology is how a limited number of signaling pathways generate biological diversity and crosstalk phenomena in vivo. Well-defined posttranslational modification patterns dictate the functions and interactions of proteins. The signal transducers and activators of transcription (STATs) are physiologically important cytokine-induced transcription factors. They are targeted by a multitude of posttranslational modifications that control and modulate signaling responses and gene expression. Beyond phosphorylation of serine and tyrosine residues, lysine acetylation has recently emerged as a critical modification regulating STAT functions. Interestingly, acetylation can determine STAT signaling codes by various molecular mechanisms, including the modulation of other posttranslational modifications. Here, we provide an overview on the acetylation of STATs and how this protein modification shapes cellular cytokine responses. We summarize recent advances in understanding the impact of STAT acetylation on cell growth, apoptosis, innate immunity, inflammation, and tumorigenesis. Furthermore, we discuss how STAT acetylation can be targeted by small molecules and we consider the possibility that additional molecules controlling STAT signaling are regulated by acetylation. Our review also summarizes evolutionary aspects and we show similarities between the acetylation-dependent control of STATs and other important molecules. We propose the concept that, similar to the 'histone code', distinct posttranslational modifications and their crosstalk orchestrate the functions and interactions of STAT proteins.

  16. Extraocular muscle afferent signals modulate visual attention.

    Science.gov (United States)

    Balslev, Daniela; Newman, William; Knox, Paul C

    2012-10-09

    Extraocular muscle afferent signals contribute to oculomotor control and visual localization. Prompted by the close links between the oculomotor and attention systems, it was investigated whether these proprioceptive signals also modulated the allocation of attention in space. A suction sclera contact lens was used to impose an eye rotation on the nonviewing, dominant eye. With their viewing, nondominant eye, participants (n = 4) fixated centrally and detected targets presented at 5° in the left or right visual hemifield. The position of the viewing eye was monitored throughout the experiment. As a control, visual localization was tested using finger pointing without visual feedback of the hand, whereas the nonviewing eye remained deviated. The sustained passive rotation of the occluded, dominant eye, while the other eye maintained central fixation, resulted in a lateralized change in the detectability of visual targets. In all participants, the advantage in speed and accuracy for detecting right versus left hemifield targets that occurred during a sustained rightward eye rotation of the dominant eye was reduced or reversed by a leftward eye rotation. The control experiment confirmed that the eye deviation procedure caused pointing errors consistent with an approximately 2° shift in perceived eye position, in the direction of rotation of the nonviewing eye. With the caveat of the small number of participants, these results suggest that extraocular muscle afferent signals modulate the deployment of attention in visual space.

  17. Linear Frequency Modulated Signals VS Orthogonal Frequency Division Multiplexing Signals for Synthetic Aperture Radar Systems

    Science.gov (United States)

    2014-06-01

    FREQUENCY MODULATED SIGNALS VS ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SIGNALS FOR SYNTHETIC APERTURE RADAR SYSTEMS by Sade A. Holder June...SIGNALS VS ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SIGNALS FOR SYNTHETIC APERTURE RADAR SYSTEMS 5. FUNDING NUMBERS 6. AUTHOR(S) Sade A. Holder 7...OFDM) signal versus a linear frequency modulated or chirp signal on simulated synthetic aperture radar (SAR) imagery. Various parameters of the

  18. Endocannabinoid Signaling in Modulating Periimplantation Events

    Institute of Scientific and Technical Information of China (English)

    Hong-ying PENG; Qi CHEN; Dong-mei TAN; Yi TAN

    2008-01-01

    Cannabinoids have long been suspected associating with abnormal fetal growth and outcome. However, the molecular mechanisms in which they are involved had long been obscure for several decades. Only recently, after the identification of two types of cannabinoid receptors (CBI-R and CB2-R) and the following discoveries of their corresponding endogenous ligands, the mystery behind those seemingly facts began gradually unveiled. Through a series of landmark research, it is now indicated that the endocannabinoid signaling via the ligand-receptor interaction plays an important role in modulating early development of preimplantation embryo and synchronizing embryo development with uterine receptivity for implantation. Current data suggest that the physiological functions of endocannabinoid signaling as well as their metabolic pathways are potentially very exited areas to be explored further. This review will first introduce the reproductive functions of endocannabinoid signaling from epidemiological and molecular background, then focus on its reciprocal interactions between the embryo and maternal tissues, as well as related metabolic aspects in regards to implantation. It is hoped that further investigation of this physiologically fundamental signaling will generate more exciting information elucidating the complexity of implantation thus lead to a better control of human reproduction.

  19. Auxin signaling modules regulate maize inflorescence architecture.

    Science.gov (United States)

    Galli, Mary; Liu, Qiujie; Moss, Britney L; Malcomber, Simon; Li, Wei; Gaines, Craig; Federici, Silvia; Roshkovan, Jessica; Meeley, Robert; Nemhauser, Jennifer L; Gallavotti, Andrea

    2015-10-27

    In plants, small groups of pluripotent stem cells called axillary meristems are required for the formation of the branches and flowers that eventually establish shoot architecture and drive reproductive success. To ensure the proper formation of new axillary meristems, the specification of boundary regions is required for coordinating their development. We have identified two maize genes, BARREN INFLORESCENCE1 and BARREN INFLORESCENCE4 (BIF1 and BIF4), that regulate the early steps required for inflorescence formation. BIF1 and BIF4 encode AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins, which are key components of the auxin hormone signaling pathway that is essential for organogenesis. Here we show that BIF1 and BIF4 are integral to auxin signaling modules that dynamically regulate the expression of BARREN STALK1 (BA1), a basic helix-loop-helix (bHLH) transcriptional regulator necessary for axillary meristem formation that shows a striking boundary expression pattern. These findings suggest that auxin signaling directly controls boundary domains during axillary meristem formation and define a fundamental mechanism that regulates inflorescence architecture in one of the most widely grown crop species.

  20. New modulator for the optical signal in a fiber

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tian-hao; JIA Feng; WANG Shun-li; MAN Jiang wei; NIU Kai; WANG Xu-cheng; YANG Jia

    2006-01-01

    A new modulator for the optical signal in a fiber based on multi-beam interference is designed. In the experiment,the distance of a couple of abutted fibers was modulated through a piezoelectric ceramic pipe driven by 50 Hz AC voltage, so that the amplitude of the transmitted optical signal was modulated. The modulation ratio is about 10% ,S/N ratio is about 60 dB and the bandwidth is about 200 KHz.

  1. Modulation of neurotrophic signaling pathways by polyphenols.

    Science.gov (United States)

    Moosavi, Fatemeh; Hosseini, Razieh; Saso, Luciano; Firuzi, Omidreza

    2016-01-01

    concomitant modulations of signaling pathways is useful for designing more effective agents for management of neurodegenerative diseases.

  2. Gearbox Vibration Signal Amplitude and Frequency Modulation

    Directory of Open Access Journals (Sweden)

    Fakher Chaari

    2012-01-01

    Full Text Available Gearboxes usually run under fluctuating load conditions during service, however most of papers available in the literature describe models of gearboxes under stationary load conditions. Main task of published papers is fault modeling for their detection. Considering real situation from industry, the assumption of stationarity of load conditions cannot be longer kept. Vibration signals issued from monitoring in maintenance operations differ from mentioned models (due to load non-stationarity and may be difficult to analyze which lead to erroneous diagnosis of the system. The objective of this paper is to study the influence of time varying load conditions on a gearbox dynamic behavior. To investigate this, a simple spur gear system without defects is modeled. It is subjected to a time varying load. The speed-torque characteristic of the driving motor is considered. The load variation induces speed variation, which causes a variation in the gearmesh stiffness period. Computer simulation shows deep amplitude modulations with sidebands that don't differ from those obtained when there is a defective tooth. In order to put in evidence the time varying load effects, Short Time Fourier Transform and then Smoothed Wigner-Ville distribution are used. Results show that the last one is well suited for the studied case.

  3. Electron--electron double resonance study of magnetic energy transfer between trapped electrons and radicals in organic glasses: Relation between dipolar cross relaxation times and dipolar interaction distances

    Energy Technology Data Exchange (ETDEWEB)

    Lin, D.P.; Feng, D.F.; Ngo, F.Q.H.; Kevan, L.

    1976-11-15

    Electron--electron double resonance (ELDOR) has been used to measure cross-relaxation times between trapped electrons and trapped radicals produced by ..gamma.. irradiation of 2-methyltetrahydrofuran and 3-methylhexane organic glasses. The cross-relaxation times are measured as a function of temperature, radiation dose, and the frequency difference ..delta..f of the microwave frequencies used. The cross-relaxation times are nearly temperature independent and depend on ..delta..f/sup 2/ at doses where the spin concentrations approach uniformity; these features indicate the dominance of single step over multistep cross-relaxation processes. Equations have been derived to relate the dipolar cross-relaxation distance to the measured cross-relaxation times, and it is suggested that the cross-relaxation line shape is Lorentzian in magnetically dilute systems. Typical electron--radical correlation distances in these organic glasses are 10 A. (AIP)

  4. Automatic Modulation Recognition of Mixed Multiple Source Signals

    Science.gov (United States)

    Tan, Xiaobo; Zhang, Hang; Lu, Wei

    2011-03-01

    In this paper, automatic modulation recognition of mixed multiple source signals is discussed. At first, the algorithm of equivariant adaptive source separation (EASI) is employed to separate signals from their mixed waveforms. Four features of five modulated signals are extracted and then two classifiers, decision tree and neutral network are used to complete modulation classification. The effects of symbol shaping on features extraction and validation of source separation are also investigated. Simulations show that the average probability of correct recognition of the classifiers is very depended on the performance of source separation. When SNR (Signal to Noise Ratio) is larger than 15 dB and the number of mixed source signals is less than 4, the average probability of correct recognition is above 0.6 for decision tree classifier and 0.63 for neutral network classifier. Simulations and discussions about automatic modulation recognition for source signals surfed Rayleigh flat fading are also presented.

  5. Effect of signal modulating noise in bistable stochastic dynamical systems

    Institute of Scientific and Technical Information of China (English)

    肖方红; 闫桂荣; 张新武

    2003-01-01

    The effect of signal modulating noise in bistable stochastic dynamical systems is studied.The concept of instan taneous steady state is proposed for bistable dynamical systems.By making a dynamical analysis of bistable stochastic systems,we find that global and local effect of signal modulating noise as well as stochastic resonance can occur in bistable dynamical systems on which both a weak sinusoidal signal and noise are forced.The effect is demonstrated by numerical simulation.

  6. Nuclear magnetic relaxation studies of water in frozen biological tissues. Cross-relaxation effects between protein and bound water protons

    Science.gov (United States)

    Escanyé, J. M.; Canet, D.; Robert, J.

    Water proton longitudinal relaxation has been investigated in frozen mouse tissues including tumors. The nonfreezable water which gives rise to a relatively sharp NMR signal at this temperature (263 K) is identified as water bound to macromolecules. Measurements have been carried out by the nonselective inversion-recovery method at 90 and 6 MHz. Partially selective inversion has been achieved at 90 MHz by the DANTE sequence. The experimental data are analyzed by means of Solomon-type equations. This analysis provides the cross-relaxation term from which the dipolar contribution to water relaxation rate, arising from interactions with macromolecular protons, is calculated. This contribution seems to be dominant. The number of water protons interacting with a given macromolecular proton is found to be of the order of 10. The data at both frequencies can be consistently interpreted in terms of water diffusion, with a characteristic time of about 10 -9 sec. These conclusions are valid for all the tissues investigated here, their relaxation parameters exhibiting only slight differences.

  7. Adiabatic fast passage application in solid state NMR study of cross relaxation and molecular dynamics in heteronuclear systems

    Science.gov (United States)

    Baranowski, M.; Woźniak-Braszak, A.; Jurga, K.

    2016-01-01

    The paper presents the benefits of using fast adiabatic passage for the study of molecular dynamics in the solid state heteronuclear systems in the laboratory frame. A homemade pulse spectrometer operating at the frequency of 30.2 MHz and 28.411 MHz for protons and fluorines, respectively, has been enhanced with microcontroller direct digital synthesizer DDS controller [1-4]. This work briefly describes how to construct a low-cost and easy-to-assemble adiabatic extension set for homemade and commercial spectrometers based on recently very popular Arduino shields. The described set was designed for fast adiabatic generation. Timing and synchronization problems are discussed. The cross-relaxation experiments with different initial states of the two spin systems have been performed. Contrary to our previous work [5] where the steady-state NOE experiments were conducted now proton spins 1H are polarized in the magnetic field B0 while fluorine spins 19F are perturbed by selective saturation for a short time and then the system is allowed to evolve for a period in the absence of a saturating field. The adiabatic passage application leads to a reversal of magnetization of fluorine spins and increases the amplitude of the signal.

  8. Decoding a combined amplitude modulated and frequency modulated signal

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to a method for decoding a combined AM/FM encoded signal, comprising the steps of: combining said encoded optical signal with light from a local oscillator configured with a local oscillator frequency; converting the combined local oscillator and encoded optical sig...

  9. Synchronization of chaotic VCSELs by external chaotic signal parameter modulation

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Shenghai Zhang; Xingzhong Qian; Yanbin Wang

    2009-01-01

    Synchronization of chaotic vertical-cavity surface-emitting lasers (VCSELs) is achieved by external chaotic signal modulation successfully.Simulation indicates that we can get chaos synchronization if the intensity of external chaotic signal is large enough.First of all,we use direct current modulation to achieve the chaos of VCSELs,and determine the laser's chaotic state by analyzing time series of the output and the corresponding power spectrum.And then we achieve synchronization of the two chaotic systems by external chaotic signal parameter modulation.We also find that the larger the modulation intensity is,the easier it is to achieve synchronization for chaotic VCSELs.This approach can also be applied to systems with a number of modulated lasers.

  10. Optical signal processing using electro-absorption modulators

    DEFF Research Database (Denmark)

    Mørk, Jesper; Romstad, Francis Pascal; Højfeldt, Sune

    2003-01-01

    Reverse-biased semiconductor waveguides are efficient saturable absorbers and have a number of promising all-optical signal processing applications. Results on ultrafast modulator dynamics as well as demonstrations and investigations of wavelength conversion and regeneration are presented....

  11. 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

  12. Identifying Epigenetic Modulators of Resistance to ERK Signaling Inhibitors

    Science.gov (United States)

    2015-08-01

    AWARD NUMBER: WSlXWH-14-1-0230 TITLE: Identifying Epigenetic Modulators of Resistance to ERK Signaling Inhibitors PRINCIPAL INVESTIGATOR: Emily...5a. CONTRACT NUMBER Identifying Epigenetic Modulators of Resistance to ERK Signaling Inhibitors 5b. GRANT NUMBER W8 1XWH- 1 4 - 1 - 0230 5c...response to targeted therapies in cancer. However, a global and unbiased approach to decipher the epigenetic mechanisms underlying melanoma drug

  13. Signal Constellations for Multilevel Coded Modulation with Sparse Graph Codes

    NARCIS (Netherlands)

    Cronie, Harm S.

    2005-01-01

    A method to combine error-correction coding and spectral efficient modulation for transmission over channels with Gaussian noise is presented. The method of modulation leads to a signal constellation in which the constellation symbols have a nonuniform distribution. This gives a so-called shape gain

  14. Spectral Correlation of Multicarrier Modulated Signals and Its Application for Signal Detection

    Science.gov (United States)

    Zhang, Haijian; Le Ruyet (Eurasipmember), Didier; Terré, Michel

    2009-12-01

    Spectral correlation theory for cyclostationary time-series signals has been studied for decades. Explicit formulas of spectral correlation function for various types of analog-modulated and digital-modulated signals are already derived. In this paper, we investigate and exploit the cyclostationarity characteristics for two kinds of multicarrier modulated (MCM) signals: conventional OFDM and filter bank based multicarrier (FBMC) signals. The spectral correlation characterization of MCM signal can be described by a special linear periodic time-variant (LPTV) system. Using this LPTV description, we have derived the explicit theoretical formulas of nonconjugate and conjugate cyclic autocorrelation function (CAF) and spectral correlation function (SCF) for OFDM and FBMC signals. According to theoretical spectral analysis, Cyclostationary Signatures (CS) are artificially embedded into MCM signal and a low-complexity signature detector is, therefore, presented for detecting MCM signal. Theoretical analysis and simulation results demonstrate the efficiency and robustness of this CS detector compared to traditionary energy detector.

  15. Spectral Correlation of Multicarrier Modulated Signals and Its Application for Signal Detection

    Directory of Open Access Journals (Sweden)

    Zhang Haijian

    2010-01-01

    Full Text Available Spectral correlation theory for cyclostationary time-series signals has been studied for decades. Explicit formulas of spectral correlation function for various types of analog-modulated and digital-modulated signals are already derived. In this paper, we investigate and exploit the cyclostationarity characteristics for two kinds of multicarrier modulated (MCM signals: conventional OFDM and filter bank based multicarrier (FBMC signals. The spectral correlation characterization of MCM signal can be described by a special linear periodic time-variant (LPTV system. Using this LPTV description, we have derived the explicit theoretical formulas of nonconjugate and conjugate cyclic autocorrelation function (CAF and spectral correlation function (SCF for OFDM and FBMC signals. According to theoretical spectral analysis, Cyclostationary Signatures (CS are artificially embedded into MCM signal and a low-complexity signature detector is, therefore, presented for detecting MCM signal. Theoretical analysis and simulation results demonstrate the efficiency and robustness of this CS detector compared to traditionary energy detector.

  16. Uncovering signals from measurement noise by electro mechanical amplitude modulation

    NARCIS (Netherlands)

    Droogendijk, H.; Sanders, Remco G.P.; Krijnen, Gijsbertus J.M.

    2013-01-01

    We present an electromechanical parametric scheme to improve the low-frequency signal-to-noise ratio of energy buffering type transducers. The method is based on periodic modulation of the stiffness in the sensory system which produces upconverted replicas of the signals of interest at frequencies

  17. Automatic Classification of Digitally Modulated Signals.

    Science.gov (United States)

    1987-12-01

    the bandwidth of a sinusoid approaches zero as the observation time becomes infinite ( Stremler ,1982:87). In practice, the bandwith will be small, but...straightforward manner. Detailed explanations of these operations can be found in the references(Couch,1983;Schwartz, 1980; Stremler ,1982). Since the... Stremler ,1982: 279). The variance of its envelope is zero and therefore, R is equal to zero. For amplitude modulation, the information is conveyed by

  18. Digital Monopulse Receivers for Phase Modulated Signals

    Science.gov (United States)

    2005-04-14

    Mateo Burgos-García, Gema Ferreiro-Collar, Alberto Asensio Ló Grupo de Microondas y Dpto. Señales, Sistemas y Radio E.T.S.I. Telecomunic Universidad...Politécnica d Ciudad Universitaria 28040 Madrid, Spa Email: mateo@gmr.ssr. Digital Monopulse Rec Modulated Si T ∆ Σ Z1(t) Z2(t)log-amplifier of each...Microondas y Radar Dpto. Señales, Sistemas y Radiocomunicaciones E.T.S.I. Telecomunicación Universidad Politécnica de Madrid Ciudad Universitaria s/n

  19. Sensor Signal Processing for Ultrasonic Sensors Using Delta-Sigma Modulated Single-Bit Digital Signal

    Science.gov (United States)

    Hirata, S.; Kurosawa, M. K.; Katagiri, T.

    Ultrasonic distance measurement is based on determining the time of flight of ultrasonic wave. The pulse compression technique that obtains the cross-correlation function between the received signal and the reference signal is used to improve the resolution of distance measurement. The cross-correlation method requires high-cost digital signal processing. This paper presents a cross-correlation method using a delta-sigma modulated single-bit digital signal. Sensor signal processing composed of the cross-correlation between two single-bit signals and a post-moving average filter is proposed and enables reducing the cost of digital signal processing.

  20. Electronic modulation of biochemical signal generation

    Science.gov (United States)

    Gordonov, Tanya; Kim, Eunkyoung; Cheng, Yi; Ben-Yoav, Hadar; Ghodssi, Reza; Rubloff, Gary; Yin, Jun-Jie; Payne, Gregory F.; Bentley, William E.

    2014-08-01

    Microelectronic devices that contain biological components are typically used to interrogate biology rather than control biological function. Patterned assemblies of proteins and cells have, however, been used for in vitro metabolic engineering, where coordinated biochemical pathways allow cell metabolism to be characterized and potentially controlled on a chip. Such devices form part of technologies that attempt to recreate animal and human physiological functions on a chip and could be used to revolutionize drug development. These ambitious goals will, however, require new biofabrication methodologies that help connect microelectronics and biological systems and yield new approaches to device assembly and communication. Here, we report the electrically mediated assembly, interrogation and control of a multi-domain fusion protein that produces a bacterial signalling molecule. The biological system can be electrically tuned using a natural redox molecule, and its biochemical response is shown to provide the signalling cues to drive bacterial population behaviour. We show that the biochemical output of the system correlates with the electrical input charge, which suggests that electrical inputs could be used to control complex on-chip biological processes.

  1. Interleaved IIR filter on Δ-Σ modulated signals

    Science.gov (United States)

    Lewis, David M.

    1996-10-01

    This paper describes a circuit implementing 12 fully independent biquad digital filters operating on (Delta) - (Sigma) modulated signals with 28 b resolution. A carry-save adder with partial carry propagation (Delta) -(Sigma) modulator is used together with a pipelined architecture that interleaves all of the filters on a single datapath. Implemented in TSPC logic, the circuit comprises 95 K transistors, including a variable frequency on-chip clock generator.

  2. Response of plasmonic terahertz detectors to amplitude modulated signals

    Science.gov (United States)

    Rupper, Greg; Rudin, Sergey; Shur, Michael

    2015-09-01

    We present theoretical study of the response of two-dimensional gated electron gas to an amplitude modulated signals with carrier frequency in the terahertz range. The model is based on complete hydrodynamic equations, and includes effects of viscosity, pressure gradients and thermal transport in the conduction channel of a high electron mobility semiconductor transistor (HEMT). The modulation response was evaluated as a function of modulation frequency fM for a wide range of mobility values. Maximum modulation frequency fMAX was evaluated as a function of channel mobility, with typical values of fMAX in the subterahertz range of frequencies. Our analysis shows that short channel field effect transistors operating in the plasmonic regime can meet all the requirements for applications as terahertz detectors and modulators in ultra high-speed wireless communication circuits.

  3. Response of Plasmonic Terahertz Detectors to Modulated Signals

    Science.gov (United States)

    Rudin, Sergey; Rupper, Greg; Reed, Meredith; Shur, Michael

    We present theoretical study of the response of two-dimensional gated electron gas to an amplitude modulated signals with carrier frequency in the terahertz range. Our model is based on complete hydrodynamic equations, and includes effects of viscosity, pressure gradients and thermal transport in the conduction channel of a high electron mobility semiconductor transistor. The modulation response was evaluated as a function of modulation frequency for a range of mobility values in different semiconductor materials. Maximum modulation frequency was evaluated as a function of channel mobility, with typical values in the subterahertz range of frequencies. Our analysis shows that short channel field effect transistors operating in the plasmonic regime meets the requirements for applications as terahertz detectors and modulators in high-speed wireless communication circuits.

  4. Semaphorin 6A regulates angiogenesis by modulating VEGF signaling

    OpenAIRE

    Segarra, Marta; Ohnuki, Hidetaka; Maric, Dragan; Salvucci, Ombretta; Hou, Xu; Kumar, Anil; Li, Xuri; Tosato, Giovanna

    2012-01-01

    Formation of new vessels during development and in the mature mammal generally proceeds through angiogenesis. Although a variety of molecules and signaling pathways are known to underlie endothelial cell sprouting and remodeling during angiogenesis, many aspects of this complex process remain unexplained. Here we show that the transmembrane semaphorin6A (Sema6A) is expressed in endothelial cells, and regulates endothelial cell survival and growth by modulating the expression and signaling of ...

  5. Neural Signaling Metabolites May Modulate Energy Use in Hibernation.

    Science.gov (United States)

    Drew, Kelly L; Frare, Carla; Rice, Sarah A

    2017-01-01

    Despite an epidemic in obesity and metabolic syndrome limited means exist to effect adiposity or metabolic rate other than life style changes. Here we review evidence that neural signaling metabolites may modulate thermoregulatory pathways and offer novel means to fine tune energy use. We extend prior reviews on mechanisms that regulate thermogenesis and energy use in hibernation by focusing primarily on the neural signaling metabolites adenosine, AMP and glutamate.

  6. Vitamin D Signaling Modulators in Cancer Therapy.

    Science.gov (United States)

    Luo, Wei; Johnson, Candace S; Trump, Donald L

    2016-01-01

    The antiproliferative and pro-apoptotic effects of 1α,25-dihydroxycholecalciferol (1,25(OH)2D3, 1,25D3, calcitriol) have been demonstrated in various tumor model systems in vitro and in vivo. However, limited antitumor effects of 1,25D3 have been observed in clinical trials. This may be attributed to a variety of factors including overexpression of the primary 1,25D3 degrading enzyme, CYP24A1, in tumors, which would lead to rapid local inactivation of 1,25D3. An alternative strategy for improving the antitumor activity of 1,25D3 involves the combination with a selective CYP24A1 inhibitor. The validity of this approach is supported by numerous preclinical investigations, which demonstrate that CYP24A1 inhibitors suppress 1,25D3 catabolism in tumor cells and increase the effects of 1,25D3 on gene expression and cell growth. Studies are now required to determine whether selective CYP24A1 inhibitors+1,25D3 can be used safely and effectively in patients. CYP24A1 inhibitors plus 1,25D3 can cause dose-limiting toxicity of vitamin D (hypercalcemia) in some patients. Dexamethasone significantly reduces 1,25D3-mediated hypercalcemia and enhances the antitumor activity of 1,25D3, increases VDR-ligand binding, and increases VDR protein expression. Efforts to dissect the mechanisms responsible for CYP24A1 overexpression and combinational effect of 1,25D3/dexamethasone in tumors are underway. Understanding the cross talk between vitamin D receptor (VDR) and glucocorticoid receptor (GR) signaling axes is of crucial importance to the design of new therapies that include 1,25D3 and dexamethasone. Insights gained from these studies are expected to yield novel strategies to improve the efficacy of 1,25D3 treatment.

  7. Performance Evaluation of the New Compound-Carrier-Modulated Signal for Future Navigation Signals

    Directory of Open Access Journals (Sweden)

    Ruidan Luo

    2016-01-01

    Full Text Available Navigation Signal based on Compound Carrier (NSCC, is proposed as the potential future global navigation satellite system (GNSS signal modulation scheme. NSCC, a kind of multi-carrier (MC signal, is generated by superposition and multi-parameter adjustment of sub-carriers. Therefore, a judious choice of parameter configation is needed. The main objective of this paper is to investigate the performance of the NSCC which is influenced by these parameters and to demonstrate its structure characteristics and superiority, employing a comprehensive evaluation system. The results show that the proposed NSCC signal processes full spectral efficiency and limited out of band (OOB emissions, satisfying the demands of crowed frequency resources. It also presents better performance in terms of spectral separation coefficients (SSCs, tracking accuracy, multipath mitigation capability and anti-jamming reduction compared with the legacy navigation signals. NSCC modulation represents a serious candidate for navigation satellite augmentation systems, especially for signals applied in challenging environments.

  8. Modulation of photoacoustic signal generation from metallic surfaces

    Science.gov (United States)

    Mitcham, Trevor; Homan, Kimberly; Frey, Wolfgang; Chen, Yun-Sheng; Emelianov, Stanislav; Hazle, John; Bouchard, Richard

    2013-05-01

    The ability to image metallic implants is important for medical applications ranging from diagnosis to therapy. Photoacoustic (PA) imaging has been recently pursued as a means to localize metallic implants in soft tissue. The work presented herein investigates different mechanisms to modulate the PA signal generated by macroscopic metallic surfaces. Wires of five different metals are tested to simulate medical implants/tools, while surface roughness is altered or physical vapor deposition (PVD) coatings are added to change the wires' overall optical absorption. PA imaging data of the wires are acquired at 970 nm. Results indicate that PA signal generation predominately occurs in a wire's metallic surface and not its aqueous surroundings. PA signal generation is similar for all metals tested, while addition of PVD coatings offers significant modulations (i.e., 4-dB enhancement and 26-dB reduction achieved) in PA signal generation. Results also suggest that PA signal increases with increasing surface roughness. Different coating and roughness schemes are then successfully utilized to generate spatial PA signal patterns. This work demonstrates the potential of surface modifications to enhance or reduce PA signal generation to permit improved PA imaging of implants/tools (i.e., providing location/orientation information) or to allow PA imaging of surrounding tissue.

  9. Frequency-dependent signal transmission and modulation by neuromodulators

    Directory of Open Access Journals (Sweden)

    Hiroshi T Ito

    2008-12-01

    Full Text Available The brain uses a strategy of labor division, which may allow it to accomplish more elaborate and complicated tasks, but in turn, imposes a requirement for central control to integrate information among different brain areas. Anatomically, the divergence of long-range neuromodulator projections appears well-suited to coordinate communication between brain areas. Oscillatory brain activity is a prominent feature of neural transmission. Thus, the ability of neuromodulators to modulate signal transmission in a frequency-dependent manner adds an additional level of regulation. Here, we review the significance of frequency-dependent signal modulation in brain function and how a neuronal network can possess such properties. We also describe how a neuromodulator, dopamine, changes frequency-dependent signal transmission, controlling information flow from the entorhinal cortex to the hippocampus.

  10. Coco is a dual activity modulator of TGFβ signaling

    Science.gov (United States)

    Deglincerti, Alessia; Haremaki, Tomomi; Warmflash, Aryeh; Sorre, Benoit; Brivanlou, Ali H.

    2015-01-01

    The TGFβ signaling pathway is a crucial regulator of developmental processes and disease. The activity of TGFβ ligands is modulated by various families of soluble inhibitors that interfere with the interactions between ligands and receptors. In an unbiased, genome-wide RNAi screen to identify genes involved in ligand-dependent signaling, we unexpectedly identified the BMP/Activin/Nodal inhibitor Coco as an enhancer of TGFβ1 signaling. Coco synergizes with TGFβ1 in both cell culture and Xenopus explants. Molecularly, Coco binds to TGFβ1 and enhances TGFβ1 binding to its receptor Alk5. Thus, Coco acts as both an inhibitor and an enhancer of signaling depending on the ligand it binds. This finding raises the need for a global reconsideration of the molecular mechanisms regulating TGFβ signaling. PMID:26116664

  11. Fractal Reference Signals in Pulse-Width Modulation

    Science.gov (United States)

    Lurie, Boris; Lurie, Helen

    2005-01-01

    A report proposes the use of waveforms having fractal shapes reminiscent of sawteeth (in contradistinction to conventional regular sawtooth waveforms) as reference signals for pulse-width modulation in control systems for thrusters of spacecraft flying in formation. Fractal reference signals may also be attractive in some terrestrial control systems - especially those in which pulse-width modulation is used for precise control of electric motors. The report asserts that the use of fractal reference signals would enable the synchronous control of several variables of a spacecraft formation, such that consumption of propellant would be minimized, intervals between thruster firings would be long (as preferred for performing scientific observations), and delays in controlling large-thrust maneuvers for retargeting would be minimized. The report further asserts that whereas different controllers would be needed for different modes of operation if conventional pulsewidth modulation were used, the use of fractal reference signals would enable the same controller to function nearly optimally in all regimes of operation, so that only this one controller would be needed.

  12. GABAB receptors modulate NMDA receptor calcium signals in dendritic spines.

    Science.gov (United States)

    Chalifoux, Jason R; Carter, Adam G

    2010-04-15

    Metabotropic GABA(B) receptors play a fundamental role in modulating the excitability of neurons and circuits throughout the brain. These receptors influence synaptic transmission by inhibiting presynaptic release or activating postsynaptic potassium channels. However, their ability to directly influence different types of postsynaptic glutamate receptors remains unresolved. Here we examine GABA(B) receptor modulation in layer 2/3 pyramidal neurons from the mouse prefrontal cortex. We use two-photon laser-scanning microscopy to study synaptic modulation at individual dendritic spines. Using two-photon optical quantal analysis, we first demonstrate robust presynaptic modulation of multivesicular release at single synapses. Using two-photon glutamate uncaging, we then reveal that GABA(B) receptors strongly inhibit NMDA receptor calcium signals. This postsynaptic modulation occurs via the PKA pathway and does not affect synaptic currents mediated by AMPA or NMDA receptors. This form of GABA(B) receptor modulation has widespread implications for the control of calcium-dependent neuronal function.

  13. Modulation of EEG Theta Band Signal Complexity by Music Therapy

    Science.gov (United States)

    Bhattacharya, Joydeep; Lee, Eun-Jeong

    The primary goal of this study was to investigate the impact of monochord (MC) sounds, a type of archaic sounds used in music therapy, on the neural complexity of EEG signals obtained from patients undergoing chemotherapy. The secondary goal was to compare the EEG signal complexity values for monochords with those for progressive muscle relaxation (PMR), an alternative therapy for relaxation. Forty cancer patients were randomly allocated to one of the two relaxation groups, MC and PMR, over a period of six months; continuous EEG signals were recorded during the first and last sessions. EEG signals were analyzed by applying signal mode complexity, a measure of complexity of neuronal oscillations. Across sessions, both groups showed a modulation of complexity of beta-2 band (20-29Hz) at midfrontal regions, but only MC group showed a modulation of complexity of theta band (3.5-7.5Hz) at posterior regions. Therefore, the neuronal complexity patterns showed different changes in EEG frequency band specific complexity resulting in two different types of interventions. Moreover, the different neural responses to listening to monochords and PMR were observed after regular relaxation interventions over a short time span.

  14. Symbol rate identification for auxiliary amplitude modulation optical signal

    Science.gov (United States)

    Wei, Junyu; Dong, Zhi; Huang, Zhiping; Zhang, Yimeng

    2016-09-01

    In this paper, we creatively propose and demonstrate a method for symbol rate identification (SRI) of auxiliary amplitude modulation (AAM) optical signal based on asynchronous delay-tap sampling (ADTS) and average magnitude difference function (AMDF). The method can accurately estimate symbol rate and has large transmission impairments tolerance. Furthermore, it can be realized in the digital signal processor (DSP) with low logical resources because of multiplication-free. In order to improve the accuracy of SRI, the peak to valley ratio (PTVR) of AMDF is introduced into our method for blind chromatic dispersion (CD) compensation. The results of the numerical simulations show that the overall maximum SRI error is smaller 0.079% for return-to-zero (RZ) on-off keying (OOK), RZ differential phase-shift keying (DPSK), RZ differential quadrature phase-shift keying (DQPSK) and RZ 16-ary quadrature amplitude modulation (QAM) with 50% duty cycles.

  15. Learning and Visualizing Modulation Discriminative Radio Signal Features

    Science.gov (United States)

    2016-09-01

    valued temporal domain radio signals. We propose a method for accomplishing online semi-supervised learning with a tied- weight convolutional...reduction of X. Additionally, if φ is parameterized by a weight matrix W and ψ = W T , this method is known as weight tying and has the desirable...waveforms’ input. This binary data is modulated as in-phase and quadrature (I/Q) samples using each of six methods : on-off keying (OOK), Gaussian

  16. Amplitude Modulated Sinusoidal Signal Decomposition for Audio Coding

    DEFF Research Database (Denmark)

    Christensen, M. G.; Jacobson, A.; Andersen, S. V.

    2006-01-01

    In this paper, we present a decomposition for sinusoidal coding of audio, based on an amplitude modulation of sinusoids via a linear combination of arbitrary basis vectors. The proposed method, which incorporates a perceptual distortion measure, is based on a relaxation of a nonlinear least......-squares minimization. Rate-distortion curves and listening tests show that, compared to a constant-amplitude sinusoidal coder, the proposed decomposition offers perceptually significant improvements in critical transient signals....

  17. Gpr125 modulates Dishevelled distribution and planar cell polarity signaling.

    Science.gov (United States)

    Li, Xin; Roszko, Isabelle; Sepich, Diane S; Ni, Mingwei; Hamm, Heidi E; Marlow, Florence L; Solnica-Krezel, Lilianna

    2013-07-01

    During vertebrate gastrulation, Wnt/planar cell polarity (PCP) signaling orchestrates polarized cell behaviors underlying convergence and extension (C&E) movements to narrow embryonic tissues mediolaterally and lengthen them anteroposteriorly. Here, we have identified Gpr125, an adhesion G protein-coupled receptor, as a novel modulator of the Wnt/PCP signaling system. Excess Gpr125 impaired C&E movements and the underlying cell and molecular polarities. Reduced Gpr125 function exacerbated the C&E and facial branchiomotor neuron (FBMN) migration defects of embryos with reduced Wnt/PCP signaling. At the molecular level, Gpr125 recruited Dishevelled to the cell membrane, a prerequisite for Wnt/PCP activation. Moreover, Gpr125 and Dvl mutually clustered one another to form discrete membrane subdomains, and the Gpr125 intracellular domain directly interacted with Dvl in pull-down assays. Intriguingly, Dvl and Gpr125 were able to recruit a subset of PCP components into membrane subdomains, suggesting that Gpr125 may modulate the composition of Wnt/PCP membrane complexes. Our study reveals a role for Gpr125 in PCP-mediated processes and provides mechanistic insight into Wnt/PCP signaling.

  18. DMPD: Cytokine signaling modules in inflammatory responses. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18400190 Cytokine signaling modules in inflammatory responses. O'Shea JJ, Murray PJ...tory responses. PubmedID 18400190 Title Cytokine signaling modules in inflammatory responses. Authors O'Shea JJ, Murray

  19. Performance of Deconvolution Methods in Estimating CBOC-Modulated Signals

    Directory of Open Access Journals (Sweden)

    Danai Skournetou

    2011-01-01

    Full Text Available Multipath propagation is one of the most difficult error sources to compensate in global navigation satellite systems due to its environment-specific nature. In order to gain a better understanding of its impact on the received signal, the establishment of a theoretical performance limit can be of great assistance. In this paper, we derive the Cramer Rao lower bounds (CRLBs, where in one case, the unknown parameter vector corresponds to any of the three multipath signal parameters of carrier phase, code delay, and amplitude, and in the second case, all possible combinations of joint parameter estimation are considered. Furthermore, we study how various channel parameters affect the computed CRLBs, and we use these bounds to compare the performance of three deconvolution methods: least squares, minimum mean square error, and projection onto convex space. In all our simulations, we employ CBOC modulation, which is the one selected for future Galileo E1 signals.

  20. Delta- Sigma Modulator with Signal Dependant Feedback Gain

    Directory of Open Access Journals (Sweden)

    K.Diwakar

    2015-02-01

    Full Text Available Higher order Delta-Sigma Modulator (DSM is basically an unstable system. The approximate conditions for stability cannot be used for the design of a DSM for industrial applications where risk is involved. The conventional second order, single stage, single bit, unity feedback gain, discrete DSM cannot be used for the normalized full range (-1 to +1 of input signal since the DSM becomes unstable when the modulus of the input signal is above 0.55. The stability is also not guaranteed for amplitude of input signal less than 0.55. In this proposal, the conventional second order DSM is modified with input signal dependant feedback path gain. The proposed DSM is suitable for industrial applications where one needs the digital representation of the analog input signal, during each sampling period. This first configuration of proposed DSM can operate for the full range of input signal without causing instability. In order to improve the SNR of first configuration, it is combined with conventional second order DSM and proposed the second configuration of DSM.

  1. Optical modulation techniques for analog signal processing and CMOS compatible electro-optic modulation

    Science.gov (United States)

    Gill, Douglas M.; Rasras, Mahmoud; Tu, Kun-Yii; Chen, Young-Kai; White, Alice E.; Patel, Sanjay S.; Carothers, Daniel; Pomerene, Andrew; Kamocsai, Robert; Beattie, James; Kopa, Anthony; Apsel, Alyssa; Beals, Mark; Mitchel, Jurgen; Liu, Jifeng; Kimerling, Lionel C.

    2008-02-01

    Integrating electronic and photonic functions onto a single silicon-based chip using techniques compatible with mass-production CMOS electronics will enable new design paradigms for existing system architectures and open new opportunities for electro-optic applications with the potential to dramatically change the management, cost, footprint, weight, and power consumption of today's communication systems. While broadband analog system applications represent a smaller volume market than that for digital data transmission, there are significant deployments of analog electro-optic systems for commercial and military applications. Broadband linear modulation is a critical building block in optical analog signal processing and also could have significant applications in digital communication systems. Recently, broadband electro-optic modulators on a silicon platform have been demonstrated based on the plasma dispersion effect. The use of the plasma dispersion effect within a CMOS compatible waveguide creates new challenges and opportunities for analog signal processing since the index and propagation loss change within the waveguide during modulation. We will review the current status of silicon-based electrooptic modulators and also linearization techniques for optical modulation.

  2. Seasonal modulation in the Borexino cosmic muon signal

    CERN Document Server

    D'Angelo, Davide

    2011-01-01

    Borexino is an organic liquid scintillator detector located in the underground Gran Sasso National Laboratory (Italy). It is devoted mainly to the real time spectroscopy of low energy solar neutrinos via the elastic scattering on electrons in the target mass. The data taking campaign started in 2007 and led to key measurements of 7}Be and 8B solar neutrinos as well as antineutrinos from the earth (geo-neutrinos) and from nuclear power reactors. Borexino is also a powerful tool for the study of cosmic muons that penetrate the Gran Sasso rock coverage and thereby induced signals such as neutrons and radioactive isotopes which are today of critical importance for upcoming dark matter and neutrino physics experiments. Having reached 4y of continuous data taking we analyze here the muon signal and its possible modulation. The muon flux is measured to be (3.41+-0.01)E-4/m2/s. A modulation of this signal with a yearly period is observed with an amplitude of (1.29+-0.07)% and a phase of (179+-6) d, corresponding to J...

  3. Lats2 modulates adipocyte proliferation and differentiation via hippo signaling.

    Directory of Open Access Journals (Sweden)

    Yang An

    Full Text Available First identified in Drosophila and highly conserved in mammals, the Hippo pathway controls organ size. Lats2 is one of the core kinases of the Hippo pathway and plays major roles in cell proliferation by interacting with the downstream transcriptional cofactors YAP and TAZ. Although the function of the Hippo pathway and Lats2 is relatively well understood in several tissues and organs, less is known about the function of Lats2 and Hippo signaling in adipose development. Here, we show that Lats2 is an important modulator of adipocyte proliferation and differentiation via Hippo signaling. Upon activation, Lats2 phosphorylates YAP and TAZ, leading to their retention in the cytoplasm, preventing them from activating the transcription factor TEAD in the nucleus. Because TAZ remains in the cytoplasm, PPARγ regains its transcriptional activity. Furthermore, cytoplasmic TAZ acts as an inhibitor of Wnt signaling by suppressing DVL2, thereby preventing β-catenin from entering the nucleus to stimulate TCF/LEF transcriptional activity. The above effects contribute to the phenotype of repressed proliferation and accelerated differentiation in adipocytes. Thus, Lats2 regulates the balance between proliferation and differentiation during adipose development. Interestingly, our study provides evidence that Lats2 not only negatively modulates cell proliferation but also positively regulates cell differentiation.

  4. Modulation of host-cell MAPkinase signaling during fungal infection

    Directory of Open Access Journals (Sweden)

    Nir Osherov

    2015-10-01

    Full Text Available Fungal infections contribute substantially to human suffering and mortality. The interaction between fungal pathogens and their host involves the invasion and penetration of the surface epithelium, activation of cells of the innate immune system and the generation of an effective response to block infection. Numerous host-cell signaling pathways are activated during fungal infection. This review will focus on the main fungal pathogens Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans and their ability to activate the host MAP-kinase signaling pathways leading to cytokine secretion, increased cell motility and killing of the pathogen. Both epithelial and innate immune cells specifically recognize fungal antigens and in particular cell surface polysaccharides such as β-glucans and react to them by activating multiple signaling pathways, including those containing MAP-kinase modules. Recent findings suggest that the host response to fungal infection utilizes the MAP-kinase pathway to differentiate between commensal and pathogenic fungi to selectively react only to the pathogenic forms. However, the paucity of relevant publications strongly emphasize that our understanding of host MAP-kinase signaling in response to fungal infection is still at a very early stage. It is clear, based on studies of host MAP-kinase signaling during viral and bacterial infections, that in fungi as well, a wealth of exciting findings await us.

  5. Modulation of Hippocampal Neural Plasticity by Glucose-Related Signaling

    Directory of Open Access Journals (Sweden)

    Marco Mainardi

    2015-01-01

    Full Text Available Hormones and peptides involved in glucose homeostasis are emerging as important modulators of neural plasticity. In this regard, increasing evidence shows that molecules such as insulin, insulin-like growth factor-I, glucagon-like peptide-1, and ghrelin impact on the function of the hippocampus, which is a key area for learning and memory. Indeed, all these factors affect fundamental hippocampal properties including synaptic plasticity (i.e., synapse potentiation and depression, structural plasticity (i.e., dynamics of dendritic spines, and adult neurogenesis, thus leading to modifications in cognitive performance. Here, we review the main mechanisms underlying the effects of glucose metabolism on hippocampal physiology. In particular, we discuss the role of these signals in the modulation of cognitive functions and their potential implications in dysmetabolism-related cognitive decline.

  6. Isolation of key retinoid signalling and metabolic modules in invertebrates

    Directory of Open Access Journals (Sweden)

    Ana André

    2014-05-01

    Full Text Available Retinoids are a class of molecules related to vitamin A (Retinol that are required for regulation of critical chordate ndocrine-mediated process, such as embryonic development, reproduction, and vision. To maintain such physiological process, chordates have a complex mechanism to regulate the spatial and temporal distribution of retinoids that includes metabolic and signalling modules. Initially, retinoid modules were seen as a chordate novelty. However, emerging biochemical and genomic evidences have challenged this view, clearly pointing to a more basal ancestry than previously thought. However, for the majority of non-chordate invertebrate lineages a clearly characterization of the main enzymatic/molecular players is still missing. Despite limited, the available evidence supports the presence of biologically active retinoid pathways in invertebrates. In order to enhance our insights on retinoid biology, evolution, and its putative disruption by environmental chemicals, the isolation and functional characterization of key retinoid metabolic players in marine invertebrates has been carried out.

  7. Modulation of hippocampal neural plasticity by glucose-related signaling.

    Science.gov (United States)

    Mainardi, Marco; Fusco, Salvatore; Grassi, Claudio

    2015-01-01

    Hormones and peptides involved in glucose homeostasis are emerging as important modulators of neural plasticity. In this regard, increasing evidence shows that molecules such as insulin, insulin-like growth factor-I, glucagon-like peptide-1, and ghrelin impact on the function of the hippocampus, which is a key area for learning and memory. Indeed, all these factors affect fundamental hippocampal properties including synaptic plasticity (i.e., synapse potentiation and depression), structural plasticity (i.e., dynamics of dendritic spines), and adult neurogenesis, thus leading to modifications in cognitive performance. Here, we review the main mechanisms underlying the effects of glucose metabolism on hippocampal physiology. In particular, we discuss the role of these signals in the modulation of cognitive functions and their potential implications in dysmetabolism-related cognitive decline.

  8. An Acquisition Algorithm with NCCFR for BOC Modulated Signals

    Directory of Open Access Journals (Sweden)

    Yongxin Feng

    2017-01-01

    Full Text Available With the development of satellite navigation technology, BOC (Binary Offset Carrier signals are proposed and applied in navigation system. However, in the advantages of enhancing the utilized rating of the band resource, some new problems are also emerging in the acquisition processing. On the basis of analyzing the limitations of the existing methods in suppressing side peaks, a NCCFR (New Cross-Correlation Function Reconstruction algorithm is proposed, in which different modulation coefficients are used to construct correlation function with a shifter phase. The simulation results show that the new algorithm can suppress first side peaks and restrain other side peaks.

  9. Modulation of the matrix redox signaling by mitochondrial Ca(2.).

    Science.gov (United States)

    Santo-Domingo, Jaime; Wiederkehr, Andreas; De Marchi, Umberto

    2015-11-26

    Mitochondria sense, shape and integrate signals, and thus function as central players in cellular signal transduction. Ca(2+) waves and redox reactions are two such intracellular signals modulated by mitochondria. Mitochondrial Ca(2+) transport is of utmost physio-pathological relevance with a strong impact on metabolism and cell fate. Despite its importance, the molecular nature of the proteins involved in mitochondrial Ca(2+) transport has been revealed only recently. Mitochondrial Ca(2+) promotes energy metabolism through the activation of matrix dehydrogenases and down-stream stimulation of the respiratory chain. These changes also alter the mitochondrial NAD(P)H/NAD(P)(+) ratio, but at the same time will increase reactive oxygen species (ROS) production. Reducing equivalents and ROS are having opposite effects on the mitochondrial redox state, which are hard to dissect. With the recent development of genetically encoded mitochondrial-targeted redox-sensitive sensors, real-time monitoring of matrix thiol redox dynamics has become possible. The discoveries of the molecular nature of mitochondrial transporters of Ca(2+) combined with the utilization of the novel redox sensors is shedding light on the complex relation between mitochondrial Ca(2+) and redox signals and their impact on cell function. In this review, we describe mitochondrial Ca(2+) handling, focusing on a number of newly identified proteins involved in mitochondrial Ca(2+) uptake and release. We further discuss our recent findings, revealing how mitochondrial Ca(2+) influences the matrix redox state. As a result, mitochondrial Ca(2+) is able to modulate the many mitochondrial redox-regulated processes linked to normal physiology and disease.

  10. Modulation of the matrix redox signaling by mitochondrial Ca2+

    Institute of Scientific and Technical Information of China (English)

    Jaime; Santo-Domingo; Andreas; Wiederkehr; Umberto; De; Marchi

    2015-01-01

    Mitochondria sense,shape and integrate signals,and thus function as central players in cellular signal transduction. Ca2+ waves and redox reactions are two such intracellular signals modulated by mitochondria. Mitochondrial Ca2+ transport is of utmost physio-pathological relevance with a strong impact on metabolism and cell fate. Despite its importance,the molecular nature of the proteins involvedin mitochondrial Ca2+ transport has been revealed only recently. Mitochondrial Ca2+ promotes energy metabolism through the activation of matrix dehydrogenases and downstream stimulation of the respiratory chain. These changes also alter the mitochondrial NAD(P)H/NAD(P)+ ratio,but at the same time will increase reactive oxygen species(ROS) production. Reducing equivalents and ROS are having opposite effects on the mitochondrial redox state,which are hard to dissect. With the recent development of genetically encoded mitochondrial-targeted redoxsensitive sensors,real-time monitoring of matrix thiol redox dynamics has become possible. The discoveries of the molecular nature of mitochondrial transporters of Ca2+ combined with the utilization of the novel redox sensors is shedding light on the complex relation between mitochondrial Ca2+ and redox signals and their impact on cell function. In this review,we describe mitochondrial Ca2+ handling,focusing on a number of newly identified proteins involved in mitochondrial Ca2+ uptake and release. We further discuss our recent findings,revealing how mitochondrial Ca2+ influences the matrix redox state. As a result,mitochondrial Ca2+ is able to modulate the many mitochondrial redox-regulated processes linked to normal physiology and disease.

  11. Semaphorin 6A regulates angiogenesis by modulating VEGF signaling

    Science.gov (United States)

    Segarra, Marta; Maric, Dragan; Salvucci, Ombretta; Hou, Xu; Kumar, Anil; Li, Xuri; Tosato, Giovanna

    2012-01-01

    Formation of new vessels during development and in the mature mammal generally proceeds through angiogenesis. Although a variety of molecules and signaling pathways are known to underlie endothelial cell sprouting and remodeling during angiogenesis, many aspects of this complex process remain unexplained. Here we show that the transmembrane semaphorin6A (Sema6A) is expressed in endothelial cells, and regulates endothelial cell survival and growth by modulating the expression and signaling of VEGFR2, which is known to maintain endothelial cell viability by autocrine VEGFR signaling. The silencing of Sema6A in primary endothelial cells promotes cell death that is not rescued by exogenous VEGF-A or FGF2, attributable to the loss of prosurvival signaling from endogenous VEGF. Analyses of mouse tissues demonstrate that Sema6A is expressed in angiogenic and remodeling vessels. Mice with null mutations of Sema6A exhibit significant defects in hyaloid vessels complexity associated with increased endothelial cell death, and in retinal vessels development that is abnormally reduced. Adult Sema6A-null mice exhibit reduced tumor, matrigel, and choroidal angiogenesis compared with controls. Sema6A plays important roles in development of the nervous system. Here we show that it also regulates vascular development and adult angiogenesis. PMID:23007403

  12. Influenza NS1 directly modulates Hedgehog signaling during infection.

    Directory of Open Access Journals (Sweden)

    Margery G Smelkinson

    2017-08-01

    Full Text Available The multifunctional NS1 protein of influenza A viruses suppresses host cellular defense mechanisms and subverts other cellular functions. We report here on a new role for NS1 in modifying cell-cell signaling via the Hedgehog (Hh pathway. Genetic epistasis experiments and FRET-FLIM assays in Drosophila suggest that NS1 interacts directly with the transcriptional mediator, Ci/Gli1. We further confirmed that Hh target genes are activated cell-autonomously in transfected human lung epithelial cells expressing NS1, and in infected mouse lungs. We identified a point mutation in NS1, A122V, that modulates this activity in a context-dependent fashion. When the A122V mutation was incorporated into a mouse-adapted influenza A virus, it cell-autonomously enhanced expression of some Hh targets in the mouse lung, including IL6, and hastened lethality. These results indicate that, in addition to its multiple intracellular functions, NS1 also modifies a highly conserved signaling pathway, at least in part via cell autonomous activities. We discuss how this new Hh modulating function of NS1 may influence host lethality, possibly through controlling cytokine production, and how these new insights provide potential strategies for combating infection.

  13. Multi-carrier Modulation (MCM) Signaling using OFDM Technique

    Science.gov (United States)

    Umadevi, H.; Gowda, Chandrakanth H.; Gurumurthy, K. S.

    2011-12-01

    OFDM is novel multicarrier modulation (MCM) technique. It has strong advantage of being a generic transmission scheme whose actual characteristics can be widely customized to fulfill several requirements and constraints of an advanced communication system. It adopts wavelet packet function as carriers which have the characteristic of good orthogonality and time-frequency localization. It can be seen from both theoretical analysis and software simulation that multi-carrier modulation and demodulation technique based on wavelet packet transform has unique advantage and great potential in improving the performance of communication system. This paper demonstrates the operation of a Wavelet Packet based multi-carrier modulation (WP-MCM) scheme. The wavelet packets are derived from multistage tree-structured paraunitary filter banks by choosing the right tree structure which would minimize the bit error between the desired and received signal for a particular channel condition. The performance of the system is simulated and analyzed for the AWGN channel. Through simulation results, we demonstrate the efficacy and the flexibility of the proposed wavelet packet based mechanism. The Bit Error rate (BER) performance is shown to be comparable, and even at times better, to conventional Fourier based OFDM. Comparison of different family of wavelets has been carried out and Meyer wavelet seems to be the most suitable wavelet through simulation results.

  14. Soft demodulation to the optical pulse position modulated signals

    Science.gov (United States)

    Zhou, Tian-hua; Chen, Wei-biao

    2009-07-01

    The optical Pulse Position Modulation (PPM) is applied widely in Free Space Optical communication (FSO) with the low average power and the high peak power. The transmitted PPM information depends on the location of the coming optical pulse signals in fixed period. Both receiver and transmitter should been kept in time slot synchronization and frame synchronization in demodulation. Because the channel is very complex, the received optical pulse width will be stretched randomly. We design and realize one digital PPM modulation receiver with high sensitivity using the technology of PMT, A/D converter, and DSP. It is suitable to the total digital optical receiver with random time slots and random pulse width. The paper will mainly discuss the realization of the soft demodulation behind A/D converter. The key of PPM digital soft modulation is the establishment of the synchronization that involves the segment synchronization, the fame synchronization and the bit synchronization. The synchronization can be obtained by seeking for the frame head in data frames. Based on the estimation of received waveform characteristics, we adopt a matched filter without the best factors firstly. Thereafter, their errors will be self-adapted while finding the synchronization head. Considering the real-time need, we choose the reduced mode of maximum likelihood function judgment finally. In the experiments, results with high sensitivity and low bit error rate have been achieved.

  15. Targeting multiple signaling pathways as a strategy for managing prostate cancer: multifocal signal modulation therapy.

    Science.gov (United States)

    McCarty, Mark F

    2004-12-01

    The aberrant behavior of cancer reflects upregulation of certain oncogenic signaling pathways that promote proliferation, inhibit apoptosis, and enable the cancer to spread and evoke angiogenesis. Theoretically, it should be feasible to decrease the activity of these pathways-or increase the activity of pathways that oppose them-with noncytotoxic agents. Since multiple pathways are dysfunctional in most cancers, and cancers accumulate new oncogenic mutations as they progress, the greatest and most durable therapeutic benefit will likely be achieved with combination regimens that address several targets. Thus, a multifocal signal modulation therapy (MSMT) of cancer is proposed. This concept has already been documented by researchers who have shown that certain combinations of signal modulators-of limited utility when administered individually-can achieve dramatic suppression of tumor growth in rodent xenograft models. The present essay attempts to guide development of MSMTs for prostate cancer. Androgen ablation is a signal-modulating measure already in standard use in the management of delocalized prostate cancer. The additional molecular targets considered here include the type 1 insulin-like growth factor receptor, the epidermal growth factor receptor, mammalian target of rapamycin, NF-kappaB, hypoxia-inducible factor-1alpha, hsp90, cyclooxygenase-2, protein kinase A type I, vascular endothelial growth factor, 5-lipoxygenase, 12-lipoxygenase, angiotensin II receptor type 1, bradykinin receptor type 1, c-Src, interleukin-6, ras, MDM2, bcl-2/bclxL, vitamin D receptor, estrogen receptor-beta, and PPAR-. Various nutrients and phytochemicals suspected to have potential utility in prostate cancer prevention and therapy, but whose key molecular targets are still unknown, might reasonably be incorporated into MSMTs for prostate cancer; these include lycopene, selenium, green tea polyphenols, genistein, and silibinin. MSMTs can be developed systematically by testing

  16. Study of cross - relaxation and molecular dynamics in the solid 3-(trifluoromethyl) benzoic acid by solid state NMR off - resonance.

    Science.gov (United States)

    Woźniak-Braszak, Aneta

    2017-02-01

    Molecular dynamics of the solid 3-(trifluoromethyl) benzoic acid containing proton (1)H and fluorine (19)F nuclei was explored by the solid-state NMR off - resonance technique. Contrary to the previous experiments the proton nuclei system I relaxed in the off - resonance effective field B→e while fluorine nuclei system S was saturated for short time in comparison to the relaxation time T1I. New cross - relaxation solid - state NMR off - resonance experiments were conducted on a homebuilt pulse spectrometer operating at the on-resonance frequency of 30.2MHz, at the off - resonance frequency varied between 30.2 and 30.6MHz for protons and at the frequency of 28.411MHz for fluorines, respectively. Based on the experimental data the dispersions of the proton off - resonance spin - lattice relaxation rate ρρ(I), the fluorine off - resonance spin - lattice relaxation rate ρρ(S) and the cross - relaxation rate σρ in the rotating frame were determined. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. 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

  18. Arrays of surface-normal electroabsorption modulators for the generation and signal processing of microwave photonics signals

    NARCIS (Netherlands)

    Noharet, Bertrand; Wang, Qin; Platt, Duncan; Junique, Stéphane; Marpaung, D.A.I.; Roeloffzen, C.G.H.

    2011-01-01

    The development of an array of 16 surface-normal electroabsorption modulators operating at 1550nm is presented. The modulator array is dedicated to the generation and processing of microwave photonics signals, targeting a modulation bandwidth in excess of 5GHz. The hybrid integration of the

  19. Cellular metabolites modulate in vivo signaling of Arabidopsis cryptochrome-1

    Science.gov (United States)

    El-Esawi, Mohamed; Glascoe, Austin; Engle, Dorothy; Ritz, Thorsten; Link, Justin; Ahmad, Margaret

    2015-01-01

    Cryptochromes are blue-light absorbing flavoproteins with multiple signaling roles. In plants, cryptochrome (cry1, cry2) biological activity has been linked to flavin photoreduction via an electron transport chain to the protein surface comprising 3 evolutionarily conserved tryptophan residues known as the ‘Trp triad.’ Mutation of any of the Trp triad residues abolishes photoreduction in isolated cryptochrome protein in vitro and therefore had been suggested as essential for electron transfer to the flavin. However, photoreduction of the flavin in Arabidopsis cry2 proteins occurs in vivo even with mutations in the Trp triad, indicating the existence of alternative electron transfer pathways to the flavin. These pathways are potentiated by metabolites in the intracellular environment including ATP, ADP, AMP, and NADH. In the present work we extend these observations to Arabidopsis cryptochrome 1 and demonstrate that Trp triad substitution mutants at W400F and W324F positions which are not photoreduced in vitro can be photoreduced in whole cell extracts, albeit with reduced efficiency. We further show that the flavin signaling state (FADH°) is stabilized in an in vivo context. These data illustrate that in vivo modulation by metabolites in the cellular environment may play an important role in cryptochrome signaling, and are discussed with respect to possible effects on the conformation of the C-terminal domain to generate the biologically active conformational state. PMID:26313597

  20. DMPD: Modulation of Toll-interleukin 1 receptor mediated signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15662540 Modulation of Toll-interleukin 1 receptor mediated signaling. Li X, Qin J....iated signaling. PubmedID 15662540 Title Modulation of Toll-interleukin 1 receptor media... J Mol Med. 2005 Apr;83(4):258-66. Epub 2005 Jan 21. (.png) (.svg) (.html) (.csml) Show Modulation of Toll-interleukin 1 receptor med

  1. Optimization of Generation and Detection of WDM Signals with Advanced Modulation Formats

    Institute of Scientific and Technical Information of China (English)

    Sarah; Dods

    2003-01-01

    This paper presents optimal generation and detection of wavelength division multiplexed (WDM) signals with advanced modulation formats. We investigate the relative phase alignment between phase modulation and data bits for chirped return-to-zero (CRZ) signals, and the frequency offset between the RZ carrier and various optical filters for vestigial side band (VSB)-RZ signals.

  2. The potential characteristics analysis of probing signal with the quadratic frequency modulation

    Directory of Open Access Journals (Sweden)

    O. D. Mrachkovsky

    2012-12-01

    Full Text Available Introduction: Complex signals with the button ambiguity function can provide the distance and speed of target independent estimation. The signal with the symmetrical linear frequency modulation has this property in the class of signal with frequency modulation. Problem statement: To show that in the class of signals frequency-shift is signal with button ambiguity function. Such signal is a signal with the quadratic frequency intra-modulation. The potential characteristics research of signal with the quadratic frequency intra-modulation: The signal with quadratic frequency modulation and its properties are considered, analytic form of signal and its spectrum are shown, figures of amplitude spectra of signal are drawn, and figures of ambiguity diagram, cross-correlation functions and response ambiguity function in strong and weak fields are shown. The comparison of the signal with the quadratic frequency intra-modulation and the signal with the symmetrical linear frequency modulation are shown. The result of research is that the ambiguity function form of a signal with the quadratic frequency intra-modulation comes nearer to button in the strong correlation field and it has X – for min the weak correlation field. The autocorrelation function of the signal with the quadratic frequency intra-modulation has some constant level which decreases with signal base increasing. It is revealed that autocorrelation function of the signal has no side lobes. It improves resolution capability of a weak signal against the strong signal. The pedestal level of the autocorrelation function of this signal is a little lower than pedestal level of the autocorrelation function of the signal with the symmetrical linear frequency modulation. Properties of section of cross-correlation function to two peaks and effect of these properties are considered. Signals with the quadratic frequency intra-modulation are expedient for using in the sonar of submarines, because in

  3. Pump-to-Signal Intensity Modulation Transfer in Saturated- Gain Fiber Optical Parametric Amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke; Rottwitt, Karsten

    2011-01-01

    The pump-to-signal intensity modulation transfer in saturated degenerate FOPAs is numerically investigated over the whole gain bandwidth. The intensity modulation transfer decreases and the OSNR improves when the amplifier operates in the saturation regime....

  4. The hedgehog signal induced modulation of bone morphogenetic protein signaling: an essential signaling relay for urinary tract morphogenesis.

    Directory of Open Access Journals (Sweden)

    Ryuma Haraguchi

    Full Text Available BACKGROUND: Congenital diseases of the urinary tract are frequently observed in infants. Such diseases present a number of developmental anomalies such as hydroureter and hydronephrosis. Although some genetically-modified mouse models of growth factor signaling genes reproduce urinary phenotypes, the pathogenic mechanisms remain obscure. Previous studies suggest that a portion of the cells in the external genitalia and bladder are derived from peri-cloacal mesenchymal cells that receive Hedgehog (Hh signaling in the early developmental stages. We hypothesized that defects in such progenitor cells, which give rise to urinary tract tissues, may be a cause of such diseases. METHODOLOGY/PRINCIPAL FINDINGS: To elucidate the pathogenic mechanisms of upper urinary tract malformations, we analyzed a series of Sonic hedgehog (Shh deficient mice. Shh(-/- displayed hydroureter and hydronephrosis phenotypes and reduced expression of several developmental markers. In addition, we suggested that Shh modulation at an early embryonic stage is responsible for such phenotypes by analyzing the Shh conditional mutants. Tissue contribution assays of Hh-responsive cells revealed that peri-cloacal mesenchymal cells, which received Hh signal secreted from cloacal epithelium, could contribute to the ureteral mesenchyme. Gain- and loss-of-functional mutants for Hh signaling revealed a correlation between Hh signaling and Bone morphogenetic protein (Bmp signaling. Finally, a conditional ablation of Bmp receptor type IA (BmprIA gene was examined in Hh-responsive cell lineages. This system thus made it possible to analyze the primary functions of the growth factor signaling relay. The defective Hh-to-Bmp signaling relay resulted in severe urinary tract phenotypes with a decrease in the number of Hh-responsive cells. CONCLUSIONS/SIGNIFICANCE: This study identified the essential embryonic stages for the pathogenesis of urinary tract phenotypes. These results suggested that Hh

  5. Growth Culture Conditions and Nutrient Signaling Modulating Yeast Chronological Longevity

    Directory of Open Access Journals (Sweden)

    Júlia Santos

    2012-01-01

    Full Text Available The manipulation of nutrient-signaling pathways in yeast has uncovered the impact of environmental growth conditions in longevity. Studies using calorie restriction show that reducing glucose concentration of the culture media is sufficient to increase replicative and chronological lifespan (CLS. Other components of the culture media and factors such as the products of fermentation have also been implicated in the regulation of CLS. Acidification of the culture media mainly due to acetic acid and other organic acids production negatively impacts CLS. Ethanol is another fermentative metabolite capable of inducing CLS reduction in aged cells by yet unknown mechanisms. Recently, ammonium was reported to induce cell death associated with shortening of CLS. This effect is correlated to the concentration of NH4+ added to the culture medium and is particularly evident in cells starved for auxotrophy-complementing amino acids. Studies on the nutrient-signaling pathways regulating yeast aging had a significant impact on aging-related research, providing key insights into mechanisms that modulate aging and establishing the yeast as a powerful system to extend knowledge on longevity regulation in multicellular organisms.

  6. Approximation Formula for Easy Calculation of Signal-to-Noise Ratio of Sigma-Delta Modulators

    OpenAIRE

    2011-01-01

    The signal-to-noise ratio (SNR) is one of the most significant measures of performance of the sigma-delta modulators. An approximate formula for calculation of signal-to-noise ratio of an arbitrary sigma-delta modulator (SDM) has been proposed. Our approach for signal-to-noise ratio computation does not require modulator modeling and simulation. The proposed formula is compared with SNR calculations based on output bitstream obtained by simulations, and the reasons for small discrepancies are...

  7. Stochastic resonance at a subharmonic of a periodic modulation signal in solid-state lasers

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, N V; Lariontsev, E G; Chekina, S N [D.V. Skobel' tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2013-10-31

    The stochastic excitation of a subharmonic of a periodic modulation signal in the intensity spectrum of a solid-state laser is experimentally studied upon modulation of the pump rate by the noise and periodic signal. The stochastic resonance (SR) is observed in the presence of bistability in the laser. The conditions for SR at a subharmonic of the periodic modulation signal are determined. (control of laser radiation parameters)

  8. Analysis of small-signal intensity modulation of semiconductor lasers taking account of gain suppression

    Indian Academy of Sciences (India)

    Moustafa Ahmed; Ali El-Lafi

    2008-07-01

    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 derived. Influences of the bias current, modulation index and modulation frequency as well as gain suppression on modulation characteristics are examined. Computer simulation of the model is applied to 1.55-m InGaAsP lasers. The results show that when the SL is biased far-above threshold, the increase of gain suppression increases both the modulation response and its peak frequency. The modulation bandwidth also increases but the laser damping rate decreases. Quantitative description of the relationships of both modulation bandwidth vs. relaxation frequency and maximum modulation bandwidth vs. nonlinear gain coefficient are presented.

  9. Ultra-wideband signal generator based on cross gain modulation effect in a distributed feedback laser

    Science.gov (United States)

    Chen, Dalei; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Li, Yuandong; Su, Yang; Zheng, Jiling; Huang, Long; Zhu, Huatao; Huang, Jie

    2016-10-01

    In this paper, a novel scheme to generate ultra-wideband (UWB) signals based on cross-gain modulation (XGM) effect in a DFB laser is proposed and experimentally demonstrated, and the modulation and transmission of the UWB signals are also experimentally investigated. In the proposed system, a gain-switched laser (GSL) is used as master laser (ML) and the optical pulses from the ML are optically injected into a DFB laser, which is used as slave laser (SL). By proper system configuration, UWB monocycle, doublet or triplet UWB signals can be generated after the balanced photodiode (BPD) detection. Besides, other modulation formats can also be realized, such as on-off keying (OOK) and pulse amplitude modulation (PAM) by properly modulating the ML optical pulses. Finally, fiber transmission of the modulated UWB signals is experimentally investigated, and it is shown that the UWB signals can be well maintained after 40 km optical fiber transmission.

  10. Stochastic resonance in a single-mode laser driven by frequency modulated signal and coloured noises

    Institute of Scientific and Technical Information of China (English)

    Jin Guo-Xiang; Zhang Liang-Ying; Cao Li

    2009-01-01

    By adding frequency modulated signals to the intensity equation of gain-noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity. The results show that the SNR appears typical stochastic resonance with the variation of intensity of the pump noise and quantum noise. As the amplitude of a modulated signal has effects on the SNR, it shows suppression, monotone increasing, stochastic resonance, and multiple stochastic resonance with the variation of the frequency of a carrier signal and modulated signal.

  11. Research on Feature Extraction of Composite Pseudocode Phase Modulation-Carrier Frequency Modulation Signal Based on PWD Transform

    Institute of Scientific and Technical Information of China (English)

    LI Ming-zi; ZHAO Hui-chang

    2008-01-01

    The identification features of composite pseudocode phase modulation and carry frequency modulation signal in-clude pseudocode and modulation frequency. In this paper, PWD is used to extract these features. First, the feature of pseudocode is extracted using the amplitude output of PWD and the correlation filter technology. Then the feature of fre-quency modulation is extracted by way of PWD analysis on the signal processed by anti-phase operation according to the extracted feature of pseudo code, i.e. position information of changed abruptly point of phase. The simulation result shows that both the features of frequency modulation and phase change position caused by the pseudocode phase modula-tion can be extracted effectively for SNR = 3 dB.

  12. Modulation of neurotrophic signaling pathways by polyphenols

    Directory of Open Access Journals (Sweden)

    Moosavi F

    2015-12-01

    response element-binding protein (CREB phosphorylation. Finally, the antioxidant activity of polyphenols reflected in the activation of Nrf2 pathway and the consequent upregulation of detoxification enzymes such as heme oxygenase-1 as well as the contribution of these effects to the neurotrophic activity have also been discussed. In conclusion, a better understanding of the neurotrophic effects of polyphenols and the concomitant modulations of signaling pathways is useful for designing more effective agents for management of neurodegenerative diseases. Keywords: flavonoids, hydroxycinnamic acids, neuroprotective, neurodegeneration, Trk

  13. Code division multiple access signaling for modulated reflector technology

    Science.gov (United States)

    Briles, Scott D [Los Alamos, NM

    2012-05-01

    A method and apparatus for utilizing code division multiple access in modulated reflectance transmissions comprises the steps of generating a phase-modulated reflectance data bit stream; modifying the modulated reflectance data bit stream; providing the modified modulated reflectance data bit stream to a switch that connects an antenna to an infinite impedance in the event a "+1" is to be sent, or connects the antenna to ground in the event a "0" or a "-1" is to be sent.

  14. Simulation of mm-wave signal generation using phase modulation in ROF system

    Institute of Scientific and Technical Information of China (English)

    ZHANG da-peng; YU Chong-xiu; XIN Xiang-jun; MA Jian-xin; ZHANG Jin-long

    2009-01-01

    The generation of optical millimeter waves via the improved phase modulator in a RoF system and the transmission char-acter of the signal are thenretically investigated. A new phase modulating scheme is proposed, in which the sidebands are separated by wave length demultiplexer and one of them doesn't feed digital signals, thereby the phase wake-off is restrained.

  15. System and method of modulating electrical signals using photoconductive wide bandgap semiconductors as variable resistors

    Science.gov (United States)

    Harris, John Richardson; Caporaso, George J; Sampayan, Stephen E

    2013-10-22

    A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.

  16. Contextual modulation of primary visual cortex by auditory signals.

    Science.gov (United States)

    Petro, L S; Paton, A T; Muckli, L

    2017-02-19

    Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195-201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256-1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame.This article is part of the themed issue 'Auditory and visual scene analysis'.

  17. Contextual modulation of primary visual cortex by auditory signals

    Science.gov (United States)

    Paton, A. T.

    2017-01-01

    Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195–201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256–1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame. This article is part of the themed issue ‘Auditory and visual scene analysis’. PMID:28044015

  18. Autonomous non-linear classification of LPI radar signal modulations

    OpenAIRE

    Gulum, Taylan O.

    2007-01-01

    In this thesis, an autonomous feature extraction algorithm for classification of Low Probability of Intercept (LPI) radar modulations is investigated. A software engineering architecture that allows a full investigation of various preprocessing algorithms and classification techniques is applied to a database of important LPI radar waveform modulations including Frequency Modulation Continuous Waveform (FMCW), Phase Shift Keying (PSK), Frequency Shift Keying (FSK) and combined PSK and FSK. Th...

  19. All-optical wavelength conversion and signal regeneration using an electroabsorption modulator

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    2000-01-01

    All-optical wavelength conversion and signal regeneration based on cross-absorption modulation in an InGaAsP quantum well electroabsorption modulator (EAM) is studied at different bit rates. We present theoretical results showing wavelength conversion efficiency in agreement with existing...... experimental results, and the signal regeneration capability of the device is investigated. In particular, we demonstrate the dependence of the extinction ratio of both the converted signal and the control signal on the device length and on the power level of the control signal. We also show how the sweep...

  20. 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.

  1. Analysis of interference of QPSK and QDPSK modulation signals by mathematical

    Science.gov (United States)

    Li, Dairuo; Xu, Kai

    2017-03-01

    In today's society, with the rapid development and extensive application of the information technology of the network central station and the integrated information system technology, information plays an important role in the military communication, mastering the information right to the competition Important role, how to protect one's own security, smooth access to and transmission of information, and to maximize the elimination of interference has become an important issue at home and abroad. QPSK modulation and its improved QPSK modulation as the mainstream signal modulation, the most widely used. In this paper, the principle of QPSK and QDPSK modulation and demodulation are introduced in this paper. Then, how to interfere with QPSK modulation signal is analyzed, and the interference of QPSK modulation signal is simulated by Matlab scripting program, which can be used in the next step. And to study the next step of anti-jamming measures provided the basis and preparatory work.

  2. Cytosolic phospholipase A2 modulates TLR2 signaling in synoviocytes.

    Directory of Open Access Journals (Sweden)

    Randi M Sommerfelt

    Full Text Available Rheumatoid arthritis (RA is an autoimmune disease characterized by chronic synovitis leading to destruction of cartilage and bone. PLA2 enzymes are key players in inflammation regulating the release of unsaturated fatty acids such as arachidonic acid (AA, a precursor of pro-inflammatory eicosanoids. Several lines of evidence point to toll-like receptors (TLRs as drivers of synovitis and joint destruction in RA. However, few studies have addressed the implication of PLA2 activity downstream TLR activation in the synovium. Here, we aimed to characterize PLA2 enzyme involvement in TLR2-induced signaling in synovial fibroblast-like cells. TLRs1-7 and a range of sPLA2, iPLA2 and cPLA2 enzymes were found to be transcriptionally expressed in cultured synoviocytes. Activation of TLR2/1 and TLR2/6 led to phosphorylation of cPLA2α at Ser505, and induced AA release and PGE2 production; effects that were attenuated by cPLA2α inhibitors. In contrast, sPLA2 inhibitors did not affect AA or PGE2 release. cPLA2α inhibitors furthermore attenuated TLR-induced expression of IL-6, IL-8 and COX2. COX1/2 inhibitors attenuated TLR2/6-induced IL-6 transcription and protein production comparable to cPLA2α inhibition. Moreover, exogenously PGE2 added alone induced IL-6 production and completely rescued IL-6 transcription when added simultaneously with FSL-1 in the presence of a cPLA2α inhibitor. Our results demonstrate for the first time that cPLA2α is involved in TLR2/1- and TLR2/6-induced AA release, PGE2 production and pro-inflammatory cytokine expression in synoviocytes, possibly through COX/PGE2-dependent pathways. These findings expand our understanding of cPLA2α as a modulator of inflammatory molecular mechanisms in chronic diseases such as RA.

  3. AUTOMATIC RECOGNITION OF BOTH INTER AND INTRA CLASSES OF DIGITAL MODULATED SIGNALS USING ARTIFICIAL NEURAL NETWORK

    Directory of Open Access Journals (Sweden)

    JIDE JULIUS POPOOLA

    2014-04-01

    Full Text Available In radio communication systems, signal modulation format recognition is a significant characteristic used in radio signal monitoring and identification. Over the past few decades, modulation formats have become increasingly complex, which has led to the problem of how to accurately and promptly recognize a modulation format. In addressing these challenges, the development of automatic modulation recognition systems that can classify a radio signal’s modulation format has received worldwide attention. Decision-theoretic methods and pattern recognition solutions are the two typical automatic modulation recognition approaches. While decision-theoretic approaches use probabilistic or likelihood functions, pattern recognition uses feature-based methods. This study applies the pattern recognition approach based on statistical parameters, using an artificial neural network to classify five different digital modulation formats. The paper deals with automatic recognition of both inter-and intra-classes of digitally modulated signals in contrast to most of the existing algorithms in literature that deal with either inter-class or intra-class modulation format recognition. The results of this study show that accurate and prompt modulation recognition is possible beyond the lower bound of 5 dB commonly acclaimed in literature. The other significant contribution of this paper is the usage of the Python programming language which reduces computational complexity that characterizes other automatic modulation recognition classifiers developed using the conventional MATLAB neural network toolbox.

  4. Transmission Property of Directly Modulated Signals Enhanced by a Micro-ring Resonator

    DEFF Research Database (Denmark)

    An, Yi; Lorences Riesgo, Abel; Seoane, Jorge;

    2012-01-01

    A silicon micro-ring resonator is used to enhance the modulation speed of a 10-Gbit/s directly modulated laser to 40 Gbit/s. The generated signal is transmitted error free over 4.5 km SSMF. Dispersion tolerance is also studied.......A silicon micro-ring resonator is used to enhance the modulation speed of a 10-Gbit/s directly modulated laser to 40 Gbit/s. The generated signal is transmitted error free over 4.5 km SSMF. Dispersion tolerance is also studied....

  5. Design of a piezoelectric transducer cylindrical phase modulator for simulating acoustic emission signals

    Institute of Scientific and Technical Information of China (English)

    HE Cunfu; HANG Lijun; WU Bin

    2007-01-01

    To conveniently carry out the pipeline leak experiment in a laboratory,leak acoustic signals are simulated by using the converse piezoelectric effect of a piezoelectric transducer (PZT) cylindrical phase modulator.On the basis of the piezoelectric equations and electromechanical equivalence principle,the transfer function of a PZT cylindrical phase modulator is delivered.A PZT cylindrical phase modulator is designed,and the numerical simulation is conducted.Results prove that the PZT cylindrical phase modulator can effectively simulate leak acoustic emission signals when the frequency is lower than 25 KHz.

  6. Reservoir computing with a slowly modulated mask signal for preprocessing using a mutually coupled optoelectronic system

    Science.gov (United States)

    Tezuka, Miwa; Kanno, Kazutaka; Bunsen, Masatoshi

    2016-08-01

    Reservoir computing is a machine-learning paradigm based on information processing in the human brain. We numerically demonstrate reservoir computing with a slowly modulated mask signal for preprocessing by using a mutually coupled optoelectronic system. The performance of our system is quantitatively evaluated by a chaotic time series prediction task. Our system can produce comparable performance with reservoir computing with a single feedback system and a fast modulated mask signal. We showed that it is possible to slow down the modulation speed of the mask signal by using the mutually coupled system in reservoir computing.

  7. An analog modulation and demodulation method employing LVDT signal conditioner for fiber-optic interferometric sensors

    Science.gov (United States)

    Zhou, Kejiang; Rao, Qi; Zhang, Minjie; Hu, Keke; Ruan, Yefeng

    2017-09-01

    An analog method to modulate and demodulate fiber-optic interferometric sensors employing a linear variable differential transformer signal conditioner to generate sine modulation wave and demodulate phase-modulated signal from the photodetector’s output is presented in this letter. No external lock-in amplifiers or digital components are used in this design. All the necessary components for signal processing are integrated in a single analog electronic microchip AD698, which reduces the system’s complexity significantly. After implementation on an interferometric fiber-optic gyroscope as an example, this method demonstrates a bias stability of 0.063 deg h-1 (i.e. 0.220 µrad).

  8. Delta- Sigma Modulator with Signal Dependant Feedback Gain

    National Research Council Canada - National Science Library

    K.Diwakar; V.Vinoth Kumar

    2015-01-01

    Higher order Delta-Sigma Modulator (DSM) is basically an unstable system. The approximate conditions for stability cannot be used for the design of a DSM for industrial applications where risk is involved...

  9. Gap junction modulation by extracellular signaling molecules: the thymus model

    Directory of Open Access Journals (Sweden)

    Alves L.A.

    2000-01-01

    Full Text Available Gap junctions are intercellular channels which connect adjacent cells and allow direct exchange of molecules of low molecular weight between them. Such a communication has been described as fundamental in many systems due to its importance in coordination, proliferation and differentiation. Recently, it has been shown that gap junctional intercellular communication (GJIC can be modulated by several extracellular soluble factors such as classical hormones, neurotransmitters, interleukins, growth factors and some paracrine substances. Herein, we discuss some aspects of the general modulation of GJIC by extracellular messenger molecules and more particularly the regulation of such communication in the thymus gland. Additionally, we discuss recent data concerning the study of different neuropeptides and hormones in the modulation of GJIC in thymic epithelial cells. We also suggest that the thymus may be viewed as a model to study the modulation of gap junction communication by different extracellular messengers involved in non-classical circuits, since this organ is under bidirectional neuroimmunoendocrine control.

  10. A Study on Signal Group Processing of AUTOSAR COM Module

    Science.gov (United States)

    Lee, Jeong-Hwan; Hwang, Hyun Yong; Han, Tae Man; Ahn, Yong Hak

    2013-06-01

    In vehicle, there are many ECU(Electronic Control Unit)s, and ECUs are connected to networks such as CAN, LIN, FlexRay, and so on. AUTOSAR COM(Communication) which is a software platform of AUTOSAR(AUTomotive Open System ARchitecture) in the international industry standards of automotive electronic software processes signals and signal groups for data communications between ECUs. Real-time and reliability are very important for data communications in the vehicle. Therefore, in this paper, we analyze functions of signals and signal groups used in COM, and represent that functions of signal group are more efficient than signals in real-time data synchronization and network resource usage between the sender and receiver.

  11. 10 CFR 431.224 - Uniform test method for the measurement of energy consumption for traffic signal modules and...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Uniform test method for the measurement of energy consumption for traffic signal modules and pedestrian modules. 431.224 Section 431.224 Energy DEPARTMENT OF... measurement of energy consumption for traffic signal modules and pedestrian modules. (a) Scope. This section...

  12. Identification of melanoma biomarkers based on network modules by integrating the human signaling network with microarrays

    Directory of Open Access Journals (Sweden)

    Chunyun Huang

    2014-01-01

    Full Text Available Background: Melanoma is a leading cause of cancer death. Thus, accurate prognostic biomarkers that will assist rational treatment planning need to be identified. Methods: Microarray analysis of melanoma and normal tissue samples was performed to identify differentially expressed modules (DEMs from the signaling network and ultimately detect molecular markers to support histological examination. Network motifs were extracted from the human signaling network. Then, significant expression-correlation differential modules were identified by comparing the network module expression-correlation differential scores under normal and disease conditions using the gene expression datasets. Finally, we obtained DEMs by the Wilcoxon rank test and considered the average gene expression level in these modules as the classification features for diagnosing melanoma. Results: In total, 99 functional DEMs were identified from the signaling network and gene expression profiles. The area under the curve scores for cancer module genes, melanoma module genes, and whole network modules are 92.4%, 90.44%, and 88.45%, respectively. The classification efficiency rates for nonmodule features are 71.04% and 79.38%, which correspond to the features of cancer genes and melanoma cancer genes, respectively. Finally, we acquired six significant molecular biomarkers, namely, module 10 (CALM3, Ca 2+ , PKC, PDGFRA, phospholipase-g, PIB5PA, and phosphatidylinositol-3-kinase, module 14 (SRC, Src homology 2 domain-containing [SHC], SAM68, GIT1, transcription factor-4, CBLB, GRB2, VAV2, LCK, YES, PTCH2, downstream of tyrosine kinase [DOK], and KIT, module 16 (ELK3, p85beta, SHC, ZFYVE9, TGFBR1, TGFBR2, CITED1, SH3KBP1, HCK, DOK, and KIT, module 45 (RB, CCND3, CCNA2, CDK4, and CDK6, module 75 (PCNA, CDK4, and CCND1, and module 114 (PSD93, NMDAR, and FYN. Conclusion: We explored the gene expression profile and signaling network in a global view and identified DEMs that can be used as

  13. Colorless detection of NRZ-DPSK signals using electro-optic clock re-modulation

    DEFF Research Database (Denmark)

    Zsigri, Beata; Tokle, Torger; Peucheret, Christophe

    2010-01-01

    Wavelength-independent detection of NRZ-DPSK signals is proposed and demonstrated at 43 Gbit/s. The scheme relies on re-modulation of the incoming NRZ-DPSK signal with a recovered electrical clock. Good performance is obtained after dispersion managed transmission.......Wavelength-independent detection of NRZ-DPSK signals is proposed and demonstrated at 43 Gbit/s. The scheme relies on re-modulation of the incoming NRZ-DPSK signal with a recovered electrical clock. Good performance is obtained after dispersion managed transmission....

  14. A Two-Dimensional Signal Space for Intensity-Modulated Channels

    CERN Document Server

    Karout, Johnny; Kschischang, Frank R; Agrell, Erik

    2012-01-01

    A two-dimensional signal space for intensity- modulated channels is presented. Modulation formats using this signal space are designed to maximize the minimum distance between signal points while satisfying average and peak power constraints. The uncoded, high-signal-to-noise ratio, power and spectral efficiencies are compared to those of the best known formats. The new formats are simpler than existing subcarrier formats, and are superior if the bandwidth is measured as 90% in-band power. Existing subcarrier formats are better if the bandwidth is measured as 99% in-band power.

  15. Direct UV written Michelson interferometer for RZ signal generation using phase-to-intensity modulation conversion

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Geng, Yan; Zsigri, Beata

    2005-01-01

    An integrated Michelson delay interferometer structure making use of waveguide gratings as reflective elements is proposed and fabricated by direct ultraviolet writing. Successful return-to-zero alternate-mark-inversion signal generation using phase-to-intensity modulation conversion...

  16. Signal Modulation of Super Read Only Memory with Thermally Activated Aperture Model

    Science.gov (United States)

    Kim, June Seo; Kwak, Keumcheol; You, Chun-Yeol

    2008-07-01

    We describe the signal modulation of super read only memory (ROM) with thermally activated aperture model using a three-dimensional finite-difference time-domain method. The thermally activated aperture is modeled using a spatially varied refractive indices of the GeSbTe layer. No meaningful signal modulation is observed without thermally activated aperture below the resolution limit of 120 nm. When we open the thermally activated aperture by considering the temperature dependence of the refractive indices in the GeSbTe layer, the 2.8 and 1.7% signal modulations are observed for 120 and 80 nm pits, respectively. The experimentally observed signal modulation under the resolution limit can be explained using the thermally activated aperture model.

  17. Effect of Physical Exercise on the Febrigenic Signaling is Modulated by Preoptic Hydrogen Sulfide Production

    National Research Council Canada - National Science Library

    Nogueira, Jonatas E; Soriano, Renato N; Fernandez, Rodrigo A. R; Francescato, Heloísa D. C; Saia, Rafael S; Coimbra, Terezila M; Antunes-Rodrigues, José; Branco, Luiz G. S

    2017-01-01

    ...) of the hypothalamus modulates the febrigenic signaling differently in sedentary and trained rats. Besides H2S production rate and protein expressions of H2S-related synthases cystathionine [Beta]-synthase (CBS...

  18. Quantitative Measurement of Longitudinal and Transverse Cross-Relaxation Rates: An Application to the Analysis of the Internal Dynamics of Ranalexin in Water and Trifluoroethanol

    Science.gov (United States)

    Malliavin, T. E.; Desvaux, H.; Aumelas, A.; Chavanieu, A.; Delsuc, M. A.

    1999-09-01

    We describe a quantitative processing method which gives access to the longitudinal and transverse cross-relaxation rates from off-resonance ROESY intensities. This method takes advantage of the dependence of the off-resonance ROESY experiments at any mixing time and any spin-lock angle θ on two relaxation matrices, the longitudinal and the transverse ones. This allows one to take into account multistep magnetization transfers even if the measurements are performed only at one or two mixing times. The ratio of the longitudinal to transverse cross-relaxation rates can then be used as a local indicator of the internal dynamics, without assuming a structure or a model of motion. After validation of this processing method by numerical simulations, it is applied to the analysis of the dynamics of the peptide ranalexin dissolved in pure water and in water/TFE.

  19. Investigation of Annual Modulation Signal from Radon Induced Gamma Rays

    Science.gov (United States)

    Zhang, Chao; Mei, Dongming

    2015-10-01

    The phenomenon of annual modulation is believed to be one of the signatures induced by Weakly Interacting Massive Particles(WIMPs) through elastic scattering off nucleus in the target for direct dark matter searches. Both DAMA and CoGeNT experiments have claimed the discovery of dark matter in terms of annual modulation while many other experiments have ruled out the entire claimed region. However, the sources that caused the annual modulation in DAMA and CoGeNT are still unknown which need to be investigated. Annual modulations of Radon at underground sites are reported by many experiments. As a potential source, we investigate (alpha, gamma) reactions, induced by radon decay chain, occurring on the surface of those common shielding materials and explain how this background annual modulation may mimic dark matter signature. This work is supported by NSF in part by the NSF PHY-0758120, DOE Grant DE-FG02-10ER46709, and the State of South Dakota.

  20. p75 neurotrophin receptor signaling: mechanisms for neurotrophic modulation of cell stress?

    Science.gov (United States)

    Dobrowsky, R T; Carter, B D

    2000-08-01

    The recent recognition that the p75 neurotrophin receptor, p75((NTR)), can induce apoptotic signals has contributed to the perception that it acts primarily as a death receptor. Although the molecular mechanisms of p75(NTR) signaling remain to be fully characterized, many of the currently identified pathways activated by p75(NTR) may be generally characterized as stress response signals. This review describes recent advances in identifying the molecular components involved in p75(NTR) signal transduction and suggests that p75(NTR) signaling may more aptly serve as a general mechanism for the transduction and modulation of stress signals.

  1. Signal recognition and parameter estimation of BPSK-LFM combined modulation

    Science.gov (United States)

    Long, Chao; Zhang, Lin; Liu, Yu

    2015-07-01

    Intra-pulse analysis plays an important role in electronic warfare. Intra-pulse feature abstraction focuses on primary parameters such as instantaneous frequency, modulation, and symbol rate. In this paper, automatic modulation recognition and feature extraction for combined BPSK-LFM modulation signals based on decision theoretic approach is studied. The simulation results show good recognition effect and high estimation precision, and the system is easy to be realized.

  2. Electrical Motor Current Signal Analysis using a Modulation Signal Bispectrum for the Fault Diagnosis of a Gearbox Downstream

    Science.gov (United States)

    Haram, M.; Wang, T.; Gu, F.; Ball, A. D.

    2012-05-01

    Motor current signal analysis has been an effective way for many years of monitoring electrical machines themselves. However, little work has been carried out in using this technique for monitoring their downstream equipment because of difficulties in extracting small fault components in the measured current signals. This paper investigates the characteristics of electrical current signals for monitoring the faults from a downstream gearbox using a modulation signal bispectrum (MSB), including phase effects in extracting small modulating components in a noisy measurement. An analytical study is firstly performed to understand amplitude, frequency and phase characteristics of current signals due to faults. It then explores the performance of MSB analysis in detecting weak modulating components in current signals. Experimental study based on a 10kw two stage gearbox, driven by a three phase induction motor, shows that MSB peaks at different rotational frequencies can be based to quantify the severity of gear tooth breakage and the degrees of shaft misalignment. In addition, the type and location of a fault can be recognized based on the frequency at which the change of MSB peak is the highest among different frequencies.

  3. A novel Modulation Topology for Power Converters utilizing Multiple Carrier Signals

    DEFF Research Database (Denmark)

    Knott, Arnold; Pfaffinger, Gerhard; Andersen, Michael Andreas E.

    2008-01-01

    Power converters are known to generate spectral components in the range of interest of electromagnetic compatibility measurements. Common approaches to manipulate some selected components in these frequency ranges are shown here. These approaches add components to the input signal of the modulator...... to derive a slightly varied spectrum. To achieve a rectangular output signal, those modulators use a triangular or saw tooth carrier signal. A novel family of modulators is shown here, using more than one carrier signal to obtain a completely changed spectrum while maintaining the rectangular shaped...... waveform at the output. The multiple carriers are fed into multiple comparators and their outputs are intelligently combined by logic gates to get a single signal to drive one power stage of any type of converter. This commutation distinguishes between the four members of the novel family: the first one...

  4. Mitigation of signal quality degradation induced by PMD using synchronous modulation

    Institute of Scientific and Technical Information of China (English)

    Li Huo(霍力); Yanfu Yang(杨彦甫); Caiyun Lou(娄采云); Hejun Yao(姚和军); Xiaomin Song(宋晓旻); Yizhi Gao(高以智)

    2004-01-01

    In-line synchronous modulation as a way of mitigating the signal quality degradation induced by polar ization mode dispersion(PMD)was experimentally studied using 10-Gb/s return to zero signal.Bit error rate of the degraded signal and the synchronously modulated signal under the differential group delay(DGD)values of 10,20,34,and 70 ps was measured and compared.The experimental results showed that in-line synchronous modulation is useful to mitigate the signal quality degeneration induced by PMD.1-dB power penalty reduction was obtained even when the PMD was as high as 70% of the bit interval.The limitation of method is also discussed.

  5. Signal modulating noise effect in bistable stochastic resonance systems and its analog simulation

    Institute of Scientific and Technical Information of China (English)

    XIAO Fang-hong; YAN Gui-rong; XIE Shi-cheng

    2006-01-01

    The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.

  6. BPSK optical mm-wave signal generation by septupling frequency via a single optical phase modulator

    Science.gov (United States)

    Wu, Peng; Ma, Jianxin

    2016-09-01

    In this paper, we have proposed a novel and simple scheme to generate the BPSK optical millimeter wave (MMW) signal with frequency septupling by using an optical phase modulator (PM) and a wavelength selective switch (WSS). In this scheme, the PM is driven by a radio frequency (RF) BPSK signal at the optimized modulation index of 4.89 to assure the 4th and 3rd-order sidebands have equal amplitudes. An wavelength selective switch (WSS) is used to abstract the -4th and +3rd-order sidebands from the spectrum generated by RF BPSK signal modulating the lightwave to form the BPSK optical MMW signal with frequency septupling the driving RF signal. In these two tones, only the +3rd-order sideband bears the BPSK signal while the -4th-order sideband is unmodulated since the phase information is canceled by the even times multiplication of the phase of BPSK signal. The MMW signal can avoid the pulse walk-off effect and the amplitude fading effect caused by the fiber chromatic dispersion. By adjusting the modulation index to assure the two tones have equal amplitude, the generated optical MMW signal has the maximal opto-electrical conversion efficiency and good transmission performance.

  7. [Role of interoceptive signalization in modulating emotional-behavioral responses].

    Science.gov (United States)

    Emel'ianenko, I V; Raĭtses, V S

    1976-03-01

    Chronic experiments were conducted on rabbits; electrodes were implanted into the deep structures of the brain. Stimulation of gastric receptors led to modulation of the emotional-behavioristic reactions induced by electric stimulation of the hypothalamus, the amygdala and the hypocampus. The effect depended on the intensity of interoceptive stimulation and peculiarities of the emotional reaction with own cerebral control systems.

  8. A 7-8 GHz serrodyne modulator in SiGe for MIMO signal generation

    NARCIS (Netherlands)

    Withagen, Johan C.J.G.; Annema, A.J.; Nauta, B.; Vliet, van F.E.

    2014-01-01

    An 8-bit 360o sawtooth modulated phase shifter is used to apply very small frequency offsets to RF signals between 7 and 8 GHz. Offsets between 6 Hz and 10MHz can be obtained. Such frequency offsets can be used to generate orthogonal signals, which are required in e.g. MIMO applications. Each undesi

  9. Digital coherent receiver for subcarrier multiplexed phase modulated radio-over-fibre signals

    DEFF Research Database (Denmark)

    Zibar, Darko; Larsen, Knud J.; Tafur Monroy, Idelfonso

    2009-01-01

    Digital coherent detection of multi-channel subcarrier multiplexed optically phase-modulated radio-over-fibre signals is experimentally demonstrated. Successful detection after transmission over a 40 km long fibre link of four or five 25 Mbaud BPSK/QPSK subcarrier channels in 5 GHz bandwidth...... is demonstrated using offline digital signal processing....

  10. Modulation of β-catenin signaling by glucagon receptor activation.

    Directory of Open Access Journals (Sweden)

    Jiyuan Ke

    Full Text Available The glucagon receptor (GCGR is a member of the class B G protein-coupled receptor family. Activation of GCGR by glucagon leads to increased glucose production by the liver. Thus, glucagon is a key component of glucose homeostasis by counteracting the effect of insulin. In this report, we found that in addition to activation of the classic cAMP/protein kinase A (PKA pathway, activation of GCGR also induced β-catenin stabilization and activated β-catenin-mediated transcription. Activation of β-catenin signaling was PKA-dependent, consistent with previous reports on the parathyroid hormone receptor type 1 (PTH1R and glucagon-like peptide 1 (GLP-1R receptors. Since low-density-lipoprotein receptor-related protein 5 (Lrp5 is an essential co-receptor required for Wnt protein mediated β-catenin signaling, we examined the role of Lrp5 in glucagon-induced β-catenin signaling. Cotransfection with Lrp5 enhanced the glucagon-induced β-catenin stabilization and TCF promoter-mediated transcription. Inhibiting Lrp5/6 function using Dickkopf-1(DKK1 or by expression of the Lrp5 extracellular domain blocked glucagon-induced β-catenin signaling. Furthermore, we showed that Lrp5 physically interacted with GCGR by immunoprecipitation and bioluminescence resonance energy transfer assays. Together, these results reveal an unexpected crosstalk between glucagon and β-catenin signaling, and may help to explain the metabolic phenotypes of Lrp5/6 mutations.

  11. A Flexible Modulation Scheme Design for C-Band GNSS Signals

    Directory of Open Access Journals (Sweden)

    Rui Xue

    2015-01-01

    Full Text Available Due to the spectrum congestion of current navigation signals in L-band, C-band has been taken into consideration as a candidate frequency band for global navigation satellite system (GNSS. As is known, modulation scheme is the core part of signal structure, and how to design a modulation waveform that could make full use of narrow bandwidth 20 MHz and satisfy the constraint condition of frequency compatibility in C-band is the main research content of this paper. In view of transmission characteristics and constraint condition of compatibility in C-band, multi-h continuous phase modulation (CPM is proposed as a candidate modulation scheme. Then the classical channel capacity estimation and a comprehensive evaluation criterion for GNSS modulation signals are employed to assess the proposed scheme in the aspects of the capacity over additive white Gaussian noise (AWGN, tracking accuracy, multipath mitigation, antijamming, and so on. Simulation results reveal that, through optimizing the number and size of modulation indexes, the flexible scheme could offer better performance in terms of code tracking, multipath mitigation, and antijamming compared with other candidates such as MSK and GMSK while maintaining high band efficiency and moderate implementation complexity of receiver. Moreover, this paper also provides a reference for next generation modulation signals in C-band.

  12. Low-frequency analog signal distribution on digital photonic networks by optical delta-sigma modulation

    Science.gov (United States)

    Kanno, Atsushi; Kawanishi, Tetsuya

    2013-12-01

    We propose a delta-sigma modulation scheme for low- and medium-frequency signal transmission in a digital photonic network system. A 10-Gb/s-class optical transceiver with a delta-sigma modulator utilized as a high-speed analog-to-digital converter (ADC) provides a binary optical signal. On the signal reception side, a low-cost and slow-speed photonic receiver directly converts the binary signal into an analog signal at frequencies from several hundreds of kilohertz several tens of megahertz. Further, by using a clock and data recovery circuit at the receiver to reduce jitters, the single-sideband phase noise of the generated signals can be significantly reduced.

  13. Lrp4 modulates extracellular integration of cell signaling pathways in development.

    Directory of Open Access Journals (Sweden)

    Atsushi Ohazama

    Full Text Available The extent to which cell signaling is integrated outside the cell is not currently appreciated. We show that a member of the low-density receptor-related protein family, Lrp4 modulates and integrates Bmp and canonical Wnt signalling during tooth morphogenesis by binding the secreted Bmp antagonist protein Wise. Mouse mutants of Lrp4 and Wise exhibit identical tooth phenotypes that include supernumerary incisors and molars, and fused molars. We propose that the Lrp4/Wise interaction acts as an extracellular integrator of epithelial-mesenchymal cell signaling. Wise, secreted from mesenchyme cells binds to BMP's and also to Lrp4 that is expressed on epithelial cells. This binding then results in the modulation of Wnt activity in the epithelial cells. Thus in this context Wise acts as an extracellular signaling molecule linking two signaling pathways. We further show that a downstream mediator of this integration is the Shh signaling pathway.

  14. Insulin signaling genes modulate nicotine-induced behavioral responses in Caenorhabditis elegans.

    Science.gov (United States)

    Wescott, Seth A; Ronan, Elizabeth A; Xu, X Z Shawn

    2016-02-01

    Insulin signaling has been suggested to modulate nicotine dependence, but the underlying genetic evidence has been lacking. Here, we used the nematode, Caenorhabditis elegans, to investigate whether genetic alterations in the insulin signaling pathway affect behavioral responses to nicotine. For this, we challenged drug-naive C. elegans with an acute dose of nicotine (100 μmol/l) while recording changes in their locomotion speed. Although nicotine treatment stimulated locomotion speed in wild-type C. elegans, the same treatment reduced locomotion speed in mutants defective in insulin signaling. This phenotype could be suppressed by mutations in daf-16, a gene encoding a FOXO transcription factor that acts downstream of insulin signaling. Our data suggest that insulin signaling genes, daf-2, age-1, pdk-1, akt-1, and akt-2, modulate behavioral responses to nicotine in C. elegans, indicating a genetic link between nicotine behavior and insulin signaling.

  15. Casein kinase Iepsilon modulates the signaling specificities of dishevelled.

    Science.gov (United States)

    Cong, Feng; Schweizer, Liang; Varmus, Harold

    2004-03-01

    Wnt signaling is critical to many aspects of development, and aberrant activation of the Wnt signaling pathway can cause cancer. Dishevelled (Dvl) protein plays a central role in this pathway by transducing the signal from the Wnt receptor complex to the beta-catenin destruction complex. Dvl also plays a pivotal role in the planar cell polarity pathway that involves the c-Jun N-terminal kinase (JNK). How functions of Dvl are regulated in these two distinct pathways is not clear. We show that deleting the C-terminal two-thirds of Dvl, which includes the PDZ and DEP domains and is essential for Dvl-induced JNK activation, rendered the molecule a much more potent activator of the beta-catenin pathway. We also found that casein kinase Iepsilon (CKIepsilon), a previously identified positive regulator of Wnt signaling, stimulated Dvl activity in the Wnt pathway, but dramatically inhibited Dvl activity in the JNK pathway. Consistent with this, overexpression of CKIepsilon in Drosophila melanogaster stimulated Wnt signaling and disrupted planar cell polarity. We also observed a correlation between the localization and the signaling activity of Dvl in the beta-catenin pathway and the JNK pathway. Furthermore, by using RNA interference, we demonstrate that the Drosophila CKIepsilon homologue Double time positively regulates the beta-catenin pathway through Dvl and negatively regulates the Dvl-induced JNK pathway. We suggest that CKIepsilon functions as a molecular switch to direct Dvl from the JNK pathway to the beta-catenin pathway, possibly by altering the conformation of the C terminus of Dvl.

  16. The Utilization of Novel Bandpass Sigma-delta Modulator for Capacitance Pressure Sensor Signal Processing

    Directory of Open Access Journals (Sweden)

    L. Michaeli

    2008-12-01

    Full Text Available The paper deals with a novel approach to processing of pressure sensor signals. A bandpass sigma-delta modulator is used for this purpose. This technique is relatively new and it is not used widely, because this kind of modulator is usually utilized for wireless and video applications. Since the bandpass sigma-delta modulator works within its defined band it is resistant to offsets of its sub-circuits. The main stages of this modulator are implemented by means of switched-capacitor (SC technique. The article presents the basic ideas of this approach and simulation results of the first order of ideal and real modulator. The paper also shows the design of the phase locked loop (PLL block for synchronization of sensor signal and modulator driving signal. The simple evaluation board was fabricated for confirmation of the proposed principle. Also shown are the results of the chip testing, the modulator layout and the design and test results of the second order of bandpass sigma-delta modulator briefly.

  17. Stochastic resonance of bias signal-modulated noise in a single-mode laser

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Cao Li; Wu Da-Jin

    2004-01-01

    Stochastic resonance (SR) for bias signal modulation is studied in a single-mode laser system. By investigating a gain-noise model driven by correlated pump noise and quantum noir, we find that, whether the correlation coefficient between both the noises is positive or negative, SR always appears in the dependence of signal-to-noise ratio (SNR) upon the noise correlation time and the frequency of the modulation signal. However, only when the correlation coefficient between both noises is negative can SR occur in the dependence of SNR upon the quantum noise intensity and pump noise intensity, while when the correlation coefficient between both noises is positive, it shows monotonically.

  18. Phase Regeneration of a BPSK Data Signal Using a Lithium Niobate Phase Modulator

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Da Ros, Francesco; Galili, Michael

    2015-01-01

    We propose a scheme for phase regeneration of an optical binary phase shift keying (BPSK) data signal using a Lithium Niobate (LiNbO3) phase modulator. The scheme is based on heterodyne detection of the BPSK data signal with a continuous wave local oscillator (CW-LO). Carrier recovery...... is then achieved in the electrical domain using a ×2 frequency-multiplier and a narrow-band filtering scheme. Subsequently, a superposition of the recovered carrier and the heterodyne detected data signal is used to modulate the CW-LO in a LiNbO3 phase modulator. The result is a parametric mixing process...... in the optical domain, leading to a phase-regenerated BPSK data signal by the coherent superposition with a phase-inverted copy. The proposed scheme constitutes a compact and stable setup, where active phase-stabilization of the electrical data- and carrier-paths can potentially be avoided. An analytical...

  19. Shh Signaling through the Primary Cilium Modulates Rat Oligodendrocyte Differentiation.

    Science.gov (United States)

    Falcón-Urrutia, Paulina; Carrasco, Carlos M; Lois, Pablo; Palma, Veronica; Roth, Alejandro D

    2015-01-01

    Primary Cilia (PC) are a very likely place for signal integration where multiple signaling pathways converge. Two major signaling pathways clearly shown to signal through the PC, Sonic Hedgehog (Shh) and PDGF-Rα, are particularly important for the proliferation and differentiation of oligodendrocytes, suggesting that their interaction occurs in or around this organelle. We identified PC in rat oligodendrocyte precursor cells (OPCs) and found that, while easily detectable in early OPCs, PC are lost as these cells progress to terminal differentiation. We confirmed the interaction between these pathways, as cyclopamine inhibition of Hedgehog function impairs both PDGF-mediated OPC proliferation and Shh-dependent cell branching. However, we failed to detect PDGF-Rα localization into the PC. Remarkably, ciliobrevin-mediated disruption of PC and reduction of OPC process extension was counteracted by recombinant Shh treatment, while PDGF had no effect. Therefore, while PDGF-Rα-dependent OPC proliferation and survival most probably does not initiate at the PC, still the integrity of this organelle and cilium-centered pathway is necessary for OPC survival and differentiation.

  20. Detecting Fleeting MRI Signals with Frequency-Modulated Pulses

    Science.gov (United States)

    Kobayashi, Naoharu; Idiyatullin, Djaudat; Corum, Curtis; Moeller, Steen; Chamberlain, Ryan; O'Connell, Robert; Nixdorf, Donald R.; Garwood, Michael

    2012-01-01

    We describe a fundamentally different approach to MRI referred to as SWIFT (sweep imaging with Fourier transformation). SWIFT exploits time-shared RF excitation and signal acquisition, allowing capture of signal from spins with extremely short transverse relaxation time, T2*. The MR signal is acquired in gaps inserted into a broadband frequency-swept excitation pulse, which results in acquisition delays of only 1 – 2 microseconds. In SWIFT, 3D k-space is sampled in a radial manner, whereby one projection of the object is acquired in the gaps of each frequency-swept pulse, allowing a repetition time (TR) on the order of the pulse length (typically 1 – 3 milliseconds). Since the orientation of consecutive projections varies in a smooth manner (i.e., only small increments in the values of the x, y, z gradients occur from view to view), SWIFT scanning is close to inaudible and is insensitive to gradient timing errors and eddy currents. SWIFT images can be acquired in scan times similar to and sometimes faster than conventional 3D gradient echo techniques. With its ability to capture signals from ultrashort T2* spins, SWIFT promises to expand the role of MRI in areas of research where MRI previously played no or negligible role. In this article, we show wood and tooth images obtained with SWIFT as examples of materials with ultrashort T2*. Early experience suggests SWIFT can play a role in materials science and porous media research. PMID:22661791

  1. Neurofibromin Regulation of ERK Signaling Modulates GABA Release and Learning

    NARCIS (Netherlands)

    Y. Cui (Yijun); R.M. Costa (Rui); G.G. Murphy (Geoffrey); Y. Elgersma (Ype); Y. Zhu (Yuan); D.H. Gutmann (David); L.F. Parada (Luis); I. Mody (Istvan); A.J. Silva (Alcino)

    2008-01-01

    textabstractWe uncovered a role for ERK signaling in GABA release, long-term potentiation (LTP), and learning, and show that disruption of this mechanism accounts for the learning deficits in a mouse model for learning disabilities in neurofibromatosis type I (NF1). Our results demonstrate that neur

  2. A Processing Technique for OFDM-Modulated Wideband Radar Signals

    NARCIS (Netherlands)

    Tigrek, R.F.

    2010-01-01

    The orthogonal frequency division multiplexing (OFDM) is a multicarrier spread-spectrum technique which finds wide-spread use in communications. The OFDM pulse compression method that utilizes an OFDM communication signal for radar tasks has been developed and reported in this dissertation. Using th

  3. Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

    Science.gov (United States)

    Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R

    2000-09-01

    Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

  4. Diurnal modulation signal from dissipative hidden sector dark matter

    Directory of Open Access Journals (Sweden)

    R. Foot

    2015-09-01

    Full Text Available We consider a simple generic dissipative dark matter model: a hidden sector featuring two dark matter particles charged under an unbroken U(1′ interaction. Previous work has shown that such a model has the potential to explain dark matter phenomena on both large and small scales. In this framework, the dark matter halo in spiral galaxies features nontrivial dynamics, with the halo energy loss due to dissipative interactions balanced by a heat source. Ordinary supernovae can potentially supply this heat provided kinetic mixing interaction exists with strength ϵ∼10−9. This type of kinetically mixed dark matter can be probed in direct detection experiments. Importantly, this self-interacting dark matter can be captured within the Earth and shield a dark matter detector from the halo wind, giving rise to a diurnal modulation effect. We estimate the size of this effect for detectors located in the Southern hemisphere, and find that the modulation is large (≳10% for a wide range of parameters.

  5. Diurnal modulation signal from dissipative hidden sector dark matter

    CERN Document Server

    Foot, R

    2014-01-01

    We consider a simple generic dissipative dark matter model: a hidden sector featuring two dark matter particles charged under an unbroken $U(1)'$ interaction. Previous work has shown that such a model has the potential to explain dark matter phenomena on both large and small scales. In this framework, the dark matter halo in spiral galaxies features nontrivial dynamics, with the halo energy loss due to dissipative interactions balanced by a heat source. Ordinary supernovae can potentially supply this heat provided kinetic mixing interaction exists with strength $\\epsilon \\sim 10^{-9}$. This type of kinetically mixed dark matter can be probed in direct detection experiments. Importantly, this self-interacting dark matter can be captured within the Earth and shield a dark matter detector from the halo wind, giving rise to a diurnal modulation effect. We estimate the size of this effect for detectors located in the Southern hemisphere, and find that the modulation is large ($\\gtrsim 10\\%$) for a wide range of pa...

  6. Modulation of host-cell MAPkinase signaling during fungal infection

    OpenAIRE

    2015-01-01

    Fungal infections contribute substantially to human suffering and mortality. The interaction between fungal pathogens and their host involves the invasion and penetration of the surface epithelium, activation of cells of the innate immune system and the generation of an effective response to block infection. Numerous host-cell signaling pathways are activated during fungal infection. This review will focus on the main fungal pathogens Aspergillus fumigatus, Candida albicans and Cryptococcus n...

  7. Methods of Interference-Free Reception of Frequency Modulated and Phase Modulated Signals,

    Science.gov (United States)

    1979-08-23

    340s; t:, =400 . Here the signal/noise ratio in the Af.x, band is plotted on the abscissa, the ratio of the signal’s power (without predistortion and...a band ratio of Afw,x,Afw,=6,5 dB. It is important to note that at the point having a zero measuring level which is psophometric with predistortions ...coefficient (P) also. IIf there is predistortion of the spectrum for the group signal in the lower telephone channel in the subthreshold region the signal

  8. High expression of G-protein signaling modulator 2 in hepatocellular carcinoma facilitates tumor growth and metastasis by activating the PI3K/AKT signaling pathway.

    Science.gov (United States)

    He, Xiao-Qin; Zhang, Yue-Feng; Yu, Jia-Jun; Gan, Yuan-Yuan; Han, Na-Na; Zhang, Mei-Xia; Ge, Wei; Deng, Jun-Jian; Zheng, Yong-Fa; Xu, Xi-Ming

    2017-03-01

    The aim of this study was to investigate the role of G-protein signaling modulator 2 in the carcinogenesis and progression of hepatocellular carcinoma. We previously showed that G-protein signaling modulator 2 was upregulated in hepatitis B virus-related hepatocellular carcinoma tissues through a hierarchical clustering analysis. With this study, we first assessed the expression pattern of G-protein signaling modulator 2 in hepatocellular carcinoma specimens and adjacent noncancerous tissues; clinical data were analyzed, along survival times, utilizing the Kaplan-Meier method. Moreover, the functions of G-protein signaling modulator 2 were examined using small-interfering RNAs in vitro. The results showed that G-protein signaling modulator 2 was clearly overexpressed in hepatocellular carcinoma tissues and cell lines and that the G-protein signaling modulator 2 expression level was related to tumor size and hepatitis B virus infection. Furthermore, G-protein signaling modulator 2 knockdown studies suggested that G-protein signaling modulator 2 accelerates cell growth, cell cycle, migration, and invasion and inhibits apoptosis, acting as an oncogene in hepatocellular carcinoma. Western blotting indicated that silencing of G-protein signaling modulator 2 in HepG2 and SMMC-7721 cells increased the expression levels of Bax, caspase-3, and E-cadherin, while notably suppressing the cyclin-dependent kinase 4, cyclin-dependent kinase 6, CyclinD1, Snail1, Vimentin, and matrix metallopeptidase 9 expression levels, compared with that in the control groups. In addition, we found that G-protein signaling modulator 2 can affect the expression of key proteins involved in protein kinase B activation. In conclusion, high expression of G-protein signaling modulator 2 was involved in the pathological processes of hepatocellular carcinoma through activation of the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, which may provide an attractive potential diagnostic

  9. Use of modulated excitation signals in ultrasound. Part I: Basic concepts and expected benefits

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    This paper, the first from a series of three papers on the application of coded excitation signals in medical ultrasound, discusses the basic principles and ultrasound-related problems of pulse compression. The concepts of signal modulation and matched filtering are given, and a simple model...... of attenuation relates the matched filter response with the ambiguity function, known from radar. Based on this analysis and the properties of the ambiguity function, the selection of coded waveforms suitable for ultrasound imaging is discussed. It is shown that linear frequency modulation (FM) signals have...... the best and most robust features for ultrasound imaging. Other coded signals such as nonlinear FM and binary complementary Golay codes also have been considered and characterized in terms of signal-to-noise ratio (SNR) and sensitivity to frequency shifts. Using the simulation program Field II, it is found...

  10. A New Two-Branch Amplification Architecture and its Application with Various Modulated Signals

    Institute of Scientific and Technical Information of China (English)

    W. Hamdane; A. B. Kouki; F. Gagnon

    2011-01-01

    This paper proposes a new two-branch amplification architecture that combines baseband signal decomposition with RF front-end optimization. In the proposed architecture, the filtered modulated signals are separated into two components that are then amplified independently and combined to regenerate an amplified version of the original signal. A branch with an efficient amplifier transmits a low-varying envelope signal that contains the main part of the information. Another branch amplifies the residual portion of the signal. The baseband decomposition and parameters of the RF part are optimized to find the configuration that gives the best power efficiency and linearity. For M-ary quadrature amplitude modulation (M-QAM) signals, this technique is limited in terms of power efficiency. However, for filtered continuous phase modulation (CPM) signals, especially for minimum shift keying (MSK) and Gaussian MSK (GMSK) signals, high power efficiency can be achieved with no significant impact on the overall linearity. The results show that this technique gives better performance than the single-ended ctass-B amplifier.

  11. Method for Signal Processing of Electric Field Modulation Sensor in a Conductive Environment

    Directory of Open Access Journals (Sweden)

    O. I. Miseyk

    2015-01-01

    Full Text Available In investigating the large waters and deep oceans the most promising are modulation sensors for measuring electric field in a conducting environment in a very low frequency range in devices of autonomous or non-autonomous vertical sounding. When using sensors of this type it is necessary to solve the problem of enhancement and measurement of the modulated signal from the baseband noise.The work analyses hydrodynamic and electromagnetic noise at the input of transducer with "rotating" sensitive axis. By virtue of matching the measuring electrodes with the signal processing circuit a conclusion has been drawn that the proposed basic model of a transducer with "rotating” sensitive axis is the most efficient in terms of enhancement and measurement of modulated signal from the baseband noise. It has been shown that it is undesirable for transducers to have the rotation of electrodes resulting, in this case, in arising noise to be synchronously changed with transducer rotation frequency (modulation frequency. This will complicate the further signal-noise enhancement later in their processing.The paper justifies the choice of demodulation output signal, called synchronous demodulation using a low-pass filter with a cutoff frequency much lower than the carrier frequency to provide an output signal in the range of very low frequency and dc electric fields.The paper offers an original circuit to process the signals taken from the modulation sensor with "rotating" measurement base. This circuit has advantages over the earlier known circuits for measuring electric fields in a conducting (marine environment in the ultralow frequency range of these fields in terms of sensitivity and measuring accuracy of modulation sensors.

  12. Cannabinoid receptor 2 signaling does not modulate atherogenesis in mice.

    Directory of Open Access Journals (Sweden)

    Florian Willecke

    Full Text Available BACKGROUND: Strong evidence supports a protective role of the cannabinoid receptor 2 (CB(2 in inflammation and atherosclerosis. However, direct proof of its involvement in lesion formation is lacking. Therefore, the present study aimed to characterize the role of the CB(2 receptor in Murine atherogenesis. METHODS AND FINDINGS: Low density lipoprotein receptor-deficient (LDLR(-/- mice subjected to intraperitoneal injections of the selective CB(2 receptor agonist JWH-133 or vehicle three times per week consumed high cholesterol diet (HCD for 16 weeks. Surprisingly, intimal lesion size did not differ between both groups in sections of the aortic roots and arches, suggesting that CB(2 activation does not modulate atherogenesis in vivo. Plaque content of lipids, macrophages, smooth muscle cells, T cells, and collagen were also similar between both groups. Moreover, CB(2 (-/-/LDLR(-/- mice developed lesions of similar size containing more macrophages and lipids but similar amounts of smooth muscle cells and collagen fibers compared with CB(2 (+/+/LDLR(-/- controls. While JWH-133 treatment reduced intraperitoneal macrophage accumulation in thioglycollate-elicited peritonitis, neither genetic deficiency nor pharmacologic activation of the CB(2 receptor altered inflammatory cytokine expression in vivo or inflammatory cell adhesion in the flow chamber in vitro. CONCLUSION: Our study demonstrates that both activation and deletion of the CB(2 receptor do not relevantly modulate atherogenesis in mice. Our data do not challenge the multiple reports involving CB(2 in other inflammatory processes. However, in the context of atherosclerosis, CB(2 does not appear to be a suitable therapeutic target for reduction of the atherosclerotic plaque.

  13. Moxonidine modulates cytokine signalling and effects on cardiac cell viability.

    Science.gov (United States)

    Aceros, Henry; Farah, Georges; Noiseux, Nicolas; Mukaddam-Daher, Suhayla

    2014-10-05

    Regression of left ventricular hypertrophy and improved cardiac function in SHR by the centrally acting imidazoline I1-receptor agonist, moxonidine, are associated with differential actions on circulating and cardiac cytokines. Herein, we investigated cell-type specific I1-receptor (also known as nischarin) signalling and the mechanisms through which moxonidine may interfere with cytokines to affect cardiac cell viability. Studies were performed on neonatal rat cardiomyocytes and fibroblasts incubated with interleukin (IL)-1β (5 ng/ml), tumor necrosis factor (TNF)-α (10 ng/ml), and moxonidine (10(-7) and 10(-5) M), separately and in combination, for 15 min, and 24 and 48 h for the measurement of MAPKs (ERK1/2, JNK, and p38) and Akt activation and inducible NOS (iNOS) expression, by Western blotting, and cardiac cell viability/proliferation and apoptosis by flow cytometry, MTT assay, and Live/Dead assay. Participation of imidazoline I1-receptors and the signalling proteins in the detected effects was identified using imidazoline I1-receptor antagonist and signalling protein inhibitors. The results show that IL-1β, and to a lower extent, TNF-α, causes cell death and that moxonidine protects against starvation- as well as IL-1β -induced mortality, mainly by maintaining membrane integrity, and in part, by improving mitochondrial activity. The protection involves activation of Akt, ERK1/2, p38, JNK, and iNOS. In contrast, moxonidine stimulates basal and IL-1β-induced fibroblast mortality by mechanisms that include inhibition of JNK and iNOS. Thus, apart from their actions on the central nervous system, imidazoline I1-receptors are directly involved in cardiac cell growth and death, and may play an important role in cardiovascular diseases associated with inflammation.

  14. A novel duplex WDM-PON with DPSK modulated downstream and re-modulation of the downlink signal for OOKupstream

    Institute of Scientific and Technical Information of China (English)

    Aftab Hussain; Idress Afridi; YU Chong-xit; XIN Xiang-jun; YUAN Quan-xin; LIU Bo; Ashiq Hussain,; Abdul Latif; Abid Munir; Yousaf Khan

    2012-01-01

    We experimentally demonstrate and analyze a 10 Gbit/s full duplex wavelength division multiplexing passive optical network (WDM-PON) system.A non-return-to-zero differential phase shift keying (NRZ-DPSK) modulation technique is first utilized for downlink direction,and then the downlink signal is re-modulated for the uplink direction using intensity modulation technique of on-offkeying (OOK) with a data rate of 10 Gbit/s per channel.An effective colorless WDM-PON full duplex transmission system is achieved for the data rate of 10 Gbit/s per channel with a channel spacing of 60 GHz over the distance of 25 km with low power penalty.

  15. Use of Nonlinear Frequency Modulated Signals for the Enhancement of Subharmonic Response from Contrast Microbubbles

    Directory of Open Access Journals (Sweden)

    MUHAMMAD ARIF

    2017-01-01

    Full Text Available Ultrasound imaging with the subharmonic component from contrast microbubbles provide improved CTR (Contrast-to-Tissue Ratio, however it is susceptible to the low amplitude of the subharmonic component. In this simulation study, NLFM (Nonlinear Frequency Modulated signals are proposed in order to enhance the subharmonic response from microbubbles. NLFM signals having fractional bandwidths of 10, 20, and 40% with up and down sweeps were used as excitation. The performance of NLFM signals were compared with the reference tone-burst and LFM (Linear Frequency Modulated signals. The results show that the ultrasound contrast microbubbles can produce subharmonic response which is dependent on the applied signal pressure and bandwidth. It is observed that the subharmonic component of the scattered NLFM signal is 3.2dB higher than the LFM signal, whereas it is 9dB higher compared to the sinusoidal tone-burst signal. The results are also presented which show that the up and down sweeps NLFM signals performed better than the LFM signals at the same acoustic pressure and bandwidth.

  16. Optical signal monitoring in phase modulated optical fiber transmission systems

    Science.gov (United States)

    Zhao, Jian

    Optical performance monitoring (OPM) is one of the essential functions for future high speed optical networks. Among the parameters to be monitored, chromatic dispersion (CD) is especially important since it has a significant impact on overall system performance. In this thesis effective CD monitoring approaches for phase-shift keying (PSK) based optical transmission systems are investigated. A number of monitoring schemes based on radio frequency (RF) spectrum analysis and delay-tap sampling are proposed and their performance evaluated. A method for dispersion monitoring of differential phase-shift keying (DPSK) signals based on RF power detection is studied. The RF power spectrum is found to increase with the increase of CD and decrease with polarization mode dispersion (PMD). The spectral power density dependence on CD is studied theoretically and then verified through simulations and experiments. The monitoring sensitivity for nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) and return-to-zero differential phase-shift keying (RZ-DPSK) based systems can reach 80ps/nm/dB and 34ps/nm/dB respectively. The scheme enables the monitoring of differential group delay (DGD) and CD simultaneously. The monitoring sensitivity of CD and DGD can reach 56.7ps/nm/dB and 3.1ps/dB using a bandpass filter. The effects of optical signal-to-noise ratio (OSNR), DGD, fiber nonlinearity and chirp on the monitoring results are investigated. Two RF pilot tones are employed for CD monitoring of DPSK signals. Specially selected pilot tone frequencies enable good monitoring sensitivity with minimum influence on the received signals. The dynamic range exceeding 35dB and monitoring sensitivity up to 9.5ps/nm/dB are achieved. Asynchronous sampling technique is employed for CD monitoring. A signed CD monitoring method for 10Gb/s NRZ-DPSK and RZ-DPSK systems using asynchronous delay-tap sampling technique is studied. The demodulated signals suffer asymmetric waveform distortion if

  17. Exercise-induced endocannabinoid signaling is modulated by intensity.

    Science.gov (United States)

    Raichlen, David A; Foster, Adam D; Seillier, Alexandre; Giuffrida, Andrea; Gerdeman, Gregory L

    2013-04-01

    Endocannabinoids (eCB) are endogenous ligands for cannabinoid receptors that are densely expressed in brain networks responsible for reward. Recent work shows that exercise activates the eCB system in humans and other mammals, suggesting eCBs are partly responsible for the reported improvements in mood and affect following aerobic exercise in humans. However, exercise-induced psychological changes reported by runners are known to be dependent on exercise intensity, suggesting that any underlying molecular mechanism should also change with varying levels of exercise intensity. Here, we examine circulating levels of eCBs following aerobic exercise (treadmill running) in recreationally fit human runners at four different intensities. We show that eCB signaling is indeed intensity dependent, with significant changes in circulating eCBs observed following moderate intensities only (very high and very low intensity exercises do not significantly alter circulating eCB levels). Our results are consistent with intensity-dependent psychological state changes with exercise and therefore support the hypothesis that eCB activity is related to neurobiological effects of exercise. Thus, future studies examining the role of exercise-induced eCB signaling on neurobiology or physiology must take exercise intensity into account.

  18. Neurotransmitter receptor-mediated signaling pathways as modulators of carcinogenesis.

    Science.gov (United States)

    Schuller, Hildegard M

    2007-01-01

    The autonomic nervous system with its two antagonistic branches, the sympathicus and the parasympathicus, regulates the activities of all body functions that are not under voluntary control. While the autonomic regulation of organ functions has been extensively studied, little attention has been given to the potential role of neurohumoral transmission at the cellular level in the development of cancer. Studies conducted by our laboratory first showed that binding of the parasympathetic neurotransmitter, acetylcholine, as well as nicotine or its nitrosated cancer-causing derivative, NNK, to nicotinic acetylcholine receptors comprised of alpha7 subunits activated a mitogenic signal transduction pathway in normal and neoplastic pulmonary neuroendocrine cells. On the other hand, beta-adrenergic receptors (Beta-ARs), which transmit signals initiated by binding of the catecholamine neurotransmitters of the sympathicus, were identified by our laboratory as important regulators of cell proliferation in cell lines derived from human adenocarcinomas of the lungs, pancreas, and breast. The tobacco-specific carcinogen NNK bound with high affinity to Beta1- and Beta2-ARs, thus activating cAMP, protein kinase A, and the transcription factor CREB. Collectively, neurotransmitter receptors of the nicotinic and Beta-adrenergic families appear to regulate cellular functions essential for the development and survival of the most common human cancers.

  19. Information transfer through a signaling module with feedback: a perturbative approach

    CERN Document Server

    Aquino, Gerardo

    2015-01-01

    Signal transduction in biological cells is effected by signaling pathways that typically include multiple feedback loops. Here we analyze information transfer through a prototypical signaling module with biochemical feedback. The module switches stochastically between an inactive and active state; the input to the module governs the activation rate while the output (i.e., the product concentration) perturbs the inactivation rate. Using a novel perturbative approach, we compute the rate with which information about the input is gained from observation of the output. We obtain an explicit analytical result valid to first order in feedback strength and to second order in the strength of input. The total information gained during an extended time interval is found to depend on the feedback strength only through the total number of activation/inactivation events.

  20. Dependence of cross-relaxation on temperature and concentration from the {sup 1}D{sub 2} level of Pr{sup 3+} in YPO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Collins, John, E-mail: jcollins@wheatonma.edu [Department of Physics and Astronomy,Wheaton College, Norton, MA 02766 (United States); Geen, Megan [Department of Physics and Astronomy,Wheaton College, Norton, MA 02766 (United States); Bettinelli, M. [Dipartmento di Biotechnologie, Universita Delgi Studi di Verona, Verona (Italy); Di Bartolo, B. [Department of Physics, Boston College, Chestnut Hill, MA 02467 (United States)

    2012-10-15

    We report on the role of cross-relaxation in the decay of the {sup 1}D{sub 2} level of trivalent Pr in YPO{sub 4} in crystals with Pr concentrations of 0.1%, 1%, 2%, and 5%. We have found that the {sup 1}D{sub 2} level decay is purely radiative in the low-doped system. As the Pr concentration is increased, the {sup 1}D{sub 2} luminescence is quenched due to a cross-relaxation energy transfer between two Pr ions. The temporal behavior of the {sup 1}D{sub 2} luminescence following pulsed excitation has been monitored in each sample at temperatures between 30 K and 300 K, and all decay curves were fit to the Yokota-Tanimoto model. The decay times decrease as temperature increases, due to an increase in both the radiative rate and the energy transfer rate with temperature. There is little evidence of diffusion at any temperature, even in the more concentrated samples. We have also fit the decay curves using the LumiTrans computer simulation. A comparison of the fits to the decay curves of the two methods is presented. - Highlights: Black-Right-Pointing-Pointer We present data on the decay of the {sup 1}D{sub 2} level of Pr in YPO{sub 4} from 30-300 K. Black-Right-Pointing-Pointer We determine the {sup 1}D{sub 2} cross-relaxation rate throughout that temperature range. Black-Right-Pointing-Pointer Fits to the data indicate diffusion among the Pr ions is negligible. Black-Right-Pointing-Pointer Radiative efficiencies of the {sup 1}D{sub 2} level are determined.

  1. Modulation of connexin signaling by bacterial pathogens and their toxins.

    Science.gov (United States)

    Ceelen, Liesbeth; Haesebrouck, Freddy; Vanhaecke, Tamara; Rogiers, Vera; Vinken, Mathieu

    2011-09-01

    Inherent to their pivotal tasks in the maintenance of cellular homeostasis, gap junctions, connexin hemichannels, and pannexin hemichannels are frequently involved in the dysregulation of this critical balance. The present paper specifically focuses on their roles in bacterial infection and disease. In particular, the reported biological outcome of clinically important bacteria including Escherichia coli, Shigella flexneri, Yersinia enterocolitica, Helicobacter pylori, Bordetella pertussis, Aggregatibacter actinomycetemcomitans, Pseudomonas aeruginosa, Citrobacter rodentium, Clostridium species, Streptococcus pneumoniae, and Staphylococcus aureus and their toxic products on connexin- and pannexin-related signaling in host cells is reviewed. Particular attention is paid to the underlying molecular mechanisms of these effects as well as to the actual biological relevance of these findings.

  2. Covert communications using random noise signals: overall system simulation and modulation analysis

    Science.gov (United States)

    Chuang, Jack; Narayanan, Ram M.

    2005-06-01

    In military communications, there exist numerous potential threats to message security. Ultra-wideband (UWB) signals provide secure communications because they cannot, in general, be detected using conventional receivers and they can be made relatively immune from jamming. The security of an UWB signal can be further improved by mixing it with random noise. By using a random noise signal, the user can conceal the message signal within the noise waveform and thwart detection by hostile forces. This paper describes a novel spread spectrum technique that can be used for secure and covert communications. The technique is based on the use of heterodyne correlation techniques to inject coherence in a random noise signal. The modulated signal to be transmitted containing the coherent carrier is mixed with a sample of an ultrawideband random noise signal. The frequency range of the ultra-wideband noise signal is appropriately chosen so that the lower sideband of the mixing process falls over the same frequency range. Both the frequency-converted noise-like signal and the original random noise signal are simultaneously transmitted on orthogonally polarized channels through a dual-polarized transmitting antenna. The receiver consists of a similar dual-polarized antenna that simultaneously receives the two orthogonally polarized transmitted signals, amplifies each in a minimum phase limiting amplifier, and mixes these signals in a double sideband up-converter. The upper sideband of the mixing process recovers the modulated signal, which can then be demodulated. The advantage of this technique lies in the relative immunity of the random noise-like un-polarized transmit signal from detection and jamming. Since the transmit signal "appears" totally un-polarized and noise-like, linearly polarized receivers are unable to identify, decode, or otherwise extract useful information from the signal. The system is immune from interference caused by high power linearly polarized signal

  3. The concept of signal-to-noise ratio in the modulation domain and speech intelligibility.

    Science.gov (United States)

    Dubbelboer, Finn; Houtgast, Tammo

    2008-12-01

    A new concept is proposed that relates to intelligibility of speech in noise. The concept combines traditional estimations of signal-to-noise ratios (S/N) with elements from the modulation transfer function model, which results in the definition of the signal-to-noise ratio in the modulation domain: the (SN)(mod). It is argued that this (SN)(mod), quantifying the strength of speech modulations relative to a floor of spurious modulations arising from the speech-noise interaction, is the key factor in relation to speech intelligibility. It is shown that, by using a specific test signal, the strength of these spurious modulations can be measured, allowing an estimation of the (SN)(mod) for various conditions of additive noise, noise suppression, and amplitude compression. By relating these results to intelligibility data for these same conditions, the relevance of the (SN)(mod) as the key factor underlying speech intelligibility is clearly illustrated. For instance, it is shown that the commonly observed limited effect of noise suppression on speech intelligibility is correctly "predicted" by the (SN)(mod), whereas traditional measures such as the speech transmission index, considering only the changes in the speech modulations, fall short in this respect. It is argued that (SN)(mod) may provide a relevant tool in the design of successful noise-suppression systems.

  4. Signal Quality Enhancement of Directly- Modulated VCSELs Using a Micro-Ring Resonator Transfer Function

    DEFF Research Database (Denmark)

    An, Yi; Muller, M.; Estaran Tolosa, Jose Manuel

    2013-01-01

    A micro-ring resonator transfer function is used to enhance the quality of signals generated using directly modulated VCSELs. The scheme is demonstrated up to 25 Gbit/s with a 17.6-GHz VCSEL, with up to 10 dB sensitivity improvement.......A micro-ring resonator transfer function is used to enhance the quality of signals generated using directly modulated VCSELs. The scheme is demonstrated up to 25 Gbit/s with a 17.6-GHz VCSEL, with up to 10 dB sensitivity improvement....

  5. Modulation, resolution and signal processing in radar, sonar and related systems

    CERN Document Server

    Benjamin, R; Costrell, L

    1966-01-01

    Electronics and Instrumentation, Volume 35: Modulation, Resolution and Signal Processing in Radar, Sonar and Related Systems presents the practical limitations and potentialities of advanced modulation systems. This book discusses the concepts and techniques in the radar context, but they are equally essential to sonar and to a wide range of signaling and data-processing applications, including seismology, radio astronomy, and band-spread communications.Organized into 15 chapters, this volume begins with an overview of the principal developments sought in pulse radar. This text then provides a

  6. Improving the All-Optical Response of SOAs Using a Modulated Holding Signal

    DEFF Research Database (Denmark)

    Bischoff, Svend; Nielsen, Mads Lønstrup; Mørk, Jesper

    2004-01-01

    A method for increasing the all-optical modulation bandwidth of semiconductor optical amplifiers (SOAs) by use of a cross-gain-modulated (XGM) holding signal is suggested and analyzed. The bandwidth improvement is numerically demonstrated by studying wavelength conversion in an SOA-based Mach......-Zehnder interferometer (MZI) at 160 and 40 Gb/s. The new scheme is predicted to improve the extinction ratio and the minimum mark output power, as well as to reduce the amplitude jitter of the wavelength converted signal....

  7. Analytical analysis of modulated signal in apertureless scanning near-field optical microscopy.

    Science.gov (United States)

    Lo, Y L; Chuang, C H

    2007-11-26

    Eliminating background-scattering effects from the detected signal is crucial in improving the performance of super-high-resolution apertureless scanning near-field optical microscopy (A-SNOM). Using a simple mathematical model of the A-SNOM detected signal, this study explores the respective effects of the phase modulation depth, the wavelength and angle of the incident light, and the amplitude of the tip vibration on the signal contrast and signal intensity. In general, the results show that the background-noise decays as the order of the Bessel function increases and that higher-order harmonic frequencies yield an improved signal contrast. Additionally, it is found that incident light with a longer wavelength improves the signal contrast for a constant order of modulation frequency. The signal contrast can also be improved by reducing the incident angle of the incident light. Finally, it is demonstrated that sample stage scanning yields an improved imaging result. However, tip scanning provides a reasonable low-cost and faster solution in the smaller scan area. The analytical results presented in this study enable a better understanding of the complex detected signal in A-SNOM and provide insights into methods of improving the signal contrast of the A-SNOM measurement.

  8. A Multiplierless DC-Blocker for Single-Bit Sigma-Delta Modulated Signals

    OpenAIRE

    O'Shea Peter; Sadik Amin Z; Hussain Zahir M

    2007-01-01

    The DC content in single-bit domain is both undesirable and hard to remove. In this paper we propose a single-bit multiplierless DC-blocker structure. The input is assumed to be sigma-delta modulated bitstream. This DC-blocker is designed using a delta modulator topology with a sigma-delta modulator (SDM) embedded in its feedback path. Its performance is investigated in terms of the overall signal-to-noise ratio, the effectiveness of DC removal, and the stability. The proposed structure is e...

  9. A Multiplierless DC-Blocker for Single-Bit Sigma-Delta Modulated Signals

    Directory of Open Access Journals (Sweden)

    O'Shea Peter

    2007-01-01

    Full Text Available The DC content in single-bit domain is both undesirable and hard to remove. In this paper we propose a single-bit multiplierless DC-blocker structure. The input is assumed to be sigma-delta modulated bitstream. This DC-blocker is designed using a delta modulator topology with a sigma-delta modulator (SDM embedded in its feedback path. Its performance is investigated in terms of the overall signal-to-noise ratio, the effectiveness of DC removal, and the stability. The proposed structure is efficient for hardware realisation.

  10. Modulation Classification of Satellite Communication Signals Using Cumulants and Neural Networks

    Science.gov (United States)

    Smith, Aaron; Evans, Michael; Downey, Joseph

    2017-01-01

    National Aeronautics and Space Administration (NASA)'s future communication architecture is evaluating cognitive technologies and increased system intelligence. These technologies are expected to reduce the operational complexity of the network, increase science data return, and reduce interference to self and others. In order to increase situational awareness, signal classification algorithms could be applied to identify users and distinguish sources of interference. A significant amount of previous work has been done in the area of automatic signal classification for military and commercial applications. As a preliminary step, we seek to develop a system with the ability to discern signals typically encountered in satellite communication. Proposed is an automatic modulation classifier which utilizes higher order statistics (cumulants) and an estimate of the signal-to-noise ratio. These features are extracted from baseband symbols and then processed by a neural network for classification. The modulation types considered are phase-shift keying (PSK), amplitude and phase-shift keying (APSK),and quadrature amplitude modulation (QAM). Physical layer properties specific to the Digital Video Broadcasting - Satellite- Second Generation (DVB-S2) standard, such as pilots and variable ring ratios, are also considered. This paper will provide simulation results of a candidate modulation classifier, and performance will be evaluated over a range of signal-to-noise ratios, frequency offsets, and nonlinear amplifier distortions.

  11. Loss of MLK3 signaling impedes ulcer healing by modulating MAPK signaling in mouse intestinal mucosa.

    Science.gov (United States)

    Kovalenko, Pavlo L; Kunovska, Lyudmyla; Chen, Jian; Gallo, Kathleen A; Basson, Marc D

    2012-10-15

    Mixed-lineage kinase 3 (MLK3) activates multiple MAPK pathways and can initiate apoptosis, proliferation, migration, or differentiation in different cell types. However, whether MLK3 signaling regulates intestinal epithelial cell sheet migration in vivo is not known. We sought to investigate whether MLK3 signaling is important in intestinal mucosal healing and epithelial cell motility in vivo and in vitro. In vivo, we compared the healing of jejunal mucosal ulcers induced in MLK3 knockout (KO) mice with healing in wild-type (WT) mice. Ulcer healing was 20.8% less at day 3 (P MLK3 KO than WT mice. Within the intestinal mucosa of MLK3 KO mice, ERK and JNK signaling were reduced, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) level was increased, and p38 signaling was unchanged. Parallel in vitro studies using an MLK inhibitor assessed the role of MLK signaling in human Caco-2 intestinal epithelial migration across collagen substrates. The MLK inhibitor reduced closure of circular wounds in Caco-2 monolayers. MLK inhibition reduced ERK and JNK, but not p38, signaling in Caco-2 cells. Although PTEN is increased after MLK inhibition, it does not influence MLK-mediated cell migration. These findings indicate that disruption of MLK3 signaling impairs ulcer healing by suppressing ERK and JNK signaling in vitro and in mouse intestinal mucosa in vivo. These results reveal a novel role for MLK3 signaling in the regulation of intestinal epithelial migration in vivo and suggest that MLK3 may be an important target for the regulation of intestinal mucosal healing.

  12. Separation of overlapping linear frequency modulated (LFM) signals using the fractional fourier transform.

    Science.gov (United States)

    Cowell, David M J; Freear, Steven

    2010-10-01

    Linear frequency modulated (LFM) excitation combined with pulse compression provides an increase in SNR at the receiver. LFM signals are of longer duration than pulsed signals of the same bandwidth; consequently, in many practical situations, maintaining temporal separation between echoes is not possible. Where analysis is performed on individual LFM signals, a separation technique is required. Time windowing is unable to separate signals overlapping in time. Frequency domain filtering is unable to separate signals with overlapping spectra. This paper describes a method to separate time-overlapping LFM signals through the application of the fractional Fourier transform (FrFT), a transform operating in both time and frequency domains. A short introduction to the FrFT and its operation and calculation are presented. The proposed signal separation method is illustrated by application to a simulated ultrasound signal, created by the summation of multiple time-overlapping LFM signals and the component signals recovered with ±0.6% spectral error. The results of an experimental investigation are presented in which the proposed separation method is applied to time-overlapping LFM signals created by the transmission of a LFM signal through a stainless steel plate and water-filled pipe.

  13. Network modules help the identification of key transport routes, signaling pathways in cellular and other networks

    CERN Document Server

    Palotai, Robin

    2009-01-01

    Complex systems are successfully reduced to interacting elements via the network concept. Transport plays a key role in the survival of networks. For example the specialized signaling cascades of cellular networks filter noise and efficiently adapt the network structure to new stimuli. However, our general understanding of transport mechanisms and signaling pathways in complex systems is yet limited. Here we summarize the key network structures involved in transport, list the solutions available to overloaded systems for relaxing their load and outline a possible method for the computational determination of signaling pathways. We highlight that in addition to hubs, bridges and the network skeleton, the overlapping modular structure is also essential in network transport. Moreover, by locating network elements in the space of overlapping network modules and evaluating their distance in this "module space", it may be possible to approximate signaling pathways computationally, which, in turn could serve the ide...

  14. Modulation of the MAP kinase signaling cascade by Raf kinase inhibitory protein

    Institute of Scientific and Technical Information of China (English)

    Nicholas TRAKUL; Marsha R. ROSNER

    2005-01-01

    Proteins like Raf kinase inhibitory protein (RKIP) that serve as modulators of signaling pathways, either by promoting or inhibiting the formation of productive signaling complexes through protein-protein interactions, have been demonstrated to play an increasingly important role in a number of cell types and organisms. These proteins have been implicated in development as well as the progression of cancer. RKIP is a particularly interesting regulator, as it is a highly conserved, ubiquitously expressed protein that has been shown to play a role in growth and differentiation in a number of organisms and can regulate multiple signaling pathways. RKIP is also the first MAP kinase signaling modulator to be identified as playing a role in cancer metastasis, and identification of the mechanism by which it regulates Raf-1 activation provides new targets for therapeutic intervention.

  15. A multichannel neural signal detecting module: Its design and test in animal experiments

    Institute of Scientific and Technical Information of China (English)

    Wang Yufeng; Wang Zhigong; Lü Xiaoying; Gu Xiaosong; Li Wenyuan; Wang Huiling; Jiang Zhenlin; Lü Guangming; K. P. Koch

    2007-01-01

    A four-channel neural signal detecting module with an implantable 12-contact cuff electrode was designed for real-time neural signal recording on peripheral and central nerves. The mathematic coupling model between nerve and electronic system was analyzed. Electrode connection configurations were considered. The detecting circuit included an input coupling network, a pre-amplifier, and some filtering and notching stages. Shield guarding and the right-leg-driven circuit were developed for further elimination of common mode interference. By electrode switches, the module could cooperate with a nerve functional electrical stimulation circuit, building a neural channel bridge-connection system. It was tested by recording experiments on rat's sciatic and spine nerves. The signals in spontaneous and evoked conditions have been captured successfully. In addition, an implantable neural signal detecting CMOS IC has been introduced.

  16. Light and gravity signals synergize in modulating plant development

    Science.gov (United States)

    Vandenbrink, Joshua P.; Kiss, John Z.; Herranz, Raul; Medina, F. Javier

    2014-01-01

    Tropisms are growth-mediated plant movements that help plants to respond to changes in environmental stimuli. The availability of water and light, as well as the presence of a constant gravity vector, are all environmental stimuli that plants sense and respond to via directed growth movements (tropisms). The plant response to gravity (gravitropism) and the response to unidirectional light (phototropism) have long been shown to be interconnected growth phenomena. Here, we discuss the similarities in these two processes, as well as the known molecular mechanisms behind the tropistic responses. We also highlight research done in a microgravity environment in order to decouple two tropisms through experiments carried out in the absence of a significant unilateral gravity vector. In addition, alteration of gravity, especially the microgravity environment, and light irradiation produce important effects on meristematic cells, the undifferentiated, highly proliferating, totipotent cells which sustain plant development. Microgravity produces the disruption of meristematic competence, i.e., the decoupling of cell proliferation and cell growth, affecting the regulation of the cell cycle and ribosome biogenesis. Light irradiation, especially red light, mediated by phytochromes, has an activating effect on these processes. Phytohormones, particularly auxin, also are key mediators in these alterations. Upcoming experiments on the International Space Station will clarify some of the mechanisms and molecular players of the plant responses to these environmental signals involved in tropisms and the cell cycle. PMID:25389428

  17. Endocannabinoid signalling modulates susceptibility to traumatic stress exposure

    Science.gov (United States)

    Bluett, Rebecca J.; Báldi, Rita; Haymer, Andre; Gaulden, Andrew D.; Hartley, Nolan D.; Parrish, Walker P.; Baechle, Jordan; Marcus, David J.; Mardam-Bey, Ramzi; Shonesy, Brian C.; Uddin, Md. Jashim; Marnett, Lawrence J.; Mackie, Ken; Colbran, Roger J.; Winder, Danny G.; Patel, Sachin

    2017-01-01

    Stress is a ubiquitous risk factor for the exacerbation and development of affective disorders including major depression and posttraumatic stress disorder. Understanding the neurobiological mechanisms conferring resilience to the adverse consequences of stress could have broad implications for the treatment and prevention of mood and anxiety disorders. We utilize laboratory mice and their innate inter-individual differences in stress-susceptibility to demonstrate a critical role for the endogenous cannabinoid 2-arachidonoylglycerol (2-AG) in stress-resilience. Specifically, systemic 2-AG augmentation is associated with a stress-resilient phenotype and enhances resilience in previously susceptible mice, while systemic 2-AG depletion or CB1 receptor blockade increases susceptibility in previously resilient mice. Moreover, stress-resilience is associated with increased phasic 2-AG-mediated synaptic suppression at ventral hippocampal-amygdala glutamatergic synapses and amygdala-specific 2-AG depletion impairs successful adaptation to repeated stress. These data indicate amygdala 2-AG signalling mechanisms promote resilience to adverse effects of acute traumatic stress and facilitate adaptation to repeated stress exposure. PMID:28348378

  18. Light and gravity signals synergize in modulating plant development

    Directory of Open Access Journals (Sweden)

    Joshua P. Vandenbrink

    2014-10-01

    Full Text Available Tropisms are growth-mediated plant movements that help plants to respond to changes in environmental stimuli. The availability of water and light, as well as the presence of a constant gravity vector, are all environmental stimuli that plants sense and respond to via directed growth movements (tropisms. The plant response to gravity (gravitropism and the response to unidirectional light (phototropism have long been shown to be interconnected growth phenomena. Here, we discuss the similarities in these two processes, as well as the known molecular mechanisms behind the tropistic responses. We also highlight experiments done in a microgravity environment in order to decouple two tropisms through experiments carried out in the absence of a significant unilateral gravity vector. In addition, alteration of gravity, especially the microgravity environment, and light irradiation produce important effects on meristematic cells, the undifferentiated, highly proliferating, totipotent cells which sustain plant development. Microgravity produces the disruption of meristematic competence, i.e. the decoupling of cell proliferation and cell growth, affecting the regulation of cell cycle and ribosome biogenesis. Light irradiation, especially red light, mediated by phytochromes, has an activating effect on these processes. Phytohormones, particularly auxin, are key mediators in these alterations. Upcoming experiments on the International Space Station will clarify some of the unknown mechanisms and molecular players of the plant responses to these environmental signals involved in tropisms and the cell cycle.

  19. SodC modulates ras and PKB signaling in Dictyostelium.

    Science.gov (United States)

    Castillo, Boris; Kim, Seon-Hee; Sharief, Mujataba; Sun, Tong; Kim, Lou W

    2017-01-01

    We have previously reported that the basal RasG activity is aberrantly high in cells lacking Superoxide dismutase C (SodC). Here we report that other Ras proteins such as RasC and RasD activities are not affected in sodC(-) cells and mutagenesis studies showed that the presence of the Cys(118) in the Ras proteins is essential for the superoxide-mediated activation of Ras proteins in Dictyostelium. In addition to the loss of SodC, lack of extracellular magnesium ions increased the level of intracellular superoxide and active RasG proteins. Aberrantly active Ras proteins in sodC(-) cells persistently localized at the plasma membrane, but those in wild type cells under magnesium deficient medium exhibited intracellular vesicular localization. Interestingly, the aberrantly activated Ras proteins in wild type cells were largely insulated from their normal downstream events such as Phosphatidylinositol-3,4,5-P3 (PIP3) accumulation, Protein Kinase B (PKB) activation, and PKBs substrates phosphorylation. Intriguingly, however, aberrantly activated Ras proteins in sodC(-) cells were still engaged in signaling to their downstream targets, and thus excessive PKBs substrates phosphorylation persisted. In summary, we suggest that SodC and RasG proteins are essential part of a novel inhibitory mechanism that discourages oxidatively stressed cells from chemotaxis and thus inhibits the delivery of potentially damaged genome to the next generation.

  20. Modulation of signal transduction by tea catechins and related phytochemicals

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Masahito [Herbert Irving Comprehensive Cancer Center and Department of Medicine, Columbia University Medical Center, HHSC-1509, 701 West 168 Street, NY 10032-2704 (United States); Weinstein, I. Bernard [Herbert Irving Comprehensive Cancer Center and Department of Medicine, Columbia University Medical Center, HHSC-1509, 701 West 168 Street, NY 10032-2704 (United States)]. E-mail: ibw1@columbia.edu

    2005-12-11

    Epidemiologic studies in human populations and experimental studies in rodents provide evidence that green tea and its constituents can inhibit both the development and growth of tumors at a variety of tissue sites. In addition, EGCG, a major biologically active component of green tea, inhibits growth and induces apoptosis in a variety of cancer cell lines. The purpose of this paper is to review evidence that these effects are mediated, at least in part, through inhibition of the activity of specific receptor tyrosine kinases (RTKs) and related downstream pathways of signal transduction. We also review evidence indicating that the antitumor effects of the related polyphenolic phytochemicals resveratrol, genistein, curcumin, and capsaicin are exerted via similar mechanisms. Some of these agents (EGCG, genistein, and curcumin) appear to directly target specific RTKs, and all of these compounds cause inhibition of the activity of the transcription factors AP-1 and NF-{kappa}B, thus inhibiting cell proliferation and enhancing apoptosis. Critical areas of future investigation include: (1) identification of the direct molecular target(s) of EGCG and related polyphenolic compounds in cells; (2) the in vivo metabolism and bioavailability of these compounds; (3) the ancillary effects of these compounds on tumor-stromal interactions; (4) the development of synergistic combinations with other antitumor agents to enhance efficacy in cancer prevention and therapy, and also minimize potential toxicities.

  1. Randomised prior feedback modulates neural signals of outcome monitoring.

    Science.gov (United States)

    Mushtaq, Faisal; Wilkie, Richard M; Mon-Williams, Mark A; Schaefer, Alexandre

    2016-01-15

    Substantial evidence indicates that decision outcomes are typically evaluated relative to expectations learned from relatively long sequences of previous outcomes. This mechanism is thought to play a key role in general learning and adaptation processes but relatively little is known about the determinants of outcome evaluation when the capacity to learn from series of prior events is difficult or impossible. To investigate this issue, we examined how the feedback-related negativity (FRN) is modulated by information briefly presented before outcome evaluation. The FRN is a brain potential time-locked to the delivery of decision feedback and it is widely thought to be sensitive to prior expectations. We conducted a multi-trial gambling task in which outcomes at each trial were fully randomised to minimise the capacity to learn from long sequences of prior outcomes. Event-related potentials for outcomes (Win/Loss) in the current trial (Outcomet) were separated according to the type of outcomes that occurred in the preceding two trials (Outcomet-1 and Outcomet-2). We found that FRN voltage was more positive during the processing of win feedback when it was preceded by wins at Outcomet-1 compared to win feedback preceded by losses at Outcomet-1. However, no influence of preceding outcomes was found on FRN activity relative to the processing of loss feedback. We also found no effects of Outcomet-2 on FRN amplitude relative to current feedback. Additional analyses indicated that this effect was largest for trials in which participants selected a decision different to the gamble chosen in the previous trial. These findings are inconsistent with models that solely relate the FRN to prediction error computation. Instead, our results suggest that if stable predictions about future events are weak or non-existent, then outcome processing can be determined by affective systems. More specifically, our results indicate that the FRN is likely to reflect the activity of positive

  2. Optimization of Output Properties for Bias Signal-Modulated in a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    LI Tai-Quan; DONG Ping; YANG Hong-Quan; HAN Li-Bo

    2005-01-01

    Defining the quantity K as the signal-to-noise ratio (SNR) and the normalized intensity fluctuation C(0) of a single-mode laser for bias signal modulation driven by color noises with colored correlation, the whole output properties of the laser system is described by K. It is found that there is a maximum in the curves of K versus D, Q, and io. The optimization parameters are gained.

  3. Comparative analysis of modulation and demodulation methods of the control signals of rail line

    Directory of Open Access Journals (Sweden)

    K.V.Goncharov

    2012-12-01

    Full Text Available Introduction: One of the ways of increasing the noise stability rail circuit is the use more informative waveform of control signal. Use in rail circuit modulated signals gives several informative selective traits in relatively narrow spectrum. The study of features of various modulation and demodulation methods with considering operating conditions of rail circuits is urgent. Purpose: the search for more informative forms of rail line control signal, the search for improved methods of signal processing of control current. Methods: For carrying out researches the method of signals decomposition in Fourier series and the simulation with the method of statistical tests have been sed. Results: Spectrum of frequency shift signal is wider than the spectrum of amplitude shift and phase shift signals by an amount equal to twice the frequency deviation. The research of correlation coherent and incoherent reception methods of rail line control signal has been carried out. In this case, we used the following models of interferences: white Gaussian noise, random pulse sequence and sinusoidal interference. It has been found that the transition from amplitude to frequency shift keying reduces signal/noise ratio by 2...4 dB, depending from the signal level and the type of noise. Losing amplitude shift keying receiver compared with the phase shift keying receiver is 5...6 dB. Conclusions: The use of more advanced methods of modulation and demodulation improves noise stability of rail circuit. When using correlation methods reception phase shift keying provides the best noise stability, and amplitude – the worst.

  4. Loss of MLK3 signaling impedes ulcer healing by modulating MAPK signaling in mouse intestinal mucosa

    OpenAIRE

    Kovalenko, Pavlo L.; KUNOVSKA, LYUDMYLA; Chen, Jian; Kathleen A Gallo; Basson, Marc D.

    2012-01-01

    Mixed-lineage kinase 3 (MLK3) activates multiple MAPK pathways and can initiate apoptosis, proliferation, migration, or differentiation in different cell types. However, whether MLK3 signaling regulates intestinal epithelial cell sheet migration in vivo is not known. We sought to investigate whether MLK3 signaling is important in intestinal mucosal healing and epithelial cell motility in vivo and in vitro. In vivo, we compared the healing of jejunal mucosal ulcers induced in MLK3 knockout (KO...

  5. Micro-RNA Feedback Loops Modulating the Calcineurin/NFAT Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Shichina Kannambath

    2016-05-01

    Full Text Available Nuclear factor of activated T cells (NFAT is a family of transcription factors important for innate and adaptive immune responses. NFAT activation is tightly regulated through the calcineurin/NFAT signaling pathway. There is increasing evidence on non-coding RNAs such as miRNAs playing a crucial role in regulating transcription factors and signaling pathways. However, not much is known about microRNAs (miRNAs targeting the calcineurin/NFAT signaling pathway involved in immune response in human. In this study, a comprehensive pathway level analysis has been carried out to identify miRNAs regulating the calcineurin/NFAT signaling pathway. Firstly, by incorporating experimental data and computational predictions, 191 unique miRNAs were identified to be targeting the calcineurin/NFAT signaling pathway in humans. Secondly, combining miRNA expression data from activated T cells and computational predictions, 32 miRNAs were observed to be induced by NFAT transcription factors. Finally, 11 miRNAs were identified to be involved in a feedback loop to modulate the calcineurin/NFAT signaling pathway activity. This data demonstrate the potential role of miRNAs as regulators of the calcineurin/NFAT signaling pathway. The present study thus emphasizes the importance of pathway level analysis to identify miRNAs and understands their role in modulating signaling pathways and transcription factor activity.

  6. Fast identification of digital amplitude modulation level at low signal-to-noise ratio

    Institute of Scientific and Technical Information of China (English)

    WEI Xiao-wei; CAO Zhi-gang

    2006-01-01

    In order to rapidly and automatically identify the modulation level of digital amplitude modulated signals at low signal-to-noise ratio (SNR),a method of identifying the modulation levels of M-ary quadrature amplitude modulation (M-QAM)and M-ary amplitude shift keying (M-ASK) is proposed.In this method,wavelet transform with the optimal scale is used to identify the modulation levels of M-QAM and M-ASK signals.The performance of this method was investigated through simulations.Simulation results show that when the SNR is not lower than - 4 dB,the percentage of correct identification of M-QAM is higher than 93%,and when the SNR is not lower than -10 dB,the percentage of correct identification of M-ASK is higher than 90%,using only 100 observed symbols.It shows that this method can rapidly acquire good performance at a low SNR.

  7. Optically envelope detected QAM and QPSK RF modulated signals in hybrid wireless-fiber systems

    DEFF Research Database (Denmark)

    Tafur Monroy, Idelfonso; Prince, Kamau; Seoane, Jorge;

    2009-01-01

    from a 1.6 GHz carrier frequency to an IF at 500 MHz, requiring no high frequency local oscillator and mixer at the remote base station. This result proves the feasibility of optical envelope detection for complex modulation formats of RF signals for hybrid wireless-fiber transmission links....

  8. All-optical wavelength conversion and signal regeneration using an electroabsorption modulator

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    1999-01-01

    All-optical wavelength conversion in an InGaAsP quantum well electroabsorption modulator is studied at different bit-rates. We present theoretical results showing wavelength conversion efficiency in agreement with existing experimental results, and signal regeneration capability is demonstrated....

  9. Transmission and transparent wavelength conversion of an optically labeled signal using ASK/DPSK orthogonal modulation

    DEFF Research Database (Denmark)

    Chi, Nan; Zhang, Jianfeng; Holm-Nielsen, Pablo Villanueva

    2003-01-01

    We report an experimental investigation of transmission and transparent wavelength conversion properties of a two-level optically labeled signal using amplitude-shift-keying/differential-phase-shift-keying orthogonal modulation. Error-free transmission of a 10-Gb/s payload and 2.5-Gb/s label over...

  10. Optimal space communications techniques. [discussion of video signals and delta modulation

    Science.gov (United States)

    Schilling, D. L.

    1974-01-01

    The encoding of video signals using the Song Adaptive Delta Modulator (Song ADM) is discussed. The video signals are characterized as a sequence of pulses having arbitrary height and width. Although the ADM is suited to tracking signals having fast rise times, it was found that the DM algorithm (which permits an exponential rise for estimating an input step) results in a large overshoot and an underdamped response to the step. An overshoot suppression algorithm which significantly reduces the ringing while not affecting the rise time is presented along with formuli for the rise time and the settling time. Channel errors and their effect on the DM encoded bit stream were investigated.

  11. An extrasynaptic GABAergic signal modulates a pattern of forward movement in Caenorhabditis elegans

    Science.gov (United States)

    Shen, Yu; Wen, Quan; Liu, He; Zhong, Connie; Qin, Yuqi; Harris, Gareth; Kawano, Taizo; Wu, Min; Xu, Tianqi; Samuel, Aravinthan DT; Zhang, Yun

    2016-01-01

    As a common neurotransmitter in the nervous system, γ-aminobutyric acid (GABA) modulates locomotory patterns in both vertebrates and invertebrates. However, the signaling mechanisms underlying the behavioral effects of GABAergic modulation are not completely understood. Here, we demonstrate that a GABAergic signal in C. elegans modulates the amplitude of undulatory head bending through extrasynaptic neurotransmission and conserved metabotropic receptors. We show that the GABAergic RME head motor neurons generate undulatory activity patterns that correlate with head bending and the activity of RME causally links with head bending amplitude. The undulatory activity of RME is regulated by a pair of cholinergic head motor neurons SMD, which facilitate head bending, and inhibits SMD to limit head bending. The extrasynaptic neurotransmission between SMD and RME provides a gain control system to set head bending amplitude to a value correlated with optimal efficiency of forward movement. DOI: http://dx.doi.org/10.7554/eLife.14197.001 PMID:27138642

  12. Jumping the energetics queue: Modulation of pulsar signals by extraterrestrial civilizations

    CERN Document Server

    Chennamangalam, Jayanth; Lorimer, D R; Werthimer, Dan

    2013-01-01

    It has been speculated that technological civilizations evolve along an energy consumption scale first formulated by Kardashev, ranging from human-like civilizations that consume energy at a rate of $\\sim 10^{19}$ erg s$^{-1}$ to hypothetical highly advanced civilizations that can consume $\\sim 10^{44}$ erg s$^{-1}$. Since the transmission power of a beacon a civilization can build depends on the energy it possesses, to make it bright enough to be seen across the Galaxy would require high technological advancement. In this paper, we discuss the possibility of a civilization using naturally occurring radio transmitters - specifically, radio pulsars - to overcome the Kardashev limit of their developmental stage and transmit super-Kardashev power. This is achieved by the use of a modulator situated around a pulsar, that modulates the pulsar signal, encoding information onto its natural emission. We discuss a simple modulation model using pulse nulling and considerations for detecting such a signal. We find that ...

  13. Modulation of host cell signaling pathways as a therapeutic approach in periodontal disease

    Directory of Open Access Journals (Sweden)

    João Antonio Chaves de Souza

    2012-04-01

    Full Text Available Recently, new treatment approaches have been developed to target the host component of periodontal disease. This review aims at providing updated information on host-modulating therapies, focusing on treatment strategies for inhibiting signal transduction pathways involved in inflammation. Pharmacological inhibitors of MAPK, NFκB and JAK/STAT pathways are being developed to manage rheumatoid arthritis, periodontal disease and other inflammatory diseases. Through these agents, inflammatory mediators can be inhibited at cell signaling level, interfering on transcription factors activation and inflammatory gene expression. Although these drugs offer great potential to modulate host response, their main limitations are lack of specificity and developments of side effects. After overcoming these limitations, adjunctive host modulating drugs will provide new therapeutic strategies for periodontal treatment.

  14. Polyunsaturated fatty acids in the modulation of T-cell signalling.

    Science.gov (United States)

    Akhtar Khan, Naim

    2010-01-01

    n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activation are discussed. We particularly focus on how these fatty acids can modulate the production of diacylglycerol and the activation of protein kinase C, mitogen activated protein kinase, calcium signalling and translocation of transcriptional factors, implicated in the regulation of gene transcription in T-cells.

  15. An extrasynaptic GABAergic signal modulates a pattern of forward movement in Caenorhabditis elegans.

    Science.gov (United States)

    Shen, Yu; Wen, Quan; Liu, He; Zhong, Connie; Qin, Yuqi; Harris, Gareth; Kawano, Taizo; Wu, Min; Xu, Tianqi; Samuel, Aravinthan Dt; Zhang, Yun

    2016-05-03

    As a common neurotransmitter in the nervous system, γ-aminobutyric acid (GABA) modulates locomotory patterns in both vertebrates and invertebrates. However, the signaling mechanisms underlying the behavioral effects of GABAergic modulation are not completely understood. Here, we demonstrate that a GABAergic signal in C. elegans modulates the amplitude of undulatory head bending through extrasynaptic neurotransmission and conserved metabotropic receptors. We show that the GABAergic RME head motor neurons generate undulatory activity patterns that correlate with head bending and the activity of RME causally links with head bending amplitude. The undulatory activity of RME is regulated by a pair of cholinergic head motor neurons SMD, which facilitate head bending, and inhibits SMD to limit head bending. The extrasynaptic neurotransmission between SMD and RME provides a gain control system to set head bending amplitude to a value correlated with optimal efficiency of forward movement.

  16. Analysis of intra-pulse frequency-modulated, low probability of interception, radar signals

    Indian Academy of Sciences (India)

    A R SACHIN; SOORAJ K AMBAT; K V S HARI

    2017-07-01

    In this paper, we investigate the problem of analysis of low probability of interception (LPI) radar signals with intra-pulse frequency modulation (FM) under low signal-to-noise ratio conditions from the perspective of an airborne electronic warfare (EW) digital receiver. EW receivers are designed to intercept andanalyse threat radar signals of different classes, received over large dynamic range and operating independently over large geographical spread to advice host aircraft to undertake specified actions. For an EW receiver, primary challenges in interception and analysis of LPI radar signals are low received power, intra-pulse modulations,multi-octave frequency range, wide signal bandwidth, long pulse width, vast and multi-parametric search space, etc. In the present work, a method based on match filterbank localization and Taylor’s seriesapproximation for analysing the entire family of intra-pulse FM radar signals is proposed. The method involves progressive, joint time–frequency (TF) localization of the signal of interest (SOI), under piecewise linearity andcontinuity assumptions on instantaneous frequency, to effectively capture local TF signatures. Detection is by information-theoretic criterion based hypotheses testing, while estimation and classification are based on polynomial approximation. Fine signal analysis is followed by synthetic reconstruction of the received signal slope. Detection, estimation and classification performances for the prominent FM radar signal classes are quantified based on simulation study statistics. Stagewise implementation of analysis and FM slope reconstruction,in realistic radar threat scenarios, is demonstrated for the potential SOIs. Subject discussion is organized from the perspective of practical EW system design and presented within the realm of signal processing architecture of concurrent EW digital receivers.Keywords. Digital receiver (DRx); electronic warfare (

  17. CREB modulates calcium signaling in cAMP-induced bone marrow stromal cells (BMSCs).

    Science.gov (United States)

    Zhang, Linxia; Liu, Li; Thompson, Ryan; Chan, Christina

    2014-10-01

    Calcium signaling has a versatile role in many important cellular functions. Despite its importance, regulation of calcium signaling in bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) has not been explored extensively. Our previous study revealed that cyclic adenosine monophosphate (cAMP) enabled BMSCs to generate calcium signal upon stimulation by dopamine, KCl and glutamate. Concurrently, cAMP transiently activated the transcription factor cAMP response element binding protein (CREB) in BMSCs. Activity of CREB can be modulated by the calcium/calmodulin-dependent kinase signaling pathway, however, whether the calcium signaling observed in cAMP-induced BMSCs requires CREB has not been investigated. In an effort to uncover the role of CREB in the generation of calcium signaling in response to modulators such as dopamine and KCl, we knocked down CREB activity in BMSCs. Our study indicated that BMSCs, but not its close relative fibroblasts, are responsive to dopamine and KCl after cAMP treatment. Calcium signal elicited by dopamine depends, in part, on calcium influx whereas that elicited by KCl depends completely on calcium influx. Knock-down of CREB activity significantly reduced or abolished the cAMP-induced calcium response, and reintroducing a constitutively active CREB partially restored the calcium response.

  18. Quercetin and lithium chloride modulate Wnt signaling in pluripotent embryonal carcinoma NT2/D1 cells

    Directory of Open Access Journals (Sweden)

    Mojsin Marija

    2013-01-01

    Full Text Available Wnt signaling functions in numerous cellular activities such as cell fate determination, patterning, and migration in embryogenesis, apoptosis, etc. In this study, we used quercetin and lithium chloride to investigate modulations of the Wnt signaling pathway in human pluripotent embryonal carcinoma NT2/D1 cell line. First, we optimized conditions for NT2/D1 cell treatments with quercetin and lithium chloride and assessed their cytotoxic effects on the cells, cell viability and proliferation rate. Our results showed that induction of cell death by quercetin and LiCl is p53-dependent in NT2/D cells. We also examined the degree of Wnt signaling modulations by analyzing the expression of c-myc, a wellknown Wnt signaling target gene. Since the retinoic acid induction of NT2/D1 cells is good in an in vitro model system for human neural differentiation, studying Wnt signaling modulation in NT2/D1 would contribute to a better understanding of the mechanisms involved in neural stem cell maintenance and human neural development. [Projekat Ministarstva nauke Republike Srbije, br. 173051

  19. SPATA2 links CYLD to the TNF-α receptor signaling complex and modulates the receptor signaling outcomes.

    Science.gov (United States)

    Wagner, Sebastian A; Satpathy, Shankha; Beli, Petra; Choudhary, Chunaram

    2016-09-01

    TNF-α is a key regulator of innate immune and proinflammatory responses. However, the composition of the TNF-α receptor-associated signaling complexes (TNF-RSC) and the architecture of the downstream signaling networks are incompletely understood. We employed quantitative mass spectrometry to demonstrate that TNF-α stimulation induces widespread protein phosphorylation and that the scope of phosphorylation expands in a temporal manner. TNF-α stimulation also induces rapid ubiquitylation of components of the TNF-RSC Temporal analysis of the TNF-RSC composition identified SPATA2 as a novel component of the TNF-RSC The predicted PUB domain in the N-terminus of SPATA2 interacts with the USP domain of CYLD, whereas the C-terminus of SPATA2 interacts with HOIP SPATA2 is required for recruitment of CYLD to the TNF-RSC Downregulation of SPATA2 augments transcriptional activation of NF-κB and inhibits TNF-α-induced necroptosis, pointing to an important function of SPATA2 in modulating the outcomes of TNF-α signaling. Taken together, our study draws a detailed map of TNF-α signaling, identifies SPATA2 as a novel component of TNF-α signaling, and provides a rich resource for further functional investigations.

  20. The nature of relaxation processes revealed by the action signals of phase modulated light fields

    CERN Document Server

    Osipov, Vladimir Al; Hansen, Thorsten; Pullerits, Tõnu; Karki, Khadga Jung

    2016-01-01

    In the article we develop a theory of the action signals induced by the two-photon absorption of two phase modulated laser beams. In such experiments the phase of each laser beams is modulated at the frequencies $\\phi_1$ and $\\phi_2$, respectively, and the nonlinear signals are isolated at frequencies $m\\phi=m(\\phi_1-\\phi_2)$ ($m=0,1,2,\\dots$). We demonstrate that the ratio of the amplitudes of primary ($m=1$) and secondary ($m=2$) signals, $A_{\\phi}:A_{2\\phi}$, can be used as an indicator of the type of relaxation processes taking place in the material. The reference ratio value $4:1$ is achieved for the fast linear relaxation processes, and changes smoothly as the relaxation time increases. In case of bimolecular relaxation the ratio becomes a rapidly changing function of the excitation intensity. Our theoretical findings are supported by the experimental observations.

  1. Mitigation of nonlinear transmission effects for OFDM 16-QAM optical signal using adaptive modulation.

    Science.gov (United States)

    Skidin, Anton S; Sidelnikov, Oleg S; Fedoruk, Mikhail P; Turitsyn, Sergei K

    2016-12-26

    The impact of the fiber Kerr effect on error statistics in the nonlinear (high power) transmission of the OFDM 16-QAM signal over a 2000 km EDFA-based link is examined. We observed and quantified the difference in the error statistics for constellation points located at three power-defined rings. Theoretical analysis of a trade-off between redundancy and error rate reduction using probabilistic coding of three constellation power rings decreasing the symbol-error rate of OFDM 16-QAM signal is presented. Based on this analysis, we propose to mitigate the nonlinear impairments using the adaptive modulation technique applied to the OFDM 16-QAM signal. We demonstrate through numerical modelling the system performance improvement by the adaptive modulation for the large number of OFDM subcarriers (more than 100). We also show that a similar technique can be applied to single carrier transmission.

  2. Bridging the gap between modules in isolation and as part of networks: A systems framework for elucidating interaction and regulation of signalling modules.

    Science.gov (United States)

    Menon, Govind; Krishnan, J

    2016-07-21

    While signalling and biochemical modules have been the focus of numerous studies, they are typically studied in isolation, with no examination of the effects of the ambient network. In this paper we formulate and develop a systems framework, rooted in dynamical systems, to understand such effects, by studying the interaction of signalling modules. The modules we consider are (i) basic covalent modification, (ii) monostable switches, (iii) bistable switches, (iv) adaptive modules, and (v) oscillatory modules. We systematically examine the interaction of these modules by analyzing (a) sequential interaction without shared components, (b) sequential interaction with shared components, and (c) oblique interactions. Our studies reveal that the behaviour of a module in isolation may be substantially different from that in a network, and explicitly demonstrate how the behaviour of a given module, the characteristics of the ambient network, and the possibility of shared components can result in new effects. Our global approach illuminates different aspects of the structure and functioning of modules, revealing the importance of dynamical characteristics as well as biochemical features; this provides a methodological platform for investigating the complexity of natural modules shaped by evolution, elucidating the effects of ambient networks on a module in multiple cellular contexts, and highlighting the capabilities and constraints for engineering robust synthetic modules. Overall, such a systems framework provides a platform for bridging the gap between non-linear information processing modules, in isolation and as parts of networks, and a basis for understanding new aspects of natural and engineered cellular networks.

  3. Bridging the gap between modules in isolation and as part of networks: A systems framework for elucidating interaction and regulation of signalling modules

    Science.gov (United States)

    Menon, Govind; Krishnan, J.

    2016-07-01

    While signalling and biochemical modules have been the focus of numerous studies, they are typically studied in isolation, with no examination of the effects of the ambient network. In this paper we formulate and develop a systems framework, rooted in dynamical systems, to understand such effects, by studying the interaction of signalling modules. The modules we consider are (i) basic covalent modification, (ii) monostable switches, (iii) bistable switches, (iv) adaptive modules, and (v) oscillatory modules. We systematically examine the interaction of these modules by analyzing (a) sequential interaction without shared components, (b) sequential interaction with shared components, and (c) oblique interactions. Our studies reveal that the behaviour of a module in isolation may be substantially different from that in a network, and explicitly demonstrate how the behaviour of a given module, the characteristics of the ambient network, and the possibility of shared components can result in new effects. Our global approach illuminates different aspects of the structure and functioning of modules, revealing the importance of dynamical characteristics as well as biochemical features; this provides a methodological platform for investigating the complexity of natural modules shaped by evolution, elucidating the effects of ambient networks on a module in multiple cellular contexts, and highlighting the capabilities and constraints for engineering robust synthetic modules. Overall, such a systems framework provides a platform for bridging the gap between non-linear information processing modules, in isolation and as parts of networks, and a basis for understanding new aspects of natural and engineered cellular networks.

  4. High-frequency modulated signals of killer whales (Orcinus orca) in the North Pacific.

    Science.gov (United States)

    Simonis, Anne E; Baumann-Pickering, Simone; Oleson, Erin; Melcón, Mariana L; Gassmann, Martin; Wiggins, Sean M; Hildebrand, John A

    2012-04-01

    Killer whales in the North Pacific, similar to Atlantic populations, produce high-frequency modulated signals, based on acoustic recordings from ship-based hydrophone arrays and autonomous recorders at multiple locations. The median peak frequency of these signals ranged from 19.6-36.1 kHz and median duration ranged from 50-163 ms. Source levels were 185-193 dB peak-to-peak re: 1 μPa at 1 m. These uniform, repetitive, down-swept signals are similar to bat echolocation signals and possibly could have echolocation functionality. A large geographic range of occurrence suggests that different killer whale ecotypes may utilize these signals.

  5. Detection and processing of phase modulated optical signals at 40 Gbit/s and beyond

    DEFF Research Database (Denmark)

    Geng, Yan

    This thesis addresses demodulation in direct detection systems and signal processing of high speed phase modulated signals in future all-optical wavelength division multiplexing (WDM) communication systems where differential phase shift keying (DPSK) or differential quadrature phase shift keying...... labeling has been proposed as an efficient way to implement packet routing and forwarding functionalities in future IP-over-WDM networks. An in-band subcarrier multiplexing (SCM) labeled signal using 40 Gbit/s DSPK payload and 25 Mbit/s non return-to-zero(NRZ) SCM label, is successfully transmitted over 80...... noise, and consequently degrade the performance of systems making use of RZ-DPSK format. All-optical signal regeneration avoiding O-E-O conversion is desired to improve signal quality in ultra long-haul transmission systems. Proof-of-principle numerical simulation results are provided, that suggest...

  6. The Role of MAPK Modules and ABA during Abiotic Stress Signaling

    KAUST Repository

    Zélicourt, Axel de

    2016-05-01

    To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses in plants, triggering major changes in plant physiology. The ABA core signaling pathway largely relies on the activation of SnRK2 kinases to mediate several rapid responses, including gene regulation, stomatal closure, and plant growth modulation. Mitogen-activated protein kinases (MAPKs) have also been implicated in ABA signaling, but an entire ABA-activated MAPK module was uncovered only recently. In this review, we discuss the evidence for a role of MAPK modules in the context of different plant ABA signaling pathways. Abiotic stresses impact average yield in agriculture by more than 50% globally.Since ABA is a key regulator of abiotic stress responses, an understanding of its functioning at the molecular level is essential for plant breeding. Although the ABA core signaling pathway has been unraveled, several downstream events are still unclear.MAPKs are involved in most plant developmental stages and in response to stresses. Several members of the MAPK family were shown to be directly or indirectly activated by the ABA core signaling pathway.Recent evidence shows that the complete MAP3K17/18-MKK3-MPK1/2/7/14 module is under the control of ABA, whose members are under the transcriptional and post-translational control of the ABA core signaling pathway. © 2016 Elsevier Ltd.

  7. Frequency modulated weak signal detection based on stochastic resonance and genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    XING; Hongyan; LU; Chunxia; ZHANG; Qiang

    2016-01-01

    Stochastic resonance system is subject to the restriction of small frequency parameter in weak signal detection,in order to solve this problem,a frequency modulated weak signal detection method based on stochastic resonance and genetic algorithm is presented in this paper. The frequency limit of stochastic resonance is eliminated by introducing carrier signal,which is multiplied with the measured signal to be injected in the stochastic resonance system,meanwhile,using genetic algorithm to optimize the carrier signal frequency,which determine the generated difference-frequency signal in the lowfrequency range,so as to achieve the stochastic resonance weak signal detection. Results showthat the proposed method is feasible and effective,which can significantly improve the output SNR of stochastic resonance,in addition,the system has the better self-adaptability,according to the operation result and output phenomenon,the unknown frequency of the signal to be measured can be obtained,so as to realize the weak signal detection of arbitrary frequency.

  8. Jumping the energetics queue: Modulation of pulsar signals by extraterrestrial civilizations

    Science.gov (United States)

    Chennamangalam, Jayanth; Siemion, Andrew P. V.; Lorimer, D. R.; Werthimer, Dan

    2015-01-01

    It has been speculated that technological civilizations evolve along an energy consumption scale first formulated by Kardashev, ranging from human-like civilizations that consume energy at a rate of ∼1019 erg s-1 to hypothetical highly advanced civilizations that can consume ∼1044 erg s-1. Since the transmission power of a beacon a civilization can build depends on the energy it possesses, to make it bright enough to be seen across the Galaxy would require high technological advancement. In this paper, we discuss the possibility of a civilization using naturally-occurring radio transmitters - specifically, radio pulsars - to overcome the Kardashev limit of their developmental stage and transmit super-Kardashev power. This is achieved by the use of a modulator situated around a pulsar, that modulates the pulsar signal, encoding information onto its natural emission. We discuss a simple modulation model using pulse nulling and considerations for detecting such a signal. We find that a pulsar with a nulling modulator will exhibit an excess of thermal emission peaking in the ultraviolet during its null phases, revealing the existence of a modulator.

  9. Modulation of learning and memory by cytokines: signaling mechanisms and long term consequences.

    Science.gov (United States)

    Donzis, Elissa J; Tronson, Natalie C

    2014-11-01

    This review describes the role of cytokines and their downstream signaling cascades on the modulation of learning and memory. Immune proteins are required for many key neural processes and dysregulation of these functions by systemic inflammation can result in impairments of memory that persist long after the resolution of inflammation. Recent research has demonstrated that manipulations of individual cytokines can modulate learning, memory, and synaptic plasticity. The many conflicting findings, however, have prevented a clear understanding of the precise role of cytokines in memory. Given the complexity of inflammatory signaling, understanding its modulatory role requires a shift in focus from single cytokines to a network of cytokine interactions and elucidation of the cytokine-dependent intracellular signaling cascades. Finally, we propose that whereas signal transduction and transcription may mediate short-term modulation of memory, long-lasting cellular and molecular mechanisms such as epigenetic modifications and altered neurogenesis may be required for the long lasting impact of inflammation on memory and cognition. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Analysis of Filter-Bank-Based Methods for Fast Serial Acquisition of BOC-Modulated Signals

    Directory of Open Access Journals (Sweden)

    Elena Simona Lohan

    2007-09-01

    Full Text Available Binary-offset-carrier (BOC signals, selected for Galileo and modernized GPS systems, pose significant challenges for the code acquisition, due to the ambiguities (deep fades which are present in the envelope of the correlation function (CF. This is different from the BPSK-modulated CDMA signals, where the main correlation lobe spans over 2-chip interval, without any ambiguities or deep fades. To deal with the ambiguities due to BOC modulation, one solution is to use lower steps of scanning the code phases (i.e., lower than the traditional step of 0.5 chips used for BPSK-modulated CDMA signals. Lowering the time-bin steps entails an increase in the number of timing hypotheses, and, thus, in the acquisition times. An alternative solution is to transform the ambiguous CF into an “unambiguous” CF, via adequate filtering of the signal. A generalized class of frequency-based unambiguous acquisition methods is proposed here, namely the filter-bank-based (FBB approaches. The detailed theoretical analysis of FBB methods is given for serial-search single-dwell acquisition in single path static channels and a comparison is made with other ambiguous and unambiguous BOC acquisition methods existing in the literature.

  11. Analysis of Filter-Bank-Based Methods for Fast Serial Acquisition of BOC-Modulated Signals

    Directory of Open Access Journals (Sweden)

    Lohan ElenaSimona

    2007-01-01

    Full Text Available Binary-offset-carrier (BOC signals, selected for Galileo and modernized GPS systems, pose significant challenges for the code acquisition, due to the ambiguities (deep fades which are present in the envelope of the correlation function (CF. This is different from the BPSK-modulated CDMA signals, where the main correlation lobe spans over 2-chip interval, without any ambiguities or deep fades. To deal with the ambiguities due to BOC modulation, one solution is to use lower steps of scanning the code phases (i.e., lower than the traditional step of 0.5 chips used for BPSK-modulated CDMA signals. Lowering the time-bin steps entails an increase in the number of timing hypotheses, and, thus, in the acquisition times. An alternative solution is to transform the ambiguous CF into an "unambiguous" CF, via adequate filtering of the signal. A generalized class of frequency-based unambiguous acquisition methods is proposed here, namely the filter-bank-based (FBB approaches. The detailed theoretical analysis of FBB methods is given for serial-search single-dwell acquisition in single path static channels and a comparison is made with other ambiguous and unambiguous BOC acquisition methods existing in the literature.

  12. Development of MATLAB-Based Digital Signal Processing Teaching Module with Graphical User Interface Environment for Nigerian University

    OpenAIRE

    2013-01-01

    The development of a teaching aid module for digital Signal processing (DSP) in Nigeria Universities was undertaken to address the problem associated with non-availability instructional module. This paper annexes the potential of Peripheral Interface Controllers (PICs) with MATLAB resources to develop a PIC-based system with graphic user interface environment suitable for data acquisition and signal processing. The module accepts data from three different sources: real time acquisition, pre-r...

  13. Use of modulated excitation signals in medical ultrasound. Part III: High frame rate imaging

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    For pt.II, see ibid., vol.52, no.2, p.192-207 (2005). This paper, the last from a series of three papers on the application of coded excitation signals in medical ultrasound, investigates the possibility of increasing the frame rate in ultrasound imaging by using modulated excitation signals...... of 5, if a slight decrease in image quality can be accepted. The use of synthetic transmit aperture imaging is also considered, and it is here shown that Hadamard spatial encoding in transmit with FM emission signals can be used to increase the frame rate by 12 to 25 times with either a slight...... or no reduction in signal-to-noise ratio and image quality. By using these techniques, a complete ultrasound-phased array image can be created using only two emissions....

  14. Canonical Wnt signalling regulates epithelial patterning by modulating levels of laminins in zebrafish appendages.

    Science.gov (United States)

    Nagendran, Monica; Arora, Prateek; Gori, Payal; Mulay, Aditya; Ray, Shinjini; Jacob, Tressa; Sonawane, Mahendra

    2015-01-15

    The patterning and morphogenesis of body appendages - such as limbs and fins - is orchestrated by the activities of several developmental pathways. Wnt signalling is essential for the induction of limbs. However, it is unclear whether a canonical Wnt signalling gradient exists and regulates the patterning of epithelium in vertebrate appendages. Using an evolutionarily old appendage - the median fin in zebrafish - as a model, we show that the fin epithelium exhibits graded changes in cellular morphology along the proximo-distal axis. This epithelial pattern is strictly correlated with the gradient of canonical Wnt signalling activity. By combining genetic analyses with cellular imaging, we show that canonical Wnt signalling regulates epithelial cell morphology by modulating the levels of laminins, which are extracellular matrix components. We have unravelled a hitherto unknown mechanism involved in epithelial patterning, which is also conserved in the pectoral fins - evolutionarily recent appendages that are homologous to tetrapod limbs.

  15. Ring modulator small-signal response analysis based on pole-zero representation.

    Science.gov (United States)

    Karimelahi, Samira; Sheikholeslami, Ali

    2016-04-04

    We present a closed-form expression for the small-signal response of a depletion-mode ring modulator and verify it by measurement results. Both electrical and optical behavior of micro-ring modulator as well as the loss variation due to the index modulation is considered in the derivation. This expression suggests that a ring modulator is a third-order system with one real pole, one zero and a pair of complex-conjugate poles. The exact positions of the poles/zero are given and shown to be dependent upon parameters such as electrical bandwidth, coupling condition, optical loss, and sign/value of laser detunings. We show that the location of zero is different for positive and negative detuning, and therefore, the ring modulator frequency response is asymmetric. We use the gain-bandwidth product as a figure of merit and calculate it for various pole/zero locations. We show that gain-bandwidth for the over-coupled ring modulator is superior compared to other coupling conditions. Also, we show that the gain-bandwidth product can be increased to a limit by increasing the electrical bandwidth.

  16. OTUB1 modulates c-IAP1 stability to regulate signalling pathways.

    Science.gov (United States)

    Goncharov, Tatiana; Niessen, Kyle; de Almagro, Maria Cristina; Izrael-Tomasevic, Anita; Fedorova, Anna V; Varfolomeev, Eugene; Arnott, David; Deshayes, Kurt; Kirkpatrick, Donald S; Vucic, Domagoj

    2013-04-17

    The cellular inhibitor of apoptosis (c-IAP) proteins are E3 ubiquitin ligases that are critical regulators of tumour necrosis factor (TNF) receptor (TNFR)-mediated signalling. Through their E3 ligase activity c-IAP proteins promote ubiquitination of receptor-interaction protein 1 (RIP1), NF-κB-inducing kinase (NIK) and themselves, and regulate the assembly of TNFR signalling complexes. Consequently, in the absence of c-IAP proteins, TNFR-mediated activation of NF-κB and MAPK pathways and the induction of gene expression are severely reduced. Here, we describe the identification of OTUB1 as a c-IAP-associated deubiquitinating enzyme that regulates c-IAP1 stability. OTUB1 disassembles K48-linked polyubiquitin chains from c-IAP1 in vitro and in vivo within the TWEAK receptor-signalling complex. Downregulation of OTUB1 promotes TWEAK- and IAP antagonist-stimulated caspase activation and cell death, and enhances c-IAP1 degradation. Furthermore, knockdown of OTUB1 reduces TWEAK-induced activation of canonical NF-κB and MAPK signalling pathways and modulates TWEAK-induced gene expression. Finally, suppression of OTUB1 expression in zebrafish destabilizes c-IAP (Birc2) protein levels and disrupts fish vasculature. These results suggest that OTUB1 regulates NF-κB and MAPK signalling pathways and TNF-dependent cell death by modulating c-IAP1 stability.

  17. Neural network surface acoustic wave RF signal processor for digital modulation recognition.

    Science.gov (United States)

    Kavalov, Dimitar; Kalinin, Victor

    2002-09-01

    An architecture of a surface acoustic wave (SAW) processor based on an artificial neural network is proposed for an automatic recognition of different types of digital passband modulation. Three feed-forward networks are trained to recognize filtered and unfiltered binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals, as well as unfiltered BPSK, QPSK, and 16 quadrature amplitude (16QAM) signals. Performance of the processor in the presence of additive white Gaussian noise (AWGN) is simulated. The influence of second-order effects in SAW devices, phase, and amplitude errors on the performance of the processor also is studied.

  18. An investigation of the influence of residual amplitude modulation in phase electro-optic modulator on the signal of fiber-optic gyroscope

    Science.gov (United States)

    Pogorelaya, D. A.; Smolovik, M. A.; Strigalev, V. E.; Aleynik, A. S.; Deyneka, I. G.

    2016-08-01

    The investigation is devoted to residual amplitude modulation (RAM) of phase electro-optic modulator, which guides are made in LiNbO3 crystal by Ti diffusion technology. An analysis is presented that shows influence of RAM on the signal of fiber-optic gyroscope. The RAM compensation method is offered.

  19. Parameters estimation of sinusoidal frequency modulation signal with application in synthetic aperture radar imaging

    Science.gov (United States)

    Wang, Yong; Wang, Zhaofa; Zhao, Bin; Xu, Liang

    2016-04-01

    A method for estimating the parameters of the sinusoidal frequency modulation (SFM) signal is presented in this paper. Based on the modified discrete sinusoid frequency modulation transform (DSFMT), the SFM signal can be transformed into the DSFMT domain where it is energy-concentrated and then the parameters can be estimated by the global maximum. To search for the location of the global maximum with less computational load, particle swarm optimization is used in this paper. Then the algorithm is used in the synthetic aperture radar imaging with high frequency vibration of the platform, and the focus performance can be improved significantly. Simulation results demonstrate the effectiveness of the method proposed in this paper.

  20. Direct Modulation of Heterotrimeric G Protein-coupled Signaling by a Receptor Kinase Complex.

    Science.gov (United States)

    Tunc-Ozdemir, Meral; Urano, Daisuke; Jaiswal, Dinesh Kumar; Clouse, Steven D; Jones, Alan M

    2016-07-01

    Plants and some protists have heterotrimeric G protein complexes that activate spontaneously without canonical G protein-coupled receptors (GPCRs). In Arabidopsis, the sole 7-transmembrane regulator of G protein signaling 1 (AtRGS1) modulates the G protein complex by keeping it in the resting state (GDP-bound). However, it remains unknown how a myriad of biological responses is achieved with a single G protein modulator. We propose that in complete contrast to G protein activation in animals, plant leucine-rich repeat receptor-like kinases (LRR RLKs), not GPCRs, provide this discrimination through phosphorylation of AtRGS1 in a ligand-dependent manner. G protein signaling is directly activated by the pathogen-associated molecular pattern flagellin peptide 22 through its LRR RLK, FLS2, and co-receptor BAK1.

  1. Neural interactions in unilateral colliculus and between bilateral colliculi modulate auditory signal processing

    Science.gov (United States)

    Mei, Hui-Xian; Cheng, Liang; Chen, Qi-Cai

    2013-01-01

    In the auditory pathway, the inferior colliculus (IC) is a major center for temporal and spectral integration of auditory information. There are widespread neural interactions in unilateral (one) IC and between bilateral (two) ICs that could modulate auditory signal processing such as the amplitude and frequency selectivity of IC neurons. These neural interactions are either inhibitory or excitatory, and are mostly mediated by γ-aminobutyric acid (GABA) and glutamate, respectively. However, the majority of interactions are inhibitory while excitatory interactions are in the minority. Such unbalanced properties between excitatory and inhibitory projections have an important role in the formation of unilateral auditory dominance and sound location, and the neural interaction in one IC and between two ICs provide an adjustable and plastic modulation pattern for auditory signal processing. PMID:23626523

  2. Neural interactions in unilateral colliculus and between bilateral colliculi modulate auditory signal processing.

    Science.gov (United States)

    Mei, Hui-Xian; Cheng, Liang; Chen, Qi-Cai

    2013-01-01

    In the auditory pathway, the inferior colliculus (IC) is a major center for temporal and spectral integration of auditory information. There are widespread neural interactions in unilateral (one) IC and between bilateral (two) ICs that could modulate auditory signal processing such as the amplitude and frequency selectivity of IC neurons. These neural interactions are either inhibitory or excitatory, and are mostly mediated by γ-aminobutyric acid (GABA) and glutamate, respectively. However, the majority of interactions are inhibitory while excitatory interactions are in the minority. Such unbalanced properties between excitatory and inhibitory projections have an important role in the formation of unilateral auditory dominance and sound location, and the neural interaction in one IC and between two ICs provide an adjustable and plastic modulation pattern for auditory signal processing.

  3. 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.

  4. Optogenetic Modulation of Intracellular Signalling and Transcription: Focus on Neuronal Plasticity.

    Science.gov (United States)

    Eleftheriou, Cyril; Cesca, Fabrizia; Maragliano, Luca; Benfenati, Fabio; Maya-Vetencourt, Jose Fernando

    2017-01-01

    Several fields in neuroscience have been revolutionized by the advent of optogenetics, a technique that offers the possibility to modulate neuronal physiology in response to light stimulation. This innovative and far-reaching tool provided unprecedented spatial and temporal resolution to explore the activity of neural circuits underlying cognition and behaviour. With an exponential growth in the discovery and synthesis of new photosensitive actuators capable of modulating neuronal networks function, other fields in biology are experiencing a similar re-evolution. Here, we review the various optogenetic toolboxes developed to influence cellular physiology as well as the diverse ways in which these can be engineered to precisely modulate intracellular signalling and transcription. We also explore the processes required to successfully express and stimulate these photo-actuators in vivo before discussing how such tools can enlighten our understanding of neuronal plasticity at the systems level.

  5. Modulating Wnt Signaling Pathway to Enhance Allograft Integration in Orthopedic Trauma Treatment

    Science.gov (United States)

    2014-04-01

    TITLE: Modulating Wnt Signaling Pathway to Enhance Allograft Integration in Orthopedic Trauma Treatment PRINCIPAL INVESTIGATOR: Amarjit S...Integration in Orthopedic Trauma Treatment 5b. GRANT NUMBER W81XWH-10-1-1054 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Amarjit S. Virdi, PhD...practical means of enhancing repair of large bone defects in orthopedic trauma and can be translated into clinical practice in the near future. Figures

  6. Modulating Wnt Signaling Pathway to Enhance Allograft Integration in Orthopaedic Trauma Treatment

    Science.gov (United States)

    2012-10-01

    Sena, K.; McNulty, M. A.; Ke, H. Z.; Liu, M.; Sumner, D. R. Sclerostin antibody increases peri-implant bone formation in a rat ovariectomy model...modulating Wnt signaling pathway in the bone tissue repair by using monoclonal antibodies against sclerostin (Sost) and DKK-1 (donated by Amgen Inc...the data is encouraging as it reveals that the use of anti-Sost or anti-Dkk-1 antibodies enhances new bone formation around the allograft. The

  7. Linearized Optically Phase-Modulated Fiber Optic Links for Microwave Signal Transport

    Science.gov (United States)

    2009-03-03

    a number of external modulation techniques. For particularly long links, a single or small number of Erbium-Doped Fiber Amplifiers ( EDFA ) could...amplifier (Erbium-Doped Fiber Amplifier, or EDFA ) is present, its noise contribution is caused by beating between the signal and the...the absence of an EDFA , received optical powers that generate photocurrents below approximately 1 mA cause the system noise to be dominated by the

  8. Modulator and VCSEL-MSM smart pixels for parallel pipeline networking and signal processing

    Science.gov (United States)

    Chen, C.-H.; Hoanca, Bogdan; Kuznia, C. B.; Pansatiankul, Dhawat E.; Zhang, Liping; Sawchuk, Alexander A.

    1999-07-01

    TRANslucent Smart Pixel Array (TRANSPAR) systems perform high performance parallel pipeline networking and signal processing based on optical propagation of 3D data packets. The TRANSPAR smart pixel devices use either self-electro- optic effect GaAs multiple quantum well modulators or CMOS- VCSEL-MSM (CMOS-Vertical Cavity Surface Emitting Laser- Metal-Semiconductor-Metal) technology. The data packets transfer among high throughput photonic network nodes using multiple access/collision detection or token-ring protocols.

  9. The Drosophila homologue of the amyloid precursor protein is a conserved modulator of Wnt PCP signaling.

    Directory of Open Access Journals (Sweden)

    Alessia Soldano

    Full Text Available Wnt Planar Cell Polarity (PCP signaling is a universal regulator of polarity in epithelial cells, but it regulates axon outgrowth in neurons, suggesting the existence of axonal modulators of Wnt-PCP activity. The Amyloid precursor proteins (APPs are intensely investigated because of their link to Alzheimer's disease (AD. APP's in vivo function in the brain and the mechanisms underlying it remain unclear and controversial. Drosophila possesses a single APP homologue called APP Like, or APPL. APPL is expressed in all neurons throughout development, but has no established function in neuronal development. We therefore investigated the role of Drosophila APPL during brain development. We find that APPL is involved in the development of the Mushroom Body αβ neurons and, in particular, is required cell-autonomously for the β-axons and non-cell autonomously for the α-axons growth. Moreover, we find that APPL is a modulator of the Wnt-PCP pathway required for axonal outgrowth, but not cell polarity. Molecularly, both human APP and fly APPL form complexes with PCP receptors, thus suggesting that APPs are part of the membrane protein complex upstream of PCP signaling. Moreover, we show that APPL regulates PCP pathway activation by modulating the phosphorylation of the Wnt adaptor protein Dishevelled (Dsh by Abelson kinase (Abl. Taken together our data suggest that APPL is the first example of a modulator of the Wnt-PCP pathway specifically required for axon outgrowth.

  10. Microbiota-Modulated Metabolites Shape the Intestinal Microenvironment by Regulating NLRP6 Inflammasome Signaling.

    Science.gov (United States)

    Levy, Maayan; Thaiss, Christoph A; Zeevi, David; Dohnalová, Lenka; Zilberman-Schapira, Gili; Mahdi, Jemal Ali; David, Eyal; Savidor, Alon; Korem, Tal; Herzig, Yonatan; Pevsner-Fischer, Meirav; Shapiro, Hagit; Christ, Anette; Harmelin, Alon; Halpern, Zamir; Latz, Eicke; Flavell, Richard A; Amit, Ido; Segal, Eran; Elinav, Eran

    2015-12-01

    Host-microbiome co-evolution drives homeostasis and disease susceptibility, yet regulatory principles governing the integrated intestinal host-commensal microenvironment remain obscure. While inflammasome signaling participates in these interactions, its activators and microbiome-modulating mechanisms are unknown. Here, we demonstrate that the microbiota-associated metabolites taurine, histamine, and spermine shape the host-microbiome interface by co-modulating NLRP6 inflammasome signaling, epithelial IL-18 secretion, and downstream anti-microbial peptide (AMP) profiles. Distortion of this balanced AMP landscape by inflammasome deficiency drives dysbiosis development. Upon fecal transfer, colitis-inducing microbiota hijacks this microenvironment-orchestrating machinery through metabolite-mediated inflammasome suppression, leading to distorted AMP balance favoring its preferential colonization. Restoration of the metabolite-inflammasome-AMP axis reinstates a normal microbiota and ameliorates colitis. Together, we identify microbial modulators of the NLRP6 inflammasome and highlight mechanisms by which microbiome-host interactions cooperatively drive microbial community stability through metabolite-mediated innate immune modulation. Therefore, targeted "postbiotic" metabolomic intervention may restore a normal microenvironment as treatment or prevention of dysbiosis-driven diseases.

  11. The Drosophila homologue of the amyloid precursor protein is a conserved modulator of Wnt PCP signaling.

    Science.gov (United States)

    Soldano, Alessia; Okray, Zeynep; Janovska, Pavlina; Tmejová, Kateřina; Reynaud, Elodie; Claeys, Annelies; Yan, Jiekun; Atak, Zeynep Kalender; De Strooper, Bart; Dura, Jean-Maurice; Bryja, Vítězslav; Hassan, Bassem A

    2013-01-01

    Wnt Planar Cell Polarity (PCP) signaling is a universal regulator of polarity in epithelial cells, but it regulates axon outgrowth in neurons, suggesting the existence of axonal modulators of Wnt-PCP activity. The Amyloid precursor proteins (APPs) are intensely investigated because of their link to Alzheimer's disease (AD). APP's in vivo function in the brain and the mechanisms underlying it remain unclear and controversial. Drosophila possesses a single APP homologue called APP Like, or APPL. APPL is expressed in all neurons throughout development, but has no established function in neuronal development. We therefore investigated the role of Drosophila APPL during brain development. We find that APPL is involved in the development of the Mushroom Body αβ neurons and, in particular, is required cell-autonomously for the β-axons and non-cell autonomously for the α-axons growth. Moreover, we find that APPL is a modulator of the Wnt-PCP pathway required for axonal outgrowth, but not cell polarity. Molecularly, both human APP and fly APPL form complexes with PCP receptors, thus suggesting that APPs are part of the membrane protein complex upstream of PCP signaling. Moreover, we show that APPL regulates PCP pathway activation by modulating the phosphorylation of the Wnt adaptor protein Dishevelled (Dsh) by Abelson kinase (Abl). Taken together our data suggest that APPL is the first example of a modulator of the Wnt-PCP pathway specifically required for axon outgrowth.

  12. Allatostatin A Signalling in Drosophila Regulates Feeding and Sleep and Is Modulated by PDF.

    Science.gov (United States)

    Chen, Jiangtian; Reiher, Wencke; Hermann-Luibl, Christiane; Sellami, Azza; Cognigni, Paola; Kondo, Shu; Helfrich-Förster, Charlotte; Veenstra, Jan A; Wegener, Christian

    2016-09-01

    Feeding and sleep are fundamental behaviours with significant interconnections and cross-modulations. The circadian system and peptidergic signals are important components of this modulation, but still little is known about the mechanisms and networks by which they interact to regulate feeding and sleep. We show that specific thermogenetic activation of peptidergic Allatostatin A (AstA)-expressing PLP neurons and enteroendocrine cells reduces feeding and promotes sleep in the fruit fly Drosophila. The effects of AstA cell activation are mediated by AstA peptides with receptors homolog to galanin receptors subserving similar and apparently conserved functions in vertebrates. We further identify the PLP neurons as a downstream target of the neuropeptide pigment-dispersing factor (PDF), an output factor of the circadian clock. PLP neurons are contacted by PDF-expressing clock neurons, and express a functional PDF receptor demonstrated by cAMP imaging. Silencing of AstA signalling and continuous input to AstA cells by tethered PDF changes the sleep/activity ratio in opposite directions but does not affect rhythmicity. Taken together, our results suggest that pleiotropic AstA signalling by a distinct neuronal and enteroendocrine AstA cell subset adapts the fly to a digestive energy-saving state which can be modulated by PDF.

  13. Allatostatin A Signalling in Drosophila Regulates Feeding and Sleep and Is Modulated by PDF.

    Directory of Open Access Journals (Sweden)

    Jiangtian Chen

    2016-09-01

    Full Text Available Feeding and sleep are fundamental behaviours with significant interconnections and cross-modulations. The circadian system and peptidergic signals are important components of this modulation, but still little is known about the mechanisms and networks by which they interact to regulate feeding and sleep. We show that specific thermogenetic activation of peptidergic Allatostatin A (AstA-expressing PLP neurons and enteroendocrine cells reduces feeding and promotes sleep in the fruit fly Drosophila. The effects of AstA cell activation are mediated by AstA peptides with receptors homolog to galanin receptors subserving similar and apparently conserved functions in vertebrates. We further identify the PLP neurons as a downstream target of the neuropeptide pigment-dispersing factor (PDF, an output factor of the circadian clock. PLP neurons are contacted by PDF-expressing clock neurons, and express a functional PDF receptor demonstrated by cAMP imaging. Silencing of AstA signalling and continuous input to AstA cells by tethered PDF changes the sleep/activity ratio in opposite directions but does not affect rhythmicity. Taken together, our results suggest that pleiotropic AstA signalling by a distinct neuronal and enteroendocrine AstA cell subset adapts the fly to a digestive energy-saving state which can be modulated by PDF.

  14. Belief about nicotine selectively modulates value and reward prediction error signals in smokers

    Science.gov (United States)

    Gu, Xiaosi; Lohrenz, Terry; Salas, Ramiro; Baldwin, Philip R.; Soltani, Alireza; Kirk, Ulrich; Cinciripini, Paul M.; Montague, P. Read

    2015-01-01

    Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers’ prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers’ beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of “no nicotine in cigarette” (compared with “nicotine in cigarette”) strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers’ choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems. PMID:25605923

  15. Signal-to-Noise Measurements on Irradiated CMS Tracker Detector Modules in an Electron Testbeam

    CERN Document Server

    Bleyl, Mark; Steinbruck, G; Stoye, M; Dragicevica, M; Hrubec, Josef; Krammer, M; Frey, M; Hartmann, F; Weiler, T; Hegner, B

    2006-01-01

    The CMS experiment at the Large Hadron Collider at CERN is in the last phase of its construction. The harsh radiation environment at LHC will put strong demands in radiation hardness to the innermost parts of the detector. To assess the performance of irradiated microstrip detector modules, a testbeam was conducted at the Testbeam 22 facility of the DESY research center. The primary objective was the signal-to-noise measurement of irradiated CMS Tracker modules to ensure their functionality up to 10 years of LHC operation. The paper briefly summarises the basic setup at the facility and the hardware and software used to collect and analyse the data. Some interesting subsidiary results are shown, which confirm the expected behaviour of the detector with respect to the signal-to-noise performance over the active detector area and for different electron energies. The main focus of the paper are the results of the signal-to-noise measurements for CMS Tracker Modules which were exposed to different radiation doses...

  16. Belief about nicotine selectively modulates value and reward prediction error signals in smokers.

    Science.gov (United States)

    Gu, Xiaosi; Lohrenz, Terry; Salas, Ramiro; Baldwin, Philip R; Soltani, Alireza; Kirk, Ulrich; Cinciripini, Paul M; Montague, P Read

    2015-02-24

    Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers' prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers' beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of "no nicotine in cigarette" (compared with "nicotine in cigarette") strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers' choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems.

  17. Reduction of pattern effects in SOA-based all-optical switches by using cross-gain modulated holding signal

    DEFF Research Database (Denmark)

    Bischoff, Svend; Mørk, Jesper

    2002-01-01

    and data signal power. Here, we demonstrate that the modulation bandwidth (amplitude jitter) is significantly improved (reduced) by replacing the CW holding beam with a signal, which is low-pass filtered and inverted with respect to the data signal. Such a holding beam can be generated by XGM WC in an SOA...

  18. Applications of all optical signal processing for advanced optical modulation formats

    Science.gov (United States)

    Nuccio, Scott R.

    Increased data traffic demands, along with a continual push to minimize cost per bit, have recently motivated a paradigm shift away from traditional on-off keying (OOK) fiber transmission links towards systems utilizing more advanced modulation formats. In particular, modulation formats that utilize the phase of the optical signal, including differential phase shift keying (DPSK) and differential quadrature phase shift keying (DQPSK) along with polarization multiplexing (Pol-MUX), have recently emerged as the most popular means for transmitting information over long-haul and ultra-long haul fiber transmission systems. DPSK is motivated by an increase in receiver sensitivity compared to traditional OOK. DQPSK is motivated by a doubling of the spectral efficiency, along with increased tolerance to dispersion and nonlinear distortions. Coherent communications has also emerged as a primary means of transmitting and receiving optical data due to its support of formats that utilize both phase and amplitude to further increase the spectral efficiency (bits/sec/Hz) of the optical channel, including quadrature amplitude modulation (QAM). Polarization multiplexing of channels is a straight forward method to allow two channels to share the same wavelength by propagating on orthogonal polarization axis and is easily supported in coherent systems where the polarization tracking can be performed in the digital domain. Furthermore, the forthcoming IEEE 100 Gbit/s Ethernet Standard, 802.3ba, provides greater bandwidth, higher data rates, and supports a mixture of modulation formats. In particular, Pol-MUX (D)QPSK has grown in interest as the high spectral efficiency allows for 100 Gbit/s transmission while still occupying the current 50 GHz/channel allocation of current 10 Gbit/s OOK fiber systems. In this manner, 100 Gbit/s transfer speeds using current fiber links, amplifiers, and filters may be possible. In addition to advanced modulation formats, it is expected that optical

  19. Protein conservation and variation suggest mechanisms of cell type-specific modulation of signaling pathways.

    Directory of Open Access Journals (Sweden)

    Martin H Schaefer

    2014-06-01

    Full Text Available Many proteins and signaling pathways are present in most cell types and tissues and yet perform specialized functions. To elucidate mechanisms by which these ubiquitous pathways are modulated, we overlaid information about cross-cell line protein abundance and variability, and evolutionary conservation onto functional pathway components and topological layers in the pathway hierarchy. We found that the input (receptors and the output (transcription factors layers evolve more rapidly than proteins in the intermediary transmission layer. In contrast, protein expression variability decreases from the input to the output layer. We observed that the differences in protein variability between the input and transmission layer can be attributed to both the network position and the tendency of variable proteins to physically interact with constitutively expressed proteins. Differences in protein expression variability and conservation are also accompanied by the tendency of conserved and constitutively expressed proteins to acquire somatic mutations, while germline mutations tend to occur in cell type-specific proteins. Thus, conserved core proteins in the transmission layer could perform a fundamental role in most cell types and are therefore less tolerant to germline mutations. In summary, we propose that the core signal transmission machinery is largely modulated by a variable input layer through physical protein interactions. We hypothesize that the bow-tie organization of cellular signaling on the level of protein abundance variability contributes to the specificity of the signal response in different cell types.

  20. Gear Wear Process Monitoring Using a Sideband Estimator Based on Modulation Signal Bispectrum

    Directory of Open Access Journals (Sweden)

    Ruiliang Zhang

    2017-03-01

    Full Text Available As one of the most common gear failure modes, tooth wear can produce nonlinear modulation sidebands in the vibration frequency spectrum. However, limited research has been reported in monitoring the gear wear based on vibration due to the lack of tools which can effectively extract the small sidebands. In order to accurately monitor gear wear progression in a timely fashion, this paper presents a gear wear condition monitoring approach based on vibration signal analysis using the modulation signal bispectrum-based sideband estimator (MSB-SE method. The vibration signals are collected using a run-to-failure test of gearbox under an accelerated test process. MSB analysis was performed on the vibration signals to extract the sideband information. Using a combination of the peak value of MSB-SE and the coherence of MSB-SE, the overall information of gear transmission system can be obtained. Based on the amplitude of MSB-SE peaks, a dimensionless indicator is proposed to assess the effects of gear tooth wear. The results demonstrated that the proposed indicator can be used to accurately and reliably monitor gear tooth wear and evaluate the wear severity.

  1. Bilateral collicular interaction: modulation of auditory signal processing in frequency domain.

    Science.gov (United States)

    Cheng, L; Mei, H-X; Tang, J; Fu, Z-Y; Jen, P H-S; Chen, Q-C

    2013-04-01

    In the ascending auditory pathway, the inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from a variety of lower auditory nuclei, intrinsic projections within the IC, contralateral IC through the commissure of the IC and the auditory cortex. All these connections make the IC a major center for subcortical temporal and spectral integration of auditory information. In this study, we examine bilateral collicular interaction in the modulation of frequency-domain signal processing of mice using electrophysiological recording and focal electrical stimulation. Focal electrical stimulation of neurons in one IC produces widespread inhibition and focused facilitation of responses of neurons in the other IC. This bilateral collicular interaction decreases the response magnitude and lengthens the response latency of inhibited IC neurons but produces an opposite effect on the response of facilitated IC neurons. In the frequency domain, the focal electrical stimulation of one IC sharpens or expands the frequency tuning curves (FTCs) of neurons in the other IC to improve frequency sensitivity and the frequency response range. The focal electrical stimulation also produces a shift in the best frequency (BF) of modulated IC (ICMdu) neurons toward that of electrically stimulated IC (ICES) neurons. The degree of bilateral collicular interaction is dependent upon the difference in the BF between the ICES neurons and ICMdu neurons. These data suggest that bilateral collicular interaction is a part of dynamic acoustic signal processing that adjusts and improves signal processing as well as reorganizes collicular representation of signal parameters according to the acoustic experience.

  2. Influenza Viral Manipulation of Sphingolipid Metabolism and Signaling to Modulate Host Defense System

    Directory of Open Access Journals (Sweden)

    Madhuvanthi Vijayan

    2014-01-01

    Full Text Available Viruses attempt to create a distinctive cellular environment to favor viral replication and spread. Recent studies uncovered new functions of the sphingolipid signaling/metabolism during pathogenic virus infections. While sphingolipids such as sphingomyelin and ceramide were reported to influence the entry step of several viruses, sphingolipid-metabolizing enzymes could directly alter viral replication processes. Influenza virus was shown to increase the level of sphingosine kinase (SK 1 to promote virus propagation. The mechanism involves regulation of intracellular signaling pathways, leading to the amplification of influenza viral RNA synthesis and nuclear export of viral ribonucleoprotein (RNP complex. However, bovine viral diarrhea virus inhibits SK1 to enhance the efficacy of virus replication, demonstrating the presence of virus-specific strategies for modulation of the sphingolipid system. Therefore, investigating the sphingolipid metabolism and signaling in the context of virus replication could help us design innovative therapeutic approaches to improve human health.

  3. LOV-Based Optogenetic Devices: Light-Driven Modules to Impart Photoregulated Control of Cellular Signaling

    Directory of Open Access Journals (Sweden)

    Ashutosh ePudasaini

    2015-05-01

    Full Text Available The Light-Oxygen-Voltage domain family of proteins is widespread in biology where they impart sensory responses to signal transduction domains. The small, light responsive LOV modules offer a novel platform for the construction of optogenetic tools. Currently, the design and implementation of these devices is partially hindered by a lack of understanding of how light drives allosteric changes in protein conformation to activate diverse signal transduction domains. Further, divergent photocycle properties amongst LOV family members complicate construction of highly sensitive devices with fast on/off kinetics. In the present review we discuss the history of LOV domain research with primary emphasis on tuning LOV domain chemistry and signal transduction to allow for improved optogenetic tools.

  4. LOV-based optogenetic devices: light-driven modules to impart photoregulated control of cellular signaling.

    Science.gov (United States)

    Pudasaini, Ashutosh; El-Arab, Kaley K; Zoltowski, Brian D

    2015-01-01

    The Light-Oxygen-Voltage domain family of proteins is widespread in biology where they impart sensory responses to signal transduction domains. The small, light responsive LOV modules offer a novel platform for the construction of optogenetic tools. Currently, the design and implementation of these devices is partially hindered by a lack of understanding of how light drives allosteric changes in protein conformation to activate diverse signal transduction domains. Further, divergent photocycle properties amongst LOV family members complicate construction of highly sensitive devices with fast on/off kinetics. In the present review we discuss the history of LOV domain research with primary emphasis on tuning LOV domain chemistry and signal transduction to allow for improved optogenetic tools.

  5. Signal line shapes of Fourier transform cavity-enhanced frequency modulation spectroscopy with optical frequency combs

    CERN Document Server

    Johansson, Alexandra C; Khodabakhsh, Amir; Foltynowicz, Aleksandra

    2016-01-01

    We present a thorough analysis of the signal line shapes of Fourier transform-based noise-immune cavity-enhanced optical frequency comb spectroscopy (NICE-OFCS). We discuss the signal dependence on the ratio of the modulation frequency, f${_m}$, to the molecular line width, {\\Gamma}. We compare a full model of the signals and a simplified absorption-like analytical model that has high accuracy for low f${_m}$/{\\Gamma} ratios and is much faster to compute. We verify the theory experimentally by measuring and fitting NICE-OFCS spectra of CO${_2}$ at 1575 nm using a system based on an Er:fiber femtosecond laser and a cavity with a finesse of ~11000.

  6. Modulation of leaf conductance by root to shoot signaling under water stress in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Fan Yi-juan; Liu Qing; Wei Kai-fa; Li Bing-bing; Ren Hui-bo; Gao Zhi-hui; Jia Wen-suo

    2006-01-01

    Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the establishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomatal movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying (PRD)experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid (ABA) of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance,which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf temperatures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further investigation into the molecular mechanisms of the root to shoot signaling under water stress.

  7. EpCAM modulates NF-κB signaling and interleukin-8 expression in breast cancer.

    Science.gov (United States)

    Sankpal, Narendra V; Fleming, Timothy P; Gillanders, William E

    2013-04-01

    The epithelial cell adhesion molecule (EpCAM) is a 40-kD type I transmembrane protein that is overexpressed in human epithelial cancers and is currently the target of molecular therapy based on its overexpression at the cell surface. Recently, we and others have shown a role for EpCAM in cell signaling and carcinogenesis, and EpCAM expression seems to promote breast cancer invasion. Interleukin-8 (IL-8/CXCL-8) is an inflammatory cytokine that has recently been shown to modulate breast cancer invasion and angiogenesis. In preliminary experiments, we identified a correlation between EpCAM and IL-8 expression in primary human breast cancers. Specific ablation of EpCAM in breast cancer cell lines results in decreased IL-8 expression, and IL-8 contributes to EpCAM-dependent breast cancer invasion. Specific ablation of EpCAM is also associated with decreased NF-κB transcription factor activity, decreased phosphorylation of the NF-κB family member RELA, and increased IκBα protein expression. EpCAM modulates IL-8 expression at baseline, and following IL-1β stimulation, which is known to be a potent inducer of NF-κB in breast cancer. In functional rescue experiments, specific ablation of RELA or forced expression of the NF-κB inhibitor protein IκBα prevented EpCAM-dependent rescue of IL-8 promoter activity. These studies show for the first time that EpCAM can modulate NF-κB transcription factor activity and IL-8 expression in breast cancer and confirm the role of EpCAM signaling in modulating breast cancer invasion. Further study is required to define the molecular mechanism(s) of EpCAM signaling in breast cancer and to direct the rational development of molecular therapies targeting EpCAM.

  8. Dopamine modulates acetylcholine release via octopamine and CREB signaling in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Satoshi Suo

    Full Text Available Animals change their behavior and metabolism in response to external stimuli. cAMP response element binding protein (CREB is a signal-activated transcription factor that enables the coupling of extracellular signals and gene expression to induce adaptive changes. Biogenic amine neurotransmitters regulate CREB and such regulation is important for long-term changes in various nervous system functions, including learning and drug addiction. In Caenorhabditis elegans, the amine neurotransmitter octopamine activates a CREB homolog, CRH-1, in cholinergic SIA neurons, whereas dopamine suppresses CREB activation by inhibiting octopamine signaling in response to food stimuli. However, the physiological role of this activation is unknown. In this study, the effect of dopamine, octopamine, and CREB on acetylcholine signaling was analyzed using the acetylcholinesterase inhibitor aldicarb. Mutants with decreased dopamine signaling exhibited reduced acetylcholine signaling, and octopamine and CREB functioned downstream of dopamine in this regulation. This study demonstrates that the regulation of CREB by amine neurotransmitters modulates acetylcholine release from the neurons of C. elegans.

  9. Optical Receiver for Coherently Detected Pulse-Position Modulated Signals in the Presence of Atmospheric Turbulence

    Science.gov (United States)

    Munoz Fernandez, M.; Vilnrotter, V. A.

    2005-05-01

    Performance analysis and experimental verification of a coherent free-space optical communications receiver in the presence of simulated atmospheric turbulence is presented. Bit-error rate (BER) performance of ideal coherent detection is analyzed in Section II, and the laboratory equipment and experimental setup used to carry out these experiments are described. The key components include two lasers operating at a 1064-nm wavelength for use with coherent detection, a 16-element (4 x 4) focal-plane detector array, and a data acquisition and signal processing assembly needed to sample and collect the data and analyze the results. The detected signals are combined using the least-mean-square (LMS) algorithm. In Section III, convergence of the algorithm for experimentally obtained signal tones in the presence of atmospheric turbulence is demonstrated. In Section IV, adaptive combining of experimentally obtained heterodyned pulse-position modulated (PPM) signals with pulse-to-pulse coherence, in the presence of simulated spatial distortions resembling atmospheric turbulence, is demonstrated. The adaptively combined PPM signals are phased up via an LMS algorithm suitably optimized to operate with PPM in the presence of additive shot noise. A convergence analysis of the algorithm is presented, and results with both computer-simulated and experimentally obtained PPM signals are analyzed.

  10. Evaluation of correlation property of linear-frequency-modulated signals coded by maximum-length sequences

    Science.gov (United States)

    Yamanaka, Kota; Hirata, Shinnosuke; Hachiya, Hiroyuki

    2016-07-01

    Ultrasonic distance measurement for obstacles has been recently applied in automobiles. The pulse-echo method based on the transmission of an ultrasonic pulse and time-of-flight (TOF) determination of the reflected echo is one of the typical methods of ultrasonic distance measurement. Improvement of the signal-to-noise ratio (SNR) of the echo and the avoidance of crosstalk between ultrasonic sensors in the pulse-echo method are required in automotive measurement. The SNR of the reflected echo and the resolution of the TOF are improved by the employment of pulse compression using a maximum-length sequence (M-sequence), which is one of the binary pseudorandom sequences generated from a linear feedback shift register (LFSR). Crosstalk is avoided by using transmitted signals coded by different M-sequences generated from different LFSRs. In the case of lower-order M-sequences, however, the number of measurement channels corresponding to the pattern of the LFSR is not enough. In this paper, pulse compression using linear-frequency-modulated (LFM) signals coded by M-sequences has been proposed. The coding of LFM signals by the same M-sequence can produce different transmitted signals and increase the number of measurement channels. In the proposed method, however, the truncation noise in autocorrelation functions and the interference noise in cross-correlation functions degrade the SNRs of received echoes. Therefore, autocorrelation properties and cross-correlation properties in all patterns of combinations of coded LFM signals are evaluated.

  11. Mindfulness training modulates value signals in ventromedial prefrontal cortex through input from insular cortex.

    Science.gov (United States)

    Kirk, Ulrich; Gu, Xiaosi; Harvey, Ann H; Fonagy, Peter; Montague, P Read

    2014-10-15

    Neuroimaging research has demonstrated that ventromedial prefrontal cortex (vmPFC) encodes value signals that can be modulated by top-down cognitive input such as semantic knowledge, price incentives, and monetary favors suggesting that such biases may have an identified biological basis. It has been hypothesized that mindfulness training (MT) provides one path for gaining control over such top-down influences; yet, there have been no direct tests of this hypothesis. Here, we probe the behavioral and neural effects of MT on value signals in vmPFC in a randomized longitudinal design of 8 weeks of MT on an initially naïve subject cohort. The impact of this within-subject training was assessed using two paradigms: one that employed primary rewards (fruit juice) in a simple conditioning task and another that used a well-validated art-viewing paradigm to test bias of monetary favors on preference. We show that MT behaviorally censors the top-down bias of monetary favors through a measurable influence on value signals in vmPFC. MT also modulates value signals in vmPFC to primary reward delivery. Using a separate cohort of subjects we show that 8 weeks of active control training (ACT) generates the same behavioral impact also through an effect on signals in the vmPFC. Importantly, functional connectivity analyses show that value signals in vmPFC are coupled with bilateral posterior insula in the MT groups in both paradigms, but not in the ACT groups. These results suggest that MT integrates interoceptive input from insular cortex in the context of value computations of both primary and secondary rewards.

  12. Cationic Polyamidoamine Dendrimers as Modulators of EGFR Signaling In Vitro and In Vivo.

    Science.gov (United States)

    Akhtar, Saghir; Al-Zaid, Bashayer; El-Hashim, Ahmed Z; Chandrasekhar, Bindu; Attur, Sreeja; Yousif, Mariam H M; Benter, Ibrahim F

    2015-01-01

    Cationic polyamidoamine (PAMAM) dendrimers are branch-like spherical polymers being investigated for a variety of applications in nanomedicine including nucleic acid drug delivery. Emerging evidence suggests they exhibit intrinsic biological and toxicological effects but little is known of their interactions with signal transduction pathways. We previously showed that the activated (fragmented) generation (G) 6 PAMAM dendrimer, Superfect (SF), stimulated epidermal growth factor receptor (EGFR) tyrosine kinase signaling-an important signaling cascade that regulates cell growth, survival and apoptosis- in cultured human embryonic kidney (HEK 293) cells. Here, we firstly studied the in vitro effects of Polyfect (PF), a non-activated (intact) G6 PAMAM dendrimer, on EGFR tyrosine kinase signaling via extracellular-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) in cultured HEK 293 cells and then compared the in vivo effects of a single administration (10mg/kg i.p) of PF or SF on EGFR signaling in the kidneys of normal and diabetic male Wistar rats. Polyfect exhibited a dose- and time-dependent inhibition of EGFR, ERK1/2 and p38 MAPK phosphorylation in HEK-293 cells similar to AG1478, a selective EGFR inhibitor. Administration of dendrimers to non-diabetic or diabetic animals for 24h showed that PF inhibited whereas SF stimulated EGFR phosphorylation in the kidneys of both sets of animals. PF-mediated inhibition of EGFR phosphorylation as well as SF or PF-mediated apoptosis in HEK 293 cells could be significantly reversed by co-treatment with antioxidants such as tempol implying that both these effects involved an oxidative stress-dependent mechanism. These results show for the first time that SF and PF PAMAM dendrimers can differentially modulate the important EGFR signal transduction pathway in vivo and may represent a novel class of EGFR modulators. These findings could have important clinical implications for the use of PAMAM dendrimers

  13. Leg muscle vibration modulates bodily self-consciousness: integration of proprioceptive, visual, and tactile signals.

    Science.gov (United States)

    Palluel, Estelle; Aspell, Jane Elizabeth; Blanke, Olaf

    2011-05-01

    Behavioral studies have used visuo-tactile conflicts between a participant's body and a visually presented fake or virtual body to investigate the importance of bodily perception for self-consciousness (bodily self-consciousness). Illusory self-identification with a fake body and changes in tactile processing--modulation of visuo-tactile cross-modal congruency effects (CCEs)--were reported in previous findings. Although proprioceptive signals are deemed important for bodily self-consciousness, their contribution to the representation of the full body has not been studied. Here we investigated whether and how self-identification and tactile processing (CCE magnitude) could be modified by altering proprioceptive signals with 80-Hz vibrations at the legs. Participants made elevation judgments of tactile cues (while ignoring nearby lights) during synchronous and asynchronous stroking of a seen fake body. We found that proprioceptive signals during vibrations altered the magnitude of self-identification and mislocalization of touch (CCE) in a synchrony-dependent fashion: we observed an increase of self-identification and CCE magnitude during asynchronous stroking. In a second control experiment we studied whether proprioceptive signals per se, or those from the lower limbs in particular, were essential for these changes. We applied vibrations at the upper limbs (which provide no information about the position of the participant's body in space) and in this case observed no modulation of bodily self-consciousness or tactile perception. These data link proprioceptive signals from the legs that are conveyed through the dorsal column-medial lemniscal pathway to bodily self-consciousness. We discuss their integration with bodily signals from vision and touch for full-body representations.

  14. Symmetric 10 Gb/s wavelength reused bidirectional RSOA based WDM-PON with DPSK modulated downstream and OFDM modulated upstream signals

    Science.gov (United States)

    Choudhury, Pallab K.; Khan, Tanvir Zaman

    2016-08-01

    A 10 Gb/s bidirectional wavelength division multiplexing passive optical network (WDM-PON) with reflective semiconductor optical amplifier (RSOA) based colorless optical network unit (ONU) is proposed and analyzed for next generation gigabit class optical access network. Differential phase shift keying (DPSK) modulated signal is used in downstream and further reused as a seeding wavelength for upstream data modulation. By exploiting the constant envelope property of DPSK seed signal, the re-modulation noise in upstream receiver is effectively minimized without employing any constraint on extinction ratio of downstream signal. Orthogonal frequency division multiplexing (OFDM) signal is used in upstream transmission to overcome the limited bandwidth (∼1 GHz) response of RSOA remodulation. The results show that the proposed 10 Gb/s symmetric WDM-PON can achieve good performance over 25 km fiber transmission with error free operation in downstream and bit error rate (BER) lower than forward error correction (FEC) limit in upstream.

  15. PARP-1 modulation of mTOR signaling in response to a DNA alkylating agent.

    Directory of Open Access Journals (Sweden)

    Chantal Ethier

    Full Text Available Poly(ADP-ribose polymerase-1 (PARP-1 is widely involved in cell death responses. Depending on the degree of injury and on cell type, PARP activation may lead to autophagy, apoptosis or necrosis. In HEK293 cells exposed to the alkylating agent N-methyl-N'-nitro-N'-nitrosoguanine (MNNG, we show that PARP-1 activation triggers a necrotic cell death response. The massive poly(ADP-ribose (PAR synthesis following PARP-1 activation leads to the modulation of mTORC1 pathway. Shortly after MNNG exposure, NAD⁺ and ATP levels decrease, while AMP levels drastically increase. We characterized at the molecular level the consequences of these altered nucleotide levels. First, AMP-activated protein kinase (AMPK is activated and the mTORC1 pathway is inhibited by the phosphorylation of Raptor, in an attempt to preserve cellular energy. Phosphorylation of the mTORC1 target S6 is decreased as well as the phosphorylation of the mTORC2 component Rictor on Thr1135. Finally, Akt phosphorylation on Ser473 is lost and then, cell death by necrosis occurs. Inhibition of PARP-1 with the potent PARP inhibitor AG14361 prevents all of these events. Moreover, the antioxidant N-acetyl-L-cysteine (NAC can also abrogate all the signaling events caused by MNNG exposure suggesting that reactive oxygen species (ROS production is involved in PARP-1 activation and modulation of mTOR signaling. In this study, we show that PARP-1 activation and PAR synthesis affect the energetic status of cells, inhibit the mTORC1 signaling pathway and possibly modulate the mTORC2 complex affecting cell fate. These results provide new evidence that cell death by necrosis is orchestrated by the balance between several signaling pathways, and that PARP-1 and PAR take part in these events.

  16. PARP-1 modulation of mTOR signaling in response to a DNA alkylating agent.

    Science.gov (United States)

    Ethier, Chantal; Tardif, Maxime; Arul, Laura; Poirier, Guy G

    2012-01-01

    Poly(ADP-ribose) polymerase-1 (PARP-1) is widely involved in cell death responses. Depending on the degree of injury and on cell type, PARP activation may lead to autophagy, apoptosis or necrosis. In HEK293 cells exposed to the alkylating agent N-methyl-N'-nitro-N'-nitrosoguanine (MNNG), we show that PARP-1 activation triggers a necrotic cell death response. The massive poly(ADP-ribose) (PAR) synthesis following PARP-1 activation leads to the modulation of mTORC1 pathway. Shortly after MNNG exposure, NAD⁺ and ATP levels decrease, while AMP levels drastically increase. We characterized at the molecular level the consequences of these altered nucleotide levels. First, AMP-activated protein kinase (AMPK) is activated and the mTORC1 pathway is inhibited by the phosphorylation of Raptor, in an attempt to preserve cellular energy. Phosphorylation of the mTORC1 target S6 is decreased as well as the phosphorylation of the mTORC2 component Rictor on Thr1135. Finally, Akt phosphorylation on Ser473 is lost and then, cell death by necrosis occurs. Inhibition of PARP-1 with the potent PARP inhibitor AG14361 prevents all of these events. Moreover, the antioxidant N-acetyl-L-cysteine (NAC) can also abrogate all the signaling events caused by MNNG exposure suggesting that reactive oxygen species (ROS) production is involved in PARP-1 activation and modulation of mTOR signaling. In this study, we show that PARP-1 activation and PAR synthesis affect the energetic status of cells, inhibit the mTORC1 signaling pathway and possibly modulate the mTORC2 complex affecting cell fate. These results provide new evidence that cell death by necrosis is orchestrated by the balance between several signaling pathways, and that PARP-1 and PAR take part in these events.

  17. The Biological Function of the Prion Protein: A Cell Surface Scaffold of Signaling Modules

    Science.gov (United States)

    Linden, Rafael

    2017-01-01

    The prion glycoprotein (PrPC) is mostly located at the cell surface, tethered to the plasma membrane through a glycosyl-phosphatydil inositol (GPI) anchor. Misfolding of PrPC is associated with the transmissible spongiform encephalopathies (TSEs), whereas its normal conformer serves as a receptor for oligomers of the β-amyloid peptide, which play a major role in the pathogenesis of Alzheimer’s Disease (AD). PrPC is highly expressed in both the nervous and immune systems, as well as in other organs, but its functions are controversial. Extensive experimental work disclosed multiple physiological roles of PrPC at the molecular, cellular and systemic levels, affecting the homeostasis of copper, neuroprotection, stem cell renewal and memory mechanisms, among others. Often each such process has been heralded as the bona fide function of PrPC, despite restricted attention paid to a selected phenotypic trait, associated with either modulation of gene expression or to the engagement of PrPC with a single ligand. In contrast, the GPI-anchored prion protein was shown to bind several extracellular and transmembrane ligands, which are required to endow that protein with the ability to play various roles in transmembrane signal transduction. In addition, differing sets of those ligands are available in cell type- and context-dependent scenarios. To account for such properties, we proposed that PrPC serves as a dynamic platform for the assembly of signaling modules at the cell surface, with widespread consequences for both physiology and behavior. The current review advances the hypothesis that the biological function of the prion protein is that of a cell surface scaffold protein, based on the striking similarities of its functional properties with those of scaffold proteins involved in the organization of intracellular signal transduction pathways. Those properties are: the ability to recruit spatially restricted sets of binding molecules involved in specific signaling

  18. Tandem demodulation lock-in amplifier based on digital signal processor for dual-modulated spectroscopy.

    Science.gov (United States)

    Qin, Jianhuan; Huang, Zhiming; Ge, Yujian; Hou, Yun; Chu, Junhao

    2009-03-01

    Dual-modulated spectroscopy is one of the most powerful methods in the measurement of modulation spectroscopy. Here we develop a tandem lock-in amplifier (LIA) based on digital signal processor to implement a novel algorithm of tandem demodulation. The theoretical analysis of demodulation algorithm is presented, and the implementation of this tandem LIA is described in detail. Compared to the traditional demodulating way with two LIAs in cascade, this tandem LIA eliminates the extra quantization error of redundant analog-to-digital and digital-to-analog conversions and removes the limitation to the time constant in the commercial LIA, hence lowers the requirement of frequency ratio in dual-modulated spectroscopy. The applications are given as examples in the photoreflectance (PR) measurements of GaAs (100) thin film and GaSb bulk material, respectively, at the different optical energy regions. The experimental results indicate that this tandem is well capable of PR spectra measurement with good PR lineshapes and reasonable signal noise ratio. A brief comparison of GaAs PR results between tandem LIA and two LIAs is made to prove the efficiency and advantages of the tandem LIA.

  19. Robustness of digitally modulated signal features against variation in HF noise model

    Directory of Open Access Journals (Sweden)

    Shoaib Mobien

    2011-01-01

    Full Text Available Abstract High frequency (HF band has both military and civilian uses. It can be used either as a primary or backup communication link. Automatic modulation classification (AMC is of an utmost importance in this band for the purpose of communications monitoring; e.g., signal intelligence and spectrum management. A widely used method for AMC is based on pattern recognition (PR. Such a method has two main steps: feature extraction and classification. The first step is generally performed in the presence of channel noise. Recent studies show that HF noise could be modeled by Gaussian or bi-kappa distributions, depending on day-time. Therefore, it is anticipated that change in noise model will have impact on features extraction stage. In this article, we investigate the robustness of well known digitally modulated signal features against variation in HF noise. Specifically, we consider temporal time domain (TTD features, higher order cumulants (HOC, and wavelet based features. In addition, we propose new features extracted from the constellation diagram and evaluate their robustness against the change in noise model. This study is targeting 2PSK, 4PSK, 8PSK, 16QAM, 32QAM, and 64QAM modulations, as they are commonly used in HF communications.

  20. Rectification is required to extract oscillatory envelope modulation from surface electromyographic signals.

    Science.gov (United States)

    Dakin, Christopher J; Dalton, Brian H; Luu, Billy L; Blouin, Jean-Sébastien

    2014-10-01

    Rectification of surface electromyographic (EMG) recordings prior to their correlation with other signals is a widely used form of preprocessing. Recently this practice has come into question, elevating the subject of EMG rectification to a topic of much debate. Proponents for rectifying suggest it accentuates the EMG spike timing information, whereas opponents indicate it is unnecessary and its nonlinear distortion of data is potentially destructive. Here we examine the necessity of rectification on the extraction of muscle responses, but for the first time using a known oscillatory input to the muscle in the form of electrical vestibular stimulation. Participants were exposed to sinusoidal vestibular stimuli while surface and intramuscular EMG were recorded from the left medial gastrocnemius. We compared the unrectified and rectified surface EMG to single motor units to determine which method best identified stimulus-EMG coherence and phase at the single-motor unit level. Surface EMG modulation at the stimulus frequency was obvious in the unrectified surface EMG. However, this modulation was not identified by the fast Fourier transform, and therefore stimulus coherence with the unrectified EMG signal failed to capture this covariance. Both the rectified surface EMG and single motor units displayed significant coherence over the entire stimulus bandwidth (1-20 Hz). Furthermore, the stimulus-phase relationship for the rectified EMG and motor units shared a moderate correlation (r = 0.56). These data indicate that rectification of surface EMG is a necessary step to extract EMG envelope modulation due to motor unit entrainment to a known stimulus.

  1. Diverse feather shape evolution enabled by coupling anisotropic signalling modules with self-organizing branching programme

    Science.gov (United States)

    Li, Ang; Figueroa, Seth; Jiang, Ting-Xin; Wu, Ping; Widelitz, Randall; Nie, Qing; Chuong, Cheng-Ming

    2017-01-01

    Adaptation of feathered dinosaurs and Mesozoic birds to new ecological niches was potentiated by rapid diversification of feather vane shapes. The molecular mechanism driving this spectacular process remains unclear. Here, through morphology analysis, transcriptome profiling, functional perturbations and mathematical simulations, we find that mesenchyme-derived GDF10 and GREM1 are major controllers for the topologies of rachidial and barb generative zones (setting vane boundaries), respectively, by tuning the periodic-branching programme of epithelial progenitors. Their interactions with the anterior–posterior WNT gradient establish the bilateral-symmetric vane configuration. Additionally, combinatory effects of CYP26B1, CRABP1 and RALDH3 establish dynamic retinoic acid (RA) landscapes in feather mesenchyme, which modulate GREM1 expression and epithelial cell shapes. Incremental changes of RA gradient slopes establish a continuum of asymmetric flight feathers along the wing, while switch-like modulation of RA signalling confers distinct vane shapes between feather tracts. Therefore, the co-option of anisotropic signalling modules introduced new dimensions of feather shape diversification. PMID:28106042

  2. Hippocampal Mismatch Signals Are Modulated by the Strength of Neural Predictions and Their Similarity to Outcomes.

    Science.gov (United States)

    Long, Nicole M; Lee, Hongmi; Kuhl, Brice A

    2016-12-14

    The hippocampus is thought to compare predicted events with current perceptual input, generating a mismatch signal when predictions are violated. However, most prior studies have only inferred when predictions occur without measuring them directly. Moreover, an important but unresolved question is whether hippocampal mismatch signals are modulated by the degree to which predictions differ from outcomes. Here, we conducted a human fMRI study in which subjects repeatedly studied various word-picture pairs, learning to predict particular pictures (outcomes) from the words (cues). After initial learning, a subset of cues was paired with a novel, unexpected outcome, whereas other cues continued to predict the same outcome. Critically, when outcomes changed, the new outcome was either "near" to the predicted outcome (same visual category as the predicted picture) or "far" from the predicted outcome (different visual category). Using multivoxel pattern analysis, we indexed cue-evoked reactivation (prediction) within neocortical areas and related these trial-by-trial measures of prediction strength to univariate hippocampal responses to the outcomes. We found that prediction strength positively modulated hippocampal responses to unexpected outcomes, particularly when unexpected outcomes were close, but not identical, to the prediction. Hippocampal responses to unexpected outcomes were also associated with a tradeoff in performance during a subsequent memory test: relatively faster retrieval of new (updated) associations, but relatively slower retrieval of the original (older) associations. Together, these results indicate that hippocampal mismatch signals reflect a comparison between active predictions and current outcomes and that these signals are most robust when predictions are similar, but not identical, to outcomes. Although the hippocampus is widely thought to signal "mismatches" between memory-based predictions and outcomes, previous research has not linked

  3. Small-molecule modulators of Hedgehog signaling: identification and characterization of Smoothened agonists and antagonists

    Directory of Open Access Journals (Sweden)

    Shulok Janine

    2002-11-01

    Full Text Available Abstract Background The Hedgehog (Hh signaling pathway is vital to animal development as it mediates the differentiation of multiple cell types during embryogenesis. In adults, Hh signaling can be activated to facilitate tissue maintenance and repair. Moreover, stimulation of the Hh pathway has shown therapeutic efficacy in models of neuropathy. The underlying mechanisms of Hh signal transduction remain obscure, however: little is known about the communication between the pathway suppressor Patched (Ptc, a multipass transmembrane protein that directly binds Hh, and the pathway activator Smoothened (Smo, a protein that is related to G-protein-coupled receptors and is capable of constitutive activation in the absence of Ptc. Results We have identified and characterized a synthetic non-peptidyl small molecule, Hh-Ag, that acts as an agonist of the Hh pathway. This Hh agonist promotes cell-type-specific proliferation and concentration-dependent differentiation in vitro, while in utero it rescues aspects of the Hh-signaling defect in Sonic hedgehog-null, but not Smo-null, mouse embryos. Biochemical studies with Hh-Ag, the Hh-signaling antagonist cyclopamine, and a novel Hh-signaling inhibitor Cur61414, reveal that the action of all these compounds is independent of Hh-protein ligand and of the Hh receptor Ptc, as each binds directly to Smo. Conclusions Smo can have its activity modulated directly by synthetic small molecules. These studies raise the possibility that Hh signaling may be regulated by endogenous small molecules in vivo and provide potent compounds with which to test the therapeutic value of activating the Hh-signaling pathway in the treatment of traumatic and chronic degenerative conditions.

  4. Frequency modulator. Transmission of meteorological signals in LVC; Modulador de frecuencia. Transmision de senales meteorologicas en CLV

    Energy Technology Data Exchange (ETDEWEB)

    Rivero G, P.T.; Ramirez S, R.; Gonzalez M, J.L.; Rojas N, P.; Celis del Angel, L. [ININ, 52750 La marquesa, Estado de Mexico (Mexico)

    2007-07-01

    The development of the frequency modulator and demodulator circuit for transmission of meteorological signals by means of fiber optics of the meteorology station to the nuclear reactor unit 1 in the Laguna Verde Central in Veracruz is described. (Author)

  5. Optical Nuclear Polarization in the Excited State Through Cross-Relaxation and Its Use in the Study of the Carbon-13 Hyperfine Coupling in the Lowest Triplet State of 1-13C-p-Benzoquinone

    NARCIS (Netherlands)

    Lichtenbelt, Jan H.; Fremeijer, Jan G.F.M.; Wiersma, Douwe A.

    1976-01-01

    In this paper the phenomenon of optical nuclear polarization in the excited state through cross-relaxation is described. It is shown that when the populating and depopulating rates of the triplet spin sublevels are known the absolute nuclear polarizations can be calculated and that optical detection

  6. Modulating the actin cytoskeleton affects mechanically induced signal transduction and differentiation in mesenchymal stem cells.

    Directory of Open Access Journals (Sweden)

    Petra Müller

    Full Text Available Mechanical interactions of mesenchymal stem cells (MSC with the environment play a significant role in controlling the diverse biological functions of these cells. Mechanical forces are transduced by integrins to the actin cytoskeleton that functions as a scaffold to switch mechanical signals into biochemical pathways. To explore the significance of cytoskeletal mechanisms in human MSC we modulated the actin cytoskeleton using the depolymerising drugs cytochalasin D (CytD and latrunculin A (LatA, as well as the stabilizing drug jasplakinolide (Jasp and examined the activation of the signalling molecules ERK and AKT during mechanical loading. All three drugs provoked significant changes in cell morphology and organisation of the cytoskeleton. Application of mechanical forces to β1-integrin receptors using magnetic beads without deformation of the cell shape induced a phosphorylation of ERK and AKT. Of the two drugs that inhibited the cytoskeletal polymerization, LatA completely blocked the activation of ERK and AKT due to mechanical forces, whereas CytD inhibited the activation of AKT but not of ERK. Activation of both signalling molecules by integrin loading was not affected due to cell treatment with the cytoskeleton stabilizing drug Jasp. To correlate the effects of the drugs on mechanically induced activation of AKT and ERK with parameters of MSC differentiation, we studied ALP activity as a marker for osteogenic differentiation and examined the uptake of fat droplets as marker for adipogenic differentiation in the presence of the drugs. All three drugs inhibited ALP activity of MSC in osteogenic differentiation medium. Adipogenic differentiation was enhanced by CytD and Jasp, but not by LatA. The results indicate that modulation of the cytoskeleton using perturbing drugs can differentially modify both mechanically induced signal transduction and MSC differentiation. In addition to activation of the signalling molecules ERK and AKT, other

  7. Deciphering and modulating G protein signalling in C. elegans using the DREADD technology

    Science.gov (United States)

    Prömel, Simone; Fiedler, Franziska; Binder, Claudia; Winkler, Jana; Schöneberg, Torsten; Thor, Doreen

    2016-01-01

    G-protein signalling is an evolutionary conserved concept highlighting its fundamental impact on developmental and functional processes. Studies on the effects of G protein signals on tissues as well as an entire organism are often conducted in Caenorhabditis elegans. To understand and control dynamics and kinetics of the processes involved, pharmacological modulation of specific G protein pathways would be advantageous, but is difficult due to a lack in accessibility and regulation. To provide this option, we designed G protein-coupled receptor-based designer receptors (DREADDs) for C. elegans. Initially described in mammalian systems, these modified muscarinic acetylcholine receptors are activated by the inert drug clozapine-N-oxide, but not by their endogenous agonists. We report a novel C. elegans-specific DREADD, functionally expressed and specifically activating Gq-protein signalling in vitro and in vivo which we used for modulating mating behaviour. Therefore, this novel designer receptor demonstrates the possibility to pharmacologically control physiological functions in C. elegans. PMID:27461895

  8. The Parkinson's Disease-Associated Protein Kinase LRRK2 Modulates Notch Signaling through the Endosomal Pathway.

    Directory of Open Access Journals (Sweden)

    Yuzuru Imai

    2015-09-01

    Full Text Available Leucine-rich repeat kinase 2 (LRRK2 is a key molecule in the pathogenesis of familial and idiopathic Parkinson's disease (PD. We have identified two novel LRRK2-associated proteins, a HECT-type ubiquitin ligase, HERC2, and an adaptor-like protein with six repeated Neuralized domains, NEURL4. LRRK2 binds to NEURL4 and HERC2 via the LRRK2 Ras of complex proteins (ROC domain and NEURL4, respectively. HERC2 and NEURL4 link LRRK2 to the cellular vesicle transport pathway and Notch signaling, through which the LRRK2 complex promotes the recycling of the Notch ligand Delta-like 1 (Dll1/Delta (Dl through the modulation of endosomal trafficking. This process negatively regulates Notch signaling through cis-inhibition by stabilizing Dll1/Dl, which accelerates neural stem cell differentiation and modulates the function and survival of differentiated dopaminergic neurons. These effects are strengthened by the R1441G ROC domain-mutant of LRRK2. These findings suggest that the alteration of Notch signaling in mature neurons is a component of PD etiology linked to LRRK2.

  9. A TRPV2–PKA Signaling Module for Transduction of Physical Stimuli in Mast Cells

    Science.gov (United States)

    Stokes, Alexander J.; Shimoda, Lori M.N.; Koblan-Huberson, Murielle; Adra, Chaker N.; Turner, Helen

    2004-01-01

    Cutaneous mast cell responses to physical (thermal, mechanical, or osmotic) stimuli underlie the pathology of physical urticarias. In vitro experiments suggest that mast cells respond directly to these stimuli, implying that a signaling mechanism couples functional responses to physical inputs in mast cells. We asked whether transient receptor potential (vanilloid) (TRPV) cation channels were present and functionally coupled to signaling pathways in mast cells, since expression of this channel subfamily confers sensitivity to thermal, osmotic, and pressure inputs. Transcripts for a range of TRPVs were detected in mast cells, and we report the expression, surface localization, and oligomerization of TRPV2 protein subunits in these cells. We describe the functional coupling of TRPV2 protein to calcium fluxes and proinflammatory degranulation events in mast cells. In addition, we describe a novel protein kinase A (PKA)–dependent signaling module, containing PKA and a putative A kinase adapter protein, Acyl CoA binding domain protein (ACBD)3, that interacts with TRPV2 in mast cells. We propose that regulated phosphorylation by PKA may be a common pathway for TRPV modulation. PMID:15249591

  10. Modulation identification on OFDM burst signal%突发OFDM信号调制识别

    Institute of Scientific and Technical Information of China (English)

    李国汉; 王可人; 刘世春

    2012-01-01

    Gaussianily test is employed to the OFDM modulation identification,but it can not distinguish OFDM from Gaussian noise.In order to solve the ploblem, a KS test statistics after Multi-Bands-Entropy based endpoint detection on OFDM signal is proposed in this paper.The results of simulation and analysis shows Multi-Bands-Entropy based method effectively achieves OFDM signal endpoint detection,and thanks to endpoint detection,the KS statistics reduces the alarm probability caused by pure noise,improves performance of OFDM identification.The method presented in this paper can achieve OFDM burst signal modulation identification.%为了对OFDM信号进行识别,针对高斯性检测法无法识别白噪声和OFDM信号的问题,提出先应用多子带谱熵法进行OFDM信号端点检测,再构造KS检验统计量进行OFDM信号识别的方案.理论分析及仿真结果表明,多子带谱熵法能够有效地进行OFDM信号的端点检测,基于端点检测的KS统计量降低了纯噪声信号带来的虚警,进而提高了对OFDM信号的识别能力,可以有效地进行突发OFDM信号的识别.

  11. Astrophysics-independent bounds on the annual modulation of dark matter signals.

    Science.gov (United States)

    Herrero-Garcia, Juan; Schwetz, Thomas; Zupan, Jure

    2012-10-05

    We show how constraints on the time integrated event rate from a given dark matter (DM) direct detection experiment can be used to bound the amplitude of the annual modulation signal in another experiment. The method requires only mild assumptions about the properties of the local DM distribution: that it is temporally stable on the scale of months and spatially homogeneous on the ecliptic. We apply the method to the annual modulation signal in DAMA/LIBRA, which we compare to the bounds derived from XENON10, XENON100, cryogenic DM search, and SIMPLE data. Assuming a DM mass of 10 GeV, we show that under the above assumptions about the DM halo, a DM interpretation of the DAMA/LIBRA signal is excluded for several classes of models: at 6.3σ (4.6σ) for elastic isospin conserving (violating) spin-independent interactions, and at 4.9σ for elastic spin-dependent interactions on protons.

  12. Role of Suppressor of Cytokine Signaling 3 in the Immune Modulation of Mesenchymal Stromal Cells.

    Science.gov (United States)

    Yang, Chen; Zheng, Chunquan; Lin, Hai; Li, Jing; Zhao, Keqing

    2016-02-01

    The underlying mechanisms of mesenchymal stromal cells (MSCs) on immune modulation to treat allergic diseases remain unclear. Here, we showed that the suppressor of cytokine signaling 3 (SOCS3) is an important immune modulator expressed by MSCs, which is significantly increased by interferon-γ (IFN-γ). In addition, we observed that SOCS3 is a crucial mediator of the anti-proliferative and functional effects of MSCs on T cells and B cells. The immune modulation of MSCs through SOCS3 is mediated by cell-cell contacts. Moreover, SOCS3 could serve as an indicator to predict the potential immune modulatory of MSCs derived from different donors. Furthermore, treatment with anti-SOCS3 Ab significantly decreased ovalbumin-specific antibodies and neutrophil infiltration in ovalbumin-induced allergic rhinitis (AR) mice. Our results suggest that SOCS3 serves as an immune modulator interfering with T cells and B cells, and SOCS3 may act as a predictive marker for immune modulatory of MSCs.

  13. A FAK-Cas-Rac-lamellipodin signaling module transduces extracellular matrix stiffness into mechanosensitive cell cycling.

    Science.gov (United States)

    Bae, Yong Ho; Mui, Keeley L; Hsu, Bernadette Y; Liu, Shu-Lin; Cretu, Alexandra; Razinia, Ziba; Xu, Tina; Puré, Ellen; Assoian, Richard K

    2014-06-17

    Tissue and extracellular matrix (ECM) stiffness is transduced into intracellular stiffness, signaling, and changes in cellular behavior. Integrins and several of their associated focal adhesion proteins have been implicated in sensing ECM stiffness. We investigated how an initial sensing event is translated into intracellular stiffness and a biologically interpretable signal. We found that a pathway consisting of focal adhesion kinase (FAK), the adaptor protein p130Cas (Cas), and the guanosine triphosphatase Rac selectively transduced ECM stiffness into stable intracellular stiffness, increased the abundance of the cell cycle protein cyclin D1, and promoted S-phase entry. Rac-dependent intracellular stiffening involved its binding partner lamellipodin, a protein that transmits Rac signals to the cytoskeleton during cell migration. Our findings establish that mechanotransduction by a FAK-Cas-Rac-lamellipodin signaling module converts the external information encoded by ECM stiffness into stable intracellular stiffness and mechanosensitive cell cycling. Thus, lamellipodin is important not only in controlling cellular migration but also for regulating the cell cycle in response to mechanical signals.

  14. Phase Clustering Based Modulation Classification Algorithm for PSK Signal over Wireless Environment

    Directory of Open Access Journals (Sweden)

    Qi An

    2016-01-01

    Full Text Available Promptitude and accuracy of signals’ non-data-aided (NDA identification is one of the key technology demands in noncooperative wireless communication network, especially in information monitoring and other electronic warfare. Based on this background, this paper proposes a new signal classifier for phase shift keying (PSK signals. The periodicity of signal’s phase is utilized as the assorted character, with which a fractional function is constituted for phase clustering. Classification and the modulation order of intercepted signals can be achieved through its Fast Fourier Transform (FFT of the phase clustering function. Frequency offset is also considered for practical conditions. The accuracy of frequency offset estimation has a direct impact on its correction. Thus, a feasible solution is supplied. In this paper, an advanced estimator is proposed for estimating the frequency offset and balancing estimation accuracy and range under low signal-to-noise ratio (SNR conditions. The influence on estimation range brought by the maximum correlation interval is removed through the differential operation of the autocorrelation of the normalized baseband signal raised to the power of Q. Then, a weighted summation is adopted for an effective frequency estimation. Details of equations and relevant simulations are subsequently presented. The estimator proposed can reach an estimation accuracy of 10-4 even when the SNR is as low as -15 dB. Analytical formulas are expressed, and the corresponding simulations illustrate that the classifier proposed is more efficient than its counterparts even at low SNRs.

  15. β-Adrenergic receptor signaling and modulation of long-term potentiation in the mammalian hippocampus.

    Science.gov (United States)

    O'Dell, Thomas J; Connor, Steven A; Guglietta, Ryan; Nguyen, Peter V

    2015-09-01

    Encoding new information in the brain requires changes in synaptic strength. Neuromodulatory transmitters can facilitate synaptic plasticity by modifying the actions and expression of specific signaling cascades, transmitter receptors and their associated signaling complexes, genes, and effector proteins. One critical neuromodulator in the mammalian brain is norepinephrine (NE), which regulates multiple brain functions such as attention, perception, arousal, sleep, learning, and memory. The mammalian hippocampus receives noradrenergic innervation and hippocampal neurons express β-adrenergic receptors, which are known to play important roles in gating the induction of long-lasting forms of synaptic potentiation. These forms of long-term potentiation (LTP) are believed to importantly contribute to long-term storage of spatial and contextual memories in the brain. In this review, we highlight the contributions of noradrenergic signaling in general and β-adrenergic receptors in particular, toward modulating hippocampal LTP. We focus on the roles of NE and β-adrenergic receptors in altering the efficacies of specific signaling molecules such as NMDA and AMPA receptors, protein phosphatases, and translation initiation factors. Also, the roles of β-adrenergic receptors in regulating synaptic "tagging" and "capture" of LTP within synaptic networks of the hippocampus are reviewed. Understanding the molecular and cellular bases of noradrenergic signaling will enrich our grasp of how the brain makes new, enduring memories, and may shed light on credible strategies for improving mental health through treatment of specific disorders linked to perturbed memory processing and dysfunctional noradrenergic synaptic transmission.

  16. 40 Gbit/s serial data signal regeneration using self-phase modulation in a silicon nanowire

    DEFF Research Database (Denmark)

    Ji, Hua; Wang, Ju; Hu, Hao

    2012-01-01

    We experimentally demonstrate self-phase modulation based all-optical regeneration of a 40 Gbit/s serial data signal in a silicon nanowire. Bit error rate characterization shows 2 dB receiver power improvement.......We experimentally demonstrate self-phase modulation based all-optical regeneration of a 40 Gbit/s serial data signal in a silicon nanowire. Bit error rate characterization shows 2 dB receiver power improvement....

  17. A 1V low power second-order delta-sigma modulator for biomedical signal application.

    Science.gov (United States)

    Hsu, Chih-Han; Tang, Kea-Tiong

    2013-01-01

    This paper presents the design and implementation of a low-power delta-sigma modulator for biomedical application with a standard 90 nm CMOS technology. The delta-sigma architecture is implemented as 2nd order feedforward architecture. A low quiescent current operational transconductance amplifier (OTA) is utilized to reduce power consumption. This delta-sigma modulator operated in 1V power supply, and achieved 64.87 dB signal to noise distortion ratio (SNDR) at 10 KHz bandwidth with an oversampling ratio (OSR) of 64. The power consumption is 17.14 µW, and the figure-of-merit (FOM) is 0.60 pJ/conv.

  18. Response and fluctuations of a two-state signaling module with feedback

    CERN Document Server

    Gopalakrishnan, Manoj; Jülicher, Frank; Zapotocky, Martin

    2007-01-01

    We study the stochastic kinetics of a signaling module consisting of a two-state stochastic point process with negative feedback. In the active state, a product is synthesized which increases the active-to-inactive transition rate of the process. We analyze this simple autoregulatory module using a path-integral technique based on the temporal statistics of state flips of the process. We develop a systematic framework to calculate averages, autocorrelations, and response functions by treating the feedback as a weak perturbation. Explicit analytical results are obtained to first order in the feedback strength. Monte Carlo simulations are performed to test the analytical results in the weak feedback limit and to investigate the strong feedback regime. We conclude by relating some of our results to experimental observations in the olfactory and visual sensory systems.

  19. Custom Chipset and Compact Module Design for a 75-110 GHz Laboratory Signal Source

    CERN Document Server

    Morgan, Matthew A; Castro, Jason J

    2016-01-01

    We report on the development and characterization of a compact, full-waveguide bandwidth (WR-10) signal source for general-purpose testing of mm-wave components. The MMIC-based multichip module is designed for compactness and ease-of-use, especially in size-constrained test sets such as a wafer probe station. It takes as input a cm-wave CW reference and provides a factor of three frequency multiplication as well as amplification, output power adjustment, and in-situ output power monitoring. It utilizes a number of custom MMIC chips such as a Schottky-diode limiter and a broadband mm-wave detector, both designed explicitly for this module, as well as custom millimeter-wave multipliers and amplifiers reported in previous papers.

  20. Reconstruction of the first derivative EPR spectrum from multiple harmonics of the field-modulated continuous wave signal

    Science.gov (United States)

    Tseitlin, Mark; Eaton, Sandra S.; Eaton, Gareth R.

    2011-01-01

    Selection of the amplitude of magnetic field modulation for continuous wave electron paramagnetic resonance (EPR) often is a trade-off between sensitivity and resolution. Increasing the modulation amplitude improves the signal-to-noise ratio, S/N, at the expense of broadening the signal. Combining information from multiple harmonics of the field-modulated signal is proposed as a method to obtain the first derivative spectrum with minimal broadening and improved signal-to-noise. The harmonics are obtained by digital phase-sensitive detection of the signal at the modulation frequency and its integer multiples. Reconstruction of the first derivative EPR line is done in the Fourier conjugate domain where each harmonic can be represented as the product of the Fourier transform of the 1st derivative signal with an analytical function. The analytical function for each harmonic can be viewed as a filter. The Fourier transform of the 1st derivative spectrum can be calculated from all available harmonics by solving an optimization problem with the goal of maximizing the S/N. Inverse Fourier transformation of the result produces the 1st derivative EPR line in the magnetic field domain. The use of modulation amplitude greater than linewidth improves the S/N, but does not broaden the reconstructed spectrum. The method works for an arbitrary EPR line shape, but is limited to the case when magnetization instantaneously follows the modulation field, which is known as the adiabatic approximation. PMID:21349750

  1. Adenosine receptor signaling modulates permeability of the blood-brain barrier.

    Science.gov (United States)

    Carman, Aaron J; Mills, Jeffrey H; Krenz, Antje; Kim, Do-Geun; Bynoe, Margaret S

    2011-09-14

    The blood-brain barrier (BBB) is comprised of specialized endothelial cells that form the capillary microvasculature of the CNS and is essential for brain function. It also poses the greatest impediment in the treatment of many CNS diseases because it commonly blocks entry of therapeutic compounds. Here we report that adenosine receptor (AR) signaling modulates BBB permeability in vivo. A(1) and A(2A) AR activation facilitated the entry of intravenously administered macromolecules, including large dextrans and antibodies to β-amyloid, into murine brains. Additionally, treatment with an FDA-approved selective A(2A) agonist, Lexiscan, also increased BBB permeability in murine models. These changes in BBB permeability are dose-dependent and temporally discrete. Transgenic mice lacking A(1) or A(2A) ARs showed diminished dextran entry into the brain after AR agonism. Following treatment with a broad-spectrum AR agonist, intravenously administered anti-β-amyloid antibody was observed to enter the CNS and bind β-amyloid plaques in a transgenic mouse model of Alzheimer's disease (AD). Selective AR activation resulted in cellular changes in vitro including decreased transendothelial electrical resistance, increased actinomyosin stress fiber formation, and alterations in tight junction molecules. These results suggest that AR signaling can be used to modulate BBB permeability in vivo to facilitate the entry of potentially therapeutic compounds into the CNS. AR signaling at brain endothelial cells represents a novel endogenous mechanism of modulating BBB permeability. We anticipate these results will aid in drug design, drug delivery and treatment options for neurological diseases such as AD, Parkinson's disease, multiple sclerosis and cancers of the CNS.

  2. Endocannabinoid-dependent modulation of phasic dopamine signaling encodes external and internal reward-predictive cues.

    Science.gov (United States)

    Wenzel, Jennifer M; Cheer, Joseph F

    2014-01-01

    The mesolimbic dopamine (DA) system plays an integral role in incentive motivation and reward seeking and a growing body of evidence identifies signal transduction at cannabinoid receptors as a critical modulator of this system. Indeed, administration of exogenous cannabinoids results in burst firing of DA neurons of the ventral tegmental area and increases extracellular DA in the nucleus accumbens (NAcc). Implementation of fast-scan cyclic voltammetry (FSCV) confirms the ability of cannabinoids to augment DA within the NAcc on a subsecond timescale. The use of FSCV along with newly developed highly selective pharmacological compounds advances our understanding of how cannabinoids influence DA transmission and highlights a role for endocannabinoid-modulated subsecond DAergic activation in the incentive motivational properties of not only external, but also internal reward-predictive cues. For example, our laboratory has recently demonstrated that in mice responding under a fixed-interval (FI) schedule for food reinforcement, fluctuations in NAcc DA signal the principal cue predictive of reinforcer availability - time. That is, as the interval progresses, NAcc DA levels decline leading to accelerated food seeking and the resulting characteristic FI scallop pattern of responding. Importantly, administration of WIN 55,212-2, a synthetic cannabinoid agonist, or JZL184, an indirect cannabinoid agonist, increases DA levels during the interval and disrupts this pattern of responding. Along with a wealth of other reports, these results illustrate the role of cannabinoid receptor activation in the regulation of DA transmission and the control of temporally guided reward seeking. The current review will explore the striatal beat frequency model of interval timing as it pertains to cannabinoid signaling and propose a neurocircuitry through which this system modulates interoceptive time cues.

  3. Signaling mechanism underlying the histamine-modulated action of hypoglossal motoneurons.

    Science.gov (United States)

    Liu, Zi-Long; Wu, Xu; Luo, Yan-Jia; Wang, Lu; Qu, Wei-Min; Li, Shan-Qun; Huang, Zhi-Li

    2016-04-01

    Histamine, an important modulator of the arousal states of the central nervous system, has been reported to contribute an excitatory drive at the hypoglossal motor nucleus to the genioglossus (GG) muscle, which is involved in the pathogenesis of obstructive sleep apnea. However, the effect of histamine on hypoglossal motoneurons (HMNs) and the underlying signaling mechanisms have remained elusive. Here, whole-cell patch-clamp recordings were conducted using neonatal rat brain sections, which showed that histamine excited HMNs with an inward current under voltage-clamp and a depolarization membrane potential under current-clamp via histamine H1 receptors (H1Rs). The phospholipase C inhibitor U-73122 blocked H1Rs-mediated excitatory effects, but protein kinase A inhibitor and protein kinase C inhibitor did not, indicating that the signal transduction cascades underlying the excitatory action of histamine on HMNs were H1R/Gq/11 /phospholipase C/inositol-1,4,5-trisphosphate (IP3). The effects of histamine were also dependent on extracellular Na(+) and intracellular Ca(2+), which took place via activation of Na(+)-Ca(2+) exchangers. These results identify the signaling molecules associated with the regulatory effect of histamine on HMNs. The findings of this study may provide new insights into therapeutic approaches in obstructive sleep apnea. We proposed the post-synaptic mechanisms underlying the modulation effect of histamine on hypoglossal motoneuron. Histamine activates the H1Rs via PLC and IP3, increases Ca(2+) releases from intracellular stores, promotes Na(+) influx and Ca(2+) efflux via the NCXs, and then produces an inward current and depolarizes the neurons. Histamine modulates the excitability of HMNs with other neuromodulators, such as noradrenaline, serotonin and orexin. We think that these findings should provide an important new direction for drug development for the treatment of obstructive sleep apnea.

  4. Endocannabinoid-dependent modulation of phasic dopamine signaling encodes external and internal reward-predictive cues

    Directory of Open Access Journals (Sweden)

    Jennifer M. Wenzel

    2014-09-01

    Full Text Available The mesolimbic dopamine (DA system plays an integral role in incentive motivation and reward seeking and a growing body of evidence identifies signal transduction at cannabinoid receptors as a critical modulator of this system. Indeed, administration of exogenous cannabinoids results in burst firing of DA neurons of the ventral tegmental area and increases extracellular DA in the nucleus accumbens (NAcc. Implementation of fast-scan cyclic voltammetry (FSCV confirms the ability of cannabinoids to augment DA within the NAcc on a subsecond timescale. The use of FSCV along with newly developed highly selective pharmacological compounds advances our understanding of how cannabinoids influence DA transmission, and highlights a role for endocannabinoid-modulated subsecond DAergic activation in the incentive motivational properties of not only external, but also internal reward-predictive cues. For example, our laboratory has recently demonstrated that in mice responding under a fixed interval (FI schedule for food reinforcement, fluctuations in NAcc DA signal the principal cue predictive of reinforcer availability – time. That is, as the interval progresses, NAcc DA levels decline leading to accelerated food seeking and the resulting characteristic FI scallop pattern of responding. Importantly, administration of WIN 55,212-2, a synthetic cannabinoid agonist, or JZL184, an indirect cannabinoid agonist, increase DA levels during the interval and disrupt this pattern of responding. Along with a wealth of other reports, these results illustrate the role of cannabinoid receptor activation in the regulation of DA transmission and the control of temporally guided reward seeking. The current review will explore the striatal beat frequency model of interval timing as it pertains cannabinoid signaling and propose a neurocircuitry through which this system modulates interoceptive time cues.

  5. Behaviors of harmonic signals in wavelength-modulated spectroscopy under high absorption strength

    Institute of Scientific and Technical Information of China (English)

    Yuntao Wang; Haiwen Cai; Jianxin Geng; Zhengqing Pan; Dijun Chen; Zujie Fang

    2007-01-01

    @@ Behaviors of harmonic signals in wavelength modulation spectroscopy (WMS) for gas detection with Lorentzian line under high absorption strength are investigated. Approximate analytic expressions of the second, fourth, and sixth harmonics on the strength are presented in concise forms. Simulations show that the expressions are in agreement with the Fourier expansion by numerical integration. It is expected theoretically and experimentally in a WMS system for methane detection that there are not only a maximum, but also a null point in the harmonics versus strength relations, which should be of practical importance in methane sensing applications.

  6. Electroabsorption modulators used for all-optical signal processing and labelling

    DEFF Research Database (Denmark)

    Xu, Lin

    2004-01-01

    -optical demultiplexing experiment from 160 Gb/s to 10 Gb/s using a single EAM with a very simple waveguide structure is presented. All 16 demultiplexed tributary channels are error free with an average receiver sensitivity of –25.3 dBm. An improvement of up to 6 dB in the receiver sensitivity by regeneration...... impacts on the extinction ratio, average power and pulse width of the wavelength-converted signal. Other wavelength conversion schemes such as fibre-based cross phase modulation (XPM) and optical filtering, fibre-based Kerr switch, fibre based four-wave-mixing (FWM) and semiconductor optical amplifier...

  7. Comparison of digital signal processing modules in gamma-ray spectrometry.

    Science.gov (United States)

    Lépy, Marie-Christine; Cissé, Ousmane Ibrahima; Pierre, Sylvie

    2014-05-01

    Commercial digital signal-processing modules have been tested for their applicability to gamma-ray spectrometry. The tests were based on the same n-type high purity germanium detector. The spectrum quality was studied in terms of energy resolution and peak area versus shaping parameters, using a Eu-152 point source. The stability of a reference peak count rate versus the total count rate was also examined. The reliability of the quantitative results is discussed for their use in measurement at the metrological level.

  8. Stochastic resonance in a fractional harmonic oscillator subject to random mass and signal-modulated noise

    Science.gov (United States)

    Guo, Feng; Zhu, Cheng-Yin; Cheng, Xiao-Feng; Li, Heng

    2016-10-01

    Stochastic resonance in a fractional harmonic oscillator with random mass and signal-modulated noise is investigated. Applying linear system theory and the characteristics of the noises, the analysis expression of the mean output-amplitude-gain (OAG) is obtained. It is shown that the OAG varies non-monotonically with the increase of the intensity of the multiplicative dichotomous noise, with the increase of the frequency of the driving force, as well as with the increase of the system frequency. In addition, the OAG is a non-monotonic function of the system friction coefficient, as a function of the viscous damping coefficient, as a function of the fractional exponent.

  9. Coherent-detection-assisted BOTDA system without averaging using single-sideband modulated local oscillator signal

    Science.gov (United States)

    Guo, Nan; Wang, Liang; Jin, Chao; Gui, Tao; Zhong, Kangping; Zhou, Xian; Yuan, Jinhui; Yu, Changyuan; Tam, Hwa-Yaw; Lu, Chao

    2017-04-01

    A novel setup for coherent-detection-assisted Brillouin optical time domain analysis (BOTDA) is proposed and demonstrated. Performance enhancement is enabled by a power-controllable local oscillator (LO) generated using single-side-band (SSB) modulation. Through employing a commercial coherent receiver and polarization diversity scheme, the Brillouin gain traces carried on a stable intermediate frequency (IF) are obtained in real time without any averaging and processed by digital signal processing (DSP) without the need of ultra-narrow optical band pass filter. A spatial resolution of 4 m and frequency uncertainty of 1.473 MHz are achieved over 40 km sensing range using a single scan.

  10. Modulation of Innate Immune Signalling by Lipid-Mediated MAVS Transmembrane Domain Oligomerization.

    Directory of Open Access Journals (Sweden)

    Luis Nobre

    Full Text Available RIG-I-like receptors detect viral RNA in infected cells and promote oligomerization of the outer mitochondrial membrane protein MAVS to induce innate immunity to viral infection through type I interferon production. Mitochondrial reactive oxygen species (mROS have been shown to enhance anti-viral MAVS signalling, but the mechanisms have remained obscure. Using a biochemical oligomerization-reporter fused to the transmembrane domain of MAVS, we found that mROS inducers promoted lipid-dependent MAVS transmembrane domain oligomerization in the plane of the outer mitochondrial membrane. These events were mirrored by Sendai virus infection, which similarly induced lipid peroxidation and promoted lipid-dependent MAVS transmembrane domain oligomerization. Our observations point to a role for mROS-induced changes in lipid bilayer properties in modulating antiviral innate signalling by favouring the oligomerization of MAVS transmembrane domain in the outer-mitochondrial membrane.

  11. Experiments of Multi-Level Read-Only Recording Using Readout Signal Wave-Shape Modulation

    Institute of Scientific and Technical Information of China (English)

    TANG Yi; PEI Jing; PAN Long-Fa; NI Yi; HU Hua; ZHANG Bu-Qing

    2008-01-01

    An innovative multilevel read-only recording method is proposed.In this method,a short pit/land is deliberately inserted to the original land/pit.This modifies the wave-shape of readout signal.Taking the wave-shape as the symbol of level detection,a signal wave-shape modulation (SWSM) multilevel method is realized.This method is carried out and validated on the DVD read-only manufacture and readout system.A capacity of 15 GB can be expected,and a bit error rate of 10-4 is achieved.The capacity can meet the demand of high definition movie publication.This method also provides a potential multi-level solution for other storage formats and systems.

  12. The social modulation of pain: Others as predictive signals of salience – A systematic review

    Directory of Open Access Journals (Sweden)

    Charlotte eKrahé

    2013-07-01

    Full Text Available Several studies in cognitive neuroscience have investigated the cognitive and affective modulation of pain. By contrast, fewer studies have focused on the social modulation of pain, despite a plethora of relevant clinical findings. Here we present the first review of experimental studies addressing how interpersonal factors, such as the presence, behaviour and spatial proximity of an observer, modulate pain. Based on a systematic literature search we identified twenty-six studies on experimentally-induced pain that manipulated different interpersonal variables and measured behavioural, physiological and neural pain-related responses. We observed that the modulation of pain by interpersonal factors depended on (1 the degree to which the social partners were active or were perceived by the participants to possess possibility for action; (2 the degree to which participants could perceive the specific intentions of the social partners; (3 the type of pre-existing relationship between the social partner and the person in pain, and lastly, (4 individual differences in relating to others and coping styles. Based on these findings, we propose that the modulation of pain by social factors can be fruitfully understood in relation to a recent predictive coding model, the free energy framework, particularly as applied to interoception and social cognition. Specifically, we argue that interpersonal interactions during pain may function as social, predictive signals of contextual threat or safety and as such influence the salience of noxious stimuli. The perception of such interpersonal interactions may in turn depend on (a prior beliefs about interpersonal relating and (b the certainty or precision by which an interpersonal interaction may predict environmental threat or safety.

  13. Communicative Signals Promote Object Recognition Memory and Modulate the Right Posterior STS.

    Science.gov (United States)

    Redcay, Elizabeth; Ludlum, Ruth S; Velnoskey, Kayla R; Kanwal, Simren

    2016-01-01

    Detection of communicative signals is thought to facilitate knowledge acquisition early in life, but less is known about the role these signals play in adult learning or about the brain systems supporting sensitivity to communicative intent. The current study examined how ostensive gaze cues and communicative actions affect adult recognition memory and modulate neural activity as measured by fMRI. For both the behavioral and fMRI experiments, participants viewed a series of videos of an actress acting on one of two objects in front of her. Communicative context in the videos was manipulated in a 2 × 2 design in which the actress either had direct gaze (Gaze) or wore a visor (NoGaze) and either pointed at (Point) or reached for (Reach) one of the objects (target) in front of her. Participants then completed a recognition memory task with old (target and nontarget) objects and novel objects. Recognition memory for target objects in the Gaze conditions was greater than NoGaze, but no effects of gesture type were seen. Similarly, the fMRI video-viewing task revealed a significant effect of Gaze within right posterior STS (pSTS), but no significant effects of Gesture. Furthermore, pSTS sensitivity to Gaze conditions was related to greater memory for objects viewed in Gaze, as compared with NoGaze, conditions. Taken together, these results demonstrate that the ostensive, communicative signal of direct gaze preceding an object-directed action enhances recognition memory for attended items and modulates the pSTS response to object-directed actions. Thus, establishment of a communicative context through ostensive signals remains an important component of learning and memory into adulthood, and the pSTS may play a role in facilitating this type of social learning.

  14. Dopamine-sensitive signaling mediators modulate psychostimulant-induced ultrasonic vocalization behavior in rats.

    Science.gov (United States)

    Williams, Stacey N; Undieh, Ashiwel S

    2016-01-01

    The mesolimbic dopamine system plays a major role in psychostimulant-induced ultrasonic vocalization (USV) behavior in rodents. Within this system, psychostimulants elevate synaptic concentrations of dopamine thereby leading to exaggerated activation of postsynaptic dopamine receptors within the D1-like and D2-like subfamilies. Dopamine receptor stimulation activate several transmembrane signaling systems and cognate intracellular mediators; downstream activation of transcription factors then conveys the information from receptor activation to appropriate modulation of cellular and physiologic functions. We previously showed that cocaine-induced USV behavior was associated with enhanced expression of the neurotrophin BDNF. Like cocaine, amphetamine also increases synaptic dopamine levels, albeit primarily through facilitating dopamine release. Therefore, in the present study we investigated whether amphetamine and cocaine similarly activate dopamine-linked signaling cascades to regulate intracellular mediators leading to induction of USV behavior. The results show that amphetamine increased the emission of 50 kHz USVs and this effect was blocked by SCH23390, a D1 receptor antagonist. Similar to cocaine, amphetamine increased BDNF protein expression in discrete brain regions, while pretreatment with K252a, a trkB neurotrophin receptor inhibitor, significantly reduced amphetamine-induced USV behavior. Inhibition of cyclic-AMP/PKA signaling with H89 or inhibition of PLC signaling with U73122 significantly blocked both the acute and subchronic amphetamine-induced USV behavior. In contrast, pharmacologic inhibition of either pathway enhanced cocaine-induced USV behavior. Although cocaine and amphetamine similarly modulate neurotrophin expression and USV, the molecular mechanisms by which these psychostimulants differentially activate dopamine receptor subtypes or other monoaminergic systems may be responsible for the distinct aspects of behavioral responses.

  15. Rho signaling in Entamoeba histolytica modulates actomyosin-dependent activities stimulated during invasive behavior.

    Science.gov (United States)

    Franco-Barraza, Janusz; Zamudio-Meza, Horacio; Franco, Elizabeth; del Carmen Domínguez-Robles, M; Villegas-Sepúlveda, Nicolás; Meza, Isaura

    2006-03-01

    Interaction of Entamoeba histolytica trophozoites with target cells and substrates activates signaling pathways in the parasite. Phosphorylation cascades triggered by phospho-inositide and adenyl-cyclase-dependent pathways modulate reorganization of the actin cytoskeleton to form structures that facilitate adhesion. In contrast, little is known about participation of Rho proteins and Rho signaling in actin rearrangements. We report here the in vivo expression of at least one Rho protein in trophozoites, whose activation induced actin reorganization and actin-myosin interaction. Antibodies to EhRhoA1 recombinant protein mainly localized Rho in the cytosol of nonactivated amoebae, but it was translocated to vesicular membranes and to some extent to the plasma membrane after treatment with lysophosphatidic acid (LPA), a specific agonist of Rho activation. Activated Rho was identified in LPA-treated trophozoites. LPA induced striking polymerization of actin into distinct dynamic structures. Disorganization of these structures by inhibition of Rho effector, Rho-kinase (ROCK), and by ML-7, an inhibitor of myosin light chain kinase dependent phosphorylation of myosin light chain, suggested that the actin structures also contained myosin. LPA stimulated concanavalin-A-mediated formation of caps, chemotaxis, invasion of extracellular matrix substrates, and erythrophagocytosis, but not binding to fibronectin. ROCK inhibition impaired LPA-stimulated functions and to some extent adhesion to fibronectin. Similar results were obtained with ML-7. These data suggest the presence and operation of Rho-signaling pathways in E. histolytica, that together with other, already described, signaling routes modulate actomyosin-dependent motile processes, particularly stimulated during invasive behavior.

  16. Modulation of Cell Signaling Networks after CTLA4 Blockade in Patients with Metastatic Melanoma

    Science.gov (United States)

    Comin-Anduix, Begoña; Sazegar, Hooman; Chodon, Thinle; Matsunaga, Douglas; Jalil, Jason; von Euw, Erika; Escuin-Ordinas, Helena; Balderas, Robert; Chmielowski, Bartosz; Gomez-Navarro, Jesus; Koya, Richard C.; Ribas, Antoni

    2010-01-01

    Background The effects on cell signalling networks upon blockade of cytotoxic T lymphocyte-associated antigen-4 (CTLA4) using the monoclonal antibody tremelimumab were studied in peripheral blood mononuclear cell (PBMC) samples from patients with metastatic melanoma. Methodology/Principal Findings Intracellular flow cytometry was used to detect phosphorylated (p) signaling molecules downstream of the T cell receptor (TCR) and cytokine receptors. PBMC from tremelimumab-treated patients were characterized by increase in pp38, pSTAT1 and pSTAT3, and decrease in pLck, pERK1/2 and pSTAT5 levels. These changes were noted in CD4 and CD8 T lymphocytes but also in CD14 monocytes. A divergent pattern of phosphorylation of Zap70, LAT, Akt and STAT6 was noted in patients with or without an objective tumor response. Conclusions/Significance The administration of the CTLA4-blocking antibody tremelimumab to patients with metastatic melanoma influences signaling networks downstream of the TCR and cytokine receptors both in T cells and monocytes. The strong modulation of signaling networks in monocytes suggests that this cell subset may be involved in clinical responses to CTLA4 blockade. Clinical Trial Registration clinicaltrials.gov; Registration numbers NCT00090896 and NCT00471887 PMID:20856802

  17. Modulation of cell signaling networks after CTLA4 blockade in patients with metastatic melanoma.

    Directory of Open Access Journals (Sweden)

    Begoña Comin-Anduix

    Full Text Available BACKGROUND: The effects on cell signalling networks upon blockade of cytotoxic T lymphocyte-associated antigen-4 (CTLA4 using the monoclonal antibody tremelimumab were studied in peripheral blood mononuclear cell (PBMC samples from patients with metastatic melanoma. METHODOLOGY/PRINCIPAL: Findings Intracellular flow cytometry was used to detect phosphorylated (p signaling molecules downstream of the T cell receptor (TCR and cytokine receptors. PBMC from tremelimumab-treated patients were characterized by increase in pp38, pSTAT1 and pSTAT3, and decrease in pLck, pERK1/2 and pSTAT5 levels. These changes were noted in CD4 and CD8 T lymphocytes but also in CD14 monocytes. A divergent pattern of phosphorylation of Zap70, LAT, Akt and STAT6 was noted in patients with or without an objective tumor response. CONCLUSIONS/SIGNIFICANCE: The administration of the CTLA4-blocking antibody tremelimumab to patients with metastatic melanoma influences signaling networks downstream of the TCR and cytokine receptors both in T cells and monocytes. The strong modulation of signaling networks in monocytes suggests that this cell subset may be involved in clinical responses to CTLA4 blockade. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov; Registration numbers NCT00090896 and NCT00471887.

  18. Modulating P2X7 Receptor Signaling during Rheumatoid Arthritis: New Therapeutic Approaches for Bisphosphonates

    Directory of Open Access Journals (Sweden)

    Alberto Baroja-Mazo

    2012-01-01

    Full Text Available P2X7 receptor-mediated purinergic signaling is a well-known mechanism involved in bone remodeling. The P2X7 receptor has been implicated in the pathophysiology of various bone and cartilage diseases, including rheumatoid arthritis (RA, a widespread and complex chronic inflammatory disorder. The P2X7 receptor induces the release into the synovial fluid of the proinflammatory factors (e.g., interleukin-1β, prostaglandins, and proteases responsible for the clinical symptoms of RA. Thus, the P2X7 receptor is emerging as a novel anti-inflammatory therapeutic target, and various selective P2X7 receptor antagonists are under clinical trials. Extracellular ATP signaling acting through the P2X7 receptor is a complex and dynamic scenario, which varies over the course of inflammation. This signaling is partially modulated by the activity of ectonucleotidases, which degrade extracellular ATP to generate other active molecules such as adenosine or pyrophosphates. Recent evidence suggests differential extracellular metabolism of ATP during the resolution of inflammation to generate pyrophosphates. Extracellular pyrophosphate dampens proinflammatory signaling by promoting alternative macrophage activation. Our paper shows that bisphosphonates are metabolically stable pyrophosphate analogues that are able to mimic the anti-inflammatory function of pyrophosphates. Bisphosphonates are arising per se as promising anti-inflammatory drugs to treat RA, and this therapy could be improved when administrated in combination with P2X7 receptor antagonists.

  19. A cyclic GMP signalling module that regulates gliding motility in a malaria parasite.

    Directory of Open Access Journals (Sweden)

    Robert W Moon

    2009-09-01

    Full Text Available The ookinete is a motile stage in the malaria life cycle which forms in the mosquito blood meal from the zygote. Ookinetes use an acto-myosin motor to glide towards and penetrate the midgut wall to establish infection in the vector. The regulation of gliding motility is poorly understood. Through genetic interaction studies we here describe a signalling module that identifies guanosine 3', 5'-cyclic monophosphate (cGMP as an important second messenger regulating ookinete differentiation and motility. In ookinetes lacking the cyclic nucleotide degrading phosphodiesterase delta (PDEdelta, unregulated signalling through cGMP results in rounding up of the normally banana-shaped cells. This phenotype is suppressed in a double mutant additionally lacking guanylyl cyclase beta (GCbeta, showing that in ookinetes GCbeta is an important source for cGMP, and that PDEdelta is the relevant cGMP degrading enzyme. Inhibition of the cGMP-dependent protein kinase, PKG, blocks gliding, whereas enhanced signalling through cGMP restores normal gliding speed in a mutant lacking calcium dependent protein kinase 3, suggesting at least a partial overlap between calcium and cGMP dependent pathways. These data demonstrate an important function for signalling through cGMP, and most likely PKG, in dynamically regulating ookinete gliding during the transmission of malaria to the mosquito.

  20. Insulin-FOXO3 signaling modulates circadian rhythms via regulation of clock transcription.

    Science.gov (United States)

    Chaves, Inês; van der Horst, Gijsbertus T J; Schellevis, Raymond; Nijman, Romana M; Koerkamp, Marian Groot; Holstege, Frank C P; Smidt, Marten P; Hoekman, Marco F M

    2014-06-02

    Circadian rhythms are responsive to external and internal cues, light and metabolism being among the most important. In mammals, the light signal is sensed by the retina and transmitted to the suprachiasmatic nucleus (SCN) master clock [1], where it is integrated into the molecular oscillator via regulation of clock gene transcription. The SCN synchronizes peripheral oscillators, an effect that can be overruled by incoming metabolic signals [2]. As a consequence, peripheral oscillators can be uncoupled from the master clock when light and metabolic signals are not in phase. The signaling pathways responsible for coupling metabolic cues to the molecular clock are being rapidly uncovered [3-5]. Here we show that insulin-phosphatidylinositol 3-kinase (PI3K)-Forkhead box class O3 (FOXO3) signaling is required for circadian rhythmicity in the liver via regulation of Clock. Knockdown of FoxO3 dampens circadian amplitude, an effect that is rescued by overexpression of Clock. Subsequently, we show binding of FOXO3 to two Daf-binding elements (DBEs) located in the Clock promoter area, implicating Clock as a transcriptional target of FOXO3. Transcriptional oscillation of both core clock and output genes in the liver of FOXO3-deficient mice is affected, indicating a disrupted hepatic circadian rhythmicity. Finally, we show that insulin, a major regulator of FOXO activity [6-9], regulates Clock levels in a PI3K- and FOXO3-dependent manner. Our data point to a key role of the insulin-FOXO3-Clock signaling pathway in the modulation of circadian rhythms.

  1. Emission properties of Tb{sup 3+} ions in LYSO: evidence of a cross relaxation mechanism explained by a kinetic model

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, P C; Salis, M; Corpino, R; Carbonaro, C M; Anedda, A [Dipartimento di Fisica, Universita di Cagliari, Cittadella Universitaria, S.P. No. 8, I-09042 Monserrato (Cagliari) (Italy); Fortin, E, E-mail: carlo.ricci@dsf.unica.i [Department of Physics, Macdonald Hall, 150 Louis Pasteur, Ottawa, ON, K1N 6N5 (Canada)

    2010-09-01

    The optical properties of Tb{sup 3+} ions in oxyorthosilicates of lutetium and yttrium (LYSO) are reported. The introduction of a small number of terbium ions (nominal content 10 ppm) generates, in the otherwise transparent absorption spectrum of the matrix, an ultraviolet absorption band peaked at about 240 nm. By exciting within the reported UV band, line shaped emissions in the 350-600 nm range are detected. These transitions are related to the {sup 5}D{sub 3} and {sup 5}D{sub 4} levels of the Tb{sup 3+} ions and are characterized by decay times in the millisecond time domain. Analysis of the decay time measurements allows us to individuate a cross relaxation mechanism among terbium ions even at the low dopant concentration investigated. We propose a three-level kinetic model which is able to successfully reproduce the experimental data, allowing us to discriminate among the radiative and non-radiative contributions to the observed emissions.

  2. The NF-YC–RGL2 module integrates GA and ABA signalling to regulate seed germination in Arabidopsis

    Science.gov (United States)

    Liu, Xu; Hu, Pengwei; Huang, Mingkun; Tang, Yang; Li, Yuge; Li, Ling; Hou, Xingliang

    2016-01-01

    The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in the modulation of seed germination. However, the molecular mechanism of such phytohormone interaction remains largely elusive. Here we show that three Arabidopsis NUCLEAR FACTOR-Y C (NF-YC) homologues NF-YC3, NF-YC4 and NF-YC9 redundantly modulate GA- and ABA-mediated seed germination. These NF-YCs interact with the DELLA protein RGL2, a key repressor of GA signalling. The NF-YC–RGL2 module targets ABI5, a gene encoding a core component of ABA signalling, via specific CCAAT elements and collectively regulates a set of GA- and ABA-responsive genes, thus controlling germination. These results suggest that the NF-YC–RGL2–ABI5 module integrates GA and ABA signalling pathways during seed germination. PMID:27624486

  3. Temperature-induced protein secretion by Leishmania mexicana modulates macrophage signalling and function.

    Science.gov (United States)

    Hassani, Kasra; Antoniak, Elisabeth; Jardim, Armando; Olivier, Martin

    2011-05-03

    Protozoan parasites of genus Leishmania are the causative agents of leishmaniasis. These digenetic microorganisms undergo a marked environmental temperature shift (TS) during transmission from the sandfly vector (ambient temperature, 25-26°C) to the mammalian host (37°C). We have observed that this TS induces a rapid and dramatic increase in protein release from Leishmania mexicana (cutaneous leishmaniasis) within 4 h. Proteomic identification of the TS-induced secreted proteins revealed 72 proteins, the majority of which lack a signal peptide and are thus thought to be secreted via nonconventional mechanisms. Interestingly, this protein release is accompanied by alterations in parasite morphology including an augmentation in the budding of exovesicles from its surface. Here we show that the exoproteome of L. mexicana upon TS induces cleavage and activation of the host protein tyrosine phosphatases, specifically SHP-1 and PTP1-B, in a murine bone-marrow-derived macrophage cell line. Furthermore, translocation of prominent inflammatory transcription factors, namely NF-κB and AP-1 is altered. The exoproteome also caused inhibition of nitric oxide production, a crucial leishmanicidal function of the macrophage. Overall, our results provide strong evidence that within early moments of interaction with the mammalian host, L. mexicana rapidly releases proteins and exovesicles that modulate signalling and function of the macrophage. These modulations can result in attenuation of the inflammatory response and deactivation of the macrophage aiding the parasite in the establishment of infection.

  4. Temperature-induced protein secretion by Leishmania mexicana modulates macrophage signalling and function.

    Directory of Open Access Journals (Sweden)

    Kasra Hassani

    Full Text Available Protozoan parasites of genus Leishmania are the causative agents of leishmaniasis. These digenetic microorganisms undergo a marked environmental temperature shift (TS during transmission from the sandfly vector (ambient temperature, 25-26°C to the mammalian host (37°C. We have observed that this TS induces a rapid and dramatic increase in protein release from Leishmania mexicana (cutaneous leishmaniasis within 4 h. Proteomic identification of the TS-induced secreted proteins revealed 72 proteins, the majority of which lack a signal peptide and are thus thought to be secreted via nonconventional mechanisms. Interestingly, this protein release is accompanied by alterations in parasite morphology including an augmentation in the budding of exovesicles from its surface. Here we show that the exoproteome of L. mexicana upon TS induces cleavage and activation of the host protein tyrosine phosphatases, specifically SHP-1 and PTP1-B, in a murine bone-marrow-derived macrophage cell line. Furthermore, translocation of prominent inflammatory transcription factors, namely NF-κB and AP-1 is altered. The exoproteome also caused inhibition of nitric oxide production, a crucial leishmanicidal function of the macrophage. Overall, our results provide strong evidence that within early moments of interaction with the mammalian host, L. mexicana rapidly releases proteins and exovesicles that modulate signalling and function of the macrophage. These modulations can result in attenuation of the inflammatory response and deactivation of the macrophage aiding the parasite in the establishment of infection.

  5. Algorithm for the classification of multi-modulating signals on the electrocardiogram.

    Science.gov (United States)

    Mita, Mitsuo

    2007-03-01

    This article discusses the algorithm to measure electrocardiogram (ECG) and respiration simultaneously and to have the diagnostic potentiality for sleep apnoea from ECG recordings. The algorithm is composed by the combination with the three particular scale transform of a(j)(t), u(j)(t), o(j)(a(j)) and the statistical Fourier transform (SFT). Time and magnitude scale transforms of a(j)(t), u(j)(t) change the source into the periodic signal and tau(j) = o(j)(a(j)) confines its harmonics into a few instantaneous components at tau(j) being a common instant on two scales between t and tau(j). As a result, the multi-modulating source is decomposed by the SFT and is reconstructed into ECG, respiration and the other signals by inverse transform. The algorithm is expected to get the partial ventilation and the heart rate variability from scale transforms among a(j)(t), a(j+1)(t) and u(j+1)(t) joining with each modulation. The algorithm has a high potentiality of the clinical checkup for the diagnosis of sleep apnoea from ECG recordings.

  6. Nicotinic modulation of hippocampal cell signaling and associated effects on learning and memory.

    Science.gov (United States)

    Kutlu, Munir Gunes; Gould, Thomas J

    2016-03-01

    The hippocampus is a key brain structure involved in synaptic plasticity associated with long-term declarative memory formation. Importantly, nicotine and activation of nicotinic acetylcholine receptors (nAChRs) can alter hippocampal plasticity and these changes may occur through modulation of hippocampal kinases and transcription factors. Hippocampal kinases such as cAMP-dependent protein kinase (PKA), calcium/calmodulin-dependent protein kinases (CAMKs), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and c-jun N-terminal kinase 1 (JNK1), and the transcription factor cAMP-response element-binding protein (CREB) that are activated either directly or indirectly by nicotine may modulate hippocampal plasticity and in parallel hippocampus-dependent learning and memory. Evidence suggests that nicotine may alter hippocampus-dependent learning by changing the time and magnitude of activation of kinases and transcription factors normally involved in learning and by recruiting additional cell signaling molecules. Understanding how nicotine alters learning and memory will advance basic understanding of the neural substrates of learning and aid in understanding mental disorders that involve cognitive and learning deficits.

  7. C. elegans ADAMTS ADT-2 regulates body size by modulating TGFβ signaling and cuticle collagen organization

    Science.gov (United States)

    Fernando, Thilini; Flibotte, Stephane; Xiong, Sheng; Yin, Jianghua; Yzeiraj, Edlira; Moerman, Donald G.; Meléndez, Alicia; Savage-Dunn, Cathy

    2011-01-01

    Organismal growth and body size are influenced by both genetic and environmental factors. We have utilized the strong molecular genetic techniques available in the nematode C. elegans to identify genetic determinants of body size. In C. elegans, DBL-1, a member of the conserved family of secreted growth factors known as the Transforming Growth Factor β superfamily, is known to play a major role in growth control. The mechanisms by which other determinants of body size function, however, is less well understood. To identify additional genes involved in body size regulation, a genetic screen for small mutants was previously performed. One of the genes identified in that screen was sma-21. We now demonstrate that sma-21 encodes ADT-2, a member of the ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family of secreted metalloproteases. ADAMTS proteins are believed to remodel the extracellular matrix and may modulate the activity of extracellular signals. Genetic interactions suggest that ADT-2 acts in parallel with or in multiple size regulatory pathways. We demonstrate that ADT-2 is required for normal levels of expression of a DBL-1-responsive transcriptional reporter. We further demonstrate that adt-2 regulatory sequences drive expression in glial-like and vulval cells, and that ADT-2 activity is required for normal cuticle collagen fibril organization. We therefore propose that ADT-2 regulates body size both by modulating TGFβ signaling activity and by maintaining normal cuticle structure. PMID:21256840

  8. Slit/Robo signaling modulates the proliferation of central nervous system progenitors.

    Science.gov (United States)

    Borrell, Víctor; Cárdenas, Adrián; Ciceri, Gabriele; Galcerán, Joan; Flames, Nuria; Pla, Ramón; Nóbrega-Pereira, Sandrina; García-Frigola, Cristina; Peregrín, Sandra; Zhao, Zhen; Ma, Le; Tessier-Lavigne, Marc; Marín, Oscar

    2012-10-18

    Neurogenesis relies on a delicate balance between progenitor maintenance and neuronal production. Progenitors divide symmetrically to increase the pool of dividing cells. Subsequently, they divide asymmetrically to self-renew and produce new neurons or, in some brain regions, intermediate progenitor cells (IPCs). Here we report that central nervous system progenitors express Robo1 and Robo2, receptors for Slit proteins that regulate axon guidance, and that absence of these receptors or their ligands leads to loss of ventricular mitoses. Conversely, production of IPCs is enhanced in Robo1/2 and Slit1/2 mutants, suggesting that Slit/Robo signaling modulates the transition between primary and intermediate progenitors. Unexpectedly, these defects do not lead to transient overproduction of neurons, probably because supernumerary IPCs fail to detach from the ventricular lining and cycle very slowly. At the molecular level, the role of Slit/Robo in progenitor cells involves transcriptional activation of the Notch effector Hes1. These findings demonstrate that Robo signaling modulates progenitor cell dynamics in the developing brain.

  9. Endocannabinoids modulate cortical development by configuring Slit2/Robo1 signalling.

    Science.gov (United States)

    Alpár, Alán; Tortoriello, Giuseppe; Calvigioni, Daniela; Niphakis, Micah J; Milenkovic, Ivan; Bakker, Joanne; Cameron, Gary A; Hanics, János; Morris, Claudia V; Fuzik, János; Kovacs, Gabor G; Cravatt, Benjamin F; Parnavelas, John G; Andrews, William D; Hurd, Yasmin L; Keimpema, Erik; Harkany, Tibor

    2014-07-17

    Local environmental cues are indispensable for axonal growth and guidance during brain circuit formation. Here, we combine genetic and pharmacological tools, as well as systems neuroanatomy in human fetuses and mouse models, to study the role of endocannabinoid and Slit/Robo signalling in axonal growth. We show that excess 2-arachidonoylglycerol, an endocannabinoid affecting directional axonal growth, triggers corpus callosum enlargement due to the errant CB1 cannabinoid receptor-containing corticofugal axon spreading. This phenotype mechanistically relies on the premature differentiation and end-feet proliferation of CB2R-expressing oligodendrocytes. We further show the dependence of both axonal Robo1 positioning and oligodendroglial Slit2 production on cell-type-specific cannabinoid receptor activation. Accordingly, Robo1 and/or Slit2 manipulation limits endocannabinoid modulation of axon guidance. We conclude that endocannabinoids can configure focal Slit2/Robo1 signalling to modulate directional axonal growth, which may provide a basis for understanding impaired brain wiring associated with metabolic deficits and prenatal drug exposure.

  10. A WDM-PON with DPSK modulated downstream and OOK modulated upstream signals based on symmetric 10 Gbit/s wavelength reused bidirectional reflective SOA

    Science.gov (United States)

    El-Nahal, Fady I.

    2017-01-01

    We investigate a wavelength-division-multiplexing passive optical network (WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying (DPSK) downstream signals and on-off keying (OOK) upstream signals, respectively. A wavelength reused scheme is employed to carry the upstream data by using a reflective semiconductor optical amplifier (RSOA) as an intensity modulator at the optical network unit (ONU). The constant-intensity property of the DPSK modulation format can keep high extinction ratio ( ER) of downstream signal and reduce the crosstalk to the upstream signal. The bit error rate ( BER) performance of our scheme shows that the proposed 10 Gbit/s symmetric WDM-PON can achieve error free transmission over 25-km-long fiber transmission with low power penalty.

  11. Noise figure of microwave photonic links operating under large-signal modulation and its application to optoelectronic oscillators.

    Science.gov (United States)

    Hosseini, Seyyed Esmail; Banai, Ali

    2014-10-01

    The noise performance of intensity-modulation direct-detection microwave photonic links (MWPL) operating under large-signal conditions has been studied in this paper. A sinusoidal signal plus narrowband white Gaussian noise is applied at the radio frequency input of the link, and the output spectrum is derived using a nonlinear analytical approach. We show that the output SNR can be severely affected by the interaction of signal and noise due to the nonlinearity of the MWPL combined with the large input modulating signal. It is shown that the large-signal noise figure (NF) of an MWPL depends on the input power, a dependence that is not readily apparent under small-signal conditions, due to two unavoidable issues appearing in the large-signal conditions: (1) the link power gain is a function of its input power, and (2) the link power gain is not the same for the signal and noise due to the capture effect. We also have observed that if shot noise or laser relative intensity noise (RIN) is the dominant source of noise, link large-signal NF increases as the input signal power increases. We have shown that, when the MWPL is operating in the linear regime, our theoretical predictions approach the already published results on small-signal NF, which are verified by experimental data. We have shown that large-signal NF affects the noise performance of optoelectronic oscillators because they contain MWPLs at saturation.

  12. Modulating neurotoxicity through CX3CL1/CX3CR1 signaling

    Directory of Open Access Journals (Sweden)

    Cristina eLimatola

    2014-08-01

    Full Text Available Since the initial cloning of fractalkine/CX3CL1, it was proposed that the only known member of the CX3C or delta subfamily of chemotactic cytokines could play some significant role in the nervous system, due to its high expression on neurons. The pivotal description of the localization of the unique CX3CL1 receptor, CX3CR1, on microglial cells, firmed up by the generation of cx3cr1GFP/GFP mice, opened the road to the hypothesis of some specific key interactions between microglia and neurons mediated by this pair. This expectation has been indeed supported by recent exciting evidence indicating that CX3CL1-mediated microglia-neuron interaction modulates basic physiological activities during development, adulthood and aging, including: synaptic pruning; promoting survival of neurons and neural precursors; modulating synaptic transmission and plasticity; enhancing synapse and network maturation; and facilitating the establishment of neuropathic pain circuits. Beyond playing such fascinating roles in physiological conditions, CX3CL1 signaling has been implicated in different neuropathologies. Early papers demonstrated that the levels of CX3CL1 may be modulated by various toxic stimuli in vitro and that CX3CL1 signaling is positively or negatively regulated in EAE and MS, in HIV infection and LPS challenge, in epilepsy, in brain tumors, and in other neuropathologies. In this review we focus on the experimental evidence of CX3CL1 involvement in neuroprotection and survey the common molecular and cellular mechanisms described in different brain diseases.

  13. Bilateral Collicular Interaction: Modulation of Auditory Signal Processing in Amplitude Domain

    Science.gov (United States)

    Fu, Zi-Ying; Wang, Xin; Jen, Philip H.-S.; Chen, Qi-Cai

    2012-01-01

    In the ascending auditory pathway, the inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from many lower auditory nuclei, intrinsic projections within the IC, contralateral IC through the commissure of the IC and from the auditory cortex. All these connections make the IC a major center for subcortical temporal and spectral integration of auditory information. In this study, we examine bilateral collicular interaction in modulating amplitude-domain signal processing using electrophysiological recording, acoustic and focal electrical stimulation. Focal electrical stimulation of one (ipsilateral) IC produces widespread inhibition (61.6%) and focused facilitation (9.1%) of responses of neurons in the other (contralateral) IC, while 29.3% of the neurons were not affected. Bilateral collicular interaction produces a decrease in the response magnitude and an increase in the response latency of inhibited IC neurons but produces opposite effects on the response of facilitated IC neurons. These two groups of neurons are not separately located and are tonotopically organized within the IC. The modulation effect is most effective at low sound level and is dependent upon the interval between the acoustic and electric stimuli. The focal electrical stimulation of the ipsilateral IC compresses or expands the rate-level functions of contralateral IC neurons. The focal electrical stimulation also produces a shift in the minimum threshold and dynamic range of contralateral IC neurons for as long as 150 minutes. The degree of bilateral collicular interaction is dependent upon the difference in the best frequency between the electrically stimulated IC neurons and modulated IC neurons. These data suggest that bilateral collicular interaction mainly changes the ratio between excitation and inhibition during signal processing so as to sharpen the amplitude sensitivity of IC neurons. Bilateral interaction may be also involved in acoustic

  14. Physiological modules for generating discrete and rhythmic movements: Component analysis of EMG signals.

    Directory of Open Access Journals (Sweden)

    Ana eBengoetxea

    2015-01-01

    Full Text Available A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the CNS builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface EMG signals for seven different muscles acting around the shoulder.We first performed principal component analysis (PCA of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each shoulder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figure eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activation. From these results, we surmise that both ‘discrete-rhythmic movements’ such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the vertical and the other aligned with the

  15. Designed modulation of sex steroid signaling inhibits telomerase activity and proliferation of human prostate cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Vikas; Sharma, Vikas; Singh, Vishal [Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow 226 031 (India); Sharma, Siddharth; Bishnoi, Ajay Kumar [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226 031 (India); Chandra, Vishal; Maikhuri, J.P.; Dwivedi, Anila [Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow 226 031 (India); Kumar, Atul [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226 031 (India); Gupta, Gopal, E-mail: g_gupta@cdri.res.in [Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow 226 031 (India)

    2014-10-15

    The predominant estrogen-receptor (ER)-β signaling in normal prostate is countered by increased ER-α signaling in prostate cancer (CaP), which in association with androgen-receptor (AR) signaling results in pathogenesis of the disease. However CaP treatments mostly target AR signaling which is initially effective but eventually leads to androgen resistance, hence simultaneous targeting of ERs has been proposed. A novel series of molecules were designed with multiple sex-steroid receptor modulating capabilities by coalescing the pharmacophores of known anti-CaP molecules that act via modulation of ER(α/β) and/or AR, viz. 3,3′diindolylmethane (DIM), mifepristone, toremifene, tamoxifen and raloxifene. N,N-diethyl-4-((2-(4-methoxyphenyl)-1H-indol-3-yl)methyl) aniline (DIMA) was identified as the most promising structure of this new series. DIMA increased annexin-V labelling, cell-cycle arrest and caspase-3 activity, and decreased expression of AR and prostate specific antigen in LNCaP cells, in vitro. Concurrently, DIMA increased ER-β, p21 and p27 protein levels in LNCaP cells and exhibited ∼ 5 times more selective binding for ER-β than ER-α, in comparison to raloxifene. DIMA exhibited a dose-dependent ER-β agonism and ER-α antagonism in classical gene reporter assay and decreased hTERT (catalytic subunit of telomerase) transcript levels in LNCaP at 3.0 μM (P < 0.05). DIMA also dose-dependently decreased telomerase enzyme activity in prostate cancer cells. It is thus concluded that DIMA acts as a multi-steroid receptor modulator and effectively inhibits proliferation of prostate cancer cells through ER-β mediated telomerase inhibition, by countering actions of ER-α and AR. Its unique molecular design can serve as a lead structure for generation of potent agents against endocrine malignancies like the CaP.

  16. Emotional arousal state influences the ability of amygdalar endocannabinoid signaling to modulate anxiety.

    Science.gov (United States)

    Morena, Maria; Leitl, Kira D; Vecchiarelli, Haley A; Gray, J Megan; Campolongo, Patrizia; Hill, Matthew N

    2016-12-01

    Systemic activation of cannabinoid receptors often induces biphasic effects on emotional memory and anxiety depending on the levels of emotional arousal associated to the experimental context. The basolateral nucleus of the amygdala (BLA) represents a crucial structure for the ability of endocannabinoid (eCB) signaling to modulate emotional behaviour, and receives dense projections from brainstem arousal system nuclei. We examined whether changes in emotional arousal state would influence the ability of acute eCB manipulations within the BLA to modulate anxiety. Rats were tested in an elevated plus maze (EPM) under low or high arousal conditions. The low emotional arousal group was extensively handled and habituated to the experimental room and tested under red light condition, the high emotional arousal group was not handled or habituated and tested under high light condition. We examined amygdalar eCB anandamide (AEA) and 2-arachidonoylglycerol (2-AG) levels immediately after the EPM and the effects of intra-BLA administration of the AEA hydrolysis inhibitor URB597 or the 2-AG hydrolysis inhibitor KML29 on anxiety behaviour. The modulation of anxiety-like behaviour by eCBs in the BLA was strictly dependent on the environmental-associated emotional arousal. Pharmacologically-induced elevations of AEA or 2-AG in the BLA decreased anxiety under conditions of low emotional arousal. Conversely, when the level of emotional arousal increased, local eCB manipulation was ineffective in the modulation of the emotional arousal-induced anxiety response. These findings suggest that, depending on the emotional arousal state, eCB system is differentially activated to regulate the anxiety response in the amygdala and help to understand the state-dependency of many interventions on anxiety. Copyright © 2016. Published by Elsevier Ltd.

  17. Modulation of phytochrome signaling networks for improved biomass accumulation using a bioenergy crop model

    Energy Technology Data Exchange (ETDEWEB)

    Mockler, Todd C. [Donald Danforth Plant Science Center, Saint Louis, MO (United States)

    2016-11-07

    Plant growth and development, including stem elongation, flowering time, and shade-avoidance habits, are affected by wavelength composition (i.e., light quality) of the light environment. the molecular mechanisms underlying light perception and signaling pathways in plants have been best characterized in Arabidopsis thaliana where dozens of genes have been implicated in converging, complementary, and antagonistic pathways communicating light quality cues perceived by the phytochrome (red/far-red) cryptochrome (blue) and phototropin (blue) photorecptors. Light perception and signaling have been studied in grasses, including rice and sorghum but in much less detail than in Arabidopsis. During the course of the Mocker lab's DOE-funded wrok generating a gene expression atlas in Brachypodium distachyon we observed that Brachypodium plants grown in continuous monochromatic red light or continuous white light enriched in far-red light accumulated significantly more biomass and exhibited significantly greater seed yield than plants grown in monochromatic blue light or white light. This phenomenon was also observed in two other grasses, switchgrass and rice. We will systematically manipulate the expression of genes predicted to function in Brachypodium phytochrome signaling and assess the phenotypic consequences in transgenic Brachypodium plants in terms of morphology, stature, biomass accumulation, and cell wall composition. We will also interrogate direct interactions between candidate phytochrome signaling transcription factors and target promoters using a high-throughput yeast one-hybrid system. Brachypodium distachyon has emerged as a model grass species and is closely related to candidate feedstock crops for bioethanol production. Identification of genes capable of modifying growth characteristics of Brachypodium, when misexpressed, in particular increasing biomass accumulation, by modulating photoreceptor signaling will provide valuable candidates for

  18. Differential modulation of retinal degeneration by Ccl2 and Cx3cr1 chemokine signalling.

    Science.gov (United States)

    Luhmann, Ulrich F O; Lange, Clemens A; Robbie, Scott; Munro, Peter M G; Cowing, Jill A; Armer, Hannah E J; Luong, Vy; Carvalho, Livia S; MacLaren, Robert E; Fitzke, Frederick W; Bainbridge, James W B; Ali, Robin R

    2012-01-01

    Microglia and macrophages are recruited to sites of retinal degeneration where local cytokines and chemokines determine protective or neurotoxic microglia responses. Defining the role of Ccl2-Ccr2 and Cx3cl1-Cx3cr1 signalling for retinal pathology is of particular interest because of its potential role in age-related macular degeneration (AMD). Ccl2, Ccr2, and Cx3cr1 signalling defects impair macrophage trafficking, but have, in several conflicting studies, been reported to show different degrees of age-related retinal degeneration. Ccl2/Cx3cr1 double knockout (CCDKO) mice show an early onset retinal degeneration and have been suggested as a model for AMD. In order to understand phenotypic discrepancies in different chemokine knockout lines and to study how defects in Ccl2 and/or Cx3cr1 signalling contribute to the described early onset retinal degeneration, we defined primary and secondary pathological events in CCDKO mice. To control for genetic background variability, we compared the original phenotype with that of single Ccl2, Cx3cr1 and Ccl2/Cx3cr1 double knockout mice obtained from backcrosses of CCDKO with C57Bl/6 mice. We found that the primary pathological event in CCDKO mice develops in the inferior outer nuclear layer independently of light around postnatal day P14. RPE and vascular lesions develop secondarily with increasing penetrance with age and are clinically similar to retinal telangiectasia not to choroidal neovascularisation. Furthermore, we provide evidence that a third autosomal recessive gene causes the degeneration in CCDKO mice and in all affected re-derived lines and subsequently demonstrated co-segregation of the naturally occurring RD8 mutation in the Crb1 gene. By comparing CCDKO mice with re-derived CCl2(-/-)/Crb1(Rd8/RD8), Cx3cr1(-/-)/Crb1(Rd8/RD8) and CCl2(-/-)/Cx3cr1(-/-)/Crb1(Rd8/RD8) mice, we observed a differential modulation of the retinal phenotype by genetic background and both chemokine signalling pathways. These findings

  19. Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions

    Directory of Open Access Journals (Sweden)

    Barja-Fidalgo C.

    2005-01-01

    Full Text Available Extracellular matrix proteins and cell adhesion receptors (integrins play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as focal adhesion kinase, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight, cysteine-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.

  20. Deregulation of the Ras-Erk Signaling Axis Modulates the Enhancer Landscape

    Directory of Open Access Journals (Sweden)

    Behnam Nabet

    2015-08-01

    Full Text Available Unrestrained receptor tyrosine kinase (RTK signaling and epigenetic deregulation are root causes of tumorigenesis. We establish linkage between these processes by demonstrating that aberrant RTK signaling unleashed by oncogenic HRasG12V or loss of negative feedback through Sprouty gene deletion remodels histone modifications associated with active typical and super-enhancers. However, although both lesions disrupt the Ras-Erk axis, the expression programs, enhancer signatures, and transcription factor networks modulated upon HRasG12V transformation or Sprouty deletion are largely distinct. Oncogenic HRasG12V elevates histone 3 lysine 27 acetylation (H3K27ac levels at enhancers near the transcription factor Gata4 and the kinase Prkcb, as well as their expression levels. We show that Gata4 is necessary for the aberrant gene expression and H3K27ac marking at enhancers, and Prkcb is required for the oncogenic effects of HRasG12V-driven cells. Taken together, our findings demonstrate that dynamic reprogramming of the cellular enhancer landscape is a major effect of oncogenic RTK signaling.

  1. Genetic Disruption of 2-Arachidonoylglycerol Synthesis Reveals a Key Role for Endocannabinoid Signaling in Anxiety Modulation

    Directory of Open Access Journals (Sweden)

    Brian C. Shonesy

    2014-12-01

    Full Text Available Endocannabinoid (eCB signaling has been heavily implicated in the modulation of anxiety and depressive behaviors and emotional learning. However, the role of the most-abundant endocannabinoid 2-arachidonoylglycerol (2-AG in the physiological regulation of affective behaviors is not well understood. Here, we show that genetic deletion of the 2-AG synthetic enzyme diacylglycerol lipase α (DAGLα in mice reduces brain, but not circulating, 2-AG levels. DAGLα deletion also results in anxiety-like and sex-specific anhedonic phenotypes associated with impaired activity-dependent eCB retrograde signaling at amygdala glutamatergic synapses. Importantly, acute pharmacological normalization of 2-AG levels reverses both phenotypes of DAGLα-deficient mice. These data suggest 2-AG deficiency could contribute to the pathogenesis of affective disorders and that pharmacological normalization of 2-AG signaling could represent an approach for the treatment of mood and anxiety disorders.

  2. Feature selection using angle modulated simulated Kalman filter for peak classification of EEG signals.

    Science.gov (United States)

    Adam, Asrul; Ibrahim, Zuwairie; Mokhtar, Norrima; Shapiai, Mohd Ibrahim; Mubin, Marizan; Saad, Ismail

    2016-01-01

    In the existing electroencephalogram (EEG) signals peak classification research, the existing models, such as Dumpala, Acir, Liu, and Dingle peak models, employ different set of features. However, all these models may not be able to offer good performance for various applications and it is found to be problem dependent. Therefore, the objective of this study is to combine all the associated features from the existing models before selecting the best combination of features. A new optimization algorithm, namely as angle modulated simulated Kalman filter (AMSKF) will be employed as feature selector. Also, the neural network random weight method is utilized in the proposed AMSKF technique as a classifier. In the conducted experiment, 11,781 samples of peak candidate are employed in this study for the validation purpose. The samples are collected from three different peak event-related EEG signals of 30 healthy subjects; (1) single eye blink, (2) double eye blink, and (3) eye movement signals. The experimental results have shown that the proposed AMSKF feature selector is able to find the best combination of features and performs at par with the existing related studies of epileptic EEG events classification.

  3. Paclitaxel modulates TGFbeta signaling in scleroderma skin grafts in immunodeficient mice.

    Directory of Open Access Journals (Sweden)

    2005-12-01

    Full Text Available BACKGROUND: Systemic sclerosis (SSc is characterized by excessive fibrosis and obliterative vascular lesions. Abnormal TGFbeta activation is implicated in the pathogenesis of SSc. Aberrant TGFbeta/Smad signaling can be controlled by stabilization of microtubules with paclitaxel. METHODS AND FINDINGS: SSc and healthy human skin biopsies were incubated in the presence or absence of paclitaxel followed by transplantation into severe combined immunodeficient mice. TGFbeta signaling, fibrosis, and neovessel formation were evaluated by quantitative RT-PCR and immunohistochemical staining. Paclitaxel markedly suppressed Smad2 and Smad3 phosphorylation and collagen deposition in SSc grafts. As a result, the autonomous maintenance/reconstitution of the SSc phenotype was prevented. Remarkably, SSc grafts showed a 2-fold increase in neovessel formation relative to normal grafts, regardless of paclitaxel treatment. Angiogenesis in SSc grafts was associated with a substantial increase in mouse PECAM-1 expression, indicating the mouse origin of the neovascular cells. CONCLUSION: Low-dose paclitaxel can significantly suppress TGFbeta/Smad activity and lessen fibrosis in SCID mice. Transplantation of SSc skin into SCID mice elicits a strong angiogenesis-an effect not affected by paclitaxel. Although prolonged chemotherapy with paclitaxel at higher doses is associated with pro-fibrotic and anti-angiogenic changes, the findings described here indicate that low-dose paclitaxel may have therapeutic benefits for SSc via modulating TGFbeta signaling.

  4. Raf kinase inhibitory protein: a signal transduction modulator and metastasis suppressor

    Institute of Scientific and Technical Information of China (English)

    Alexey E Granovsky; Marsha Rich Rosner

    2008-01-01

    Cells have a multitude of controls to maintain their integrity and prevent random switching from one biological state to another. Raf Kinase Inhibitory Protein (RKIP), a member of the phosphatidylethanolamine binding protein (PEBP) family, is representative of a new class of modulators of signaling cascades that function to maintain the "yin yang" or balance of biological systems. RKIP inhibits MAP kinase (Raf-MEK-ERK), G protein-coupled receptor (GPCR) kinase and NFkB signaling cascades. Because RKIP targets different kinases dependent upon its state of phosphorylation, RKIP also acts to integrate crosstalk initiated by multiple environmental stimuli. Loss or depletion of RKIP results in disruption of the normal cellular stasis and can lead to chromosomal abnormalities and disease states such as cancer. Since RKIP and the PEBP family have been reviewed previously, the goal of this analysis is to provide an update and highlight some of the unique features of RKIP that make it a critical player in the regulation of cellular signaling processes.

  5. Polarization-Modulation Method of Measuring the Bearing of a Moving Object From Orthogonal Elliptically Polarized Signals of a Radio Beacon

    Science.gov (United States)

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

    2017-05-01

    A polarization-modulation method of estimating the bearing of a moving object using a radio beacon transmitting two mutually orthogonal elliptically polarized radio signals is considered. The signals received onboard the moving object are subject to polarization modulation. The bearing is estimated at the output from a single-channel receiver at the frequency multiple to the polarization modulation frequency.

  6. Dopamine receptors modulate cytotoxicity of natural killer cells via cAMP-PKA-CREB signaling pathway.

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    Full Text Available Dopamine (DA, a neurotransmitter in the nervous system, has been shown to modulate immune function. We have previously reported that five subtypes of DA receptors, including D1R, D2R, D3R, D4R and D5R, are expressed in T lymphocytes and they are involved in regulation of T cells. However, roles of these DA receptor subtypes and their coupled signal-transduction pathway in modulation of natural killer (NK cells still remain to be clarified. The spleen of mice was harvested and NK cells were isolated and purified by negative selection using magnetic activated cell sorting. After NK cells were incubated with various drugs for 4 h, flow cytometry measured cytotoxicity of NK cells against YAC-1 lymphoma cells. NK cells expressed the five subtypes of DA receptors at mRNA and protein levels. Activation of D1-like receptors (including D1R and D5R with agonist SKF38393 enhanced NK cell cytotoxicity, but activation of D2-like receptors (including D2R, D3R and D4R with agonist quinpirole attenuated NK cells. Simultaneously, SKF38393 elevated D1R and D5R expression, cAMP content, and phosphorylated cAMP-response element-binding (CREB level in NK cells, while quinpirole reduced D3R and D4R expression, cAMP content, and phosphorylated CREB level in NK cells. These effects of SKF38393 were blocked by SCH23390, an antagonist of D1-like receptors, and quinpirole effects were abolished by haloperidol, an antagonist of D2-like receptors. In support these results, H89, an inhibitor of phosphokinase A (PKA, prevented the SKF38393-dependent enhancement of NK cells and forskolin, an activator of adenylyl cyclase (AC, counteracted the quinpirole-dependent suppression of NK cells. These findings show that DA receptor subtypes are involved in modulation of NK cells and suggest that D1-like receptors facilitate NK cells by stimulating D1R/D5R-cAMP-PKA-CREB signaling pathway and D2-like receptors suppress NK cells by inhibiting D3R/D4R-cAMP-PKA-CREB signaling pathway. The

  7. Generation and distribution of a wide-band continuously tunable millimeter-wave signal with an optical external modulation technique

    Science.gov (United States)

    Qi, Guohua; Yao, Jianping; Seregelyi, J.; Paquet, S.; Belisle, C.

    2005-10-01

    A new technique to generate and distribute a wide-band continuously tunable millimeter-wave signal using an optical external modulator and a wavelength-fixed optical notch filter is proposed. The optical intensity modulator is biased to suppress the odd-order optical sidebands. The wavelength-fixed optical notch filter is then used to filter out the optical carrier. Two second-order optical sidebands are obtained at the output of the notch filter. A millimeter-wave signal that has four times the frequency of the microwave drive signal is generated by beating the two second-order optical sidebands at a photodetector. Since no tunable optical filter is used, the system is easy to implement. A system using an LiNbO3 intensity modulator and a fiber Bragg grating filter is built. A stable and high spectral purity millimeter-wave signal tunable from 32 to 50 GHz is obtained by tuning the microwave drive signal from 8 to 12.5 GHz. The integrity of the generated millimeter-wave signal is maintained after transmission over a 25-km standard single-mode fiber. Theoretical analysis on the harmonic suppression with different modulation depths and filter attenuations is also discussed.

  8. Growth hormone STAT5-mediated signaling and its modulation in mice liver during the growth period.

    Science.gov (United States)

    Martinez, Carolina S; Piazza, Verónica G; Ratner, Laura D; Matos, Marina N; González, Lorena; Rulli, Susana B; Miquet, Johanna G; Sotelo, Ana I

    2013-01-01

    Postnatal growth exhibits two instances of rapid growth in mice: the first is perinatal and independent of growth hormone (GH), the second is peripuberal and GH-dependent. Signal transducer and activator of transcription 5b (STAT5b) is the main GH-signaling mediator and it is related to IGF1 synthesis and somatic growth. The aim of this work was to assess differential STAT5 sensitivity to GH during the growth period in mouse liver of both sexes. Three representative ages were selected: 1-week-old animals, in the GH-independent phase of growth; 2.5-week-old mice, at the onset of the GH-dependent phase of growth; and 9-week-old young adults. GH-signaling mediators were assessed by immunoblotting, quantitative RT-PCR and immunohistochemistry. GH-induced STAT5 phosphorylation is low at one-week and maximal at 2.5-weeks of age when compared to young adults, accompanied by higher protein content at the onset of growth. Suppressor CIS and phosphatase PTP1B exhibit high levels in one-week animals, which gradually decline, while SOCS2 and SOCS3 display higher levels at adulthood. Nuclear phosphorylated STAT5 is low in one-week animals while in 2.5-week animals it is similar to 9-week control; expression of SOCS3, an early response GH-target gene, mimics this pattern. STAT5 coactivators glucocorticoid receptor (GR) and hepatic nuclear factor 1 (HNF1) abundance is higher in adulthood. Therefore, GH-induced STAT5 signaling presents age-dependent activity in liver, with its maximum coinciding with the onset of GH-dependent phase of growth, accompanied by an age-dependent variation of modulating factors. This work contributes to elucidate the molecular mechanisms implicated in GH responsiveness during growth.

  9. PINK1 positively regulates IL-1β-mediated signaling through Tollip and IRAK1 modulation

    Directory of Open Access Journals (Sweden)

    Lee Hyun Jung

    2012-12-01

    Full Text Available Abstract Background Parkinson disease (PD is characterized by a slow, progressive degeneration of dopaminergic neurons in the substantianigra. The cause of neuronal loss in PD is not well understood, but several genetic loci, including PTEN-induced putative kinase 1 (PINK1, have been linked to early-onset autosomal recessive forms of familial PD. Neuroinflammation greatly contributes to PD neuronal degeneration and pathogenesis. IL-1 is one of the principal cytokines that regulates various immune and inflammatory responses via the activation of the transcription factors NF-κB and activating protein-1. Despite the close relationship between PD and neuroinflammation, the functional roles of PD-linked genes during inflammatory processes remain poorly understood. Methods To explore the functional roles of PINK1 in response to IL-1β stimulation, HEK293 cells, mouse embryonic fibroblasts derived from PINK1-null (PINK1−/− and control (PINK1+/+ mice, and 293 IL-1RI cells stably expressing type 1 IL-1 receptor were used. Immunoprecipitation and western blot analysis were performed to detect protein–protein interaction and protein ubiquitination. To confirm the effect of PINK1 on NF-κB activation, NF-κB-dependent firefly luciferase reporter assay was conducted. Results PINK1 specifically binds two components of the IL-1-mediated signaling cascade, Toll-interacting protein (Tollip and IL-1 receptor-associated kinase 1 (IRAK1. The association of PINK1 with Tollip, a negative regulator of IL-1β signaling, increases upon IL-1β stimulation, which then facilitates the dissociation of Tollip from IRAK1 as well as the assembly of the IRAK1–TNF receptor-associated factor 6 (TRAF6 complex. PINK1 also enhances Lys63-linked polyubiquitination of IRAK1, an essential modification of recruitment of NF-κB essential modulator and subsequent IκB kinase activation, and increases formation of the intermediate signalosome including IRAK1, TRAF6, and

  10. Dynamic characteristics of two-state lasing quantum dot lasers under large signal modulation

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Zun-Ren; Ji, Hai-Ming, E-mail: jhm@semi.ac.cn; Luo, Shuai; Gao, Feng; Xu, Feng; Yang, Tao, E-mail: tyang@semi.ac.cn [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Xiao, De-Hang, E-mail: xiaodehang@hlju.edu.cn [College of Physical Science and Technology, Heilongjiang University, Harbin 150080 (China)

    2015-10-15

    Large signal modulation characteristics of the simultaneous ground-state (GS) and excited-state (ES) lasing quantum dot lasers are theoretically investigated. Relaxation oscillations of ‘0 → 1’ and ‘1 → 0’ in the GS lasing region (Region I), the transition region from GS lasing to two-state lasing (Region II) and the two-state lasing region (Region III) are compared and analyzed. It is found that the overshooting power and settling time in both Regions I and III decrease as the bias current increases. However, there exist abnormal behaviors of the overshooting power and settling time in Region II owing to the occurrence of ES lasing, which lead to fuzzy eye diagrams of the GS and ES lasing. Moreover, the ES lasing in Region III possesses much better eye diagrams because of its shorter settling time and smaller overshooting power over the GS lasing in Region I.

  11. PDF-1 neuropeptide signaling modulates a neural circuit for mate-searching behavior in C. elegans.

    Science.gov (United States)

    Barrios, Arantza; Ghosh, Rajarshi; Fang, Chunhui; Emmons, Scott W; Barr, Maureen M

    2012-12-01

    Appetitive behaviors require complex decision making that involves the integration of environmental stimuli and physiological needs. C. elegans mate searching is a male-specific exploratory behavior regulated by two competing needs: food and reproductive appetite. We found that the pigment dispersing factor receptor (PDFR-1) modulates the circuit that encodes the male reproductive drive that promotes male exploration following mate deprivation. PDFR-1 and its ligand, PDF-1, stimulated mate searching in the male, but not in the hermaphrodite. pdf-1 was required in the gender-shared interneuron AIM, and the receptor acted in internal and external environment-sensing neurons of the shared nervous system (URY, PQR and PHA) to produce mate-searching behavior. Thus, the pdf-1 and pdfr-1 pathway functions in non-sex-specific neurons to produce a male-specific, goal-oriented exploratory behavior. Our results indicate that secretin neuropeptidergic signaling is involved in regulating motivational internal states.

  12. Designing Non-linear Frequency Modulated Signals For Medical Ultrasound Imaging

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2006-01-01

    is tested experimentally using the RASMUS ultrasound system with a 7 MHz linear array transducer. Synthetic transmit aperture ultrasound imaging is applied to acquire data. The proposed design method was compared to a linear FM signal. Due to more efficient spectral usage, a gain in SNR of 4.3plusmn1.2 d......In this paper a new method for designing non-linear frequency modulated (NLFM) waveforms for ultrasound imaging is proposed. The objective is to control the amplitude spectrum of the designed waveform and still keep a constant transmit amplitude, so that the transmitted energy is maximized...... in the transducer can be decreased. Secondly, by choosing an appropriate amplitude spectrum, no additional temporal tapering has to be applied to the matched filter to achieve sufficient range sidelobe suppression. Proper design results in waveforms with a range sidelobe level beyond -80 dB. The design method...

  13. 25 Gbit/s differential phase-shift-keying signal generation using directly modulated quantum-dot semiconductor optical amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Zeghuzi, A., E-mail: zeghuzi@mailbox.tu-berlin.de; Schmeckebier, H.; Stubenrauch, M.; Bimberg, D. [Department of Solid-State Physics, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Meuer, C.; Schubert, C. [Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, 10587 Berlin (Germany); Bunge, C.-A. [Hochschule fuer Telekommunikation Leipzig (HfTL), Gustav-Freytag-Str. 43-45, 04277 Leipzig (Germany)

    2015-05-25

    Error-free generation of 25-Gbit/s differential phase-shift keying (DPSK) signals via direct modulation of InAs quantum-dot (QD) based semiconductor optical amplifiers (SOAs) is experimentally demonstrated with an input power level of −5 dBm. The QD SOAs emit in the 1.3-μm wavelength range and provide a small-signal fiber-to-fiber gain of 8 dB. Furthermore, error-free DPSK modulation is achieved for constant optical input power levels from 3 dBm down to only −11 dBm for a bit rate of 20 Gbit/s. Direct phase modulation of QD SOAs via current changes is thus demonstrated to be much faster than direct gain modulation.

  14. Increasing signal processing sophistication in the calculation of the respiratory modulation of the photoplethysmogram (DPOP).

    Science.gov (United States)

    Addison, Paul S; Wang, Rui; Uribe, Alberto A; Bergese, Sergio D

    2015-06-01

    DPOP (∆POP or Delta-POP) is a non-invasive parameter which measures the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive surrogate parameter for pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. Many groups have reported on the DPOP parameter and its correlation with PPV using various semi-automated algorithmic implementations. The study reported here demonstrates the performance gains made by adding increasingly sophisticated signal processing components to a fully automated DPOP algorithm. A DPOP algorithm was coded and its performance systematically enhanced through a series of code module alterations and additions. Each algorithm iteration was tested on data from 20 mechanically ventilated OR patients. Correlation coefficients and ROC curve statistics were computed at each stage. For the purposes of the analysis we split the data into a manually selected 'stable' region subset of the data containing relatively noise free segments and a 'global' set incorporating the whole data record. Performance gains were measured in terms of correlation against PPV measurements in OR patients undergoing controlled mechanical ventilation. Through increasingly advanced pre-processing and post-processing enhancements to the algorithm, the correlation coefficient between DPOP and PPV improved from a baseline value of R = 0.347 to R = 0.852 for the stable data set, and, correspondingly, R = 0.225 to R = 0.728 for the more challenging global data set. Marked gains in algorithm performance are achievable for manually selected stable regions of the signals using relatively simple algorithm enhancements. Significant additional algorithm enhancements, including a correction for low perfusion values, were required before similar gains were realised for the more challenging global data set.

  15. Beta2-adrenergic signaling affects the phenotype of human cardiac progenitor cells through EMT modulation.

    Science.gov (United States)

    Pagano, Francesca; Angelini, Francesco; Siciliano, Camilla; Tasciotti, Julia; Mangino, Giorgio; De Falco, Elena; Carnevale, Roberto; Sciarretta, Sebastiano; Frati, Giacomo; Chimenti, Isotta

    2017-01-15

    Human cardiac progenitor cells (CPCs) offer great promises to cardiac cell therapy for heart failure. Many in vivo studies have shown their therapeutic benefits, paving the way for clinical translation. The 3D model of cardiospheres (CSs) represents a unique niche-like in vitro microenvironment, which includes CPCs and supporting cells. CSs have been shown to form through a process mediated by epithelial-to-mesenchymal transition (EMT). β2-Adrenergic signaling significantly affects stem/progenitor cells activation and mobilization in multiple tissues, and crosstalk between β2-adrenergic signaling and EMT processes has been reported. In the present study, we aimed at investigating the biological response of CSs to β2-adrenergic stimuli, focusing on EMT modulation in the 3D culture system of CSs. We treated human CSs and CS-derived cells (CDCs) with the β2-blocker butoxamine (BUT), using either untreated or β2 agonist (clenbuterol) treated CDCs as control. BUT-treated CS-forming cells displayed increased migration capacity and a significant increase in their CS-forming ability, consistently associated with increased expression of EMT-related genes, such as Snai1. Moreover, long-term BUT-treated CDCs contained a lower percentage of CD90+ cells, and this feature has been previously correlated with higher cardiogenic and therapeutic potential of the CDCs population. In addition, long-term BUT-treated CDCs had an increased ratio of collagen-III/collagen-I gene expression levels, and showed decreased release of inflammatory cytokines, overall supporting a less fibrosis-prone phenotype. In conclusion, β2 adrenergic receptor block positively affected the stemness vs commitment balance within CSs through the modulation of type1-EMT (so called "developmental"). These results further highlight type-1 EMT to be a key process affecting the features of resident cardiac progenitor cells, and mediating their response to the microenvironment.

  16. Search for an annual modulation of dark-matter signals with a germanium spectrometer at the Sierra Grande Laboratory

    CERN Document Server

    Abriola, D; Brodzinski, R L; Collar, J I; Gregorio, D E D; Farach, H A; García, E; Gattone, A O; Guérard, C K; Hasenbalg, F; Huck, H; Miley, H S; Morales, A; Morales, J; De Solorzano, A O; Puimedón, J; Reeves, J H; Salinas, A; Sarsa, M L; Villar, J A

    1999-01-01

    Data collected during three years with a germanium spectrometer at the Sierra Grande underground laboratory have been analyzed for distinctive features of annual modulation of the signal induced by WIMP dark matter candidates. The main motivation for this analysis was the recent suggestion by the DAMA/NaI Collaboration that a yearly modulation signal could not be rejected at the 90% confidence level when analyzing data obtained with a high-mass low-background scintillator detector. We performed two different analyses of the data: First, the statistical distribution of modulation-significance variables (expected from an experiment running under the conditions of Sierra Grande) was compared with the same variables obtained from the data. Second, the data were analyzed in energy bins as an independent check of the first result and to allow for the possibility of a crossover in the expected signal. In both cases no statistically significant deviation from the null result was found, which could support the hypothe...

  17. Lipo-chitin oligosaccharides, plant symbiosis signalling molecules that modulate mammalian angiogenesis in vitro.

    Directory of Open Access Journals (Sweden)

    Michael A Djordjevic

    Full Text Available Lipochitin oligosaccharides (LCOs are signaling molecules required by ecologically and agronomically important bacteria and fungi to establish symbioses with diverse land plants. In plants, oligo-chitins and LCOs can differentially interact with different lysin motif (LysM receptors and affect innate immunity responses or symbiosis-related pathways. In animals, oligo-chitins also induce innate immunity and other physiological responses but LCO recognition has not been demonstrated. Here LCO and LCO-like compounds are shown to be biologically active in mammals in a structure dependent way through the modulation of angiogenesis, a tightly-regulated process involving the induction and growth of new blood vessels from existing vessels. The testing of 24 LCO, LCO-like or oligo-chitin compounds resulted in structure-dependent effects on angiogenesis in vitro leading to promotion, or inhibition or nil effects. Like plants, the mammalian LCO biological activity depended upon the presence and type of terminal substitutions. Un-substituted oligo-chitins of similar chain lengths were unable to modulate angiogenesis indicating that mammalian cells, like plant cells, can distinguish between LCOs and un-substituted oligo-chitins. The cellular mode-of-action of the biologically active LCOs in mammals was determined. The stimulation or inhibition of endothelial cell adhesion to vitronectin or fibronectin correlated with their pro- or anti-angiogenic activity. Importantly, novel and more easily synthesised LCO-like disaccharide molecules were also biologically active and de-acetylated chitobiose was shown to be the primary structural basis of recognition. Given this, simpler chitin disaccharides derivatives based on the structure of biologically active LCOs were synthesised and purified and these showed biological activity in mammalian cells. Since important chronic disease states are linked to either insufficient or excessive angiogenesis, LCO and LCO

  18. Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

    Science.gov (United States)

    Capra, N F; Ro, J Y

    2000-05-01

    The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the

  19. Olfactory signal modulation by molluscan cardioexcitatory tetrapeptide (FMRFamide) in axolotls (Ambystoma mexicanum).

    Science.gov (United States)

    Park, Daesik; Zawacki, Sarah R; Eisthen, Heather L

    2003-05-01

    The terminal nerve, which innervates the nasal epithelia of most jawed vertebrates, is believed to release neuropeptides that modulate activity of sensory receptor neurons. The terminal nerve usually contains gonadotropin-releasing hormone as well as at least one other peptide that has not been characterized, but which bears some structural similarity to molluscan cardioexcitatory tetrapeptide (FMRFamide) and neuropeptide tyrosine (NPY). We investigated the effects of FMRFamide on both voltage-gated currents and odorant responses in the olfactory epithelium of axolotls (Ambystoma mexicanum), using whole-cell patch clamp and electro-olfactogram (EOG) recording techniques. In the presence of FMRFamide, the magnitude of a voltage-gated inward current was dramatically increased, reaching an average of 136% of the initial (pre-exposure) magnitude in neurons that showed a response to the peptide. This increase is detectable within approximately 1-2 min of exposure to FMRFamide and is sustained for at least 10 min. In EOG experiments, odorant responses are not affected during FMRFamide application, but are sometimes increased or decreased during the subsequent wash period. On average, the largest single EOG response in each trial was detected approximately 25 min after initial FMRFamide application, and ranged from 110 to 147% of baseline. These results suggest that a compound similar to FMRFamide, if released from the terminal nerve, may function in peripheral olfactory signal modulation.

  20. Noise-immunity processing of digital multilevel pulse-amplitude modulation signals

    Directory of Open Access Journals (Sweden)

    A. S. Makarenko

    2015-12-01

    Full Text Available Introduction. The main properties and features of spectral-effective multi-level pulse amplitude modulation digital signals at coherent reception are presented. It is shown that the phase locked loop circuit (PLL circuit used in the receiver is able to work at SNR > 5 dB.Object of the paper. We propose a new scheme of noise compensator at an intermediate frequency, allowing us to obtain increasing of SNR on 15–25 dB when error of PLL is equal zero. The noise compensator has the gain 8–18 dB at error of PLL = 33° that is able to work at SNR = 5 dB. As result, we can obtain a required SNR for determined BER in systems with multi-level PAM.Conclusions. This technical solution makes a spectrally-efficient system using multi-level amplitude modulation is also energy efficient, forward-looking and competitive. The power transmitters of cell phones and radio relay lines of mobile communication systems can be reduced by 10 times or at the same transmitter power improvement the quality of communication or range is presented.

  1. Reduction of Static Power with Minimized Ground Bounce Noise Using Sleep Signal Slew Rate Modulation In 45nm Technology

    Directory of Open Access Journals (Sweden)

    M. Naga Pramod Reddy

    2014-06-01

    Full Text Available In MTCMOS Integrated Circuit design there exists a significant trade-off between static power consumption and technology scaling. In Modern circuits increase in power dissipation is significant due to combination of higher clock speeds, greater functional integration and smaller process geometries resulting in dominant static power consumption component. This is a big challenge for the circuit designer. However, the designers do have few methods like sleep transistor approach, sleepy stack approach to reduce this static power consumption. However all of these methods do have their own drawbacks. In order to achieve lower static power consumptions one has to sacrifice area and circuit performance metrics. In this paper we propose a new enhancement to available static power reduction techniques by modulating the sleep signal slew rate. We have designed the basic CMOS circuits in MTCMOS to achieve significant reduction in Static power consumption. For Sleep signal slew rate modulation we have proposed a modulator called triple phase sleep signal slew rate modulator. By using this Triple Phase Sleep signal modulator(TPS we can control the noise at ground distribution network (ground bounce noise produced during sleep to active state transition. By using TPS we can decrease the reactivation time to a recognizable extent, along with reduced power (static and dynamic dissipation.

  2. Realization of High-Order Filters for 1-bit Signal Processing Based on Delta-Sigma Modulation

    Science.gov (United States)

    Murahashi, Yoshimitsu; Doki, Shinji; Okuma, Shigeru

    We discuss a realization method of basic 1-bit signal processing based on Delta-Sigma modulation in this paper. Additionally, we show the characteristics of basic 1-bit processor and an effective design method from the view point of SNR. As the application of the 1-bit signal processing, we proposed a realization method of high-order filters based on Delta-Sigma modulation. We applied the effective design method to decide coefficients of a 4th-order butterworth low pass filter. We show that the filter designed by using the proposed method achieves the highest SNR.

  3. Nonlinearity and Phase Noise Tolerant 75-110 GHz Signal over Fiber System Using Phase Modulation Technique

    DEFF Research Database (Denmark)

    Deng, Lei; Pang, Xiaodan; Zhang, Xu

    2013-01-01

    We report on the transmission of 8 Gb/s 0 dB PAPR 16QAM-OFDM W-band (75-110 GHz) signals over 22.8km SMF without phase noise compensation by using a phase modulator in the optical heterodyne up-convertor.......We report on the transmission of 8 Gb/s 0 dB PAPR 16QAM-OFDM W-band (75-110 GHz) signals over 22.8km SMF without phase noise compensation by using a phase modulator in the optical heterodyne up-convertor....

  4. Modulation of Root Signals in Relation to Stomatal Sensitivity to Root-sourced Abscisic Acid in Drought-affected Plants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stomatal sensitivity to root signals induced by soil drying may vary between environments and plant species. This is likely central role in root to shoot signaling. pH and hydraulic signals may interact with ABA signals and thus, jointly regulate stomatal responses to changed soil water status. pH itself can be modified by several factors, among which the chemical compositions In the xylem stream and the live cells surrounding the vessels play crucial roles. In addition to the xylem pH,more attention should be paid to the direct modulation of leaf apoplastic pH, because many chemical compositions might strongly modify the leaf apoplastlc pH while having no significant effect on the xylem pH. The direct modulation of the ABA signal intensity may be more important for the regulation of stomatal responses to soil drying than the ABA signal per se.The ABA signal is also regulated by the ABA catabolism and the supply of precursors to the roots If a sustained root to shoot communication of soil drying operates at the whole plant level. More importantly, ABA catabolism could play crucial roles In the determination of the fate of the ABA signal and thereby control the stomatal behavior of the root-sourced ABA signal.

  5. IQGAP1 functions as a modulator of dishevelled nuclear localization in Wnt signaling.

    Directory of Open Access Journals (Sweden)

    Toshiyasu Goto

    Full Text Available Dishevelled (DVL is a central factor in the Wnt signaling pathway, which is highly conserved among various organisms. DVL plays important roles in transcriptional activation in the nucleus, but the molecular mechanisms underlying their nuclear localization remain unclear. In the present study, we identified IQGAP1 as a regulator of DVL function. In Xenopus embryos, depletion of IQGAP1 reduced Wnt-induced nuclear accumulation of DVL, and expression of Wnt target genes during early embryogenesis. The domains in DVL and IQGAP1 that mediated their interaction are also required for their nuclear localization. Endogenous expression of Wnt target genes was reduced by depletion of IQGAP1 during early embryogenesis, but notably not by depletion of other IQGAP family genes. Moreover, expression of Wnt target genes caused by depletion of endogenous IQGAP1 could be rescued by expression of wild-type IQGAP1, but not IQGAP1 deleting DVL binding region. These results provide the first evidence that IQGAP1 functions as a modulator in the canonical Wnt signaling pathway.

  6. Azithromycin Modulates 3',5'-cyclic Diguanylic Acid Signaling in Pseudomonas aeruginosa.

    Science.gov (United States)

    Kimura, Soichiro; Mori, Nobuaki; Kai, Toshihiro; Ishii, Yoshikazu; Yamaguchi, Keizo; Tateda, Kazuhiro

    2017-08-01

    Macrolides have been reported to exert a variety of effects on both host immunomodulation and repression of bacterial pathogenicity. In this study, we report that the 3',5'-cyclic diguanylic acid (c-di-GMP) signaling system, which regulates virulence in Pseudomonas aeruginosa, is affected by the macrolide azithromycin. Using DNA microarray analysis, we selected a gene encoding PA2567 related to c-di-GMP metabolism that was significantly affected by azithromycin treatment. Expression of the PA2567 gene was significantly repressed by azithromycin in a time- and dose-dependent manner, whereas no difference in PA2567 gene expression was observed in the absence of azithromycin. In-frame deletion of the PA2567 gene affected both virulence factors and the quorum-sensing system, and significantly decreased total bacteria in a mouse pneumonia model compared to the wild-type strain (P < 0.05). These results suggest that macrolides possess the ability to modulate c-di-GMP intracellular signaling in P. aeruginosa. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  7. Negative feedback regulation of auxin signaling by ATHB8/ACL5-BUD2 transcription module.

    Science.gov (United States)

    Baima, Simona; Forte, Valentina; Possenti, Marco; Peñalosa, Andrés; Leoni, Guido; Salvi, Sergio; Felici, Barbara; Ruberti, Ida; Morelli, Giorgio

    2014-06-01

    The role of auxin as main regulator of vascular differentiation is well established, and a direct correlation between the rate of xylem differentiation and the amount of auxin reaching the (pro)cambial cells has been proposed. It has been suggested that thermospermine produced by ACAULIS5 (ACL5) and bushy and dwarf2 (BUD2) is one of the factors downstream to auxin contributing to the regulation of this process in Arabidopsis. Here, we provide an in-depth characterization of the mechanism through which ACL5 modulates xylem differentiation. We show that an increased level of ACL5 slows down xylem differentiation by negatively affecting the expression of homeodomain-leucine zipper (HD-ZIP) III and key auxin signaling genes. This mechanism involves the positive regulation of thermospermine biosynthesis by the HD-ZIP III protein Arabidopsis thaliana homeobox8 tightly controlling the expression of ACL5 and BUD2. In addition, we show that the HD-ZIP III protein REVOLUTA contributes to the increased leaf vascularization and long hypocotyl phenotype of acl5 likely by a direct regulation of auxin signaling genes such as like auxin resistant2 (LAX2) and LAX3. We propose that proper formation and differentiation of xylem depend on a balance between positive and negative feedback loops operating through HD-ZIP III genes.

  8. BeiDou Signal Acquisition with Neumann–Hoffman Code Modulation in a Degraded Channel

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2017-02-01

    Full Text Available With the modernization of global navigation satellite systems (GNSS, secondary codes, also known as the Neumann–Hoffman (NH codes, are modulated on the satellite signal to obtain a better positioning performance. However, this leads to an attenuation of the acquisition sensitivity of classic integration algorithms because of the frequent bit transitions that refer to the NH codes. Taking weak BeiDou navigation satellite system (BDS signals as objects, the present study analyzes the side effect of NH codes on acquisition in detail and derives a straightforward formula, which indicates that bit transitions decrease the frequency accuracy. To meet the requirement of carrier-tracking loop initialization, a frequency recalculation algorithm is proposed based on verified fast Fourier transform (FFT to mitigate the effect, meanwhile, the starting point of NH codes is found. Then, a differential correction is utilized to improve the acquisition accuracy of code phase. Monte Carlo simulations and real BDS data tests demonstrate that the new structure is superior to the conventional algorithms both in detection probability and frequency accuracy in a degraded channel.

  9. Extracellular vesicles: Pharmacological modulators of the peripheral and central signals governing obesity.

    Science.gov (United States)

    Milbank, Edward; Martinez, M Carmen; Andriantsitohaina, Ramaroson

    2016-01-01

    Obesity and its metabolic resultant dysfunctions such as insulin resistance, hyperglycemia, dyslipidemia and hypertension, grouped as the "metabolic syndrome", are chronic inflammatory disorders that represent one of the most severe epidemic health problems. The imbalance between energy intake and expenditure, leading to an excess of body fat and an increase of cardiovascular and diabetes risks, is regulated by the interaction between central nervous system (CNS) and peripheral signals in order to regulate behavior and finally, the metabolism of peripheral organs. At present, pharmacological treatment of obesity comprises actions in both CNS and peripheral organs. In the last decades, the extracellular vesicles have emerged as participants in many pathophysiological regulation processes. Whether used as biomarkers, targets or even tools, extracellular vesicles provided some promising effects in the treatment of a large variety of diseases. Extracellular vesicles are released by cells from the plasma membrane (microvesicles) or from multivesicular bodies (exosomes) and contain lipids, proteins and nucleic acids, such as DNA, protein coding, and non-coding RNAs. Owing to their composition, extracellular vesicles can (i) activate receptors at the target cell and then, the subsequent intracellular pathway associated to the specific receptor; (ii) transfer molecules to the target cells and thereby change their phenotype and (iii) be used as shuttle of drugs and, thus, to carry specific molecules towards specific cells. Herein, we review the impact of extracellular vesicles in modulating the central and peripheral signals governing obesity.

  10. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation

    Science.gov (United States)

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose. PMID:28072818

  11. Cannabinoid CB1 receptor signaling dichotomously modulates inhibitory and excitatory synaptic transmission in rat inner retina.

    Science.gov (United States)

    Wang, Xiao-Han; Wu, Yi; Yang, Xiao-Fang; Miao, Yanying; Zhang, Chuan-Qiang; Dong, Ling-Dan; Yang, Xiong-Li; Wang, Zhongfeng

    2016-01-01

    In the inner retina, ganglion cells (RGCs) integrate and process excitatory signal from bipolar cells (BCs) and inhibitory signal from amacrine cells (ACs). Using multiple labeling immunohistochemistry, we first revealed the expression of the cannabinoid CB1 receptor (CB1R) at the terminals of ACs and BCs in rat retina. By patch-clamp techniques, we then showed how the activation of this receptor dichotomously regulated miniature inhibitory postsynaptic currents (mIPSCs), mediated by GABAA receptors and glycine receptors, and miniature excitatory postsynaptic currents (mEPSCs), mediated by AMPA receptors, of RGCs in rat retinal slices. WIN55212-2 (WIN), a CB1R agonist, reduced the mIPSC frequency due to an inhibition of L-type Ca(2+) channels no matter whether AMPA receptors were blocked. In contrast, WIN reduced the mEPSC frequency by suppressing T-type Ca(2+) channels only when inhibitory inputs to RGCs were present, which could be in part due to less T-type Ca(2+) channels of cone BCs, presynaptic to RGCs, being in an inactivation state under such condition. This unique feature of CB1R-mediated retrograde regulation provides a novel mechanism for modulating excitatory synaptic transmission in the inner retina. Moreover, depolarization of RGCs suppressed mIPSCs of these cells, an effect that was eliminated by the CB1R antagonist SR141716, suggesting that endocannabinoid is indeed released from RGCs.

  12. Parametric excitation of relaxation oscillations at the subharmonic of the external modulating signal in a ring Nd : YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Aulova, T V; Kravtsov, Nikolai V; Lariontsev, E G; Chekina, S N [D.V. Skobel' tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2012-08-31

    The dynamics of solid-state ring laser (SSRL) radiation with periodic pump modulation is studied experimentally and simulated numerically in the case of parametric excitation of relaxation oscillations at the subharmonic of a modulating signal. Parametric processes are investigated by modulating the pump in two regimes of the SSRL operation: steady-state regime of unidirectional lasing and self-modulation regime of the first kind. Significant differences in the dynamics of radiation for these regimes are found. It is established that when the laser operates in the self-modulation regime, a first-order parametric instability can result in the appearance of the dynamic chaos regime. (control of laser radiation parameters)

  13. Design of tissue engineering scaffolds as delivery devices for mechanical and mechanically modulated signals.

    Science.gov (United States)

    Anderson, Eric J; Knothe Tate, Melissa L

    2007-10-01

    New approaches to tissue engineering aim to exploit endogenous strategies such as those occurring in prenatal development and recapitulated during postnatal healing. Defining tissue template specifications to mimic the environment of the condensed mesenchyme during development allows for exploitation of tissue scaffolds as delivery devices for extrinsic cues, including biochemical and mechanical signals, to drive the fate of mesenchymal stem cells seeded within. Although a variety of biochemical signals that modulate stem cell fate have been identified, the mechanical signals conducive to guiding pluripotent cells toward specific lineages are less well characterized. Furthermore, not only is spatial and temporal control of mechanical stimuli to cells challenging, but also tissue template geometries vary with time due to tissue ingrowth and/or scaffold degradation. Hence, a case study was carried out to analyze flow regimes in a testbed scaffold as a first step toward optimizing scaffold architecture. A pressure gradient was applied to produce local (nm-micron) flow fields conducive to migration, adhesion, proliferation, and differentiation of cells seeded within, as well as global flow parameters (micron-mm), including flow velocity and permeability, to enhance directed cell infiltration and augment mass transport. Iterative occlusion of flow channel dimensions was carried out to predict virtually the effect of temporal geometric variation (e.g., due to tissue development and growth) on delivery of local and global mechanical signals. Thereafter, insights from the case study were generalized to present an optimization scheme for future development of scaffolds to be implemented in vitro or in vivo. Although it is likely that manufacture and testing will be required to finalize design specifications, it is expected that the use of the rational design optimization will reduce the number of iterations required to determine final prototype geometries and flow

  14. Modulation of dopamine D(2) receptor signaling by actin-binding protein (ABP-280).

    Science.gov (United States)

    Li, M; Bermak, J C; Wang, Z W; Zhou, Q Y

    2000-03-01

    Proteins that bind to G protein-coupled receptors have recently been identified as regulators of receptor anchoring and signaling. In this study, actin-binding protein 280 (ABP-280), a widely expressed cytoskeleton-associated protein that plays an important role in regulating cell morphology and motility, was found to associate with the third cytoplasmic loop of dopamine D(2) receptors. The specificity of this interaction was originally identified in a yeast two-hybrid screen and confirmed by protein binding. The functional significance of the D(2) receptor-ABP-280 association was evaluated in human melanoma cells lacking ABP-280. D(2) receptor agonists were less potent in inhibiting forskolin-stimulated cAMP production in these cells. Maximal inhibitory responses of D(2) receptor activation were also reduced. Further yeast two-hybrid experiments showed that ABP-280 association is critically dependent on the carboxyl domain of the D(2) receptor third cytoplasmic loop, where there is a potential serine phosphorylation site (S358). Serine 358 was replaced with aspartic acid to mimic the effects of receptor phosphorylation. This mutant (D(2)S358D) displayed compromised binding to ABP-280 and coupling to adenylate cyclase. PKC activation also generated D(2) receptor signaling attenuation, but only in ABP-containing cells, suggesting a PKC regulatory role in D(2)-ABP association. A mechanism for these results may be derived from a role of ABP-280 in the clustering of D(2) receptors, as determined by immunocytochemical analysis in ABP-deficient and replete cells. Our results suggest a new molecular mechanism of modulating D(2) receptor signaling by cytoskeletal protein interaction.

  15. Rac1 modulates mammalian lung branching morphogenesis in part through canonical Wnt signaling.

    Science.gov (United States)

    Danopoulos, Soula; Krainock, Michael; Toubat, Omar; Thornton, Matthew; Grubbs, Brendan; Al Alam, Denise

    2016-12-01

    Lung branching morphogenesis relies on a number of factors, including proper epithelial cell proliferation and differentiation, cell polarity, and migration. Rac1, a small Rho GTPase, orchestrates a number of these cellular processes, including cell proliferation and differentiation, cellular alignment, and polarization. Furthermore, Rac1 modulates both noncanonical and canonical Wnt signaling, important pathways in lung branching morphogenesis. Culture of embryonic mouse lung explants in the presence of the Rac1 inhibitor (NSC23766) resulted in a dose-dependent decrease in branching. Increased cell death and BrdU uptake were notably seen in the mesenchyme, while no direct effect on the epithelium was observed. Moreover, vasculogenesis was impaired following Rac1 inhibition as shown by decreased Vegfa expression and impaired LacZ staining in Flk1-Lacz reporter mice. Rac1 inhibition decreased Fgf10 expression in conjunction with many of its associated factors. Moreover, using the reporter lines TOPGAL and Axin2-LacZ, there was an evident decrease in canonical Wnt signaling in the explants treated with the Rac1 inhibitor. Activation of canonical Wnt pathway using WNT3a or WNT7b only partially rescued the branching inhibition. Moreover, these results were validated on human explants, where Rac1 inhibition resulted in impaired branching and decreased AXIN2 and FGFR2b expression. We therefore conclude that Rac1 regulates lung branching morphogenesis, in part through canonical Wnt signaling. However, the exact mechanisms by which Rac1 interacts with canonical Wnt in human and mouse lung requires further investigation. Copyright © 2016 the American Physiological Society.

  16. Differential modulation of Beta-adrenergic receptor signaling by trace amine-associated receptor 1 agonists.

    Directory of Open Access Journals (Sweden)

    Gunnar Kleinau

    Full Text Available Trace amine-associated receptors (TAAR are rhodopsin-like G-protein-coupled receptors (GPCR. TAAR are involved in modulation of neuronal, cardiac and vascular functions and they are potentially linked with neurological disorders like schizophrenia and Parkinson's disease. Subtype TAAR1, the best characterized TAAR so far, is promiscuous for a wide set of ligands and is activated by trace amines tyramine (TYR, phenylethylamine (PEA, octopamine (OA, but also by thyronamines, dopamine, and psycho-active drugs. Unfortunately, effects of trace amines on signaling of the two homologous β-adrenergic receptors 1 (ADRB1 and 2 (ADRB2 have not been clarified yet in detail. We, therefore, tested TAAR1 agonists TYR, PEA and OA regarding their effects on ADRB1/2 signaling by co-stimulation studies. Surprisingly, trace amines TYR and PEA are partial allosteric antagonists at ADRB1/2, whereas OA is a partial orthosteric ADRB2-antagonist and ADRB1-agonist. To specify molecular reasons for TAAR1 ligand promiscuity and for observed differences in signaling effects on particular aminergic receptors we compared TAAR, tyramine (TAR octopamine (OAR, ADRB1/2 and dopamine receptors at the structural level. We found especially for TAAR1 that the remarkable ligand promiscuity is likely based on high amino acid similarity in the ligand-binding region compared with further aminergic receptors. On the other hand few TAAR specific properties in the ligand-binding site might determine differences in ligand-induced effects compared to ADRB1/2. Taken together, this study points to molecular details of TAAR1-ligand promiscuity and identified specific trace amines as allosteric or orthosteric ligands of particular β-adrenergic receptor subtypes.

  17. A cytosolic juxtamembrane interface modulates plexin A3 oligomerization and signal transduction.

    Directory of Open Access Journals (Sweden)

    Rachael Barton

    Full Text Available Plexins (plxns are transmembrane (TM receptors involved in the guidance of vascular, lymphatic vessel, and neuron growth as well as cancer metastasis. Plxn signaling results in cytosolic GTPase-activating protein activity, and previous research implicates dimerization as important for activation of plxn signaling. Purified, soluble plxn extracellular and cytosolic domains exhibit only weak homomeric interactions, suggesting a role for the plxn TM and juxtamembrane regions in homooligomerization. In this study, we consider a heptad repeat in the Danio rerio PlxnA3 cytosolic juxtamembrane domain (JM for its ability to influence PlxnA3 homooligomerization in TM-domain containing constructs. Site-directed mutagenesis in conjunction with the AraTM assay and bioluminescent energy transfer (BRET² suggest an interface involving a JM heptad repeat, in particular residue M1281, regulates PlxnA3 homomeric interactions when examined in constructs containing an ectodomain, TM and JM domain. In the presence of a neuropilin-2a co-receptor and semaphorin 3F ligand, disruption to PlxnA3 homodimerization caused by an M1281F mutation is eliminated, suggesting destabilization of the PlxnA3 homodimer in the JM is not sufficient to disrupt co-receptor complex formation. In contrast, enhanced homodimerization of PlxnA3 caused by mutation M1281L remains even in the presence of ligand semaphorin 3F and co-receptor neuropilin-2a. Consistent with this pattern of PlxnA3 dimerization in the presence of ligand and co-receptor, destabilizing mutations to PlxnA3 homodimerization (M1281F are able to rescue motor patterning defects in sidetracked zebrafish embryos, whereas mutations that enhance PlxnA3 homodimerization (M1281L are not. Collectively, our results indicate the JM heptad repeat, in particular residue M1281, forms a switchable interface that modulates both PlxnA3 homomeric interactions and signal transduction.

  18. Modulation of the beta-catenin signaling pathway by the dishevelled-associated protein Hipk1.

    Directory of Open Access Journals (Sweden)

    Sarah H Louie

    Full Text Available BACKGROUND: Wnts are evolutionarily conserved ligands that signal through beta-catenin-dependent and beta-catenin-independent pathways to regulate cell fate, proliferation, polarity, and movements during vertebrate development. Dishevelled (Dsh/Dvl is a multi-domain scaffold protein required for virtually all known Wnt signaling activities, raising interest in the identification and functions of Dsh-associated proteins. METHODOLOGY: We conducted a yeast-2-hybrid screen using an N-terminal fragment of Dsh, resulting in isolation of the Xenopus laevis ortholog of Hipk1. Interaction between the Dsh and Hipk1 proteins was confirmed by co-immunoprecipitation assays and mass spectrometry, and further experiments suggest that Hipk1 also complexes with the transcription factor Tcf3. Supporting a nuclear function during X. laevis development, Myc-tagged Hipk1 localizes primarily to the nucleus in animal cap explants, and the endogenous transcript is strongly expressed during gastrula and neurula stages. Experimental manipulations of Hipk1 levels indicate that Hipk1 can repress Wnt/beta-catenin target gene activation, as demonstrated by beta-catenin reporter assays in human embryonic kidney cells and by indicators of dorsal specification in X. laevis embryos at the late blastula stage. In addition, a subset of Wnt-responsive genes subsequently requires Hipk1 for activation in the involuting mesoderm during gastrulation. Moreover, either over-expression or knock-down of Hipk1 leads to perturbed convergent extension cell movements involved in both gastrulation and neural tube closure. CONCLUSIONS: These results suggest that Hipk1 contributes in a complex fashion to Dsh-dependent signaling activities during early vertebrate development. This includes regulating the transcription of Wnt/beta-catenin target genes in the nucleus, possibly in both repressive and activating ways under changing developmental contexts. This regulation is required to modulate gene

  19. Electronic polarization-division demultiplexing based on digital signal processing in intensity-modulation direct-detection optical communication systems.

    Science.gov (United States)

    Kikuchi, Kazuro

    2014-01-27

    We propose a novel configuration of optical receivers for intensity-modulation direct-detection (IM · DD) systems, which can cope with dual-polarization (DP) optical signals electrically. Using a Stokes analyzer and a newly-developed digital signal-processing (DSP) algorithm, we can achieve polarization tracking and demultiplexing in the digital domain after direct detection. Simulation results show that the power penalty stemming from digital polarization manipulations is negligibly small.

  20. A Delta-Sigma Modulator Using a Non-uniform Quantizer Adjusted for the Probability Density of Input Signals

    Science.gov (United States)

    Kitayabu, Toru; Hagiwara, Mao; Ishikawa, Hiroyasu; Shirai, Hiroshi

    A novel delta-sigma modulator that employs a non-uniform quantizer whose spacing is adjusted by reference to the statistical properties of the input signal is proposed. The proposed delta-sigma modulator has less quantization noise compared to the one that uses a uniform quantizer with the same number of output values. With respect to the quantizer on its own, Lloyd proposed a non-uniform quantizer that is best for minimizing the average quantization noise power. The applicable condition of the method is that the statistical properties of the input signal, the probability density, are given. However, the procedure cannot be directly applied to the quantizer in the delta-sigma modulator because it jeopardizes the modulator's stability. In this paper, a procedure is proposed that determine the spacing of the quantizer with avoiding instability. Simulation results show that the proposed method reduces quantization noise by up to 3.8dB and 2.8dB with the input signal having a PAPR of 16dB and 12dB, respectively, compared to the one employing a uniform quantizer. Two alternative types of probability density function (PDF) are used in the proposed method for the calculation of the output values. One is the PDF of the input signal to the delta-sigma modulator and the other is an approximated PDF of the input signal to the quantizer inside the delta-sigma modulator. Both approaches are evaluated to find that the latter gives lower quantization noise.

  1. Method to improve the signal-to-noise ratio of photon-counting chirped amplitude modulation ladar.

    Science.gov (United States)

    Zhang, Zijing; Wu, Long; Zhang, Yong; Zhao, Yuan

    2013-01-10

    Photon-counting chirped amplitude modulation (PCCAM) ladar employs Geiger mode avalanche photodiode as a detector. After the detector corresponding to the echo signal is reflected from an object or target, the modulation depth (MD) of the detection outputs has some certain loss relative to that of the transmitting signal. The signal-to-noise ratio (SNR) of PCCAM ladar is mainly determined by the MD of detection outputs of the echo signal. There is a proper echo signal intensity that can decrease the MD loss and improve the SNR of the ladar receiver. In this paper, an improved PCCAM ladar system is presented, which employs an echo signal intensity optimization strategy with an iris diaphragm under different signal and noise intensities. The improved system is demonstrated with the background noise of a sunny day and the echo signal intensity from 0.1 to 10 counts/ns. The experimental results show that it can effectively improve the SNR of the ladar receiver compared with the typical PCCAM ladar system. © 2013 Optical Society of America

  2. S-Nitrosothiols modulate G protein-coupled receptor signaling in a reversible and highly receptor-specific manner

    Directory of Open Access Journals (Sweden)

    Mönkkönen Kati S

    2005-04-01

    Full Text Available Abstract Background Recent studies indicate that the G protein-coupled receptor (GPCR signaling machinery can serve as a direct target of reactive oxygen species, including nitric oxide (NO and S-nitrosothiols (RSNOs. To gain a broader view into the way that receptor-dependent G protein activation – an early step in signal transduction – might be affected by RSNOs, we have studied several receptors coupling to the Gi family of G proteins in their native cellular environment using the powerful functional approach of [35S]GTPγS autoradiography with brain cryostat sections in combination with classical G protein activation assays. Results We demonstrate that RSNOs, like S-nitrosoglutathione (GSNO and S-nitrosocysteine (CysNO, can modulate GPCR signaling via reversible, thiol-sensitive mechanisms probably involving S-nitrosylation. RSNOs are capable of very targeted regulation, as they potentiate the signaling of some receptors (exemplified by the M2/M4 muscarinic cholinergic receptors, inhibit others (P2Y12 purinergic, LPA1lysophosphatidic acid, and cannabinoid CB1 receptors, but may only marginally affect signaling of others, such as adenosine A1, μ-opioid, and opiate related receptors. Amplification of M2/M4 muscarinic responses is explained by an accelerated rate of guanine nucleotide exchange, as well as an increased number of high-affinity [35S]GTPγS binding sites available for the agonist-activated receptor. GSNO amplified human M4 receptor signaling also under heterologous expression in CHO cells, but the effect diminished with increasing constitutive receptor activity. RSNOs markedly inhibited P2Y12 receptor signaling in native tissues (rat brain and human platelets, but failed to affect human P2Y12 receptor signaling under heterologous expression in CHO cells, indicating that the native cellular signaling partners, rather than the P2Y12 receptor protein, act as a molecular target for this action. Conclusion These in vitro studies

  3. 10 Gb/s 16-quadrature amplitude modulation signal delivery over a wireless fiber system by using a directly modulated laser for electrical/optical conversion

    Institute of Scientific and Technical Information of China (English)

    Lun Zhao; Jianguo Yu

    2015-01-01

    We propose and experimentally demonstrate a novel scheme to realize electrical/optical (E/O) conversion on the receiver side of a wireless fiber integration system at the W band.At the receiver,a directly modulated laser (DML) is used to realize E/O conversion.The received 85 GHz wireless millimeter-wave (mm-wave) signal is first down-converted into a 10 GHz electrical intermediate-frequency (IF) signal to overcome the insufficient bandwidth of the subsequent DML.Then,two cascaded electrical amplifiers (EAs) are employed to boost the electrical IF signal before it is used to drive a DML.By using this scheme,we transmit a 10 Gb/s 16 quadrature amplitude modulation (16QAM) signal over a 10 m wireless link,and then deliver it over a 2 km single-mode fiber-28 (SMF-28) wire link with a bit error ratio (BER) that is less than the hard-decision forward error correction threshold of 3.8 × 10-3.Our experimental results show that the DML is good device to be used for the E/O conversion of a 16QAM signal.

  4. Demonstration of 48-Gb/s 16-QAM signal transmission using half cycle sub-carrier modulation in intensity modulation/direct detection system

    Science.gov (United States)

    Tang, Jin; He, Jing; Chen, Ming; Li, Danyu; Chen, Lin

    2015-01-01

    A simple spectral-efficiency intensity modulation/direct detection (IM/DD) system based on half cycle sub-carrier modulation (SCM) signal is proposed for short reach fiber communications in this paper. The signal impairment of frequency selective fading due to fiber chromatics dispersion (CD) is mathematically analyzed. To reduce the performance deterioration caused by the non-flat transfer function, digital pre- and post-equalization is applied in the system. The peak to average power ratio (PAPR) of the signal is also discussed in comparison with that of orthogonal frequency division multiplexing (OFDM). The transmission of 16-QAM half cycle SCM signal with a sub-carrier frequency of half the symbol rate and Nyquist pulse shaping is experimentally demonstrated. The bit-error rate (BER) of 48 Gb/s polarization multiplexing division (PDM) 16 QAM half cycle SCM signal is less than 7% forward-error-correction (FEC) threshold of 3.8 ×10-3 after transmission over 83 km standard single-mode fiber (SSMF).

  5. Capacity-Approaching Modulation Formats for Optical Transmission Systems: Signal shaping and advanced de/muxing for efficient resource exploitation

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel

    Aiming for efficient fiber-optic data transport, this thesis addresses three scenario-specific modulation and/or multiplexing techniques which, leveraging digital signal processing, can further exploit the available resources.The considered environments are: (i) (ultra) long-haul networks, where ...

  6. Tone Modulation in a Passive OTDM Multiplexer for Clock Recovery from a 160 Gbit/s OTDM Signal

    Institute of Scientific and Technical Information of China (English)

    Tetsuya.; Miyazaki; Fumito; Kubota

    2003-01-01

    Tone modulation in a passive OTDM multiplexer for clock recovery from a 160-Gbit/s OTDM signal by using a base-rate receiver is demonstrated. We performed synchronous demultiplexing in back-to-back arrangement and optical sampling after 320-km transmission.

  7. Experimental Investigation of WDM transmission properties for optical labeled signals using orthogonal IM/FSK modulation format

    DEFF Research Database (Denmark)

    Holm-Nielsen, Pablo Villanueva; Zhang, Jianfeng; Olmos, J. J. Vegas

    2004-01-01

    In this paper we report on WDM transmission of optical labeled signals using the orthogonal IM/FSK modulation format aimed for optical packet/burst switching. WDM transmission in both a point-to-point transmission system and a demonstration network with a label-swapping node are implemented....

  8. Saturation Effect on Pump-to-Signal Intensity Modulation Transfer in Single-Pump Phase-Insensitive Fibre Optic Parametric Amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke

    2011-01-01

    A numerical and experimental characterization of how signal gain saturation affects the transfer of the intensity modulation of the pump to the signal in single-pump phaseinsensitive fibre optic parametric amplifiers is presented.......A numerical and experimental characterization of how signal gain saturation affects the transfer of the intensity modulation of the pump to the signal in single-pump phaseinsensitive fibre optic parametric amplifiers is presented....

  9. Design, parametrization, and pole placement of stabilizing output feedback compensators via injective cogenerator quotient signal modules.

    Science.gov (United States)

    Blumthaler, Ingrid; Oberst, Ulrich

    2012-03-01

    Control design belongs to the most important and difficult tasks of control engineering and has therefore been treated by many prominent researchers and in many textbooks, the systems being generally described by their transfer matrices or by Rosenbrock equations and more recently also as behaviors. Our approach to controller design uses, in addition to the ideas of our predecessors on coprime factorizations of transfer matrices and on the parametrization of stabilizing compensators, a new mathematical technique which enables simpler design and also new theorems in spite of the many outstanding results of the literature: (1) We use an injective cogenerator signal module ℱ over the polynomial algebra [Formula: see text] (F an infinite field), a saturated multiplicatively closed set T of stable polynomials and its quotient ring [Formula: see text] of stable rational functions. This enables the simultaneous treatment of continuous and discrete systems and of all notions of stability, called T-stability. We investigate stabilizing control design by output feedback of input/output (IO) behaviors and study the full feedback IO behavior, especially its autonomous part and not only its transfer matrix. (2) The new technique is characterized by the permanent application of the injective cogenerator quotient signal module [Formula: see text] and of quotient behaviors [Formula: see text] of [Formula: see text]-behaviors B. (3) For the control tasks of tracking, disturbance rejection, model matching, and decoupling and not necessarily proper plants we derive necessary and sufficient conditions for the existence of proper stabilizing compensators with proper and stable closed loop behaviors, parametrize all such compensators as IO behaviors and not only their transfer matrices and give new algorithms for their construction. Moreover we solve the problem of pole placement or spectral assignability for the complete feedback behavior. The properness of the full feedback behavior

  10. Optogenetic Module for Dichromatic Control of c-di-GMP Signaling.

    Science.gov (United States)

    Ryu, Min-Hyung; Fomicheva, Anastasia; Moskvin, Oleg V; Gomelsky, Mark

    2017-09-15

    Many aspects of bacterial physiology and behavior, including motility, surface attachment, and the cell cycle, are controlled by cyclic di-GMP (c-di-GMP)-dependent signaling pathways on the scale of seconds to minutes. Interrogation of such processes in real time requires tools for introducing rapid and reversible changes in intracellular c-di-GMP levels. Inducing the expression of genes encoding c-di-GMP-synthetic (diguanylate cyclases) and -degrading (c-di-GMP phosphodiesterase) enzymes by chemicals may not provide adequate temporal control. In contrast, light-controlled diguanylate cyclases and phosphodiesterases can be quickly activated and inactivated. A red/near-infrared-light-regulated diguanylate cyclase, BphS, was engineered previously, yet a complementary light-activated c-di-GMP phosphodiesterase has been lacking. In search of such a phosphodiesterase, we investigated two homologous proteins from Allochromatium vinosum and Magnetococcus marinus, designated BldP, which contain C-terminal EAL-BLUF modules, where EAL is a c-di-GMP phosphodiesterase domain and BLUF is a blue light sensory domain. Characterization of the BldP proteins in Escherichia coli and in vitro showed that they possess light-activated c-di-GMP phosphodiesterase activities. Interestingly, light activation in both enzymes was dependent on oxygen levels. The truncated EAL-BLUF fragment from A. vinosum BldP lacked phosphodiesterase activity, whereas a similar fragment from M. marinus BldP, designated EB1, possessed such activity that was highly (>30-fold) upregulated by light. Following light withdrawal, EB1 reverted to the inactive ground state with a half-life of ∼6 min. Therefore, the blue-light-activated phosphodiesterase EB1 can be used in combination with the red/near-infrared-light-regulated diguanylate cyclase BphS for the bidirectional regulation of c-di-GMP-dependent processes in E. coli as well as other bacterial and nonbacterial cells.IMPORTANCE Regulation of motility

  11. In-band 16-QAM and multi-carrier SCM modulation to label DPSK payload signals for IP packet routing.

    Science.gov (United States)

    Tafur Monroy, Idelfonso; Vegas Olmos, Juan; Garcia Larrode, Maria; Koonen, Ton; Díaz Jiménez, Cristina

    2006-02-06

    We present an experimental demonstration of the feasibility of in-band subcarrier multiplexing (SCM) for labeling of differential phase shift keying (DPSK) payload signals. We show that by proper selection of the value of the subcarrier frequency the effect of the superimposed SCM label on the performance of the DPSK signal is minimized. Furthermore, we show experimentally the advantages of using alternative modulation formats such as 16-QAM and multi-carrier SCM for optical labeling of a 10 Gb/s DPSK payload signal.

  12. In-band 16-QAM and multi-carrier SCM modulation to label DPSK payload signals for IP packet routing

    Science.gov (United States)

    Tafur Monroy, Idelfonso; Vegas Olmos, Juan; Garcia Larrode, Maria; Koonen, Ton; Díaz Jiménez, Cristina

    2006-02-01

    We present an experimental demonstration of the feasibility of in-band subcarrier multiplexing (SCM) for labeling of differential phase shift keying (DPSK) payload signals. We show that by proper selection of the value of the subcarrier frequency the effect of the superimposed SCM label on the performance of the DPSK signal is minimized. Furthermore, we show experimentally the advantages of using alternative modulation formats such as 16-QAM and multi-carrier SCM for optical labeling of a 10 Gb/s DPSK payload signal.

  13. Stochastic resonance in a single-mode laser driven by quadratic Pump noise and amplitude-modulated signal

    Institute of Scientific and Technical Information of China (English)

    Zhang Li

    2009-01-01

    This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by quadratic pump noise and amplitude-modulated signal.A new linear approximation approach is advanced to calculate the signal-to-noise ratio.In the linear approximation only the drift term is linearized,the multiplicative noise term is unchangeable.It is found that there appears not only the standard form of stochastic resonance but also the broad sense of stochastic resonance,especially stochastic multiresonance appears in the curve of signal-to-noise ratio as a function of coupling strength λ between the real and imaginary parts of the pump noise.

  14. Modulation of SIV and HIV DNA Vaccine Immunity by Fas-FasL Signaling

    Directory of Open Access Journals (Sweden)

    Jiabin Yan

    2015-03-01

    Full Text Available Signaling through the Fas/Apo-1/CD95 death receptor is known to affect virus-specific cell-mediated immune (CMI responses. We tested whether modulating the Fas-apoptotic pathway can enhance immune responses to DNA vaccination or lymphocytic choriomeningitis virus (LCMV infection. Mice were electroporated with plasmids expressing a variety of pro- or anti-apoptotic molecules related to Fas signaling and then either LCMV-infected or injected with plasmid DNA expressing SIV or HIV antigens. Whereas Fas or FasL knockout mice had improved CMI, down-regulation of Fas or FasL by shRNA or antibody failed to improve CMI and was accompanied by increases in regulatory T cells (Treg. Two “adjuvant” plasmids were discovered that significantly enhanced plasmid immunizations. The adjuvant effects of Fas-associated death domain (FADD and of cellular FLICE-inhibitory protein (cFLIP were consistently accompanied by increased effector memory T lymphocytes and increased T cell proliferation. This adjuvant effect was also observed when comparing murine infections with LCMV-Armstrong and its persisting variant LCMV-Clone 13. LCMV-Armstrong was cleared in 100% of mice nine days after infection, while LCMV-Clone 13 persisted in all mice. However, half of the mice pre-electroporated with FADD or cFLIP plasmids were able to clear LCMV-Clone 13 by day nine, and, in the case of cFLIP, increased viral clearance was accompanied by higher CMI. Our studies imply that molecules in the Fas pathway are likely to affect a number of events in addition to the apoptosis of cells involved in immunity.

  15. N-cadherin promotes thyroid tumorigenesis through modulating major signaling pathways.

    Science.gov (United States)

    Da, Chenxing; Wu, Kexia; Yue, Chenli; Bai, Peisong; Wang, Rong; Wang, Guanjie; Zhao, Man; Lv, Yanyan; Hou, Peng

    2017-01-31

    Epithelial-mesenchymal transition (EMT), a crucial step in disease progression, plays a key role in tumor metastasis. N-cadherin, a well-known EMT marker, acts as a major oncogene in diverse cancers, whereas its functions in thyroid cancer remains largely unclear. This study was designed to explore the biological roles and related molecular mechanism of N-cadherin in thyroid tumorigenesis. Quantitative RT-PCR (qRT-PCR) and immunohistochemistry assays were used to evaluate N-cadherin expression. A series of in vitro studies such as cell proliferation, colony formation, cell cycle, apoptosis, migration and invasion assays were performed to determine the effect of N-cadherin on malignant behavior of thyroid cancer cells. Our results showed that N-cadherin was significantly upregulated in papillary thyroid cancers (PTCs) as compared with non-cancerous thyroid tissues. N-cadherin knockdown markedly inhibited cell proliferation, colony formation, cell migration and invasion, and induced cell cycle arrest and apoptosis. On the other hand, ectopic expression of N-cadherin promoted thyroid cancer cell growth and invasiveness. Mechanically, our data demonstrated that tumor-promoting role of N-cadherin in thyroid cancer was closely related to the activities of the MAPK/Erk, the phosphatidylinositol-3-kinase (PI3K)/Akt and p16/Rb signaling pathways in addition to affecting the EMT process. Altogether, our findings suggest that N-cadherin promotes thyroid tumorigenesis by modulating the activities of major signaling pathways and EMT process, and may represent a potential therapeutic target for this cancer.

  16. Extract of Reishi polysaccharides induces cytokine expression via TLR4-modulated protein kinase signaling pathways.

    Science.gov (United States)

    Hsu, Hsien-Yeh; Hua, Kuo-Feng; Lin, Chun-Cheng; Lin, Chun-Hung; Hsu, Jason; Wong, Chi-Huey

    2004-11-15

    We have demonstrated that an extract of Ganoderma lucidum (Reishi or Ling-Zhi) polysaccharides (EORP) exerts immunomodulating activities by stimulating the expression of inflammatory cytokines from mouse spleen cells. Interestingly, via responding to LPS in genetic variation of murine macrophage HeNC2 and GG2EE cell lines, and using TLR4 Ab blockage in human blood-derived monocytic macrophages, we have found that the TLR4, but not complement receptor type 3, is a putative receptor of EORP, mediating the consequent immunomodulating events associated with IL-1 gene expression. Based on our studies of reactive oxygen species production, polymyxin B inhibition, and protein tyrosine kinase (PTK) activity, we ruled out the possibility of LPS contamination in EORP. We have found that EORP differentially modulates the protein kinase (PK)-mediated signal transduction pathways associated with inflammatory cytokine IL-1. In human macrophages and murine macrophage J774A.1 cells, EORP was found to up-regulate IL-1 secretion and pro-IL-1 (precursor of IL-1) as well as IL-1-converting enzyme expression. Specifically, EORP rapidly stimulates PTK-mediated phosphorylation, followed by induction of PKs and activation of MAPKs: ERK, JNK, and p38. Using PK inhibitors in the kinase activity assays, Western blot analyses and IL-1 ELISA, we have extensively examined and dissected the role of individual PK in the regulation of pro-IL-1/IL-1. Our findings establish that EORP-mediated signaling pathways are involved in the pro-IL-1/IL-1 regulation: PTK/protein kinase C/MEK1/ERK and PTK/Rac1/p21-activated kinase/p38.

  17. Histamine derived from probiotic Lactobacillus reuteri suppresses TNF via modulation of PKA and ERK signaling.

    Directory of Open Access Journals (Sweden)

    Carissa M Thomas

    Full Text Available Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA, histidine/histamine antiporter (hdcP, and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H(2 receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases.

  18. Pedilanthus tithymaloides Inhibits HSV Infection by Modulating NF-κB Signaling.

    Directory of Open Access Journals (Sweden)

    Durbadal Ojha

    Full Text Available Pedilanthus tithymaloides (PT, a widely used ethnomedicinal plant, has been employed to treat a number of skin conditions. To extend its utility and to fully exploit its medicinal potential, we have evaluated the in vitro antiviral activity of a methanolic extract of PT leaves and its isolated compounds against Herpes Simplex Virus type 2 (HSV-2. Bioactivity-guided studies revealed that the extract and one of its constituents, luteolin, had potent antiviral activity against wild-type and clinical isolates of HSV-2 (EC50 48.5-52.6 and 22.4-27.5 μg/ml, respectively, with nearly complete inhibition at 86.5-101.8 and 40.2-49.6 μg/ml, respectively. The inhibitory effect was significant (p<0.001 when the drug was added 2 h prior to infection, and was effective up to 4 h post-infection. As viral replication requires NF-κB activation, we examined whether the observed extract-induced inhibition of HSV-2 was related to NF-κB inhibition. Interestingly, we observed that treatment of HSV-2-infected cells with extract or luteolin suppressed NF-κB activation. Although NF-κB, JNK and MAPK activation was compromised during HSV replication, neither the extract nor luteolin affected HSV-2-induced JNK1/2 and MAPK activation. Moreover, the PT leaf extract and luteolin potently down-regulated the expression of tumor necrosis factor (TNF-α, Interleukin (IL-1β, IL-6, NO and iNOS and the production of gamma interferon (IFN-γ, which are directly involved in controlling the NF-κB signaling pathway. Thus, our results indicate that both PT leaf extract and luteolin modulate the NF-κB signaling pathway, resulting in the inhibition of HSV-2 replication.

  19. C. elegans VANG-1 modulates life span via insulin/IGF-1-like signaling.

    Directory of Open Access Journals (Sweden)

    Sebastian J Honnen

    Full Text Available The planar cell polarity (PCP pathway is highly conserved from Drosophila to humans and a PCP-like pathway has recently been described in the nematode Caenorhabditis elegans. The developmental function of this pathway is to coordinate the orientation of cells or structures within the plane of an epithelium or to organize cell-cell intercalation required for correct morphogenesis. Here, we describe a novel role of VANG-1, the only C. elegans ortholog of the conserved PCP component Strabismus/Van Gogh. We show that two alleles of vang-1 and depletion of the protein by RNAi cause an increase of mean life span up to 40%. Consistent with the longevity phenotype vang-1 animals also show enhanced resistance to thermal- and oxidative stress and decreased lipofuscin accumulation. In addition, vang-1 mutants show defects like reduced brood size, decreased ovulation rate and prolonged reproductive span, which are also related to gerontogenes. The germline, but not the intestine or neurons, seems to be the primary site of vang-1 function. Life span extension in vang-1 mutants depends on the insulin/IGF-1-like receptor DAF-2 and DAF-16/FoxO transcription factor. RNAi against the phase II detoxification transcription factor SKN-1/Nrf2 also reduced vang-1 life span that might be explained by gradual inhibition of insulin/IGF-1-like signaling in vang-1. This is the first time that a key player of the PCP pathway is shown to be involved in the insulin/IGF-1-like signaling dependent modulation of life span in C. elegans.

  20. Sema4C-Plexin B2 signalling modulates ureteric branching in developing kidney.

    Science.gov (United States)

    Perälä, Nina; Jakobson, Madis; Ola, Roxana; Fazzari, Pietro; Penachioni, Junia Y; Nymark, Mariann; Tanninen, Tiina; Immonen, Tiina; Tamagnone, Luca; Sariola, Hannu

    2011-02-01

    Semaphorins, originally identified as axon guidance molecules, have also been implicated in angiogenesis, function of the immune system and cancerous growth. Here we show that deletion of Plexin B2 (Plxnb2), a semaphorin receptor that is expressed both in the pretubular aggregates and the ureteric epithelium in the developing kidney, results in renal hypoplasia and occasional double ureters. The rate of cell proliferation in the ureteric epithelium and consequently the number of ureteric tips are reduced in the kidneys lacking Plexin B2 (Plxnb2-/-). Semaphorin 4C, a ligand for Plexin B2, stimulates branching of the ureteric epithelium in wild type and Plxnb2+/- kidney explants, but not in Plxnb2-/- explants. As shown by co-immunoprecipitation Plexin B2 interacts with the Ret receptor tyrosine kinase, the receptor of Glial-cell-line-derived neurotrophic factor (Gdnf), in embryonic kidneys. Isolated Plxnb2-/- ureteric buds fail to respond to Gdnf by branching, but this response is rescued by Fibroblast growth factor 7 and Follistatin as well as by the metanephric mesenchyme. The differentiation of the nephrogenic mesenchyme, its morphology and the rate of apoptosis in the Plxnb2-/- kidneys are normal. Plexin B2 is co-expressed with Plexin B1 (Plxnb1) in the kidney. The double homozygous Plxnb1-Plxnb2-deficient mice show high embryonic lethality prior to onset of nephrogenesis. The only double homozygous embryo surviving to E12 showed hypoplastic kidneys with ureteric branches and differentiating mesenchyme. Taken together, our results show that Sema4C-Plexin B2 signalling regulates ureteric branching, possibly through modulation of Gdnf signalling by interaction with Ret, and suggest non-redundant roles for Plexin B1 and Plexin B2 in kidney development. Copyright © 2010 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  1. A calcium sensor - protein kinase signaling module diversified in plants and is retained in all lineages of Bikonta species.

    Science.gov (United States)

    Beckmann, Linda; Edel, Kai H; Batistič, Oliver; Kudla, Jörg

    2016-08-19

    Calcium (Ca(2+)) signaling is a universal mechanism of signal transduction and involves Ca(2+) signal formation and decoding of information by Ca(2+) binding proteins. Calcineurin B-like proteins (CBLs), which upon Ca(2+) binding activate CBL-interacting protein kinases (CIPKs) regulate a multitude of physiological processes in plants. Here, we combine phylogenomics and functional analyses to investigate the occurrence and structural conservation of CBL and CIPK proteins in 26 species representing all major clades of eukaryotes. We demonstrate the presence of at least singular CBL-CIPK pairs in representatives of Archaeplastida, Chromalveolates and Excavates and their general absence in Opisthokonta and Amoebozoa. This denotes CBL-CIPK complexes as evolutionary ancient Ca(2+) signaling modules that likely evolved in the ancestor of all Bikonta. Furthermore, we functionally characterize the CBLs and CIPK from the parabasalid human pathogen Trichomonas vaginalis. Our results reveal strict evolutionary conservation of functionally important structural features, preservation of biochemical properties and a remarkable cross-kingdom protein-protein interaction potential between CBLs and CIPKs from Arabidopsis thaliana and T. vaginalis. Together our findings suggest an ancient evolutionary origin of a functional CBL-CIPK signaling module close to the root of eukaryotic evolution and provide insights into the initial evolution of signaling networks and Ca(2+) signaling specificity.

  2. A calcium sensor – protein kinase signaling module diversified in plants and is retained in all lineages of Bikonta species

    Science.gov (United States)

    Beckmann, Linda; Edel, Kai H.; Batistič, Oliver; Kudla, Jörg

    2016-01-01

    Calcium (Ca2+) signaling is a universal mechanism of signal transduction and involves Ca2+ signal formation and decoding of information by Ca2+ binding proteins. Calcineurin B-like proteins (CBLs), which upon Ca2+ binding activate CBL-interacting protein kinases (CIPKs) regulate a multitude of physiological processes in plants. Here, we combine phylogenomics and functional analyses to investigate the occurrence and structural conservation of CBL and CIPK proteins in 26 species representing all major clades of eukaryotes. We demonstrate the presence of at least singular CBL-CIPK pairs in representatives of Archaeplastida, Chromalveolates and Excavates and their general absence in Opisthokonta and Amoebozoa. This denotes CBL-CIPK complexes as evolutionary ancient Ca2+ signaling modules that likely evolved in the ancestor of all Bikonta. Furthermore, we functionally characterize the CBLs and CIPK from the parabasalid human pathogen Trichomonas vaginalis. Our results reveal strict evolutionary conservation of functionally important structural features, preservation of biochemical properties and a remarkable cross-kingdom protein-protein interaction potential between CBLs and CIPKs from Arabidopsis thaliana and T. vaginalis. Together our findings suggest an ancient evolutionary origin of a functional CBL-CIPK signaling module close to the root of eukaryotic evolution and provide insights into the initial evolution of signaling networks and Ca2+ signaling specificity. PMID:27538881

  3. Digital Receiver-based Electronic Intelligence System Configuration for the Detection and Identification of Intrapulse Modulated Radar Signals

    Directory of Open Access Journals (Sweden)

    A. K. Singh

    2014-03-01

    Full Text Available An optimum electronic intelligence system configuration incorporating the state of the art technologies and achieving the highest parameter accuracies while processing the complex intrapulse modulated radar signals is presented in this paper. The system is based on the quad digital receiver, a state of the art single board solution for the detection and analysis of modern radar signals. The system consists of base line interferometry  configuration for high accuracy direction finding measurement with sector selection based on amplitude direction finding technique. Advanced signal processing algorithms with time frequency analysis are implemented in real time in field programmable gate array to extract all the basic as well as advanced parameters of frequency and phase modulations such as chirp, barker, and poly-phase (Frank, P1-P4 codes in addition to the pulse and continuous wave signals. The intercepted intrapulse modulated signal parameters have been extracted with very high accuracy and sensitivity.Defence Science Journal, 2014, 64(2, pp. 152-158. DOI: http://dx.doi.org/10.14429/dsj.64.5091

  4. Complex linear minimum mean-squared-error equalization of spatially quadrature-amplitude-modulated signals in holographic data storage

    Science.gov (United States)

    Sato, Takanori; Kanno, Kazutaka; Bunsen, Masatoshi

    2016-09-01

    We applied complex linear minimum mean-squared-error equalization to spatially quadrature-amplitude-modulated signals in holographic data storage (HDS). The equalization technique can improve dispersion in constellation outputs due to intersymbol interference. We confirm the effectiveness of the equalization technique in numerical simulations and basic optical experiments. Our numerical results have shown that intersymbol interference of a retrieved signal in a HDS system can be improved by using the equalization technique. In our experiments, a mean squared error (MSE), which indicates the deviation from an ideal signal, has been used for quantitatively evaluating the dispersion of equalized signals. Our equalization technique has been able to improve the MSE. However, symbols in the equalized signal have remained inseparable. To further improve the MSE and make the symbols separable, reducing errors in repeated measurements is our future task.

  5. Wheat bran feruloyl oligosaccharides modulate the phase II detoxifying/antioxidant enzymes via Nrf2 signaling.

    Science.gov (United States)

    Zhang, Huijuan; Wang, Jing; Liu, Yingli; Sun, Baoguo

    2015-03-01

    The antioxidant activities of wheat bran feruloyl oligosaccharides (FOs) were determined in rats by determining the activities and mRNA expression levels of phase II detoxifying/antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and heme oxygenase-1 (HO-1) in rat organs. FOs was given by gavage at doses of 0.25, 0.5, and 0.75 mmol/kg body weight every day for 15 days. Compared with the control group, the activities of SOD, CAT, and GSH-Px in FOs treatment groups significantly (Plevels of SOD, CAT, and HO-1 in organs. Moreover, the immunoblot analysis revealed increased nuclear factor-E2-related factor (Nrf2) protein expression levels in organs and there were positive correlations between the mRNA expression of phase II detoxifying/antioxidant enzymes and the expressions of Nrf2 protein, which demonstrated FOs treatment could modulate the detoxifying/antioxidant enzymes via Nrf2 signaling. Copyright © 2014. Published by Elsevier B.V.

  6. The Potential Role of Cannabinoids in Modulating Serotonergic Signaling by Their Influence on Tryptophan Metabolism

    Directory of Open Access Journals (Sweden)

    Dietmar Fuchs

    2010-08-01

    Full Text Available Phytocannabinoids present in Cannabis plants are well known to exert potent anti-inflammatory and immunomodulatory effects. Previously, we have demonstrated that the psychoactive D9-tetrahydrocannabinol (THC and the non-psychotropic cannabidiol (CBD modulate mitogen-induced Th1-type immune responses in peripheral blood mononuclear cells (PBMC. The suppressive effect of both cannabinoids on mitogen-induced tryptophan degradation mediated by indoleamine-2,3-dioxygenase (IDO, suggests an additional mechanism by which antidepressive effects of cannabinoids might be linked to the serotonergic system. Here, we will review the role of tryptophan metabolism in the course of cell mediated immune responses and the relevance of cannabinoids in serotonergic signaling. We conclude that in particular the non-psychotropic CBD might be useful for the treatment of mood disorders in patients with inflammatory diseases, since this cannabinoid seems to be safe and its effects on activation-induced tryptophan degradation by CBD were more potent as compared to THC.

  7. The chemopreventive bioflavonoid apigenin modulates signal transduction pathways in keratinocyte and colon carcinoma cell lines.

    Science.gov (United States)

    Van Dross, Rukiyah; Xue, Yue; Knudson, Alexandra; Pelling, Jill C

    2003-11-01

    Apigenin is a nonmutagenic chemopreventive agent found in fruits and green vegetables. In this study, we used two different epithelial cell lines (308 mouse keratinocytes and HCT116 colon carcinoma cells) to determine the effect of apigenin on the mitogen-activated protein kinase (MAPK) cascade. Apigenin induced a dose-dependent phosphorylation of both extracellular signal-regulated protein kinase (ERK) and p38 kinase but had little effect on the phosphorylation of c-jun amino terminal kinase (JNK). We used immunoprecipitation-coupled kinase assays to show that apigenin increased the kinase activity of ERK and p38 but not JNK. Consistent with these results, we found that apigenin induced a 7.4-fold induction in the phosphorylation of Elk, the downstream phosphorylation target of ERK kinase. Similarly, apigenin induced a 3.2-fold induction in the phosphorylation of activating transcription factor-2, the downstream phosphorylation target of p38 kinase. Little change was observed in the phosphorylation of c-jun, the phosphorylation target of JNK. These data suggest that part of the chemopreventive activity of apigenin may be mediated by its ability to modulate the MAPK cascade.

  8. Role of adipokines signaling in the modulation of T cells function

    Directory of Open Access Journals (Sweden)

    Claudio eProcaccini

    2013-10-01

    Full Text Available The field that links immunity and metabolism is rapidly expanding. Apparently non-immunological disorders such as obesity and type 2 diabetes have been linked to immune dysregulation, suggesting that metabolic alterations can be induced by or be consequence of an altered self-immune tolerance. In this context, adipose tissue produces and releases a variety of proinflammatory and anti-inflammatory factors, termed adipokines, which can be considered as the bridge between obesity-related exogenous factors, such as nutrition and lifestyle, and the molecular events leading to metabolic syndrome, inflammatory and/or autoimmune conditions. In obesity, increased production of most adipokines impacts on multiple functions such as appetite and energy balance, modulation of immune responses, insulin sensitivity, angiogenesis, blood pressure, lipid metabolism, and so on. This report aims to discuss some of the recent topics of adipocytokine research and their related signaling pathways, that may be of particular importance as could lead to effective therapeutic strategies for obesity-associated diseases.

  9. Signal transducer and activator of transcription 5B (STAT5B) modulates adipocyte differentiation via MOF.

    Science.gov (United States)

    Gao, Peng; Zhang, Yuchao; Liu, Yuantao; Chen, Jicui; Zong, Chen; Yu, Cong; Cui, Shang; Gao, Weina; Qin, Dandan; Sun, Wenchuan; Li, Xia; Wang, Xiangdong

    2015-12-01

    The role and mechanism of signal transducer and activator of transcription 5B (STAT5B) in adipogenesis remain unclear. In this study, our data showed that Males absent on the first (MOF) protein expression was increased during 3 T3-L1 preadipocytes differentiation accompanied with STAT5B expression increasing. Over-expression STAT5B enhanced MOF promoter trans-activation in HeLa cells. Mutagenesis assay and ChIP analysis exhibited that STAT5B was able to bind MOF promoter. Knocking-down STAT5B in 3 T3-L1 preadipocytes led to decreased expression of MOF, but resulted in increased expression of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα) and fatty acid-binding protein 4 (Fabp4), which were important factors or enzymes for adipogenesis. We also found that knocking-down MOF in 3 T3-L1 preadipocytes resulted in increased expression of PPARγ, C/EBPα and Fabp4, which was in the same trend as STAT5B knocking-down. Over-expression MOF resulted in reduced promoter trans-activation activity of C/EBPα. These results suggest that STAT5B and MOF work as negative regulators in adipogenesis, and STAT5B modulates preadipocytes differentiation partially by regulating MOF expression.

  10. Social discounting involves modulation of neural value signals by temporoparietal junction.

    Science.gov (United States)

    Strombach, Tina; Weber, Bernd; Hangebrauk, Zsofia; Kenning, Peter; Karipidis, Iliana I; Tobler, Philippe N; Kalenscher, Tobias

    2015-02-03

    Most people are generous, but not toward everyone alike: generosity usually declines with social distance between individuals, a phenomenon called social discounting. Despite the pervasiveness of social discounting, social distance between actors has been surprisingly neglected in economic theory and neuroscientific research. We used functional magnetic resonance imaging (fMRI) to study the neural basis of this process to understand the neural underpinnings of social decision making. Participants chose between selfish and generous alternatives, yielding either a large reward for the participant alone, or smaller rewards for the participant and another individual at a particular social distance. We found that generous choices engaged the temporoparietal junction (TPJ). In particular, the TPJ activity was scaled to the social-distance-dependent conflict between selfish and generous motives during prosocial choice, consistent with ideas that the TPJ promotes generosity by facilitating overcoming egoism bias. Based on functional coupling data, we propose and provide evidence for a biologically plausible neural model according to which the TPJ supports social discounting by modulating basic neural value signals in the ventromedial prefrontal cortex to incorporate social-distance-dependent other-regarding preferences into an otherwise exclusively own-reward value representation.

  11. Modulation of Apoptotic Signaling by the Hepatitis B Virus X Protein

    Directory of Open Access Journals (Sweden)

    Michael J. Bouchard

    2012-11-01

    Full Text Available Worldwide, an estimated 350 million people are chronically infected with the Hepatitis B Virus (HBV; chronic infection with HBV is associated with the development of severe liver diseases including hepatitis and cirrhosis. Individuals who are chronically infected with HBV also have a significantly higher risk of developing hepatocellular carcinoma (HCC than uninfected individuals. The HBV X protein (HBx is a key regulatory HBV protein that is important for HBV replication, and likely plays a cofactor role in the development of HCC in chronically HBV-infected individuals. Although some of the functions of HBx that may contribute to the development of HCC have been characterized, many HBx activities, and their putative roles during the development of HBV-associated HCC, remain incompletely understood. HBx is a multifunctional protein that localizes to the cytoplasm, nucleus, and mitochondria of HBV‑infected hepatocytes. HBx regulates numerous cellular signal transduction pathways and transcription factors as well as cell cycle progression and apoptosis. In this review, we will summarize reports in which the impact of HBx expression on cellular apoptotic pathways has been analyzed. Although various effects of HBx on apoptotic pathways have been observed in different model systems, studies of HBx activities in biologically relevant hepatocyte systems have begun to clarify apoptotic effects of HBx and suggest mechanisms that could link HBx modulation of apoptotic pathways to the development of HBV-associated HCC.

  12. Putrescine as a signal to modulate the indispensable ABA increase under cold stress

    Science.gov (United States)

    Cuevas, Juan C; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F

    2009-01-01

    Polyamines have been found to correlate frequently with biotic and abiotic insults, and their functional involvement in the plant responses to several stresses has been shown genetically with both gain and loss of function mutations. In spite of a large body of physiological and genetic data, the mode of action for polyamines at the molecular level still remains elusive. We have recently performed a detailed integrated analysis of polyamine metabolism under cold stress by means of metabolic studies, quantitative gene expression analyses, and gene inactivations, to characterize in more detail the role of polyamines in response to low temperature. Our data show a unique accumulation profile for putrescine compared to other polyamines, with a progressive increase upon cold stress treatment coincident with a similar transcriptional upregulation for the two arginine decarboxylase genes ADC1 and ADC2. Loss of function mutants adc1 and adc2 display reduced freezing tolerance and alterations in ABA content and ABA-dependent signalling pathways under low temperature, compared to wild type plants. Phenotypical reverse complementation tests for both adc and ABA-defective mutants support our conclusion that putrescine modulates ABA biosynthesis at the transcriptional level in response to low temperature thus uncovering a novel mode of action for polyamines as regulators of hormone biosynthesis. PMID:19721755

  13. IGF-1 potentiates sensory innervation signalling by modulating the mitochondrial fission/fusion balance

    Science.gov (United States)

    Ding, Yuan; Li, Jianmin; Liu, Zhen; Liu, Huaxiang; Li, Hao; Li, Zhenzhong

    2017-01-01

    Restoring the contractile function of long-term denervated skeletal muscle (SKM) cells is difficult due to the long period of denervation, which causes a loss of contractility. Although sensory innervation is considered a promising protective approach, its effect is still restricted. In this study, we introduced insulin-like growth factor-1 (IGF-1) as an efficient protective agent and observed that IGF-1 potentiated the effects of sensory protection by preventing denervated muscle atrophy and improving the condition of denervated muscle cells in vivo and in vitro. IGF-1-induced Akt phosphorylation suppressed the mitochondrial outer-membrane protein Mul1 expression, which is a key step on preserving contractile property of sensory innervated SKM cells. Mul1 overexpression interfered with the balance between mitochondrial fusion and fission and was a key node for blocking the effects of IGF-1 that preserved the contractility of sensory-innervated SKM cells. Activation of AMP-activated protein kinase α (AMPKα), a mitochondrial downstream target, could block the effects of IGF-1. These data provide novel evidence that might be applied when searching for new approaches to improve the functional condition of long-term denervated SKM cells by increasing sensory protection using the IGF-1 signalling system to modulate the balance between mitochondrial fusion and fission. PMID:28276453

  14. NDRG1 overexpression promotes the progression of esophageal squamous cell carcinoma through modulating Wnt signaling pathway

    Science.gov (United States)

    Ai, Runna; Sun, Yulin; Guo, Zhimin; Wei, Wei; Zhou, Lanping; Liu, Fang; Hendricks, Denver T.; Xu, Yang; Zhao, Xiaohang

    2016-01-01

    ABSTRACT N-myc down-regulated gene 1 (NDRG1) has been shown to regulate tumor growth and metastasis in various malignant tumors and also to be dysregulated in esophageal squamous cell carcinoma (ESCC). Here, we show that NDRG1 overexpression (91.9%, 79/86) in ESCC tumor tissues is associated with poor overall survival of esophageal cancer patients. When placed in stable transfectants of the KYSE 30 ESCC cell line generated by lentiviral transduction with the ectopic overexpression of NDRG1, the expression of transducin-like enhancer of Split 2 (TLE2) was decreased sharply, however β−catenin was increased. Mechanistically, NDRG1 physically associates with TLE2 and β−catenin to affect the Wnt pathway. RNA interference and TLE2 overexpression studies demonstrate that NDRG1 fails to active Wnt pathway compared with isogenic wild-type controls. Strikingly, NDRG1 overexpression induces the epithelial mesenchymal transition (EMT) through activating the Wnt signaling pathway in ESCC cells, decreased the expression of E-cadherin and enhanced the expression of Snail. Our study elucidates a mechanism of NDRG1-regulated Wnt pathway activation and EMT via affecting TLE2 and  β-catenin expression in esophageal cancer cells. This indicates a pro-oncogenic role for NDRG1 in esophageal cancer cells whereby it modulates tumor progression. PMID:27414086

  15. Social discounting involves modulation of neural value signals by temporoparietal junction

    Science.gov (United States)

    Strombach, Tina; Weber, Bernd; Hangebrauk, Zsofia; Kenning, Peter; Karipidis, Iliana I.; Tobler, Philippe N.; Kalenscher, Tobias

    2015-01-01

    Most people are generous, but not toward everyone alike: generosity usually declines with social distance between individuals, a phenomenon called social discounting. Despite the pervasiveness of social discounting, social distance between actors has been surprisingly neglected in economic theory and neuroscientific research. We used functional magnetic resonance imaging (fMRI) to study the neural basis of this process to understand the neural underpinnings of social decision making. Participants chose between selfish and generous alternatives, yielding either a large reward for the participant alone, or smaller rewards for the participant and another individual at a particular social distance. We found that generous choices engaged the temporoparietal junction (TPJ). In particular, the TPJ activity was scaled to the social-distance–dependent conflict between selfish and generous motives during prosocial choice, consistent with ideas that the TPJ promotes generosity by facilitating overcoming egoism bias. Based on functional coupling data, we propose and provide evidence for a biologically plausible neural model according to which the TPJ supports social discounting by modulating basic neural value signals in the ventromedial prefrontal cortex to incorporate social-distance–dependent other-regarding preferences into an otherwise exclusively own-reward value representation. PMID:25605887

  16. Agrimol B suppresses adipogenesis through modulation of SIRT1-PPAR gamma signal pathway.

    Science.gov (United States)

    Wang, Shifeng; Zhang, Qiao; Zhang, Yuxin; Shen, Cheng; Wang, Zhen; Wu, Qinghua; Zhang, Yanling; Li, Shiyou; Qiao, Yanjiang

    2016-08-26

    Studies of human genetics have implicated the role of SIRT1 in regulating obesity, insulin resistance, and longevity. These researches motivated the identification of novel SIRT1 activators. The current study aimed to investigate the potential efficacy of agrimol B, a polyphenol derived from Agrimonia pilosa Ledeb., on mediating SIRT1 activity and fat metabolism. Results showed that agrimol B significantly induced cytoplasm-to-nucleus shuttle of SIRT1. Furthermore, we confirmed that agrimol B dramatically inhibited 3T3-L1 adipocyte differentiation by reducing PPARγ, C/EBPα, FAS, UCP-1, and apoE expression. Consequently, adipogenesis was blocked by treatment of agrimol B at the early stage of differentiation in a dose-dependent manner, the IC50 value was determined as 3.35 ± 0.32 μM. Taken together, our data suggest a therapeutic potential of agrimol B on alleviating obesity, through modulation of SIRT1-PPARγ signal pathway. Copyright © 2016. Published by Elsevier Inc.

  17. Modulation of legume defense signaling pathways by native and non-native pea aphid clones

    Directory of Open Access Journals (Sweden)

    Carlos Sanchez-Arcos

    2016-12-01

    suggest that A. pisum clones manipulate plant-defense signaling to their own advantage, and perform better on their native hosts due to their ability to modulate the SA- and JA-defense signaling pathways.

  18. Signal transduction factors on the modulation of radiosusceptibility in K562 cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Kwang Mo; Jeong, Soo Jin [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Youn, Seon Min [College of Medicine, Eulji Univ., Daejeon (Korea, Republic of)

    2003-09-01

    The human chronic myelogenous leukemia cell line, K562, expresses the chimeric bcr-abl oncoprotein, whose deregulated protein tyrosine kinase activity antagonizes the induction of apoptosis via DNA damaging agents. Previous experiments have shown that nanomolar concentrations of herbimycin A [HMA] coupled with X-irradiation have a synergistic effect in inducing apoptosis in the Ph-positive K562 leukemia cell line, but genistein, a PTK inhibitor, is non selective for the radiation-induced apoptosis of p210{sup bcr}/{sup abl} protected K562 cells. In these experiments, the cytoplasmic signal transduction pathways, the induction of a number of transcription factors and the differential gene expression in this model were investigated. K562 cells in the exponential growth phase were used in this study. The cells were irradiated with 0.5-12 Gy, using a 6 MeV Linac (Clinac 1800, Varian, USA). Immediately after irradiation, the cells were treated with 0.25{mu}M of HMA and 25{mu}M of genistein, and the expressions and the activities of ablkinase, MAPK family, NF-KB, c-fos, c-myc, and thymidine kinase1 (TK1) were examined. The differential gene expressions induced by PTK inhibitors were also investigated. The modulating effects of herbimycin A and genistein on the radiosensitivity of K562 cells were not related to the bcr-abl kinase activity. The signaling responses through the MAPK family of proteins, were not involved either. In association with the radiation-induced apoptosis, which is accelerated by HMA, the expression of c-myc was increased. The combined treatment of genistein, with irradiation, enhanced NF-KB activity and the TK 1 expression and activity. The effects of HMA and genistein on the radiosensitivity of the K562 cells were not related to the bcr-abl kinase activity. In this study, another signaling pathway, besides the MAPK family responses to radiation to K562 cells, was found. Further evaluation using this model will provide valuable information for the

  19. Estradiol modulates TGF-β1 expression and its signaling pathway in thyroid stromal cells.

    Science.gov (United States)

    Gantus, M A V; Alves, L M; Stipursky, J; Souza, E C L; Teodoro, A J; Alves, T R; Carvalho, D P; Martinez, A M B; Gomes, F C A; Nasciutti, L E

    2011-04-30

    The higher prevalence of thyroid disease in women suggests that estrogen (E2) might be involved in the pathophysiology of thyroid dysfunction. To approach the question of the effect of stromal cells in the modulation of thyroid epithelial cells activity, we established and characterized a homogeneous stromal cell population (TS7 cells) of rat thyroid gland. These fibroblastic cells synthesize the cytoskeleton proteins α-smooth muscle actin and vimentin, produce basement membrane components and express the cytokine transforming growth factor beta 1 (TGF-β1). Here, we hypothesized that the effects of E2 on follicular thyroid cells are mediated by TGF-β1 synthesis and secretion by stromal cells (paracrine action). Thus we investigated the effect of E2 on TGF-β1 synthesis and its signaling pathway in TS7 cells. In addition, we analyzed the role of TGF-β1 signaling pathway as mediator of TS7-PC CL3 thyroid epithelial cells interactions. We report that TS7 stromal cells expressed α and β estrogen receptors (ERα and ERβ). Further, both isoforms of TGF-β1 receptors, TGFRI and TGFRII, were also identified in TS7 cells, suggesting that these cells might be a target for this cytokine in vitro. Treatment of TS7 cells with E2 induced both synthesis and secretion of TGF-β1. This event was followed by phosphorylation of the transcription factor Smad2, a hallmark of TGF-β1 pathway activation. Co-culture of PC CL3 cells onto TS7 cells monolayers yielded round aggregates of PC CL3 cells surrounded by TS7 cells. TS7 cells induced a decrease in iodide uptake by PC CL3 cells, probably by a mechanism involving TGF-β1. Moreover, E2 affected synthesis and organization of the extracellular matrix (ECM) components, tenascin C and chondroitin sulfate, in these co-culture cells. Our results point to the TGF-β1/Smad-2 signaling pathway as a putative target of estrogen actions on thyroid stromal cells and contribute to understanding the interplay between stromal and follicular

  20. Involvement of group III metabotropic glutamate receptors in the modulation of spinal nociceptive signals

    Institute of Scientific and Technical Information of China (English)

    Xiaorong Yang; Yu Zhang; Xin Zhao; Naihong Liu; Jiantian Qiao; Ce Zhang

    2009-01-01

    BACKGROUND:Previous morphological studies have demonstrated that group III metabotropic glutamate receptors (mGluRs) are commonly found in nociceptive pathways,particularly in the terminals of primary afferent fibers in the spinal dorsal horn.OBJECTIVE:To investigate the role of group III mGluRs in a rat model of spinal nociception by intrathecal administration of a selective agonist,L-Serine-O-phosphate (L-SOP).DESIGN,TIME AND SETTING:A randomized,controlled,animal experiment.The study was performed at the Department of Physiology and Neurobiology,Shanxi Medical University,between March 2007 and May 2008.MATERIALS:L-SOP of group III mGluRs (Tocris Cookson Ltd,UK),formalin (Sigma,USA),rabbit anti-c-Fos polyclonal antibody and biotin-labeled goat anti-rabbit IgG (Cell Signaling Technology,USA) were used in this study.METHODS:A total of 26 healthy Wistar rats,aged 1 month and weighing 100-120 g,were subjected to intrathecal catheter implantation.After 5-8 days,10 rats were selected according to experimental requirements.L-SOP 250 nmol in 10 μL,or the equivalent volume of normal saline,was administered by intrathecal injection into the L3-5 region of the spinal cord in the experimental and control groups,respectively.After 15 minutes,formalin (5%,50 μL) was subcutaneously injected into the plantar of the left hindpaw of each rat to establish formalin-induced pain models.MAIN OUTCOME MEASURES:Nociceptive behavioral responses and immunohistochemical examination of Fos expression.RESULTS:Intrathecal injection of L-SOP significantly attenuated the second phase nociceptive response compared with the control group (P<0.05),and Fos expression in the spinal dorsal horn was significantly decreased along with the number of Fos-like immunoreactive neurons (P<0.05).CONCLUSION:Group III mGluRs are involved in the modulation of nociceptive signals,and their activation suppresses the transmission of nociceptive signals.

  1. Coherent Detection of Wavelength Division Multiplexed Phase-Modulated Radio-over-Fibre Signals

    DEFF Research Database (Denmark)

    Zibar, Darko; Yu, Xianbin; Peucheret, Christophe

    2008-01-01

    A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km.......A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km....

  2. Response Analysis on Electrical Pulses under Severe Nuclear Accident Temperature Conditions Using an Abnormal Signal Simulation Analysis Module

    Directory of Open Access Journals (Sweden)

    Kil-Mo Koo

    2012-01-01

    Full Text Available Unlike design basis accidents, some inherent uncertainties of the reliability of instrumentations are expected while subjected to harsh environments (e.g., high temperature and pressure, high humidity, and high radioactivity occurring in severe nuclear accident conditions. Even under such conditions, an electrical signal should be within its expected range so that some mitigating actions can be taken based on the signal in the control room. For example, an industrial process control standard requires that the normal signal level for pressure, flow, and resistance temperature detector sensors be in the range of 4~20 mA for most instruments. Whereas, in the case that an abnormal signal is expected from an instrument, such a signal should be refined through a signal validation process so that the refined signal could be available in the control room. For some abnormal signals expected under severe accident conditions, to date, diagnostics and response analysis have been evaluated with an equivalent circuit model of real instruments, which is regarded as the best method. The main objective of this paper is to introduce a program designed to implement a diagnostic and response analysis for equivalent circuit modeling. The program links signal analysis tool code to abnormal signal simulation engine code not only as a one body order system, but also as a part of functions of a PC-based ASSA (abnormal signal simulation analysis module developed to obtain a varying range of the R-C circuit elements in high temperature conditions. As a result, a special function for abnormal pulse signal patterns can be obtained through the program, which in turn makes it possible to analyze the abnormal output pulse signals through a response characteristic of a 4~20 mA circuit model and a range of the elements changing with temperature under an accident condition.

  3. A Simple Signal Shaper for GMSK/GFSK and MSK Modulator Based on Sigma-Delta Look-up Table

    Directory of Open Access Journals (Sweden)

    T. Svedek

    2009-06-01

    Full Text Available Due to wide power spectrums of rectangular data streams, it is important for base-band signals to be heavily band limited before modulation. That can be achieved by pulse shaping of rectangular bits. Some of the most common are a half-sine pulse shaper and a Gaussian pulse shaper which are used in Minimum Shift Keying (MSK, Gaussian Minimum Shift Keying (GMSK and Gaussian Frequency Shift Keying (GFSK modulations, respectively. The most common solutions of such shapers use PCM based look-up-table (LUT, which requires an nbit D/A converter. We proposed the use of a 1-bit Sigma Delta Modulation (SDM LUT, which results in smaller ROM capacity, a 1-bit wide output word, and a simple1-bit D/A converter realized as an out-of-chip first-order lowpass RC filter, or an in-chip charge pump. This article describes a simple, but efficient SDM LUT-based half-sine and Gaussian shaper that can be used for generation of MSK and GMSK/GFSK modulated signals. Oscillograms and power spectrums are measured on SDM LUT realized in FLEX AlteraTM PLD, for a 10-bit pseudo-noise sequence test input signal.

  4. An autonomous battery-less sensor module powered by piezoelectric energy harvesting with RF transmission of multiple measurement signals

    Science.gov (United States)

    Ferrari, Marco; Ferrari, Vittorio; Guizzetti, Michele; Marioli, Daniele

    2009-08-01

    An energy-autonomous battery-less sensor module is presented, entirely powered by a piezoelectric energy converter driven by mechanical vibrations from the environment. The module manages and stores the converted energy, interfaces to one or more passive sensors and periodically sends the corresponding measurement signals over a radio-frequency (RF) link. As an additional variant, the module can send a programmable identification (ID) code on the RF carrier, in order to enable module tagging and tracking by the external receiver unit. The module's general architecture is presented and the strategy used for sensor signal conditioning and transmission is illustrated. The architecture and principle have been experimentally validated on a fabricated prototype including a piezoelectric bimorph converter, two passive sensors made by a resistive-capacitive sensor pair and purposely designed electronic circuitry based on low-power off-the-shelf components. In the tested experimental conditions, the prototype features a typical time interval between measurement-and-transmission events of a few tens of seconds, with event durations of the order of tens of milliseconds, corresponding to an operation duty cycle of the order of 0.1%. Peak power consumption during transmission is of the order of 20 mW and operative range is of the order of meters in a laboratory environment. The obtained results show that the proposed approach has attractive characteristics because of the total absence of batteries and, despite the inherent intermittent operation, provides significant measurement performances in terms of achievable sensitivity and resolution.

  5. Taurine chloramine modulates the expression of adipokines through inhibition of the STAT-3 signaling pathway in differentiated human adipocytes.

    Science.gov (United States)

    Kim, Kyoung Soo; Ji, Hye-In; Chung, Hyunju; Kim, Chakyeun; Lee, Sang Hoon; Lee, Yeon-Ah; Yang, Hyung-In; Yoo, Myung Chul; Hong, Seung Jae

    2013-12-01

    To examine the possible role of taurine chloramine (TauCl) in modulating the expression of adipokines in adipose tissue associated with obesity, we evaluated the effect of TauCl in human differentiated adipocytes in response to IL-1β. To study the physiological effects of TauCl on adipokine expression, differentiated adipocytes were treated with IL-1β in the presence or absence of TauCl at concentrations ranging from 200 to 600 μM for 7 days. Cell culture supernatants and total RNA were analyzed by ELISA and real-time PCR, respectively, to determine protein and mRNA levels of adipokines, including adiponectin, leptin, IL-6, and IL-8. Levels of proteins involved in relevant signaling pathways were investigated by western blotting. Stimulation with IL-1β significantly decreased levels of adiponectin and leptin in adipocytes, but increased levels of IL-6 and IL-8 in a dose-dependent manner. Treatment with TauCl significantly reversed the modulation of adipokine expression by inhibiting STAT-3 signaling in IL-1β-stimulated adipocytes, independent of MAPK signaling. TauCl treatment more significantly modulated the expression of adipokines in adipocytes stimulated with IL-1β than that of non-stimulated adipocytes, suggesting that TauCl plays a significant role in modulating the expression of adipokines under inflammatory conditions. In conclusion, TauCl and other taurine derivatives that inhibit the STAT-3 signaling pathway can modulate expression of adipokines and thus may be useful as therapeutic agents for obesity-related diseases.

  6. Signal-signal beat interference cancellation in spectrally-efficient WDM direct-detection Nyquist-pulse-shaped 16-QAM subcarrier modulation.

    Science.gov (United States)

    Li, Zhe; Erkılınç, M Sezer; Pachnicke, Stephan; Griesser, Helmut; Bouziane, Rachid; Thomsen, Benn C; Bayvel, Polina; Killey, Robert I

    2015-09-01

    An experimental demonstration of direct-detection single-sideband Nyquist-pulse-shaped 16-QAM subcarrier modulated (Nyquist-SCM) transmission implementing a receiver-based signal-signal beat interference (SSBI) cancellation technique is described. The performance improvement with SSBI mitigation, which compensates for the nonlinear distortion caused by square-law detection, was quantified by simulations and experiments for a 7 × 25 Gb/s WDM Nyquist-SCM signal with a net optical information spectral density (ISD) of 2.0 (b/s)/Hz. A reduction of 3.6 dB in the back-to-back required OSNR at the HD-FEC threshold was achieved. The resulting reductions in BER in single channel and WDM transmission over distances of up to 800 km of uncompensated standard single-mode fiber (SSMF) achieved are presented.

  7. Spectrum of the nonstationary electromyographic signal modelled with integral pulse frequency modulation and its application to estimating neural drive information.

    Science.gov (United States)

    Jiang, Ning; Parker, Philip A; Englehart, Kevin B

    2009-08-01

    The spectrum of nonstationary electromyographic signal (EMG) is investigated, from which the error for neural drive information estimation from nonstationary EMG is studied in terms of signal-to-noise ratio (SNR), in analytical, numerical simulation, and experimental work. The signal refers to the neural drive information embedded within the nonstationary EMG, and noise refers to other portions of EMG that induce error in the estimation. The analytical expressions for the SNRs of force-modulated EMG with both single and multiple motor units (MU) are derived based on a sinusoidal integral pulse frequency modulation (IPFM) model. It is shown that the previously developed SNR expressions for stationary (unmodulated) EMG are special cases of the formulas presented here. The SNR results obtained from numerical simulated EMG agree very well with the analytical result. Results from nonstationary (modulated) surface EMG obtained from seven subjects also match the analytical and simulation results reasonably well. The results obtained from this work establish an analytical framework in studying and estimating the neural drive information contained in the EMG in the context of anisotonic and isometric contractions. Through the analytical study, the effects of different physiological parameters are identified, thus providing theoretical guidelines for developing advanced signal processing methods for nonstationary EMG in applications such as prosthesis control.

  8. Tissue-specific activities of an immune signaling module regulate physiological responses to pathogenic and nutritional bacteria in C. elegans.

    Science.gov (United States)

    Shivers, Robert P; Kooistra, Tristan; Chu, Stephanie W; Pagano, Daniel J; Kim, Dennis H

    2009-10-22

    Microbes represent both an essential source of nutrition and a potential source of lethal infection to the nematode Caenorhabditis elegans. Immunity in C. elegans requires a signaling module comprised of orthologs of the mammalian Toll-interleukin-1 receptor (TIR) domain protein SARM, the mitogen-activated protein kinase kinase kinase (MAPKKK) ASK1, and MAPKK MKK3, which activates p38 MAPK. We determined that the SARM-ASK1-MKK3 module has dual tissue-specific roles in the C. elegans response to pathogens--in the cell-autonomous regulation of innate immunity and the neuroendocrine regulation of serotonin-dependent aversive behavior. SARM-ASK1-MKK3 signaling in the sensory nervous system also regulates egg-laying behavior that is dependent on bacteria provided as a nutrient source. Our data demonstrate that these physiological responses to bacteria share a common mechanism of signaling through the SARM-ASK1-MKK3 module and suggest the co-option of ancestral immune signaling pathways in the evolution of physiological responses to microbial pathogens and nutrients.

  9. Nutrient-regulated antisense and intragenic RNAs modulate a signal transduction pathway in yeast.

    Directory of Open Access Journals (Sweden)

    Masafumi Nishizawa

    2008-12-01

    Full Text Available The budding yeast Saccharomyces cerevisiae alters its gene expression profile in response to a change in nutrient availability. The PHO system is a well-studied case in the transcriptional regulation responding to nutritional changes in which a set of genes (PHO genes is expressed to activate inorganic phosphate (Pi metabolism for adaptation to Pi starvation. Pi starvation triggers an inhibition of Pho85 kinase, leading to migration of unphosphorylated Pho4 transcriptional activator into the nucleus and enabling expression of PHO genes. When Pi is sufficient, the Pho85 kinase phosphorylates Pho4, thereby excluding it from the nucleus and resulting in repression (i.e., lack of transcription of PHO genes. The Pho85 kinase has a role in various cellular functions other than regulation of the PHO system in that Pho85 monitors whether environmental conditions are adequate for cell growth and represses inadequate (untimely responses in these cellular processes. In contrast, Pho4 appears to activate some genes involved in stress response and is required for G1 arrest caused by DNA damage. These facts suggest the antagonistic function of these two players on a more general scale when yeast cells must cope with stress conditions. To explore general involvement of Pho4 in stress response, we tried to identify Pho4-dependent genes by a genome-wide mapping of Pho4 and Rpo21 binding (Rpo21 being the largest subunit of RNA polymerase II using a yeast tiling array. In the course of this study, we found Pi- and Pho4-regulated intragenic and antisense RNAs that could modulate the Pi signal transduction pathway. Low-Pi signal is transmitted via certain inositol polyphosphate (IP species (IP7 that are synthesized by Vip1 IP6 kinase. We have shown that Pho4 activates the transcription of antisense and intragenic RNAs in the KCS1 locus to down-regulate the Kcs1 activity, another IP6 kinase, by producing truncated Kcs1 protein via hybrid formation with the KCS1 m

  10. Dietary chlorophyllin abrogates TGFβ signaling to modulate the hallmark capabilities of cancer in an animal model of forestomach carcinogenesis.

    Science.gov (United States)

    Thiyagarajan, Paranthaman; Kavitha, Krishnamurthy; Thautam, Avaneesh; Dixit, Madhulika; Nagini, Siddavaram

    2014-07-01

    Transforming growth factor (TGF) β signaling pathway plays a central role in the regulation of a wide range of cellular processes involved in the acquisition of the malignant phenotype. The objective of the present study was to examine the effect of chlorophyllin, a semisynthetic derivative of chlorophyll on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)--induced rat forestomach carcinogenesis based on the modulation of TGFβ signaling and the downstream target genes associated with cell proliferation, apoptosis evasion, angiogenesis, invasion, and metastasis. We determined the effect of dietary chlorophyllin on TGFβ signaling and the downstream events-cell proliferation, apoptosis evasion, angiogenesis, invasion, and metastasis by semiquantitative and quantitative reverse transcription (RT)-PCR, Western blot, and immunohistochemical analyses. We further validated the inhibition of TGFβ signaling by chlorophyllin by performing molecular docking studies. We found that dietary supplementation of chlorophyllin at 4-mg/kg bw inhibits the development of MNNG-induced forestomach carcinomas by downregulating the expression of TGFβ RI, TGFβ RII, and Smad 2 and 4 and upregulating Smad 7, thereby abrogating canonical TGFβ signaling. Docking interactions also confirmed the inhibition of TGFβ signaling by chlorophyllin via inactivating TGFβ RI. Furthermore, attenuation of TGFβ signaling by chlorophyllin also blocked cell proliferation, angiogenesis, invasion, and metastasis, and induced mitochondria-mediated cell death. Dietary chlorophyllin that simultaneously abrogates TGFβ signaling pathway and the key hallmark events of cancer appear to be an ideal candidate for cancer chemoprevention.

  11. ESCRT-II/Vps25 constrains digit number by endosome-mediated selective modulation of FGF-SHH signaling.

    Science.gov (United States)

    Handschuh, Karen; Feenstra, Jennifer; Koss, Matthew; Ferretti, Elisabetta; Risolino, Maurizio; Zewdu, Rediet; Sahai, Michelle A; Bénazet, Jean-Denis; Peng, Xiao P; Depew, Michael J; Quintana, Laura; Sharpe, James; Wang, Baolin; Alcorn, Heather; Rivi, Roberta; Butcher, Stephen; Manak, J Robert; Vaccari, Thomas; Weinstein, Harel; Anderson, Kathryn V; Lacy, Elizabeth; Selleri, Licia

    2014-10-23

    Sorting and degradation of receptors and associated signaling molecules maintain homeostasis of conserved signaling pathways during cell specification and tissue development. Yet, whether machineries that sort signaling proteins act preferentially on different receptors and ligands in different contexts remains mysterious. Here, we show that Vacuolar protein sorting 25, Vps25, a component of ESCRT-II (Endosomal Sorting Complex Required for Transport II), directs preferential endosome-mediated modulation of FGF signaling in limbs. By ENU-induced mutagenesis, we isolated a polydactylous mouse line carrying a hypomorphic mutation of Vps25 (Vps25(ENU)). Unlike Vps25-null embryos we generated, Vps25(ENU/ENU) mutants survive until late gestation. Their limbs display FGF signaling enhancement and consequent hyperactivation of the FGF-SHH feedback loop causing polydactyly, whereas WNT and BMP signaling remain unperturbed. Notably, Vps25(ENU/ENU) Mouse Embryonic Fibroblasts exhibit aberrant FGFR trafficking and degradation; however, SHH signaling is unperturbed. These studies establish that the ESCRT-II machinery selectively limits FGF signaling in vertebrate skeletal patterning.

  12. Coordinated modulation of cellular signaling through ligand-gated ion channels in Hydra vulgaris (Cnidaria, Hydrozoa).

    Science.gov (United States)

    Pierobon, Paola

    2012-01-01

    Cnidarians lack well developed organs, but they have evolved the molecular and cellular components needed to assemble a nervous system. The apparent 'simplicity' of the cnidarian nervous net does not occur at the cellular level, but rather in the organisation of conducting systems. Cnidarian neurons are in fact electrically excitable, show the typical extended morphology and are connected by chemical synapses or gap junctions. They have been regarded as peptidergic, given the wealth of neuropeptides generally distributed along neurites and in cell bodies, supporting the hypothesis of a modulatory role in neurotransmission. However, the presence of clear-cored, as well as dense-cored synaptic vesicles in cnidarian neurons suggests both fast and slow synaptic transmission mechanisms. In fact, biochemical and functional evidence indicates that classical neurotransmitters and their metabolic partners are present in cnidarian tissues, where they are involved in coordinating motility and behavior. We have identified and characterized in Hydra tissues receptors to the inhibitory and excitatory amino acid neurotransmitters, GABA, glycine and NMDA, that are similar to mammalian ionotropic receptors in terms of their biochemical and pharmacological properties. These receptors appear to regulate pacemaker activities and their physiological correlates; in the live animal, they also affect feeding behavior, namely the duration and termination of the response elicited by reduced glutathione, with opposite actions of GABA and glycine or NMDA, respectively. These results suggest that modulation of cellular signaling through ligand-gated-ion channels is an ancient characteristic in the animal kingdom, and that the pharmacological properties of these receptors have been highly conserved during evolution.

  13. Effect of Physical Exercise on the Febrigenic Signaling is Modulated by Preoptic Hydrogen Sulfide Production

    Science.gov (United States)

    Nogueira, Jonatas E.; Soriano, Renato N.; Fernandez, Rodrigo A. R.; Francescato, Heloísa D. C.; Saia, Rafael S.; Coimbra, Terezila M.; Antunes-Rodrigues, José; Branco, Luiz G. S.

    2017-01-01

    We tested the hypothesis that the neuromodulator hydrogen sulfide (H2S) in the preoptic area (POA) of the hypothalamus modulates the febrigenic signaling differently in sedentary and trained rats. Besides H2S production rate and protein expressions of H2S-related synthases cystathionine β-synthase (CBS), 3-mercaptopyruvate sulfurtransferase (3-MPST) and cystathionine γ-lyase (CSE) in the POA, we also measured deep body temperature (Tb), circulating plasma levels of cytokines and corticosterone in an animal model of systemic inflammation. Rats run on a treadmill before receiving an intraperitoneal injection of lipopolysaccharide (LPS, 100 μg/kg) or saline. The magnitude of changes of Tb during the LPS-induced fever was found to be similar between sedentary and trained rats. In sedentary rats, H2S production was not affected by LPS. Conversely, in trained rats LPS caused a sharp increase in H2S production rate that was accompanied by an increased CBS expression profile, whereas 3-MPST and CSE expressions were kept relatively constant. Sedentary rats showed a significant LPS-induced release of cytokines (IL-1β, IL-6, and TNF-α) which was virtually abolished in the trained animals. Correlation between POA H2S and IL-6 as well as TNF-α was observed. Corticosterone levels were augmented after LPS injection in both groups. We found correlations between H2S and corticosterone, and corticosterone and IL-1β. These data are consistent with the notion that the responses to systemic inflammation are tightly regulated through adjustments in POA H2S production which may play an anti-inflammatory role downmodulating plasma cytokines levels and upregulating corticosterone release. PMID:28118407

  14. Effect of Physical Exercise on the Febrigenic Signaling is Modulated by Preoptic Hydrogen Sulfide Production.

    Science.gov (United States)

    Nogueira, Jonatas E; Soriano, Renato N; Fernandez, Rodrigo A R; Francescato, Heloísa D C; Saia, Rafael S; Coimbra, Terezila M; Antunes-Rodrigues, José; Branco, Luiz G S

    2017-01-01

    We tested the hypothesis that the neuromodulator hydrogen sulfide (H2S) in the preoptic area (POA) of the hypothalamus modulates the febrigenic signaling differently in sedentary and trained rats. Besides H2S production rate and protein expressions of H2S-related synthases cystathionine β-synthase (CBS), 3-mercaptopyruvate sulfurtransferase (3-MPST) and cystathionine γ-lyase (CSE) in the POA, we also measured deep body temperature (Tb), circulating plasma levels of cytokines and corticosterone in an animal model of systemic inflammation. Rats run on a treadmill before receiving an intraperitoneal injection of lipopolysaccharide (LPS, 100 μg/kg) or saline. The magnitude of changes of Tb during the LPS-induced fever was found to be similar between sedentary and trained rats. In sedentary rats, H2S production was not affected by LPS. Conversely, in trained rats LPS caused a sharp increase in H2S production rate that was accompanied by an increased CBS expression profile, whereas 3-MPST and CSE expressions were kept relatively constant. Sedentary rats showed a significant LPS-induced release of cytokines (IL-1β, IL-6, and TNF-α) which was virtually abolished in the trained animals. Correlation between POA H2S and IL-6 as well as TNF-α was observed. Corticosterone levels were augmented after LPS injection in both groups. We found correlations between H2S and corticosterone, and corticosterone and IL-1β. These data are consistent with the notion that the responses to systemic inflammation are tightly regulated through adjustments in POA H2S production which may play an anti-inflammatory role downmodulating plasma cytokines levels and upregulating corticosterone release.

  15. The importance of dietary modulation of cAMP and insulin signaling in adipose tissue and the development of obesity

    DEFF Research Database (Denmark)

    Madsen, Lise; Kristiansen, Karsten

    2010-01-01

    Adipose tissue plays a pivotal role in whole body energy homeostasis. In this review, we summarize knowledge of the seemingly paradoxical roles of insulin and cyclic adenosine monophosphate (cAMP) signaling in adipocyte differentiation and function, emphasizing the interplay between the two...... branches of cAMP signaling, the canonical protein kinase A-dependent pathways and the novel exchange protein activated by cAMP (Epac)-dependent pathways, and insulin signaling. We discuss how macronutrients via changes in the balance between insulin- and cAMP-dependent signaling can affect the development...... of obesity by changing energy expenditure and/or feed efficiency. We review results demonstrating how the balance between different classes of carbohydrates and proteins modulates the obesigenic action of saturated as well as unsaturated fatty acids pointing to insulin as a key determinant in the regulation...

  16. Converged Wireless and Wireline Access System Based on Optical Phase Modulation for Both Radio-Over-Fiber and Baseband Signals

    DEFF Research Database (Denmark)

    Yu, Xianbin; Jensen, Jesper Bevensee; Zibar, Darko

    2008-01-01

    We propose and experimentally investigate a scheme for transmitting a phase-modulated radio-over-fiber (RoF) signal along an existing fiber infrastructure without degradation of the existing baseband signal. Optical phase encoding of both signals, namely a baseband 21.4-Gb/s nonreturn......-to-zero differential quaternary phase-shift keyed signal and a 5.25-GHz RoF carrying 1.25 Gb/s, enables the use of identical optical receiver structures. The experimental results show that both receivers achieve error-free operation after 80-km standard single-mode fiber transmission. The proposed scheme has potential...... applications for converged wireless and wireline optical access networks....

  17. W-band OFDM photonic vector signal generation employing a single Mach-Zehnder modulator and precoding.

    Science.gov (United States)

    Xiao, Jiangnan; Li, Xinying; Xu, Yuming; Zhang, Ziran; Chen, Long; Yu, Jianjun

    2015-09-07

    We present a simple radio-over-fiber (RoF) link architecture for millimeter-wave orthogonal frequency division multiplexing (OFDM) transmission using only one Mach-Zehnder modulator (MZM) and precoding technique. In the transmission system, the amplitudes and the phase of the driving radio-frequency (RF) OFDM signal on each sub-carrier are precoded, to ensure that the OFDM signal after photodetector (PD) can be restored to original OFDM signal. The experimental results show that the bit-error ratios (BERs) of the transmission system are less than the forward-error-correction (FEC) threshold of 3.8 × 10(-3), which demonstrates that the generation of OFDM vector signal based on our proposed scheme can be employed in our system architecture.

  18. Development of Power Supply Management Module for Radio Signal Repeaters of Automatic Metering Reading System in Variable Solar Density Conditions

    Directory of Open Access Journals (Sweden)

    Kondratjevs K.

    2016-02-01

    Full Text Available In recent years, there has been significant research focus that revolves around harvesting and minimising energy consumption by wireless sensor network nodes. When a sensor node is depleted of energy, it becomes unresponsive and disconnected from the network that can significantly influence the performance of the whole network. The purpose of the present research is to create a power supply management module in order to provide stable operating voltage for autonomous operations of radio signal repeaters, sensors or gateways of WSN. The developed management module is composed of a solar panel, lithium battery and power supply management module. The novelty of the research is the management module, which ensures stable and uninterrupted operations of electronic equipment in various power supply modes in different situations, simultaneously ensuring energy protection and sustainability of the module components. The management module is able to provide power supply of 5 V for electronics scheme independently, without power interruption switching between power sources and power flows in different directions.

  19. Theoretical investigations of quantum-dot semiconductor optical amplifier enabled intensity modulation of adaptively modulated optical OFDM signals in IMDD PON systems.

    Science.gov (United States)

    Hamié, A; Hamze, M; Wei, J L; Sharaiha, A; Tang, J M

    2011-12-05

    Extensive explorations are undertaken, for the first time, of the feasibility of utilizing quantum-dot semiconductor optical amplifier intensity modulators (QD-SOA-IMs) in cost-sensitive intensity-modulation and direct-detection (IMDD) passive optical network (PON) systems based on adaptively modulated optical orthogonal frequency division multiplexing (AMOOFDM). A theoretical QD-SOA-IM model is developed, based on which optimum QD-SOA-IM operating conditions are identified together with major physical mechanism considerably affecting the system performance. It is shown that, in comparison with previously reported SOA-IMs in similar transmission systems, QD-SOA-IMs cannot only considerably improve the AMOOFDM transmission performance but also broaden the dynamic range of optimum operating conditions. In particular, for achieving signal bit rates of >30Gb/s over >60km single mode fiber (SMF), QD-SOA-IMs offer a 10dB reduction in CW optical input powers injected into the modulators. In addition, QD-SOA-IMs can also be employed to compensate the chromatic dispersion effect.

  20. Automatic Frequency Identification under Sample Loss in Sinusoidal Pulse Width Modulation Signals Using an Iterative Autocorrelation Algorithm

    Directory of Open Access Journals (Sweden)

    Alejandro Said

    2016-08-01

    Full Text Available In this work, we present a simple algorithm to calculate automatically the Fourier spectrum of a Sinusoidal Pulse Width Modulation Signal (SPWM. Modulated voltage signals of this kind are used in industry by speed drives to vary the speed of alternating current motors while maintaining a smooth torque. Nevertheless, the SPWM technique produces undesired harmonics, which yield stator heating and power losses. By monitoring these signals without human interaction, it is possible to identify the harmonic content of SPWM signals in a fast and continuous manner. The algorithm is based in the autocorrelation function, commonly used in radar and voice signal processing. Taking advantage of the symmetry properties of the autocorrelation, the algorithm is capable of estimating half of the period of the fundamental frequency; thus, allowing one to estimate the necessary number of samples to produce an accurate Fourier spectrum. To deal with the loss of samples, i.e., the scan backlog, the algorithm iteratively acquires and trims the discrete sequence of samples until the required number of samples reaches a stable value. The simulation shows that the algorithm is not affected by either the magnitude of the switching pulses or the acquisition noise.

  1. The Arabidopsis small GTPase AtRAC7/ROP9 is a modulator of auxin and abscisic acid signalling

    Science.gov (United States)

    Cheung, Alice Y.

    2013-01-01

    Rac-like GTPases or Rho-related GTPases from plants (RAC/ROPs) are important components of hormone signalling pathways in plants. Based on phylogeny, several groups can be distinguished, and the underlying premise is that members of different groups perform distinct functions in the plant. AtRAC7/ROP9 is phylogenetically unique among 11 Arabidopsis RAC/ROPs, and here it was shown that it functions as a modulator of auxin and abscisic acid (ABA) signalling, a dual role not previously assigned to these small GTPases. Plants with reduced levels of AtRAC7/ROP9 had increased sensitivity to auxin and were less sensitive to ABA. On the other hand, overexpressing AtRAC7/ROP9 activated ABA-induced gene expression but repressed auxin-induced gene expression. In addition, both hormones regulated the activity of the AtRAC7/ROP9 promoter, suggesting a feedback mechanism to modulate the signalling output from the AtRAC7/ROP9-controlled molecular switch. High levels of AtRAC7/ROP9 were detected specifically in embryos and lateral roots, underscoring the important role of this protein during embryo development and lateral root formation. These results place AtRAC7/ROP9 as an important signal transducer in recently described pathways that integrate auxin and ABA signalling in the plant. PMID:23918972

  2. The Natural Flavonoid Fisetin Inhibits Cellular Proliferation of Hepatic, Colorectal, and Pancreatic Cancer Cells through Modulation of Multiple Signaling Pathways.

    Science.gov (United States)

    Youns, Mаhmoud; Abdel Halim Hegazy, Wael

    2017-01-01

    Digestive cancers are major causes of mortality and morbidity worldwide. Fisetin, a naturally occurring flavonoid, has been previously shown anti-proliferative, anti-cancer, neuroprotective, and antioxidant activities. In our study, the anti-tumor activities in addition to regulatory effects of fisetin on some cancer cell lines were investigated. Data presented here showed that fisetin induces growth inhibition, and apoptosis in hepatic (HepG-2), colorectal (Caco-2) and pancreatic (Suit-2) cancer cell lines. Gene expression results showed that 1307 genes were significantly regulated in their expression in hepatic and pancreatic cell lines. 350 genes were commonly up-regulated and 353 genes were commonly down-regulated. Additionally, 604 genes were oppositely expressed in both tumor cells. CDK5 signaling, NRF2-mediated oxidative stress response, glucocorticoid signaling, and ERK/MAPK signaling were among most prominent signaling pathways modulating the growth inhibitory effects of fisetin on hepatic and pancreatic cancer cells. The present analysis showed, for the first time, that the anti-tumor effect of fisetin was mediated mainly through modulation of multiple signaling pathways and via activation of CDKN1A, SEMA3E, GADD45B and GADD45A and down-regulation of TOP2A, KIF20A, CCNB2 and CCNB1 genes.

  3. The Natural Flavonoid Fisetin Inhibits Cellular Proliferation of Hepatic, Colorectal, and Pancreatic Cancer Cells through Modulation of Multiple Signaling Pathways

    Science.gov (United States)

    Youns, Mаhmoud; Abdel Halim Hegazy, Wael

    2017-01-01

    Digestive cancers are major causes of mortality and morbidity worldwide. Fisetin, a naturally occurring flavonoid, has been previously shown anti-proliferative, anti-cancer, neuroprotective, and antioxidant activities. In our study, the anti-tumor activities in addition to regulatory effects of fisetin on some cancer cell lines were investigated. Data presented here showed that fisetin induces growth inhibition, and apoptosis in hepatic (HepG-2), colorectal (Caco-2) and pancreatic (Suit-2) cancer cell lines. Gene expression results showed that 1307 genes were significantly regulated in their expression in hepatic and pancreatic cell lines. 350 genes were commonly up-regulated and 353 genes were commonly down-regulated. Additionally, 604 genes were oppositely expressed in both tumor cells. CDK5 signaling, NRF2-mediated oxidative stress response, glucocorticoid signaling, and ERK/MAPK signaling were among most prominent signaling pathways modulating the growth inhibitory effects of fisetin on hepatic and pancreatic cancer cells. The present analysis showed, for the first time, that the anti-tumor effect of fisetin was mediated mainly through modulation of multiple signaling pathways and via activation of CDKN1A, SEMA3E, GADD45B and GADD45A and down-regulation of TOP2A, KIF20A, CCNB2 and CCNB1 genes. PMID:28052097

  4. Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

    OpenAIRE

    Platino, M.; Inan, U.S.; Bell, T. F.; Pickett, J; Kennedy, E J; Trotignon, J. G.; Rauch, J. L.; Canu, P.

    2004-01-01

    It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and high-altitude satellite observations have also been reported (James et al., 1990). One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere ill...

  5. Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

    OpenAIRE

    Platino, M.; U. S. Inan; Bell, T.F.; Pickett, J.; Kennedy, E.J.; J. G. Trotignon; Rauch, J.L.; P. Canu

    2004-01-01

    It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and high-altitude satellite observations have also been reported (James et al., 1990). One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere ill...

  6. Suppression of phase-induced intensity noise in fibre optic delay line signal processors using an optical phase modulation technique.

    Science.gov (United States)

    Chan, Erwin H W

    2010-10-11

    A technique that can suppress the dominant phase-induced intensity noise in fibre optic delay line signal processors is presented. It is based on phase modulation of the optical carrier to distribute the phase noise at the information band into a high frequency band which can be filtered out. This technique is suitable for suppressing the phase noise in various delay line structures and for integrating in the conventional fibre optic links. It can also suppress the coherent interference effect at the same time. A model for predicting the amount of phase noise reduction in various delay line structures using the optical phase modulation technique is presented for the first time and is experimentally verified. Experimental results demonstrate the technique can achieve a large phase noise reduction in various fibre optic delay line signal processors.

  7. Low Cost Em Signal Spectral Analysis with Two Element Time Modulated Array System by Multiple Signal Classification Algorithms

    Directory of Open Access Journals (Sweden)

    G. Balagurappa,

    2014-03-01

    Full Text Available Today homeland security is a big matter of concern. The present day wireless technology is available to anti-social elements, who are using this in several undesirable manners. By knowing the direction of the source of electromagnetic waves it becomes possible to locate such anti-social groups and take offensive action. In military applications also finding the direction of the signal source becomes very valuable information. The direction finding systems can achieve this goal. Conventional radio direction finding (RDF systems often use an array of two or more antennas and use either phase-comparison or amplitude-comparison of the received signals to determine direction of arrival information. In both of these techniques directional information is derived by processing array data at the receive signal frequency. In this project an alternative approach to direction finding using the concept of a time-switched array is proposed. The time-switched array system uses simple signal processing techniques to provide a directional main beam and pattern nulls at harmonic frequencies. To determine two dimensional angles is three elements, the system cost has been mostly minimised. we now consider the problem of using our low cost system to detect and estimate the direction of arrival of a desired signal in the presence of array antenna. The proposed scheme is cost effective technique in comparison with the existing schemes. MATLAB/GNU OCTAVE simulation tool will be used for simulation. The simulation results, applications, merits and demerits of proposed approach will be analyzed and will be documented.

  8. Tunable true-time delay of a microwave photonic signal realized by cross gain modulation in a semiconductor waveguide

    DEFF Research Database (Denmark)

    Xue, Weiqi; Mørk, Jesper

    2011-01-01

    We experimentally demonstrate the realization of a tunable true-time delay for microwave signals by exploiting cross gain modulation among counter-propagating optical beams in a semiconductor optical amplifier. Broadband operation from ∼5 to ∼35 GHz is observed. The physical effect originates from...... of the true-time delay and the microwave bandwidth is discussed. © 2011 American Institute of Physics....

  9. Efficient and Robust Detection of GFSK Signals under Dispersive Channel, Modulation Index, and Carrier Frequency Offset Conditions

    Directory of Open Access Journals (Sweden)

    Stephan Weiss

    2005-09-01

    Full Text Available Gaussian frequency shift keying is the modulation scheme specified for Bluetooth. Signal adversities typical in Bluetooth networks include AWGN, multipath propagation, carrier frequency, and modulation index offsets. In our effort to realise a robust but efficient Bluetooth receiver, we adopt a high-performance matched-filter-based detector, which is near optimal in AWGN, but requires a prohibitively costly filter bank for processing of K bits worth of the received signal. However, through filtering over a single bit period and performing phase propagation of intermediate results over successive single-bit stages, we eliminate redundancy involved in providing the matched filter outputs and reduce its complexity by up to 90% (for K=9. The constant modulus signal characteristic and the potential for carrier frequency offsets make the constant modulus algorithm (CMA suitable for channel equalisation, and we demonstrate its effectiveness in this paper. We also introduce a stochastic gradient-based algorithm for carrier frequency offset correction, and show that the relative rotation between successive intermediate filter outputs enables us to detect and correct offsets in modulation index.

  10. SPATA2 links CYLD to the TNF-α receptor signaling complex and modulates the receptor signaling outcomes

    DEFF Research Database (Denmark)

    Wagner, Sebastian A; Satpathy, Shankha; Beli, Petra;

    2016-01-01

    of the TNF-RSC The predicted PUB domain in the N-terminus of SPATA2 interacts with the USP domain of CYLD, whereas the C-terminus of SPATA2 interacts with HOIP SPATA2 is required for recruitment of CYLD to the TNF-RSC Downregulation of SPATA2 augments transcriptional activation of NF-κB and inhibits TNF......TNF-α is a key regulator of innate immune and proinflammatory responses. However, the composition of the TNF-α receptor-associated signaling complexes (TNF-RSC) and the architecture of the downstream signaling networks are incompletely understood. We employed quantitative mass spectrometry...... to demonstrate that TNF-α stimulation induces widespread protein phosphorylation and that the scope of phosphorylation expands in a temporal manner. TNF-α stimulation also induces rapid ubiquitylation of components of the TNF-RSC Temporal analysis of the TNF-RSC composition identified SPATA2 as a novel component...

  11. Repression of a potassium channel by nuclear hormone receptor and TGF-β signaling modulates insulin signaling in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Donha Park

    Full Text Available Transforming growth factor β (TGF-β signaling acts through Smad proteins to play fundamental roles in cell proliferation, differentiation, apoptosis, and metabolism. The Receptor associated Smads (R-Smads interact with DNA and other nuclear proteins to regulate target gene transcription. Here, we demonstrate that the Caenorhabditis elegans R-Smad DAF-8 partners with the nuclear hormone receptor NHR-69, a C. elegans ortholog of mammalian hepatocyte nuclear factor 4α HNF4α, to repress the exp-2 potassium channel gene and increase insulin secretion. We find that NHR-69 associates with DAF-8 both in vivo and in vitro. Functionally, daf-8 nhr-69 double mutants show defects in neuropeptide secretion and phenotypes consistent with reduced insulin signaling such as increased expression of the sod-3 and gst-10 genes and a longer life span. Expression of the exp-2 gene, encoding a voltage-gated potassium channel, is synergistically increased in daf-8 nhr-69 mutants compared to single mutants and wild-type worms. In turn, exp-2 acts selectively in the ASI neurons to repress the secretion of the insulin-like peptide DAF-28. Importantly, exp-2 mutation shortens the long life span of daf-8 nhr-69 double mutants, demonstrating that exp-2 is required downstream of DAF-8 and NHR-69. Finally, animals over-expressing NHR-69 specifically in DAF-28-secreting ASI neurons exhibit a lethargic, hypoglycemic phenotype that is rescued by exogenous glucose. We propose a model whereby DAF-8/R-Smad and NHR-69 negatively regulate the transcription of exp-2 to promote neuronal DAF-28 secretion, thus demonstrating a physiological crosstalk between TGF-β and HNF4α-like signaling in C. elegans. NHR-69 and DAF-8 dependent regulation of exp-2 and DAF-28 also provides a novel molecular mechanism that contributes to the previously recognized link between insulin and TGF-β signaling in C. elegans.

  12. CMOS-compatible dual-output silicon modulator for analog signal processing.

    Science.gov (United States)

    Spector, S J; Geis, M W; Zhou, G-R; Grein, M E; Gan, F; Popovic, M A; Yoon, J U; Lennon, D M; Ippen, E P; Kärtner, F Z; Lyszczarz, T M

    2008-07-21

    A broadband, Mach-Zehnder-interferometer based silicon optical modulator is demonstrated, with an electrical bandwidth of 26 GHz and V(pi)L of 4 V.cm. The design of this modulator does not require epitaxial overgrowth and is therefore simpler to fabricate than previous devices with similar performance.

  13. Morin Attenuates Ovalbumin-Induced Airway Inflammation by Modulating Oxidative Stress-Responsive MAPK Signaling

    Directory of Open Access Journals (Sweden)

    Yuan Ma

    2016-01-01

    Full Text Available Asthma is one of the most common inflammatory diseases characterized by airway hyperresponsiveness, inflammation, and remodeling. Morin, an active ingredient obtained from Moraceae plants, has been demonstrated to have promising anti-inflammatory activities in a range of disorders. However, its impacts on pulmonary diseases, particularly on asthma, have not been clarified. This study was designed to investigate whether morin alleviates airway inflammation in chronic asthma with an emphasis on oxidative stress modulation. In vivo, ovalbumin- (OVA- sensitized mice were administered with morin or dexamethasone before challenge. Bronchoalveolar lavage fluid (BALF and lung tissues were obtained to perform cell counts, histological analysis, and enzyme-linked immunosorbent assay. In vitro, human bronchial epithelial cells (BECs were challenged by tumor necrosis factor alpha (TNF-α. The supernatant was collected for the detection of the proinflammatory proteins, and the cells were collected for reactive oxygen species (ROS/mitogen-activated protein kinase (MAPK evaluations. Severe inflammatory responses and remodeling were observed in the airways of the OVA-sensitized mice. Treatment with morin dramatically attenuated the extensive trafficking of inflammatory cells into the BALF and inhibited their infiltration around the respiratory tracts and vessels. Morin administration also significantly suppressed goblet cell hyperplasia and collagen deposition/fibrosis and dose-dependently inhibited the OVA-induced increases in IgE, TNF-α, interleukin- (IL- 4, IL-13, matrix metalloproteinase-9, and malondialdehyde. In human BECs challenged by TNF-α, the levels of proteins such as eotaxin-1, monocyte chemoattractant protein-1, IL-8 and intercellular adhesion molecule-1, were consistently significantly decreased by morin. Western blotting and the 2′,7′-dichlorofluorescein assay revealed that the increases in intracellular ROS and MAPK phosphorylation were

  14. Yeast product supplementation modulated humoral and mucosal immunity and uterine inflammatory signals in transition dairy cows.

    Science.gov (United States)

    Yuan, K; Mendonça, L G D; Hulbert, L E; Mamedova, L K; Muckey, M B; Shen, Y; Elrod, C C; Bradford, B J

    2015-05-01

    ) in the uterine samples, reflecting greater abundance of these transcripts collected on d 7 compared with d 42. A quadratic dose effect was detected for IL-6, indicating that 30 and 60g/d doses decreased uterine IL-6 mRNA. The mRNA abundance of MPO and ELANE was increased linearly by YC-EHY. Supplementation with YC-EHY enhanced measures of humoral and mucosal immunity and modulated uterine inflammatory signals and mammary gland health in transition dairy cows.

  15. GENERAL: Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator

    Science.gov (United States)

    Liu, Li; Zhang, Liang-Ying; Cao, Li

    2009-10-01

    The diffusion in a harmonic oscillator driven by coloured noises ζ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1) The curves of d versus noise intensity D and d versus noises cross-correlation time τ3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient λ of the two Ornstein-Uhlenbeck (O-U) noises. 2) Changing the value of τ3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3) Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model.

  16. Probability of Error of Linearly Modulated Signals with Gaussian Cochannel Interference in Maximally Correlated Rayleigh Fading Channels

    Directory of Open Access Journals (Sweden)

    Rugini Luca

    2010-01-01

    Full Text Available We evaluate the probability of error of linearly modulated signals, such as phase-shift keying (PSK and quadrature amplitude modulation (QAM, in the presence of Gaussian cochannel interference (CCI and Rayleigh fading channels. Specifically, we assume that the fading channel of the CCI is maximally correlated with the fading channel of the signal of interest (SOI. In practical applications, the maximal correlation of the CCI channel with the SOI channel occurs when the CCI is generated at the transmitter, such as the multiuser interference in downlink systems, or when a transparent repeater relays some thermal noise together with the SOI. We analytically evaluate the error probability by using a series expansion of generalized hypergeometric functions. A convenient truncation criterion is also discussed. The proposed theoretical approach favorably compares with alternative approaches, such as numerical integration and Monte Carlo estimation. Among the various applications of the proposed analysis, we illustrate the effect of nonlinear amplifiers in orthogonal frequency-division multiplexing (OFDM systems, the downlink reception of code-division multiple-access (CDMA signals, and the outdoor-to-indoor relaying of Global Positioning System (GPS signals.

  17. Chiral, J-Aggregate-Forming Dyes for Alternative Signal Modulation Mechanisms in Self-Immolative Enzyme-Activatable Optical Probes.

    Science.gov (United States)

    Sloniec-Myszk, Jagoda; Resch-Genger, Ute; Hennig, Andreas

    2016-02-11

    Enzyme-activatable optical probes are important for future advances in cancer imaging, but may easily suffer from low signal-to-background ratios unless not optimized. To address this shortcoming, numerous mechanisms to modulate the fluorescence signal have been explored. We report herein newly synthesized probes based on self-immolative linkers containing chiral J-aggregate-forming dyes. Signal modulation by formation of chiral J-aggregates is yet unexplored in optical enzyme probe design. The comprehensive characterization of the probes by absorption, CD, fluorescence, and time-resolved fluorescence spectroscopy revealed dye-dye interactions not observed for the free dyes in solution as well as dye-protein interactions with the enzyme. This suggested that J-aggregate formation is challenging to achieve with current probe design and that interactions of the dyes with the enzyme may interfere with achieving high signal-to-background ratios. The detailed understanding of the interactions provided herein provides valuable guidelines for the future design of similar probes.

  18. Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator

    Institute of Scientific and Technical Information of China (English)

    Liu Li; Zhang Liang-Ying; Cao Li

    2009-01-01

    The diffusion in a harmonic oscillator driven by coloured noises ζ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1) The curves of d versus noise intensity D and d versus noises cross-correlation time τ_3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient λ of the two Orustein-Uhlenbeck (O-U) noises. 2) Changing the value of τ3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3)Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model.

  19. Structure-activity relationship studies on acremomannolipin A, the potent calcium signal modulator with a novel glycolipid structure 2: Role of the alditol side chain stereochemistry.

    Science.gov (United States)

    Tsutsui, Nozomi; Tanabe, Genzoh; Gotoh, Genki; Morita, Nao; Nomura, Naohisa; Kita, Ayako; Sugiura, Reiko; Muraoka, Osamu

    2014-02-01

    Five alditol analogs 1b-1f of a novel glycolipid acremomannolipin A (1a), the potential Ca(2+) signal modulator isolated from Acremonium strictum, were synthesized by employing a stereoselective β-mannosylation of appropriately protected mannose with five hexitols with different stereochemistry, and their potential on modulating Ca(2+) signaling were evaluated. All these analogs were more potent compared to the original compound 1a, and proved that mannitol stereochemistry of 1a was not critical for the potent calcium signal modulating.

  20. Spatio-temporal encoding using narrow-band linear frequency modulated signals in synthetic aperture ultrasound imaging

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2005-01-01

    energy, the signal to noise ratio will increase. However, to focus the data properly using the STA approach, the transmitters have to be separated from each other. This is done by dividing the available spectrum into several subbands with a small overlap. Separating different transmitters can be done......, thus, be avoided. To further increase the transmitted energy, the excitation waveforms are designed as linear frequency modulated (FM) signals. This makes it possible to maintain the full excitation amplitude during most of the transmission. The design of the separation filters will also be discussed...... the proposed method achieved approximately 2 cm improvement in penetration depth. The signal to noise ratio was also measured, where the gain was ∼ 7 dB in comparison to the reference....

  1. Digital Filter Design with State Space Method for 1-Bit Signal Processing Based on Delta-Sigma Modulation

    Science.gov (United States)

    Ito, Yuji; Doki, Shinji; Okuma, Sigeru

    1-bit signal processing based on delta-sigma modulation has been studied for hardware implementation of signal processng systems. In the 1-bit signal processing, finite word-length problems such as overflow and coefficent quantization error occur. To solve the problems, new design method with state space is proposed in this paper. Digital filters are designed to show the feasibility of the method. Firstly, L1/L2-sensitivity is shown to evaluate coefficient quantization error and L2 scaling constraints to prevent overflow. Secondly, state space equation is shown and L1/L2-sensitivity and L2-scaling constraints are extended to take filter structure and oversampling effects into account. Finally, the proposed method is shown to attain higher SNR than conventional ones.

  2. Highly active modulators of indole signaling alter pathogenic behaviors in Gram-negative and Gram-positive bacteria.

    Science.gov (United States)

    Minvielle, Marine J; Eguren, Kristen; Melander, Christian

    2013-12-16

    Indole is a universal signal that regulates various bacterial behaviors, such as biofilm formation and antibiotic resistance. To generate mechanistic probes of indole signaling and control indole-mediated pathogenic phenotypes in both Gram-positive and Gram-negative bacteria, we have investigated the use of desformylflustrabromine (dFBr) derivatives to generate highly active indole mimetics. We have developed non-microbicidal dFBr derivatives that are 27-2000 times more active than indole in modulating biofilm formation, motility, acid resistance, and antibiotic resistance. The activity of these analogues parallels indole, because they are dependent on temperature, the enzyme tryptophanase TnaA, and the transcriptional regulator SdiA. This investigation demonstrates that molecules based on the dFBr scaffold can alter pathogenic behaviors by mimicking indole-signaling pathways.

  3. A mixed signal multi-chip module with high speed serial output links for the ATLAS Level-1 trigger

    CERN Document Server

    Pfeiffer, U

    2000-01-01

    We have built and tested a mixed signal multi-chip module (MCM) to be used in the Level-1 Pre-Processor system for the Calorimeter Trigger of the ATLAS experiment at CERN. The MCM performs high speed digital signal processing on four analogue input signals. Results are transmitted serially at a serial data rate of 800 MBd. Nine chips of different technologies are mounted on a four layer Cu substrate. ADC converters and serialiser chips are the major consumers of electrical power on the MCM, which amounts to 9 W for all dies. Special cut-out areas are used to dissipate heat directly to the copper substrate. In this paper we report on design criteria, chosen MCM technology for substrate and die mounting, experiences with the MCM operation and measurement results. (4 refs).

  4. Modulated expression of genes associated with NO signal transduction contributes to the cholesterol-lowering effect of electro-acupuncture.

    Science.gov (United States)

    Li, Ling; Tan, Guang-Hong; Zhang, Yi-Zheng

    2012-07-01

    Electro-acupuncture (EA) at Fenglong acupoint (ST40) can lower the levels of serum cholesterol and triacylglycerols. To study the hepatic genes responsible for the cholesterol-lowering effect of EA, suppression subtractive hybridization combined with the switch mechanism at the 5'-end of RNA template cDNA synthesis and long-distance PCR were employed using hepatic tissues from hypercholesterolemia and EA-treated mice. 68 % of the identified genes are involved in metabolism, immune response, and signal transduction pathways. Real-time PCR and western blot indicate that EA at ST40 induces the expression of nNOS and Mt1, two genes involved in NO signal transduction. EA treatment for hypercholesterolemia thus involves the modulation of several biological pathways and provides a physiological link between NO signal transduction and the cholesterol-lowering effect of EA.

  5. Photo-generated metasurfaces for resonant and high modulation of terahertz signals.

    Science.gov (United States)

    Smaali, R; Taliercio, T; Centeno, E

    2016-08-15

    We theoretically demonstrate resonant modulation of terahertz (THz) waves with photo-designed metasurfaces. Our approach bypasses the short penetration length issue of the optical pump that prevents photo-generated thick metamaterials. We propose a three-layer semiconductor system of subwavelength thickness that presents 100% modulation of the reflection (or absorption) spectra at around 1 THz when optically actuated. This resonant modulation can be dynamically monitored at high frequency by the optical pump on a broad range of frequencies of Δν/ν=100%. Appropriate 2D photo-printed patterns make the system polarization insensitive and operational for a wide range of incident angles up to 65°.

  6. D1 dopamine receptor signaling is modulated by the R7 RGS protein EAT-16 and the R7 binding protein RSBP-1 in Caenoerhabditis elegans motor neurons.

    Directory of Open Access Journals (Sweden)

    Khursheed A Wani

    Full Text Available Dopamine signaling modulates voluntary movement and reward-driven behaviors by acting through G protein-coupled receptors in striatal neurons, and defects in dopamine signaling underlie Parkinson's disease and drug addiction. Despite the importance of understanding how dopamine modifies the activity of striatal neurons to control basal ganglia output, the molecular mechanisms that control dopamine signaling remain largely unclear. Dopamine signaling also controls locomotion behavior in Caenorhabditis elegans. To better understand how dopamine acts in the brain we performed a large-scale dsRNA interference screen in C. elegans for genes required for endogenous dopamine signaling and identified six genes (eat-16, rsbp-1, unc-43, flp-1, grk-1, and cat-1 required for dopamine-mediated behavior. We then used a combination of mutant analysis and cell-specific transgenic rescue experiments to investigate the functional interaction between the proteins encoded by two of these genes, eat-16 and rsbp-1, within single cell types and to examine their role in the modulation of dopamine receptor signaling. We found that EAT-16 and RSBP-1 act together to modulate dopamine signaling and that while they are coexpressed with both D1-like and D2-like dopamine receptors, they do not modulate D2 receptor signaling. Instead, EAT-16 and RSBP-1 act together to selectively inhibit D1 dopamine receptor signaling in cholinergic motor neurons to modulate locomotion behavior.

  7. D1 dopamine receptor signaling is modulated by the R7 RGS protein EAT-16 and the R7 binding protein RSBP-1 in Caenoerhabditis elegans motor neurons.

    Science.gov (United States)

    Wani, Khursheed A; Catanese, Mary; Normantowicz, Robyn; Herd, Muriel; Maher, Kathryn N; Chase, Daniel L

    2012-01-01

    Dopamine signaling modulates voluntary movement and reward-driven behaviors by acting through G protein-coupled receptors in striatal neurons, and defects in dopamine signaling underlie Parkinson's disease and drug addiction. Despite the importance of understanding how dopamine modifies the activity of striatal neurons to control basal ganglia output, the molecular mechanisms that control dopamine signaling remain largely unclear. Dopamine signaling also controls locomotion behavior in Caenorhabditis elegans. To better understand how dopamine acts in the brain we performed a large-scale dsRNA interference screen in C. elegans for genes required for endogenous dopamine signaling and identified six genes (eat-16, rsbp-1, unc-43, flp-1, grk-1, and cat-1) required for dopamine-mediated behavior. We then used a combination of mutant analysis and cell-specific transgenic rescue experiments to investigate the functional interaction between the proteins encoded by two of these genes, eat-16 and rsbp-1, within single cell types and to examine their role in the modulation of dopamine receptor signaling. We found that EAT-16 and RSBP-1 act together to modulate dopamine signaling and that while they are coexpressed with both D1-like and D2-like dopamine receptors, they do not modulate D2 receptor signaling. Instead, EAT-16 and RSBP-1 act together to selectively inhibit D1 dopamine receptor signaling in cholinergic motor neurons to modulate locomotion behavior.

  8. Human glutathione S-transferase P1-1 functions as an estrogen receptor α signaling modulator

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiyuan [Department of Biological Science, Sookmyung Women’s University, Seoul (Korea, Republic of); An, Byoung Ha [Department of Food and Nutrition, College of Life Science, Sookmyung Women’s University, Seoul (Korea, Republic of); Kim, Min Jung; Park, Jong Hoon [Department of Biological Science, Sookmyung Women’s University, Seoul (Korea, Republic of); Kang, Young Sook [Department of Pharmacy, College of Pharmacy, Sookmyung Women’s University, Seoul (Korea, Republic of); Chang, Minsun, E-mail: minsunchang@sm.ac.kr [Department of Medical and Pharmaceutical Science, College of Science, Sookmyung Women’s University, Seoul (Korea, Republic of)

    2014-09-26

    Highlights: • GSTP induces the classical ERα signaling event. • The functional GSTP is a prerequisite for GSTP-induced ERα transcription activity. • The expression of RIP140, a transcription cofactor, was inhibited by GSTP protein. • We propose the novel non-enzymatic role of GSTP. - Abstract: Estrogen receptor α (ERα) plays a crucial role in estrogen-mediated signaling pathways and exerts its action as a nuclear transcription factor. Binding of the ligand-activated ERα to the estrogen response element (ERE) is a central part of ERα-associated signal transduction pathways and its aberrant modulation is associated with many disease conditions. Human glutathione S-transferase P1-1 (GSTP) functions as an enzyme in conjugation reactions in drug metabolism and as a regulator of kinase signaling pathways. It is overexpressed in tumors following chemotherapy and has been associated with a poor prognosis in breast cancer. In this study, a novel regulatory function of GSTP has been proposed in which GSTP modulates ERE-mediated ERα signaling events. Ectopic expression of GSTP was able to induce the ERα and ERE-mediated transcriptional activities in ERα-positive but GSTP-negative MCF7 human breast cancer cells. This inductive effect of GSTP on the ERE-transcription activity was diminished when the cells express a mutated form of the enzyme or are treated with a GSTP-specific chemical inhibitor. It was found that GSTP inhibited the expression of the receptor interacting protein 140 (RIP140), a negative regulator of ERα transcription, at both mRNA and protein levels. Our study suggests a novel non-enzymatic role of GSTP which plays a significant role in regulating the classical ERα signaling pathways via modification of transcription cofactors such as RIP140.

  9. Cortical axons, isolated in channels, display activity-dependent signal modulation as a result of targeted stimulation

    Directory of Open Access Journals (Sweden)

    Marta K. Lewandowska

    2016-03-01

    Full Text Available Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10-20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 Hz up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells’ signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for many different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations.

  10. Histamine derived from probiotic Lactobacillus reuteri suppresses TNF via modulation of PKA and ERK signaling.

    NARCIS (Netherlands)

    Thomas, C.M.G.; Hong, T.; Pijkeren, J.P. van; Hemarajata, P.; Trinh, D.V.; Hu, W.; Britton, R.A.; Kalkum, M.; Versalovic, J.

    2012-01-01

    Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was

  11. Bacterial sensing, cell signaling, and modulation of the immune response during sepsis

    National Research Council Canada - National Science Library

    Salomao, Reinaldo; Brunialti, Milena Karina Colo; Rapozo, Marjorie Marini; Baggio-Zappia, Giovana Lotici; Galanos, Chris; Freudenberg, Marina

    2012-01-01

    ...) gene, implications of innate immune cells as drivers of the adaptive response to infection, and the modulation of multiple accessory molecules that stimulate or inhibit monocyte/macrophage and lymphocyte interactions...

  12. Noise signals and carrier modulation arising in electrical cables during nuclear pulse irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Both, E.; Bruemmer, H. P.; Lascaro, C. P.; Newberg, J.; Schlosser, W.

    1963-03-15

    Electrical noise signals generated in coaxial and other cables by pulsed nuclear radiation were measured as a function of applied voltage and exposure history. In consecutive exposures the signal magnitude and polarity was found to be strongly affected by training and memory effects. Unexpectedly large signals in the cable shield were identified as the cause for oscillatory signals in the center conductor and for the occurrence of parasitic leakage currents in nearby conductors. A r-f signal transmitted through RG62 A/U cable undergoes a temporary attenuation during the radiation pulse while it passes through RG59 B/U without measurable degradation. Definite rules are given for minimizing cable noise signals in nuclear pulse radiation measurements. (auth)

  13. Nonsteroidal anti-inflammatory drugs modulate cellular glycosaminoglycan synthesis by affecting EGFR and PI3K signaling pathways

    Science.gov (United States)

    Mozolewski, Paweł; Moskot, Marta; Jakóbkiewicz-Banecka, Joanna; Węgrzyn, Grzegorz; Bocheńska, Katarzyna; Banecki, Bogdan; Gabig-Cimińska, Magdalena

    2017-01-01

    In this report, selected non-steroidal anti-inflammatory drugs (NSAIDs), indomethacin and nimesulide, and analgesics acetaminophen, alone, as well as in combination with isoflavone genistein as potential glycosaminoglycan (GAG) metabolism modulators were considered for the treatment of mucopolysaccharidoses (MPSs) with neurological symptoms due to the effective blood-brain barrier (BBB) penetration properties of these compounds. We found that indomethacin and nimesulide, but not acetaminophen, inhibited GAG synthesis in fibroblasts significantly, while the most pronounced impairment of glycosaminoglycan production was observed after exposure to the mixture of nimesulide and genistein. Phosphorylation of the EGF receptor (EGFR) was inhibited even more effective in the presence of indomethacin and nimesulide than in the presence of genistein. When examined the activity of phosphatidylinositol-3-kinase (PI3K) production, we observed its most significant decrease in the case of fibroblast exposition to nimesulide, and afterwards to indomethacin and genistein mix, rather than indomethacin used alone. Some effects on expression of individual GAG metabolism-related and lysosomal function genes, and significant activity modulation of a number of genes involved in intracellular signal transduction pathways and metabolism of DNA and proteins were detected. This study documents that NSAIDs, and their mixtures with genistein modulate cellular glycosaminoglycan synthesis by affecting EGFR and PI3K signaling pathways. PMID:28240227

  14. Receiver Signal to Noise Ratios for IPDA Lidars Using Sine-wave and Pulsed Laser Modulation and Direct Detections

    Science.gov (United States)

    Sun, Xiaoli; Abshire, James B.

    2011-01-01

    Integrated path differential absorption (IPDA) lidar can be used to remotely measure the column density of gases in the path to a scattering target [1]. The total column gas molecular density can be derived from the ratio of the laser echo signal power with the laser wavelength on the gas absorption line (on-line) to that off the line (off-line). 80th coherent detection and direct detection IPDA lidar have been used successfully in the past in horizontal path and airborne remote sensing measurements. However, for space based measurements, the signal propagation losses are often orders of magnitude higher and it is important to use the most efficient laser modulation and detection technique to minimize the average laser power and the electrical power from the spacecraft. This paper gives an analysis the receiver signal to noise ratio (SNR) of several laser modulation and detection techniques versus the average received laser power under similar operation environments. Coherent detection [2] can give the best receiver performance when the local oscillator laser is relatively strong and the heterodyne mixing losses are negligible. Coherent detection has a high signal gain and a very narrow bandwidth for the background light and detector dark noise. However, coherent detection must maintain a high degree of coherence between the local oscillator laser and the received signal in both temporal and spatial modes. This often results in a high system complexity and low overall measurement efficiency. For measurements through atmosphere the coherence diameter of the received signal also limits the useful size of the receiver telescope. Direct detection IPDA lidars are simpler to build and have fewer constraints on the transmitter and receiver components. They can use much larger size 'photon-bucket' type telescopes to reduce the demands on the laser transmitter. Here we consider the two most widely used direct detection IPDA lidar techniques. The first technique uses two CW

  15. ß-Adrenergic Receptor Signaling and Modulation of Long-Term Potentiation in the Mammalian Hippocampus

    Science.gov (United States)

    O'Dell, Thomas J.; Connor, Steven A.; Guglietta, Ryan; Nguyen, Peter V.

    2015-01-01

    Encoding new information in the brain requires changes in synaptic strength. Neuromodulatory transmitters can facilitate synaptic plasticity by modifying the actions and expression of specific signaling cascades, transmitter receptors and their associated signaling complexes, genes, and effector proteins. One critical neuromodulator in the…

  16. Bone morphogenetic protein 2 signaling negatively modulates lymphatic development in vertebrate embryos

    DEFF Research Database (Denmark)

    Dunworth, William P; Cardona-Costa, Jose; Bozkulak, Esra Cagavi

    2014-01-01

    signaling in zebrafish embryos and mouse embryonic stem cell-derived embryoid bodies substantially decrease the emergence of LECs. Mechanistically, BMP2 signaling induces expression of miR-31 and miR-181a in a SMAD-dependent mechanism, which in turn results in attenuated expression of prospero homeobox...

  17. The method of «blind» carrier frequency estimation of radio signals with linear digital modulation

    Directory of Open Access Journals (Sweden)

    Nahornyuk О.А.

    2017-04-01

    Full Text Available Carrier frequency estimation in the conditions of a priori uncertainty of signal modulation and parameters is prerequisite for realization of frequency synchronization circuits in software-defined radio. To implement this operation the method of «blind» carrier frequency estimation of radio signals with amplitude, phase and quadrature-amplitude shift keying, which does not require prior information about modulation type, signal and communication channel parameters, is proposed in the article. The basis of method is calculation of constellation symbols cross-correlation and clock synchronization by Gardner method. As opposed to known approaches proposed method does not require two-dimensional objective function calculation which can reduce the number of computing operations. This is achieved by implementation of previous clock synchronization and reducing the two-dimensional objective function in one-dimensional. Verification of developed method is carried out by statistical modeling using more than 20 types of phase constellations. The practical significance of received results consists in reduction of carrier frequency estimation time and simplification of practical implementation at the expense of employment of approved clock synchronization circuits.

  18. SIZ1-Dependent Post-Translational Modification by SUMO Modulates Sugar Signaling and Metabolism in Arabidopsis thaliana.

    Science.gov (United States)

    Castro, Pedro Humberto; Verde, Nuno; Lourenço, Tiago; Magalhães, Alexandre Papadopoulos; Tavares, Rui Manuel; Bejarano, Eduardo Rodríguez; Azevedo, Herlânder

    2015-12-01

    Post-translational modification mechanisms function as switches that mediate the balance between optimum growth and the response to environmental stimuli, by regulating the activity of key proteins. SUMO (small ubiquitin-like modifier) attachment, or sumoylation, is a post-translational modification that is essential for the plant stress response, also modulating hormonal circuits to co-ordinate developmental processes. The Arabidopsis SUMO E3 ligase SAP and Miz 1 (SIZ1) is the major SUMO conjugation enhancer in response to stress, and is implicated in several aspects of plant development. Here we report that known SUMO targets are over-represented in multiple carbohydrate-related proteins, suggesting a functional link between sumoylation and sugar metabolism and signaling in plants. We subsequently observed that SUMO-conjugated proteins accumulate in response to high doses of sugar in a SIZ1-dependent manner, and that the null siz1 mutant displays increased expression of sucrose and starch catabolic genes and shows reduced starch levels. We demonstrated that SIZ1 controls germination time and post-germination growth via osmotic and sugar-dependent signaling, respectively. Glucose was specifically linked to SUMO-sugar interplay, with high levels inducing root growth inhibition and aberrant root hair morphology in siz1. The use of sugar analogs and sugar marker gene expression analysis allowed us to implicate SIZ1 in a signaling pathway dependent on glucose metabolism, probably involving modulation of SNF1-related kinase 1 (SnRK1) activity.

  19. Demonstration of DFT-spread 256QAM-OFDM signal transmission with cost-effective directly modulated laser.

    Science.gov (United States)

    Li, Fan; Yu, Jianjun; Fang, Yuan; Dong, Ze; Li, Xinying; Chen, Lin

    2014-04-07

    We experimentally demonstrated a 256-ary quadrature amplitude modulation (256QAM) direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) transmission system utilizing a cost-effective directly modulated laser (DML). Intra-symbol frequency-domain averaging (ISFA) is applied to suppress in-band noise while the channel response estimation and Discrete Fourier Transform-spread (DFT-spread) is used to reduce the peak-to-average power ratio (PAPR) of the transmitted OFDM signal. The bit-error ratio (BER) of 15-Gbit/s 256QAM-OFDM signal has been measured after 20-km SSMF transmission that is less than 7% forward-error-correction (FEC) threshold of 3.8 × 10(-3) as the launch power into fiber is set at 6dBm. For 11.85-Gbit/s 256QAM-OFDM signal, with the aid of ISFA-based channel estimation and PAPR reduction enabled by DFT-spread, the BER after 20-km SSMF transmission can be improved from 6.4 × 10(-3) to 6.8 × 10(-4) when the received optical power is -6dBm.

  20. Method for signal decomposition and denoising based on nonuniform cosine-modulated filter banks

    Institute of Scientific and Technical Information of China (English)

    Xuemei Xie; Li Li; Guangming Shi; Bin Peng

    2008-01-01

    In this paper,a novel method for signal decomposition and denoising is proposed based on a nonuniform filter bank (NUFB),which is derived from a uniform filter bank.With this method,the signal is firstly decomposed into M subbands using a uniform filter bank.Then according to their energy distribution,the corresponding consecutive filters are merged to compose the nonuniform filters.With the resulting NUFB,the signal can be readily matched and flexibly decomposed according to its power spectrum distribution.As another advantage,this method can be used to detect and remove the narrow-band noise from the corrupted signal.To verify the proposed method,a simulation of extracting the main information of an audio signal and removing its glitch is given.

  1. G protein modulation of recombinant P/Q-type calcium channels by regulators of G protein signalling proteins.

    Science.gov (United States)

    Mark, M D; Wittemann, S; Herlitze, S

    2000-10-01

    1. Fast synaptic transmission is triggered by the activation of presynaptic Ca2+ channels which can be inhibited by Gbetagamma subunits via G protein-coupled receptors (GPCR). Regulators of G protein signalling (RGS) proteins are GTPase-accelerating proteins (GAPs), which are responsible for >100-fold increases in the GTPase activity of G proteins and might be involved in the regulation of presynaptic Ca2+ channels. In this study we investigated the effects of RGS2 on G protein modulation of recombinant P/Q-type channels expressed in a human embryonic kidney (HEK293) cell line using whole-cell recordings. 2. RGS2 markedly accelerates transmitter-mediated inhibition and recovery from inhibition of Ba2+ currents (IBa) through P/Q-type channels heterologously expressed with the muscarinic acetylcholine receptor M2 (mAChR M2). 3. Both RGS2 and RGS4 modulate the prepulse facilitation properties of P/Q-type Ca2+ channels. G protein reinhibition is accelerated, while release from inhibition is slowed. These kinetics depend on the availability of G protein alpha and betagamma subunits which is altered by RGS proteins. 4. RGS proteins unmask the Ca2+ channel beta subunit modulation of Ca2+ channel G protein inhibition. In the presence of RGS2, P/Q-type channels containing the beta2a and beta3 subunits reveal significantly altered kinetics of G protein modulation and increased facilitation compared to Ca2+ channels coexpressed with the beta1b or beta4 subunit.

  2. Analysis of Maneuvering Targets with Complex Motions by Two-Dimensional Product Modified Lv's Distribution for Quadratic Frequency Modulation Signals.

    Science.gov (United States)

    Jing, Fulong; Jiao, Shuhong; Hou, Changbo; Si, Weijian; Wang, Yu

    2017-06-21

    For targets with complex motion, such as ships fluctuating with oceanic waves and high maneuvering airplanes, azimuth echo signals can be modeled as multicomponent quadratic frequency modulation (QFM) signals after migration compensation and phase adjustment. For the QFM signal model, the chirp rate (CR) and the quadratic chirp rate (QCR) are two important physical quantities, which need to be estimated. For multicomponent QFM signals, the cross terms create a challenge for detection, which needs to be addressed. In this paper, by employing a novel multi-scale parametric symmetric self-correlation function (PSSF) and modified scaled Fourier transform (mSFT), an effective parameter estimation algorithm is proposed-referred to as the Two-Dimensional product modified Lv's distribution (2D-PMLVD)-for QFM signals. The 2D-PMLVD is simple and can be easily implemented by using fast Fourier transform (FFT) and complex multiplication. These measures are analyzed in the paper, including the principle, the cross term, anti-noise performance, and computational complexity. Compared to the other three representative methods, the 2D-PMLVD can achieve better anti-noise performance. The 2D-PMLVD, which is free of searching and has no identifiability problems, is more suitable for multicomponent situations. Through several simulations and analyses, the effectiveness of the proposed estimation algorithm is verified.

  3. Modeling of the lower ionospheric response and VLF signal modulation during a total solar eclipse using ionospheric chemistry and LWPC

    Science.gov (United States)

    Chakraborty, Suman; Palit, Sourav; Ray, Suman; Chakrabarti, Sandip K.

    2016-02-01

    The variation in the solar Extreme Ultraviolet (EUV) radiation flux by any measure is the most dominant natural source to produce perturbations or modulations in the ionospheric chemical and plasma properties. A solar eclipse, though a very rare phenomenon, is similarly bound to produce a significant short time effect on the local ionospheric properties. The influence of the ionizing solar flux reduction during a solar eclipse on the lower ionosphere or, more precisely, the D-region, can be studied with the observation of Very Low Frequency (VLF) radio wave signal modulation. The interpretation of such an effect on VLF signals requires a knowledge of the D-region ion chemistry, which is not well studied till date. Dominant parameters which govern the ion chemistry, such as the recombination coefficients, are poorly known. The occurrence of events such as a solar eclipse provides us with an excellent opportunity to investigate the accuracy of our knowledge of the chemical condition in this part of Earth's atmosphere and the properties which control the ionospheric stability under such disturbances. In this paper, using existing knowledge of the lower ionospheric chemical and physical properties we carry out an interpretation of the effects obtained during the total solar eclipse of 22 of July 2009 on the VLF signal. Data obtained from a week long campaign conducted by the Indian Centre for Space Physics (ICSP) over the Indian subcontinent has been used for this purpose. Both positive and negative amplitude changes during the eclipse were observed along various receiver locations. In this paper, data for a propagation path between a Indian Navy VLF transmitter named VTX3 and a pair of receivers in India are used. We start from the observed solar flux during the eclipse and calculate the ionization during the whole time span over most of the influenced region in a range of height. We incorporate a D-region ion-chemistry model to find the equilibrium ion density over

  4. Few-View Prereconstruction Guided Tube Current Modulation Strategy Based on the Signal-to-Noise Ratio of the Sinogram

    Directory of Open Access Journals (Sweden)

    Ming Chang

    2015-01-01

    Full Text Available The radiation dose reduction without sacrificing the image quality as an important issue has raised the attention of CT manufacturers and different automatic exposure control (AEC strategies have been adopted in their products. In this paper, we focus on the strategy of tube current modulation. It is deduced based on the signal-to-noise (SNR of the sinogram. The main idea behind the proposed modulation strategy is to keep the SNR of the sinogram proximately invariable using the few-view reconstruction as a good reference because it directly affects the noise level of the reconstructions. The numerical experiment results demonstrate that, compared with constant tube current, the noise distribution is more uniform and the SNR and CNR of the reconstruction are better when the proposed strategy is applied. Furthermore it has the potential to distinguish the low-contrast target and to reduce the radiation dose.

  5. Nonlinear impairment compensation for DFT-S OFDM signal transmission with directly modulated laser and direct detection

    Science.gov (United States)

    Gou, Pengqi; Wang, Kaihui; Qin, Chaoyi; Yu, Jianjun

    2017-03-01

    We experimentally demonstrate a 16-ary quadrature amplitude modulation (16QAM) DFT-spread optical orthogonal frequency division multiplexing (OFDM) transmission system utilizing a cost-effective directly modulated laser (DML) and direct detection. For 20-Gbaud 16QAM-OFDM signal, with the aid of nonlinear equalization (NLE) algorithm, we respectively provide 6.2-dB and 5.2-dB receiver sensitivity improvement under the hard-decision forward-error-correction (HD-FEC) threshold of 3.8×10-3 for the back-to-back (BTB) case and after transmission over 10-km standard single mode fiber (SSMF) case, related to only adopt post-equalization scheme. To our knowledge, this is the first time to use dynamic nonlinear equalizer (NLE) based on the summation of the square of the difference between samples in one IM/DD OFDM system with DML to mitigate nonlinear distortion.

  6. Isolation of Positive Modulator of Glucagon-like Peptide-1 Signaling from Trigonella foenum-graecum (Fenugreek) Seed.

    Science.gov (United States)

    King, Klim; Lin, Nai-Pin; Cheng, Yu-Hong; Chen, Gao-Hui; Chein, Rong-Jie

    2015-10-23

    The glucagon-like peptide-1 receptor (GLP-1R) is expressed in many tissues and has been implicated in diverse physiological functions, such as energy homeostasis and cognition. GLP-1 analogs are approved for treatment of type 2 diabetes and are undergoing clinical trials for other disorders, including neurodegenerative diseases. GLP-1 analog therapies maintain chronically high plasma levels of the analog and can lead to loss of spatiotemporal control of GLP-1R activation. To avoid adverse effects associated with current therapies, we characterized positive modulators of GLP-1R signaling. We screened extracts from edible plants using an intracellular cAMP biosensor and GLP-1R endocytosis assays. Ethanol extracts from fenugreek seeds enhanced GLP-1 signaling. These seeds have previously been found to reduce glucose and glycated hemoglobin levels in humans. An active compound (N55) with a new N-linoleoyl-2-amino-γ-butyrolactone structure was purified from fenugreek seeds. N55 promoted GLP-1-dependent cAMP production and GLP-1R endocytosis in a dose-dependent and saturable manner. N55 specifically enhanced GLP-1 potency more than 40-fold, but not that of exendin 4, to stimulate cAMP production. In contrast to the current allosteric modulators that bind to GLP-1R, N55 binds to GLP-1 peptide and facilitates trypsin-mediated GLP-1 inactivation. These findings identify a new class of modulators of GLP-1R signaling and suggest that GLP-1 might be a viable target for drug discovery. Our results also highlight a feasible approach for screening bioactive activity of plant extracts.

  7. Use of modulated excitation signals in ultrasound. Part II: Design and performance for medical imaging applications

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    For pt.I, see ibid., vol.52, no.2, p.177-91 (2005). In the first paper, the superiority of linear FM signals was shown in terms of signal-to-noise ratio and robustness to tissue attenuation. This second paper in the series of three papers on the application of coded excitation signals in medical...... ultrasound presents design methods of linear FM signals and mismatched filters, in order to meet the higher demands on resolution in ultrasound imaging. It is shown that for the small time-bandwidth (TB) products available in ultrasound, the rectangular spectrum approximation is not valid, which reduces...... to efficiently use the available bandwidth and at the same time to be insensitive to the transducer's impulse response. With these techniques, temporal sidelobes are kept below 60 to 100 dB, image contrast is improved by reducing the energy within the sidelobe region, and axial resolution is preserved...

  8. Membrane potential modulates plasma membrane phospholipid dynamics and K-Ras signaling

    Science.gov (United States)

    Zhou, Yong; Wong, Ching-On; Cho, Kwang-jin; van der Hoeven, Dharini; Liang, Hong; Thakur, Dhananiay P.; Luo, Jialie; Babic, Milos; Zinsmaier, Konrad E.; Zhu, Michael X.; Hu, Hongzhen; Venkatachalam, Kartik; Hancock, John F.

    2015-01-01

    Plasma membrane depolarization can trigger cell proliferation, but how membrane potential influences mitogenic signaling is uncertain. Here, we show that plasma membrane depolarization induces nanoscale reorganization of phosphatidylserine and phosphatidylinositol 4,5-bisphosphate but not other anionic phospholipids. K-Ras, which is targeted to the plasma membrane by electrostatic interactions with phosphatidylserine, in turn undergoes enhanced nanoclustering. Depolarization-induced changes in phosphatidylserine and K-Ras plasma membrane organization occur in fibroblasts, excitable neuroblastoma cells, and Drosophila neurons in vivo and robustly amplify K-Ras–dependent mitogen-activated protein kinase (MAPK) signaling. Conversely, plasma membrane repolarization disrupts K-Ras nanoclustering and inhibits MAPK signaling. By responding to voltage-induced changes in phosphatidylserine spatiotemporal dynamics, K-Ras nanoclusters set up the plasma membrane as a biological field-effect transistor, allowing membrane potential to control the gain in mitogenic signaling circuits. PMID:26293964

  9. Co-modulation of WDM-FDM WiMAX-FM and IEEE802.11ac signals by DFB-LD and MZM

    Science.gov (United States)

    Teruya, Miku; Chinen, Koyu

    2017-07-01

    We have investigated how wavelength spacing and frequency spacing in WDM (Wavelength Division Multiplexing) and FDM (Frequency Division Multiplexing) using direct modulation lasers (DML) and external modulators of Mach-Zehnder Modulator (MZM) affect optical and electrical interferences. Two signals of 4.8GHz-64QAM-5MHzBW WiMAX and 4.7GHz-32MHzBW FM were directly modulated with uncooled 1550nm DFB-LDs, and 5GHz-256QAM-80MHzBW IEEE802.11ac signal was modulated on the combined optical signals of WiMAX and FM at an MZM. Change in RCE of the WiMAX signal and EVM of the IEEE 802.11ac signal were measured when the wavelength spacing between two DFB-LDs was varied. When the wavelength spacing was larger than 0.05 nm and the ratio of peak to bottom of optical power was larger than 30 dB, the RCE of WiMAX signal was decreased to lower than -20dB. The WDM using directly modulated DFB-LDs and MZM was realized, when the wavelength spacing was larger than 0.1 nm and the peak to bottom ratio of optical power was larger than 60 dB, since the EVM of IEEE802.11ac signal was decreased to around -30dB. The FDM with the same configuration as that of the WDM was realized, when the frequency spacing was larger than a half of the sum of the BWs of WiMAX and FM signals, as the RCE of WiMAX signal decreased to lower than -35 dB and the EVM of IEEE802.11ac signal decreased to around -30dB.

  10. Clock recovery PLL with gated PFD for NRZ ON-OFF Modulated Signals in a retinal implant system.

    Science.gov (United States)

    Brendler, Christian; Aryan, Naser Pour; Rieger, Viola; Rothermel, Albrecht

    2013-01-01

    A Clock Recovery Phase Locked Loop with Gated Phase Frequency Detector (GPLL) for NRZ ON-OFF Modulated Signals with low data transmission rates for an inductively powered subretinal implant system is presented. Low data transmission rate leads to a long absence of inductive powering in the system when zeros are transmitted. Consequently there is no possibility to extract any clock in these pauses, thus the digital circuitry can not work any more. Compared to a commonly used PLL for clock extraction, no certain amount of data transitions is needed. This is achieved by having two operating modes. In one mode the GPLL tracks the HF input signal. In the other, the GPLL is an adjustable oscillator oscillating at the last used frequency. The proposed GPLL is fabricated and measured using a 350 nm High Voltage CMOS technology.

  11. Signaling and Adaptation Modulate the Dynamics of the Photosensoric Complex of Natronomonas pharaonis.

    Directory of Open Access Journals (Sweden)

    Philipp S Orekhov

    2015-10-01

    Full Text Available Motile bacteria and archaea respond to chemical and physical stimuli seeking optimal conditions for survival. To this end transmembrane chemo- and photoreceptors organized in large arrays initiate signaling cascades and ultimately regulate the rotation of flagellar motors. To unravel the molecular mechanism of signaling in an archaeal phototaxis complex we performed coarse-grained molecular dynamics simulations of a trimer of receptor/transducer dimers, namely NpSRII/NpHtrII from Natronomonas pharaonis. Signaling is regulated by a reversible methylation mechanism called adaptation, which also influences the level of basal receptor activation. Mimicking two extreme methylation states in our simulations we found conformational changes for the transmembrane region of NpSRII/NpHtrII which resemble experimentally observed light-induced changes. Further downstream in the cytoplasmic domain of the transducer the signal propagates via distinct changes in the dynamics of HAMP1, HAMP2, the adaptation domain and the binding region for the kinase CheA, where conformational rearrangements were found to be subtle. Overall these observations suggest a signaling mechanism based on dynamic allostery resembling models previously proposed for E. coli chemoreceptors, indicating similar properties of signal transduction for archaeal photoreceptors and bacterial chemoreceptors.

  12. Modulation of Macrophage Inflammatory Nuclear Factor κB (NF-κB) Signaling by Intracellular Cryptococcus neoformans.

    Science.gov (United States)

    Hayes, James B; Sircy, Linda M; Heusinkveld, Lauren E; Ding, Wandi; Leander, Rachel N; McClelland, Erin E; Nelson, David E

    2016-07-22

    Cryptococcus neoformans (Cn) is a common facultative intracellular pathogen that can cause life-threatening fungal meningitis in immunocompromised individuals. Shortly after infection, Cn is detectable as both extra- and intracellular yeast particles, with Cn being capable of establishing long-lasting latent infections within host macrophages. Although recent studies have shown that shed capsular polysaccharides and intact extracellular Cn can compromise macrophage function through modulation of NF-κB signaling, it is currently unclear whether intracellular Cn also affects NF-κB signaling. Utilizing live cell imaging and computational modeling, we find that extra- and intracellular Cn support distinct modes of NF-κB signaling in cultured murine macrophages. Specifically, in RAW 264.7 murine macrophages treated with extracellular glucuronoxylomannan (GXM), the major Cn capsular polysaccharide, LPS-induced nuclear translocation of p65 is inhibited, whereas in cells with intracellular Cn, LPS-induced nuclear translocation of p65 is both amplified and sustained. Mathematical simulations and quantification of nascent protein expression indicate that this is a possible consequence of Cn-induced "translational interference," impeding IκBα resynthesis. We also show that long term Cn infection induces stable nuclear localization of p65 and IκBα proteins in the absence of additional pro-inflammatory stimuli. In this case, nuclear localization of p65 is not accompanied by TNFα or inducible NOS (iNOS) expression. These results demonstrate that capsular polysaccharides and intact intracellular yeast manipulate NF-κB via multiple distinct mechanisms and provide new insights into how Cn might modulate cellular signaling at different stages of an infection.

  13. Long-Term Expansion, Enhanced Chondrogenic Potential, and Suppression of Endochondral Ossification of Adult Human MSCs via WNT Signaling Modulation

    Directory of Open Access Journals (Sweden)

    Roberto Narcisi

    2015-03-01

    Full Text Available Mesenchymal stem cells (MSCs are a potential source of chondrogenic cells for the treatment of cartilage disorders, but loss of chondrogenic potential during in vitro expansion and the propensity of cartilage to undergo hypertrophic maturation impede their therapeutic application. Here we report that the signaling protein WNT3A, in combination with FGF2, supports long-term expansion of human bone marrow-derived MSCs. The cells retained their chondrogenic potential and other phenotypic and functional properties of multipotent MSCs, which were gradually lost in the absence of WNT3A. Moreover, we discovered that endogenous WNT signals are the main drivers of the hypertrophic maturation that follows chondrogenic differentiation. Inhibition of WNT signals during differentiation prevented calcification and maintained cartilage properties following implantation in a mouse model. By maintaining potency during expansion and preventing hypertrophic maturation following differentiation, the modulation of WNT signaling removes two major obstacles that impede the clinical application of MSCs in cartilage repair.

  14. Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

    Directory of Open Access Journals (Sweden)

    M. Platino

    2004-07-01

    Full Text Available It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and high-altitude satellite observations have also been reported (James et al., 1990. One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere illuminated by the ELF/VLF waves. In an attempt to investigate this question further, ground-satellite conjunction experiments have recently been conducted using the four Cluster satellites and the HF heater of the High-Frequency Active Auroral Research Program (HAARP facility in Gakona, Alaska. Being located on largely closed field lines at L≈4.9, HAARP is currently also being used for ground-to-ground type of ELF/VLF wave-injection experiments, and will be increasingly used for this purpose as it is now being upgraded for higher power operation. In this paper, we describe the HAARP installation and present recent results of the HAARP-Cluster experiments. We give an overview of the detected ELF/VLF signals at Cluster, and a possible explanation of the spectral signature detected, as well as the determination of the location of the point of injection of the HAARP ELF/VLF signals into the magnetosphere using ray tracing.

  15. Ultralow-phase-noise millimetre-wave signal generator assisted with an electro-optics-modulator-based optical frequency comb.

    Science.gov (United States)

    Ishizawa, A; Nishikawa, T; Goto, T; Hitachi, K; Sogawa, T; Gotoh, H

    2016-05-17

    Low-noise millimetre-wave signals are valuable for digital sampling systems, arbitrary waveform generation for ultra-wideband communications, and coherent radar systems. However, the phase noise of widely used conventional signal generators (SGs) will increase as the millimetre-wave frequency increases. Our goal has been to improve commercially available SGs so that they provide a low-phase-noise millimetre-wave signal with assistance from an electro-optics-modulator-based optical frequency comb (EOM-OFC). Here, we show that the phase noise can be greatly reduced by bridging the vast frequency difference between the gigahertz and terahertz ranges with an EOM-OFC. The EOM-OFC serves as a liaison that magnifies the phase noise of the SG. With the EOM-OFC used as a phase noise "booster" for a millimetre-wave signal, the phase noise of widely used SGs can be reduced at an arbitrary frequency f (6 ≦ f ≦ 72 GHz).

  16. Experimental investigation of saturation effect on pump-to-signal intensity modulation transfer in single-pump phase-insensitive fiber optic parametric amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke

    2013-01-01

    We present an experimental characterization of how signal gain saturation affects the transfer of intensity modulation from the pump to the signal in single-pump, phase-insensitive fiber optic parametric amplifiers (FOPAs). In this work, we demonstrate experimentally for the first time, to our...

  17. Intensity-dependent modulation of optically active signals in a chiral metamaterial

    Science.gov (United States)

    Rodrigues, Sean P.; Lan, Shoufeng; Kang, Lei; Cui, Yonghao; Panuski, Patrick W.; Wang, Shengxiang; Urbas, Augustine M.; Cai, Wenshan

    2017-01-01

    Chiral media exhibit optical phenomena that provide distinctive responses from opposite circular polarizations. The disparity between these responses can be optimized by structurally engineering absorptive materials into chiral nanopatterns to form metamaterials that provide gigantic chiroptical resonances. To fully leverage the innate duality of chiral metamaterials for future optical technologies, it is essential to make such chiroptical responses tunable via external means. Here we report an optical metamaterial with tailored chiroptical effects in the nonlinear regime, which exhibits a pronounced shift in its circular dichroism spectrum under a modest level of excitation power. Strong nonlinear optical rotation is observed at key spectral locations, with an intensity-induced change of 14° in the polarization rotation from a metamaterial thickness of less than λ/7. The modulation of chiroptical responses by manipulation of input powers incident on chiral metamaterials offers potential for active optics such as all-optical switching and light modulation. PMID:28240288

  18. Resveratrol modulates the inflammatory response via an estrogen receptor-signal integration network

    Science.gov (United States)

    Nwachukwu, Jerome C; Srinivasan, Sathish; Bruno, Nelson E; Parent, Alexander A; Hughes, Travis S; Pollock, Julie A; Gjyshi, Olsi; Cavett, Valerie; Nowak, Jason; Garcia-Ordonez, Ruben D; Houtman, René; Griffin, Patrick R; Kojetin, Douglas J; Katzenellenbogen, John A; Conkright, Michael D; Nettles, Kendall W

    2014-01-01

    Resveratrol has beneficial effects on aging, inflammation and metabolism, which are thought to result from activation of the lysine deacetylase, sirtuin 1 (SIRT1), the cAMP pathway, or AMP-activated protein kinase. In this study, we report that resveratrol acts as a pathway-selective estrogen receptor-α (ERα) ligand to modulate the inflammatory response but not cell proliferation. A crystal structure of the ERα ligand-binding domain (LBD) as a complex with resveratrol revealed a unique perturbation of the coactivator-binding surface, consistent with an altered coregulator recruitment profile. Gene expression analyses revealed significant overlap of TNFα genes modulated by resveratrol and estradiol. Furthermore, the ability of resveratrol to suppress interleukin-6 transcription was shown to require ERα and several ERα coregulators, suggesting that ERα functions as a primary conduit for resveratrol activity. DOI: http://dx.doi.org/10.7554/eLife.02057.001 PMID:24771768

  19. Modulating the bone marrow microenvironment:the role of DLL4:Notch signaling and hypoxia

    OpenAIRE

    Remédio, Leonor

    2013-01-01

    Tese de doutoramento, Biologia (Biologia Celular), Universidade de Lisboa, Faculdade de Ciências, 2013 Both cell-intrinsic and environmental cues drive hematopoiesis, which in adult mammals occurs mainly in the bone marrow (BM). BM endothelial cells that line the blood vessels contribute towards the regulation of hematopoiesis. In this Thesis, we used two strategies previously shown to increase vessel numbers, to assess the modulation of the BM “vascular niche” and its effects in hematopoi...

  20. IMMUNE RBF NETWORK AND ITS APPLICATION IN THE MODULATION-STYLE RECOGNITION OF RADAR SIGNALS

    Institute of Scientific and Technical Information of China (English)

    Gong Xinbao; Zang Xiaogang; Zhou Xilang; Hu Guangrui

    2003-01-01

    Based on Immune Programming(IP), a novel Radial Basis Function (RBF) networkdesigning method is proposed. Through extracting the preliminary knowledge about the widthof the basis function as the vaccine to form the immune operator, the algorithm reduces thesearching space of canonical algorithm and improves the convergence speed. The application ofthe RBF network trained with the algorithm in the modulation-style recognition of radar signalsdemonstrates that the network has a fast convergence speed with good performances.

  1. Modulation of FAK and Src adhesion signaling occurs independently of adhesion complex composition

    DEFF Research Database (Denmark)

    Horton, Edward R.; Humphries, Jonathan D.; Stutchbury, Ben

    2016-01-01

    of the key IAC signaling components focal adhesion kinase (FAK) and Src. FAK inhibition using AZ13256675 blocked FAKY397 phosphorylation but did not alter IAC composition, as reported by mass spectrometry. IAC composition was also insensitive to Src inhibition using AZD0530 alone or in combination with FAK...... inhibition. In contrast, kinase inhibition substantially reduced phosphorylation within IACs, cell migration and proliferation. Furthermore using fluorescence recovery after photobleaching, we found that FAK inhibition increased the exchange rate of a phosphotyrosine (pY) reporter (dSH2) at IACs. These data...... demonstrate that kinase-dependent signal propagation through IACs is independent of gross changes in IAC composition. Together, these findings demonstrate a general separation between the composition of IACs and their ability to relay pY-dependent signals....

  2. β-Spectrin regulates the hippo signaling pathway and modulates the basal actin network.

    Science.gov (United States)

    Wong, Kenneth Kin Lam; Li, Wenyang; An, Yanru; Duan, Yangyang; Li, Zhuoheng; Kang, Yibin; Yan, Yan

    2015-03-01

    Emerging evidence suggests functional regulation of the Hippo pathway by the actin cytoskeleton, although the detailed molecular mechanism remains incomplete. In a genetic screen, we identified a requirement for β-Spectrin in the posterior follicle cells for the oocyte repolarization process during Drosophila mid-oogenesis. β-spectrin mutations lead to loss of Hippo signaling activity in the follicle cells. A similar reduction of Hippo signaling activity was observed after β-Spectrin knockdown in mammalian cells. We further demonstrated that β-spectrin mutations disrupt the basal actin network in follicle cells. The abnormal stress fiber-like actin structure on the basal side of follicle cells provides a likely link between the β-spectrin mutations and the loss of the Hippo signaling activity phenotype.

  3. Stochastic resonance for signal-modulated pump noise in a single-mode laser

    Institute of Scientific and Technical Information of China (English)

    Liangying Zhang; Li Cao; Fahui Zhu

    2006-01-01

    By adopting the gain-noise model of the single-mode laser in which with bias and periodical signals serve as inputs, combining with the effect of coloured pump noise, we use the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity under the condition of pump noise and quantum noise cross-related in the form of δ function. It is found that with the change of pump noise correlation time, both SNR and the output power will occur stochastic resonance (SR). If the bias signal α is very small, changing the intensities of pump noise and quantum noise respectively does not lead to the appearance of SR in the SNR; while α increases to a certain number, SR appears.

  4. Extracellular modulation of Fibroblast Growth Factor signaling through heparan sulfate proteoglycans in mammalian development.

    Science.gov (United States)

    Matsuo, Isao; Kimura-Yoshida, Chiharu

    2013-08-01

    Fibroblast Growth Factor (FGF) signaling plays crucial roles in multiple cellular processes including cell proliferation, differentiation, survival, and migration during mammalian embryogenesis. In the extracellular matrix, as well as at the cell surface, the movement of FGF ligands to target cells and the subsequent complex formations with their receptors are positively and negatively controlled extracellularly by heparan sulfate proteoglycans (HSPGs) such as syndecans, glypicans, and perlecan. Additionally, spreading of HSPGs by cleavage with sheddases such as proteinases and heparanases, and the overall length and sulfation level of specific heparan sulfate structures further generate a great diversity of FGF signaling outcomes. This review presents our current understanding of the regulatory mechanisms of FGF signaling in extracellular spaces through HSPGs in mammalian development.

  5. Nuclear import of glucokinase in pancreatic beta-cells is mediated by a nuclear localization signal and modulated by SUMOylation.

    Science.gov (United States)

    Johansson, Bente Berg; Fjeld, Karianne; Solheim, Marie Holm; Shirakawa, Jun; Zhang, Enming; Keindl, Magdalena; Hu, Jiang; Lindqvist, Andreas; Døskeland, Anne; Mellgren, Gunnar; Flatmark, Torgeir; Njølstad, Pål Rasmus; Kulkarni, Rohit N; Wierup, Nils; Aukrust, Ingvild; Bjørkhaug, Lise

    2017-10-15

    The localization of glucokinase in pancreatic beta-cell nuclei is a controversial issue. Although previous reports suggest such a localization, the mechanism for its import has so far not been identified. Using immunofluorescence, subcellular fractionation and mass spectrometry, we present evidence in support of glucokinase localization in beta-cell nuclei of human and mouse pancreatic sections, as well as in human and mouse isolated islets, and murine MIN6 cells. We have identified a conserved, seven-residue nuclear localization signal ((30)LKKVMRR(36)) in the human enzyme. Substituting the residues KK(31,32) and RR(35,36) with AA led to a loss of its nuclear localization in transfected cells. Furthermore, our data indicates that SUMOylation of glucokinase modulates its nuclear import, while high glucose concentrations do not significantly alter the enzyme nuclear/cytosolic ratio. Thus, for the first time, we provide data in support of a nuclear import of glucokinase mediated by a redundant mechanism, involving a nuclear localization signal, and which is modulated by its SUMOylation. These findings add new knowledge to the functional role of glucokinase in the pancreatic beta-cell. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Calculus of the Power Spectral Density of Ultra Wide Band Pulse Position Modulation Signals Coded with Totally Flipped Code

    Directory of Open Access Journals (Sweden)

    DURNEA, T. N.

    2009-02-01

    Full Text Available UWB-PPM systems were noted to have a power spectral density (p.s.d. consisting of a continuous portion and a line spectrum, which is composed of energy components placed at discrete frequencies. These components are the major source of interference to narrowband systems operating in the same frequency interval and deny harmless coexistence of UWB-PPM and narrowband systems. A new code denoted as Totally Flipped Code (TFC is applied to them in order to eliminate these discrete spectral components. The coded signal transports the information inside pulse position and will have the amplitude coded to generate a continuous p.s.d. We have designed the code and calculated the power spectral density of the coded signals. The power spectrum has no discrete components and its envelope is largely flat inside the bandwidth with a maximum at its center and a null at D.C. These characteristics make this code suited for implementation in the UWB systems based on PPM-type modulation as it assures a continuous spectrum and keeps PPM modulation performances.

  7. A Hardware-Efficient Scalable Spike Sorting Neural Signal Processor Module for Implantable High-Channel-Count Brain Machine Interfaces.

    Science.gov (United States)

    Yang, Yuning; Boling, Sam; Mason, Andrew J

    2017-08-01

    Next-generation brain machine interfaces demand a high-channel-count neural recording system to wirelessly monitor activities of thousands of neurons. A hardware efficient neural signal processor (NSP) is greatly desirable to ease the data bandwidth bottleneck for a fully implantable wireless neural recording system. This paper demonstrates a complete multichannel spike sorting NSP module that incorporates all of the necessary spike detector, feature extractor, and spike classifier blocks. To meet high-channel-count and implantability demands, each block was designed to be highly hardware efficient and scalable while sharing resources efficiently among multiple channels. To process multiple channels in parallel, scalability analysis was performed, and the utilization of each block was optimized according to its input data statistics and the power, area and/or speed of each block. Based on this analysis, a prototype 32-channel spike sorting NSP scalable module was designed and tested on an FPGA using synthesized datasets over a wide range of signal to noise ratios. The design was mapped to 130 nm CMOS to achieve 0.75 μW power and 0.023 mm(2) area consumptions per channel based on post synthesis simulation results, which permits scalability of digital processing to 690 channels on a 4×4 mm(2) electrode array.

  8. Modulating sphingosine 1-phosphate signaling with DOP or FTY720 alleviates vascular and immune defects in mouse sepsis.

    Science.gov (United States)

    Hemdan, Nasr Y A; Weigel, Cynthia; Reimann, Christina-Maria; Gräler, Markus H

    2016-12-01

    Sepsis is a systemic inflammatory response to pathogens and a leading cause of hospital related mortality worldwide. Sphingosine 1-phosphate (S1P) regulates multiple cellular processes potentially involved in the pathogenesis of sepsis, including antigen presentation, lymphocyte egress, and maintenance of vascular integrity. We thus explored the impact of manipulating S1P signaling in experimental polymicrobial sepsis in mice. Administration of 4-deoxypyridoxine (DOP), an inhibitor of the S1P-degrading enzyme S1P-lyase, or of the sphingosine analog FTY720 that serves as an S1P receptor agonist after phosphorylation ameliorated morbidity, improved recovery from sepsis in surviving mice, and reduced sepsis-elicited hypothermia and body weight loss. Treated mice developed lymphopenia, leading to an accumulation of lymphocytes in peripheral lymph nodes, and reduced bacterial burden in liver, but not in blood. Sepsis-induced upregulation of mRNA expression of cytokines in spleen remained unchanged, but reduction of IL-6, TNF-α, MCP-1, and IL-10 in plasma was evident. DOP and FTY720 treatment significantly reduced levels of Evans blue leakage from blood into liver and lung, decreased hematocrit values, and lowered plasma levels of VEGF-A in septic mice. Collectively, our results indicate that modulation of S1P signaling showed a protective phenotype in experimental sepsis by modulating vascular and immune functions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The effect of carbon monoxide integrating nitric oxide through auxin signal in Arabidopsis to modulate iron deficiency

    Directory of Open Access Journals (Sweden)

    Liming eYang

    2016-03-01

    Full Text Available Carbon monoxide (CO and nitric oxide (NO are essential modulators that regulate the plant response to iron deficiency (-Fe. Auxin is a phytohormone that plays important roles in plant growth and development. We report here that in Arabidopsis –Fe enhanced heme oxygenase-dependent CO generation and auxin transport through redistribution of PIN1 protein, which subsequently increased NO accumulation; NO signaling regulated the activity of ferric chelate reductase (FCR and the expression of Fe-uptake genes including basic helix-loop-helix transcription factor (FIT and the ferric reduction oxidase 2 (FRO2. Over-expression of HY1 encoding heme oxygenase, or treatment with CO donor enhanced basipetal auxin transport, FCR activity, and the expressions of FIT and FRO2 under –Fe. Such effects were compromised in the mutant aux1-7 impaired in auxin transport or in the mutant noa1 or nia1/nia2 defective in NO biosynthesis. -Fe failed to promote auxin transport and FCR activity in hy1 mutant; such inability was reversed in the double mutant of hy1/yucca1 with elevated auxin production, or in hy1/cue1 mutant with NO over-accumulation. Taken together, our results suggest that CO modulates NO signaling through auxin to cope with Fe deficiency in Arabidopsis.

  10. The DET1-COP1-HY5 Pathway Constitutes a Multipurpose Signaling Module Regulating Plant Photomorphogenesis and Thermomorphogenesis

    Directory of Open Access Journals (Sweden)

    Carolin Delker

    2014-12-01

    Full Text Available Developmental plasticity enables plants to respond to elevated ambient temperatures by adapting their shoot architecture. On the cellular level, the basic-helix-loop-helix (bHLH transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4 coordinates this response by activating hormonal modules that in turn regulate growth. In addition to an unknown temperature-sensing mechanism, it is currently not understood how temperature regulates PIF4 activity. Using a forward genetic approach in Arabidopsis thaliana, we present extensive genetic evidence demonstrating that the DE-ETIOLATED 1 (DET1-CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1-ELONGATED HYPOCOTYL 5 (HY5-dependent photomorphogenesis pathway transcriptionally regulates PIF4 to coordinate seedling growth in response to elevated temperature. Our findings demonstrate that two of the most prevalent environmental cues, light and temperature, share a much larger set of signaling components than previously assumed. Similar to the toolbox concept in animal embryonic patterning, multipurpose signaling modules might have evolved in plants to translate various environmental stimuli into adaptational growth processes.

  11. High-resolution focal plane array IR detection modules and digital signal processing technologies at AIM

    Science.gov (United States)

    Cabanski, Wolfgang A.; Breiter, Rainer; Koch, R.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann; Eberhardt, Kurt; Oelmaier, Reinhard; Schneider, Harald; Walther, Martin

    2000-07-01

    Full video format focal plane array (FPA) modules with up to 640 X 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or platinum silicide (PtSi) and quantum well infrared photodetector (QWIP) technology as low cost alternatives to MCT for high performance IR imaging in the MWIR or long wave spectral band (LWIR). For the QWIP's, a new photovoltaic technology was introduced for improved NETD performance and higher dynamic range. MCT units provide fast frame rates > 100 Hz together with state of the art thermal resolution NETD rates of 30 - 60 Hz and provide thermal resolutions of NETD exchangeability of the units. New modular image processing hardware platforms and software for image visualization and nonuniformity correction including scene based self learning algorithms had to be developed to accomplish for the high data rates of up to 18 M pixels/s with 14-bit deep data, allowing to take into account nonlinear effects to access the full NETD by accurate reduction of residual fixed pattern noise. The main features of these modules are summarized together with measured performance data for long range detection systems with moderately fast to slow F-numbers like F/2.0 - F/3.5. An outlook shows most recent activities at AIM, heading for multicolor and faster frame rate detector modules based on MCT devices.

  12. Schisantherin A suppresses osteoclast formation and wear particle-induced osteolysis via modulating RANKL signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi; Zhang, Qing; Shen, Yi; Chen, Xia; Zhou, Feng; Peng, Dan, E-mail: xyeypd@163.com

    2014-07-04

    Highlights: • Schisantherin A suppresses osteoclasts formation and function in vitro. • Schisantherin A impairs RANKL signaling pathway. • Schisantherin A suppresses osteolysis in vivo. • Schisantherin A may be used for treating osteoclast related diseases. - Abstract: Receptor activator of NF-κB ligand (RANKL) plays critical role in osteoclastogenesis. Targeting RANKL signaling pathways has been a promising strategy for treating osteoclast related bone diseases such as osteoporosis and aseptic prosthetic loosening. Schisantherin A (SA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, has been used as an antitussive, tonic, and sedative agent, but its effect on osteoclasts has been hitherto unknown. In the present study, SA was found to inhibit RANKL-induced osteoclast formation and bone resorption. The osteoclastic specific marker genes induced by RANKL including c-Src, SA inhibited OSCAR, cathepsin K and TRAP in a dose dependent manner. Further signal transduction studies revealed that SA down-regulate RANKL-induced nuclear factor-kappaB (NF-κB) signaling activation by suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the NF-κB transcriptional activity. Moreover, SA also decreased the RANKL-induced MAPKs signaling pathway, including JNK and ERK1/2 posphorylation while had no obvious effects on p38 activation. Finally, SA suppressed the NF-κB and MAPKs subsequent gene expression of NFATc1 and c-Fos. In vivo studies, SA inhibited osteoclast function and exhibited bone protection effect in wear-particle-induced bone erosion model. Taken together, SA could attenuate osteoclast formation and wear particle-induced osteolysis by mediating RANKL signaling pathways. These data indicated that SA is a promising therapeutic natural compound for the treatment of osteoclast-related prosthesis loosening.

  13. Notch signaling modulates proliferative vitreoretinopathy via regulating retinal pigment epithelial-to-mesenchymal transition.

    Science.gov (United States)

    Zhang, Jingjing; Yuan, Gongqiang; Dong, Muchen; Zhang, Ting; Hua, Gao; Zhou, Qingjun; Shi, Weiyun

    2016-09-07

    Elevated Notch signaling has been verified in a large range of fibrotic diseases developed in the kidney, liver, and lung, inducing the development of the epithelial-mesenchymal transition (EMT). The aim of this study was to observe the involvement of Notch signaling in the EMT of retinal pigment epithelial (RPE) cells and the pathogenesis of proliferative vitreoretinopathy (PVR). In vitro cultivated human RPE cells (ARPE-19) were treated with 10 ng/mL transforming growth factor (TGF)-β1 for 24, 48, and 72 h. The expression levels of ZO-1, α-SMA, vimentin, Notch1 intracellular domain (NICD1), and Hes-1 were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence staining or Western blot. TGF-β1 induced EMT and the activation of Notch signaling in ARPE-19 cells. To examine the effect of Notch inhibition on TGF-β1-induced EMT and PVR formation, ARPE-19 cells were preincubated with γ-secretase inhibitor LY411575 before TGF-β1 treatment. Mouse PVR model was used for in vivo study. ARPE-19 cells were injected intravitreously with or without the LY411575 to examine the effect of Notch inhibition on PVR formation. LY411575 significantly attenuated EMT by inhibiting the Notch signaling activation in vitro. PVR was induced by intravitreal injections of ARPE-19 cells, while LY411575 inhibited mouse PVR formation in vivo. Notch signaling plays a critical role in TGF-β1-induced EMT in vitro and mice PVR model, which provides a novel insight into the pathogenesis of PVR. The specific inhibition of Notch signaling by γ-secretase inhibitor may provide a new approach for the prevention of PVR.

  14. Predicting speech intelligibility based on the signal-to-noise envelope power ratio after modulation-frequency selective processing.

    Science.gov (United States)

    Jørgensen, Søren; Dau, Torsten

    2011-09-01

    A model for predicting the intelligibility of processed noisy speech is proposed. The speech-based envelope power spectrum model has a similar structure as the model of Ewert and Dau [(2000). J. Acoust. Soc. Am. 108, 1181-1196], developed to account for modulation detection and masking data. The model estimates the speech-to-noise envelope power ratio, SNR(env), at the output of a modulation filterbank and relates this metric to speech intelligibility using the concept of an ideal observer. Predictions were compared to data on the intelligibility of speech presented in stationary speech-shaped noise. The model was further tested in conditions with noisy speech subjected to reverberation and spectral subtraction. Good agreement between predictions and data was found in all cases. For spectral subtraction, an analysis of the model's internal representation of the stimuli revealed that the predicted decrease of intelligibility was caused by the estimated noise envelope power exceeding that of the speech. The classical concept of the speech transmission index fails in this condition. The results strongly suggest that the signal-to-noise ratio at the output of a modulation frequency selective process provides a key measure of speech intelligibility.

  15. Nitric oxide-induced murine hematopoietic stem cell fate involves multiple signaling proteins, gene expression, and redox modulation.

    Science.gov (United States)

    Nogueira-Pedro, Amanda; Dias, Carolina C; Regina, Helena; Segreto, C; Addios, Priscilla C; Lungato, Lisandro; D'Almeida, Vania; Barros, Carlos C; Higa, Elisa M S; Buri, Marcus V; Ferreira, Alice T; Paredes-Gamero, Edgar Julian

    2014-11-01

    There are a growing number of reports showing the influence of redox modulation in cellular signaling. Although the regulation of hematopoiesis by reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been described, their direct participation in the differentiation of hematopoietic stem cells (HSCs) remains unclear. In this work, the direct role of nitric oxide (NO(•)), a RNS, in the modulation of hematopoiesis was investigated using two sources of NO(•) , one produced by endothelial cells stimulated with carbachol in vitro and another using the NO(•)-donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) in vivo. Two main NO(•) effects were observed: proliferation of HSCs-especially of the short-term HSCs-and its commitment and terminal differentiation to the myeloid lineage. NO(•)-induced proliferation was characterized by the increase in the number of cycling HSCs and hematopoietic progenitor cells positive to BrdU and Ki-67, upregulation of Notch-1, Cx43, PECAM-1, CaR, ERK1/2, Akt, p38, PKC, and c-Myc. NO(•)-induced HSCs differentiation was characterized by the increase in granulocytic-macrophage progenitors, granulocyte-macrophage colony forming units, mature myeloid cells, upregulation of PU.1, and C/EBPα genes concomitantly to the downregulation of GATA-3 and Ikz-3 genes, activation of Stat5 and downregulation of the other analyzed proteins mentioned above. Also, redox status modulation differed between proliferation and differentiation responses, which is likely associated with the transition of the proliferative to differentiation status. Our findings provide evidence of the role of NO(•) in inducing HSCs proliferation and myeloid differentiation involving multiple signaling. © 2014 AlphaMed Press.

  16. Significant Performance Advantage of Electroabsorption Modulator Integrated Distributed Feedback Laser (EML) Transmitter in Transporting Multicarrier QAM Signals

    NARCIS (Netherlands)

    Chand, Naresh; Bakker, Laurens; Veen, van Dora; Yadvish, Robert D.

    2001-01-01

    Data are presented that show that, for transporting quadrature amplitude modulated (QAM) radiofrequency (RF) subcarriers in suboctave frequency range, electroabsorption modulator integrated distributed feedback lasers (EMLs) can he modulated with significantly higher (2.5 times) modulation index wit

  17. Cyclic GMP signaling in cardiomyocytes modulates fatty acid trafficking and prevents triglyceride accumulation

    Science.gov (United States)

    While the balance between carbohydrates and fatty acids for energy production appears to be crucial for cardiac homeostasis, much remains to be learned about the molecular mechanisms underlying this relationship. Given the reported benefits of cGMP signaling on the myocardium, we investigated the im...

  18. Stromal IFN-γR-signaling modulates goblet cell function during Salmonella Typhimurium infection.

    Directory of Open Access Journals (Sweden)

    Pascal Songhet

    Full Text Available Enteropathogenic bacteria are a frequent cause of diarrhea worldwide. The mucosal defenses against infection are not completely understood. We have used the streptomycin mouse model for Salmonella Typhimurium diarrhea to analyze the role of interferon gamma receptor (IFN-γR-signaling in mucosal defense. IFN-γ is known to contribute to acute S. Typhimurium diarrhea. We have compared the acute mucosal inflammation in IFN-γR(-/- mice and wild type animals. IFN-γR(-/- mice harbored increased pathogen loads in the mucosal epithelium and the lamina propria. Surprisingly, the epithelium of the IFN-γR(-/- mice did not show the dramatic "loss" of mucus-filled goblet cell vacuoles, a hallmark of the wild type mucosal infection. Using bone marrow chimeric mice we established that IFN-γR-signaling in stromal cells (e.g. goblet cells, enterocytes controlled mucus excretion/vacuole loss by goblet cells. In contrast, IFN-γR-signaling in bone marrow-derived cells (e.g. macrophages, DCs, PMNs was required for restricting pathogen growth in the gut tissue. Thus IFN-γR-signaling influences different mucosal responses to infection, including not only pathogen restriction in the lamina propria, but, as shown here, also goblet cell function.

  19. Numb/Notch signaling pathway modulation enhances human pancreatic cancer cell radiosensitivity.

    Science.gov (United States)

    Bi, Yi-Liang; Min, Min; Shen, Wei; Liu, Yan

    2016-11-01

    The present study aims to evaluate whether repression of the Numb/Notch signaling pathway affects the radiosensitivity of human pancreatic cancer cell lines. Different doses of X-rays (0, 2, 3, 4, and 5 Gy) were applied to the PANC-1, SW1990, and MIA PaCa-2 human pancreatic cancer cell lines, and the Numb/Notch pathway inhibitor DAPT was added at different doses (0, 1, 3, and 5 μmol/l). MTT assay, colony formation assay, flow cytometry, scratch assay, and Transwell experiments were performed, and qRT-PCR and Western blot were conducted for the detection of Numb expression. Tumorigenicity assay in nude mice was carried out to verify the influence of blocker of the Numb/Notch signaling pathway on the radiosensitivity of xenograft tumors. The MTT assay, colony formation assay and flow cytometry experiments revealed that proliferation decreased as radiation dose increased. The viability of PANC-1 cells at 5 Gy, SW 1990 cells at 4 Gy and 5 Gy, and MIA PaCa-2 cells at 2-5 Gy was significantly lower than that of non-irradiated cells (all P cancer cells is associated with X-ray radiation and that inhibition of the Numb/Notch signaling pathway can enhance radiosensitivity, suggesting that inhibition of the Numb/Notch signaling pathway may serve as a potential target for clinical improvement of the radiosensitivity of pancreatic cancer.

  20. Low modulation index RF signal detection for a passive UHF RFID transponder

    Institute of Scientific and Technical Information of China (English)

    Liu Zhongqi; Zhang Chun; Li Yongming; Wang Zhihua

    2009-01-01

    ower into voltage signal, the detection sensitivity is ensured over a wide power range with low power consumption of 8.6μW. The chip is implemented in UMC 0.18μm mix-mode CMOS technology, and the chip area is 0.06 mm2.