Science.gov

Sample records for generator modules m-7

  1. The calcium sensor GhCaM7 promotes cotton fiber elongation by modulating reactive oxygen species (ROS) production.

    PubMed

    Tang, Wenxin; Tu, Lili; Yang, Xiyan; Tan, Jiafu; Deng, Fenglin; Hao, Juan; Guo, Kai; Lindsey, Keith; Zhang, Xianlong

    2014-04-01

    Fiber elongation is the key determinant of fiber quality and output in cotton (Gossypium hirsutum). Although expression profiling and functional genomics provide some data, the mechanism of fiber development is still not well understood. Here, a gene encoding a calcium sensor, GhCaM7, was isolated based on its high expression level relative to other GhCaMs in fiber cells at the fast elongation stage. The level of expression of GhCaM7 in the wild-type and the fuzzless/lintless mutant correspond to the presence and absence, respectively, of fiber initials. Overexpressing GhCaM7 promotes early fiber elongation, whereas GhCaM7 suppression by RNAi delays fiber initiation and inhibits fiber elongation. Reactive oxygen species (ROS) play important roles in early fiber development. ROS induced by exogenous hydrogen peroxide (H2 O2 ) and Ca(2+) starvation promotes early fiber elongation. GhCaM7 overexpression fiber cells show increased ROS concentrations compared with the wild-type, while GhCaM7 RNAi fiber cells have reduced concentrations. Furthermore, we show that H2 O2 enhances Ca(2+) influx into the fiber and feedback-regulates the expression of GhCaM7. We conclude that GhCaM7, Ca(2+) and ROS are three important regulators involved in early fiber elongation. GhCaM7 might modulate ROS production and act as a molecular link between Ca(2+) and ROS signal pathways in early fiber development.

  2. Second generation SLAC modulator

    SciTech Connect

    Donaldson, A.R.; Cron, J.C.; Hanselman, R.R.

    1986-06-01

    The Stanford Linear Accelerator Laboratory has undertaken the construction of a single pass electron-positron collider. In order to reach required beam energy 235 new klystrons needed upgraded modulator systems. The collider will use 50 GeV electrons and positrons. The increase in accelerator energy from the present 30 GeV necessitates the replacement of existing 35 MW klystrons with new 67 MW units. The doubling of klystron output power required a redesign of the modulator system. The 67 MW klystron needs a 350 kV beam voltage pulse with a 3.7 ..mu..s pulse width. A new pulse transformer was designed to deliver the increased voltage and pulse width. Pulse cable design was evaluated to obtain increased reliability of that critical element. The modulator, with the exception of its power supply, was rebuilt to produce the required power increase while enhancing reliability and improving maintainability. An investigation of present thyratron switch tube performance under the new operating conditions resulted in agitation and some warranted panic but these conditions were mitigated after several successful experiments and some evolutionary narrowing of the klystron pulse width. The discussion will cover the upgraded modulator system specifications and some details of the new pulse transformer tank, pulse cable, modulator, and modulator switch tube.

  3. Modulation compression for short wavelength harmonic generation

    SciTech Connect

    Qiang, J.

    2010-01-11

    Laser modulator is used to seed free electron lasers. In this paper, we propose a scheme to compress the initial laser modulation in the longitudinal phase space by using two opposite sign bunch compressors and two opposite sign energy chirpers. This scheme could potentially reduce the initial modulation wavelength by a factor of C and increase the energy modulation amplitude by a factor of C, where C is the compression factor of the first bunch compressor. Such a compressed energy modulation can be directly used to generate short wavelength current modulation with a large bunching factor.

  4. ULF Generation by Modulated Ionospheric Heating

    NASA Astrophysics Data System (ADS)

    Chang, C.; Labenski, J.; Wallace, T.; Papadopoulos, K.

    2013-12-01

    Modulated ionospheric heating experiments designed to generate ULF waves using the HAARP heater have been conducted since 2007. Artificial ULF waves in the Pc1 frequency range were observed from space and by ground induction magnetometers located in the vicinity of the heater as well as at long distances. Two distinct generation mechanisms of artificial ULF waves were identified. The first was electroject modulation under geomagnetically disturbed conditions. The second was pressure modulation in the E and F regions of the ionosphere under quiet conditions. Ground detections of ULF waves near the heater included both Shear Alfven waves and Magnetosonic waves generated by electrojet and/or pressure modulations. Distant ULF detections involved Magnetosonic wave propagation in the Alfvenic duct with pressure modulation as the most likely source. Summary of our observations and theoretical interpretations will be presented at the meeting. We would like to acknowledge the support provided by the staff at the HAARP facility during our ULF experiments.

  5. PSCAD Modules Representing PV Generator

    SciTech Connect

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2013-08-01

    Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults.

  6. Microglia modulate respiratory rhythm generation and autoresuscitation.

    PubMed

    Lorea-Hernández, Jonathan-Julio; Morales, Teresa; Rivera-Angulo, Ana-Julia; Alcantara-Gonzalez, David; Peña-Ortega, Fernando

    2016-04-01

    Inflammation has been linked to the induction of apneas and Sudden Infant Death Syndrome, whereas proinflammatory mediators inhibit breathing when applied peripherally or directly into the CNS. Considering that peripheral inflammation can activate microglia in the CNS and that this cell type can directly release all proinflammatory mediators that modulate breathing, it is likely that microglia can modulate breathing generation. It might do so also in hypoxia, since microglia are sensitive to hypoxia, and peripheral proinflammatory conditions affect gasping generation and autoresuscitation. Here, we tested whether microglial activation or inhibition affected respiratory rhythm generation. By measuring breathing as well as the activity of the respiratory rhythm generator (the preBötzinger complex), we found that several microglial activators or inhibitors, applied intracisternally in vivo or in the recording bath in vitro, affect the generation of the respiratory rhythms both in normoxia and hypoxia. Furthermore, microglial activation with lipopolysaccharide affected the ability of the animals to autoresuscitate after hypoxic conditions, an effect that is blocked when lipopolysaccharide is co-applied with the microglial inhibitor minocycline. Moreover, we found that the modulation of respiratory rhythm generation induced in vitro by microglial inhibitors was reproduced by microglial depletion. In conclusion, our data show that microglia can modulate respiratory rhythm generation and autoresuscitation.

  7. Power Generator with Thermo-Differential Modules

    NASA Technical Reports Server (NTRS)

    Saiz, John R.; Nguyen, James

    2010-01-01

    A thermoelectric power generator consists of an oven box and a solar cooker/solar reflector unit. The solar reflector concentrates sunlight into heat and transfers the heat into the oven box via a heat pipe. The oven box unit is surrounded by five thermoelectric modules and is located at the bottom end of the solar reflector. When the heat is pumped into one side of the thermoelectric module and ejected from the opposite side at ambient temperatures, an electrical current is produced. Typical temperature accumulation in the solar reflector is approximately 200 C (392 F). The heat pipe then transfers heat into the oven box with a loss of about 40 percent. At the ambient temperature of about 20 C (68 F), the temperature differential is about 100 C (180 F) apart. Each thermoelectric module, generates about 6 watts of power. One oven box with five thermoelectric modules produces about 30 watts. The system provides power for unattended instruments in remote areas, such as space colonies and space vehicles, and in polar and other remote regions on Earth.

  8. Developing instrumentation to characterize thermoelectric generator modules.

    PubMed

    Liu, Dawei; Li, Qiming; Peng, Wenbo; Zhu, Lianjun; Gao, Hu; Meng, Qingsen; Jin, A J

    2015-03-01

    Based on the law of physics, known as "Seebeck effect," a thermoelectric generator (TEG) produces electricity when the temperature differential is applied across the TEG. This article reports a precision method in characterizing TEG modules. A precision instrument is constructed to study thermoelectric conversion in terms of output power and efficiency of TEG modules. The maximum allowable TEG module size is 150 mm, and the preferred size is from 30 mm to 60 mm. During measurements, the highest hot side temperature is 500 °C and the cold side temperature can be adjusted from room temperature to 100 °C. A mechanical structure is developed to control the pressure and parallelism of the clamping force of the TEG on both its hot and cold sides. A heat flux measurement module is installed at its cold side, and the heat flux through TEGs can be measured in position. Finally, the energy conversion efficiency of TEGs is calculated from experimental data of both an output power and a heat flux. PMID:25832254

  9. Developing instrumentation to characterize thermoelectric generator modules

    NASA Astrophysics Data System (ADS)

    Liu, Dawei; Li, Qiming; Peng, Wenbo; Zhu, Lianjun; Gao, Hu; Meng, Qingsen; Jin, A. J.

    2015-03-01

    Based on the law of physics, known as "Seebeck effect," a thermoelectric generator (TEG) produces electricity when the temperature differential is applied across the TEG. This article reports a precision method in characterizing TEG modules. A precision instrument is constructed to study thermoelectric conversion in terms of output power and efficiency of TEG modules. The maximum allowable TEG module size is 150 mm, and the preferred size is from 30 mm to 60 mm. During measurements, the highest hot side temperature is 500 °C and the cold side temperature can be adjusted from room temperature to 100 °C. A mechanical structure is developed to control the pressure and parallelism of the clamping force of the TEG on both its hot and cold sides. A heat flux measurement module is installed at its cold side, and the heat flux through TEGs can be measured in position. Finally, the energy conversion efficiency of TEGs is calculated from experimental data of both an output power and a heat flux.

  10. Module for Oxygenating Water without Generating Bubbles

    NASA Technical Reports Server (NTRS)

    Gonzalez-Martin, Anuncia; Sidik, Reyimjan; Kim, Jinseong

    2004-01-01

    A module that dissolves oxygen in water at concentrations approaching saturation, without generating bubbles of oxygen gas, has been developed as a prototype of improved oxygenators for water-disinfection and water-purification systems that utilize photocatalyzed redox reactions. Depending on the specific nature of a water-treatment system, it is desirable to prevent the formation of bubbles for one or more reasons: (1) Bubbles can remove some organic contaminants from the liquid phase to the gas phase, thereby introducing a gas-treatment problem that complicates the overall water-treatment problem; and/or (2) in some systems (e.g., those that must function in microgravity or in any orientation in normal Earth gravity), bubbles can interfere with the flow of the liquid phase. The present oxygenation module (see Figure 1) is a modified version of a commercial module that contains >100 hollow polypropylene fibers with a nominal pore size of 0.05 m and a total surface area of 0.5 m2. The module was originally designed for oxygenation in a bioreactor, with no water flowing around or inside the tubes. The modification, made to enable the use of the module to oxygenate flowing water, consisted mainly in the encapsulation of the fibers in a tube of Tygon polyvinyl chloride (PVC) with an inside diameter of 1 in. (approx.=25 mm). In operation, water is pumped along the insides of the hollow fibers and oxygen gas is supplied to the space outside the hollow tubes inside the PVC tube. In tests, the pressure drops of water and oxygen in the module were found to be close to zero at water-flow rates ranging up to 320 mL/min and oxygen-flow rates up to 27 mL/min. Under all test conditions, no bubbles were observed at the water outlet. In some tests, flow rates were chosen to obtain dissolved-oxygen concentrations between 25 and 31 parts per million (ppm) . approaching the saturation level of approx.=35 ppm at a temperature of 20 C and pressure of 1 atm (approx.=0.1 MPa). As one

  11. Influence of large signal modulation on photonic UWB generation based on electro-optic modulator.

    PubMed

    Gu, Rong; Pan, Shilong; Chen, Xiangfei; Pan, Minghai; Ben, De

    2011-07-01

    Various schemes based on electro-optic modulators have been reported to generate ultra-wideband (UWB) signals in the optical domain, but the availability of these methods always relies on small signal modulation. In this paper, the influence of large signal modulation on two typical schemes, representing two major categories of external-modulator-based photonic UWB generation schemes, is analytically and numerically studied. While the quasi single-sideband UWB (QSSB-UWB) pulse can maintain its shape, the Gaussian UWB (GUWB) generation scheme suffers serious modulation distortion when the phase modulation index is greater than π/6. The modulation distortion would have negative impact on the receiver sensitivity when the signal is sent to a correlation receiver.

  12. Modulation improvements in the 201 MHZ RF generators at LAMPF

    SciTech Connect

    Parsons, W M; Lyles, J T.M.; Harris, H W

    1992-01-01

    Radio-frequency generators, operating at 201 MHz, power the first four stages of the Los Alamos Meson Physics Facility (LAMPF) accelerator. Each generator consists of four stages of seriesconnected, vacuum-tube amplifiers. The modulation scheme for each stage is different. The fist amplifier is a grid-modulated tetrode that produces 500 W peak-power. The second amplifier is a drive-modulated tetrode that produces 5 kill peak-power. The third stage is a grid- and plate-modulated tetrode that produces 130 kill peak-power. The last stage is a plate-modulated triode that produces 2.5 MW peak power. A modernization program has been initiated to improve the reliability of each of these stages. The first two stages of each generator are being replaced with a single, drive-modulated, solid-state amplifier. Specifications for the amplifier design, and requirements for integration into the system are presented. The third stage will be converted to a drive-modulated system using the current tetrode. This modification involves the development of a 17-kV, 15-A switching supply to replace the present plate-modulator. Design requirements for this switching supply are presented. The final stage will remain plate-modulated but will contain a new driver unit for the modulator tube.

  13. Thermionic generator module with heat pipes

    SciTech Connect

    Horner-Richardson, K.; Ernst, D.M.

    1993-06-15

    A thermionic converter module is described comprising: a first heat pipe with an annular casing which has a first surface located on an inside surface of the annular casing, at least part of the first surface of the casing of the first heat pipe having constructed upon it a thermionic converter emitter located so that heat will be transferred by conduction from the first heat pipe casing to the thermionic converter emitter; a second heat pipe with a casing which has a second surface, the second surface being located within the first surface of the annular casing of the first heat pipe so that it is surrounded by the first surface; a thermionic converter collector located so as to transfer heat by conduction to the second surface of the casing of the second heat pipe with the thermionic converter collector being adjacent to the thermionic converter emitter but being separated from the thermionic converter emitter by an inter electrode space; and end fitting structures located so that, with the thermionic converter collector and the thermionic converter emitter, they complete an enclosure around the inter electrode space and form an evacuated enclosure within which are located the thermionic converter collector and the thermionic converter emitter.

  14. Next generation photoactivated spatial light modulators

    NASA Astrophysics Data System (ADS)

    Marlor, Guy A.; Zhang, Robin Y.; McMurray, Robert E., Jr.

    1995-04-01

    The ability to translate digital images into photo-recordable images is one characteristic of a light valve. It is now becoming evident that resolutions will be achieved in this process which will match the resolution capabilities of the normal eye. Thus the spatial light modulator can play a key role as a transducer between digital memories and the user who wishes this information to be presented in a graphical, real world format. The advantages of a light valve which does not have a particular pixel structure, i.e. photoactivated light valve, are many. Newer input scanning techniques are moving to the point where small compact structures are becoming feasible. The challenges between a raster scanned structure and an x-y matrix scanned structure represent two extremes. The raster scan addressing requires an increasingly high bandwidth video amplifier. The x-y matrix address requires an outstanding number of perfect address lines and drive transistors. It is likely that a linear array of LED's scanned in one dimension, will be the preferred configuration for very high quality output. Photoconductors, especially composite phototransistor configurations, allow the expansion of the response of a given device well into the best output wavelengths of LED's. This class of device, parallel drive in one dimension and scanned in the orthogonal dimension begins to display the real capability of the optical computing nature of these light valves.

  15. Subpicosecond-pulse generation through cross-phase-modulation-induced modulational instability in optical fibers.

    PubMed

    Gouveia-Neto, A S; Faldon, M E; Sombra, A S; Wigley, P G; Taylor, J R

    1988-10-01

    We report subpicosecond-pulse generation at 1.319 microm in a single-mode optical fiber by modulational instability induced through cross-phase modulation by 1.06-microm pulses propagating in the normal dispersion regime. Pulse-repetition rates approaching 300 GHz were achieved.

  16. Design of the Second-Generation ILC Marx Modulator

    SciTech Connect

    Kemp, M.A.; Benwell, A.; Burkhart, C.; Larsen, R.; MacNair, D.; Nguyen, M.; Olsen, J.; /SLAC

    2010-09-14

    SLAC National Accelerator Laboratory (SLAC) has initiated a program to design and build a Marx-topology modulator to produce a relatively compact, low-cost, high availability klystron modulator for the International Linear Collider (ILC). Building upon the success of the P1 Marx, the SLAC P2 Marx is a second-generation modulator whose design further emphasizes the qualities of modularity and high-availability. This paper outlines highlights of this design and presents single-cell performance data obtained during the proof-of-concept phase of the project.

  17. Generation of pure electrical quadrature amplitude modulation with photonic vector modulator.

    PubMed

    Corral, Juan L; Sambaraju, Rakesh; Piqueras, Miguel A; Polo, Valentín

    2008-06-15

    A photonic vector modulator architecture for generating pure quadrature amplitude modulation (QAM) signals is presented. An electrical quadrature-modulated signal at microwave-millimeter-wave frequencies is generated from its corresponding baseband in-phase (I) and quadrature (Q) components. In the proposed scheme, no electrical devices apart from the electrical tone oscillator are needed in the generation process. In addition, the purity of the generated signal is increased, and the hardware requirements are reduced when compared with previously proposed architectures so a highly compact low-cost architecture can be implemented. A pure 1.25 Gbit/s 4-QAM signal has been experimentally generated at a 42 GHz carrier frequency.

  18. Electrical power generation by mechanically modulating electrical double layers.

    PubMed

    Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

    2013-01-01

    Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future. PMID:23403587

  19. Electrical power generation by mechanically modulating electrical double layers.

    PubMed

    Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

    2013-01-01

    Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future.

  20. Individual Module Maximum Power Point Tracking for Thermoelectric Generator Systems

    NASA Astrophysics Data System (ADS)

    Vadstrup, Casper; Schaltz, Erik; Chen, Min

    2013-07-01

    In a thermoelectric generator (TEG) system the DC/DC converter is under the control of a maximum power point tracker which ensures that the TEG system outputs the maximum possible power to the load. However, if the conditions, e.g., temperature, health, etc., of the TEG modules are different, each TEG module will not produce its maximum power. If each TEG module is controlled individually, each TEG module can be operated at its maximum power point and the TEG system output power will therefore be higher. In this work a power converter based on noninverting buck-boost converters capable of handling four TEG modules is presented. It is shown that, when each module in the TEG system is operated under individual maximum power point tracking, the system output power for this specific application can be increased by up to 8.4% relative to the situation when the modules are connected in series and 16.7% relative to the situation when the modules are connected in parallel.

  1. Application of field-modulated generator systems to dispersed solar thermal electric generation

    NASA Technical Reports Server (NTRS)

    Ramakumar, R.

    1979-01-01

    The state-of-the-art of field modulated generation system (FMGS) is presented, and the application of FMGS to dispersed solar thermal electric generation is discussed. The control and monitoring requirements for solar generation system are defined. A comparison is presented between the FMGS approach and other options and the technological development needs are discussed.

  2. Electro-optic modulator capable of generating simultaneous amplitude and phase modulations.

    PubMed

    Cusack, Benedict J; Sheard, Benjamin S; Shaddock, Daniel A; Gray, Malcolm B; Lam, Ping Koy; Whitcomb, Stan E

    2004-09-10

    We report on the analysis and prototype characterization of a dual-electrode electro-optic modulator that can generate both amplitude and phase modulations with a selectable relative phase, termed a quadrature variable modulator (QVM). All modulation states can be reached by tuning only the electrical inputs, facilitating real-time tuning, and the device has shown good suppression and stability properties. A mathematical analysis is presented, including the development of a geometric-phase representation for modulation. The experimental characterization of the device shows that relative suppressions of 38, 39, and 30 dB for phase, single sideband, and carrier-suppressed modulations, respectively, can be obtained as well as that the device is well behaved when scanning continuously through the parameter space of modulations. The QVM is compared with existing optical configurations that can produce amplitude and phase-modulation combinations in the context of applications such as the tuning of lock points in optical-locking schemes, single-sideband applications, modulation fast-switching applications, and applications requiring combined modulations. PMID:15468710

  3. Power Generation Evaluated on a Bismuth Telluride Unicouple Module

    NASA Astrophysics Data System (ADS)

    Hu, Xiaokai; Nagase, Kazuo; Jood, Priyanka; Ohta, Michihiro; Yamamoto, Atsushi

    2015-06-01

    The power generated by a thermoelectric unicouple module made of Bi2Te3 alloy was evaluated by use of a newly developed instrument. An electrical load was connected to the module, and the terminal voltage and output power of the module were obtained by altering electric current. Water flow was used to cool the cold side of the module and for heat flow measurement, by monitoring inlet and outlet temperatures. When the electric current was increased, heat flow was enhanced as a result of the Peltier effect and Joule heating. Voltage, power, heat flow, and efficiency as functions of current were determined for hot-side temperatures from 50 to 220°C. Maximum power output and peak conversion efficiency could thus be easily derived for each temperature.

  4. Mechanism and modulation of terahertz generation from a semimetal - graphite

    NASA Astrophysics Data System (ADS)

    Ye, Tong; Meng, Sheng; Zhang, Jin; E, Yiwen; Yang, Yuping; Liu, Wuming; Yin, Yan; Wang, Li

    2016-03-01

    Semi-metals might offer a stronger interaction and a better confinement for terahertz wave than semiconductors, while preserve tunability. Particularly, graphene-based materials are envisioned as terahertz modulators, filters and ultra-broadband sources. However, the understanding of terahertz generation from those materials is still not clear, thus limits us recognizing the potential and improving device performances. Graphite, the mother material of graphene and a typical bulk semi-metal, is a good system to study semi-metals and graphene-based materials. Here we experimentally modulate and maximize the terahertz signal from graphite surface, thus reveal the mechanism - surface field driving photon induced carriers into transient current to radiate terahertz wave. We also discuss the differences between graphite and semiconductors; particularly graphite shows very weak temperature dependency from room temperature to 80 °C. Above knowledge will help us understand terahertz generations, achieve maximum output and electric modulation, in semi-metal or graphene based devices.

  5. Imaging Collagen Orientation Using Polarization-Modulated Second Harmonic Generation

    SciTech Connect

    Stoller, P; Celliers, P M; Reiser, K M; Rubenchik, A M

    2002-01-10

    We use polarization-modulated second harmonic generation to image fiber orientation in collagen tissues, with an axial resolution of about 10 {micro}m and a transverse resolution of up to 1 {micro}m. A linearly polarized ultra-short pulse (200 fs) Ti:Sapphire laser beam is modulated using an electro-optic modulator and quarter-wave plate combination and focused onto a translation stage mounted sample using a microscope objective. The generated second harmonic light is collected using a photomultiplier tube and demodulated using phase sensitive detection to obtain signal intensity and fiber orientation information. In order to obtain second harmonic generation images of different types of collagen organization, we analyze several different tissues, including rat-tail tendon, mouse aorta, mouse fibrotic liver, and porcine skin. We can use our technique to image fibrotic tissue in histological sections of damaged liver and to identify burned tissue in porcine skin to a depth of a few hundred microns. Polarization-modulated second harmonic generation potentially could be a useful clinical technique for diagnosing collagen related disease or damage, especially in the skin.

  6. Different Solutions for the Generator-accelerator Module

    NASA Astrophysics Data System (ADS)

    Savin, E. A.; Matsievskiy, S. V.; Sobenin, N. P.; Zavadtsev, A. A.; Zavadtsev, D. A.

    The most important part of the particle accelerators [1] - is the power generator together with the whole feeding system [2]. All types of generators, such as klystrons, magnetrons, solid state generators cover their own field of power and pulse length values. For the last couple of year the Inductive Output Tubes (IOT) becomes very popular because of their comparative construction simplicity: it represents the klystron output cavity with the grid modulated electron beam injected in it. Now such IOTs are used with the superconductive particle accelerators at 700 MHz operating frequency with around 1MW output power. Higher frequencies problem - is the inability to apply high frequency modulated voltage to the grid. Thus we need to figure out some kind of RF gun. But this article is about the first steps of the geometry and beam dynamics simulation in the six beam S-band IOT, which will be used with the compact biperiodic accelerating structure.

  7. Thermoelectric generator having a resiliently mounted removable thermoelectric module

    DOEpatents

    Purdy, David L.; Shapiro, Zalman M.; Hursen, Thomas F.; Maurer, Gerould W.

    1976-11-02

    An electrical generator having an Isotopic Heat Capsule including radioactive fuel rod 21 as a primary heat source and Thermoelectric Modules 41 and 43 as converters. The Biological Shield for the Capsule is suspended from Spiders at each end each consisting of pretensioned rods 237 and 239 defining planes at right angles to each other. The Modules are mounted in cups 171 of transition members 173 of a heat rejection Fin Assembly whose fins 195 and 197 extend from both sides of the transition member 173 for effective cooling.

  8. Modulation of photoacoustic signal generation from metallic surfaces.

    PubMed

    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. Generation of axially modulated plasma waveguides using a spatial light modulator.

    PubMed

    Hine, G A; Goers, A J; Feder, L; Elle, J A; Yoon, S J; Milchberg, H M

    2016-08-01

    We demonstrate the generation of axially modulated plasma waveguides using spatially patterned high-energy laser pulses. A spatial light modulator (SLM) imposes transverse phase front modulations on a low-energy (10 mJ) laser pulse which is interferometrically combined with a high-energy (130-450 mJ) pulse, sculpting its intensity profile. This enables dynamic and programmable shaping of the laser profile limited only by the resolution of the SLM and the intensity ratio of the two pulses. The plasma density profile formed by focusing the patterned pulse with an axicon lens is likewise dynamic and programmable. Centimeter-scale, axially modulated plasmas of varying shape and periodicity are demonstrated. PMID:27472585

  10. Electrical Power Generation by Mechanically Modulating Electrical Double Layers

    NASA Astrophysics Data System (ADS)

    Pak, Hyuk Kyu; Moon, Jong Kyun

    2014-11-01

    Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system and for understanding the interfacial charge distribution in solid-liquid interfaces in the near future. This work was supported by Center for Soft and Living Matter through IBS prgram in Korea.

  11. Somatostatin modulates generation of inspiratory rhythms and determines asphyxia survival.

    PubMed

    Ramírez-Jarquín, Josué O; Lara-Hernández, Sergio; López-Guerrero, Juan J; Aguileta, Miguel A; Rivera-Angulo, Ana J; Sampieri, Alicia; Vaca, Luis; Ordaz, Benito; Peña-Ortega, Fernando

    2012-04-01

    Breathing and the activity of its generator (the pre-Bötzinger complex; pre-BötC) are highly regulated functions. Among neuromodulators of breathing, somatostatin (SST) is unique: it is synthesized by a subset of glutamatergic pre-BötC neurons, but acts as an inhibitory neuromodulator. Moreover, SST regulates breathing both in normoxic and in hypoxic conditions. Although it has been implicated in the neuromodulation of breathing, neither the locus of SST modulation, nor the receptor subtypes involved have been identified. In this study, we aimed to fill in these blanks by characterizing the SST-induced regulation of inspiratory rhythm generation in vitro and in vivo. We found that both endogenous and exogenous SST depress all preBötC-generated rhythms. While SST abolishes sighs, it also decreases the frequency and increases the regularity of eupnea and gasping. Pharmacological experiments showed that SST modulates inspiratory rhythm generation by activating SST receptor type-2, whose mRNA is abundantly expressed in the pre-Bötzinger complex. In vivo, blockade of SST receptor type-2 reduces gasping amplitude and consequently, it precludes auto-resuscitation after asphyxia. Based on our findings, we suggest that SST functions as an inhibitory neuromodulator released by excitatory respiratory neurons when they become overactivated in order to stabilize breathing rhythmicity in normoxic and hypoxic conditions.

  12. Theoretical Approach to Predict the Performance of Thermoelectric Generator Modules

    NASA Astrophysics Data System (ADS)

    Elarusi, Abdulmunaem H.; Fagehi, Hassan; Lee, Hosung; Attar, Alaa

    2016-10-01

    The aim of this work was to examine the validity of the thermoelectric modules' performance predicted by formulating the effective thermoelectric material properties. The three maximum parameters (output power, current, and efficiency) are defined in terms of the average temperature of the thermoelectric generator (TEG). These three maximum parameters, which are either taken from commercial TEG modules or measurements for particular operating conditions, are used to define the effective material properties (Seebeck coefficient, thermal conductivity, and electrical resistivity). The commercial performance curves provided by the manufacturer were compared with the results obtained here by the effective material properties with the simple standard thermoelectric equations. It has been found that this technique predicts the performance of four commercial thermoelectric modules with fair to good accuracy. The characteristics of the TEGs were represented using the normalized charts constructed by formulating the parameters as a fraction of over the maximum parameters. The normalized charts would be universal for any given TEG module once the thermoelectric material is known.

  13. Mechanism and modulation of terahertz generation from a semimetal - graphite

    PubMed Central

    Ye, Tong; Meng, Sheng; Zhang, Jin; E, Yiwen; Yang, Yuping; Liu, Wuming; Yin, Yan; Wang, Li

    2016-01-01

    Semi-metals might offer a stronger interaction and a better confinement for terahertz wave than semiconductors, while preserve tunability. Particularly, graphene-based materials are envisioned as terahertz modulators, filters and ultra-broadband sources. However, the understanding of terahertz generation from those materials is still not clear, thus limits us recognizing the potential and improving device performances. Graphite, the mother material of graphene and a typical bulk semi-metal, is a good system to study semi-metals and graphene-based materials. Here we experimentally modulate and maximize the terahertz signal from graphite surface, thus reveal the mechanism - surface field driving photon induced carriers into transient current to radiate terahertz wave. We also discuss the differences between graphite and semiconductors; particularly graphite shows very weak temperature dependency from room temperature to 80 °C. Above knowledge will help us understand terahertz generations, achieve maximum output and electric modulation, in semi-metal or graphene based devices. PMID:26972818

  14. Generation of Coherent X-Ray Radiation through Modulation Compression

    SciTech Connect

    Qiang, Ji; Wu, Juhao; /SLAC

    2012-06-12

    In this paper, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulator, a laser chirper and two bunch compressors to generate a prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. The initial modulation energy wavelength can be compressed by a factor of 1 + h{sub b}R{sub 56}{sup a} in phase space, where h{sub b} is the energy bunch length chirp introduced by the laser chirper, R{sub 56}{sup a} is the momentum compaction factor of the first bunch compressor. As an illustration, we present an example to generate more than 400 MW, 170 attoseconds pulse, 1 nm coherent X-ray radiation using a 60 A electron beam out of the linac and 200 nm laser seed. Both the final wavelength and the radiation pulse length in the proposed scheme are tunable by adjusting the compression factor and the laser parameters.

  15. Photosensitizing nanoparticles and the modulation of ROS generation

    PubMed Central

    Tada, Dayane B.; Baptista, Mauricio S.

    2015-01-01

    The association of PhotoSensitizer (PS) molecules with nanoparticles (NPs) forming photosensitizing NPs, has emerged as a therapeutic strategy to improve PS tumor targeting, to protect PS from deactivation reactions and to enhance both PS solubility and circulation time. Since association with NPs usually alters PS photophysical and photochemical properties, photosensitizing NPs are an important tool to modulate ROS generation. Depending on the design of the photosensitizing NP, i.e., type of PS, the NP material and the method applied for the construction of the photosensitizing NP, the deactivation routes of the excited state can be controlled, allowing the generation of either singlet oxygen or other reactive oxygen species (ROS). Controlling the type of generated ROS is desirable not only in biomedical applications, as in Photodynamic Therapy where the type of ROS affects therapeutic efficiency, but also in other technological relevant fields like energy conversion, where the electron and energy transfer processes are necessary to increase the efficiency of photoconversion cells. The current review highlights some of the recent developments in the design of Photosensitizing NPs aimed at modulating the primary photochemical events after light absorption. PMID:26075198

  16. Photosensitizing Nanoparticles and The Modulation of Reactive Oxygen Species generation

    NASA Astrophysics Data System (ADS)

    Tada, Dayane; Baptista, Mauricio

    2015-05-01

    The association of PhotoSensitizer (PS) molecules with nanoparticles (NPs) forming photosensitizing NPs, has emerged as a therapeutic strategy to improve PS tumor targeting, to protect PS from deactivation reactions and to enhance both PS solubility and circulation time. Since association with NPs usually alters PS photophysical and photochemical properties, photosensitizing NPs are an important tool to modulate reactive oxygen species (ROS) generation. Depending on the design of the photosensitizing NP, i.e., type of PS, the NP material and the method applied for the construction of the photosensitizing NP, the deactivation routes of the excited state can be controlled, allowing the generation of either singlet oxygen or other ROS. Controlling the type of generated ROS is desirable not only in biomedical applications, as in Photodynamic Therapy where the type of ROS affects therapeutic efficiency, but also in other technological relevant fields like energy conversion, where the electron and energy transfer processes are necessary to increase the efficiency of photoconversion cells. The current review highlights some of the recent developments in the design of Photosensitizing NPs aimed at modulating the primary photochemical events after light absorption.

  17. Generation of Coherent X-Ray Radiation Through Modulation Compression

    SciTech Connect

    Qiang, Ji; Wu, Juhao

    2010-12-14

    In this letter, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulators, a laser chirper and two bunch compressors to generate a prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. The initial modulation energy wavelength can be compressed by a factor of 1 + h{sub b}R{sub 56}{sup a} phase space, where h{sub b} is the energy bunch length chirp introduced by the laser chirper, R{sub 56}{sup a} is the momentum compaction factor of the first bunch compressor. As an illustration, we present an example to generate more than 400 MW, 170 atto-seconds pulse, 1 nm coherent X-ray radiation using a 60 Ampere electron beam out. of the linac and 200 nm laser seed. Both the final wavelength and the radiation pulse length in the proposed scheme are tunable by adjusting the compression factor and the laser parameters.

  18. Digital phantoms generated by spectral and spatial light modulators

    PubMed Central

    Chon, Bonghwan; Tokumasu, Fuyuki; Lee, Ji Youn; Allen, David W.; Rice, Joseph P.; Hwang, Jeeseong

    2015-01-01

    Abstract. A hyperspectral image projector (HIP) based on liquid crystal on silicon spatial light modulators is explained and demonstrated to generate data cubes. The HIP-constructed data cubes are three-dimensional images of the spatial distribution of spectrally resolved abundances of intracellular light-absorbing oxyhemoglobin molecules in single erythrocytes. Spectrally and spatially resolved image data indistinguishable from the real scene may be used as standard data cubes, so-called digital phantoms, to calibrate image sensors and validate image analysis algorithms for their measurement quality, performance consistency, and interlaboratory comparisons for quantitative biomedical imaging applications. PMID:26502383

  19. Digital phantoms generated by spectral and spatial light modulators.

    PubMed

    Chon, Bonghwan; Tokumasu, Fuyuki; Lee, Ji Youn; Allen, David W; Rice, Joseph P; Hwang, Jeeseong

    2015-01-01

    A hyperspectral image projector (HIP) based on liquid crystal on silicon spatial light modulators is explained and demonstrated to generate data cubes. The HIP-constructed data cubes are three-dimensional images of the spatial distribution of spectrally resolved abundances of intracellular light-absorbing oxyhemoglobin molecules in single erythrocytes. Spectrally and spatially resolved image data indistinguishable from the real scene may be used as standard data cubes, so-called digital phantoms, to calibrate image sensors and validate image analysis algorithms for their measurement quality, performance consistency, and interlaboratory comparisons for quantitative biomedical imaging applications.

  20. Digital phantoms generated by spectral and spatial light modulators

    NASA Astrophysics Data System (ADS)

    Chon, Bonghwan; Tokumasu, Fuyuki; Lee, Ji Youn; Allen, David W.; Rice, Joseph P.; Hwang, Jeeseong

    2015-12-01

    A hyperspectral image projector (HIP) based on liquid crystal on silicon spatial light modulators is explained and demonstrated to generate data cubes. The HIP-constructed data cubes are three-dimensional images of the spatial distribution of spectrally resolved abundances of intracellular light-absorbing oxyhemoglobin molecules in single erythrocytes. Spectrally and spatially resolved image data indistinguishable from the real scene may be used as standard data cubes, so-called digital phantoms, to calibrate image sensors and validate image analysis algorithms for their measurement quality, performance consistency, and interlaboratory comparisons for quantitative biomedical imaging applications.

  1. Electrical Power Generation by Mechanically Modulating Electrical Double Layers

    NASA Astrophysics Data System (ADS)

    Lee, Dongyun; Moon, Jong Kyun; Jeong, Jaeki; Pak, Hyuk Kyu

    2012-11-01

    Many objects in contact with a liquid acquire some electronic charges on their surfaces. These charges on the surface attract counter ions from the liquid phase. This complex system is called electrical double layer (EDL). Since its geometry and structure is similar to an electric capacitor, it is also called an electrical double layer capacitor (EDLC). In this work we studied two EDLCs formed in a liquid droplet bridge between two parallel solid conducting plates. We found that when the bridge height was mechanically modulated, each EDLC was continuously charged and discharged generating an AC electric current across the plates. The results of this experiment can be useful for constructing a micro-fluidic power generation.

  2. Contextual modulation of a multifunctional central pattern generator.

    PubMed

    Ramakrishnan, Siddharth; Arnett, Bridgette; Murphy, A Don

    2014-11-01

    The multifunctional buccal central pattern generator in snails, which controls different oral behaviors, has been well characterized. In this work we propose a role for the group of about 40 electrotonically coupled buccal A cluster cells as a context-dependant switch for the buccal central pattern generator, modulating motor patterns that elicit different oral behaviors. We characterize these cells based on location and morphology, and provide evidence for their selective activation under two different stimuli - Listerine perfusion and intestinal nerve stimulation - triggering buccal motor patterns putatively underlying egestion and substrate cleaning. A new role for these electrotonically coupled buccal A cluster neurons is shown. They serve as a context-dependant switch that alters buccal motor patterns depending on input stimuli, thereby eliciting the appropriate behavioral response.

  3. From Modules to a Generator: An Integrated Heat Exchanger Concept for Car Applications of a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Bosch, Henry

    2016-03-01

    A heat exchanger concept for a thermoelectric generator with integrated planar modules for passenger car applications is introduced. The module housings, made of deep drawn stainless steel sheet metal, are brazed onto the exhaust gas channel to achieve an optimal heat transfer on the hot side of the modules. The cooling side consists of winding fluid channels, which are mounted directly onto the cold side of the modules. Only a thin foil separates the cooling media from the modules for an almost direct heat contact on the cooling side. Thermoelectric generators with up to 20 modules made of PbTe and Bi2Te3, respectively, are manufactured and tested on a hot gas generator to investigate electrical power output and performance of the thermoelectric generator. The proof of concept of the light weight heat exchanger design made of sheet metal with integrated modules is positively accomplished.

  4. Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems

    NASA Technical Reports Server (NTRS)

    Ramakumar, R.; Bahrami, K.

    1981-01-01

    This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

  5. System and Method for Generating a Frequency Modulated Linear Laser Waveform

    NASA Technical Reports Server (NTRS)

    Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)

    2014-01-01

    A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

  6. Structured elves: Modulation by convectively generated gravity waves

    NASA Astrophysics Data System (ADS)

    Yue, Jia; Lyons, Walter A.

    2015-02-01

    We report on a markedly striated elve (Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Source) (a "tiger elve") observed using an intensified high-speed Phantom camera system at the Yucca Ridge Field Station near Fort Collins, Colorado, on the night of 12 June 2013. This elve was induced by a 204 kA positive cloud-to-ground lightning flash within a mesoscale convective system in western South Dakota. A halo and a sprite followed the elve. The banded structure in the elve was aligned with convectively generated gravity waves (CGGWs) independently observed by a collocated color near-infrared camera. Assuming the height of the OH layer and elve both to be 85 km, photogrammetry allowed projection of the elve and the CGGWs onto the same geographic map. The tiger elve stripes approximately overlay on the troughs (dark bands) of CGGWs. This is consistent with model predictions that the ionization rate in the D region ionosphere is inversely proportional to the air density, which is modulated by the CGGWs.

  7. Next Generation Space Telescope Integrated Science Module Data System

    NASA Technical Reports Server (NTRS)

    Schnurr, Richard G.; Greenhouse, Matthew A.; Jurotich, Matthew M.; Whitley, Raymond; Kalinowski, Keith J.; Love, Bruce W.; Travis, Jeffrey W.; Long, Knox S.

    1999-01-01

    The Data system for the Next Generation Space Telescope (NGST) Integrated Science Module (ISIM) is the primary data interface between the spacecraft, telescope, and science instrument systems. This poster includes block diagrams of the ISIM data system and its components derived during the pre-phase A Yardstick feasibility study. The poster details the hardware and software components used to acquire and process science data for the Yardstick instrument compliment, and depicts the baseline external interfaces to science instruments and other systems. This baseline data system is a fully redundant, high performance computing system. Each redundant computer contains three 150 MHz power PC processors. All processors execute a commercially available real time multi-tasking operating system supporting, preemptive multi-tasking, file management and network interfaces. These six processors in the system are networked together. The spacecraft interface baseline is an extension of the network, which links the six processors. The final selection for Processor busses, processor chips, network interfaces, and high-speed data interfaces will be made during mid 2002.

  8. Supercontinuum and rogue soliton generation by induced modulational instability in photonic crystal fibre

    NASA Astrophysics Data System (ADS)

    Yang, Hua; Chen, Nengsong; Wang, Boyan; Tang, Pinghua; Zeng, Qilin

    2016-08-01

    We present an approach that enables active control of supercontinuum (SC) and rogue soliton (RS) generation through the modulation of a 500 fs input pulse by numerical simulations. The induced modulational instability contributes to the initial comb-like SC generation, which is fundamentally different from SC initiated by high-order soliton fission. The output spectrum shows great dependence on modulation frequencies and depths. It is interesting that we can manipulate the RS generation by adjusting the modulation parameters. And we also demonstrate the conditions which can be beneficial to RS generation: (i) very weak or large values of modulation depth; (ii) seeding in the vicinity of the peak of the modulational instability gain spectrum. Although RS degrades the smoothness of the SC, it is of great significance in the generation of tailored SC.

  9. 40G and 100G modules enable next generation networks

    NASA Astrophysics Data System (ADS)

    Hong, Jin; Schmidt, Ted; Traverso, Matt; Yoshikazu, Era

    2009-11-01

    With the wide scale deployment of 40Gbps in carrier networks underway and 100Gbps products on the horizon, 40Gbps and 100Gbps modules based on Multi Source Agreements (MSA) are gaining considerable interest and market acceptance. This paper discusses developments in 40Gbps and 100Gbps line side DWDM MSA modules and CFP based client side MSA modules as suppliers strive to address various system and network applications.

  10. Design, fabrication, test qualification and price analysis of a third generation solar cell module

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The design, fabrication, test, and qualification of a third generation intermediate load solar cell module are presented. A technical discussion of the detailed module design, preliminary design review, design modifications, and environmental testing are included. A standardized pricing system is utilized to establish the cost competitiveness of this module design.

  11. Polarization-Modulated Second Harmonic Generation Microscopy in Collagen

    SciTech Connect

    Stoller, P C

    2002-09-30

    Collagen is a key structural protein in the body; several pathological conditions lead to changes in collagen. Among imaging modalities that can be used in vivo, second harmonic generation (SHG) microscopy has a key advantage: it provides {approx}1 {micro}m resolution information about collagen structure as a function of depth. A new technique--polarization-modulated SHG--is presented: it permits simultaneous measurement of collagen orientation, of a lower bound on the magnitude of the second order nonlinear susceptibility tensor, and of the ratio of the two independent elements in this tensor. It is applied to characterizing SHG in collagen and to determining effects of biologically relevant changes in collagen structure. The magnitude of the second harmonic signal in two dimensional images varies with position even in structurally homogeneous tissue; this phenomenon is due to interference between second harmonic light generated by neighboring fibrils, which are randomly oriented parallel or anti-parallel to each other. Studies in which focal spot size was varied indicated that regions where fibrils are co-oriented are less than {approx}1.5 {micro}m in diameter. A quartz reference was used to determine the spot size as well as a lower limit (d{sub xxx} > 0.3 pm/V) for the magnitude of the second order nonlinear susceptibility. The ratio of the two independent tensor elements ranged between d{sub XYY}/d{sub XXX} = 0.60 and 0.75. SHG magnitude alone was not useful for identifying structural anomalies in collagenous tissue. Instead, changes in the polarization dependence of SHG were used to analyze biologically relevant perturbations in collagen structure. Changes in polarization dependence were observed in dehydrated samples, but not in highly crosslinked samples, despite significant alterations in packing structure. Complete thermal denaturation and collagenase digestion produced samples with no detectable SHG signal. Collagen orientation was measured in thin

  12. Generation of Optical Millimeter Wave Using Two Cascaded Polarization Modulators Based on Frequency Octupling Without Filtering

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Ma, Jianxin; Zhang, Ruijiao; Xin, Xiangjun; Zhang, Junyi

    2015-11-01

    An approach to generate an optical millimeter wave is introduced with frequency octupling using two cascaded polarization modulators followed by polarizers, respectively. By adjusting the modulation indexes of polarization modulators, only the ±4th-order sidebands are generated with a pure spectrum. Since no filter is needed, the proposed technique can be used to generate a frequency-tunable millimeter wave with a large frequency-tunable range. To prove the feasibility of the proposed approach, a simulation is conducted to generate an 80-GHz millimeter wave, and then its transmission performance is checked.

  13. A Novel Approach to Photonic Generation and Modulation of Ultra-Wideband Pulses

    NASA Astrophysics Data System (ADS)

    Xiang, Peng; Guo, Hao; Chen, Dalei; Zhu, Huatao

    2016-01-01

    A novel approach to photonic generation of ultra-wideband (UWB) signals is proposed in this paper. The proposed signal generator is capable of generating UWB doublet pulses with flexible reconfigurability, and many different pulse modulation formats, including the commonly used pulse-position modulation (PPM) and bi-phase modulation (BPM) can be realized. Moreover, the photonic UWB pulse generator is capable of generating UWB signals with a tunable spectral notch-band, which is desirable to realize the interference avoidance between UWB and other narrow band systems, such as Wi-Fi. A mathematical model describing the proposed system is developed and the generation of UWB signals with different modulation formats is demonstrated via computer simulations.

  14. UWB doublet signal generation and modulation based on DFB laser under optical pulses injection

    NASA Astrophysics Data System (ADS)

    Chen, Dalei; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Zhou, Hua; Zhao, Jiyong; Huang, Long; Zhu, Huatao; Wang, Peng

    2016-05-01

    In this paper, a novel scheme to generate ultra-wideband (UWB) doublet signals based on the cross-gain modulation (XGM) effect in the DFB lasers is proposed and experimentally demonstrated, the modulation and transmission of the generated UWB doublet signals are also researched. In the proposed system, a gain-switched laser (GSL) is used as a master laser (ML) and the optical pulses from the ML are optically injected into two paralleled DFB lasers, which are used as slave lasers (SL). Then the outputs from the SLs are detected by a balanced photodiode (BPD) to generate the Bi-phased UWB signals. By properly setting the system parameters, UWB signals with various modulation formats such as on-off keying (OOK), pulse amplitude modulation (PAM) as well as the phase-shift keying (PSK) can be generated. In addition, fiber transmission of the modulated UWB signals is also experimentally investigated.

  15. Distortion generated in angle-modulation systems by phased arrays

    NASA Technical Reports Server (NTRS)

    Rogers, J. D.; Lagrone, A. H.; Fowler, J.

    1973-01-01

    The magnitude and characteristics of distortion produced in demodulated signals by corporate-fed phased arrays are reviewed. Graphs depicting distortion, plotted as a function of signal characteristics and array geometry, display the effects of large arrays on broadband signals. These curves show that distortion in angle-modulation systems is more a function of modulation index than of bandwidth. The data presented provide a basis for predicting distortion levels in practical array systems and for extending analyses to other signal-array configurations.

  16. Endurance testing of first generation (Block 1) commercial solar cell modules

    NASA Technical Reports Server (NTRS)

    Anagnostou, E.; Forestieri, A. F.

    1978-01-01

    To determine lifetimes of the first generation (Block 1) commercial solar cell modules used in solar cell arrays, a program was initiated to expose these modules to a range of environments. The conditions endured by these modules encompassed hot and dry, hot and humid, tropical rain forests, sea-air, urban industrial and urban clean. Exposures were for periods up to 1 year. The effect of outdoor exposure on the performance of the modules was determined using current-voltage curves. Short-circuit current (I sub sc) and maximum power (P sub max) were the parameters monitored. In all cases, there was a loss of performance of the modules with outdoor exposure.

  17. Ultrawideband monocycle pulse generation based on polarization modulator and low speed electrical NRZ signal

    NASA Astrophysics Data System (ADS)

    Sun, Guodan; Zhang, Qiufang; Wang, Quan

    2015-07-01

    A novel ultrawideband (UWB) monocycle pulse generation system by modulating a polarization modulator (PolM) with a low speed electrical nonreturn-to-zero (NRZ) signal is proposed, which significantly reduce the bandwidth requirement of the driving signal. At each bit transition of the input NRZ signal, two polarity-reversed Gaussian pulses are generated. By properly setting the delay between these two Gaussian pulses, an optical UWB monocycle pulse can be generated. Biphase modulation (BPM) can be realized by electrically switching the polarization direction at the output of PolM, if an electrically tunable arbitrary wave plate (AWP) is employed.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Phase matching of high order harmonic generation using dynamic phase modulation caused by a non-collinear modulation pulse

    DOEpatents

    Cohen, Oren; Kapteyn, Henry C.; Mumane, Margaret M.

    2010-02-16

    Phase matching high harmonic generation (HHG) uses a single, long duration non-collinear modulating pulse intersecting the driving pulse. A femtosecond driving pulse is focused into an HHG medium (such as a noble gas) to cause high-harmonic generation (HHG), for example in the X-ray region of the spectrum, via electrons separating from and recombining with gas atoms. A non-collinear pulse intersects the driving pulse within the gas, and modulates the field seen by the electrons while separated from their atoms. The modulating pulse is low power and long duration, and its frequency and amplitude is chosen to improve HHG phase matching by increasing the areas of constructive interference between the driving pulse and the HHG, relative to the areas of destructive interference.

  20. Status Update on the Second-Generation ILC Marx Modulator Prototype

    SciTech Connect

    Kemp, Mark A.; Benwell, Andrew; Burkhart, Craig; Larsen, Ray; MacNair, David; Nguyen, Minh; Olsen, Jeff; /SLAC

    2010-08-26

    This paper is a status update of the SLAC P2 Marx. This Marx-topology klystron modulator is a second-generation modulator which builds upon experience gained from the SLAC P1 Marx. There are several fundamental differences between these modulators including the correction scheme, bus voltages, and the control system architecture. These differences, along with preliminary experimental results and the schedule for further development, are detailed in this paper.

  1. First and second generation γ-secretase modulators (GSMs) modulate amyloid-β (Aβ) peptide production through different mechanisms.

    PubMed

    Borgegard, Tomas; Juréus, Anders; Olsson, Fredrik; Rosqvist, Susanne; Sabirsh, Alan; Rotticci, Didier; Paulsen, Kim; Klintenberg, Rebecka; Yan, Hongmei; Waldman, Magnus; Stromberg, Kia; Nord, Johan; Johansson, Jonas; Regner, Anna; Parpal, Santiago; Malinowsky, David; Radesater, Ann-Cathrin; Li, Tingsheng; Singh, Rajeshwar; Eriksson, Hakan; Lundkvist, Johan

    2012-04-01

    γ-Secretase-mediated cleavage of amyloid precursor protein (APP) results in the production of Alzheimer disease-related amyloid-β (Aβ) peptides. The Aβ42 peptide in particular plays a pivotal role in Alzheimer disease pathogenesis and represents a major drug target. Several γ-secretase modulators (GSMs), such as the nonsteroidal anti-inflammatory drugs (R)-flurbiprofen and sulindac sulfide, have been suggested to modulate the Alzheimer-related Aβ production by targeting the APP. Here, we describe novel GSMs that are selective for Aβ modulation and do not impair processing of Notch, EphB2, or EphA4. The GSMs modulate Aβ both in cell and cell-free systems as well as lower amyloidogenic Aβ42 levels in the mouse brain. Both radioligand binding and cellular cross-competition experiments reveal a competitive relationship between the AstraZeneca (AZ) GSMs and the established second generation GSM, E2012, but a noncompetitive interaction between AZ GSMs and the first generation GSMs (R)-flurbiprofen and sulindac sulfide. The binding of a (3)H-labeled AZ GSM analog does not co-localize with APP but overlaps anatomically with a γ-secretase targeting inhibitor in rodent brains. Combined, these data provide compelling evidence of a growing class of in vivo active GSMs, which are selective for Aβ modulation and have a different mechanism of action compared with the original class of GSMs described.

  2. First and Second Generation γ-Secretase Modulators (GSMs) Modulate Amyloid-β (Aβ) Peptide Production through Different Mechanisms

    PubMed Central

    Borgegard, Tomas; Juréus, Anders; Olsson, Fredrik; Rosqvist, Susanne; Sabirsh, Alan; Rotticci, Didier; Paulsen, Kim; Klintenberg, Rebecka; Yan, Hongmei; Waldman, Magnus; Stromberg, Kia; Nord, Johan; Johansson, Jonas; Regner, Anna; Parpal, Santiago; Malinowsky, David; Radesater, Ann-Cathrin; Li, Tingsheng; Singh, Rajeshwar; Eriksson, Hakan; Lundkvist, Johan

    2012-01-01

    γ-Secretase-mediated cleavage of amyloid precursor protein (APP) results in the production of Alzheimer disease-related amyloid-β (Aβ) peptides. The Aβ42 peptide in particular plays a pivotal role in Alzheimer disease pathogenesis and represents a major drug target. Several γ-secretase modulators (GSMs), such as the nonsteroidal anti-inflammatory drugs (R)-flurbiprofen and sulindac sulfide, have been suggested to modulate the Alzheimer-related Aβ production by targeting the APP. Here, we describe novel GSMs that are selective for Aβ modulation and do not impair processing of Notch, EphB2, or EphA4. The GSMs modulate Aβ both in cell and cell-free systems as well as lower amyloidogenic Aβ42 levels in the mouse brain. Both radioligand binding and cellular cross-competition experiments reveal a competitive relationship between the AstraZeneca (AZ) GSMs and the established second generation GSM, E2012, but a noncompetitive interaction between AZ GSMs and the first generation GSMs (R)-flurbiprofen and sulindac sulfide. The binding of a 3H-labeled AZ GSM analog does not co-localize with APP but overlaps anatomically with a γ-secretase targeting inhibitor in rodent brains. Combined, these data provide compelling evidence of a growing class of in vivo active GSMs, which are selective for Aβ modulation and have a different mechanism of action compared with the original class of GSMs described. PMID:22334705

  3. Generation of ELF and VLF waves by modulated HF heating of the polar electrojet

    NASA Astrophysics Data System (ADS)

    Stubbe, P.; Kopka, H.; Rietveld, M. T.; Dowden, R. L.

    1982-02-01

    Modulated heating of the lower ionosphere, with modulation frequencies in the ELF and VLF range, gives rise to a corresponding modulation of the electron temperature and, thus, of the electrical conductivity. If a polar electrojet current exists, the current density is modulated, and an ELF or VLF signal is generated. Experiments were performed to test this mechanism, using the new ionospheric heating facility at Ramfjordmoen, Norway. It was found that this mechanism is sensitive in the full ELF range and for VLF frequencies exceeding 7 kHz, the upper limit of the VLF receiver used.

  4. Method and split cavity oscillator/modulator to generate pulsed particle beams and electromagnetic fields

    DOEpatents

    Clark, M. Collins; Coleman, P. Dale; Marder, Barry M.

    1993-01-01

    A compact device called the split cavity modulator whose self-generated oscillating electromagnetic field converts a steady particle beam into a modulated particle beam. The particle beam experiences both signs of the oscillating electric field during the transit through the split cavity modulator. The modulated particle beam can then be used to generate microwaves at that frequency and through the use of extractors, high efficiency extraction of microwave power is enabled. The modulated beam and the microwave frequency can be varied by the placement of resistive wires at nodes of oscillation within the cavity. The short beam travel length through the cavity permit higher currents because both space charge and pinching limitations are reduced. The need for an applied magnetic field to control the beam has been eliminated.

  5. Method and split cavity oscillator/modulator to generate pulsed particle beams and electromagnetic fields

    DOEpatents

    Clark, M.C.; Coleman, P.D.; Marder, B.M.

    1993-08-10

    A compact device called the split cavity modulator whose self-generated oscillating electromagnetic field converts a steady particle beam into a modulated particle beam. The particle beam experiences both signs of the oscillating electric field during the transit through the split cavity modulator. The modulated particle beam can then be used to generate microwaves at that frequency and through the use of extractors, high efficiency extraction of microwave power is enabled. The modulated beam and the microwave frequency can be varied by the placement of resistive wires at nodes of oscillation within the cavity. The short beam travel length through the cavity permit higher currents because both space charge and pinching limitations are reduced. The need for an applied magnetic field to control the beam has been eliminated.

  6. Single module pressurized fuel cell turbine generator system

    DOEpatents

    George, Raymond A.; Veyo, Stephen E.; Dederer, Jeffrey T.

    2001-01-01

    A pressurized fuel cell system (10), operates within a common pressure vessel (12) where the system contains fuel cells (22), a turbine (26) and a generator (98) where preferably, associated oxidant inlet valve (52), fuel inlet valve (56) and fuel cell exhaust valve (42) are outside the pressure vessel.

  7. Continuous third harmonic generation in a terahertz driven modulated nanowire

    NASA Astrophysics Data System (ADS)

    Hamilton, Kathleen E.; Kovalev, Alexey A.; De, Amrit; Pryadko, Leonid P.

    2015-06-01

    We consider the possibility of observing continuous third-harmonic generation using a strongly driven, single-band one-dimensional metal. In the absence of scattering, the quantum efficiency of frequency tripling for such a system can be as high as 93%. Combining the Floquet quasi-energy spectrum with the Keldysh Green's function technique, we derive a semiclassical master equation for a one-dimensional band of strongly and rapidly driven electrons in the presence of weak scattering by phonons. The power absorbed from the driving field is continuously dissipated by phonon modes, leading to a quasi-equilibrium in the electron distribution. We use the Kronig-Penney model with varying effective mass to establish the growth parameters of an InAs/InP nanowire near optimal for third harmonic generation at terahertz frequency range.

  8. Continuous third harmonic generation in a terahertz driven modulated nanowire

    SciTech Connect

    Hamilton, Kathleen E. De, Amrit; Pryadko, Leonid P.; Kovalev, Alexey A.

    2015-06-07

    We consider the possibility of observing continuous third-harmonic generation using a strongly driven, single-band one-dimensional metal. In the absence of scattering, the quantum efficiency of frequency tripling for such a system can be as high as 93%. Combining the Floquet quasi-energy spectrum with the Keldysh Green's function technique, we derive a semiclassical master equation for a one-dimensional band of strongly and rapidly driven electrons in the presence of weak scattering by phonons. The power absorbed from the driving field is continuously dissipated by phonon modes, leading to a quasi-equilibrium in the electron distribution. We use the Kronig-Penney model with varying effective mass to establish the growth parameters of an InAs/InP nanowire near optimal for third harmonic generation at terahertz frequency range.

  9. Integrable turbulence generated from modulational instability of cnoidal waves

    NASA Astrophysics Data System (ADS)

    Agafontsev, D. S.; Zakharov, V. E.

    2016-11-01

    We study numerically the nonlinear stage of the modulational instability (MI) of cnoidal waves in the framework of the focusing one-dimensional nonlinear Schrödinger (NLS) equation. Cnoidal waves are exact periodic solutions of the NLS equation which can be represented as the lattices of overlapping solitons. The MI of these lattices leads to the development of ‘integrable turbulence’ (Zakharov 2009 Stud. Appl. Math. 122 219–34). We study the major characteristics of turbulence for the dn-branch of cnoidal waves and demonstrate how these characteristics depend on the degree of ‘overlapping’ between the solitons within the cnoidal wave. Integrable turbulence, which develops from the MI of the dn-branch of cnoidal waves, asymptotically approaches its stationary state in an oscillatory way. During this process, kinetic and potential energies oscillate around their asymptotic values. The amplitudes of these oscillations decay with time as {{t}-α} , 1<α <1.5 , the phases contain nonlinear phase shift decaying as t ‑1/2, and the frequency of the oscillations is equal to the double maximal growth rate of the MI, s=2{γ\\max} . In the asymptotic stationary state, the ratio of potential to kinetic energy is equal to  ‑2. The asymptotic PDF of the wave intensity is close to the exponential distribution for cnoidal waves with strong overlapping, and is significantly non-exponential for cnoidal waves with weak overlapping of the solitons. In the latter case, the dynamics of the system reduces to two-soliton collisions, which occur at an exponentially small rate and provide an up to two-fold increase in amplitude compared with the original cnoidal wave. For all cnoidal waves of the dn-branch, the rogue waves at the time of their maximal elevation have a quasi-rational profile similar to that of the Peregrine solution.

  10. Safety issues and prospects for future generations of PPAR modulators.

    PubMed

    Rubenstrunk, Anne; Hanf, Rémy; Hum, Dean W; Fruchart, Jean-Charles; Staels, Bart

    2007-08-01

    development of new PPAR agonists. The selective modulation of PPAR activities is a promising approach to develop new drugs with preserved efficacy but diminished adverse effects.

  11. Species-specific modulation of pattern-generating circuits.

    PubMed

    Meyrand, P; Faumont, S; Simmers, J; Christie, A E; Nusbaum, M P

    2000-07-01

    Phylogenetic comparison can reveal general principles governing the organization and neuromodulation of neural networks. Suitable models for such an approach are the pyloric and gastric motor networks of the crustacean stomatogastric ganglion (STG). These networks, which have been well studied in several species, are extensively modulated by projection neurons originating in higher-order ganglia. Several of these have been identified in different decapod species, including the paired modulatory proctolin neuron (MPN) in the crab Cancer borealis [Nusbaum & Marder (1989) J. Neurosci., 9,1501-1599; Nusbaum & Marder (1989), J. Neurosci., 9, 1600-1607] and the apparently equivalent neuron pair, called GABA (gamma-aminobutyric acid) neurons 1 and 2 (GN1/2), in the lobster Homarus gammarus [Cournil et al. (1990) J. Neurocytol., 19, 478-493]. The morphologies of MPN and GN1/2 are similar, and both exhibit GABA-immunolabelling. However, unlike MPN, GN1/2 does not contain the peptide transmitter proctolin. Instead, GN1/2, but not MPN, is immunoreactive for the neuropeptides related to cholecystokinin (CCK) and FLRFamide. Nonetheless, GN1/2 excitation of the lobster pyloric rhythm is similar to the proctolin-mediated excitation of the crab pyloric rhythm by MPN. In contrast, GN1/2 and MPN both use GABA but produce opposite effects on the gastric mill rhythm. While MPN stimulation produces a GABA-mediated suppression of the gastric rhythm [Blitz & Nusbaum (1999) J. Neurosci., 19, 6774-6783], GN1/2 activates or enhances gastric rhythmicity. These results highlight the care needed when generalizing neuronal organization and function across related species. Here we show that the 'same' neuron in different species does not contain the same neurotransmitter complement, nor does it exert all of the same effects on its postsynaptic targets. Conversely, a different transmitter phenotype is not necessarily associated with a qualitative change in the way that a modulatory neuron

  12. Photonic RF vector signal generation with enhanced spectral efficiency using precoded double single-sideband modulation.

    PubMed

    Wang, Yuanquan; Chien, Hung-Chang; Guo, HaiChao; Yu, Jianjun; Chang, Gee-Kung; Chi, Nan

    2016-06-01

    In this study, a novel photonic vector signal at frequency (RF) bands generation scheme based on the beating of double single sidebands (SSBs) is proposed and experimentally demonstrated. The double SSBs carry separate constant- or multi-amplitude quadrature-amplitude-modulation vector signals are generated from a single I/Q modulator. By adopting phase and amplitude precoding, different constellations can be generated, such as 3-ary phase-shift keying (PSK), 4-PSK, 7-PSK, 8-PSK, and so on. In this work, 10-Gbaud 7-PSK vector signal generation at 20 GHz enabled by two precoded 4-PSK SSB signals via a single I/Q modulator is theoretically and experimentally investigated. Compared to a single-drive Mach-Zehnder modulator or conventional I/Q modulator-based photonic vector signal generation scheme, the spectrum efficiency can be doubled. Differential coding is also implemented at the transmitter side for accurate demodulation of 7-PSK into two 4-PSK signals. The bit-error ratio for 10-Gbaud 7-PSK vector signals can be under hard-decision forward-error-correction threshold of 3.8×10-3 after 10 km standard single-mode fiber transmission.

  13. Analysis of the modulation impairments in optical sideband injection locking for millimeter-wave signal generation

    NASA Astrophysics Data System (ADS)

    Aldaya, Ivan; Campuzano, Gabriel; Castañón, Gerardo

    2014-03-01

    In optical sideband injection locking (OSBIL) transmitters, the millimeter-wave (mm-wave) signal is generated heterodyning the phase-correlated outputs of two lasers, resulting in mm-wave signals with high frequency purity. Additionally, OSBIL is a cost-effective mm-wave generation technique since it does not require any external broad-bandwidth optical modulator. However, the non-linear distortion and the noise of the directly modulated laser limit its performance. This paper studies for the first time, the modulation impairments in terms of the injection conditions considering the sideband asymmetry that persists in heterodyne generation techniques. Signal-to-noise ratio and nonlinear distortion are analyzed through simulations showing different performance for upper and lower modulation sidebands and its dependence on the intermediate frequency. We show that the noise spectral density is reduced setting up the injected laser at (i) low power injection ratios and using a low intermediate frequency or (ii) higher power injection ratios, a negative frequency detuning, and a higher intermediate frequency. Regarding nonlinearities, we show that its effect on the lower modulation sideband is less significant than in the upper sideband. This impairment analysis is used to optimize the generation of OFDM signals in the 60-GHz band, achieving 2.5 Gbps generation with a spectral efficiency of 3.4 bps/Hz.

  14. W-shaped solitons generated from a weak modulation in the Sasa-Satsuma equation.

    PubMed

    Zhao, Li-Chen; Li, Sheng-Chang; Ling, Liming

    2016-03-01

    We study rational solutions of continuous wave backgrounds with the critical frequencies of the Sasa-Satsuma equation, which can be used to describe the evolution of the optical field in a nonlinear fiber with some high-order effects. We find a striking dynamical process that two W-shaped solitons are generated from a weak modulation signal on the continuous wave backgrounds. This provides a possible way to obtain stable high-intensity pulses from a low-intensity continuous wave background. The process involves both modulational instability and modulational stability regimes, in contrast to the rogue waves and W-shaped solitons reported before which involve modulational instability and stability, respectively. Furthermore, we present a phase diagram on a modulational instability spectrum plane for the fundamental nonlinear localized waves obtained already in the Sasa-Satsuma equation. The interactions between different types of nonlinear localized waves are discussed based on the phase diagram.

  15. W-shaped solitons generated from a weak modulation in the Sasa-Satsuma equation.

    PubMed

    Zhao, Li-Chen; Li, Sheng-Chang; Ling, Liming

    2016-03-01

    We study rational solutions of continuous wave backgrounds with the critical frequencies of the Sasa-Satsuma equation, which can be used to describe the evolution of the optical field in a nonlinear fiber with some high-order effects. We find a striking dynamical process that two W-shaped solitons are generated from a weak modulation signal on the continuous wave backgrounds. This provides a possible way to obtain stable high-intensity pulses from a low-intensity continuous wave background. The process involves both modulational instability and modulational stability regimes, in contrast to the rogue waves and W-shaped solitons reported before which involve modulational instability and stability, respectively. Furthermore, we present a phase diagram on a modulational instability spectrum plane for the fundamental nonlinear localized waves obtained already in the Sasa-Satsuma equation. The interactions between different types of nonlinear localized waves are discussed based on the phase diagram. PMID:27078352

  16. Earth abundant thin film technology for next generation photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Alapatt, Githin Francis

    With a cumulative generation capacity of over 100 GW, Photovoltaics (PV) technology is uniquely poised to become increasingly popular in the coming decades. Although, several breakthroughs have propelled PV technology, it accounts for only less than 1% of the energy produced worldwide. This aspect of the PV technology is primarily due to the somewhat high cost per watt, which is dependent on the efficiency of the PV cells as well as the cost of manufacturing and installing them. Currently, the efficiency of the PV conversion process is limited to about 25% for commercial terrestrial cells; improving this efficiency can increase the penetration of PV worldwide rapidly. A critical review of all possibilities pursued in the public domain reveals serious shortcomings and manufacturing issues. To make PV generated power a reality in every home, a Multi-Junction Multi-Terminal (MJMT) PV architecture can be employed combining silicon and another earth abundant material. However, forming electronic grade thin films of earth abundant materials is a non-trivial challenge; without solving this, it is impossible to increase the overall PV efficiency. Deposition of Copper (I) Oxide, an earth abundant semiconducting material, was conducted using an optimized Photo assisted Chemical Vapor Deposition process. X-Ray Diffraction, Ellipsometry, Transmission Electron Microscopy, and Profilometry revealed that the films composed of Cu2O of about 90 nm thickness and the grain size was as large as 600 nm. This result shows an improvement in material properties over previously grown thin films of Cu2O. Measurement of I-V characteristics of a diode structure composed of the Cu2O indicates an increase in On/Off ratio to 17,000 from the previous best value of 800. These results suggest that the electronic quality of the thin films deposited using our optimized process to be better than the results reported elsewhere. Using this optimized thin film forming technique, it is now possible to

  17. Flexible generation of optical nonuniform bit-mapping signal based on InP transmitter module.

    PubMed

    Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Liu, Lei

    2014-01-15

    Flexible generation of an optical nonuniform bit-mapping signal based on an InP transmitter module is demonstrated. It can realize flexible bit mapping through the photonic modulation method, which can break the limitations of an electrical digital-to-analog convertor and field-programmable gate array. This module has potential to easily increase the signal rate or refine the granularity without electronics, which indicates it may be a future application to replace the traditional transmitter. The feasibility and performance of the proposed scheme are demonstrated in the experiment.

  18. New-generation concentrator modules based on cascade solar cells: Design and optical and thermal properties

    NASA Astrophysics Data System (ADS)

    Andreev, V. M.; Davidyuk, N. Yu.; Malevski, D. A.; Pan'chak, A. N.; Rumyantsev, V. D.; Sadchikov, N. A.; Chekalin, A. V.; Luque, A.

    2014-11-01

    New-generation concentrator modules use III-V nanoheterostructure cascade solar cells the efficiency of which can be raised to 50% for the number of cascades exceeding three. To obtain a high overall efficiency of photovoltaic conversion in power plants and extend their service time, it is necessary that the design of the modules be optimal in terms of optics and thermal engineering. In this work, main challenges in designing solar modules, such as optical concentration of radiation and residual heat removal, are considered. The results of pilot works that have been recently done in the Ioffe Physical Technical Institute are primarily reported.

  19. Generalized serial dilution module for monotonic and arbitrary microfluidic gradient generators.

    PubMed

    Lee, Kangsun; Kim, Choong; Ahn, Byungwook; Panchapakesan, Rajagopal; Full, Anthony R; Nordee, Ledum; Kang, Ji Yoon; Oh, Kwang W

    2009-03-01

    In this paper, we propose a generalized serial dilution module for universal microfluidic concentration gradient generators including N cascaded-mixing stages in a stepwise manner. Desired concentrations were generated by means of controlled volumetric mixing ratios of two merging solutions in each stage. The flow rates were adjusted by controlling channel length, which is proportional to fluidic resistance in each channel. A generalized mathematical model for generating any complex concentration and output flow rate gradients is presented based on the fact that there is an analogy between microfluidic circuits and electrical circuits. The pressure drop corresponds to a voltage drop, the flow rate to an electrical current, and the flow resistance to an electrical resistance. A simple equivalent electrical circuit model was generalized, and in the model each channel segment was represented by an electrical resistance. As a result of the mathematical modelling, the only variable parameter in the generalized serial dilution module was the channel length. By the use of the generalized serial dilution module with N = 4, three types of microfluidic gradient generators for linear, logarithmic and Gaussian gradients were successfully designed and tested. The proposed strategy is capable of generating universal monotonic gradients with a single module or arbitrary gradients with multiple modules ranging from linear to complex non-linear shapes of concentration gradients as well as arbitrary output flow rate gradients in a stepwise manner. The simple universal gradient generation technology using the generalized serial dilution module will find widespread use in the greater chemical and biological community, and address many challenges of gradient-dependent phenomena.

  20. Photonic generation of triangular waveform signals by using a dual-parallel Mach-Zehnder modulator.

    PubMed

    Li, J; Ning, T; Pei, L; Peng, W; Jia, N; Zhou, Q; Wen, X

    2011-10-01

    A photonic approach to generate triangular waveform signals is proposed and analyzed. With active bias control, two sub-MZMs (MZ-a and MZ-b) of a dual-parallel Mach-Zehnder modulator (DP-MZM) operate at minimum transmission point, leaving the main MZM (MZ-c) at quadrature transmission point. Triangular waveform can be observed by a parameter setting of modulation index. The proposal is first analyzed and then validated by simulation. The key significance of the scheme is that it is capable of generating triangular waveform signals via a sinusoid local oscillator.

  1. Pseudo-Random Modulation of a Laser Diode for Generating Ultrasonic Longitudinal Waves

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Anatasi, Robert F.

    2004-01-01

    Laser generated ultrasound systems have historically been more complicated and expensive than conventional piezoelectric based systems, and this fact has relegated the acceptance of laser based systems to niche applications for which piezoelectric based systems are less suitable. Lowering system costs, while improving throughput, increasing ultrasound signal levels, and improving signal-to-noise are goals which will help increase the general acceptance of laser based ultrasound. One current limitation with conventional laser generated ultrasound is a material s damage threshold limit. Increasing the optical power to generate more signal eventually damages the material being tested due to rapid, high heating. Generation limitations for laser based ultrasound suggests the use of pulse modulation techniques as an alternate generation method. Pulse modulation techniques can spread the laser energy over time or space, thus reducing laser power densities and minimizing damage. Previous experiments by various organizations using spatial or temporal pulse modulation have been shown to generate detectable surface, plate, and bulk ultrasonic waves with narrow frequency bandwidths . Using narrow frequency bandwidths improved signal detectability, but required the use of expensive and powerful lasers and opto-electronic systems. The use of a laser diode to generate ultrasound is attractive because of its low cost, small size, light weight, simple optics and modulation capability. The use of pulse compression techniques should allow certain types of laser diodes to produce usable ultrasonic signals. The method also does not need to be limited to narrow frequency bandwidths. The method demonstrated here uses a low power laser diode (approximately 150 mW) that is modulated by controlling the diode s drive current and the resulting signal is recovered by cross correlation. A potential application for this system which is briefly demonstrated is in detecting signals in thick

  2. Phosphate-modified analogues of m(7)GTP and m(7)Gppppm(7)G-Synthesis and biochemical properties.

    PubMed

    Ziemniak, Marcin; Kowalska, Joanna; Lukaszewicz, Maciej; Zuberek, Joanna; Wnek, Katarzyna; Darzynkiewicz, Edward; Jemielity, Jacek

    2015-09-01

    The synthesis and biochemical properties of 17 new mRNA cap analogues are reported. Six of these nucleotides are m(7)GTP derivatives, whereas 11 are 'two headed' tetraphosphate dinucleotides based on a m(7)Gppppm(7)G structure. The compounds contain either a boranophosphate or phosphorothioate moiety in the nucleoside neighbouring position(s) and some of them possess an additional methylene group between β and γ phosphorus atoms. The compounds were prepared by divalent metal chloride-mediated coupling of an appropriate m(7)GMP analogue with a given P(1),P(2)-di(1-imidazolyl) derivative. The analogues were evaluated as tools for studying cap-dependent processes in a number of biochemical assays, including determination of affinity to eukaryotic initiation factor eIF4E, susceptibility to enzymatic hydrolysis, and translational efficiency in vitro. The results indicate that modification in the phosphate chain can increase binding to cap-interacting proteins and provides higher resistance to degradation. Furthermore, modified derivatives of m(7)GTP were found to be potent inhibitors of cap-dependent translation in cell free systems.

  3. Nonlinear evolution of Airy-like beams generated by modulated waveguide arrays.

    PubMed

    Cao, Zheng; Tan, Qinggui; Li, Xiaojun; Qi, Xinyuan

    2016-08-20

    We numerically study the formation of modulated waveguide generated Airy-like beams and their subsequent evolution in homogeneous medium. The results show that the Airy-like beams could be generated from narrow Gaussian beams propagating in one-dimensional transverse separation modulated unbent, cosine bent, or logarithm bent waveguide arrays, respectively. The waveguide-generated Airy-like beams maintain their characteristics when propagating without nonlinearity or under the self-defocusing nonlinearity in homogeneous medium, while the beams are distorted under the self-focusing nonlinearity. The deformation depends on the waveguide bending and the outgoing angles of the Airy-like beams. Our results provide a new way to generate and manipulate the Airy-like beam.

  4. Multi-frequency phase-coded microwave signal generation based on polarization modulation and balanced detection.

    PubMed

    Zhu, Dan; Xu, Weiyuan; Wei, Zhengwu; Pan, Shilong

    2016-01-01

    Photonic multi-frequency phase-coded microwave signal generation is proposed and demonstrated based on polarization modulation and balanced detection. Consisting of only a polarization modulator (PolM) driven by an electrical coding data, a polarization beam splitter (PBS) and a balanced photodetector (BPD), the proposed microwave phase coder has no requirement on the wavelength, intensity modulation format, or modulation index of the input optical microwave signal, and allows phase coding of arbitrary-format RF signals, which enables multi-frequency phase coding with compact structure, simple operation, and high flexibility. A proof-of-concept experiment is performed, achieving simultaneous phase coding of 15 and 30 GHz, or 10 and 20 GHz RF signals with a coding rate of 5  Gb/s.

  5. Short optical pulse generation at 40 GHz with a bulk electro-absorption modulator packaged device

    NASA Astrophysics Data System (ADS)

    Langlois, Patrick; Moore, Ronald; Prosyk, Kelvin; O'Keefe, Sean; Oosterom, Jill A.; Betty, Ian; Foster, Robert; Greenspan, Jonathan; Singh, Priti

    2003-12-01

    Short optical pulse generation at 40GHz and 1540nm wavelength is achieved using fully packaged bulk quaternary electro-absorption modulator modules. Experimental results obtained with broadband and narrowband optimized packaged modules are presented and compared against empirical model predictions. Pulse duty cycle, extinction ratio and chirp are studied as a function of sinusoidal drive voltage and detuning between operating wavelength and modulator absorption band edge. Design rules and performance trade-offs are discussed. Low-chirp pulses with a FWHM of ~12ps and sub-4ps at a rate of 40GHz are demonstrated. Optical time-domain demultiplexing of a 40GHz to a 10GHz pulse train is also demonstrated with better than 20dB extinction ratio.

  6. Prefrontal cortex modulates desire and dread generated by nucleus accumbens glutamate disruption

    PubMed Central

    Richard, Jocelyn M.; Berridge, Kent. C

    2012-01-01

    Background Corticolimbic circuits, including direct projections from prefrontal cortex to nucleus accumbens (NAc), permit “top-down” control of intense motivations generated by subcortical circuits. In rats, localized disruptions of glutamate signaling within medial shell of NAc generate desire or dread, anatomically organized along a rostrocaudal gradient analogous to a limbic “keyboard”. At rostral locations in shell these disruptions generate appetitive eating, but at caudal locations the disruptions generate progressively fearful behaviors (distress vocalizations, escape attempts and antipredator reactions). Here we asked whether medial prefrontal cortex can modulate intense motivations generated by subcortical NAc disruptions. Methods We used simultaneous microinjections in medial prefrontal cortex regions and in NAc shell to examine whether the desire or dread generated by NAc shell disruptions is modulated by activation/inhibition of three specific regions of prefrontal cortex: medial orbitofrontal cortex, infralimbic cortex (homologous to area 25 or subgenual anterior cingulate in the human), or prelimbic cortex (midventral anterior cingulate). Results We found that activation of medial orbitofrontal cortex biased intense bivalent motivation in an appetitive direction by amplifying generation of eating behavior by middle to caudal NAc disruptions, without altering fear. In contrast, activation of infralimbic prefrontal cortex powerfully and generally suppressed both appetitive eating and fearful behaviors generated by NAc shell disruptions. Conclusions These results suggest that corticolimbic projections from discrete prefrontal regions can either bias motivational valence or generally suppress subcortically-generated intense motivations of desire or fear. PMID:22981656

  7. On-chip microwave signal generation based on a silicon microring modulator.

    PubMed

    Shao, Haifeng; Yu, Hui; Li, Xia; Li, Yan; Jiang, Jianfei; Wei, Huan; Wang, Gencheng; Dai, Tingge; Chen, Qimei; Yang, Jianyi; Jiang, Xiaoqing

    2015-07-15

    A photonic-assisted microwave signal generator based on a silicon microring modulator is demonstrated. The microring cavity incorporates an embedded PN junction that enables a microwave signal to modulate the lightwave circling inside. The DC component of the modulated light is trapped in the cavity, while the high-order sideband components are able to exit the cavity and then generate microwave signals at new frequencies in a photodetector. In our proof-of-concept experiment, a 10 GHz microwave signal is converted to a 20 GHz signal in the optical domain with an electrical harmonic suppression ratio of 22 dB. An analytic model is also established to explain the operation mechanism, which agrees well with the measured data.

  8. Generation of the "perfect" optical vortex using a liquid-crystal spatial light modulator.

    PubMed

    Ostrovsky, Andrey S; Rickenstorff-Parrao, Carolina; Arrizón, Víctor

    2013-02-15

    We introduce the concept of the perfect optical vortex whose dark hollow radius does not depend on the topological charge. It is shown analytically and experimentally that such a vortex can be approximately generated in the Fourier transforming optical system with a computer-controlled liquid-crystal spatial light modulator.

  9. Solid-state pulse modulator using Marx generator for a medical linac electron-gun

    NASA Astrophysics Data System (ADS)

    Lim, Heuijin; Hyeok Jeong, Dong; Lee, Manwoo; Lee, Mujin; Yi, Jungyu; Yang, Kwangmo; Ro, Sung Chae

    2016-04-01

    A medical linac is used for the cancer treatment and consists of an accelerating column, waveguide components, a magnetron, an electron-gun, a pulse modulator, and an irradiation system. The pulse modulator based on hydrogen thyratron-switched pulse-forming network is commonly used in linac. As the improvement of the high power semiconductors in switching speed, voltage rating, and current rating, an insulated gate bipolar transistor has become the more popular device used for pulsed power systems. We propose a solid-state pulse modulator to generator high voltage by multi-stacked storage-switch stages based on the Marx generator. The advantage of our modulator comes from the use of two semiconductors to control charging and discharging of the storage capacitor at each stage and it allows to generate the pulse with various amplitudes, widths, and shapes. In addition, a gate driver for two semiconductors is designed to reduce the control channels and to protect the circuits. It is developed for providing the pulsed power to a medical linac electron-gun that requires 25 kV and 1 A as the first application. In order to improve the power efficiency and achieve the compactness modulator, a capacitor charging power supply, a Marx pulse generator, and an electron-gun heater isolated transformer are constructed and integrated. This technology is also being developed to extend the high power pulsed system with > 1 MW and also other applications such as a plasma immersed ion implantation and a micro pulse electrostatic precipitator which especially require variable pulse shape and high repetition rate > 1 kHz. The paper describes the design features and the construction of this solid-state pulse modulator. Also shown are the performance results into the linac electron-gun.

  10. PDM-16QAM vector signal generation and detection based on intensity modulation and direct detection

    NASA Astrophysics Data System (ADS)

    Chen, Long; Yu, Jianjun; Li, Xinying

    2016-07-01

    We experimentally demonstrate a novel and simple method to generate and detect high speed polarization-division-multiplexing 16-ary quadrature-amplitude-modulation (PDM-16QAM) vector signal enabled by Mach-Zehnder modulator-based (MZM-based) optical-carrier-suppression (OCS) intensity modulation and direct detection. Due to the adoption of OCS intensity modulation, carrier beating can be avoided at the receiver, and thus polarization de-multiplexing can be implemented by digital-signal-processing-based (DSP-based) cascaded multi-modulus algorithm (CMMA) equalization instead of a polarization tracking system. The change of both amplitude and phase information due to the adoption of OCS modulation can be equalized by DSP-based amplitude and phase precoding at the transmitter. Up to 64-Gb/s PDM-16QAM vector signal is generated and detected after 2-km single-mode fiber-28 (SMF-28) or 20-km large-effective-area fiber (LEAF) transmission with a bit-error-ratio (BER) less than the hard-decision forward-error-correction (HD-FEC) threshold of 3.8×10-3.

  11. Photonic DPASK/QAM signal generation at microwave/millimeter-wave band based on an electro-optic phase modulator.

    PubMed

    Zhang, Ye; Xu, Kun; Zhu, Ran; Li, Jianqiang; Wu, Jian; Hong, Xiaobin; Lin, Jintong

    2008-10-15

    We have proposed and experimentally demonstrated two novel photonic architectures to generate differential-phase amplitude-shift keying and circular quadrature amplitude modulation signals at microwave/millimeter-wave band based on an electro-optic phase modulator. In our proposed schemes, the electronic driven circuits were greatly simplified by employing the photonic vector modulation technique.

  12. Steady dark solitary waves emerging from wave-generated meanflow: the role of modulation equations.

    PubMed

    Bridges, Thomas J

    2005-09-01

    Various classes of steady and unsteady dark solitary waves (DSWs) are known to exist in modulation equations for water waves in finite depth. However, there is a class of steady DSWS of the full water-wave problem which are missed by the classical modulation equations such as the Hasimoto-Ono, Benney-Roskes, and Davey-Stewartson. These steady DSWs, recently discovered by Bridges and Donaldson, are pervasive in finite depth, arise through secondary criticality of Stokes gravity waves, and are synchronized with the Stokes wave. In this paper, the role of DSWs in modulation equations for water waves is reappraised. The intrinsic unsteady nature of existing modulation equations filters out some interesting solutions. On the other hand, the geometry of DSWs in modulation equations is very similar to the full water wave problem and these geometrical properties are developed. A model equation is proposed which illustrates the general nature of the emergence of steady DSWs due to wave-generated mean flow coupled to a periodic wave. Although the existing modulation equations are intrinsically unsteady, it is shown that there are also important shortcomings when one wants to use them for stability analysis of DSWs.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Heterodimer Autorepression Loop: A Robust and Flexible Pulse-Generating Genetic Module

    NASA Astrophysics Data System (ADS)

    Lannoo, B.; Carlon, E.; Lefranc, M.

    2016-07-01

    We investigate the dynamics of the heterodimer autorepression loop (HAL), a small genetic module in which a protein A acts as an autorepressor and binds to a second protein B to form an A B dimer. For suitable values of the rate constants, the HAL produces pulses of A alternating with pulses of B . By means of analytical and numerical calculations, we show that the duration of A pulses is extremely robust against variation of the rate constants while the duration of the B pulses can be flexibly adjusted. The HAL is thus a minimal genetic module generating robust pulses with a tunable duration, an interesting property for cellular signaling.

  15. Generation of individually modulated femtosecond pulse string by multilayer volume holographic gratings.

    PubMed

    Yan, Xiaona; Gao, Lirun; Yang, Xihua; Dai, Ye; Chen, Yuanyuan; Ma, Guohong

    2014-10-20

    A scheme to generate individually modulated femtosecond pulse string by multilayer volume holographic grating (MVHG) is proposed. Based on Kogelnik's coupled-wave theory and matrix optics, temporal and spectral expressions of diffracted field are given when a femtosecond pulse is diffracted by a MVHG. It is shown that the number of diffracted sub-pulses in the pulse string equals to the number of grating layers of the MVHG, peak intensity and duration of each diffracted sub-pulse depend on thickness of the corresponding grating layer, whereas pulse interval between adjacent sub-pulses is related to thickness of the corresponding buffer layer. Thus by modulating parameters of the MVHG, individually modulated femtosecond pulse string can be acquired. Based on Bragg selectivity of the volume grating and phase shift provided by the buffer layers, we give an explanation on these phenomena. The result is useful to design MVHG-based devices employed in optical communications, pulse shaping and processing. PMID:25401645

  16. Generation of individually modulated femtosecond pulse string by multilayer volume holographic gratings.

    PubMed

    Yan, Xiaona; Gao, Lirun; Yang, Xihua; Dai, Ye; Chen, Yuanyuan; Ma, Guohong

    2014-10-20

    A scheme to generate individually modulated femtosecond pulse string by multilayer volume holographic grating (MVHG) is proposed. Based on Kogelnik's coupled-wave theory and matrix optics, temporal and spectral expressions of diffracted field are given when a femtosecond pulse is diffracted by a MVHG. It is shown that the number of diffracted sub-pulses in the pulse string equals to the number of grating layers of the MVHG, peak intensity and duration of each diffracted sub-pulse depend on thickness of the corresponding grating layer, whereas pulse interval between adjacent sub-pulses is related to thickness of the corresponding buffer layer. Thus by modulating parameters of the MVHG, individually modulated femtosecond pulse string can be acquired. Based on Bragg selectivity of the volume grating and phase shift provided by the buffer layers, we give an explanation on these phenomena. The result is useful to design MVHG-based devices employed in optical communications, pulse shaping and processing.

  17. Microwave Generation Based on Polarization Modulator and Brillouin-assisted Sideband-Filtering

    NASA Astrophysics Data System (ADS)

    Wei, Zhihu; Wang, Rong; Pu, Tao; Sun, Guodan; Fang, Tao; Xiong, Jintian

    2013-03-01

    A novel approach to generate continuously tunable microwave and millimeter-wave (mm-wave) signals is proposed and experimentally demonstrated. It is realized by a polarization modulator and a Brillouin-assisted sideband-filtering technique. The output optical signal of modulator is controlled to suppress the odd sidebands by a polarization controller and polarizer. After that, by adjusting the power of input microwave signal to remove the optical carrier, and then the strong second-order sideband of the modulated signal can be deeply suppressed by using stimulated Brillouin scattering (SBS) in a fiber ring while the fourth order sidebands keep unchanged. Therefore, only fourth-order sidebands signals exist at the input of the PD, frequency octupling can be realized. If the even sidebands are suppressed, the strong first order sidebands of the modulated signal will be deeply suppressed by the SBS filter, leaving the third sidebands, frequency sextupling can also be realized. As the SBS-assisted sideband-filter is narrow bandwidth and wavelength-independent, a wavelength-flexible way of optical generation mm-wave signals can be successfully realized.

  18. Design, fabrication, test, and qualification and price analysis of third generation design solar cell modules

    NASA Astrophysics Data System (ADS)

    Shepard, N. F.

    1980-03-01

    The Block 4 shingle type module makes it possible to apply a photovoltaic array to the sloping roof of a residential building by simply nailing the overlapping hexagon shaped shingles to the plywood roof sheathing. This third-generation shingle module design consists of nineteen series connected 100 mm diameter solar cells which are arranged in a closely packed hexagon configuration to provide in excess of 75 watts/sq m of exposed module area under standard operating conditions. The solar cells are individually bonded to the embossed underside of a 4.4 mm thick thermally tempered piece of glass. An experimental silicone pottant was used as the transparent bonding adhesive between the cells and glass. The semi-flexible portion of each shingle module is a composite laminate construction consisting of an outer layer of FLEXSEAL bonded to an inner core of closed cell polyethylene foam. Silaprene is used as the substrate laminating adhesive. The module design has satisfactorily survived qualification testing program which includes 50 thermal cycles between -40 and +90 C, a seven day temperature-humidity exposure test, and a wind resistance test.

  19. Design, fabrication, test, and qualification and price analysis of third generation design solar cell modules

    NASA Technical Reports Server (NTRS)

    Shepard, N. F.

    1980-01-01

    The Block 4 shingle type module makes it possible to apply a photovoltaic array to the sloping roof of a residential building by simply nailing the overlapping hexagon shaped shingles to the plywood roof sheathing. This third-generation shingle module design consists of nineteen series connected 100 mm diameter solar cells which are arranged in a closely packed hexagon configuration to provide in excess of 75 watts/sq m of exposed module area under standard operating conditions. The solar cells are individually bonded to the embossed underside of a 4.4 mm thick thermally tempered piece of glass. An experimental silicone pottant was used as the transparent bonding adhesive between the cells and glass. The semi-flexible portion of each shingle module is a composite laminate construction consisting of an outer layer of FLEXSEAL bonded to an inner core of closed cell polyethylene foam. Silaprene is used as the substrate laminating adhesive. The module design has satisfactorily survived qualification testing program which includes 50 thermal cycles between -40 and +90 C, a seven day temperature-humidity exposure test, and a wind resistance test.

  20. Three-Dimensional Finite-Element Simulation for a Thermoelectric Generator Module

    NASA Astrophysics Data System (ADS)

    Hu, Xiaokai; Takazawa, Hiroyuki; Nagase, Kazuo; Ohta, Michihiro; Yamamoto, Atsushi

    2015-10-01

    A three-dimensional closed-circuit numerical model of a thermoelectric generator (TEG) module has been constructed with COMSOL® Multiphysics to verify a module test system. The Seebeck, Peltier, and Thomson effects and Joule heating are included in the thermoelectric conversion model. The TEG model is employed to simulate the operation of a 16-leg TEG module based on bismuth telluride with temperature-dependent material properties. The module is mounted on a test platform, and simulated by combining the heat conduction process and thermoelectric conversion process. Simulation results are obtained for the terminal voltage, output power, heat flow, and efficiency as functions of the electric current; the results are compared with measurement data. The Joule and Thomson heats in all the thermoelectric legs, as functions of the electric current, are calculated by finite-element volume integration over the entire legs. The Peltier heat being pumped at the hot side and released at the cold side of the module are also presented in relation to the electric current. The energy balance relations between heat and electricity are verified to support the simulation.

  1. Chaos in coherence modulation: bifurcations of an oscillator generating optical delay fluctuations

    SciTech Connect

    Larger, Laurent; Lee, Min Won; Goedgebuer, Jean-Pierre; Elflein, Wilhelm; Erneux, Thomas

    2001-08-01

    A new chaos generator is described that produces chaotic fluctuations of the optical-path difference in a coherence modulator driven electrically by a nonlinear delayed-feedback loop. Numerical simulations and experimental results are reported. A closed branch of periodic solutions bounded by a forward and a reverse Hopf bifurcation is observed for the first time, to our knowledge, for this type of nonlinear dynamical system. {copyright} 2001 Optical Society of America

  2. Apparatus for Generating Thrust Using a Two Dimensional, Asymmetrical Capacitor Module

    NASA Technical Reports Server (NTRS)

    Campbell, Jonathan W. (Inventor)

    2002-01-01

    An asymmetrical capacitor module for generating thrust includes two conductive elements of similar but different geometries separated by a dielectric member. Improved embodiments provided in the construction of conductive elements of smaller axial extent include those where the element is formed by an annular wire or a dielectric supported ring. Other embodiments concern the dielectric member and involve changes in the extent and shape thereof.

  3. Millimeter-wave and microwave signal generation by low-bandwidth electro-optic phase modulation.

    PubMed

    Torres-Company, Víctor; Fernández-Alonso, Mercedes; Lancis, Jesús; Barreiro, Juan C; Andrés, Pedro

    2006-10-16

    We propose, analyze and numerically illustrate a photonic-based technique for waveform generation of electrical signals approaching the 50 GHz bandwidth with time apertures as large as a few nanoseconds, by low-frequency, up to 2 GHz, electro-optic phase modulation of time-stretched optical pulses. Synthesis of the electrical waveform relies on phase-to-amplitude conversion of the modulated signal by a group delay dispersion circuit designed to behave as a transversal filter with N taps. Although arbitrary waveform generation capabilities are limited, a wide variety of user-defined signals are numerically demonstrated by appropriately designing the low-frequency signal driving the electro-optical modulator. Frequency upshifting is controlled by the chirp of the stretched pulse which provides an additional degree of freedom. Finally, optical-to-electrical conversion allows for the user-defined electrical waveform. Simulations are given for square waveform generation demonstrating the high resolution and wide-band capabilities of the technique.

  4. Spectral modulation of third-harmonic generation by molecular alignment and preformed plasma

    NASA Astrophysics Data System (ADS)

    Li, Min; Li, An-Yuan; He, Bo-Qu; Yuan, Shuai; Zeng, He-Ping

    2016-08-01

    We demonstrate spectral modulation of third-harmonic generation from molecular alignment effects. The third harmonic spectrum is broadened or narrowed under different influences of cross-phase modulations originating from various molecular alignment revivals. Furthermore, the spectrum and spatial distribution of the generated third harmonic pulse change dramatically in the presence of a preformed plasma. Under the influence of a preformed plasma, a narrower third harmonic spectrum is observed, and the conical third-harmonic pulse increases while the axial part decreases. The investigation provides an effective method to modulate the spectral characteristic and spatial distribution of third-harmonic generation from intense femtosecond filament. Project supported by the National Key Scientific Instrument Project, China (Grant No. 2012YQ150092), the National Basic Research Program of China (Grant No. 2011CB808105), the National Natural Science Foundation of China (Grant No. 11434005), China Postdoctoral Science Foundation (Grant No. 2014M560348), the National Natural Science Foundation of China (Grant No. 11504237), and the Shanghai Municipal Science and Technology Commission, China (Grant No. 14JC1401600).

  5. Photonic ultra-wideband pulse generation, hybrid modulation and dispersion-compensation-free transmission in multi-access communication systems.

    PubMed

    Tan, Kang; Shao, Jing; Sun, Junqiang; Wang, Jian

    2012-01-16

    We propose and demonstrate a scheme for optical ultrawideband (UWB) pulse generation by exploiting a half-carrier-suppressed Mach-Zehnder modulator (MZM) and a delay-interferometer- and wavelength-division-multiplexer-based, reconfigurable and multi-channel differentiator (DWRMD). Multi-wavelength, polarity- and shape-switchable UWB pulses of monocycle, doublet, triplet, and quadruplet are experimentally generated simply by tuning two bias voltages to modify the carrier-suppression ratio of MZM and the differential order of DWRMD respectively. The pulse position modulation, pulse shape modulation, pulse amplitude modulation and binary phase-shift keying modulation of UWB pulses can also be conveniently realized with the same scheme structure, which indicates that the hybrid modulation of those four formats can be achieved. Consequently, the proposed approach has potential applications in multi-shape, multi-modulation and multi-access UWB-over-fiber communication systems.

  6. An Internet-based interactive module for air emissions from fossil fuel based power generation

    SciTech Connect

    Karman, D.; O`Leary, K.; O`Reilly, S. |

    1997-12-31

    The proliferation of the Internet, Web pages and associated software tools available for developing multimedia material provides significant opportunities in training, education and information transfer. This paper will describe the development, testing and evaluation of an interactive teaching module aimed at college and university students that have previous education in thermodynamics and basic chemistry. The module is currently in development at the Department of Civil and Environmental Engineering at Carleton University with support from Environment Canada. Preliminary testing of this module is expected to begin late January. The module contains options to look at CO, CO{sub 2}, SO{sub 2} and NO{sub x} emissions associated with electric power generation in thermal stations that use coal, natural gas, crude and distillate oil. Factors governing the thermal efficiency of typical boiler systems and the thermodynamic limitations for converting heat into work are discussed. Supporting background information such as emission trends and emission factors used in calculations are also included as part of this module. A simple Rankine cycle without reheat or regeneration is considered to compare the emissions per unit energy delivered from each of the fuels considered. For natural gas and distillate oil, combined cycle operation is considered with a gas turbine-heat recovery steam generator combination replacing the boiler in the simple Rankine cycle. For all fuels, the cogeneration option is investigated by expanding the steam to an intermediate pressure in the turbine and utilizing the remaining heat by condensing the steam in a heat recovery application. Emission factors and basic information on CO, SO{sub 2} and NO{sub x} control technologies are utilized to calculate and report the emissions per unit energy delivered under the various scenarios investigated.

  7. Multi-point laser spark generation for internal combustion engines using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Lyon, Elliott; Kuang, Zheng; Cheng, Hua; Page, Vincent; Shenton, Tom; Dearden, Geoff

    2014-11-01

    This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion - a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed.

  8. Synchronous-digitization for video rate polarization modulated beam scanning second harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

    Sullivan, Shane Z.; DeWalt, Emma L.; Schmitt, Paul D.; Muir, Ryan D.; Simpson, Garth J.

    2015-03-01

    Fast beam-scanning non-linear optical microscopy, coupled with fast (8 MHz) polarization modulation and analytical modeling have enabled simultaneous nonlinear optical Stokes ellipsometry (NOSE) and linear Stokes ellipsometry imaging at video rate (15 Hz). NOSE enables recovery of the complex-valued Jones tensor that describes the polarization-dependent observables, in contrast to polarimetry, in which the polarization stated of the exciting beam is recorded. Each data acquisition consists of 30 images (10 for each detector, with three detectors operating in parallel), each of which corresponds to polarization-dependent results. Processing of this image set by linear fitting contracts down each set of 10 images to a set of 5 parameters for each detector in second harmonic generation (SHG) and three parameters for the transmittance of the fundamental laser beam. Using these parameters, it is possible to recover the Jones tensor elements of the sample at video rate. Video rate imaging is enabled by performing synchronous digitization (SD), in which a PCIe digital oscilloscope card is synchronized to the laser (the laser is the master clock.) Fast polarization modulation was achieved by modulating an electro-optic modulator synchronously with the laser and digitizer, with a simple sine-wave at 1/10th the period of the laser, producing a repeating pattern of 10 polarization states. This approach was validated using Z-cut quartz, and NOSE microscopy was performed for micro-crystals of naproxen.

  9. Results of testing a development module of the second-generation E-Systems concentrating photovoltaic-thermal module

    SciTech Connect

    Harrison, T D

    1982-04-01

    An actively-cooled linear Fresnel lens concentrating photovoltaic and thermal module, designed and built by E-Systems, was tested in the Photovoltaic Advanced Systems Test Facility. Physical, electrical, and thermal characteristics of the module are presented. Module performance is characterized through the use of multiple linear regression techniques.

  10. Power Generation and Peltier Refrigeration by a Tubular π-Type Thermoelectric Module

    NASA Astrophysics Data System (ADS)

    Sakai, Akihiro; Kanno, Tsutomu; Takahashi, Kouhei; Tamaki, Hiromasa; Yamada, Yuka

    2015-11-01

    A tubular configuration is a practical form of thermoelectric (TE) device to generate electric power from fluid heat sources as well as to control the temperature of fluid media by Peltier effect. Here, we report the realization of a tubular π-type TE module which enables both power generation and Peltier refrigeration. The tubular module was obtained by stacking ring-shaped constituents in the axial direction, followed by simultaneous spark plasma sintering and joining processes. The experimentally-observed maximum power-density and efficiency are 0.9 kW/m2 and 2.2%, respectively, when a small temperature difference (Δ T) of 85 K was maintained using hot and cold water. Peltier refrigeration of the tube outer surface is also demonstrated. The obtained maximum Δ T and the cooling power density are Δ T = 49 K and 32.6 kW/m2, respectively. The present results indicate the high feasibility of this tube as a fluid-mediated practical TE module.

  11. Theta-Modulated Gamma-Band Synchronization Among Activated Regions During a Verb Generation Task

    PubMed Central

    Doesburg, Sam M.; Vinette, Sarah A.; Cheung, Michael J.; Pang, Elizabeth W.

    2012-01-01

    Expressive language is complex and involves processing within a distributed network of cortical regions. Functional MRI and magnetoencephalography (MEG) have identified brain areas critical for expressive language, but how these regions communicate across the network remains poorly understood. It is thought that synchronization of oscillations between neural populations, particularly at a gamma rate (>30 Hz), underlies functional integration within cortical networks. Modulation of gamma rhythms by theta-band oscillations (4–8 Hz) has been proposed as a mechanism for the integration of local cell coalitions into large-scale networks underlying cognition and perception. The present study tested the hypothesis that these oscillatory mechanisms of functional integration were present within the expressive language network. We recorded MEG while subjects performed a covert verb generation task. We localized activated cortical regions using beamformer analysis, calculated inter-regional phase locking between activated areas, and measured modulation of inter-regional gamma synchronization by theta phase. The results show task-dependent gamma-band synchronization among regions activated during the performance of the verb generation task, and we provide evidence that these transient and periodic instances of high-frequency connectivity were modulated by the phase of cortical theta oscillations. These findings suggest that oscillatory synchronization and cross-frequency interactions are mechanisms for functional integration among distributed brain areas supporting expressive language processing. PMID:22707946

  12. An automation of design and modelling tasks in NX Siemens environment with original software - generator module

    NASA Astrophysics Data System (ADS)

    Zbiciak, M.; Grabowik, C.; Janik, W.

    2015-11-01

    Nowadays the design constructional process is almost exclusively aided with CAD/CAE/CAM systems. It is evaluated that nearly 80% of design activities have a routine nature. These design routine tasks are highly susceptible to automation. Design automation is usually made with API tools which allow building original software responsible for adding different engineering activities. In this paper the original software worked out in order to automate engineering tasks at the stage of a product geometrical shape design is presented. The elaborated software works exclusively in NX Siemens CAD/CAM/CAE environment and was prepared in Microsoft Visual Studio with application of the .NET technology and NX SNAP library. The software functionality allows designing and modelling of spur and helicoidal involute gears. Moreover, it is possible to estimate relative manufacturing costs. With the Generator module it is possible to design and model both standard and non-standard gear wheels. The main advantage of the model generated in such a way is its better representation of an involute curve in comparison to those which are drawn in specialized standard CAD systems tools. It comes from fact that usually in CAD systems an involute curve is drawn by 3 points that respond to points located on the addendum circle, the reference diameter of a gear and the base circle respectively. In the Generator module the involute curve is drawn by 11 involute points which are located on and upper the base and the addendum circles therefore 3D gear wheels models are highly accurate. Application of the Generator module makes the modelling process very rapid so that the gear wheel modelling time is reduced to several seconds. During the conducted research the analysis of differences between standard 3 points and 11 points involutes was made. The results and conclusions drawn upon analysis are shown in details.

  13. Research of photonic-assisted triangular-shaped pulses generation based on quadrupling RF modulation

    NASA Astrophysics Data System (ADS)

    Yuan, Jin; Ning, Ti-gang; Li, Jing; Li, Yue-qin; Chen, Hong-yao; Zhang, Chan

    2015-05-01

    We propose an approach to generate optical triangular-shaped pulse train with tunable repetition rate using quadrupling radio frequency (RF) modulation and optical grating dispersion-induced power fading. In this work, a piece of chirped fiber Bragg grating (FBG) is employed as the dispersive media to remove the undesired 8th harmonic in optical intensity. Thus, the generated harmonics of optical intensity can be corresponding to the first two Fourier components of typical periodic triangular pulses. This work also analyzes the impacts of the extinction ratio and the bias voltage drift on the harmonic distortion suppression ratio. After that, the value of the extinction ratio and the range of the bias voltage drift can be obtained. The advantage of this proposal is that it can generate high order frequency-multiplexed optical pulses train which can be applied in all optical signal processing and other fields.

  14. Ultrafast laser parallel microdrilling using multiple annular beams generated by a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Kuang, Zheng; Perrie, Walter; Edwardson, Stuart P.; Fearon, Eamonn; Dearden, Geoff

    2014-03-01

    Ultrafast laser parallel microdrilling using diffractive multiple annular beam patterns is demonstrated in this paper. The annular beam was generated by diffractive axicon computer generated holograms (CGHs) using a spatial light modulator. The diameter of the annular beam can be easily adjusted by varying the radius of the smallest ring in the axicon. Multiple annular beams with arbitrary arrangement and multiple annular beam arrays were generated by superimposing an axicon CGH onto a grating and lenses algorithm calculated multi-beam CGH and a binary Dammann grating CGH, respectively. Microholes were drilled through a 0.03 mm thick stainless steel foil using the multiple annular beams. By avoiding huge laser output attenuation and mechanical annular scanning, the processing is ˜200 times faster than the normal single beam processing.

  15. Comparison of beam generation techniques using a phase only spatial light modulator.

    PubMed

    Clark, Thomas W; Offer, Rachel F; Franke-Arnold, Sonja; Arnold, Aidan S; Radwell, Neal

    2016-03-21

    Whether in art or for QR codes, images have proven to be both powerful and efficient carriers of information. Spatial light modulators allow an unprecedented level of control over the generation of optical fields by using digital holograms. There is no unique way of obtaining a desired light pattern however, leaving many competing methods for hologram generation. In this paper, we test six hologram generation techniques in the creation of a variety of modes as well as a photographic image: rating the methods according to obtained mode quality and power. All techniques compensate for a non-uniform mode profile of the input laser and incorporate amplitude scaling. We find that all methods perform well and stress the importance of appropriate spatial filtering. We expect these results to be of interest to those working in the contexts of microscopy, optical trapping or quantum image creation. PMID:27136818

  16. Integration of dye-sensitized solar cells, thermoelectric modules and electrical storage loop system to constitute a novel photothermoelectric generator.

    PubMed

    Chang, Ho; Yu, Zhi-Rong

    2012-08-01

    This study self-develops a novel type of photothermoelectric power generation modules. Dye-sensitized solar cells (DSSCs) serve as the photoelectric conversion system and a copper (Cu) heat-transfer nanofilm coating on both sides of the thermoelectric generator (TEG) acts as a thermoelectric conversion system. Thus module assembly absorbs light and generates electricity by DSSCs, and also recycles waste heat and generates power by the TEG. In addition, a set of pulsating heat pipes (PHP) filled with Cu nanofluid is placed on the cooling side to increase cooling effects and enhance the power generation efficiency. Results show that when the heat source of thermoelectric modules reaches 90 degrees C, TEG power output is increased by 85.7%. Besides, after thermoelectric modules are heated by additional heat source at 80 degrees C, the electrical energy generated by them can let a NiMH cell (1.25 V) be sufficiently charged in about 30 minutes. When photothermoelectric modules is illumined by simulated light, the temperature difference of two sides of TEG can reach 7 degrees C and the thermoelectric conversion efficiency is 2.17%. Furthermore, the power output of the thermoelectric modules is 11.48 mW/cm2, enhancing 1.4 % compared to merely using DSSCs module.

  17. Integration of dye-sensitized solar cells, thermoelectric modules and electrical storage loop system to constitute a novel photothermoelectric generator.

    PubMed

    Chang, Ho; Yu, Zhi-Rong

    2012-08-01

    This study self-develops a novel type of photothermoelectric power generation modules. Dye-sensitized solar cells (DSSCs) serve as the photoelectric conversion system and a copper (Cu) heat-transfer nanofilm coating on both sides of the thermoelectric generator (TEG) acts as a thermoelectric conversion system. Thus module assembly absorbs light and generates electricity by DSSCs, and also recycles waste heat and generates power by the TEG. In addition, a set of pulsating heat pipes (PHP) filled with Cu nanofluid is placed on the cooling side to increase cooling effects and enhance the power generation efficiency. Results show that when the heat source of thermoelectric modules reaches 90 degrees C, TEG power output is increased by 85.7%. Besides, after thermoelectric modules are heated by additional heat source at 80 degrees C, the electrical energy generated by them can let a NiMH cell (1.25 V) be sufficiently charged in about 30 minutes. When photothermoelectric modules is illumined by simulated light, the temperature difference of two sides of TEG can reach 7 degrees C and the thermoelectric conversion efficiency is 2.17%. Furthermore, the power output of the thermoelectric modules is 11.48 mW/cm2, enhancing 1.4 % compared to merely using DSSCs module. PMID:22962827

  18. Probing nuclear motion by frequency modulation of molecular high-order harmonic generation.

    PubMed

    Bian, Xue-Bin; Bandrauk, André D

    2014-11-01

    Molecular high-order harmonic generation (MHOHG) in a non-Born-Oppenheimer treatment of H(2)(+), D(2)(+), is investigated by numerical simulations of the corresponding time-dependent Schrödinger equations in full dimensions. As opposed to previous studies on amplitude modulation of intracycle dynamics in MHOHG, we demonstrate redshifts as frequency modulation (FM) of intercycle dynamics in MHOHG. The FM is induced by nuclear motion using intense laser pulses. Compared to fixed-nuclei approximations, the intensity of MHOHG is much higher due to the dependence of enhanced ionization on the internuclear distance. The width and symmetry of the spectrum of each harmonic in MHOHG encode rich information on the dissociation process of molecules at the rising and falling parts of the laser pulses, which can be used to retrieve the nuclear dynamics. Isotope effects are studied to confirm the FM mechanism.

  19. Fabrication and characterization of a microfluidic module for chemical gradient generation utilizing passive pumping.

    PubMed

    Kuo, Jonathan T W; Li, Connie; Meng, Ellis

    2014-01-01

    We introduce a micro-biochemical administration module (μBAM) for generating chemical gradients for use in axonal guidance studies. The device is designed to be simple to use, require minimal packaging, and be operated using only a pipette. A passive pumping mechanism is utilized to pump liquid through a SU-8 microchannel and then the micropore on the Parylene cap of the microchannel. The achievable flow rate delivery through the micropore was characterized and manipulated by varying the drop volumes used to passively drive fluid flow into the device. Biochemicals controllably delivered using this module can be combined with neuronal cell cultures to form chemical gradients for axonal guidance studies. PMID:25570971

  20. A megawatt solid-state modulator for high repetition rate pulse generation

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Pribyl, P.; Gekelman, W.

    2016-02-01

    A novel solid-state modulator capable of generating rapid consecutive power pulses is constructed to facilitate experiments on plasma interaction with high power microwave pulses. The modulator is designed to output a 100 kHz tone burst, which consists of up to 10 pulses, each with 1 μs duration and 1 MW peak power. The pulses are formed by discharging a total of 480 μF capacitors through 24 synchronized MOSFETs and 6 step-up transformers. The highly modular design, as a replacement of an old single-pulse version used in earlier experiments which employs a pulse forming network, brings great flexibility and wide potential to its application. A systematic cost-effectiveness analysis is also presented.

  1. A megawatt solid-state modulator for high repetition rate pulse generation.

    PubMed

    Wang, Y; Pribyl, P; Gekelman, W

    2016-02-01

    A novel solid-state modulator capable of generating rapid consecutive power pulses is constructed to facilitate experiments on plasma interaction with high power microwave pulses. The modulator is designed to output a 100 kHz tone burst, which consists of up to 10 pulses, each with 1 μs duration and 1 MW peak power. The pulses are formed by discharging a total of 480 μF capacitors through 24 synchronized MOSFETs and 6 step-up transformers. The highly modular design, as a replacement of an old single-pulse version used in earlier experiments which employs a pulse forming network, brings great flexibility and wide potential to its application. A systematic cost-effectiveness analysis is also presented. PMID:26931851

  2. Generation and propagation of a sine-azimuthal wavefront modulated Gaussian beam

    PubMed Central

    Lao, Guanming; Zhang, Zhaohui; Luo, Meilan; Zhao, Daomu

    2016-01-01

    We introduce a method for modulating the Gaussian beam by means of sine-azimuthal wavefront and carry out the experimental generation. The analytical propagation formula of such a beam passing through a paraxial ABCD optical system is derived, by which the intensity properties of the sine-azimuthal wavefront modulated Gaussian (SWMG) beam are examined both theoretically and experimentally. Both of the experimental and theoretical results show that the SWMG beam goes through the process from beam splitting to a Gaussian-like profile, which is closely determined by the phase factor and the propagation distance. Appropriate phase factor and short distance are helpful for the splitting of beam. However, in the cases of large phase factor and focal plane, the intensity distributions tend to take a Gaussian form. Such unique features may be of importance in particle trapping and medical applications. PMID:27443798

  3. A megawatt solid-state modulator for high repetition rate pulse generation.

    PubMed

    Wang, Y; Pribyl, P; Gekelman, W

    2016-02-01

    A novel solid-state modulator capable of generating rapid consecutive power pulses is constructed to facilitate experiments on plasma interaction with high power microwave pulses. The modulator is designed to output a 100 kHz tone burst, which consists of up to 10 pulses, each with 1 μs duration and 1 MW peak power. The pulses are formed by discharging a total of 480 μF capacitors through 24 synchronized MOSFETs and 6 step-up transformers. The highly modular design, as a replacement of an old single-pulse version used in earlier experiments which employs a pulse forming network, brings great flexibility and wide potential to its application. A systematic cost-effectiveness analysis is also presented.

  4. Generating Ultrashort Coherent Soft X-ray Radiation in Storage Rings Using Angular-modulated Electron Beams

    SciTech Connect

    Xiang, D.; Wan, W.; /LBL, Berkeley

    2010-08-23

    A technique is proposed to generate ultrashort coherent soft x-ray radiation in storage rings using angular-modulated electron beams. In the scheme a laser operating in the TEM01 mode is first used to modulate the angular distribution of the electron beam in an undulator. After passing through a special beam line with non-zero transfer matrix element R{sub 54}, the angular modulation is converted to density modulation which contains considerable higher harmonic contents of the laser. It is found that the harmonic number can be one or two orders of magnitude higher than the standard coherent harmonic generation method which relies on beam energy modulation. The technique has the potential of generating femtosecond coherent soft x-ray radiation directly from an infrared seed laser and may open new research opportunities for ultrafast sciences in storage rings.

  5. Fully Automated Volumetric Modulated Arc Therapy Plan Generation for Prostate Cancer Patients

    SciTech Connect

    Voet, Peter W.J. Dirkx, Maarten L.P.; Breedveld, Sebastiaan; Al-Mamgani, Abrahim; Incrocci, Luca; Heijmen, Ben J.M.

    2014-04-01

    Purpose: To develop and evaluate fully automated volumetric modulated arc therapy (VMAT) treatment planning for prostate cancer patients, avoiding manual trial-and-error tweaking of plan parameters by dosimetrists. Methods and Materials: A system was developed for fully automated generation of VMAT plans with our commercial clinical treatment planning system (TPS), linked to the in-house developed Erasmus-iCycle multicriterial optimizer for preoptimization. For 30 randomly selected patients, automatically generated VMAT plans (VMAT{sub auto}) were compared with VMAT plans generated manually by 1 expert dosimetrist in the absence of time pressure (VMAT{sub man}). For all treatment plans, planning target volume (PTV) coverage and sparing of organs-at-risk were quantified. Results: All generated plans were clinically acceptable and had similar PTV coverage (V{sub 95%} > 99%). For VMAT{sub auto} and VMAT{sub man} plans, the organ-at-risk sparing was similar as well, although only the former plans were generated without any planning workload. Conclusions: Fully automated generation of high-quality VMAT plans for prostate cancer patients is feasible and has recently been implemented in our clinic.

  6. Investigation on Nyquist pulse generation using a single dual-parallel Mach-Zehnder modulator.

    PubMed

    Wu, Jian; Zang, Jizhao; Li, Yan; Kong, Deming; Qiu, Jifang; Zhou, Siyuan; Shi, Jindan; Lin, Jintong

    2014-08-25

    The generation of Nyquist pulses with a dual parallel Mach-Zehnder modulator (DPMZM) driven by a single RF signal is demonstrated theoretically and experimentally. A complete theoretical analysis is developed and the limitation of the proposed scheme is also discussed. It is theoretically proved that Nyquist pulses with a spectrum of 5 flat comb lines can be generated using a single DPMZM, which is also verified with simulation. 7 flat comb lines in frequency domain can also be obtained if a large RF driving voltage is applied to DPMZM but the generated waveforms won't present a sinc-shape. This scheme is further investigated experimentally. 40 GHz Nyquist pulses with full-width-at-half-maximum (FWHM) less than 4.65 ps, signal-to-noise ratio (SNR) better than 29.5 dB, and normalized root-mean-square error (NRMSE) less than 2.4% are generated. It is found that a tradeoff exists between the insertion loss of the DPMZM and the deviation of generated pulses. The tunability of repetition rate is experimentally verified by generation of 1 GHz to 40 GHz Nyquist pulses with SNR better than 28.4 dB and NRMSE less than 6.15%.

  7. Multifunctional microstructured polymer films for boosting solar power generation of silicon-based photovoltaic modules.

    PubMed

    Leem, Jung Woo; Choi, Minkyu; Yu, Jae Su

    2015-02-01

    We propose two-dimensional periodic conical micrograting structured (MGS) polymer films as a multifunctional layer (i.e., light harvesting and self-cleaning) at the surface of outer polyethylene terephthalate (PET) cover-substrates for boosting the solar power generation in silicon (Si)-based photovoltaic (PV) modules. The surface of ultraviolet-curable NOA63 MGS polymer films fabricated by the soft imprint lithography exhibits a hydrophobic property with water contact angle of ∼121° at no inclination and dynamic advancing/receding water contact angles of ∼132°/111° at the inclination angle of 40°, respectively, which can remove dust particles or contaminants on the surface of PV modules in real outdoor environments (i.e., self-cleaning). The NOA63 MGS film coated on the bare PET leads to the reduction of reflection as well as the enhancement of both the total and diffuse transmissions at wavelengths of 300-1100 nm, indicating lower solar weighted reflectance (RSW) of ∼8.2%, higher solar weighted transmittance (TSW) of ∼93.1%, and considerably improved average haze ratio (HAvg) of ∼88.3% as compared to the bare PET (i.e., RSW ≈ 13.5%, TSW ≈ 86.9%, and HAvg ≈ 9.1%), respectively. Additionally, it shows a relatively good durability at temperatures of ≤160 °C. The resulting Si PV module with the NOA63 MGS/PET has an enhanced power conversion efficiency (PCE) of 13.26% (cf., PCE = 12.55% for the reference PV module with the bare PET) due to the mainly improved short circuit current from 49.35 to 52.01 mA, exhibiting the PCE increment percentage of ∼5.7%. For light incident angle-dependent PV module current-voltage characteristics, superior solar energy conversion properties are also obtained in a broad angle range of 10-80°.

  8. A Low-Cost Production Method of FeSi2 Power Generation Thermoelectric Modules

    NASA Astrophysics Data System (ADS)

    Inoue, Hiroyuki; Kobayashi, Takahide; Kato, Masahiko; Yoneda, Seiji

    2016-03-01

    A method is proposed to reduce the production cost of power generation thermoelectric modules. FeSi2 is employed as the thermoelectric material because of its low cost, low environmental load, and oxidation resistance. The raw materials were prepared in the composition of Fe0.96Si2.1Co0.04 for n-type and Fe0.92Si2.1Mn0.08 for p-type, which were added with 0.5 wt.% Cu as the starting materials. They were sintered without pressure at 1446 K to be formed into elements. The Seebeck coefficient and resistivity at room temperature were determined to be -182 μV/K and 0.13 mΩm for n-type, and 338 μV/K and 1.13 mΩm for p-type, respectively. The brazing conditions of the direct joining between the element and the solder were examined. Pastes of BNi-6, BNi-7 or TB-608T were tried as the solder. TB-608T was useable for metallizing of insulation substrates and joining of thermoelectric elements in order to manufacture thermoelectric modules. The joining strength was determined to be 50 MPa between the alumina plate and the elements. No mechanical failure was observed in the modules after repetition of 10 or more exposures to a heat source of 670 K. No change was found in the internal resistance. The present production method will provide modules with high durability and low production cost, which will enable high-power multi-stage cascade modules at a reasonable cost.

  9. Insulin stimulates the generation from hepatic plasma membranes of modulators derived from an inositol glycolipid.

    PubMed Central

    Saltiel, A R; Cuatrecasas, P

    1986-01-01

    Insulin binding to plasma membrane receptors results in the generation of substances that acutely mimic the actions of the hormone on certain target enzymes. Two such substances, which modulate the activity of the high-affinity cAMP phosphodiesterase (EC 3.1.4.17), have been purified from hepatic plasma membranes. The two have similar properties and activities but can be resolved by ion-exchange chromatography and high-voltage electrophoresis. They exhibit a net negative charge, even at pH 1.9, and an apparent molecular weight of approximately 1400. The generation of these substances from membranes by insulin can be reproduced by addition of a phosphatidylinositol-specific phospholipase C purified from Staphylococcus aureus. This enzyme is known to selectively hydrolyze phosphatidylinositol and release from membranes several proteins that are covalently linked to phosphatidylinositol by a glycan anchor. Both enzyme-modulating substances appear to be generated by the phosphodiesterase cleavage of a phosphatidylinositol-containing glycolipid precursor that has been characterized by thin-layer chromatography. Some of the chemical properties of these substances have been examined. They appear to be related complex carbohydrate-phosphate substances containing glucosamine and inositol. These findings suggest that insulin may activate a selective phospholipase activity that hydrolyzes a membrane phospholipid, releasing a carbohydrate-containing molecule that regulates cAMP phosphodiesterase and perhaps other insulin-sensitive enzymes. PMID:3016721

  10. Experimental study on trace chemical contaminant generation rates of human metabolism in spacecraft crew module

    NASA Astrophysics Data System (ADS)

    Lihua, Guo; Xinxing, He; Guoxin, Xu; Xin, Qi

    2012-12-01

    Trace chemical contaminants generated by human metabolism is a major source of contamination in spacecraft crew module. In this research, types and generation rates of pollutants from human metabolism were determined in the Chinese diets. Expired air, skin gas, and sweat of 20 subjects were analyzed at different exercise states in a simulated module. The exercise states were designed according to the basic activities in the orbit of astronauts. Qualitative and quantitative analyses of contaminants generated by human metabolic were performed with gas chromatography/mass spectrometry, gas chromatography and UV spectrophotometer. Sixteen chemical compounds from metabolic sources were found. With the increase in physical load, the concentrations of chemical compounds from human skin and expired air correspondingly increased. The species and the offgassing rates of pollutants from human metabolism are different among the Chinese, Americans and the Russians due to differences in ethnicity and dietary customs. This research provides data to aid in the design, development and operation of China's long duration space mission.

  11. Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System

    NASA Technical Reports Server (NTRS)

    Timmers, Richard B.; Hardy, Robin C.; Willey, Cliff E.; Welch, Joseph V.

    2009-01-01

    Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations, while meeting crew and vehicle safety requirements. The analyses and associated testing presented here surround a second generation of the airbag design developed by ILC Dover, building off of relevant first-generation design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley s Landing and Impact Research (LandIR) facility in Hampton, Virginia. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, develop the simulations, and make comparisons to experimental data are discussed.

  12. Olivocerebellar modulation of motor cortex ability to generate vibrissal movements in rat.

    PubMed

    Lang, Eric J; Sugihara, Izumi; Llinás, Rodolfo

    2006-02-15

    The vibrissal movements known as whisking are generated in a pulsatile, or non-continuous, fashion and comprise sequences of brief regularly spaced movements. These rhythmic timing sequences imply the existence of periodically issued motor commands. As inferior olivary (IO) neurones generate periodic synchronous discharges that could provide the underlying timing signal, this possibility was tested by determining whether the olivocerebellar system modulates motor cortex (MCtx)-triggered whisker movements in rats. Trains of current pulses were applied to MCtx, and the resulting whisker movements were recorded using a high speed video camera. The evoked movement patterns demonstrated properties consistent with the existence of an oscillatory motor driving rhythm. In particular, movement amplitude showed a bell-shaped dependence on stimulus frequency, with a peak at 11.5+/-2.3 Hz. Moreover, movement trajectories showed harmonic and subharmonic entrainment patterns within specific stimulus frequency ranges. By contrast, movements evoked by facial nerve stimulation showed no such frequency-dependent properties. To test whether the IO was the oscillator in question, IO neuronal properties were modified in vivo by intra-IO picrotoxin injection, which enhances synchronous oscillatory IO activity and reduces its natural frequency. The ensuing changes in the evoked whisker patterns were consistent with these pharmacological effects. Furthermore, in cerebellectomized rats, oscillatory modulation of MCtx-evoked movements was greatly reduced, and intra-IO picrotoxin injections did not affect the evoked movement patterns. Additionally, multielectrode recording of Purkinje cell complex spikes showed a temporal correlation of olivocerebellar activity during MCtx stimulus trains to evoked movement patterns. In sum, the results indicate that MCtx's ability to generate movements is modulated by an oscillatory signal arising in the olivocerebellar system. PMID:16357010

  13. Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals.

    PubMed

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

    2014-01-01

    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 central nervous system (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 electromyographic activity (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

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

    PubMed Central

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

    2015-01-01

    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 central nervous system (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 electromyographic activity (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

  15. Stable supercontinuum pulse generated by modulation instability in a dispersion-managed fiber

    NASA Astrophysics Data System (ADS)

    Duan, Liang; Yang, Zhan-Ying; Zhao, Li-Chen; Yang, Wen-Li

    2016-08-01

    We study on non-linear localized waves on continuous wave background in a dispersion and non-linearity management fibre. We find a stable supercontinuum pulse can be generated from a small modulation on continuous wave in a proper management way, for which the pulse spectrum width and its growth rate can be controlled well by the management parameters. Additionally, we demonstrate a Kuznetsov-Ma breather like non-linear localized wave can exist in a periodic dispersion management fibre, and its spectrum evolution is distinctive from the Kuznetsov-Ma breather's.

  16. Electromagnetic field generated by a modulated moving point source in a planarly layered waveguide

    NASA Astrophysics Data System (ADS)

    Barrera-Figueroa, V.; Rabinovich, V. S.

    2016-04-01

    In the present work, we consider a modulated point source in an arbitrary motion in an isotropic planarly layered waveguide. The radiation field generated by this source is represented in the form of double oscillatory integrals in terms of the time and the frequency, depending on the large parameter λ. By means of the stationary phase method, we analyze, in the waveguide, the Doppler effect, the retarded time, and the Vavilov-Cherenkov radiation. Numerically, the problem of the moving source is approached by the method of spectral parameter power series.

  17. Numerical generation of a polarization singularity array with modulated amplitude and phase.

    PubMed

    Ye, Dong; Peng, Xinyu; Zhao, Qi; Chen, Yanru

    2016-09-01

    A point having no defined polarized ellipse azimuthal angle (circularly polarized) in a space-variant vector field is called a polarization singularity, and it has three types: Lemon, Monstar, and Star. Recently, the connection of polarization singularities has been performed. Inspired by this, we conduct a numerical generation of a polarization singularity array. Our method is based on two orthogonal linearly polarized light beams with modulated amplitude and phase. With appropriate distribution functions of amplitudes and phases we can control the polarized states of polarization singularities, which offer a possibility to simulate a polarization singularity array. PMID:27607491

  18. Single-sideband W-band photonic vector millimeter-wave signal generation by one single I/Q modulator.

    PubMed

    Li, Xinying; Xu, Yuming; Yu, Jianjun

    2016-09-15

    We propose a new scheme to generate single-sideband (SSB) photonic vector millimeter-wave (mm-wave) signal adopting asymmetrical SSB modulation enabled by a single in-phase/quadrature (I/Q) modulator. The driving signal for the I/Q modulator is generated by software-based digital signal processing (DSP) instead of a complicated transmitter electrical circuit, which significantly simplifies the system architecture and increases system stability. One vector-modulated optical sideband and one unmodulated optical sideband, with different sideband frequencies, located at two sides of a significantly suppressed central optical carrier, are generated by the I/Q modulator and used for heterodyne beating to generate the electrical vector mm-wave signal. The two optical sidebands are robust to fiber dispersion and can be transmitted over relatively long-haul fiber. We experimentally demonstrate the generation and transmission of 4-Gbaud 80-GHz quadrature-phase-shift-keying-modulated (QPSK-modulated) SSB vector mm-wave signal over 240-km single-mode fiber-28 without optical dispersion compensation.

  19. Single-sideband W-band photonic vector millimeter-wave signal generation by one single I/Q modulator.

    PubMed

    Li, Xinying; Xu, Yuming; Yu, Jianjun

    2016-09-15

    We propose a new scheme to generate single-sideband (SSB) photonic vector millimeter-wave (mm-wave) signal adopting asymmetrical SSB modulation enabled by a single in-phase/quadrature (I/Q) modulator. The driving signal for the I/Q modulator is generated by software-based digital signal processing (DSP) instead of a complicated transmitter electrical circuit, which significantly simplifies the system architecture and increases system stability. One vector-modulated optical sideband and one unmodulated optical sideband, with different sideband frequencies, located at two sides of a significantly suppressed central optical carrier, are generated by the I/Q modulator and used for heterodyne beating to generate the electrical vector mm-wave signal. The two optical sidebands are robust to fiber dispersion and can be transmitted over relatively long-haul fiber. We experimentally demonstrate the generation and transmission of 4-Gbaud 80-GHz quadrature-phase-shift-keying-modulated (QPSK-modulated) SSB vector mm-wave signal over 240-km single-mode fiber-28 without optical dispersion compensation. PMID:27628347

  20. Investigation of torque generated by Test Blanket Module mock-up in DIII-D

    NASA Astrophysics Data System (ADS)

    Salmi, A.; Tala, T.; Lanctot, M.; Degrassie, J. S.; Paz-Soldan, C.; Logan, N.; Solomon, W. M.; Grierson, B. A.

    2015-11-01

    Experiments at DIII-D have investigated the scaling of Test Blanket Module (TBM) torque with plasma pressure and collisionality by performing dimensionless parameter scans. In each configuration, neutral beam torque modulation and TBM torque modulation were sequentially applied to allow experimental characterization of the TBM generated torque and the underlying transport. Calculations of the neoclassical toroidal viscosity (NTV) torque with PENT code of these plasmas find that TBM torque is strongly edge localized while the tentative experimental analysis indicates a more radially broad TBM torque profile. Both the experimental and PENT results will be elaborated and experimental TBM torque scaling with pressure and collisionality presented. Experimental validation of existing plasma response and NTV torque models is an important step toward understanding the impact of magnetic field ripple on plasma rotation, and for predicting the required compensation fields. Work supported by the US Department of Energy under DE-AC52-07NA27344, DE-FC02-04ER54698 and DE-AC02-09CH11466.

  1. Generation of controllabe and tighter multifocal array from the modulated azimuthally polarized beam

    PubMed Central

    MU, TINGKUI; CHEN, ZEYU; WU, RENGMAO; PACHECO, SHAUN; ZHANG, CHUNMIN; LIANG, RONGGUANG

    2016-01-01

    Comparisons of the focusing properties for the radially and azimuthally polarized beams with different pupil functions, such as uniform, Gaussian and Bessel-Gauss profiles, are presented. The results show that, for any pupil function, the spot sizes of the azimuthally polarized beam modulated with the vortex-0-2π-phase plate or the π-phase-step plate are smaller than that of the radially polarized beam encoded with or without these two types of plates. Then a type of multi-zone phase plate for generating tighter multifocal arrays from azimuthally polarized beams is proposed. The position and the linear polarization of the multifocal spots can be controlled by varying the pattern of the multi-zone phase plate and rotating the direction of the π-phase-step plate. In addition, for the radially polarized beam with Gaussian or Bessel-Gauss profiles and with the specified ratio of pupil diameter to beam diameter, the focal spot can be further reduced after modulated with the vortex-0-2π-phase plate, and the focal spot will be split into two after modulated with the π-phase-step plate. The latter property can be used to double the efficiency of parallel micro-manipulation. PMID:26766689

  2. Using Next Generation Science Standards to Strengthen Existing Climate Curriculum Modules

    NASA Astrophysics Data System (ADS)

    Haddad, N.; Ledley, T. S.; Ellins, K. K.; Bardar, E.; Dunlap, C.; Youngman, E.

    2013-12-01

    "Confronting the Challenges of Climate Literacy" is an NSF-funded (DRK-12) project that includes curriculum development, teacher professional development, teacher leadership development, and research on student learning, all directed at high school teachers and students. The curriculum unit includes three distinct but related modules: "Climate and the Cryosphere"; "Climate and the Biosphere"; and "Climate and the Carbon Cycle". These modules will be added to the growing EarthLabs collection. Climate related themes that cut across all three modules include the Earth system, with the complexities of its positive and negative feedback loops; the range of temporal and spatial scales at which climate, weather, and other Earth system processes occur; and the recurring question, 'How do we know what we know about Earth's past and present climate?' which addresses proxy data and scientific instrumentation. The project, launched in September 2010, used a backwards-design process that was keyed in large part to the 2009 version of 'Climate Literacy: The Essential Principles of Climate Science'. The first draft of the three curriculum modules was sent to partner teachers in June of 2011 for their review and feedback, and since then a round of pilot testing followed by a round of field testing has led to many revisions and refinements. By the time the final version of the Next Generation Science Standards (NGSS) was released in the spring of 2013, the modules were well along in their development. Nevertheless, with more than a year remaining in the project it was clear that explicitly addressing NGSS was an important next step. The challenge was, how do we approach this without starting over, without launching another 'backwards design' process keyed to the new standards? This presentation will share the different approaches we are using to address the three dimensions of NGSS in a substantive and meaningful way, without starting over, but through studying the various ways in

  3. Generation of optical and matter-wave solitons in binary systems with a periodically modulated coupling

    SciTech Connect

    Niederberger, Armand; Malomed, Boris A.; Lewenstein, Maciej

    2010-10-15

    We present a systematic study of the generation of the array of optical or matter-wave kinks (dark solitons) in the ground state (GS) of binary systems. We consider quasi-one-dimensional systems described by a pair of nonlinear Schroedinger (NLSE's) or Gross-Pitaevskii equations (GPE's), which are coupled by the linear mixing, with local strength {Omega}, and by nonlinear interactions. We assume the self-repulsive nonlinearity in both components, and include the effects of a harmonic trapping potential, while the nonlinear interaction between the components may be both repulsive and attractive. The model may be realized in terms of periodically modulated slab waveguides in nonlinear optics and also in Bose-Einstein condensates. Depending on the sign and strengths of the linear and nonlinear couplings between the components, the ground states in such binary systems may be symmetric, antisymmetric, or asymmetric. In this work, we introduce a periodic spatial modulation of the linear coupling, making {Omega} an odd or even function of the coordinate (x). The sign flips of {Omega}(x) strongly modify the structure of the GS in the binary system, as the relative sign of its components tends to lock to the local sign of {Omega}. Using a systematic numerical analysis and an analytic approximation, we demonstrate that the GS of the trapped system contains one or several kinks (dark solitons) in one component, while the other component does not change its sign. The final results are presented in the form of maps showing the number of kinks in the GS as a function of the system's parameters, with the odd (even) modulation function giving rise to the odd (even) number of the kinks. The modulation of {Omega}(x) also produces a strong effect on the transition between states with nearly equal and strongly unequal amplitudes of the two components.

  4. A Generic Biogeochemical Module for Earth System Models: Next Generation BioGeoChemical Module (NGBGC), Version 1.0

    SciTech Connect

    Fang, Yilin; Huang, Maoyi; Liu, Chongxuan; Li, Hongyi; Leung, Lai-Yung R.

    2013-11-13

    Physical and biogeochemical processes regulate soil carbon dynamics and CO2 flux to and from atmosphere, influencing global climate changes. Integration of these processes into earth system models (e.g., community land models (CLM)), however, currently faces three major challenges: 1) extensive efforts are required to modify modeling structures and to rewrite computer programs to incorporate new or updated processes as new knowledge is being generated, 2) computational cost is prohibitively expensive to simulate biogeochemical processes in land models due to large variations in the rates of biogeochemical processes, and 3) various mathematical representations of biogeochemical processes exist to incorporate different aspects of fundamental mechanisms, but systematic evaluation of the different mathematical representations is difficult, if not possible. To address these challenges, we propose a new computational framework to easily incorporate physical and biogeochemical processes into land models. The new framework consists of a new biogeochemical module with a generic algorithm and reaction database so that new and updated processes can be incorporated into land models without the need to manually set up the ordinary differential equations to be solved numerically. The reaction database consists of processes of nutrient flow through the terrestrial ecosystems in plants, litter and soil. This framework facilitates effective comparison studies of biogeochemical cycles in an ecosystem using different conceptual models under the same land modeling framework. The approach was first implemented in CLM and benchmarked against simulations from the original CLM-CN code. A case study was then provided to demonstrate the advantages of using the new approach to incorporate a phosphorus cycle into the CLM model. To our knowledge, the phosphorus-incorporated CLM is a new model that can be used to simulate phosphorus limitation on the productivity of terrestrial ecosystems.

  5. Optical frequency comb generation based on chirping of Mach-Zehnder Modulators

    NASA Astrophysics Data System (ADS)

    Hmood, Jassim K.; Emami, Siamak D.; Noordin, Kamarul A.; Ahmad, Harith; Harun, Sulaiman W.; Shalaby, Hossam M. H.

    2015-06-01

    A new approach for the generation of an optical frequency comb, based on chirping of modulators, is proposed and numerically demonstrated. The setup includes two cascaded Mach-Zehnder Modulators (MZMs), a sinusoidal wave oscillator, and an electrical time delay. The first MZM is driven directly by a sinusoidal wave, while the second MZM is driven by a delayed replica of the sinusoidal wave. A mathematical model of the proposed system is formulated and modeled using the Matlab software. It is shown that the number of the frequency lines is directly proportional to the chirp factor. In order to achieve the highest number of frequency comb lines with the best flatness, the time delay between the driving voltages of the two MZMs is optimized. Our results reveal that at least 51 frequency lines can be observed at the output spectrum. In addition, 27 of these lines have power fluctuations of less than 1 dB. The performance of the proposed system is also simulated using a split-step numerical analysis. An optical frequency comb, with tunable frequency spacing ranging from 5 to 40 GHz, is successfully generated.

  6. Comparison of cost- and energy-efficient signal modulations for next generation passive optical networks.

    PubMed

    Wei, J L; Grobe, K; Sanchez, C; Giacoumidis, E; Griesser, H

    2015-11-01

    Extensive numerical investigations are undertaken to analyze and compare, for the first time, the performance, techno-economy, and power consumption of three-level electrical Duobinary, optical Duobinary, and PAM-4 modulation formats as candidates for high-speed next-generation PONs supporting downstream 40 Gb/s per wavelength signal transmission over standard SMFs in C-band. Optimization of transceiver bandwidths are undertaken to show the feasibility of utilizing low-cost and band-limited components to support next-generation PON transmissions. The effect of electro-absorption modulator chirp is examined for electrical Duobinary and PAM-4. Electrical Duobinary and optical Duobinary are power-efficient schemes for smaller transmission distances of 10 km SMFs and optical Duobinary offers the best receiver sensitivity albeit with a relatively high transceiver cost. PAM-4 shows the best power budget and cost-efficiency for larger distances of around 20 km, although it consumes more power. Electrical Duobinary shows the best trade-off between performance, cost and power dissipation.

  7. Self-heterodyne interference spectroscopy using a comb generated by pseudo-random modulation.

    PubMed

    Hébert, Nicolas Bourbeau; Michaud-Belleau, Vincent; Anstie, James D; Deschênes, Jean-Daniel; Luiten, Andre N; Genest, Jérôme

    2015-10-19

    We present an original instrument designed to accomplish high-speed spectroscopy of individual optical lines based on a frequency comb generated by pseudo-random phase modulation of a continuous-wave (CW) laser. This approach delivers efficient usage of the laser power as well as independent control over the spectral point spacing, bandwidth and central wavelength of the comb. The comb is mixed with a local oscillator generated from the same CW laser frequency-shifted by an acousto-optic modulator, enabling a self-heterodyne detection scheme. The current configuration offers a calibrated spectrum every 1.12 µs. We demonstrate the capabilities of the spectrometer by producing averaged, as well as time-resolved, spectra of the D1 transition of cesium with a 9.8-MHz point spacing, a 50-kHz resolution and a span of more than 3 GHz. The spectra obtained after 1 ms of averaging are fitted with complex Voigt profiles that return parameters in good agreement with expected values. PMID:26480442

  8. Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System

    NASA Technical Reports Server (NTRS)

    Timmers, Richard B.; Welch, Joseph V.; Hardy, Robin C.

    2009-01-01

    Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). An important element of the air bag system design process is proper modeling of the proposed configuration to determine if the resulting performance meets requirements. Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations. The efforts presented here surround a second generation of the airbag design developed by ILC Dover, and is based on previous design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley's Landing and Impact Research (LandIR) facility. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, construct the simulations, and make comparisons to experimental data are discussed.

  9. Parallel generation of uniform fine droplets at hundreds of kilohertz in a flow-focusing module

    PubMed Central

    Bardin, David; Kendall, Michael R.; Dayton, Paul A.; Lee, Abraham P.

    2013-01-01

    Droplet-based microfluidic systems enable a variety of biomedical applications from point-of-care diagnostics with third world implications, to targeted therapeutics alongside medical ultrasound, to molecular screening and genetic testing. Though these systems maintain the key advantage of precise control of the size and composition of the droplet as compared to conventional methods of production, the low rates at which droplets are produced limits translation beyond the laboratory setting. As well, previous attempts to scale up shear-based microfluidic systems focused on increasing the volumetric throughput and formed large droplets, negating many practical applications of emulsions such as site-specific therapeutics. We present the operation of a parallel module with eight flow-focusing orifices in the dripping regime of droplet formation for the generation of uniform fine droplets at rates in the hundreds of kilohertz. Elevating the capillary number to access dripping, generation of monodisperse droplets of liquid perfluoropentane in the parallel module exceeded 3.69 × 105 droplets per second, or 1.33 × 109 droplets per hour, at a mean diameter of 9.8 μm. Our microfluidic method offers a novel means to amass uniform fine droplets in practical amounts, for instance, to satisfy clinical needs, with the potential for modification to form massive amounts of more complex droplets. PMID:24404032

  10. Modal Analysis and Study of the Vibration Characteristics of the Thermoelectric Modules of Vehicle Exhaust Power-Generation Systems

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Mu, Yu; Zhai, Pengcheng; Yu, Rui; Li, Guodong; Zhang, Qingjie

    2014-06-01

    Thermoelectric (TE) materials and modules are important components of vehicle exhaust power-generation systems. The road and the engine, the main sources of vibration of TE modules, have substantial effects on the vibration characteristics of TE modules. In this work, modal analysis and the vibration characteristics of TE modules were investigated in detail. On the basis of the TE modules and their service environment, simulations for modal analysis were performed by use of the finite-element method, and the natural frequencies and mode shapes of the TE modules were obtained. The numerical results were used to compare the natural frequencies of TE modules under different contact stiffness with the range of excitation frequencies of road and engine, in an attempt to prevent severe resonance. The effects on the vibration characteristics of geometric dimensions, service temperature, and thermal stress of the TE modules are also discussed in detail. The results reveal the vibration characteristics of the TE modules and provide theoretical guidance for structure optimization in the design of vehicle exhaust power-generation systems.

  11. Light Emitting Diode-Generated Blue Light Modulates Fibrosis Characteristics: Fibroblast Proliferation, Migration Speed, and Reactive Oxygen Species Generation

    PubMed Central

    Mamalis, Andrew; Garcha, Manveer; Jagdeo, Jared

    2016-01-01

    Background and Objective Blue light is part of the visible light spectrum that does not generate harmful DNA adducts associated with skin cancer and photoaging, and may represent a safer therapeutic modality for treatment of keloid scars and other fibrotic skin diseases. Our laboratory previously demonstrated that light-emitting diode (LED) red and infrared light inhibits proliferation of skin fibroblasts. Moreover, different wavelengths of light can produce different biological effects. Furthermore, the effects of LED blue light (LED-BL) on human skin fibroblasts are not well characterized. This study investigated the effects of LED-BL on human skin fibroblast proliferation, viability, migration speed, and reactive oxygen-species (ROS) generation. Methods and Materials Irradiation of adult human skin fibroblasts using commercially-available LED-BL panels was performed in vitro, and modulation of proliferation and viability was quantified using the trypan blue dye exclusion assay, migratory speed was assessed using time-lapse video microscopy, and intracellular ROS generation was measured using the dihydrorhodamine flow cytometry assay. Statistical differences between groups were determined by ANOVA and Student s t-test. Results Human skin fibroblasts treated with LED-BL fluences of 5, 30, 45, and 80 J/cm2 demonstrated statistically significant dose-dependent decreases in relative proliferation of 8.4%, 29.1%, 33.8%, 51.7%, and 55.1%, respectively, compared to temperature and environment matched bench control plates, respectively. LED-BL fluences of 5, 30, 45 and 80 J/cm2 decreased fibroblast migration speed to 95 ± 7.0% (p = 0.64), 81.3 ± 5.5% (p = 0.021), 48.5 ± 2.7% (p < 0.0001), and 32.3 ± 1.9% (p < 0.0001), respectively, relative to matched controls. LED fluences of 5, 10, 30, and 80 J/cm2 resulted in statistically significant increases in reactive oxygen species of 110.4%, 116.6%, 127.5%, and 130%, respectively, relative to bench controls. Conclusion At

  12. Generation of tunable, high repetition rate frequency combs with equalized spectra using carrier injection based silicon modulators

    NASA Astrophysics Data System (ADS)

    Nagarjun, K. P.; Selvaraja, Shankar Kumar; Supradeepa, V. R.

    2016-03-01

    High repetition-rate frequency combs with tunable repetition rate and carrier frequency are extensively used in areas like Optical communications, Microwave Photonics and Metrology. A common technique for their generation is strong phase modulation of a CW-laser. This is commonly implemented using Lithium-Niobate based modulators. With phase modulation alone, the combs have poor spectral flatness and significant number of missing lines. To overcome this, a complex cascade of multiple intensity and phase modulators are used. A comb generator on Silicon based on these principles is desirable to enable on-chip integration with other functionalities while reducing power consumption and footprint. In this work, we analyse frequency comb generation in carrier injection based Silicon modulators. We observe an interesting effect in these comb generators. Enhanced absorption accompanying carrier injection, an undesirable effect in data modulators, shapes the amplitude here to enable high quality combs from a single modulator. Thus, along with reduced power consumption to generate a specific number of lines, the complexity has also been significantly reduced. We use a drift-diffusion solver and mode solver (Silvaco TCAD) along with Soref-Bennett relations to calculate the variations in refractive indices and absorption of an optimized Silicon PIN - waveguide modulator driven by an unbiased high frequency (10 Ghz) voltage signal. Our simulations demonstrate that with a device length of 1 cm, a driving voltage of 2V and minor shaping with a passive ring-resonator filter, we obtain 37 lines with a flatness better than 5-dB across the band and power consumption an order of magnitude smaller than Lithium-Niobate modulators.

  13. Automatically-generated rectal dose constraints in intensity-modulated radiation therapy for prostate cancer

    NASA Astrophysics Data System (ADS)

    Hwang, Taejin; Kim, Yong Nam; Kim, Soo Kon; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk

    2015-06-01

    The dose constraint during prostate intensity-modulated radiation therapy (IMRT) optimization should be patient-specific for better rectum sparing. The aims of this study are to suggest a novel method for automatically generating a patient-specific dose constraint by using an experience-based dose volume histogram (DVH) of the rectum and to evaluate the potential of such a dose constraint qualitatively. The normal tissue complication probabilities (NTCPs) of the rectum with respect to V %ratio in our study were divided into three groups, where V %ratio was defined as the percent ratio of the rectal volume overlapping the planning target volume (PTV) to the rectal volume: (1) the rectal NTCPs in the previous study (clinical data), (2) those statistically generated by using the standard normal distribution (calculated data), and (3) those generated by combining the calculated data and the clinical data (mixed data). In the calculated data, a random number whose mean value was on the fitted curve described in the clinical data and whose standard deviation was 1% was generated by using the `randn' function in the MATLAB program and was used. For each group, we validated whether the probability density function (PDF) of the rectal NTCP could be automatically generated with the density estimation method by using a Gaussian kernel. The results revealed that the rectal NTCP probability increased in proportion to V %ratio , that the predictive rectal NTCP was patient-specific, and that the starting point of IMRT optimization for the given patient might be different. The PDF of the rectal NTCP was obtained automatically for each group except that the smoothness of the probability distribution increased with increasing number of data and with increasing window width. We showed that during the prostate IMRT optimization, the patient-specific dose constraints could be automatically generated and that our method could reduce the IMRT optimization time as well as maintain the

  14. Statement of Basis: Building M7-505 Treatment Tank SWMU 039

    NASA Technical Reports Server (NTRS)

    Starr, Andrew Scott

    2015-01-01

    The Statement of Basis (SB) has been developed to inform and give the public an opportunity to comment on a proposed remedy to address contamination at the Building M7-505 Treatment Tank (M7-505) site.

  15. Ytterbium-doped fiber ultrashort pulse generator based on self-phase modulation and alternating spectral filtering.

    PubMed

    Regelskis, Kęstutis; Želudevičius, Julijanas; Viskontas, Karolis; Račiukaitis, Gediminas

    2015-11-15

    We numerically and experimentally demonstrate a Yb-doped fiber ultrashort pulse generator based on self-phase modulation and alternating spectral filtering, operating at a wavelength of 1060 nm and providing a stable ultrashort pulse train. Pulses with energy up to 2.8 nJ were generated experimentally and were limited only by available pump power. PMID:26565848

  16. Generation and Dietary Modulation of Anti-Inflammatory Electrophilic Omega-3 Fatty Acid Derivatives

    PubMed Central

    Cipollina, Chiara; Salvatore, Sonia R.; Muldoon, Matthew F.; Freeman, Bruce A.; Schopfer, Francisco J.

    2014-01-01

    Dietary ω-3 polyunsaturated fatty acids (PUFAs) decrease cardiovascular risk via suppression of inflammation. The generation of electrophilic α,β-unsaturated ketone derivatives of the ω-3 PUFAs docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA) in activated human macrophages is catalyzed by cyclooxygenase-2 (Cox-2). These derivatives are potent pleiotropic anti-inflammatory signaling mediators that act via mechanisms including the activation of Nrf2-dependent phase 2 gene expression and suppression of pro-inflammatory NF-κB-driven gene expression. Herein, the endogenous generation of ω-3 PUFAs electrophilic ketone derivatives and their hydroxy precursors was evaluated in human neutrophils. In addition, their dietary modulation was assessed through a randomized clinical trial. Methods Endogenous generation of electrophilic omega-3 PUFAs and their hydroxy precursors was evaluated by mass spectrometry in neutrophils isolated from healthy subjects, both at baseline and upon stimulation with calcium ionophore. For the clinical trial, participants were healthy adults 30–55 years of age with a reported EPA+DHA consumption of ≤300 mg/day randomly assigned to parallel groups receiving daily oil capsule supplements for a period of 4 months containing either 1.4 g of EPA+DHA (active condition, n = 24) or identical appearing soybean oil (control condition, n = 21). Participants and laboratory technicians remained blinded to treatment assignments. Results 5-lypoxygenase-dependent endogenous generation of 7-oxo-DHA, 7-oxo-DPA and 5-oxo-EPA and their hydroxy precursors is reported in human neutrophils stimulated with calcium ionophore and phorbol 12-myristate 13-acetate (PMA). Dietary EPA+DHA supplementation significantly increased the formation of 7-oxo-DHA and 5-oxo-EPA, with no significant modulation of arachidonic acid (AA) metabolite levels. Conclusions The endogenous detection of these electrophilic ω-3 fatty acid ketone derivatives supports the

  17. Discovery of m7G-cap in eukaryotic mRNAs

    PubMed Central

    FURUICHI, Yasuhiro

    2015-01-01

    Terminal structure analysis of an insect cytoplasmic polyhedrosis virus (CPV) genome RNA in the early 1970s at the National Institute of Genetics in Japan yielded a 2′-O-methylated nucleotide in the 5′ end of double-stranded RNA genome. This finding prompted me to add S-adenosyl-L-methionine, a natural methylation donor, to the in vitro transcription reaction of viruses that contain RNA polymerase. This effort resulted in unprecedented mRNA synthesis that generates a unique blocked and methylated 5′ terminal structure (referred later to as “cap” or “m7G-cap”) in the transcription of silkworm CPV and human reovirus and vaccinia viruses that contain RNA polymerase in virus particles. Initial studies with viruses paved the way to discover the 5′-cap m7GpppNm structure present generally in cellular mRNAs of eukaryotes. I participated in those studies and was able to explain the pathway of cap synthesis and the significance of the 5′ cap (and capping) in gene expression processes, including transcription and protein synthesis. In this review article I concentrate on the description of these initial studies that eventually led us to a new paradigm of mRNA capping. PMID:26460318

  18. Fabrication of High-Temperature-Stable Thermoelectric Generator Modules Based on Nanocrystalline Silicon

    NASA Astrophysics Data System (ADS)

    Kessler, V.; Dehnen, M.; Chavez, R.; Engenhorst, M.; Stoetzel, J.; Petermann, N.; Hesse, K.; Huelser, T.; Spree, M.; Stiewe, C.; Ziolkowski, P.; Schierning, G.; Schmechel, R.

    2014-05-01

    High-temperature-stable thermoelectric generator modules (TGMs) based on nanocrystalline silicon have been fabricated, characterized by the Harman technique, and measured in a generator test facility at the German Aerospace Center. Starting with highly doped p- and n-type silicon nanoparticles from a scalable gas-phase process, nanocrystalline bulk silicon was obtained using a current-activated sintering technique. Electrochemical plating methods were employed to metalize the nanocrystalline silicon. The specific electrical contact resistance ρ c of the semiconductor-metal interface was characterized by a transfer length method. Values as low as ρ c < 1 × 10-6 Ω cm2 were measured. The device figure of merit of a TGM with 64 legs was approximately ZT = 0.13 at 600°C as measured by the Harman technique. Using a generator test facility, the maximum electrical power output of a TGM with 100 legs was measured to be roughly 1 W at hot-side temperature of 600°C and cold-side temperature of 300°C.

  19. Analysis of the Effect of Module Thickness Reduction on Thermoelectric Generator Output

    NASA Astrophysics Data System (ADS)

    Brito, F. P.; Figueiredo, L.; Rocha, L. A.; Cruz, A. P.; Goncalves, L. M.; Martins, J.; Hall, M. J.

    2016-03-01

    Conventional thermoelectric generators (TEGs) used in applications such as exhaust heat recovery are typically limited in terms of power density due to their low efficiency. Additionally, they are generally costly due to the bulk use of rare-earth elements such as tellurium. If less material could be used for the same output, then the power density and the overall cost per kilowatt (kW) of electricity produced could drop significantly, making TEGs a more attractive solution for energy harvesting of waste heat. The present work assesses the effect of reducing the amount of thermoelectric (TE) material used (namely by reducing the module thickness) on the electrical output of conventional bismuth telluride TEGs. Commercial simulation packages (ANSYS CFX and thermal-electric) and bespoke models were used to simulate the TEGs at various degrees of detail. Effects such as variation of the thermal and electrical contact resistance and the component thickness and the effect of using an element supporting matrix (e.g., eggcrate) instead of having air conduction in void areas have been assessed. It was found that indeed it is possible to reduce the use of bulk TE material while retaining power output levels equivalent to thicker modules. However, effects such as thermal contact resistance were found to become increasingly important as the active TE material thickness was decreased.

  20. Development of test particle module for impurity generation and transport in BOUT++ framework

    NASA Astrophysics Data System (ADS)

    Xiao, Xiaotao; Xu, Xueqiao

    2014-10-01

    Developing the test particle module in BOUT++ framework is the first step to enhance its capability to simulate impurity generation and transport in edge plasmas, which potentially can be extended to efficiently simulate both turbulence and neoclassical physics in realistic geometry. The motion of impurity charged particles are governed by guiding-center (GC) equations in the presence of turbulent electromagnetic fields. The GC equations are the well-known Hamiltonian guiding center equation given by Littlejohn, Boozer, White and others. The Fourth-order Runge-Kutta algorithm is used to advance the GC equations in time. In order easily to couple with BOUT++ fluid module, the same field aligned coordinates are used except near the region close to X-point. The bilinear interpolation is used to interpolate 3D fluid turbulent electromagnetic fields from grid points to particle positions. The calculated orbits in equilibrium configuration are checked to conserve constants of motion. The various guiding-center orbits in divertor configuration under BOUT++ framework are demonstrated and benchmarked. Then spatial distribution of impurities in edge plasmas from given sources at the divertor plates and at the protection limiters near RF antennas is obtained in given background plasma. This work was performed for USDOE by LLNL under DE-AC52-07NA27344, LLNL LDRD project 12-ERD-022 and the China Natural Science Foundation under Contract No. 11105185.

  1. Generation of nondiffracting quasi-circular polarization beams using an amplitude modulated phase hologram.

    PubMed

    Yuan, G H; Wei, S B; Yuan, X-C

    2011-08-01

    We propose an approach to the generation of nondiffracting quasi-circularly polarized beams by a highly focusing azimuthally polarized beam using an amplitude modulated spiral phase hologram. Numerical verifications are implemented in the calculation of the electromagnetic fields and Poynting vector field near the focus based on the vector diffraction theory, and the polarization of the wavefront near the focal plane is analyzed in detail by calculating the Stokes polarization parameters. It is found that the electric field, magnetic field, and Poynting vector field can simultaneously be uniform and nondiverging over a relatively long axial range of ~7.23λ. In the transverse plane, the ellipticity and azimuthal angle of the local polarization ellipse varies from point to point. No polarization singularity and phase singularity are found at the beam center, which makes the bright spot possible. PMID:21811334

  2. Biphoton Generation Driven by Spatial Light Modulation: Parallel-to-Series Conversion

    NASA Astrophysics Data System (ADS)

    Zhao, Luwei; Guo, Xianxin; Sun, Yuan; Su, Yumian; Loy, M. M. T.; Du, Shengwang

    2016-05-01

    We demonstrate the generation of narrowband biphotons with controllable temporal waveform by spontaneous four-wave mixing in cold atoms. In the group-delay regime, we study the dependence of the biphoton temporal waveform on the spatial profile of the pump laser beam. By using a spatial light modulator, we manipulate the spatial profile of the pump laser and map it onto the two-photon entangled temporal wave function. This parallel-to-series conversion (or spatial-to-temporal mapping) enables coding the parallel classical information of the pump spatial profile to the sequential temporal waveform of the biphoton quantum state. The work was supported by the Hong Kong RGC (Project No. 601113).

  3. Generation of an axially super-resolved quasi-spherical focal spot using an amplitude-modulated radially polarized beam.

    PubMed

    Lin, Han; Jia, Baohua; Gu, Min

    2011-07-01

    An axially super-resolved quasi-spherical focal spot can be generated by focusing an amplitude-modulated radially polarized beam through a high numerical aperture objective. A method based on the unique depolarization properties of a circular focus is proposed to design the amplitude modulation. The generated focal spot shows a ratio of x:y:z=1:1:1.48 for the normalized FWHM in three dimensions, compared to that of x:y:z=1:0.74:1.72 under linear polarization (in the x direction) illumination. Moreover, the focusable light efficiency of the designed amplitude-modulated beam is 65%, which is more than 3 times higher than the optimized case under linear polarization and thus make the amplitude-modulated radial polarization beam more suitable for a wide range of applications.

  4. Modulation instability and short-pulse generation in media with relaxing Kerr nonlinearity and high self-steepening

    SciTech Connect

    Zolotovskii, I O; Korobko, D A; Lapin, V A

    2014-01-31

    The modulation instability in waveguides with high Kerr nonlinearity, characterised by a delayed nonlinear response, has been investigated with allowance for the self-steepening parameter and third-order dispersion. General expressions for the modulation gain are obtained. The influence of the waveguide parameters on the gain is analysed. It is shown that the joint effect of the delayed nonlinear response and negative nonlinearity dispersion leads to an increase in the modulation gain. The relations obtained are confirmed by numerical simulation. The results of this study can be used to design compact generators of high-frequency pulse trains. (nonlinear optical phenomena)

  5. Dual-beam ELF wave generation as a function of power, frequency, modulation waveform, and receiver location

    NASA Astrophysics Data System (ADS)

    Agrawal, D.; Moore, R. C.

    2012-12-01

    Dual-beam ELF wave generation experiments performed at the High-frequency Active Auroral Research Program (HAARP) HF transmitter are used to investigate the dependence of the generated ELF wave magnitude on HF power, HF frequency, modulation waveform, and receiver location. During the experiments, two HF beams transmit simultaneously: one amplitude modulated (AM) HF beam modulates the conductivity of the lower ionosphere at ELF frequencies while a second HF beam broadcasts a continuous waveform (CW) signal, modifying the efficiency of ELF conductivity modulation and thereby the efficiency of ELF wave generation. We report experimental results for different ambient ionospheric conditions, and we interpret the observations in the context of a newly developed dual-beam HF heating model. A comparison between model predictions and experimental observations indicates that the theoretical model includes the essential physics involved in multifrequency HF heating of the lower ionosphere. In addition to the HF transmission parameters mentioned above, the model is used to predict the dependence of ELF wave magnitude on the polarization of the CW beam and on the modulation frequency of the modulated beam. We consider how these effects vary with ambientD-region electron density and electron temperature.

  6. Design, fabrication, test, qualification and price analysis of third generation design solar cell modules. Part 1: Intermediate load module

    NASA Technical Reports Server (NTRS)

    Bottenberg, W. R.

    1981-01-01

    The updated program plan and narrative reflects the design and development work done and progress made in establishing a viable design for these modules. Design alterations from the preproduction plan are discussed based on experience gained during the preproduction phase of the program.

  7. PHz-wide Supercontinua of Nondispersing Subcycle Pulses Generated by Extreme Modulational Instability

    NASA Astrophysics Data System (ADS)

    Tani, F.; Travers, J. C.; Russell, P. St. J.

    2013-07-01

    Modulational instability (MI) of 500 fs, 5μJ pulses, propagating in gas-filled hollow-core kagome photonic crystal fiber, is studied numerically and experimentally. By tuning the pressure and launched energy, we control the duration of the pulses emerging as a consequence of MI and hence are able to study two regimes: the classical MI case leading to few-cycle solitons of the nonlinear Schrödinger equation; and an extreme case leading to the formation of nondispersing subcycle pulses (0.5 to 2 fs) with peak intensities of order 1014Wcm-2. Insight into the two regimes is obtained using a novel statistical analysis of the soliton parameters. Numerical simulations and experimental measurements show that, when a train of these pulses is generated, strong ionization of the gas occurs. This extreme MI is used to experimentally generate a high energy (>1μJ) and spectrally broad supercontinuum extending from the deep ultraviolet (320 nm) to the infrared (1300 nm).

  8. PHz-wide supercontinua of nondispersing subcycle pulses generated by extreme modulational instability.

    PubMed

    Tani, F; Travers, J C; Russell, P St J

    2013-07-19

    Modulational instability (MI) of 500 fs, 5 μJ pulses, propagating in gas-filled hollow-core kagome photonic crystal fiber, is studied numerically and experimentally. By tuning the pressure and launched energy, we control the duration of the pulses emerging as a consequence of MI and hence are able to study two regimes: the classical MI case leading to few-cycle solitons of the nonlinear Schrödinger equation; and an extreme case leading to the formation of nondispersing subcycle pulses (0.5 to 2 fs) with peak intensities of order 10(14) W cm(-2). Insight into the two regimes is obtained using a novel statistical analysis of the soliton parameters. Numerical simulations and experimental measurements show that, when a train of these pulses is generated, strong ionization of the gas occurs. This extreme MI is used to experimentally generate a high energy (>1 μJ) and spectrally broad supercontinuum extending from the deep ultraviolet (320 nm) to the infrared (1300 nm).

  9. The Role of Gravity Waves in Generating Equatorial Oscillations in Modulating Atmospheric Tides

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Chan, K. L.; Porter, H. S.; Reddy, C. A.

    1999-01-01

    tide, the semidiurnal tide would also be modulated in this way. But the diurnal tide filters out the GW preferentially during equinox, so that the semidiurnal tide tends to peak during solstice. Under the influence of GW, the tides are modulated significantly by planetary waves that are generated preferentially during solstice in part due to baroclinic instability.

  10. Optimal synthesis of double-phase computer generated holograms using a phase-only spatial light modulator with grating filter.

    PubMed

    Song, Hoon; Sung, Geeyoung; Choi, Sujin; Won, Kanghee; Lee, Hong-Seok; Kim, Hwi

    2012-12-31

    We propose an optical system for synthesizing double-phase complex computer-generated holograms using a phase-only spatial light modulator and a phase grating filter. Two separated areas of the phase-only spatial light modulator are optically superposed by 4-f configuration with an optimally designed grating filter to synthesize arbitrary complex optical field distributions. The tolerances related to misalignment factors are analyzed, and the optimal synthesis method of double-phase computer-generated holograms is described. PMID:23388811

  11. Third generation focal plane array IR detection modules and applications (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Cabanski, W.; Munzberg, M.; Rode, W.; Wendler, J.; Ziegler, J.; Fleissner, J.; Fuchs, F.; Rehm, R.; Schmitz, J.; Schneider, H.; Walther, M.

    2005-05-01

    The 3rd generation of infrared (IR) detection modules is expected to provide advanced features like higher resolution 1024x1024 or 1280x720 pixels and/or new functions like multicolor or multi band capability, higher frame rates and better thermal resolution. This paper is intended to present the current status at AIM on quantum well (QWIP) and antimonide superlattices (SL) detection modules for ground and airborne applications in the high performance range. For spectral selective detection, a QWIP detector combining 3-5μm (MWIR) and 8-10μm (LWIR) detection in each pixel with coincident integration has been developed in a 384x288x2 format with 40 μm pitch. Excellent thermal resolution with NETD < 30mK @ F/2, 6.8 ms for both peak wavelengths (4.8 μm and 8.0 μm) has been achieved. Thanks to the well established QWIP technology, the pixel outage rates even in these complex structures are below 0.5% in both bands. QWIP dual band or dual color detectors provide good resolution as long as integration times in the order of 5-10ms can be tolerated. This is acceptable for all applications where no fast motions of the platform or the targets are to be expected. For rapidly changing scenes-like e.g. in case of missile warning applications for airborne platforms-a material system with higher quantum efficiency is required to limit integration times to typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The SL technology provides-similar to QWIP's-an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. While promising results on single SL pixels have been reported since many years, so far no SL based detection module could be realized. IAF and AIM last year managed to realize first most promising SL based detectors. Fully integrated IDCA's with a MWIR SL device with 256x256 pixels in 40μm pitch have been integrated and tested. The modules exhibit excellent thermal resolution of

  12. W-band RoF transmission based on optical multi-carrier generation by cascading one directly-modulated DFB laser and one phase modulator

    NASA Astrophysics Data System (ADS)

    Li, Xinying; Yu, Jianjun

    2015-06-01

    We experimentally demonstrate that, adopting an optical multi-carrier source based on cascaded directly-modulated distributed-feedback laser (DML) and phase modulator (PM), any pair of subcarriers spaced by 100 GHz selected from the generated optical subcarriers can be used to generate 100-GHz millimeter-wave (mm-wave) frequency based on remote heterodyning technique, and thus realize 3.125-Gb/s on-off-keying (OOK) signal transmission over a radio-over-fiber (RoF) system at W-band. After 20-km large-effective-area fiber (LEAF) transmission and 2-m wireless delivery, the bit-error ratio (BER) of 1×10-9 can be attained when the two selected subcarriers spaced by 100 GHz are simultaneously modulated before remote heterodyning. 1.5-dB power penalty at the BER of 1×10-9 is caused by 2-m wireless delivery while almost no penalty is caused by 20-km LEAF transmission. However, because of different path lengths and the quite wide linewidth of the DML, the 3.125-Gb/s OOK signal after the same RoF transmission cannot be recovered when the two selected subcarriers are separated into two different optical paths and only one of them is modulated before remote heterodyning.

  13. Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network.

    PubMed

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana M; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

    2014-01-01

    In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions.

  14. Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network.

    PubMed

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana M; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

    2014-01-01

    In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions

  15. Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network

    PubMed Central

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana M.; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

    2014-01-01

    In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions

  16. 25 Gbit/s differential phase-shift-keying signal generation using directly modulated quantum-dot semiconductor optical amplifiers

    SciTech Connect

    Zeghuzi, A. Schmeckebier, H.; Stubenrauch, M.; Bimberg, D.; Meuer, C.; Schubert, C.; Bunge, C.-A.

    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.

  17. Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy.

    PubMed

    Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

    2016-01-01

    The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process. PMID:27596718

  18. Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy.

    PubMed

    Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

    2016-09-06

    The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process.

  19. Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy

    NASA Astrophysics Data System (ADS)

    Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

    2016-09-01

    The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process.

  20. Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy

    PubMed Central

    Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

    2016-01-01

    The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process. PMID:27596718

  1. New generation polyphase resonant converter-modulators for the Korean atomic energy research institute

    SciTech Connect

    Reass, William A; Baca, David M; Gribble, Robert F

    2009-01-01

    This paper will present operational data and performance parameters of the newest generation polyphase resonant high voltage converter modulator (HVCM) as developed and delivered to the KAERI 100 MeV ''PEFP'' accelerator [1]. The KAERI design realizes improvements from the SNS and SLAC designs [2]. To improve the IGBT switching performance at 20 kHz for the KAERI system, the HVCM utilizes the typical zero-voltage-switching (ZVS) at turn on and as well as artificial zero-current-switching (ZCS) at turn-off. The new technique of artificial ZCS technique should result in a 6 fold reduction of IGBT switching losses (3). This improves the HCVM conversion efficiency to better than 95% at full average power, which is 500 kW for the KAERI two klystron 105 kV, 50 A application. The artificial ZCS is accomplished by placing a resonant RLC circuit across the input busswork to the resonant boost transformer. This secondary resonant circuit provides a damped ''kick-back'' to assist in IGBT commutation. As the transformer input busswork is extremely low inductance (< 10 nH), the single RLC network acts like it is across each of the four IGBT collector-emitter terminals of the H-bridge switching network. We will review these topological improvements and the overall system as delivered to the KAERI accelerator and provide details of the operational results.

  2. Polarization-modulated second harmonic generation ellipsometric microscopy at video rate.

    PubMed

    DeWalt, Emma L; Sullivan, Shane Z; Schmitt, Paul D; Muir, Ryan D; Simpson, Garth J

    2014-08-19

    Fast 8 MHz polarization modulation coupled with analytical modeling, fast beam-scanning, and synchronous digitization (SD) have enabled simultaneous nonlinear optical Stokes ellipsometry (NOSE) and polarized laser transmittance imaging with image acquisition rates up to video rate. In contrast to polarimetry, in which the polarization state of the exiting beam is recorded, NOSE enables recovery of the complex-valued Jones tensor of the sample that describes all polarization-dependent observables of the measurement. Every video-rate scan produces a set of 30 images (10 for each detector with three detectors operating in parallel), each of which corresponds to a different polarization-dependent result. Linear fitting of this image set contracts it down to a set of five parameters for each detector in second harmonic generation (SHG) and three parameters for the transmittance of the incident beam. These parameters can in turn be used to recover the Jones tensor elements of the sample. Following validation of the approach using z-cut quartz, NOSE microscopy was performed for microcrystals of both naproxen and glucose isomerase. When weighted by the measurement time, NOSE microscopy was found to provide a substantial (>7 decades) improvement in the signal-to-noise ratio relative to our previous measurements based on the rotation of optical elements and a 3-fold improvement relative to previous single-point NOSE approaches. PMID:25050448

  3. Polarization-Modulated Second Harmonic Generation Ellipsometric Microscopy at Video Rate

    PubMed Central

    2015-01-01

    Fast 8 MHz polarization modulation coupled with analytical modeling, fast beam-scanning, and synchronous digitization (SD) have enabled simultaneous nonlinear optical Stokes ellipsometry (NOSE) and polarized laser transmittance imaging with image acquisition rates up to video rate. In contrast to polarimetry, in which the polarization state of the exiting beam is recorded, NOSE enables recovery of the complex-valued Jones tensor of the sample that describes all polarization-dependent observables of the measurement. Every video-rate scan produces a set of 30 images (10 for each detector with three detectors operating in parallel), each of which corresponds to a different polarization-dependent result. Linear fitting of this image set contracts it down to a set of five parameters for each detector in second harmonic generation (SHG) and three parameters for the transmittance of the incident beam. These parameters can in turn be used to recover the Jones tensor elements of the sample. Following validation of the approach using z-cut quartz, NOSE microscopy was performed for microcrystals of both naproxen and glucose isomerase. When weighted by the measurement time, NOSE microscopy was found to provide a substantial (>7 decades) improvement in the signal-to-noise ratio relative to our previous measurements based on the rotation of optical elements and a 3-fold improvement relative to previous single-point NOSE approaches. PMID:25050448

  4. Automatic generation of modules of object categorization for autonomous mobile robots

    NASA Astrophysics Data System (ADS)

    Gorbenko, Anna

    2013-10-01

    Many robotic tasks require advanced systems of visual sensing. Robotic systems of visual sensing must be able to solve a number of different complex problems of visual data analysis. Object categorization is one of such problems. In this paper, we propose an approach to automatic generation of computationally effective modules of object categorization for autonomous mobile robots. This approach is based on the consideration of the stack cover problem. In particular, it is assumed that the robot is able to perform an initial inspection of the environment. After such inspection, the robot needs to solve the stack cover problem by using a supercomputer. A solution of the stack cover problem allows the robot to obtain a template for computationally effective scheduling of object categorization. Also, we consider an efficient approach to solve the stack cover problem. In particular, we consider an explicit reduction from the decision version of the stack cover problem to the satisfiability problem. For different satisfiability algorithms, the results of computational experiments are presented.

  5. Genetic and Epigenetic Modulation of Growth Hormone Sensitivity Studied With the IGF-1 Generation Test

    PubMed Central

    Ouni, Meriem; Castell, Anne-Laure; Linglart, Agnès

    2015-01-01

    Context: Like all hormones, GH has variable physiological effects across people. Many of these effects initiated by the binding of GH to its receptor (GHR) in target tissues are mediated by the expression of the IGF1 gene. Genetic as well as epigenetic variation is known to contribute to the individual diversity of GH-dependent phenotypes through two mechanisms. The first one is the genetic polymorphism of the GHR gene due to the common deletion of exon 3. The second, more recently reported, is the epigenetic variation in the methylation of a cluster of CGs dinucleotides located within the proximal part of the P2 promoter of the IGF-1 (IGF1) gene, notably CG-137. Objective: The current study evaluates the relative contribution of these two factors controlling individual GH sensitivity by measuring the response of serum IGF-1 to a GH injection (IGF-1 generation test) in a sample of 72 children with idiopathic short stature. Results: Although the d3 polymorphism of the GHR contributed 19% to the variance of the IGF-1 response, CG-137 methylation in the IGF-1 promoter contributed 30%, the combined contribution of the two factors totaling 43%. Conclusion: Our observation indicates that genetic and epigenetic variation at the GHR and IGF-1 loci play a major role as independent modulators of individual GH sensitivity. PMID:25835289

  6. Generation of a super-Rayleigh speckle field via a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Li, Xinzhong; Tai, Yuping; Li, Hehe; Wang, Jingge; Wang, Hui; Nie, Zhaogang

    2016-04-01

    This study investigated the generation method and properties of a super-Rayleigh speckle field that had a contrast value greater than 1. First, an exponential factor was added to the complex amplitude of the Rayleigh speckle, and then, its inverse Fourier-transformed phase matrix was applied to a spatial light modulator (SLM). As the collimated light beam illuminated the SLM, the super-Rayleigh speckle field was formed at the SLM's Fourier plane. The effects of the exponential factor, size of the macro-pixel of the SLM, and diameter of the entrance pupil on the contrast values of the super-Rayleigh speckle patterns were investigated. Especially, the influence of different macro-pixel sizes of the SLM was systematically studied. Moreover, the stability region of the super-Rayleigh speckle field was examined. The experimental results showed that the contrast values of the super-Rayleigh speckle field increased exponentially as the exponential factor increased under the same conditions. In addition, the contrast values increased as the size of the macro-pixel or diameter of the entrance pupil increased. Furthermore, as the pupil diameter increased, the width of the stability region decreased according to a negative quadratic index that corresponded to the longitudinal length of a single speckle.

  7. Measuring Selective Estrogen Receptor Modulator (SERM)–Membrane Interactions with Second Harmonic Generation

    PubMed Central

    2015-01-01

    The interaction of selective estrogen receptor modulators (SERMs) with lipid membranes has been measured at clinically relevant serum concentrations using the label-free technique of second harmonic generation (SHG). The SERMs investigated in this study include raloxifene, tamoxifen, and the tamoxifen metabolites 4-hydroxytamoxifen, N-desmethyltamoxifen, and endoxifen. Equilibrium association constants (Ka) were measured for SERMs using varying lipid compositions to examine how lipid phase, packing density, and cholesterol content impact SERM-membrane interactions. Membrane-binding properties of tamoxifen and its metabolites were compared on the basis of hydroxyl group substitution and amine ionization to elucidate how the degree of drug ionization impacts membrane partitioning. SERM-membrane interactions were probed under multiple pH conditions, and drug adsorption was observed to vary with the concentration of soluble neutral species. The agreement between Ka values derived from SHG measurements of the interactions between SERMs and artificial cell membranes and independent observations of the SERMs efficacy from clinical studies suggests that quantifying membrane adsorption properties may be important for understanding SERM action in vivo. PMID:24410282

  8. Modulation of Na+/K+ ATPase Activity by Hydrogen Peroxide Generated through Heme in L. amazonensis.

    PubMed

    Rocco-Machado, Nathália; Cosentino-Gomes, Daniela; Meyer-Fernandes, José Roberto

    2015-01-01

    Leishmania amazonensis is a protozoan parasite that occurs in many areas of Brazil and causes skin lesions. Using this parasite, our group showed the activation of Na+/K+ ATPase through a signaling cascade that involves the presence of heme and protein kinase C (PKC) activity. Heme is an important biomolecule that has pro-oxidant activity and signaling capacity. Reactive oxygen species (ROS) can act as second messengers, which are required in various signaling cascades. Our goal in this work is to investigate the role of hydrogen peroxide (H2O2) generated in the presence of heme in the Na+/K+ ATPase activity of L. amazonensis. Our results show that increasing concentrations of heme stimulates the production of H2O2 in a dose-dependent manner until a concentration of 2.5 μM heme. To confirm that the effect of heme on the Na+/K+ ATPase is through the generation of H2O2, we measured enzyme activity using increasing concentrations of H2O2 and, as expected, the activity increased in a dose-dependent manner until a concentration of 0.1 μM H2O2. To investigate the role of PKC in this signaling pathway, we observed the production of H2O2 in the presence of its activator phorbol 12-myristate 13-acetate (PMA) and its inhibitor calphostin C. Both showed no effect on the generation of H2O2. Furthermore, we found that PKC activity is increased in the presence of H2O2, and that in the presence of calphostin C, H2O2 is unable to activate the Na+/K+ ATPase. 100 μM of Mito-TEMPO was capable of abolishing the stimulatory effect of heme on Na+/K+ ATPase activity, indicating that mitochondria might be the source of the hydrogen peroxide production induced by heme. The modulation of L. amazonensis Na+/K+ ATPase by H2O2 opens new possibilities for understanding the signaling pathways of this parasite. PMID:26070143

  9. Silicon photonic Mach Zehnder modulators for next-generation short-reach optical communication networks

    NASA Astrophysics Data System (ADS)

    Lacava, C.; Liu, Z.; Thomson, D.; Ke, Li; Fedeli, J. M.; Richardson, D. J.; Reed, G. T.; Petropoulos, P.

    2016-02-01

    Communication traffic grows relentlessly in today's networks, and with ever more machines connected to the network, this trend is set to continue for the foreseeable future. It is widely accepted that increasingly faster communications are required at the point of the end users, and consequently optical transmission plays a progressively greater role even in short- and medium-reach networks. Silicon photonic technologies are becoming increasingly attractive for such networks, due to their potential for low cost, energetically efficient, high-speed optical components. A representative example is the silicon-based optical modulator, which has been actively studied. Researchers have demonstrated silicon modulators in different types of structures, such as ring resonators or slow light based devices. These approaches have shown remarkably good performance in terms of modulation efficiency, however their operation could be severely affected by temperature drifts or fabrication errors. Mach-Zehnder modulators (MZM), on the other hand, show good performance and resilience to different environmental conditions. In this paper we present a CMOS-compatible compact silicon MZM. We study the application of the modulator to short-reach interconnects by realizing data modulation using some relevant advanced modulation formats, such as 4-level Pulse Amplitude Modulation (PAM-4) and Discrete Multi-Tone (DMT) modulation and compare the performance of the different systems in transmission.

  10. Generation of a frequency sextupled optical millimeter wave with a suppressed central carrier using one single-electrode modulator

    NASA Astrophysics Data System (ADS)

    Lu, Jia; Dong, Ze; Liu, Jianfei; Zeng, Xiangye; Hu, Yuanyuan; Gao, Junping

    2014-10-01

    We have theoretically and experimentally investigated the generation of optical millimeter wave (mm-wave) generation based on a quadrupling and sextupling technique using one single-electrode intensity modulator (IM) with a simultaneously suppressed optical central carrier. By adjusting the bias voltage and utilizing proper peak-to-peak voltage of the RF signal drive on the IM, undesired sidebands can be suppressed. Based on this rule, an experiment was performed to generate 48 and 72-GHz optical mm-waves using a sinusoidal clock source running at only 12 GHz.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Modulation of alpha-synuclein toxicity in yeast using a novel microfluidic-based gradient generator.

    PubMed

    Fernandes, João Tiago S; Tenreiro, Sandra; Gameiro, Andreia; Chu, Virginia; Outeiro, Tiago F; Conde, João P

    2014-10-21

    Parkinson's disease (PD) is a common age-associated neurodegenerative disorder. The protein α-synuclein (aSyn) is a key factor in PD both due to its association with familial and sporadic cases and because it is the main component of the pathological protein aggregates known as Lewy bodies. However, the precise cellular effects of aSyn aggregation are still elusive. Here, we developed an elastomeric microfluidic device equipped with a chemical gradient generator and 9 chambers containing cell traps to study aSyn production and aggregation in Saccharomyces cerevisiae. This study involved capturing single cells, exposing them to specific chemical environments and imaging the expression of aSyn by means of a GFP fusion (aSyn-GFP). Using a galactose (GAL) gradient we modulated aSyn expression and, surprisingly, by tracking the behavior of single cells, we found that the response of individual cells in a population to a given stimulus can differ widely. To study the combined effect of environmental factors and aSyn expression levels, we exposed cells to a gradient of FeCl3. We found a dramatic increase in the percentage of cells displaying aSyn inclusions from 27% to 96%. Finally, we studied the effects of ascorbic acid, an antioxidant, on aSyn aggregation and found a significant reduction in the percentage of cells bearing aSyn inclusions from 87% to 37%. In summary, the device developed here offers a powerful way of studying aSyn biology with single-cell resolution and high throughput using genetically modified yeast cells. PMID:25167219

  13. Multi-function Mach-Zehnder modulator for pulse shaping and generation.

    PubMed

    Gao, Jing; Wu, Hui

    2016-09-19

    We present a multi-function electronic-photonic integrated circuit (EPIC) design which exploits a new operation mode of a Mach-Zehnder modulator (MZM). Different from the conventional design, the two arms of the modulator are driven by time-shifted signals of tunable amplitude. We study its operation in the linear and quadratic regions where the MZM is biased at π/2 and π initial phase difference, respectively. In the linear region, the modulator sums the waveforms of the driving signals in the two arms, which can be used to add pre-emphasis function to the modulator, and hence it obviates an electrical pre-emphasis driver. Furthermore, when operating in the quadratic region, the modulator can produce optical pulses with tunable pulse width at double clock rate. Prototype circuits are designed first using a suit of device, electromagnetic simulators to build compact models, and then importing into a photonic circuit simulator for complete circuit performance evaluation. PMID:27661958

  14. Experimental generation of longitudinally-modulated electron beams using an emittance exchange technique

    SciTech Connect

    Sun, Y.-E; Piot, P.; Johnson, A.; Lumpkin, A.; Maxwell, T.; Ruan, J.; Thurman-Keup, R.; /FERMILAB

    2010-08-01

    We report our experimental demonstration of longitudinal phase space modulation using a transverse-to-longitudinal emittance exchange technique. The experiment is carried out at the A0 photoinjector at Fermi National Accelerator Lab. A vertical multi-slit plate is inserted into the beamline prior to the emittance exchange, thus introducing beam horizontal profile modulation. After the emittance exchange, the longitudinal phase space coordinates (energy and time structures) of the beam are modulated accordingly. This is a clear demonstration of the transverse-to-longitudinal phase space exchange. In this paper, we present our experimental results on the measurement of energy profile as well as numerical simulations of the experiment.

  15. High-purity 60GHz band millimeter-wave generation based on optically injected semiconductor laser under subharmonic microwave modulation.

    PubMed

    Fan, Li; Xia, Guangqiong; Chen, Jianjun; Tang, Xi; Liang, Qing; Wu, Zhengmao

    2016-08-01

    Based on an optically injected semiconductor laser (OISL) operating at period-one (P1) nonlinear dynamical state, high-purity millimeter-wave generation at 60 GHz band is experimentally demonstrated via 1/4 and 1/9 subharmonic microwave modulation (the order of subharmonic is with respect to the frequency fc of the acquired 60 GHz band millimeter-wave but not the fundamental frequency f0 of P1 oscillation). Optical injection is firstly used to drive a semiconductor laser into P1 state. For the OISL operates at P1 state with a fundamental frequency f0 = 49.43 GHz, by introducing 1/4 subharmonic modulation with a modulation frequency of fm = 15.32 GHz, a 60 GHz band millimeter-wave with central frequency fc = 61.28 GHz ( = 4fm) is experimentally generated, whose linewidth is below 1.6 kHz and SSB phase noise at offset frequency 10 kHz is about -96 dBc/Hz. For fm is varied between 13.58 GHz and 16.49 GHz, fc can be tuned from 54.32 GHz to 65.96 GHz under matched modulation power Pm. Moreover, for the OISL operates at P1 state with f0 = 45.02 GHz, a higher order subharmonic modulation (1/9) is introduced into the OISL for obtaining high-purity 60 GHz band microwave signal. With (fm, Pm) = (7.23 GHz, 13.00 dBm), a microwave signal at 65.07 GHz ( = 9fm) with a linewidth below 1.6 kHz and a SSB phase noise less than -98 dBc/Hz is experimentally generated. Also, the central frequency fc can be tuned in a certain range through adjusting fm and selecting matched Pm.

  16. High-purity 60GHz band millimeter-wave generation based on optically injected semiconductor laser under subharmonic microwave modulation.

    PubMed

    Fan, Li; Xia, Guangqiong; Chen, Jianjun; Tang, Xi; Liang, Qing; Wu, Zhengmao

    2016-08-01

    Based on an optically injected semiconductor laser (OISL) operating at period-one (P1) nonlinear dynamical state, high-purity millimeter-wave generation at 60 GHz band is experimentally demonstrated via 1/4 and 1/9 subharmonic microwave modulation (the order of subharmonic is with respect to the frequency fc of the acquired 60 GHz band millimeter-wave but not the fundamental frequency f0 of P1 oscillation). Optical injection is firstly used to drive a semiconductor laser into P1 state. For the OISL operates at P1 state with a fundamental frequency f0 = 49.43 GHz, by introducing 1/4 subharmonic modulation with a modulation frequency of fm = 15.32 GHz, a 60 GHz band millimeter-wave with central frequency fc = 61.28 GHz ( = 4fm) is experimentally generated, whose linewidth is below 1.6 kHz and SSB phase noise at offset frequency 10 kHz is about -96 dBc/Hz. For fm is varied between 13.58 GHz and 16.49 GHz, fc can be tuned from 54.32 GHz to 65.96 GHz under matched modulation power Pm. Moreover, for the OISL operates at P1 state with f0 = 45.02 GHz, a higher order subharmonic modulation (1/9) is introduced into the OISL for obtaining high-purity 60 GHz band microwave signal. With (fm, Pm) = (7.23 GHz, 13.00 dBm), a microwave signal at 65.07 GHz ( = 9fm) with a linewidth below 1.6 kHz and a SSB phase noise less than -98 dBc/Hz is experimentally generated. Also, the central frequency fc can be tuned in a certain range through adjusting fm and selecting matched Pm. PMID:27505789

  17. Design, fabrication, test, qualification, and price analysis of third generation design solar cell modules

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The fabrication of solar cell modules is detailed with emphasis upon laminating and interconnecting the panels that hold the simicrystalline silicon cells. Design problems and enviromental tests are described as well as performance characteristics.

  18. Fault-tolerant NAND-flash memory module for next-generation scientific instruments

    NASA Astrophysics Data System (ADS)

    Lange, Tobias; Michel, Holger; Fiethe, Björn; Michalik, Harald; Walter, Dietmar

    2015-10-01

    Remote sensing instruments on today's space missions deliver a high amount of data which is typically evaluated on ground. Especially for deep space missions the telemetry downlink is very limited which creates the need for the scientific evaluation and thereby a reduction of data volume already on-board the spacecraft. A demanding example is the Polarimetric and Helioseismic Imager (PHI) instrument on Solar Orbiter. To enable on-board offline processing for data reduction, the instrument has to be equipped with a high capacity memory module. The module is based on non-volatile NAND-Flash technology, which requires more advanced operation than volatile DRAM. Unlike classical mass memories, the module is integrated into the instrument and allows readback of data for processing. The architecture and safe operation of such kind of memory module is described in the following paper.

  19. Apparatus and Method for Generating Thrust Using a Two Dimensional, Asymmetrical Capacitor Module

    NASA Technical Reports Server (NTRS)

    Campbell, Jonathan W. (Inventor)

    2001-01-01

    A capacitor module system is provided for creating a thrust force. The system includes a capacitor module provided with a first conductive element having a cylindrical geometry. The first conductive element can be a hollow cylinder or a solid cylinder. The capacitor module also includes a second conductive element axially spaced from the first conductive element and of smaller axial extent. The second conductive element can be a flat disk, a dome, or a conductive tip at the end of a dielectric rod. A dielectric element is disposed between the first conductive element and the second conductive element. The system also includes a high voltage source having first and second terminals connected respectively to the first and second conductive elements. The high voltage source applies a high voltage to the conductive elements of sufficient value to create a thrust force on the module inducing movement thereof.

  20. Electrically controlled second-harmonic generation in silicon-compatible plasmonic slot waveguides: a new modulation scheme.

    PubMed

    Zhang, Jihua; Cassan, Eric; Zhang, Xinliang

    2014-07-01

    The possible realization of an active electro-optical control of the nonlinear second-harmonic generation (SHG) mechanism in a plasmonic slot waveguide is theoretically investigated. Both the conventional SHG and the electrically induced SHG are taken into account with a moderate pump power of 40 mW at the fundamental wavelength (1550 nm). The generated power of the second-harmonic frequency can be modulated by the applied voltage in a quadratic and almost linear form for centrosymmetric and noncentrosymmetric nonlinear polymers integrated in the slot, respectively. Converted power up to 140 μW within a short distance of only 16 μm is predicted for a voltage of 10 V. This mechanism may open a new route to realize high-speed advanced modulations or inversely to detect ultrafast electrical signals.

  1. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    DOE PAGESBeta

    Zhu, Xiaofang; Broemmelsiek, Daniel R.; Shin, Young -Min; Fermi National Accelerator Lab.

    2015-10-28

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ –0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~more » 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). As a result, the theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.« less

  2. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Broemmelsiek, D. R.; Shin, Y.-M.

    2015-10-01

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ -0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~ 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). The theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.

  3. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    SciTech Connect

    Zhu, Xiaofang; Broemmelsiek, Daniel R.; Shin, Young -Min

    2015-10-28

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ –0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~ 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). As a result, the theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.

  4. Fourth-Generation Progestins Inhibit 3β-Hydroxysteroid Dehydrogenase Type 2 and Modulate the Biosynthesis of Endogenous Steroids

    PubMed Central

    Louw-du Toit, Renate; Perkins, Meghan S.; Snoep, Jacky L.; Storbeck, Karl-Heinz; Africander, Donita

    2016-01-01

    Progestins used in contraception and hormone replacement therapy are synthetic compounds designed to mimic the actions of the natural hormone progesterone and are classed into four consecutive generations. The biological actions of progestins are primarily determined by their interactions with steroid receptors, and factors such as metabolism, pharmacokinetics, bioavailability and the regulation of endogenous steroid hormone biosynthesis are often overlooked. Although some studies have investigated the effects of select progestins on a few steroidogenic enzymes, studies comparing the effects of progestins from different generations are lacking. This study therefore explored the putative modulatory effects of progestins on de novo steroid synthesis in the adrenal by comparing the effects of select progestins from the respective generations, on endogenous steroid hormone production by the H295R human adrenocortical carcinoma cell line. Ultra-performance liquid chromatography/tandem mass spectrometry analysis showed that the fourth-generation progestins, nestorone (NES), nomegestrol acetate (NoMAC) and drospirenone (DRSP), unlike the progestins selected from the first three generations, modulate the biosynthesis of several endogenous steroids. Subsequent assays performed in COS-1 cells expressing human 3βHSD2, suggest that these progestins modulate the biosynthesis of steroid hormones by inhibiting the activity of 3βHSD2. The Ki values determined for the inhibition of human 3βHSD2 by NES (9.5 ± 0.96 nM), NoMAC (29 ± 7.1 nM) and DRSP (232 ± 38 nM) were within the reported concentration ranges for the contraceptive use of these progestins in vivo. Taken together, our results suggest that newer, fourth-generation progestins may exert both positive and negative physiological effects via the modulation of endogenous steroid hormone biosynthesis. PMID:27706226

  5. Soliton generation from an actively mode-locked fiber laser incorporating an electro-optic fiber modulator.

    PubMed

    Malmström, Mikael; Margulis, Walter; Tarasenko, Oleksandr; Pasiskevicius, Valdas; Laurell, Fredrik

    2012-01-30

    This work demonstrates an actively mode-locked fiber laser operating in soliton regime and employing an all-fiber electro-optic modulator. Nonlinear polarization rotation is utilized for femtosecond pulse generation. Stable operation of the all-fiber ring laser is readily achieved at a fundamental repetition rate of 2.6 MHz and produces 460 fs pulses with a spectral bandwidth of 5.3 nm.

  6. 20. Public Works Department Drawing 461M7 (1943), 'Sulphuric Acid Storage ...

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

    20. Public Works Department Drawing 461-M-7 (1943), 'Sulphuric Acid Storage System-Building 463 Details' - Mare Island Naval Shipyard, Acid Mixing Facility, California Avenue & E Street, Vallejo, Solano County, CA

  7. Development of Low-Cost Remote-Control Generators Based on BiTe Thermoelectric Modules

    NASA Astrophysics Data System (ADS)

    Juanicó, Luis E.; Rinalde, Fabián; Taglialavore, Eduardo; Molina, Marcelo

    2013-07-01

    This paper presents a new thermogenerator based on moderate-temperature (up to 175°C) BiTe modules available on the open market. Despite this handicap relative to commercial thermogenerators based on high-temperature proprietary-technology PbBi modules (up to 560°C), this new design may become economically competitive due to its innovative thermal sink. Our thermal sink is based on a free-convection water loop built with standard tubing and household hot-water radiators, leading to a more practical, modular design. So, the specific cost of about 55,000 USD/kW obtained for this 120-W prototype is improved to 33,000 USD/kW for a 1-kW unit, which represents about half the price of commercial thermogenerators. Moreover, considering recently launched BiTe modules (that withstand up to 320°C), our proposition could have an even more favorable outlook.

  8. Photo-generated metamaterials induce modulation of CW terahertz quantum cascade lasers

    PubMed Central

    Mezzapesa, Francesco P.; Columbo, Lorenzo L.; Rizza, Carlo; Brambilla, Massimo; Ciattoni, Alessardro; Dabbicco, Maurizio; Vitiello, Miriam S.; Scamarcio, Gaetano

    2015-01-01

    Periodic patterns of photo-excited carriers on a semiconductor surface profoundly modifies its effective permittivity, creating a stationary all-optical quasi-metallic metamaterial. Intriguingly, one can tailor its artificial birefringence to modulate with unprecedented degrees of freedom both the amplitude and phase of a quantum cascade laser (QCL) subject to optical feedback from such an anisotropic reflector. Here, we conceive and devise a reconfigurable photo-designed Terahertz (THz) modulator and exploit it in a proof-of-concept experiment to control the emission properties of THz QCLs. Photo-exciting sub-wavelength metastructures on silicon, we induce polarization-dependent changes in the intra-cavity THz field, that can be probed by monitoring the voltage across the QCL terminals. This inherently flexible approach promises groundbreaking impact on THz photonics applications, including THz phase modulators, fast switches, and active hyperbolic media. PMID:26549166

  9. Photo-generated metamaterials induce modulation of CW terahertz quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Mezzapesa, Francesco P.; Columbo, Lorenzo L.; Rizza, Carlo; Brambilla, Massimo; Ciattoni, Alessardro; Dabbicco, Maurizio; Vitiello, Miriam S.; Scamarcio, Gaetano

    2015-11-01

    Periodic patterns of photo-excited carriers on a semiconductor surface profoundly modifies its effective permittivity, creating a stationary all-optical quasi-metallic metamaterial. Intriguingly, one can tailor its artificial birefringence to modulate with unprecedented degrees of freedom both the amplitude and phase of a quantum cascade laser (QCL) subject to optical feedback from such an anisotropic reflector. Here, we conceive and devise a reconfigurable photo-designed Terahertz (THz) modulator and exploit it in a proof-of-concept experiment to control the emission properties of THz QCLs. Photo-exciting sub-wavelength metastructures on silicon, we induce polarization-dependent changes in the intra-cavity THz field, that can be probed by monitoring the voltage across the QCL terminals. This inherently flexible approach promises groundbreaking impact on THz photonics applications, including THz phase modulators, fast switches, and active hyperbolic media.

  10. Photo-generated metamaterials induce modulation of CW terahertz quantum cascade lasers.

    PubMed

    Mezzapesa, Francesco P; Columbo, Lorenzo L; Rizza, Carlo; Brambilla, Massimo; Ciattoni, Alessandro; Ciattoni, Alessardro; Dabbicco, Maurizio; Vitiello, Miriam S; Scamarcio, Gaetano

    2015-11-09

    Periodic patterns of photo-excited carriers on a semiconductor surface profoundly modifies its effective permittivity, creating a stationary all-optical quasi-metallic metamaterial. Intriguingly, one can tailor its artificial birefringence to modulate with unprecedented degrees of freedom both the amplitude and phase of a quantum cascade laser (QCL) subject to optical feedback from such an anisotropic reflector. Here, we conceive and devise a reconfigurable photo-designed Terahertz (THz) modulator and exploit it in a proof-of-concept experiment to control the emission properties of THz QCLs. Photo-exciting sub-wavelength metastructures on silicon, we induce polarization-dependent changes in the intra-cavity THz field, that can be probed by monitoring the voltage across the QCL terminals. This inherently flexible approach promises groundbreaking impact on THz photonics applications, including THz phase modulators, fast switches, and active hyperbolic media.

  11. Photo-generated metamaterials induce modulation of CW terahertz quantum cascade lasers.

    PubMed

    Mezzapesa, Francesco P; Columbo, Lorenzo L; Rizza, Carlo; Brambilla, Massimo; Ciattoni, Alessandro; Ciattoni, Alessardro; Dabbicco, Maurizio; Vitiello, Miriam S; Scamarcio, Gaetano

    2015-01-01

    Periodic patterns of photo-excited carriers on a semiconductor surface profoundly modifies its effective permittivity, creating a stationary all-optical quasi-metallic metamaterial. Intriguingly, one can tailor its artificial birefringence to modulate with unprecedented degrees of freedom both the amplitude and phase of a quantum cascade laser (QCL) subject to optical feedback from such an anisotropic reflector. Here, we conceive and devise a reconfigurable photo-designed Terahertz (THz) modulator and exploit it in a proof-of-concept experiment to control the emission properties of THz QCLs. Photo-exciting sub-wavelength metastructures on silicon, we induce polarization-dependent changes in the intra-cavity THz field, that can be probed by monitoring the voltage across the QCL terminals. This inherently flexible approach promises groundbreaking impact on THz photonics applications, including THz phase modulators, fast switches, and active hyperbolic media. PMID:26549166

  12. A Novel Optimization Method for the Electric Topology of Thermoelectric Modules Used in an Automobile Exhaust Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Quan, Rui; Tang, Xinfeng; Quan, Shuhai; Huang, Liang

    2013-07-01

    Based on Bi2Te3 thermoelectric modules, a kind of automobile exhaust thermoelectric generator (AETEG) with a single-column cold-source structure was designed. To enhance its net power and efficiency, the output performance of all the thermoelectric modules was tested with a temperature monitoring unit and voltage monitoring unit, and modeled using a back-propagation (BP) neural network based on various hot-source temperatures, cold-source temperatures, load currents, and contact pressures according to the temperature distribution of the designed heat exchanger and cooling system. Then, their electric topology (series or parallel hybrid) was optimized using a genetic algorithm to achieve the maximum peak power of the AETEG. From the experimental results, compared with when all the thermoelectric modules were connected only in series or parallel at random, it is concluded that the AETEG performance is evidently affected by the electric topology of all the single thermoelectric modules. The optimized AETEG output power is greatly superior to the other two investigated designs, validating the proposed optimized electric topology as both feasible and practical.

  13. Third generation design solar cell module LSA task 5, large scale production

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A total of twelve (12) preproduction modules were constructed, tested, and delivered. A concept to the frame assembly was designed and proven to be quite reliable. This frame design, as well as the rest of the assembly, was designed with future high volume production and the use of automated equipment in mind.

  14. Frequency measurement of THz waves by electro-optic sampling using Mach-Zehnder-modulator-based flat comb generator

    NASA Astrophysics Data System (ADS)

    Morohashi, Isao; Kirigaya, Mayu; Kaneko, Yuta; Katayama, Ikufumi; Sakamoto, Takahide; Sekine, Norihiko; Kasamatsu, Akifumi; Hosako, Iwao

    2016-02-01

    In the recent progress in terahertz (THz) devices, various kinds of source devices, such as resonant tunneling diodes, quantum cascade lasers and so forth, have been developed. Frequency measurement of THz radiations, which can operate in high speed and at room-temperature, is important for development of high-performance THz source devices. Recently, frequency measurement using optical combs are demonstrated by several groups. In these techniques, modelocked lasers (MLLs) are used for optical comb source, so that phase-locking techniques are required in order to stabilize the repetition frequency of the MLLs. On the other hand, a modulator-based optical comb generator has high accuracy and stability in the comb spacing, which is comparable to that of microwave signal driving the modulator. Thus it is suitable for frequency measurement of THz waves. In this paper, we demonstrated frequency measurement of THz waves using a Mach-Zehnder-modulator-based flat comb generator (MZ-FCG). The frequency measurement was carried out by an electro-optic (EO) sampling method, where an optical two-tone signal extracted from the optical comb generated by the MZ-FCG was used for the probe light. A 100 GHz signal generated by a W-band frequency multiplier and the probe beam collinearly traveled through an EO crystal, and beat signals between them were measured by a combination of a balanced photodetector and a spectrum analyzer. As a result, frequency measurement of the 100 GHz wave was successfully demonstrated, in which the linewidth of the beat signal was less than 1 Hz.

  15. Photonic generation of a phase-coded microwave signal based on a single dual-drive Mach-Zehnder modulator.

    PubMed

    Tang, Zhenzhou; Zhang, Tingting; Zhang, Fangzheng; Pan, Shilong

    2013-12-15

    A compact scheme for photonic generation of a phase-coded microwave signal using a dual-drive Mach-Zehnder modulator (DMZM) is proposed and experimentally demonstrated. In the proposed scheme, the radio frequency (RF) carrier and the coding signal are sent to the two RF ports of the DMZM, respectively. By properly setting the amplitude of the coding signal and the bias voltage of the DMZM, an exact π-phase-shift phase-coded microwave signal is generated. The proposed scheme has a simple structure since only a single DMZM is required. In addition, good frequency tunability is achieved because no frequency-dependent electrical devices or wavelength-dependent optical devices are applied. The feasibility of the proposed scheme is verified by experiment. 2 or 2.5 Gb/s phase-coded 10 and 20 GHz microwave signals are successfully generated.

  16. Generation of linear frequency modulation signal with reduced round-off error using pulse-output Direct Digital Synthesis technique.

    PubMed

    Peng, Cheng Y; Ma, Xiao C; Yan, She F; Yang, Li

    2014-02-01

    The pulse-output Direct Digital Synthesis (DDS), in which the overflow signal of the phase accumulator is used for the pulse output, can be easily implemented due to its simple hardware architecture and low algorithm complexity. This paper introduces the fundamentals for generating Linear Frequency Modulation (LFM) pulse using pulse-output DDS technique. Error introducing mechanisms that affect the accuracy of signal's duration, initial phase, and frequency are studied. Extensive analysis of round-off error is given. A modified hardware architecture for LFM pulse generation with reduced round-off error is proposed. Experiment results are given, which shows that the proposed generator is promising in applications such as sonar transmitters.

  17. Significant foreshock activities of M>7.5 earthquakes in the Kuril subduction zone

    NASA Astrophysics Data System (ADS)

    Harada, T.; Yokoi, S.; Satake, K.

    2014-12-01

    In the Kuril subduction zone, some M>7.5 earthquakes are accompanied by significant foreshock activities, providing a good opportunity to understand the characteristics of foreshocks for large interplate events such as occur along the Japan Trench and Nankai Trough etc. Some preliminary results from our examination of the foreshock sequences are as follows. Relocated foreshocks tend to migrate with time toward the trench axis. Foreshock distributions of the interplate earthquakes do not overlap with the large coseismic slips (asperities) of the mainshocks. Foreshocks of the 2007 northern Kuril outer-rise event, however, were distributed on the entire rupture area. Foreshock sequences seem to be limited in the regions where the background seismicity rates are relatively high. The foreshock activities were found in the examination of the space-time pattern of M>7 events along the northern Japan to Kuril trench since 1913 (e.g. Harada, Satake, and Ishibashi, 2011:AGU, 2012:AOGS). The large earthquakes preceded by active foreshock sequences are: the 2006 (M8.3), 2007 (M8.1) offshore Simushir earthquakes, the 1963 (M8.5), 1991 (M7.6), 1995 (M7.9) offshore Urup events, the 1978 (M7.8) offshore Iturup events, the 1969 (M8.2) offshore Shikotan event. In contrast, M>7.5 interplate earthquakes offshore Hokkaido (1952 (M8.1), 1973 (M7.8), 2003 (M8.1)) and intraslab earthquakes (1958 (M8.3), 1978 (M7.8), 1993 (M7.6), 1994 (M8.3)) had few or no foreshocks. In the examination of the active foreshocks, we relocated foreshocks by the Modified JHD method (Hurukawa, 1995), compared relocated foreshock areas with mainshock coseismic slip distributions estimated by the teleseismic body-wave inversion (Kikuchi and Kanamori, 2003), and examined the relation between active foreshock sequences and regional background seismicity. This study was supported by the MEXT's "New disaster mitigation research project on Mega thrust earthquakes around Nankai/Ryukyu subduction zones".

  18. Generation of second harmonic light with a wavelength of 560 nm in a compact module

    NASA Astrophysics Data System (ADS)

    Hofmann, Julian; Sahm, Alexander; John, Wilfred; Bugge, Frank; Paschke, Katrin

    2016-09-01

    We demonstrate a continuous wave 133 mW laser module at 560.5 nm on a 50 mm·10 mm optical bench. The setup consists of a 1121 nm distributed Bragg reflector ridge waveguide laser and a MgO:LiNbO3 quasi-phase matched ridge waveguide crystal, which are coupled by a grin lens, as well as two cylindrical lenses for beam collimation behind the crystal. A novel approach to ensure phase matching is used. The laser and the crystal are stabilized by the same heat sink and only the wavelength of the laser is tuned by heating the distributed Bragg reflector section of the laser. This reduces the influence of temperature variations on the module's performance enabling operation with output power variations < 10 % over a temperature range of 20 K. The size and robustness against temperature variations of this setup make it an interesting candidate for future biomedical applications.

  19. Development and Results of a First Generation Least Expensive Approach to Fission: Module Tests and Results

    NASA Technical Reports Server (NTRS)

    Houts, Mike; Godfroy, Tom; Pederson, Kevin; Sena, J. Tom; VanDyke, Melissa; Dickens, Ricky; Reid, Bob J.; Martin, Jim

    2000-01-01

    The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal-hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments and identifies future tests to be performed.

  20. Local generation of electrostatic bursts at Comet Giacobini-Zinner - Modulation by steepened magnetosonic waves

    NASA Technical Reports Server (NTRS)

    Brinca, Armando L.; Tsurutani, Bruce T.; Scarf, Frederick L.

    1989-01-01

    The ICE spacecraft observed in the vicinity of Comet Giacobini-Zinner electrostatic noise with burstlike features seemingly modulated by the relative orientation of the interplanetary magnetic field and the solar wind velocity. The adequacy of ion acousticlike instabilities stimulated by photoelectron or newborn ion beams to the interpretation of the electrostatic bursts is discussed. It is concluded that the mode fed by the photoelectrons exhibits characteristics compatible with the observations.

  1. Generator module architecture for a large solid oxide fuel cell power plant

    SciTech Connect

    Gillett, James E.; Zafred, Paolo R.; Riggle, Matthew W.; Litzinger, Kevin P.

    2013-06-11

    A solid oxide fuel cell module contains a plurality of integral bundle assemblies, the module containing a top portion with an inlet fuel plenum and a bottom portion receiving air inlet feed and containing a base support, the base supports dense, ceramic exhaust manifolds which are below and connect to air feed tubes located in a recuperator zone, the air feed tubes passing into the center of inverted, tubular, elongated, hollow electrically connected solid oxide fuel cells having an open end above a combustion zone into which the air feed tubes pass and a closed end near the inlet fuel plenum, where the fuel cells comprise a fuel cell stack bundle all surrounded within an outer module enclosure having top power leads to provide electrical output from the stack bundle, where the fuel cells operate in the fuel cell mode and where the base support and bottom ceramic air exhaust manifolds carry from 85% to all 100% of the weight of the stack, and each bundle assembly has its own control for vertical and horizontal thermal expansion control.

  2. Electrooptic light modulation and second-harmonic generation in novel diazo-dye-substituted poled polymers

    NASA Astrophysics Data System (ADS)

    Shuto, Yoshito; Amano, Michiyuki; Kaino, Toshikuni

    1991-11-01

    The nonlinear-optical susceptibilities, chi exp (2), of a diazo-dye-substituted polymer poled with high electric fields were determined experimentally and theoretically. The electrooptic modulation of He-Ne laser light in a traveling-wave channel-waveguide modulator using the diazo-dye-substituted poled polymer is reported, and the linear electrooptic coefficient of the poled polymer is estimated from a measured half-wave voltage. The polymer studied is a poly(methyl methacrylate) copolymerized with a methacrylate ester of the dicyanovinyl-terminated diazo dye derivative. This polymer is called 3RDCVXY. The corona-poled 3RDCVXY polymer exhibits a chi exp (2) value of 1 x 10 exp -6 esu at 1.06 micron. The thermal stability is excellent even at 80 C. The poled 3RDCVXY polymer film shows a linear electrooptic coefficient as high as 40 pm/V at 0.633 micron. An electrooptical light modulation in the channel 3RDCVXY polymer waveguides with a half-wave voltage as low as 5 V was obtained.

  3. Instructional Topics in Educational Measurement (ITEMS) Module: Using Automated Processes to Generate Test Items

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Lai, Hollis

    2013-01-01

    Changes to the design and development of our educational assessments are resulting in the unprecedented demand for a large and continuous supply of content-specific test items. One way to address this growing demand is with automatic item generation (AIG). AIG is the process of using item models to generate test items with the aid of computer…

  4. Real-time computer-generated hologram by means of liquid-crystal television spatial light modulator

    NASA Technical Reports Server (NTRS)

    Mok, Fai; Psaltis, Demetri; Diep, Joseph; Liu, Hua-Kuang

    1986-01-01

    The usefulness of an inexpensive liquid-crystal television) (LCTV) as a spatial light modulator for coherent-optical processing in the writing and reconstruction of a single computer-generated hologram has been demonstrated. The thickness nonuniformities of the LCTV screen were examined in a Mach-Zehnder interferometer, and the phase distortions were successfully removed using a technique in which the LCTV screen was submerged in a liquid gate filled with an index-matching nonconductive mineral oil with refractive index of about 1.45.

  5. Efficient generation of fast ions from surface modulated nanostructure targets irradiated by high intensity short-pulse lasers

    SciTech Connect

    Andreev, Alexander; Kumar, Naveen; Pukhov, Alexander; Platonov, Konstantin

    2011-10-15

    It's shown that the imposition of sub-laser wavelength relief structures on the surface of mass-limited-targets results into several folds higher short-pulse laser absorption, and consequently the efficient generation of fast ions. The optimum relief parameters for enhanced short-pulse laser absorption and higher ion acceleration are estimated numerically by particle-in-cell simulations and then corroborated by analytical scalings. The stability of the pre-imposed surface modulation during the laser pulse foil interaction is also examined.

  6. Addressable, large-field second harmonic generation microscopy based on 2D acousto-optical deflector and spatial light modulator

    PubMed Central

    Shao, Yonghong; Liu, Honghai; Qin, Wan; Qu, Junle; Peng, Xiang; Niu, Hanben

    2013-01-01

    We present an addressable, large-field second harmonic generation microscope by combining a 2D acousto-optical deflector with a spatial light modulator. The SLM shapes an incoming mode-locked, near-infrared Ti:Sapphire laser beam into a multifocus array, which can be rapidly scanned by changing the incident angle of the laser beam using a 2D acousto-optical deflector. Compared to the single-beam-scan technique, the multifocus array scan can increase the scanning rate and the field-of-view size with the multi-region imaging ability. PMID:24307756

  7. Simulation for Wind Turbine Generators -- With FAST and MATLAB-Simulink Modules

    SciTech Connect

    Singh, M.; Muljadi, E.; Jonkman, J.; Gevorgian, V.; Girsang, I.; Dhupia, J.

    2014-04-01

    This report presents the work done to develop generator and gearbox models in the Matrix Laboratory (MATLAB) environment and couple them to the National Renewable Energy Laboratory's Fatigue, Aerodynamics, Structures, and Turbulence (FAST) program. The goal of this project was to interface the superior aerodynamic and mechanical models of FAST to the excellent electrical generator models found in various Simulink libraries and applications. The scope was limited to Type 1, Type 2, and Type 3 generators and fairly basic gear-train models. Future work will include models of Type 4 generators and more-advanced gear-train models with increased degrees of freedom. As described in this study, implementation of the developed drivetrain model enables the software tool to be used in many ways. Several case studies are presented as examples of the many types of studies that can be performed using this tool.

  8. NADH oxidase-dependent CD39 expression by CD8(+) T cells modulates interferon gamma responses via generation of adenosine.

    PubMed

    Bai, Aiping; Moss, Alan; Rothweiler, Sonja; Longhi, Maria Serena; Wu, Yan; Junger, Wolfgang G; Robson, Simon C

    2015-11-09

    Interferon gamma (IFNγ)-producing CD8(+) T cells (Tc1) play important roles in immunological disease. We now report that CD3/CD28-mediated stimulation of CD8(+) T cells to generate Tc1 cells, not only increases IFNγ production but also boosts the generation of reactive oxygen species (ROS) and augments expression of CD39. Inhibition of NADPH oxidases or knockdown of gp91phox in CD8(+) T cells abrogates ROS generation, which in turn modulates JNK and NFκB signalling with decreases in both IFNγ levels and CD39 expression. CD39(+)CD8(+) T cells substantially inhibit IFNγ production by CD39(-)CD8(+) T cells via the paracrine generation of adenosine, which is operational via adenosine type 2A receptors. Increases in numbers of CD39(+)CD8(+) T cells and associated enhancements in ROS signal transduction are noted in cells from patients with Crohn's disease. Our findings provide insights into Tc1-mediated IFNγ responses and ROS generation and link these pathways to CD39/adenosine-mediated effects in immunological disease.

  9. Systematic monitoring and evaluation of M7 scanner performance and data quality

    NASA Technical Reports Server (NTRS)

    Stewart, S.; Christenson, D.; Larsen, L.

    1974-01-01

    An investigation was conducted to provide the information required to maintain data quality of the Michigan M7 Multispectral scanner by systematic checks on specific system performance characteristics. Data processing techniques which use calibration data gathered routinely every mission have been developed to assess current data quality. Significant changes from past data quality are thus identified and attempts made to discover their causes. Procedures for systematic monitoring of scanner data quality are discussed. In the solar reflective region, calculations of Noise Equivalent Change in Radiance on a permission basis are compared to theoretical tape-recorder limits to provide an estimate of overall scanner performance. M7 signal/noise characteristics are examined.

  10. Directly modulated and fully tunable hybrid silicon lasers for future generation of coherent colorless ONU.

    PubMed

    de Valicourt, G; Le Liepvre, A; Vacondio, F; Simonneau, C; Lamponi, M; Jany, C; Accard, A; Lelarge, F; Make, D; Poingt, F; Duan, G H; Fedeli, J-M; Messaoudene, S; Bordel, D; Lorcy, L; Antona, J-C; Bigo, S

    2012-12-10

    We propose and demonstrate asymmetric 10 Gbit/s upstream--100 Gbit/s downstream per wavelength colorless WDM/TDM PON using a novel hybrid-silicon chip integrating two tunable lasers. The first laser is directly modulated in burst mode for upstream transmission over up to 25 km of standard single mode fiber and error free transmission over 4 channels across the C-band is demonstrated. The second tunable laser is successfully used as local oscillator in a coherent receiver across the C-band simultaneously operating with the presence of 80 downstream co-channels.

  11. Impact: a low cost, reconfigurable, digital beamforming common module building block for next generation phased arrays

    NASA Astrophysics Data System (ADS)

    Paulsen, Lee; Hoffmann, Ted; Fulton, Caleb; Yeary, Mark; Saunders, Austin; Thompson, Dan; Chen, Bill; Guo, Alex; Murmann, Boris

    2015-05-01

    Phased array systems offer numerous advantages to the modern warfighter in multiple application spaces, including Radar, Electronic Warfare, Signals Intelligence, and Communications. However, a lack of commonality in the underlying technology base for DoD Phased Arrays has led to static systems with long development cycles, slow technology refreshes in response to emerging threats, and expensive, application-specific sub-components. The IMPACT module (Integrated Multi-use Phased Array Common Tile) is a multi-channel, reconfigurable, cost-effective beamformer that provides a common building block for multiple, disparate array applications.

  12. Ultrashort light pulses generated from modulation instability: background removal and soliton content

    NASA Astrophysics Data System (ADS)

    Mahnke, Christoph; Mitschke, Fedor

    2014-07-01

    Modulation instability can be used to convert a continuous light wave into a train of pulses on a constant background. It is a longstanding discussion whether these pulses can be converted into solitons. We clarify the situation by using a more general mathematical context, invoking the Akhmediev breather, Peregrine soliton and Kuznetsov-Ma soliton solutions of the wave equation, and suggest the use of a Mach-Zehnder interferometer to remove the background. Expressions for the pulse widths and peak powers thus obtained are presented, and their soliton content is determined. It turns out that more than 95 % of each pulse's energy can be converted to a soliton.

  13. FOST 2 Upgrade with Hollow-Fiber CTA FO Module and Generation of Osmotic Agent for Microorganism Growth Studies

    NASA Technical Reports Server (NTRS)

    Parodi, Jurek; Mangado, Jaione Romero; Stefanson, Ofir; Flynn, Michael; Shaw, Hali; Beeler, David

    2016-01-01

    FOST 2 is an integrated membrane system that incorporates a forward osmosis subsystem and a reverse osmosis subsystem working in series. It has been designed as a post treatment system to process the effluent from the Membrane Aerated Biological Reactor developed at NASA Johnson Space Center and Texas Tech University. Its function is to remove dissolved solids residual such as ammonia and suspended solids, as well as to provide a physical barrier to microbial and viral contamination. A tubular CTA membrane module from HTI and a flat-sheet lipid-base membrane module from Porifera were integrated and tested on FOST 2 in the past, using both a bioreactor's effluent and greywater as the feed solution. This paper documents the performance of FOST 2 after its upgrade with a hollow-fiber CTA membrane module from Toyobo, treating real black-water to generate the osmotic agent solution necessary to conduct growth studies of genetically engineered microorganism for the Synthetic Biological Membrane project.

  14. 78 FR 22269 - International Conference on Harmonisation; Draft Guidance on M7 Assessment and Control of DNA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... M7 Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals To Limit... ``M7 Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit... and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential...

  15. Precise, motion-free polarization control in Second Harmonic Generation microscopy using a liquid crystal modulator in the infinity space.

    PubMed

    Lien, Chi-Hsiang; Tilbury, Karissa; Chen, Shean-Jen; Campagnola, Paul J

    2013-01-01

    Second Harmonic Generation (SHG) microscopy coupled with polarization analysis has great potential for use in tissue characterization, as molecular and supramolecular structural details can be extracted. Such measurements are difficult to perform quickly and accurately. Here we present a new method that uses a liquid crystal modulator (LCM) located in the infinity space of a SHG laser scanning microscope that allows the generation of any desired linear or circular polarization state. As the device contains no moving parts, polarization can be rotated accurately and faster than by manual or motorized control. The performance in terms of polarization purity was validated using Stokes vector polarimetry, and found to have minimal residual polarization ellipticity. SHG polarization imaging characteristics were validated against well-characterized specimens having cylindrical and/or linear symmetries. The LCM has a small footprint and can be implemented easily in any standard microscope and is cost effective relative to other technologies.

  16. Photonic generation of microwave frequency shift keying signal using a single-drive Mach-Zehnder modulator.

    PubMed

    Cao, Pan; Hu, Xiaofeng; Zhang, Liang; Wu, Jiayang; Jiang, Xinhong; Su, Yikai

    2014-06-16

    We propose and experimentally demonstrate a new scheme for photonic generation of microwave frequency shift keying (FSK) signal by employing one single-drive Mach-Zehnder modulator (MZM). In the proposed method, an electrical signal with different radio frequency (RF) amplitudes and direct current (DC) components for bit '0' and bit '1' is generated. After amplification, the signal is fed into a single-drive MZM which is biased at the quadrature and null points of its transmission curve for bit '0' and bit '1', respectively. Due to the different RF amplitudes, a microwave FSK signal can be obtained after photodetection, where the space frequency is the same as the RF frequency and the mark frequency is twice as large as the RF frequency. The feasibility of the proposed scheme is verified by a proof-of-concept experiment. 5/10-GHz and 10/20-GHz microwave FSK signals with different bit rates are successfully demonstrated.

  17. Walk-Off-Induced Modulation Instability, Temporal Pattern Formation, and Frequency Comb Generation in Cavity-Enhanced Second-Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Leo, F.; Hansson, T.; Ricciardi, I.; De Rosa, M.; Coen, S.; Wabnitz, S.; Erkintalo, M.

    2016-01-01

    We derive a time-domain mean-field equation to model the full temporal and spectral dynamics of light in singly resonant cavity-enhanced second-harmonic generation systems. We show that the temporal walk-off between the fundamental and the second-harmonic fields plays a decisive role under realistic conditions, giving rise to rich, previously unidentified nonlinear behavior. Through linear stability analysis and numerical simulations, we discover a new kind of quadratic modulation instability which leads to the formation of optical frequency combs and associated time-domain dissipative structures. Our numerical simulations show excellent agreement with recent experimental observations of frequency combs in quadratic nonlinear media [Phys. Rev. A 91, 063839 (2015)]. Thus, in addition to unveiling a new, experimentally accessible regime of nonlinear dynamics, our work enables predictive modeling of frequency comb generation in cavity-enhanced second-harmonic generation systems. We expect our findings to have wide impact on the study of temporal and spectral dynamics in a diverse range of dispersive, quadratically nonlinear resonators.

  18. Visual working memory modulates low-level saccade target selection: evidence from rapidly generated saccades in the global effect paradigm.

    PubMed

    Hollingworth, Andrew; Matsukura, Michi; Luck, Steven J

    2013-11-04

    In three experiments, we examined the influence of visual working memory (VWM) on the metrics of saccade landing position in a global effect paradigm. Participants executed a saccade to the more eccentric object in an object pair appearing on the horizontal midline, to the left or right of central fixation. While completing the saccade task, participants maintained a color in VWM for an unrelated memory task. Either the color of the saccade target matched the memory color (target match), the color of the distractor matched the memory color (distractor match), or the colors of neither object matched the memory color (no match). In the no-match condition, saccades tended to land at the midpoint between the two objects: the global, or averaging, effect. However, when one of the two objects matched VWM, the distribution of landing position shifted toward the matching object, both for target match and for distractor match. VWM modulation of landing position was observed even for the fastest quartile of saccades, with a mean latency as low as 112 ms. Effects of VWM on such rapidly generated saccades, with latencies in the express-saccade range, indicate that VWM interacts with the initial sweep of visual sensory processing, modulating perceptual input to oculomotor systems and thereby biasing oculomotor selection. As a result, differences in memory match produce effects on landing position similar to the effects generated by differences in physical salience.

  19. An optical millimeter-wave generation scheme based on two parallel dual-parallel Mach-Zehnder modulators and polarization multiplexing

    NASA Astrophysics Data System (ADS)

    Li, Xuan; Zhao, Shanghong; Zhu, Zihang; Gong, Bing; Chu, Xingchun; Li, Yongjun; Zhao, Jing; Liu, Yun

    2015-10-01

    A novel filterless optical millimeter-wave signal generation scheme is proposed. In the scheme, the undesired sidebands are suppressed using two parallel dual-parallel Mach-Zehnder modulators (MZMs) with different modulation indexes and polarization multiplexing, and frequency multiplication factor as high as 16 can be achieved. Simulation results show that 80, 120, and 160 GHz signals are generated through a 10 GHz RF signal using the proposed method, and the performance of the generated signals is good when commercially available MZMs with extinction ratio of 20-30 dB are used. The scheme has large tunability of modulation index for frequency octupling and 12-tupling signals generation and high stability against the RF driving voltage deviation for frequency 16-tupling generation.

  20. Physical modeling of RF source generation based on electro-optic modulation and laser injection locking

    NASA Astrophysics Data System (ADS)

    Shi, Shouyuan; Schneider, Garrett; Prather, Dennis W.

    2014-03-01

    In this paper we present a frequency domain method to model the physical behavior of widely tunable (1-100GHz) and spectrally pure (1Hz linewidth) RF source, generated by down-mixing of two coherent DFB lasers with a desired RF frequency offset. Rate equations that govern master and injection locking laser behavior are used, and linearization process is followed to derive phase and intensity noise responses by carefully examining the components in the system. Various noise sources are incorporated into the model to explore their significance to final system performance. The phase noise, and RF linewidth are simulated to evaluate the system performance of the generated RF sources.

  1. 18. PWD Drawing 1123915 (814M7) (1945), 'Machinery Cleaning Bldg., Bldg ...

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

    18. PWD Drawing 11239-15 (814-M-7) (1945), 'Machinery Cleaning Bldg., Bldg No. 814, Fire Protection Automatic CO2 and Tank Cover Control' - Mare Island Naval Shipyard, Chemical Cleaning Facility, North of Fourteenth Street, between California & Railroad Avenue, Vallejo, Solano County, CA

  2. CATS-ISS_L1B_N-M7.1-V2-07

    Atmospheric Science Data Center

    2016-10-24

    CATS-ISS_L1B_N-M7.1-V2-07 The Cloud-Aerosol Transport System (CATS) is a three wavelength, polarization-sensitive ... Injection Heights Cloud Vertical Extent Aerosol Vertical Extent Volume Depolarization Ratio Profiles Attenuated ...

  3. CATS-ISS_L1B_D-M7.1-V2-07

    Atmospheric Science Data Center

    2016-10-25

    CATS-ISS_L1B_D-M7.1-V2-07 The Cloud-Aerosol Transport System (CATS) is a three wavelength, polarization-sensitive ... Injection Heights Cloud Vertical Extent Aerosol Vertical Extent Volume Depolarization Ratio Profiles Attenuated ...

  4. CATS-ISS_L1B_N-M7.2-V2-07

    Atmospheric Science Data Center

    2016-10-24

    CATS-ISS_L1B_N-M7.2-V2-07 The Cloud-Aerosol Transport System (CATS) is a three wavelength, polarization-sensitive lidar that provides ... in the Earth's atmosphere. Project Title:  CATS Discipline:  Clouds Aerosols Version:  ...

  5. CATS-ISS_L1B_D-M7.2-V2-07

    Atmospheric Science Data Center

    2016-10-24

    CATS-ISS_L1B_D-M7.2-V2-07 The Cloud-Aerosol Transport System (CATS) is a three wavelength, polarization-sensitive lidar that provides ... in the Earth's atmosphere. Project Title:  CATS Discipline:  Clouds Aerosols Version:  ...

  6. CATS-ISS_L1B_D-M7.2-V2-05

    Atmospheric Science Data Center

    2016-05-03

    CATS-ISS_L1B_D-M7.2-V2-05 The Cloud-Aerosol Transport System (CATS) is a three wavelength, polarization-sensitive lidar that provides ... in the Earth's atmosphere. Project Title:  CATS Discipline:  Clouds Aerosols Version:  ...

  7. Next Generation IGBT Switch Plate Development for the SNS High Voltage Converter Modulator

    SciTech Connect

    Kemp, Mark A.; Burkhart, Craig; Nguyen, Minh N.; Anderson, David E.; /Oak Ridge

    2008-09-18

    The RF source High Voltage Converter Modulator (HVCM) systems installed on the Spallation Neutron Source (SNS) have operated well in excess of 200,000 hours, during which time numerous failures have occurred. An improved Insulated Gate Bipolar Transistor (IGBT) switch plate is under development to help mitigate these failures. The new design incorporates two significant improvements. The IGBTs are upgraded to 4500 V, 1200 A, press-pack devices, which increase the voltage margin, facilitate better cooling, and eliminate explosive disassembly of the package in the event of device failure. The upgrade to an advanced IGBT gate drive circuit decreases switching losses and improves fault-condition response. The upgrade design and development status will be presented.

  8. Operation of a Third Generation JPL Electronic Nose in the Regenerative ECLSS Module Simulator at MSFC

    NASA Technical Reports Server (NTRS)

    Ryan, M. A.; Shevade, A. V.; Manatt, K. S.; Haines, B. E.; Perry, J. L.; Roman, M. C.; Scott, J. P.; Frederick, K. R.

    2010-01-01

    An electronic nose has been developed at the Jet Propulsion Laboratory (JPL) to monitor spacecraft cabin air for anomalous events such as leaks and spills of solvents, coolants or other fluids with near-real-time analysis. It is designed to operate in the environment of the US Lab on ISS and was deployed on the International Space Station for a seven-month experiment in 2008-2009. In order improve understanding of ENose response to crew activities, an ENose was installed in the Regenerative ECLSS Module Simulator (REMS) at Marshall Space Flight Center (MSFC) for several months. The REMS chamber is operated with continuous analysis of the air for presence and concentration of CO, CO2, ethane, ethanol and methane. ENose responses were analyzed and correlated with logged activities and air analyses in the REMS.

  9. Design, fabrication, test, qualification and price analysis for third generation design solar cell modules

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An updated program plan is presented showing the task descriptions depicting the work, progress, achievements, and the cause of any deviations from the original plan (SC-1), and how this impacted on the original schedule of the program. In addition there is an update documenting all design alterations made during the pre-production phase and a complete up to date set of engineering and manufacturing documentation (CM-1). The purpose of the work in the original plan was to explore, design, develop, test, and deliver 1000 watts of prototype flat plate, photovoltaic modules appropriate for use in applications in the 20 to 500 kilowatt range and which show potential for meeting the 1986 cost goals.

  10. A high-resolution fiber optic accelerometer based on intracavity phase-generated carrier (PGC) modulation

    NASA Astrophysics Data System (ADS)

    Lin, Qiao; Chen, Liuhua; Li, Shu; Wu, X.

    2011-01-01

    A compact-size fiber optic accelerometer was designed to achieve both high resolution and wide dynamic range concurrently. An optical cavity, with its length modulated by a piezoelectric oscillator at audio frequency, is utilized to resolve the nanometer-level displacement of a silicon micro-mirror which serves as an inertial mass for acceleration sensing. Strain analysis of the proof-mass flexure structure by Cosmosworks was carried out to calculate responsivity and resonance frequency for a comparison with experimental measurement. The responsivity below the structural resonance frequency of 160 Hz reaches 36 dB re 1 rad/g. Performance measurement demonstrated that the accelerometer was able to resolve an acceleration of 48 ng Hz-1/2 with a dynamic range of 2 × 107.

  11. Cysteine-Generated Sulfide in the Cytosol Negatively Regulates Autophagy and Modulates the Transcriptional Profile in Arabidopsis[W

    PubMed Central

    Álvarez, Consolación; García, Irene; Moreno, Inmaculada; Pérez-Pérez, María Esther; Crespo, José L.; Romero, Luis C.; Gotor, Cecilia

    2012-01-01

    In Arabidopsis thaliana, DES1 is the only identified l-Cysteine desulfhydrase located in the cytosol, and it is involved in the degradation of cysteine and the concomitant production of H2S in this cell compartment. Detailed characterization of the T-DNA insertion mutants des1-1 and des1-2 has provided insight into the role of sulfide metabolically generated in the cytosol as a signaling molecule. Mutations of L-CYS DESULFHYDRASE 1 (DES1) impede H2S generation in the Arabidopsis cytosol and strongly affect plant metabolism. Senescence-associated vacuoles are detected in mesophyll protoplasts of des1 mutants. Additionally, DES1 deficiency promotes the accumulation and lipidation of the ATG8 protein, which is associated with the process of autophagy. The transcriptional profile of the des1-1 mutant corresponds to its premature senescence and autophagy-induction phenotypes, and restoring H2S generation has been shown to eliminate the phenotypic defects of des1 mutants. Moreover, sulfide is able to reverse ATG8 accumulation and lipidation, even in wild-type plants when autophagy is induced by carbon starvation, suggesting a general effect of sulfide on autophagy regulation that is unrelated to sulfur or nitrogen limitation stress. Our results suggest that cysteine-generated sulfide in the cytosol negatively regulates autophagy and modulates the transcriptional profile of Arabidopsis. PMID:23144183

  12. The actin crosslinking protein palladin modulates force generation and mechanosensitivity of tumor associated fibroblasts

    PubMed Central

    Azatov, Mikheil; Goicoechea, Silvia M.; Otey, Carol A.; Upadhyaya, Arpita

    2016-01-01

    Cells organize actin filaments into higher-order structures by regulating the composition, distribution and concentration of actin crosslinkers. Palladin is an actin crosslinker found in the lamellar actin network and stress fibers, which are critical for mechanosensing of the environment. Palladin also serves as a molecular scaffold for α-actinin, another key actin crosslinker. By virtue of its close interactions with actomyosin structures in the cell, palladin may play an important role in cell mechanics. However, the role of palladin in cellular force generation and mechanosensing has not been studied. Here, we investigate the role of palladin in regulating the plasticity of the actin cytoskeleton and cellular force generation in response to alterations in substrate stiffness. Traction force microscopy revealed that tumor-associated fibroblasts generate larger forces on substrates of increased stiffness. Contrary to expectations, knocking down palladin increased the forces generated by cells and inhibited their ability to sense substrate stiffness for very stiff gels. This was accompanied by significant differences in actin organization, adhesion dynamics and altered myosin organization in palladin knock-down cells. Our results suggest that actin crosslinkers such as palladin and myosin motors coordinate for optimal cell function and to prevent aberrant behavior as in cancer metastasis. PMID:27353427

  13. MODULATING EMISSIONS FROM ELECTRIC GENERATING UNITS AS A FUNCTION OF METEOROLOGICAL VARIABLES

    EPA Science Inventory

    Electric Generating Units (EGUs) are an important source of emissions of nitrogen oxides (NOx), which react with volatile organic compounds (VOCs) in the presence of sunlight to form ozone. Emissions from EGUs are believed to vary depending on short-term demands for electricity;...

  14. GPS-Observed Displacements for the M7.7 October 27, 2012, Haida Gwaii Earthquake

    NASA Astrophysics Data System (ADS)

    Nykolaishen, L.; Dragert, H.; Wang, K.; Schmidt, M.; Lu, Y.; Schofield, B.

    2013-12-01

    On October 27, 2012, Canada's second largest (M7.7) instrumentally-recorded earthquake occurred off the west coast of southern Haida Gwaii. Unlike the 1949 M8.1 earthquake on the Queen Charlotte Fault, which involved characteristic strike-slip motion between the Pacific and North America plates, this earthquake involved low-angle thrust almost perpendicular to the coastal margin and generated large tsunami waves on the local coast. Here, the age of the underthrusting Pacific plate is only about 8 Ma, similar to that of the subducting Juan de Fuca plate along the Cascadia subduction zone, resulting in a very warm thermal environment. As a shallow rupture along a 'warm megathrust', the Haida Gwaii event can be viewed as a small-scale analogy of a great Cascadia earthquake. To refine regional source models, we investigate the associated co- and post-seismic displacements using a small, high precision GPS network installed in the weeks following the event. Co-seismic offsets at four re-occupied stations were estimated using historical data sets, with pre-earthquake positions determined by extrapolating linear velocities derived from earlier repeated campaigns. Preliminary results indicate movement at the coastal station closest (~30 km) to the epicentre of 1.2 m to the SSW, with 30 cm of subsidence. Operated by the Province of British Columbia, the only continuously recording station on Haida Gwaii, ~80 km from the epicentre, provided a more robust co-seismic estimate of 23 cm to the SSW. To date, estimates of cumulative post-seismic displacements from seven sites indicate up to 4 cm of motion, with a systematic along-strike variation in azimuthal directions between SSW and SE. The co-seismic results are consistent with a shallow-dipping thrust rupture underlying the Queen Charlotte Terrace which is located immediately seaward of the Queen Charlotte Fault; however, the observed horizontal and vertical displacements are not fully explained by rupture models based on

  15. A Low-Cost 16 Quadrature Amplitude Modulation Direct-Detection-Orthogonal Frequency-Division Multiplexing Radio-over-Fiber System Using Low-Cost Direct-Modulation Laser to Generate Optical mm-Wave

    NASA Astrophysics Data System (ADS)

    Nguyen, HoangViet

    2015-07-01

    This article demonstrates a novel scheme to generate 16 quadrature amplitude modulation orthogonal frequency-division multiplexing signals for radio-over-fiber systems using a low-cost direct-modulation laser to generate an optical millimeter-wave. Mathematical analysis of that system is also investigated. The fiber Bragg grating is employed because the repetitive frequency of the radio frequency source and the bandwidth of the optical modulator are largely reduced, and the architecture of the radio-over-fiber system is simpler. Because no expensive broadband external modulator is used, the overall system is considered a low-cost solution. The simple structure and low cost of the radio-over-fiber system is attractive for the future cost-effective systems.

  16. Demonstration of high-speed quadrature phase shift keying vector signal generation employing a single Mach-Zehnder modulator with phase precoding technology

    NASA Astrophysics Data System (ADS)

    Wang, Yanyi; Li, Xinying; Yu, Jianjun

    2016-01-01

    We numerically and experimentally investigate high-speed quadrature phase shift keying (QPSK) vector signal generation based on a single Mach-Zehnder intensity modulator employing a precoding technique. We experimentally demonstrate 16-Gbaud QPSK vector signal generation at 16-GHz carrier adopting optical carrier suppression with precoding technique, and it is the highest baud rate generated by this technology. The 16-Gbaud QPSK modulated vector signal is delivered over a 20-km large effective area fiber or 2-km single-mode fiber with a bit-error-rate less than the hard-decision forward-error-correction threshold of 3.8×10-3.

  17. Analysis of frequency quadrupling using a single Mach-Zehnder modulator for millimeter-wave generation and distribution over fiber systems.

    PubMed

    Mohamed, Mohmoud; Zhang, Xiupu; Hraimel, Bouchaib; Wu, Ke

    2008-07-01

    We comprehensively investigate three modulation techniques for the generation of millimeter-wave (mm-wave) using optical frequency quadrupling with a dual???electrode Mach-Zehnder modulator (MZM), i.e. Technique-A, Technique-B and Technique-C. For Technique-A, an RF signal drives the two electrodes of the MZM with maximum transmission bias, and this MZM is used for both the mm-wave generation and signal modulation. Technique-B is the same as Technique-A, but 180(0) phase shift between the two electrodes is applied. Technique-C is the same as Technique-B, but the MZM is only used for the mm-wave generation without signal modulation. It is found that Technique-B and Technique-C are better for frequency quadrupling than frequency doubling, tripling and sextupling. Both theoretical analysis and simulation show that the generated mm-wave suffers from constructive/destructive interaction due to fiber chromatic dispersion in Technique-A. However, the generated mm-wave is almost robust to fiber chromatic dispersion in Technique-B and Technique- C. It is found that Technique-C is the best in the quality of the generated mm-wave, especially when poor optical filtering is used. In addition, we develop a theory for calculation of Q-factor for mm-wave generation using the three modulation techniques. We consider an RF at 7.5 GHz and obtain an mm-wave at 30 GHz as an example, i.e. a frequency quadrupler. We evaluate the generation and distribution in terms of system Q-factor. The impact of RF modulation index, chromatic dispersion, MZM extinction ratio and optical filtering on Q-factor are investigated.

  18. Construction and use of an ipb DNA module to generate Pseudomonas strains with constitutive trichloroethene and isopropylbenzene oxidation activity

    SciTech Connect

    Berendes, F.; Sabarth, N.; Averhoff, B.; Gottschalk, G.

    1998-07-01

    Pseudomonas sp. strain JR1 exhibits trichloroethene (TCE) oxidation activity with isopropylbenzene (IPB) as the inducer substrate. The authors previously reported the genes encoding the first three enzymes of the IPB-deg-radiative pathway (ipbAl, ipbA2, ipbA3, ipbA4, ipbB, and ipbC) an identified the initial IPB dioxygenase (IpbAlA2A3A4) as responsible for TCE cooxidation. Primer extension analyses revealed multiple transcriptional start points located upstream of the translational initiation codon of ipbA1. The transcription from these start sites was found to be IPB dependent. Thirty-one base pairs upstream of the first transcriptional start point tandemly repeated DNA sequences overlapping the {minus}35 region of a putative {sigma}{sup 70} promoter were found. These repeats exhibit significant sequence3 similarity to the operator-promoter region of the xyl meta operon in Pseudomonas putida, which is required for the binding of XylS, a regulatory protein of the XylS (also called AraC) family. These similarities suggest that the transcription of the IPB dioxygenase genes is modulated by a regulatory protein of the XylS/AraC family. The construction of an ipb DNA module devoid of this ipb operator-promoter region and the stable insertion of this DNA module into the genomes of different Pseudomonas strains resulted in pseudomonads with constitutive IPB and TCE oxidation activities. Constitutive TCE oxidation of two such Pseudomonas hybrid strains, JR1A::ipb and CBS-3::ipb, was found to be stable for more than 120 generations in antibiotic-free medium. Evaluation of constitutive TCE degradation rates revealed that continuous cultivation of strain JR1A::ipb resulted in a significant increase in rates of TCE degradation.

  19. Evidence for opioid modulation and generation of prostaglandins in sulphur dioxide (SO)2-induced bronchoconstriction.

    PubMed Central

    Field, P. I.; Simmul, R.; Bell, S. C.; Allen, D. H.; Berend, N.

    1996-01-01

    BACKGROUND: Inhalation of sulphur dioxide (SO2) provokes bronchoconstriction in asthmatic subjects. Cholinergic mechanisms contribute, but other mechanisms remain undefined. The effect of morphine, an opioid agonist, on the cholinergic component of SO2-induced bronchoconstriction was investigated, and the effect of indomethacin, a cyclooxygenase inhibitor, on SO2-induced bronchoconstriction and tachyphylaxis was studied. METHODS: In the first study 16 asthmatic subjects inhaled either ipratropium bromide or placebo 60 minutes before an SO2 challenge on days 1 and 2. On day 3 an SO2 challenge was performed immediately after intravenous morphine. In the second study 15 asthmatic subjects took either placebo or indomethacin for three days before each study day when two SO2 challenges were performed 30 minutes apart. The response was measured as the cumulative dose causing a 35% fall in specific airways conductance (sGaw; PDsGaw35). RESULTS: Ipratropium bromide significantly inhibited SO2 responsiveness, reducing PDsGaw35 by 0.89 (95% CI 0.46 to 1.31) doubling doses. This effect persisted after correction for bronchodilatation induced by ipratropium bromide. The effect of ipratropium bromide and morphine on SO2 responsiveness also correlated (r2 = 0.71). In the second study SO2 tachyphylaxis developed with PDsGaw35 on repeated testing, being reduced by 0.62 (95% CI 0.17 to 1.07) doubling doses. Indomethacin attenuated baseline SO2 responsiveness, increasing PDsGaw35 by 0.5 (95% CI 0.06 to 0.93) doubling doses. CONCLUSIONS: These results suggest that opioids modulate the cholinergic component of SO2 responsiveness and that cyclooxygenase products contribute to the immediate response to SO2. PMID:8711648

  20. Optical Tweezers Array and Nimble Tweezers Probe Generated by Spatial- Light Modulator

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.; Jassemnejad, Baha; Seibel, Robin E.; Weiland, Kenneth E.

    2003-01-01

    An optical tweezers is being developed at the NASA Glenn Research Center as a visiblelight interface between ubiquitous laser technologies and the interrogation, visualization, manufacture, control, and energization of nanostructures such as silicon carbide (SiC) nanotubes. The tweezers uses one or more focused laser beams to hold micrometer-sized particles called tools (sometimes called tips in atomic-force-microscope terminology). A strongly focused laser beam has an associated light-pressure gradient that is strong enough to pull small particles to the focus, in spite of the oppositely directed scattering force; "optical tweezers" is the common term for this effect. The objective is to use the tools to create carefully shaped secondary traps to hold and assemble nanostructures that may contain from tens to hundreds of atoms. The interaction between a tool and the nanostructures is to be monitored optically as is done with scanning probe microscopes. One of the initial efforts has been to create, shape, and control multiple tweezers beams. To this end, a programmable spatial-light modulator (SLM) has been used to modify the phase of a laser beam at up to 480 by 480 points. One program creates multiple, independently controllable tweezer beams whose shapes can be tailored by making the SLM an adaptive mirror in an interferometer (ref. 1). The beams leave the SLM at different angles, and an optical Fourier transform maps these beams to different positions in the focal plane of a microscope objective. The following figure shows two arrays of multiple beams created in this manner. The patterns displayed above the beam array control the intensity-to-phase transformation required in programming the SLM. Three of the seven beams displayed can be used as independently controllable beams.

  1. Cyclic AMP Signaling through Epac Axis Modulates Human Hemogenic Endothelium and Enhances Hematopoietic Cell Generation.

    PubMed

    Saxena, Shobhit; Rönn, Roger E; Guibentif, Carolina; Moraghebi, Roksana; Woods, Niels-Bjarne

    2016-05-10

    Hematopoietic cells emerge from hemogenic endothelium in the developing embryo. Mechanisms behind human hematopoietic stem and progenitor cell development remain unclear. Using a human pluripotent stem cell differentiation model, we report that cyclic AMP (cAMP) induction dramatically increases HSC-like cell frequencies. We show that hematopoietic cell generation requires cAMP signaling through the Exchange proteins activated by cAMP (cAMP-Epac) axis; Epac signaling inhibition decreased both hemogenic and non-hemogenic endothelium, and abrogated hematopoietic cell generation. Furthermore, in hematopoietic progenitor and stem-like cells, cAMP induction mitigated oxidative stress, created a redox-state balance, and enhanced C-X-C chemokine receptor type 4 (CXCR4) expression, benefiting the maintenance of these primitive cells. Collectively, our study provides insights and mechanistic details on the previously unrecognized role of cAMP signaling in regulating human hematopoietic development. These findings advance the mechanistic understanding of hematopoietic development toward the development of transplantable human hematopoietic cells for therapeutic needs. PMID:27117782

  2. Generation of self-induced-transparency gap solitons by modulational instability in uniformly doped fiber Bragg gratings

    SciTech Connect

    Kalithasan, B.; Porsezian, K.; Senthilnathan, K.; Tchofo Dinda, P.

    2010-05-15

    We consider the continuous-wave (cw) propagation through a fiber Bragg grating that is uniformly doped with two-level resonant atoms. Wave propagation is governed by a system of nonlinear coupled-mode Maxwell-Bloch (NLCM-MB) equations. We identify modulational instability (MI) conditions required for the generation of ultrashort pulses in both anomalous and normal dispersion regimes. From a detailed linear stability analysis, we find that the atomic detuning frequency has a strong influence on the MI. That is, the atomic detuning frequency induces nonconventional MI sidebands at the photonic band gap (PBG) edges and near the PBG edges. Especially in the normal dispersion regime, MI occurs without any threshold condition, which is in contrast with that of conventional fiber Bragg gratings. We also perform a numerical analysis to solve the NLCM-MB equations. The numerical results of the prediction of both the optimum modulation wave number and the optimum gain agree well with that of the linear stability analysis. Another main result of the present work is the prediction of the existence of both bright and dark self-induced transparency gap solitons at the PBG edges.

  3. PPAR modulators and PPAR pan agonists for metabolic diseases: the next generation of drugs targeting peroxisome proliferator-activated receptors?

    PubMed

    Feldman, P L; Lambert, M H; Henke, B R

    2008-01-01

    The Peroxisome Proliferator-Activated Receptors-PPAR alpha, PPAR gamma, and PPAR delta--are members of the nuclear receptor gene family that have emerged as therapeutic targets for the development of drugs to treat human metabolic diseases. The discovery of high affinity, subtype-selective agonists for each of the three PPAR subtypes has allowed elucidation of the pharmacology of these receptors and development of first-generation therapeutic agents for the treatment of diabetes and dyslipidemia. However, despite proven therapeutic benefits of selective PPAR agonists, safety concerns and dose-limiting side effects have been observed, and a number of late-stage development failures have been reported. Scientists have continued to explore ligand-based activation of PPARs in hopes of developing safer and more effective drugs. This review highlights recent efforts on two newer approaches, the simultaneous activation of all three PPAR receptors with a single ligand (PPAR pan agonists) and the selective modulation of a single PPAR receptor in a cell or tissue specific manner (selective PPAR modulator or SPPARM) in order to induce a subset of target genes and affect a restricted number of metabolic pathways. PMID:18537685

  4. On the Use of Thermoelectric (TE) Applications Based on Commercial Modules: The Case of TE Generator and TE Cooler

    NASA Astrophysics Data System (ADS)

    Zorbas, K.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kyratsi, Th.

    2010-01-01

    In recent years, thermoelectricity sees rapidly increasing usages in applications like portable refrigerators, beverage coolers, electronic component coolers etc. when used as Thermoelectric Cooler (TEC), and Thermoelectric Generators (TEG) which make use of the Seebeck effect in semiconductors for the direct conversion of heat into electrical energy and is of particular interest for systems of highest reliability or for waste heat recovery. In this work, we examine the performance of commercially available TEC and TEG. A prototype TEC-refrigerator has been designed, modeled and constructed for in-car applications. Additionally, a TEG was made, in order to measure the gained power and efficiency. Furthermore, a TEG module was tested on a small size car (Toyota Starlet, 1300 cc), in order to measure the gained power and efficiency for various engine loads. With the use of a modeling approach, we evaluated the thermal contact resistances and their influence on the final device efficiency.

  5. W-band OFDM photonic vector signal generation employing a single Mach-Zehnder modulator and precoding.

    PubMed

    Xiao, Jiangnan; Li, Xinying; Xu, Yuming; Zhang, Ziran; Chen, Long; Yu, Jianjun

    2015-09-01

    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.

  6. Relativistically intense plane electromagnetic waves in electron-positron plasmas: Nonlinear self-modulation and harmonics generation regimes

    SciTech Connect

    Shiryaev, O. B.

    2006-11-15

    A fully nonlinear one-dimensional problem describing the interactions of relativistically intense plane electromagnetic waves and cold locally non-neutral electron-positron plasmas is derived from Maxwell and fluid dynamics equations. Numerical and asymptotic solutions to this problem for phase velocities close to the speed of light are presented. Depending on the magnitude of the plasma longitudinal electric-field potential, the system considered is found to support two distinct regimes of plane electromagnetic wave propagation: a nonlinear self-modulation one with the coupling of a fast transversely polarized electromagnetic field to a slow longitudinal plasma field, and a harmonics generation one with both of these fields oscillating with comparable frequencies. In the former case, a splitting of the electromagnetic field spectrum into a series of closely located bands occurs, whereas in the latter one the propagating field spectrum is a set of radiation harmonics.

  7. Optical generation of a spatially variant two-dimensional lattice structure by using a phase only spatial light modulator

    SciTech Connect

    Kumar, Manish Joseph, Joby

    2014-08-04

    We propose a simple and straightforward method to generate spatially variant lattice structures by optical interference lithography method. Using this method, it is possible to independently vary the orientation and period of the two-dimensional lattice. The method consists of two steps which are: numerical synthesis of corresponding phase mask by employing a two-dimensional integrated gradient calculations and experimental implementation of synthesized phase mask by making use of a phase only spatial light modulator in an optical 4f Fourier filtering setup. As a working example, we provide the experimental fabrication of a spatially variant square lattice structure which has the possibility to guide a Gaussian beam through a 90° bend by photonic crystal self-collimation phenomena. The method is digitally reconfigurable, is completely scalable, and could be extended to other kind of lattices as well.

  8. Disaccharides generated from heparan sulphate or heparin modulate chemokine-induced T-cell adhesion to extracellular matrix.

    PubMed

    Hershkoviz, R; Schor, H; Ariel, A; Hecht, I; Cohen, I R; Lider, O; Cahalon, L

    2000-01-01

    We have found previously that disaccharides (DS) enzymatically generated from heparin or heparan sulphate can modulate tumour necrosis factor-alpha (TNF-alpha) secretion from immune cells in vitro and cell-mediated immune reactions in vivo. Here, we show that such DS can modulate the adhesion and migration of human T cells. We found that certain heparin- and heparan sulphate-derived DS induced, in a dose-dependent manner, the adhesion of human T cells to both extracellular matrix (ECM) and immobilized fibronectin (FN); maximal T-cell adhesion occurred with 1 ng/ml of DS. The levels of T-cell adhesion to ECM that were induced by the tested DS molecules resembled those induced by the prototypic chemokine, macrophage inflammatory protein 1beta (MIP-1beta). However, the kinetics of DS-induced T-cell adhesion to FN resembled that induced by phorbol myristate acetate (PMA), but not that induced by MIP-1beta. This adhesion appeared to involve beta1 integrin recognition and activation, and was associated with specific intracellular activation pathways. Although a first exposure of T cells to certain DS molecules appeared to result in cell adhesion, a subsequent exposure of T cells to pro-adhesive chemokines, such as MIP-1beta or RANTES, but not to other pro-adhesive stimuli, for example interleukin-2 or CD3 cross-linking, resulted in inhibition of T-cell adhesion to and chemotactic migration through FN. Hence, we propose that the breakdown products of tissues generated by inflammatory enzymes are part of an intrinsic functional programme, and not necessarily molecular waste. Moreover, because the DS molecules exert their modulatory functions within a limited time, it appears that the historical encounters of the tissue-invading cells with the constituents of inflamed loci may dictate the cells' behaviour upon subsequent exposure to proinflammatory mediators. PMID:10651945

  9. Wave-front phase-modulation control and focusing of second-harmonic light generated in transparent nonlinear random structures

    NASA Astrophysics Data System (ADS)

    Yao, Can; Rodriguez, Francisco J.; Bravo-Abad, Jorge; Martorell, Jordi

    2013-06-01

    We theoretically investigate how phase-only spatial light modulation can enable controlling and focusing the second-harmonic light generated in transparent nonlinear random structures. The studied structures are composed of domains with random sizes and antiparallel polarization, which accurately model widely used ferroelectric crystals such as strontium barium niobate. Using a first-principles Green-function formalism, we account for the effect that spatial light modulation of the fundamental beam introduces into the second-order nonlinear frequency conversion occurring in the considered class of structures. This approach provides a complete description of the physical origin of the second-harmonic light generation in the system, as well as the optimization of the light intensity in any arbitrary direction. Our numerical results show how the second-harmonic light is influenced by both the disorder in the structure and the boundaries of the crystal. Particularly, we find that the net result from the interplay between disorder and boundary effects is strongly dependent on the dimensions of the crystal and the observation direction. Remarkably, our calculations also show that although in general the maximum possible enhancement of the second-order light is the same as the one corresponding to linear light scattering in turbid media, in the Cerenkov phase matching direction the enhancement can exceed the linear limit. The theoretical analysis presented in this work expands the current understanding of light control in complex media and could contribute to the development of a new class of imaging and focusing techniques based on nonlinear frequency mixing in random optical materials.

  10. Au nanorods modulated NIR fluorescence and singlet oxygen generation of water soluble dendritic zinc phthalocyanine.

    PubMed

    Zhou, Xuefei; He, Xiaohong; Wei, Shiliang; Jia, Kun; Liu, Xiaobo

    2016-11-15

    A novel cyano-terminated zinc phthalocyanine (ZnPc-CN) exhibiting visible near infrared (vis-NIR) emitting around 690nm in N,N-dimethylformamide (DMF) solvent has been synthesized. Furthermore, the peripheral cyano groups of newly synthesized zinc phthalocyanine were hydrolyzed in strong basic solution, leading to water soluble carboxylated zinc phthalocyanine (ZnPc-COOH) with completely quenched fluorescence in aqueous solution. Interestingly, we found that the NIR fluorescence of aqueous ZnPc-COOH was dramatically recovered in the presence of gold nanorods (Au NR), which was due to the alternation of ZnPc-COOH molecules self-assembling via electrostatic interaction between cetyltrimethylammonium bromide (CTAB) on the surface of Au NR and peripheral carboxyl of ZnPc-COOH. In addition, ZnPc-COOH/Au NR conjugates demonstrated an improved singlet oxygen generation, which could be served as potential bioimaging probe and photosensitizer for photodynamic therapy. PMID:27505278

  11. L-Cysteine Desulfhydrase 1 modulates the generation of the signaling molecule sulfide in plant cytosol

    PubMed Central

    Romero, Luis C.; García, Irene; Gotor, Cecilia

    2013-01-01

    Consistent with data in animal systems, experimental evidence highlights sulfide as a signaling molecule of equal importance to NO and H2O2 in plant systems. In mammals, two cytosolic enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), have been shown to be responsible for the endogenous production of sulfide. L-cysteine desulfhydrase 1 (DES1) has been recently established as the only enzyme that is involved in the generation of hydrogen sulfide in plant cytosol. Although plants have an available source of sulfide within chloroplasts, the basic stromal pH prevents sulfide release into the cytosol. Therefore, DES1 is essential for the production of sulfide for signaling purposes. PMID:23428891

  12. Predictability of Great Earthquakes: The 25 April 2015 M7.9 Gorkha (Nepal)

    NASA Astrophysics Data System (ADS)

    Kossobokov, V. G.

    2015-12-01

    Understanding of seismic process in terms of non-linear dynamics of a hierarchical system of blocks-and-faults and deterministic chaos, has already led to reproducible intermediate-term middle-range prediction of the great and significant earthquakes. The technique based on monitoring charcteristics of seismic static in an area proportional to source size of incipient earthquake is confirmed at the confidence level above 99% by statistics of Global Testing in forward application from 1992 to the present. The semi-annual predictions determined for the next half-year by the algorithm M8 aimed (i) at magnitude 8+ earthquakes in 262 circles of investigation, CI's, each of 667-km radius and (ii) at magnitude 7.5+ earthquakes in 180 CI's, each of 427-km radius are communicated each January and July to the Global Test Observers (about 150 today). The pre-fixed location of CI's cover all seismic regions where the M8 algorithm could run in its original version that requires annual rate of activity of 16 or more main shocks. According to predictions released in January 2015 for the first half of 2015, the 25 April 2015 Nepal MwGCMT = 7.9 earthquake falls outside the Test area for M7.5+, while its epicenter is within the accuracy limits of the alarm area for M8.0+ that spread along 1300 km of Himalayas. We note that (i) the earthquake confirms identification of areas prone to strong earthquakes in Himalayas by pattern recognition (Bhatia et al. 1992) and (ii) it would have been predicted by the modified version of the M8 algorithm aimed at M7.5+. The modified version is adjusted to a low level of earthquake detection, about 10 main shocks per year, and is tested successfully by Mojarab et al. (2015) in application to the recent earthquakes in Eastern Anatolia (23 October 2011, M7.3 Van earthquake) and Iranian Plateau (16 April 2013, M7.7 Saravan and the 24 September 2013, M7.7 Awaran earthquakes).

  13. SVBR-100 module-type fast reactor of the IV generation for regional power industry

    NASA Astrophysics Data System (ADS)

    Zrodnikov, A. V.; Toshinsky, G. I.; Komlev, O. G.; Stepanov, V. S.; Klimov, N. N.

    2011-08-01

    In the report the following is presented: basic conceptual provisions of the innovative nuclear power technology (NPT) based on modular fast reactors (FR) SVBR-100, summarized results of calculations of the reactor, analysis of the opportunities of multi-purpose application of such reactor facilities (RF) including export potentials with due account of nonproliferation requirements. The most important features of the proposed NPT analyzed in the report are as follows: (1) integral (monoblock) arrangement of the primary circuit equipment with entire elimination of the primary circuit pipelines and valves that considerably reduces the construction and assembly works period and coupling with high boiling point of lead-bismuth coolant (LBC) deterministically eliminates accidents of the LOCA type, (2) option for 100 MWe power and dimensions of the reactor provide: on the one hand, an opportunity to transport the reactor monoblock in factory-readiness by railway as well as other kinds of transport, on the other hand, core breeding ratio (CBR) exceeds 1 while MOX-fuel is used. The preferable area of application of RF SVBR-100 is regional and small power requiring power-units of electric power in a range of (100-600) MW, which could be used for cogeneration-based district heating while locating them nearby cities as well as for generation of electric power in a mode of load tracking in the regions with low network systems.

  14. Transferrin receptor regulates pancreatic cancer growth by modulating mitochondrial respiration and ROS generation.

    PubMed

    Jeong, Seung Min; Hwang, Sunsook; Seong, Rho Hyun

    2016-03-11

    The transferrin receptor (TfR1) is upregulated in malignant cells and its expression is associated with cancer progression. Because of its pre-eminent role in cell proliferation, TfR1 has been an important target for the development of cancer therapy. Although TfR1 is highly expressed in pancreatic cancers, what it carries out in these refractory cancers remains poorly understood. Here we report that TfR1 supports mitochondrial respiration and ROS production in human pancreatic ductal adenocarcinoma (PDAC) cells, which is required for their tumorigenic growth. Elevated TfR1 expression in PDAC cells contributes to oxidative phosphorylation, which allows for the generation of ROS. Importantly, mitochondrial-derived ROS are essential for PDAC growth. However, exogenous iron supplement cannot rescue the defects caused by TfR1 knockdown. Moreover, we found that TfR1 expression determines PDAC cells sensitivity to oxidative stress. Together, our findings reveal that TfR1 can contribute to the mitochondrial respiration and ROS production, which have essential roles in growth and survival of pancreatic cancer. PMID:26869514

  15. C-Myc regulation by costimulatory signals modulates the generation of CD8+ memory T cells during viral infection.

    PubMed

    Haque, Mohammad; Song, Jianyong; Fino, Kristin; Wang, Youfei; Sandhu, Praneet; Song, Xinmeng; Norbury, Christopher; Ni, Bing; Fang, Deyu; Salek-Ardakani, Shahram; Song, Jianxun

    2016-01-01

    The signalling mechanisms of costimulation in the development of memory T cells remain to be clarified. Here, we show that the transcription factor c-Myc in CD8(+) T cells is controlled by costimulatory molecules, which modulates the development of memory CD8(+) T cells. C-Myc expression was dramatically reduced in Cd28(-/-) or Ox40(-/-) memory CD8(+) T cells, and c-Myc over-expression substantially reversed the defects in the development of T-cell memory following viral infection. C-Myc regulated the expression of survivin, an inhibitor of apoptosis, which promoted the generation of virus-specific memory CD8(+) T cells. Moreover, over-expression of survivin with bcl-xL, a downstream molecule of NF-κB and intracellular target of costimulation that controls survival, in Cd28(-/-) or Ox40(-/-) CD8(+) T cells, reversed the defects in the generation of memory T cells in response to viral infection. These results identify c-Myc as a key controller of memory CD8(+) T cells from costimulatory signals.

  16. Preclinical evidence supporting the clinical development of central pattern generator-modulating therapies for chronic spinal cord-injured patients

    PubMed Central

    2014-01-01

    Ambulation or walking is one of the main gaits of locomotion. In terrestrial animals, it may be defined as a series of rhythmic and bilaterally coordinated movement of the limbs which creates a forward movement of the body. This applies regardless of the number of limbs—from arthropods with six or more limbs to bipedal primates. These fundamental similarities among species may explain why comparable neural systems and cellular properties have been found, thus far, to control in similar ways locomotor rhythm generation in most animal models. The aim of this article is to provide a comprehensive review of the known structural and functional features associated with central nervous system (CNS) networks that are involved in the control of ambulation and other stereotyped motor patterns—specifically Central Pattern Generators (CPGs) that produce basic rhythmic patterned outputs for locomotion, micturition, ejaculation, and defecation. Although there is compelling evidence of their existence in humans, CPGs have been most studied in reduced models including in vitro isolated preparations, genetically-engineered mice and spinal cord-transected animals. Compared with other structures of the CNS, the spinal cord is generally considered as being well-preserved phylogenetically. As such, most animal models of spinal cord-injured (SCI) should be considered as valuable tools for the development of novel pharmacological strategies aimed at modulating spinal activity and restoring corresponding functions in chronic SCI patients. PMID:24910602

  17. Filterless frequency 12-tupling optical millimeter-wave generation using two cascaded dual-parallel Mach-Zehnder modulators.

    PubMed

    Zhu, Zihang; Zhao, Shanghong; Zheng, Wanze; Wang, Wei; Lin, Baoqin

    2015-11-10

    A novel frequency 12-tupling optical millimeter-wave (mm-wave) generation using two cascaded dual-parallel Mach-Zehnder modulators (DP-MZMs) without an optical filter is proposed and demonstrated by computer simulation. By properly adjusting the amplitude and phase of radio frequency (RF) driving signal and the direct current (DC) bias points of two DP-MZMs, a 120 GHz mm-wave with an optical sideband suppression ratio (OSSR) of 25.1 dB and a radio frequency spurious suppression ratio (RFSSR) of 19.1 dB is shown to be generated from a 10 GHz RF driving signal, which largely reduces the response frequency of electronic devices. Furthermore, it is also proved to be valid that even if the phase difference of RF driving signals, the RF driving voltage, and the DC bias voltage deviate from the ideal values to a certain degree, the performance is still acceptable. Since no optical filter is employed to suppress the undesired optical sidebands, a high-spectral-purity mm-wave signal tunable from 48 to 216 GHz can be obtained theoretically when a RF driving signal from 4 to 18 GHz is applied to the DP-MZMs, and the system can be readily implemented in wavelength-division-multiplexing upconversion systems to provide high-quality optical local oscillator signal.

  18. Ultralow-phase-noise millimetre-wave signal generator assisted with an electro-optics-modulator-based optical frequency comb

    NASA Astrophysics Data System (ADS)

    Ishizawa, A.; Nishikawa, T.; Goto, T.; Hitachi, K.; Sogawa, T.; Gotoh, H.

    2016-05-01

    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).

  19. Ultralow-phase-noise millimetre-wave signal generator assisted with an electro-optics-modulator-based optical frequency comb

    PubMed Central

    Ishizawa, A.; Nishikawa, T.; Goto, T.; Hitachi, K.; Sogawa, T.; Gotoh, H.

    2016-01-01

    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). PMID:27185040

  20. Simulation and Design of Vehicle Exhaust Power Generation Systems: The Interaction Between the Heat Exchanger and the Thermoelectric Modules

    NASA Astrophysics Data System (ADS)

    Tao, Cong; Chen, Gang; Mu, Yu; Liu, Lisheng; Zhai, Pengcheng

    2015-06-01

    Vehicle exhaust power generation systems (VEPGS), mainly consisting of a heat exchanger, cooling system, thermoelectric modules (TEMs), and clamping device, have attracted wide interest and attention for power generation from waste heat. In this work, systematical research was conducted to investigate the thermal performance, power output, and thermal stress of a VEPGS by using the multifield coupling method. Different from previous research, this work simulates a model that integrates the heat exchanger and TEMs, focusing on the effect of the TEMs on the thermal performance of the heat exchanger. It is found that the TEMs have a significant effect on the thermal performance of the heat exchanger. When not considering the effects of the TEMs, the hot-end temperature of the TEMs would be seriously underestimated, which would result in underestimation of the power output of the VEPGS and the level of thermal stress of the TEMs. Meanwhile, when considering the effect of the TEMs, the hot-end temperature distribution exhibits significant changes, and its temperature uniformity is significantly improved. The results suggest that, in VEPGS design and optimization, the interaction between the heat exchanger and TEMs should be considered. This study also contributes to a more accurate assessment method for VEPGS design and simulation.

  1. CB2 cannabinoid receptor is a novel target for third-generation selective estrogen receptor modulators bazedoxifene and lasofoxifene.

    PubMed

    Kumar, Pritesh; Song, Zhao-Hui

    2014-01-01

    The purpose of the current study was to investigate the ability of the third-generation selective estrogen receptor modulators (SERMs) bazedoxifene and lasofoxifene to bind and act on CB2 cannabinoid receptor. We have identified, for the first time, that CB2 is a novel target for bazedoxifene and lasofoxifene. Our results showed that bazedoxifene and lasofoxifene were able to compete for specific [(3)H]CP-55,940 binding to CB2 in a concentration-dependent manner. Our data also demonstrated that by acting on CB2, bazedoxifene and lasofoxifene concentration-dependently enhanced forskolin-stimulated cAMP accumulation. Furthermore, bazedoxifene and lasofoxifene caused parallel, rightward shifts of the CP-55,940, HU-210, and WIN55,212-2 concentration-response curves without altering the efficacy of these cannabinoid agonists on CB2, which indicates that bazedoxifene- and lasofoxifene-induced CB2 antagonism is most likely competitive in nature. Our discovery that CB2 is a novel target for bazedoxifene and lasofoxifene suggests that these third-generation SERMs can potentially be repurposed for novel therapeutic indications for which CB2 is a target. In addition, identifying bazedoxifene and lasofoxifene as CB2 inverse agonists also provides important novel mechanisms of actions to explain the known therapeutic effects of these SERMs. PMID:24275139

  2. C-Myc regulation by costimulatory signals modulates the generation of CD8+ memory T cells during viral infection.

    PubMed

    Haque, Mohammad; Song, Jianyong; Fino, Kristin; Wang, Youfei; Sandhu, Praneet; Song, Xinmeng; Norbury, Christopher; Ni, Bing; Fang, Deyu; Salek-Ardakani, Shahram; Song, Jianxun

    2016-01-01

    The signalling mechanisms of costimulation in the development of memory T cells remain to be clarified. Here, we show that the transcription factor c-Myc in CD8(+) T cells is controlled by costimulatory molecules, which modulates the development of memory CD8(+) T cells. C-Myc expression was dramatically reduced in Cd28(-/-) or Ox40(-/-) memory CD8(+) T cells, and c-Myc over-expression substantially reversed the defects in the development of T-cell memory following viral infection. C-Myc regulated the expression of survivin, an inhibitor of apoptosis, which promoted the generation of virus-specific memory CD8(+) T cells. Moreover, over-expression of survivin with bcl-xL, a downstream molecule of NF-κB and intracellular target of costimulation that controls survival, in Cd28(-/-) or Ox40(-/-) CD8(+) T cells, reversed the defects in the generation of memory T cells in response to viral infection. These results identify c-Myc as a key controller of memory CD8(+) T cells from costimulatory signals. PMID:26791245

  3. C-Myc regulation by costimulatory signals modulates the generation of CD8+ memory T cells during viral infection

    PubMed Central

    Haque, Mohammad; Song, Jianyong; Fino, Kristin; Wang, Youfei; Sandhu, Praneet; Song, Xinmeng; Norbury, Christopher; Ni, Bing; Fang, Deyu; Salek-Ardakani, Shahram; Song, Jianxun

    2016-01-01

    The signalling mechanisms of costimulation in the development of memory T cells remain to be clarified. Here, we show that the transcription factor c-Myc in CD8+ T cells is controlled by costimulatory molecules, which modulates the development of memory CD8+ T cells. C-Myc expression was dramatically reduced in Cd28−/− or Ox40−/− memory CD8+ T cells, and c-Myc over-expression substantially reversed the defects in the development of T-cell memory following viral infection. C-Myc regulated the expression of survivin, an inhibitor of apoptosis, which promoted the generation of virus-specific memory CD8+ T cells. Moreover, over-expression of survivin with bcl-xL, a downstream molecule of NF-κB and intracellular target of costimulation that controls survival, in Cd28−/− or Ox40−/− CD8+ T cells, reversed the defects in the generation of memory T cells in response to viral infection. These results identify c-Myc as a key controller of memory CD8+ T cells from costimulatory signals. PMID:26791245

  4. Ultralow-phase-noise millimetre-wave signal generator assisted with an electro-optics-modulator-based optical frequency comb.

    PubMed

    Ishizawa, A; Nishikawa, T; Goto, T; Hitachi, K; Sogawa, T; Gotoh, H

    2016-01-01

    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). PMID:27185040

  5. Tropospheric aerosol size distributions simulated by three online global aerosol models using the M7 microphysics module

    SciTech Connect

    Zhang, Kai; Wan, Hui; Wang, Bin; Zhang, Meigen; Feichter, J.; Liu, Xiaohong

    2010-07-14

    Tropospheric aerosol size distributions are simulated by three online global models that employ exactly the same modal approach but differ in many aspects such as model meteorology, natural aerosol emissions, sulfur chemistry, and the parameterization of deposition processes. The main purpose of this study is to identify where the largest inter-model discrepancies occur and what the main reasons are. The number concentrations of different aerosol size ranges are compared among the three models and against observations. Overall all the three models can capture the basic features of the observed aerosol number spatial distributions. The magnitude of the number concentration of each mode is consistent among the three models. Quantitative differences are also clearly detectable. For the soluble and insoluble coarse mode and accumulation mode, inter-model discrepancies mainly result from differences in the sea salt and dust emissions, as well as the different strengths of the convective transport in the meteorological models. For the nucleation mode and the soluble Aitken mode, the spread of the model results is largest in the tropics and in the middle and upper troposphere. Diagnostics and sensitivity experiments suggest that this large spread is closely related to the sulfur cycle in the models, which is strongly affected by the choice of sulfur chemistry scheme, its coupling with the convective transport and wet deposition calculation, and the related meteorological fields such as cloud cover, cloud water content, and precipitation. The aerosol size distributions simulated by the three models are compared to observations in the boundary layer. The characteristic shape and magnitude of the distribution functions are reasonably reproduced in typical conditions (i.e., clean, polluted and transition areas). Biases in the mode parameters over the remote oceans and the China adjacent seas are probably caused by the fixed mode variance in the mathematical formulations used in the modal approach in the three models, as well as some of the prescribed size distribution parameters of the natural and anthropogenic emissions.

  6. Complement factor H modulates the activation of human neutrophil granulocytes and the generation of neutrophil extracellular traps.

    PubMed

    Schneider, Andrea E; Sándor, Noémi; Kárpáti, Éva; Józsi, Mihály

    2016-04-01

    Factor H (FH) is a major inhibitor of the alternative pathway of complement activation in plasma and on certain host surfaces. In addition to being a complement regulator, FH can bind to various cells via specific receptors, including binding to neutrophil granulocytes through complement receptor type 3 (CR3; CD11b/CD18), and modulate their function. The cellular roles of FH are, however, poorly understood. Because neutrophils are important innate immune cells in inflammatory processes and the host defense against pathogens, we aimed at studying the effects of FH on various neutrophil functions, including the generation of extracellular traps. FH co-localized with CD11b on the surface of neutrophils isolated from peripheral blood of healthy individuals, and cell-bound FH retained its cofactor activity and enhanced C3b degradation. Soluble FH supported neutrophil migration and immobilized FH induced cell spreading. In addition, immobilized but not soluble FH enhanced IL-8 release from neutrophils. FH alone did not trigger the cells to produce neutrophil extracellular traps (NETs), but NET formation induced by PMA and by fibronectin plus fungal β-glucan were inhibited by immobilized, but not by soluble, FH. Moreover, in parallel with NET formation, immobilized FH also inhibited the production of reactive oxygen species induced by PMA and by fibronectin plus β-glucan. Altogether, these data indicate that FH has multiple regulatory roles on neutrophil functions. While it can support the recruitment of neutrophils, FH may also exert anti-inflammatory effects and influence local inflammatory and antimicrobial reactions, and reduce tissue damage by modulating NET formation. PMID:26938503

  7. Establishing best practise in the application of expert review of mutagenicity under ICH M7.

    PubMed

    Barber, Chris; Amberg, Alexander; Custer, Laura; Dobo, Krista L; Glowienke, Susanne; Van Gompel, Jacky; Gutsell, Steve; Harvey, Jim; Honma, Masamitsu; Kenyon, Michelle O; Kruhlak, Naomi; Muster, Wolfgang; Stavitskaya, Lidiya; Teasdale, Andrew; Vessey, Jonathan; Wichard, Joerg

    2015-10-01

    The ICH M7 guidelines for the assessment and control of DNA reactive (mutagenic) impurities in pharmaceuticals allows for the consideration of in silico predictions in place of in vitro studies. This represents a significant advance in the acceptance of (Q)SAR models and has resulted from positive interactions between modellers, regulatory agencies and industry with a shared purpose of developing effective processes to minimise risk. This paper discusses key scientific principles that should be applied when evaluating in silico predictions with a focus on accuracy and scientific rigour that will support a consistent and practical route to regulatory submission.

  8. Photonic generation of background-free millimeter-wave ultra-wideband pulses based on a single dual-drive Mach-Zehnder modulator.

    PubMed

    Li, Wei; Wang, Wen Ting; Sun, Wen Hui; Wang, Li Xian; Zhu, Ning Hua

    2014-03-01

    We propose a novel photonic approach for generating a background-free millimeter-wave (MMW) ultra-wideband (UWB) signal based on a conventional dual-drive Mach-Zehnder modulator (DMZM). One arm of the DMZM is driven by a local oscillator (LO) signal. The LO power is optimized to realize optical carrier suppressed modulation. The other arm is fed by a rectangular signal. The MMW UWB pulses are generated by truncating the continuous wave LO signal into a pulsed one in a photodetector (PD). The generated MMW UWB signal is background-free by eliminating the baseband frequency components because the optical power launched to the PD keeps constant all the time. The proposed method is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at a frequency of 26 GHz meets the Federal Communications Commission spectral mask very well.

  9. Earthquake nucleation by transient deformations caused by the M = 7.9 Denali, Alaska, earthquake

    USGS Publications Warehouse

    Gomberg, J.; Bodin, P.; Larson, K.; Dragert, H.

    2004-01-01

    The permanent and dynamic (transient) stress changes inferred to trigger earthquakes are usually orders of magnitude smaller than the stresses relaxed by the earthquakes themselves, implying that triggering occurs on critically stressed faults. Triggered seismicity rate increases may therefore be most likely to occur in areas where loading rates are highest and elevated pore pressures, perhaps facilitated by high-temperature fluids, reduce frictional stresses and promote failure. Here we show that the 2002 magnitude M = 7.9 Denali, Alaska, earthquake triggered wide-spread seismicity rate increases throughout British Columbia and into the western United States. Dynamic triggering by seismic waves should be enhanced in directions where rupture directivity focuses radiated energy, and we verify this using seismic and new high-sample GPS recordings of the Denali mainshock. These observations are comparable in scale only to the triggering caused by the 1992 M = 7.4 Landers, California, earthquake, and demonstrate that Landers triggering did not reflect some peculiarity of the region or the earthquake. However, the rate increases triggered by the Denali earthquake occurred in areas not obviously tectonically active, implying that even in areas of low ambient stressing rates, faults may still be critically stressed and that dynamic triggering may be ubiquitous and unpredictable.

  10. The 2008 M7.9 Wenchuan earthquake - Result of Local and Abnormal Mass Imbalances?

    NASA Astrophysics Data System (ADS)

    Klose, C. D.

    2008-12-01

    The May 12, 2008 M7.9 Wenchuan earthquake occurred along the Longmen Shan margin of the eastern Tibetan plateau in the Sichuan province of the People's Republic of China. A complex and NNW dipping reverse fault system including the Beichuan fault ruptured 250-300 km parallel to the Longmen Shan thrust belt. This region has been tectonically loaded for >10kyr. It has low deformation rates of less than 1.0±1.0 mm yr-1 resulting in no major seismic activity during the Quaternary period. Several geophysical observations suggest that this M7.9 earthquake was triggered by local and abnormal mass imbalances on the surface of the Earth's crust. These observations include (1) elastostatic response of the crust to the mass changes (2) slip distribution of the main rupture, and (3) aftershock distribution. Initially, approximately 2 years prior the nucleation of the mainshock, at least 320 million tonnes of water accumulated within the upper Min river valley. It enters the Chengdu plain of the Sichuan basin, a stable continental region (SCR). The water volume amplified the strain energy on the Earth's crust. Shear stresses increased by >1kPa on the Beichuan fault at the nucleation point in about 20km depth. Normal stresses decreased by <-4kPa and weakened the fault strength. Pore pressure increases might have additionally destabilized the fault locally due to pore pressure diffusion. This effect, however, might be minor in 20km depth, because of low lateral fracture connectivity and permeability between the area of water accumulation and the Beichuan fault. Overall, the stress alterations within a 120±70km2 large area resulted in the Beichuan fault coming closer to failure. Such an area ruptured would account for a M7.2±0.1 earthquake assuming only 10 MPa stress drop. Secondly, a reverse fault focal mechanism dominated, in particular, during the first 50 seconds of the main M7.9 rupture. The Beichuan fault slipped up to 7m upward peaking at shallow depth (<7km) (Nishimura

  11. Modulation of Exciton Generation in Organic Active Planar pn Heterojunction: Toward Low Driving Voltage and High-Efficiency OLEDs Employing Conventional and Thermally Activated Delayed Fluorescent Emitters.

    PubMed

    Chen, Dongcheng; Liu, Kunkun; Gan, Lin; Liu, Ming; Gao, Kuo; Xie, Gaozhan; Ma, Yuguang; Cao, Yong; Su, Shi-Jian

    2016-08-01

    Organic light-emitting diodes (OLEDs) combining low driving voltage and high efficiency are designed by employing conventional and thermally activated delayed fluorescence emitters through modulation of excitons generated at the planar p-n heterojunction region. To date, this approach enables the highest power efficiency for yellow-green emitting fluorescent OLEDs with a simplified structure.

  12. Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration

    SciTech Connect

    Hafz, N.; Hur, M. S.; Kim, G. H.; Kim, C.; Ko, I. S.; Suk, H.

    2006-01-15

    A relativistic electron bunch with a large charge (>2 nC) was produced from a self-modulated laser wakefield acceleration configuration. For this experiment, an intense laser beam with a peak power of 2 TW and a duration of 700 fs was focused in a supersonic He gas jet, and relativistic high-energy electrons were observed from the strong laser-plasma interaction. By passing the electron bunch through a small pinholelike collimator, we could generate a quasimonoenergetic high-energy electron beam, in which electrons within a cone angle of 0.25 mrad (f/70) were selected. The beam clearly showed a narrow-energy-spread behavior with a central energy of 4.3 MeV and a charge of 200 pC. The acceleration gradient was estimated to be about 30 GeV/m. Particle-in-cell simulations were performed for comparison study and the result shows that both the experimental and simulation results are in good agreement and the electron trapping is initiated by the slow beat wave of the Raman backward wave and the incident laser pulse.

  13. Dynamic combinatorial/covalent chemistry: a tool to read, generate and modulate the bioactivity of compounds and compound mixtures.

    PubMed

    Herrmann, Andreas

    2014-03-21

    Reversible covalent bond formation under thermodynamic control adds reactivity to self-assembled supramolecular systems, and is therefore an ideal tool to assess complexity of chemical and biological systems. Dynamic combinatorial/covalent chemistry (DCC) has been used to read structural information by selectively assembling receptors with the optimum molecular fit around a given template from a mixture of reversibly reacting building blocks. This technique allows access to efficient sensing devices and the generation of new biomolecules, such as small molecule receptor binders for drug discovery, but also larger biomimetic polymers and macromolecules with particular three-dimensional structural architectures. Adding a kinetic factor to a thermodynamically controlled equilibrium results in dynamic resolution and in self-sorting and self-replicating systems, all of which are of major importance in biological systems. Furthermore, the temporary modification of bioactive compounds by reversible combinatorial/covalent derivatisation allows control of their release and facilitates their transport across amphiphilic self-assembled systems such as artificial membranes or cell walls. The goal of this review is to give a conceptual overview of how the impact of DCC on supramolecular assemblies at different levels can allow us to understand, predict and modulate the complexity of biological systems.

  14. Performance improvement of phase-generated carrier method by eliminating laser-intensity modulation for optical seismometer

    NASA Astrophysics Data System (ADS)

    Shi, Qingping; Tian, Qian; Wang, Liwei; Tian, Changdong; Zhang, Huayong; Zhang, Min; Liao, Yanbiao; Wang, Honghua; Zeng, Xiang; Huang, Longjun

    2010-02-01

    An improved demodulation method for the phase-generated carrier (PGC) system by eliminating laser-intensity modulation (LIM) is proposed. The influence of LIM is analyzed theoretically and experimentally. Two parameters are used to describe the effect of LIM: the LIM coefficient (LIMC) and the LIM phase delay (LIMPD). Good stability of the LIMC and LIMPD is confirmed by experimentation with an actual system. The demodulation signal using the traditional method has a much greater higher harmonic component than the improved method due to LIM. The increase of the signal-to-total-harmonic ratio (SHR) using the improved method is >23 dB, and there is a corresponding improvement of 19 dB to the signal to noise and distortion (SINAD) and signal-to-noise ratio (SNR). A new prototype system using the improved PGC method for marine seismic sensing capable of demodulating multiple channels in parallel, simultaneously, is demonstrated. The SHR is stable at 56 dB when the LIMC is <0.5. Similar results are obtained for the SINAD and SNR. The demodulated signal's upper limit is ~100 rad at 100 Hz and 12 rad at 1 kHz, giving a dynamic range reaching 130 dB at 100 Hz. The system's SINAD is stable within 1 dB, whereas the SHR is stable within 2 dB in field application.

  15. Efficient preparation and properties of mRNAs containing a fluorescent cap analog: Anthraniloyl-m7GpppG

    PubMed Central

    Gunawardana, Dilantha; Domashevskiy, Artem V; Gayler, Ken R; Goss, Dixie J

    2015-01-01

    A method has been developed for synthesising fluorescently labeled capped mRNA. The method incorporates a single fluorescent molecule as part of the 5′-mRNA or oligonucleotide cap site. The fluorescent molecule, Ant-m7GTP is specifically incorporated into the cap site to yield Ant-m7GpppG-capped mRNA or oligonucleotide. Efficient capping was observed with 60–100% of the RNA transcripts capped with the fluorescent molecule. The Ant-m7G derivative, which has been previously shown to interact with the eukaryotic cap binding protein eIF4E, is shown in this paper to be a substrate for the Vaccinia capping enzyme and the DCP2 decapping enzyme from Arabidopsis. Further, the Ant-m7GTP-capped RNA is readily translated. This Ant-m7GTP-capped RNA provides an important tool for monitoring capping reactions, translation, and biophysical studies. PMID:26779415

  16. Camera trap records of animal activity prior to a M=7 earthquake in Northern Peru

    NASA Astrophysics Data System (ADS)

    Grant, R.; Raulin, J.; Freund, F.

    2013-12-01

    Earthquake (EQ) preparation is associated with geophysical changes occurring over many scales. Some pre-earthquake (pre-EQ) processes affect the ionosphere, others leave their mark on biota. We report (i) on ionospheric anomalies recorded prior to the M=7 Contamana EQ [1] in North-Eastern Peru, 134 km deep, associated with the subduction of the Nazca plate underneath the Northern Andes, (ii) on changes in animal activity recorded in the Yanachaga National Park, about 320 km from the EQ epicentre, over a 30 day period leading up to the M=7 seismic event. Night-time Very Low Frequency (VLF) phase data were analyzed for the period 01 June to 31 Oct. 2011 using propagation paths passing close to the Yanachaga Park from the NAA emitter (USA) to receivers PIU in Piura and PLO in Lima (Peru). Ionospheric phase perturbations were observed starting 2 weeks before the EQ with periodicities from few tens of secs to few minutes. Animal activity data were obtained by evaluating the images of a cluster of 10 motion-triggered cameras of the Tropical Ecology Assessment and Monitoring Network www.teamnetwork.org. We analyzed 1359 photographic records for the pre-EQ period and 1491 photographic records for a control period with low seismicity. Animal activity started to noticeably decline 3 weeks before the EQ. Different animal species were found to react differently. The number of rodents declined to zero about one week before the EQ and so did the number of tapirs. Armadillos, a burrowing animal, were recorded in larger numbers. Though the armadillos were presumably also flushed out of their holes, they apparently did not hide like the rodents. We discuss the results in the context of recent advances in solid state physics, which provide plausible mechanisms for pre-EQ ionospheric anomalies and for changes in animal behavior. [1] Tavera, H. (2012), Report on the 24 Aug. 2011 M 7.0 Contamana, Peru, Intermediate Depth Earthquake Seismological Research Letters, 83, 1007-1013, doi: 10.1785/0220120005

  17. Surface Rupture and Slip Distribution Resulting from the 2013 M7.7 Balochistan, Pakistan Earthquake

    NASA Astrophysics Data System (ADS)

    Reitman, N. G.; Gold, R. D.; Briggs, R. W.; Barnhart, W. D.; Hayes, G. P.

    2014-12-01

    The 24 September 2013 M7.7 earthquake in Balochistan, Pakistan, produced a ~200 km long left-lateral strike-slip surface rupture along a portion of the Hoshab fault, a moderately dipping (45-75º) structure in the Makran accretionary prism. The rupture is remarkably continuous and crosses only two (0.7 and 1.5 km wide) step-overs along its arcuate path through southern Pakistan. Displacements are dominantly strike-slip, with a minor component of reverse motion. We remotely mapped the surface rupture at 1:5,000 scale and measured displacements using high resolution (0.5 m) pre- and post-event satellite imagery. We mapped 295 laterally faulted stream channels, terrace margins, and roads to quantify near-field displacement proximal (±10 m) to the rupture trace. The maximum near-field left-lateral offset is 15±2 m (average of ~7 m). Additionally, we used pre-event imagery to digitize 254 unique landforms in the "medium-field" (~100-200 m from the rupture) and then measured their displacements compared to the post-event imagery. At this scale, maximum left-lateral offset approaches 17 m (average of ~8.5 m). The width (extent of observed surface faulting) of the rupture zone varies from ~1 m to 3.7 km. Near- and medium-field offsets show similar slip distributions that are inversely correlated with the width of the fault zone at the surface (larger offsets correspond to narrow fault zones). The medium-field offset is usually greater than the near-field offset. The along-strike surface slip distribution is highly variable, similar to the slip distributions documented for the 2002 Denali M7.9 earthquake and 2001 Kunlun M7.8 earthquake, although the Pakistan offsets are larger in magnitude. The 2013 Pakistan earthquake ranks among the largest documented continental strike-slip displacements, possibly second only to the 18+ m surface displacements attributed to the 1855 Wairarapa M~8.1 earthquake.

  18. Phase-coded microwave signal generation based on a single electro-optical modulator and its application in accurate distance measurement.

    PubMed

    Zhang, Fangzheng; Ge, Xiaozhong; Gao, Bindong; Pan, Shilong

    2015-08-24

    A novel scheme for photonic generation of a phase-coded microwave signal is proposed and its application in one-dimension distance measurement is demonstrated. The proposed signal generator has a simple and compact structure based on a single dual-polarization modulator. Besides, the generated phase-coded signal is stable and free from the DC and low-frequency backgrounds. An experiment is carried out. A 2 Gb/s phase-coded signal at 20 GHz is successfully generated, and the recovered phase information agrees well with the input 13-bit Barker code. To further investigate the performance of the proposed signal generator, its application in one-dimension distance measurement is demonstrated. The measurement accuracy is less than 1.7 centimeters within a measurement range of ~2 meters. The experimental results can verify the feasibility of the proposed phase-coded microwave signal generator and also provide strong evidence to support its practical applications.

  19. Different pulse pattern generation by frequency detuning in pulse modulated actively mode-locked ytterbium doped fiber laser

    NASA Astrophysics Data System (ADS)

    Chen, He; Chen, Sheng-Ping; Si, Lei; Zhang, Bin; Jiang, Zong-Fu

    2015-10-01

    We report the results of our recent experimental investigation of the modulation frequency detuning effect on the output pulse dynamics in a pulse modulated actively mode-locked ytterbium doped fiber laser. The experimental study shows the existence of five different mode-locking states that mainly depend on the modulation frequency detuning, which are: (a) amplitude-even harmonic/fundamental mode-locking, (b) Q-switched harmonic/fundamental mode-locking, (c) sinusoidal wave modulation mode, (d) pulses bundle state, and (e) noise-like state. A detailed experimental characterization of the output pulses dynamics in each operating mode is presented.

  20. Static stress change from the 8 October, 2005 M = 7.6 Kashmir earthquake

    USGS Publications Warehouse

    Parsons, T.; Yeats, R.S.; Yagi, Y.; Hussain, A.

    2006-01-01

    We calculated static stress changes from the devastating M = 7.6 earthquake that shook Kashmir on 8 October, 2005. We mapped Coulomb stress change on target fault planes oriented by assuming a regional compressional stress regime with greatest principal stress directed orthogonally to the mainshock strike. We tested calculation sensitivity by varying assumed stress orientations, target-fault friction, and depth. Our results showed no impact on the active Salt Range thrust southwest of the rupture. Active faults north of the Main Boundary thrust near Peshawar fall in a calculated stress-decreased zone, as does the Raikot fault zone to the northeast. We calculated increased stress near the rupture where most aftershocks occurred. The greatest increase to seismic hazard is in the Indus-Kohistan seismic zone near the Indus River northwest of the rupture termination, and southeast of the rupture termination near the Kashmir basin.

  1. Examining the ages of M7-L8 dwarfs with the BOSS Ultracool Dwarf sample

    NASA Astrophysics Data System (ADS)

    Schmidt, Sarah J.; Hawley, Suzanne L.; West, Andrew A.; Bochanski, John J.

    2016-01-01

    We present the latest results from the BOSS Ultracool Dwarfs (BUD) sample of 12998 M7-L8 dwarfs, identified from a combination of photometry and spectroscopy from the Sloan Digital Sky Survey (SDSS). Using a cross-match of the BUD sample to the Two Micron All-Sky Survey (2MASS) and the Wide-field Infrared Survey Explorer (WISE) catalogs, we measure both colors and proper motions for the majority of the sample. The proper motions, combined with radial velocities from SDSS spectra and updated distance estimates based on i-Ks colors, yield three-dimensional velocities for 9121 ultracool dwarfs. We usethese velocities as statistical proxies for age to identify and test other potential age indicators, including Hα emission, atomic line strengths, molecular band depths, and broad-band colors.

  2. Building M7-0505 Treatment Tank (SWMU 039) Annual Performance Monitoring Report

    NASA Technical Reports Server (NTRS)

    2015-01-01

    This Annual Performance Monitoring Report presents a summary of Interim Measure (IM) activities and an evaluation of data collected during the third year (June 2014 to September 2015) of operation, maintenance, and monitoring (OM&M) conducted at the Building M7-505 (M505) Treatment Tank area, Kennedy Space Center (KSC), Florida ("the Site"). Under KSC's Resource Conservation and Recovery Act Corrective Action Program, the M505 Treatment Tank area was designated Solid Waste Management Unit 039. Arcadis U.S., Inc. (Arcadis) began IM activities on January 10, 2012, after completion of construction of an in situ air sparge (IAS) system to remediate volatile organic compounds (VOCs) in groundwater at concentrations exceeding applicable Florida Department of Environmental Protection (FDEP) Chapter 62-777, Florida Administrative Code, Natural Attenuation Default Concentrations (NADCs). This report presents a summary of the third year of OM&M activities conducted between June 2014 and September 2015.

  3. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession. PMID:16623137

  4. Large rock avalanches triggered by the M 7.9 Denali Fault, Alaska, earthquake of 3 November 2002

    USGS Publications Warehouse

    Jibson, R.W.; Harp, E.L.; Schulz, W.; Keefer, D.K.

    2006-01-01

    The moment magnitude (M) 7.9 Denali Fault, Alaska, earthquake of 3 November 2002 triggered thousands of landslides, primarily rock falls and rock slides, that ranged in volume from rock falls of a few cubic meters to rock avalanches having volumes as great as 20 ?? 106 m3. The pattern of landsliding was unusual: the number and concentration of triggered slides was much less than expected for an earthquake of this magnitude, and the landslides were concentrated in a narrow zone about 30-km wide that straddled the fault-rupture zone over its entire 300-km length. Despite the overall sparse landslide concentration, the earthquake triggered several large rock avalanches that clustered along the western third of the rupture zone where acceleration levels and ground-shaking frequencies are thought to have been the highest. Inferences about near-field strong-shaking characteristics drawn from interpretation of the landslide distribution are strikingly consistent with results of recent inversion modeling that indicate that high-frequency energy generation was greatest in the western part of the fault-rupture zone and decreased markedly to the east. ?? 2005 Elsevier B.V. All rights reserved.

  5. In vivo modulation of interacting central pattern generators in lobster stomatogastric ganglion: influence of feeding and partial pressure of oxygen.

    PubMed

    Clemens, S; Massabuau, J C; Legeay, A; Meyrand, P; Simmers, J

    1998-04-01

    The stomatogastric ganglion (STG) of the European lobster Homarus gammarus contains two rhythm-generating networks (the gastric and pyloric circuits) that in resting, unfed animals produce two distinct, yet strongly interacting, motor patterns. By using simultaneous EMG recordings from the gastric and pyloric muscles in vivo, we found that after feeding, the gastropyloric interaction disappears as the two networks express accelerated motor rhythms. The return to control levels of network activity occurs progressively over the following 1-2 d and is associated with a gradual reappearance of the gastropyloric interaction. In parallel with this change in network activity is an alteration of oxygen levels in the blood. In resting, unfed animals, arterial partial pressure of oxygen (PO2) is most often between 1 and 2 kPa and then doubles within 1 hr after feeding, before returning to control values some 24 hr later. In vivo, experimental prevention of the arterial PO2 increase after feeding leads to a slowing of pyloric rhythmicity toward control values and a reappearance of the gastropyloric interaction, without apparent effect on gastric network operation. Using in vitro preparations of the stomatogastric nervous system and by changing oxygen levels uniquely at the level of the STG within the range observed in the intact animal, we were able to mimic most of the effects observed in vivo. Our data indicate that the gastropyloric interaction appears only during a "free run" mode of foregut activity and that the coordinated operation of multiple neural networks may be modulated by local changes in oxygenation. PMID:9502835

  6. Quercetin Modulates the Effects of Chromium Exposure on Learning, Memory and Antioxidant Enzyme Activity in F1 Generation Mice.

    PubMed

    Halder, Sumita; Kar, Rajarshi; Mehta, Ashish K; Bhattacharya, Swapan K; Mediratta, Pramod K; Banerjee, Basu D

    2016-06-01

    In the present study, we investigated whether chromium (Cr) administered to the dams (F0) during lactation period could affect memory and oxidative stress in F1 generation mice in their adulthood and whether quercetin could modulate these effects. Morris water maze (MWM) was used to test for spatial memory. Passive avoidance task and elevated plus maze were used to test for acquisition and retention memory. Oxidative stress was evaluated by measuring glutathione-S-transferase (GST), catalase activity and malonaldehyde (MDA) levels in the brain tissue. The results of MWM showed that the animals in the Cr-treated group compared to control have better spatial memory that was further enhanced when Cr was administered along with quercetin (50 mg/kg). The elevated plus maze test also showed the Cr-treated group to improve acquisition as well as retention memory compared to control. Co-treatment with quercetin (all doses) also exhibited enhanced acquisition and retention memory compared to control. The passive avoidance task demonstrated no significant improvement in memory in the Cr-treated mice but co-treatment with quercetin (100 mg/kg) showed improved acquisition memory compared to control which was significantly better than the animals treated with chromium alone. GST activity was significantly increased in the Cr-treated animals, and this was further increased in groups treated with Cr and quercetin (all doses). Chromium when administered alone and in combination with quercetin (all doses) significantly reduced MDA levels. However, Cr treatment did not show significant change in catalase activity. Nevertheless, co-treatment with quercetin (25 and 50 mg/kg) resulted in significant decrease in catalase activity. Thus, our study demonstrates that Cr exposure during lactation could be beneficial for pups with respect to augmentation of cognitive function and reduction of oxidative stress. Quercetin could probably enhance this effect to some extent.

  7. Dopaminergic Presynaptic Modulation of Nigral Afferents: Its Role in the Generation of Recurrent Bursting in Substantia Nigra Pars Reticulata Neurons

    PubMed Central

    de Jesús Aceves, José; Rueda-Orozco, Pavel E.; Hernández, Ricardo; Plata, Víctor; Ibañez-Sandoval, Osvaldo; Galarraga, Elvira; Bargas, José

    2011-01-01

    Previous work has shown the functions associated with activation of dopamine presynaptic receptors in some substantia nigra pars reticulata (SNr) afferents: (i) striatonigral terminals (direct pathway) posses presynaptic dopamine D1-class receptors whose action is to enhance inhibitory postsynaptic currents (IPSCs) and GABA transmission. (ii) Subthalamonigral terminals posses D1- and D2-class receptors where D1-class receptor activation enhances and D2-class receptor activation decreases excitatory postsynaptic currents. Here we report that pallidonigral afferents posses D2-class receptors (D3 and D4 types) that decrease inhibitory synaptic transmission via presynaptic modulation. No action of D1-class agonists was found on pallidonigral synapses. In contrast, administration of D1-receptor antagonists greatly decreased striatonigral IPSCs in the same preparation, suggesting that tonic dopamine levels help in maintaining the function of the striatonigral (direct) pathway. When both D3 and D4 type receptors were blocked, pallidonigral IPSCs increased in amplitude while striatonigral connections had no significant change, suggesting that tonic dopamine levels are repressing a powerful inhibition conveyed by pallidonigral synapses (a branch of the indirect pathway). We then blocked both D1- and D2-class receptors to acutely decrease direct pathway (striatonigral) and enhance indirect pathways (subthalamonigral and pallidonigral) synaptic force. The result was that most SNr projection neurons entered a recurrent bursting firing mode similar to that observed during Parkinsonism in both patients and animal models. These results raise the question as to whether the lack of dopamine in basal ganglia output nuclei is enough to generate some pathological signs of Parkinsonism. PMID:21347219

  8. Quercetin Modulates the Effects of Chromium Exposure on Learning, Memory and Antioxidant Enzyme Activity in F1 Generation Mice.

    PubMed

    Halder, Sumita; Kar, Rajarshi; Mehta, Ashish K; Bhattacharya, Swapan K; Mediratta, Pramod K; Banerjee, Basu D

    2016-06-01

    In the present study, we investigated whether chromium (Cr) administered to the dams (F0) during lactation period could affect memory and oxidative stress in F1 generation mice in their adulthood and whether quercetin could modulate these effects. Morris water maze (MWM) was used to test for spatial memory. Passive avoidance task and elevated plus maze were used to test for acquisition and retention memory. Oxidative stress was evaluated by measuring glutathione-S-transferase (GST), catalase activity and malonaldehyde (MDA) levels in the brain tissue. The results of MWM showed that the animals in the Cr-treated group compared to control have better spatial memory that was further enhanced when Cr was administered along with quercetin (50 mg/kg). The elevated plus maze test also showed the Cr-treated group to improve acquisition as well as retention memory compared to control. Co-treatment with quercetin (all doses) also exhibited enhanced acquisition and retention memory compared to control. The passive avoidance task demonstrated no significant improvement in memory in the Cr-treated mice but co-treatment with quercetin (100 mg/kg) showed improved acquisition memory compared to control which was significantly better than the animals treated with chromium alone. GST activity was significantly increased in the Cr-treated animals, and this was further increased in groups treated with Cr and quercetin (all doses). Chromium when administered alone and in combination with quercetin (all doses) significantly reduced MDA levels. However, Cr treatment did not show significant change in catalase activity. Nevertheless, co-treatment with quercetin (25 and 50 mg/kg) resulted in significant decrease in catalase activity. Thus, our study demonstrates that Cr exposure during lactation could be beneficial for pups with respect to augmentation of cognitive function and reduction of oxidative stress. Quercetin could probably enhance this effect to some extent. PMID:26521059

  9. Simultaneous Generations of Independent Millimeter Wave and 10 Gbit/s Wired Signal by Single Electrode Modulator in TDM-PON Network

    NASA Astrophysics Data System (ADS)

    Niazi, Shahab Ahmad; Zhang, Xiaoguang; Xi, Lixia; Idress, Muhammad

    2013-03-01

    We propose and present a cost effective and simple technique of simultaneous generation and propagation of millimeter wave with recently standardized 10 giga bit passive optical network (GPON) by mixing of 2.5 Gbit/s, 30 GHz radio wave with 10 Gbit/s based band signal and then modulated by single Mach Zehnder modulator (MZM). In this scheme, we have applied 1490 nm for downstream, 1310 nm for upstream transmission and ON OFF keying (OOK) modulation format to make it fully align with existing standards and infrastructure. Simulation results show error free transmission performance with negligible power penalty over 25 km bidirectional fiber. We also highlight the principles and discuss the main technical challenges for commercial realization of 60 GHz spectrum.

  10. Earthquake Forecasts for Gorkha Immediately Following the 25th April, M=7.8 Mainshock

    NASA Astrophysics Data System (ADS)

    Segkou, M.; Parsons, T.

    2015-12-01

    The M-7.8 Gorkha (Nepal) earthquake on the 25th April, 2015 has shaken the central Himalayan front and immediately raised concerns for the severity of future triggered earthquakes. Here, we implement standard and innovative forecast models to predict the spatio-temporal distribution of triggered events. Key challenges addressed are: 1) the limited information on early aftershocks, 2) the low-productivity aftershock sequence in the near-source area, 3) the off-fault (>250 km) triggered events exemplified by the M=5.4 Xegar event, 3 hrs after the mainshock. We apply short-term empirical/statistical ETAS and physical forecast models, the latter based on the combination of rate/state friction law and Coulomb stresses. Within the physics-based model implementation we seek to evaluate the uncertainty related with the rupture style of triggered events by considering: 1) the geometry of active structures, 2) optimally oriented for failure faults and 3) all-potential faults described by the total stress field. The latter is represented by the full stress tensor before and after the mainshock and our analysis suggests that the preseismic stress magnitudes are still sufficient to cause earthquakes even after modification by the mainshock. The above remark reveals that there are no "stress shadows" affecting the spatial distribution of near-field aftershocks. It is also noted that the method allows for an a-priori determination of the rupture plan of the M=7.3 event, within the limit of uncertainty (20˚). The results show that: (1) ETAS models underestimate the number of observed events, since they heavily base their good performance in small magnitude earthquakes, not available in the first few weeks after the mainshock, (2) far field triggered events are captured only by physics-based forecasts, and (3) the total stress method improves the predictability of larger magnitude events. We conclude that frontier regions benefit from the implementation of physics-based models

  11. Modulating the Electronic Properties of Monolayer Graphene Using a Periodic Quasi-One-Dimensional Potential Generated by Hex-Reconstructed Au(001).

    PubMed

    Zhou, Xiebo; Qi, Yue; Shi, Jianping; Niu, Jingjing; Liu, Mengxi; Zhang, Guanhua; Li, Qiucheng; Zhang, Zhepeng; Hong, Min; Ji, Qingqing; Zhang, Yu; Liu, Zhongfan; Wu, Xiaosong; Zhang, Yanfeng

    2016-08-23

    The structural and electronic properties of monolayer graphene synthesized on a periodically reconstructed substrate can be widely modulated by the generation of superstructure patterns, thereby producing interesting physical properties, such as magnetism and superconductivity. Herein, using a facile chemical vapor deposition method, we successfully synthesized high-quality monolayer graphene with a uniform thickness on Au foils. The hex-reconstruction of Au(001), which is characterized by striped patterns with a periodicity of 1.44 nm, promoted the formation of a quasi-one-dimensional (1D) graphene superlattice, which served as a periodic quasi-1D modulator for the graphene overlayer, as evidenced by scanning tunneling microscopy/spectroscopy. Intriguingly, two new Dirac points were generated for the quasi-1D graphene superlattice located at -1.73 ± 0.02 and 1.12 ± 0.12 eV. Briefly, this work demonstrates that the periodic modulation effect of reconstructed metal substrates can dramatically alter the electronic properties of graphene and provides insight into the modulation of these properties using 1D potentials. PMID:27478993

  12. A compact, all-optical, THz wave generator based on self-modulation in a slab photonic crystal waveguide with a single sub-nanometer graphene layer.

    PubMed

    Asadi, R; Ouyang, Z; Mohammd, M M

    2015-07-14

    We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits.

  13. Compact fiber-pigtailed InGaAs photoconductive antenna module for terahertz-wave generation and detection.

    PubMed

    Han, Sang-Pil; Kim, Namje; Ko, Hyunsung; Ryu, Han-Cheol; Park, Jeong-Woo; Yoon, Young-Jong; Shin, Jun-Hwan; Lee, Dong Hun; Park, Sang-Ho; Moon, Seok-Hwan; Choi, Sung-Wook; Chun, Hyang Sook; Park, Kyung Hyun

    2012-07-30

    We propose a compact fiber-pigtailed InGaAs photoconductive antenna (FPP) module having an effective heat-dissipation solution as well as a module volume of less than 0.7 cc. The heat-dissipation of the FPP modules when using a heat-conductive printed circuit board (PCB) and an aluminium nitride (AlN) submount, without any cooling systems, improve by 40% and 85%, respectively, when compared with a photoconductive antenna chip on a conventional PCB. The AlN submount is superior to those previously reported as a heat-dissipation solution. Terahertz time-domain spectroscopy (THz-TDS) using the FPP module perfectly detects the absorption lines of water vapor in free space and an α-lactose sample. PMID:23038394

  14. Evidence of shallow fault zone strengthening after the 1992 M7.5 landers, california, earthquake

    PubMed

    Li; Vidale; Aki; Xu; Burdette

    1998-01-01

    Repeated seismic surveys of the Landers, California, fault zone that ruptured in the magnitude (M) 7.5 earthquake of 1992 reveal an increase in seismic velocity with time. P, S, and fault zone trapped waves were excited by near-surface explosions in two locations in 1994 and 1996, and were recorded on two linear, three-component seismic arrays deployed across the Johnson Valley fault trace. The travel times of P and S waves for identical shot-receiver pairs decreased by 0.5 to 1.5 percent from 1994 to 1996, with the larger changes at stations located within the fault zone. These observations indicate that the shallow Johnson Valley fault is strengthening after the main shock, most likely because of closure of cracks that were opened by the 1992 earthquake. The increase in velocity is consistent with the prevalence of dry over wet cracks and with a reduction in the apparent crack density near the fault zone by approximately 1.0 percent from 1994 to 1996.

  15. Seismotectonic environment of occurring the February 3, 1996 Lijiang M=7.0 earthquake, Yunnan province

    NASA Astrophysics Data System (ADS)

    Han, Zhu-Jun; Guo, Shun-Min; Xiang, Hong-Fa; Zhang, Jia-Sheng; Ran, Yong-Kang

    2004-07-01

    Lijiang-Daju fault, the seismogenic fault of the 1996 Lijiang M=7.0 earthquake, can be divided into Lijiang-Yuhu segment in the south and Yuhu-Daju segment in the north. The two segments show clear difference in geological tectonics, but have the similar dynamic features. Both normal dip-slip and sinistral strike-slip coexist on the fault plane. This kind of movement started at the beginning of the Quaternary (2.4 2.5 Ma B.P.). As to the tectonic types, the detachment fault with low angle was developed in the Early Pleistocene and the normal fault with high angle only after the Mid-Pleistocene (0.8 Ma B.P.). Based on the horizontal displacements of gullies and the vertical variance of planation surfaces cross the Lijiang-Daju fault at east piedmont of Yulong-Haba range, the average horizontal and vertical slip rates are calculated. They are 0.84 mm/a and 0.70 mm/a since the Quaternary and 1.56 mm/a and 1.69 mm/a since the Mid-Pleistocene. The movements of the nearly N-S-trending Lijiang-Daju fault are controlled not only by the regional stress field, but also by the variant movement between the Yulong-Haba range and Lijiang basin. The two kinds of dynamic processes form the characteristics of seismotectonic environment of occurring the 1996 Lijiang earthquake.

  16. Evidence of shallow fault zone strengthening after the 1992 M7.5 Landers, California, earthquake

    USGS Publications Warehouse

    Li, Y.-G.; Vidale, J.E.; Aki, K.; Xu, Fei; Burdette, T.

    1998-01-01

    Repeated seismic surveys of the Landers, California, fault zone that ruptured in the magnitude (M) 7.5 earthquake of 1992 reveal an increase in seismic velocity with time. P, S, and fault zone trapped waves were excited by near-surface explosions in two locations in 1994 and 1996, and were recorded on two linear, three-component seismic arrays deployed across the Johnson Valley fault trace. The travel times of P and S waves for identical shot-receiver pairs decreased by 0.5 to 1.5 percent from 1994 to 1996, with the larger changes at stations located within the fault zone. These observations indicate that the shallow Johnson Valley fault is strengthening after the main shock, most likely because of closure of cracks that were opened by the 1992 earthquake. The increase in velocity is consistent with the prevalence of dry over wet cracks and with a reduction in the apparent crack density near the fault zone by approximately 1.0 percent from 1994 to 1996.

  17. Generation of Three-phase Zero-phase-Sequence Output Components by the Switching Modulation Technique and its Application to Hot-line Insulation Diagnosis System

    NASA Astrophysics Data System (ADS)

    Akatani, Masami; Yokoi, Yoshihide; Isaka, Katsuo

    This paper deals with a power supply using switching modulation technique, and its application to the hot-line insulation diagnosis. One of the distinct features of the switching modulation techinque employed in this study is that the zero-phase-sequence voltage with arbitary frequency is generated easily in the three-phase power system. Basic composition is just to add a switching modulation device to the commercial power supply or charged indoor main line. Therefore, it is not necessary to feed a signal current from the signal power supply to the grounding conductor via a pouring transformer as required by current hot-line insulation diagnosis system. When a power supply using switching modulation technique is used to hot-line insulation diagnosis, it is not necessary to modify or change existing commercial power facility. Therefore, there is a possibility that this may advantageously be used as a power supply for mobile type diagnosis. This paper deals with basic theory of switching modulation technique, and the phase rotation characteristics which play a basic role in three-phase power supply, and summarizes basic composition and performances of a trial manufactured experimental device. Furthermore, results of discussion are introduced concerning the conditions and method of its apllication to indoor wiring of fatories and buildings.

  18. Simulations of Orographic Mixed-Phase Clouds at Mountain Range Site using COSMO-ART-M7

    NASA Astrophysics Data System (ADS)

    Henneberg, Olga; Henneberger, Jan; Lohmann, Ulrike

    2015-04-01

    -moment microphysics scheme, show the occurrence of MPCs in accordance with the measurements with mass concentration of liquid and ice phase on the same order of magnitude as observed but the high ice number concentration observed at JFJ can not be captured by the simulations with the current setup. As the processes leading to such high ice concentration are not well understood yet it is not clear if they are considered by the model. The correlation between updraft velocities and occurrence of liquid water content found in the measurement results can also be seen in the first simulations with COSMO for some chosen days in February and April 2013 based on the measurements. Nevertheless the simulations also confirm that occurrence of MPC can not exclusively be explained by updraft velocities. Further simulations with modified aerosol concentrations and coupled to the ART-M7 module will explore influences of aerosols on clouds at JFJ.

  19. Triangular pulse generation using a dual-parallel Mach-Zehnder modulator driven by a single-frequency radio frequency signal.

    PubMed

    Zhang, Fangzheng; Ge, Xiaozhong; Pan, Shilong

    2013-11-01

    A simple scheme for the generation of full-duty-cycle triangular pulses is proposed and experimentally demonstrated using a dual-parallel Mach-Zehnder modulator driven by a single-frequency RF signal. By properly setting the bias voltages and the RF power, even-order harmonics in the optical intensity are suppressed, and the amplitude of the first-order harmonic is 9 times of that of the third-order harmonic. A periodical triangular pulse train is obtained in the time domain. 2.5, 5, and 10 GHz triangular pulse trains are experimentally generated, which verifies the feasibility of the proposed scheme.

  20. Numerical study of the generation and propagation of ultralow-frequency waves by artificial ionospheric F region modulation at different latitudes

    NASA Astrophysics Data System (ADS)

    Xu, Xiang; Zhou, Chen; Shi, Run; Ni, Binbin; Zhao, Zhengyu; Zhang, Yuannong

    2016-09-01

    Powerful high-frequency (HF) radio waves can be used to efficiently modify the upper-ionospheric plasmas of the F region. The pressure gradient induced by modulated electron heating at ultralow-frequency (ULF) drives a local oscillating diamagnetic ring current source perpendicular to the ambient magnetic field, which can act as an antenna radiating ULF waves. In this paper, utilizing the HF heating model and the model of ULF wave generation and propagation, we investigate the effects of both the background ionospheric profiles at different latitudes in the daytime and nighttime ionosphere and the modulation frequency on the process of the HF modulated heating and the subsequent generation and propagation of artificial ULF waves. Firstly, based on a relation among the radiation efficiency of the ring current source, the size of the spatial distribution of the modulated electron temperature and the wavelength of ULF waves, we discuss the possibility of the effects of the background ionospheric parameters and the modulation frequency. Then the numerical simulations with both models are performed to demonstrate the prediction. Six different background parameters are used in the simulation, and they are from the International Reference Ionosphere (IRI-2012) model and the neutral atmosphere model (NRLMSISE-00), including the High Frequency Active Auroral Research Program (HAARP; 62.39° N, 145.15° W), Wuhan (30.52° N, 114.32° E) and Jicamarca (11.95° S, 76.87° W) at 02:00 and 14:00 LT. A modulation frequency sweep is also used in the simulation. Finally, by analyzing the numerical results, we come to the following conclusions: in the nighttime ionosphere, the size of the spatial distribution of the modulated electron temperature and the ground magnitude of the magnetic field of ULF wave are larger, while the propagation loss due to Joule heating is smaller compared to the daytime ionosphere; the amplitude of the electron temperature oscillation decreases with

  1. Next Generation Fast RF Interlock Module and ATCA Adapter for ILC High Availability RF Test Station Demonstration

    SciTech Connect

    Larsen, R

    2009-10-17

    High availability interlocks and controls are required for the ILC (International Linear Collider) L-Band high power RF stations. A new F3 (Fast Fault Finder) VME module has been developed to process both fast and slow interlocks using FPGA logic to detect the interlock trip excursions. This combination eliminates the need for separate PLC (Programmable Logic Controller) control of slow interlocks. Modules are chained together to accommodate as many inputs as needed. In the next phase of development the F3's will be ported to the new industry standard ATCA (Advanced Telecom Computing Architecture) crate (shelf) via a specially designed VME adapter module with IPMI (Intelligent Platform Management Interface). The goal is to demonstrate auto-failover and hot-swap for future partially redundant systems.

  2. Power-Generation Performance of a π-Structured Thermoelectric Module Containing Mg2Si and MnSi1.73

    NASA Astrophysics Data System (ADS)

    Nakamura, Tomoyuki; Hatakeyama, Kazuya; Minowa, Masahiro; Mito, Youhiko; Arai, Koya; Iida, Tsutomu; Nishio, Keishi

    2015-10-01

    In recent years, environmental problems, for example global warming and depletion of energy resources, have become serious. Thermoelectric power generation has attracted attention as a means of reducing the effects of such problems. Thermoelectric conversion technology can convert thermal energy directly into electrical energy. Therefore, exhaust heat can be converted into electrical energy. Moreover, it is a clean method of power generation that does not discharge CO2 gas when the electricity is generated. The purpose of this study was to fabricate a thermoelectric (TE) module that can be used at mid-range temperatures of 573-873 K. The component materials selected were Mg2Si as n-type semiconductor and MnSi1.73 as p-type semiconductor. These compounds are non-toxic, environmentally benign, lightweight, and relatively abundant compared with other TE compounds. Ag paste was used to join the components. To prevent diffusion of Ag at the interface of the components and the electrodes, the top and bottom of the components were coated with Ni. The TE module was composed of 12 pairs of elements and Ag seats were used for the electrodes. The dimensions of both p and n-type components were 5.0 mm × 5.0 mm × 6.3 mm. Module size was 36.5 mm × 36.0 mm × 7.0 mm, and alumina was used as substrate. The module was inserted between hot and cold plates, in air, and output power was measured. The open circuit voltage and the maximum output power were 1.6 V and 5.6 W, respectively, at Δ T = 548°C (hot side 587°C; cold side 39°C), and the output power density estimated from these results was 4.4 kW/m2.

  3. Versatility of Streptomyces sp. M7 to bioremediate soils co-contaminated with Cr(VI) and lindane.

    PubMed

    Aparicio, JuanDaniel; Solá, María Zoleica Simón; Benimeli, Claudia Susana; Amoroso, María Julia; Polti, Marta Alejandra

    2015-06-01

    The aim of this work was to study the impact of environmental factors on the bioremediation of Cr(VI) and lindane contaminated soil, by an actinobacterium, Streptomyces sp. M7, in order to optimize the process. Soil samples were contaminated with 25 µg kg(-1) of lindane and 50 mg kg(-1) of Cr(VI) and inoculated with Streptomyces sp. M7. The lowest inoculum concentration which simultaneously produced highest removal of Cr(VI) and lindane was 1 g kg(-1). The influence of physical and chemical parameters was assessed using a full factorial design. The factors and levels tested were: Temperature: 25, 30, 35°C; Humidity: 10%, 20%, 30%; Initial Cr(VI) concentration: 20, 50, 80 mg kg(-1); Initial lindane concentration: 10, 25, 40 µg kg(-1). Streptomyces sp. M7 exhibited strong versatility, showing the ability to bioremediate co-contaminated soil samples at several physicochemical conditions. Streptomyces sp. M7 inoculum size was optimized. Also, it was fitted a model to study this process, and it was possible to predict the system performance, knowing the initial conditions. Moreover, optimum temperature and humidity conditions for the bioremediation of soil with different concentrations of Cr(VI) and lindane were determined. Lettuce seedlings were a suitable biomarker to evaluate the contaminants mixture toxicity. Streptomyces sp. M7 carried out a successful bioremediation, which was demonstrated through ecotoxicity test with Lactuca sativa. PMID:25749405

  4. Versatility of Streptomyces sp. M7 to bioremediate soils co-contaminated with Cr(VI) and lindane.

    PubMed

    Aparicio, JuanDaniel; Solá, María Zoleica Simón; Benimeli, Claudia Susana; Amoroso, María Julia; Polti, Marta Alejandra

    2015-06-01

    The aim of this work was to study the impact of environmental factors on the bioremediation of Cr(VI) and lindane contaminated soil, by an actinobacterium, Streptomyces sp. M7, in order to optimize the process. Soil samples were contaminated with 25 µg kg(-1) of lindane and 50 mg kg(-1) of Cr(VI) and inoculated with Streptomyces sp. M7. The lowest inoculum concentration which simultaneously produced highest removal of Cr(VI) and lindane was 1 g kg(-1). The influence of physical and chemical parameters was assessed using a full factorial design. The factors and levels tested were: Temperature: 25, 30, 35°C; Humidity: 10%, 20%, 30%; Initial Cr(VI) concentration: 20, 50, 80 mg kg(-1); Initial lindane concentration: 10, 25, 40 µg kg(-1). Streptomyces sp. M7 exhibited strong versatility, showing the ability to bioremediate co-contaminated soil samples at several physicochemical conditions. Streptomyces sp. M7 inoculum size was optimized. Also, it was fitted a model to study this process, and it was possible to predict the system performance, knowing the initial conditions. Moreover, optimum temperature and humidity conditions for the bioremediation of soil with different concentrations of Cr(VI) and lindane were determined. Lettuce seedlings were a suitable biomarker to evaluate the contaminants mixture toxicity. Streptomyces sp. M7 carried out a successful bioremediation, which was demonstrated through ecotoxicity test with Lactuca sativa.

  5. Background-free millimeter-wave ultra-wideband signal generation based on a dual-parallel Mach-Zehnder modulator.

    PubMed

    Zhang, Fangzheng; Pan, Shilong

    2013-11-01

    A novel scheme for photonic generation of a millimeter-wave ultra-wideband (MMW-UWB) signal is proposed and experimentally demonstrated based on a dual-parallel Mach-Zehnder modulator (DPMZM). In the proposed scheme, a single-frequency radio frequency (RF) signal is applied to one sub-MZM of the DPMZM to achieve optical suppressed-carrier modulation, and an electrical control pulse train is applied to the other sub-MZM biased at the minimum transmission point, to get an on/off switchable optical carrier. By filtering out the optical carrier with one of the first-order sidebands, and properly setting the amplitude of the control pulse, an MMW-UWB pulse train without the residual local oscillation is generated after photo-detection. The generated MMW-UWB signal is background-free, because the low-frequency components in the electrical spectrum are effectively suppressed. In the experiment, an MMW-UWB pulse train centered at 25 GHz with a 10-dB bandwidth of 5.5 GHz is successfully generated. The low frequency components are suppressed by 22 dB.

  6. Experimental investigation of a spiral-wound pressure-retarded osmosis membrane module for osmotic power generation.

    PubMed

    Kim, Yu Chang; Kim, Young; Oh, Dongwook; Lee, Kong Hoon

    2013-03-19

    Pressure-retarded osmosis (PRO) uses a semipermeable membrane to produce renewable energy from salinity-gradient energy. A spiral-wound (SW) design is one module configuration of the PRO membrane. The SW PRO membrane module has two different flow paths, axial and spiral, and two different spacers, net and tricot, for draw- and feed-solution streams, respectively. This study used an experimental approach to investigate the relationship between two interacting flow streams in a prototype SW PRO membrane module, and the adverse impact of a tricot fabric spacer (as a feed spacer) on the PRO performance, including water flux and power density. The presence of the tricot spacer inside the membrane envelope caused a pressure drop due to flow resistance and reduced osmotic water permeation due to the shadow effect. The dilution of the draw solution by water permeation resulted in the reduction of the osmotic pressure difference along a pressure vessel. For a 0.6 M NaCl solution and tap water, the water flux and corresponding maximum power density were 3.7 L m(-2)h(-1) and 1.0 W/m(2) respectively at a hydraulic pressure difference of 9.8 bar. The thickness and porosity of the tricot spacer should be optimized to achieve high SW PRO module performance.

  7. Macroscopic anomalies before the September 2010 M = 7.1 earthquake in Christchurch, New Zealand

    NASA Astrophysics Data System (ADS)

    Whitehead, N. E.; Ulusoy, Ü.

    2013-01-01

    Previous published work after the Kobe and İzmit earthquakes (1995 and 1999, respectively) demonstrated some reported meteorological and animal behaviour precursors were valid. Predictions were freshly tested for the Christchurch earthquake (M = 7.1, 4 September 2010). An internet survey with nearly 400 valid replies showed relative numbers of reports in precursor categories the day before the quake, were statistically significantly different from those in the preceding three days (excess meteorological events and animal behaviour). The day before the quake, there was also altered relative precursor class occurrence within 56 km compared with further away. Both these confirmed the earlier published work. Owners were woken up by unique pet behaviour 12 times as often in the hour before the quake compared with other hours immediately before (statistically highly significant). Lost and Found pet reports were double normal the week before, and 4.5 times normal both the day before the quake, and 9 days before. (Results were again statistically significant). Unique animal behaviour before the quake was often repeated before the numerous aftershocks. These pet owners claimed an approximate 80% prediction reliability. However, a preliminary telephone survey suggested that animals showing any precursor response are a minority. Some precursors seem real, but usefulness seemed mostly restricted to 7 cases where owners were in, or near, a place of safety through disruptive pet behaviour, and one in which owners were diverted by a pet from being struck by falling fixtures. For a later 22 February 2011 M = 6.3 quake no reports of escape through warning by pets were recorded, which raises serious questions whether such prediction is practically useful, because lives claimed saved are extremely low compared with fatalities. It is shown the lost-pet statistics dates, correspond to ionospheric anomalies recorded using the GPS satellite system and geomagnetic disturbance data, and

  8. The Equatorial Annual Oscillation (EAO) as Upper Atmosphere Pacemaker for Generating the Large Solar Cycle Modulation of the QBO in the Stratosphere: Model Simulations and Observations

    NASA Astrophysics Data System (ADS)

    Mayr, H. G.; Lee, J. N.

    2014-12-01

    Very large solar cycle (SC) variations are observed in the zonal winds and temperatures of the quasi-biennial oscillation (QBO). The effect is too large to be produced by the small SC variations of the solar flux in the lower stratosphere. Dynamical downward coupling must be involved, and we present a review of the mechanism that emerged from studies with the Numerical Spectral Model (NSM). In the NSM, the QBO is generated with parameterized gravity waves and planetary waves. For a SC period of 10 years, the applied heat source varies exponentially with altitude: 0.2% (surface), 2% (50 km), 20% (100 km and above). With that solar forcing, the model reproduces qualitatively the SC modulations of the QBO zonal winds around the equator and temperature variations extending to high latitudes. The QBO is spawned in the lower mesosphere by a hemispherically symmetric equatorial annual oscillation (EAO) of the zonal wind velocities. Though small in magnitude, the SC modulation of the EAO is large. Like the symmetric QBO, the EAO extends into the lower atmosphere under the influence of, and amplified by, wave mean flow interactions. The amplitude modulations of the QBO and EAO are in phase with the imposed SC heat source. Essentially, the EAO provides the pathway and pacemaker for the SC modulation of the QBO - and wave interactions amplify the oscillations as they propagate down into the lower atmosphere. Analysis of NCEP temperature and zonal wind data (1958 to 2006) produces the hemispherically symmetric equatorial annual oscillation (EAO), and it contains spectral signatures with periods around 11 years. Moving windows of 44 years show that below 20 km the 11-year modulation of the EAO is phase locked to the SC. The spectral features from the 48-year data record reveal modulation signatures of 9.6 and 12 years, which produce EAO variations that mimic in limited altitude regimes the varying maxima and minima of the 10.7 cm solar index. In the lower stratosphere, the 40

  9. The M7 October 21, 1868 Hayward Earthquake, Northern California-140 Years Later

    NASA Astrophysics Data System (ADS)

    Brocher, T. M.; Boatwright, J.; Lienkaemper, J. J.; Schwartz, D. P.; Garcia, S.

    2007-12-01

    October 21, 2008 marks the 140th anniversary of the M7 1868 Hayward earthquake. This large earthquake, which occurred slightly before 8 AM, caused extensive damage to San Francisco Bay Area and remains the nation's 12th most lethal earthquake. Property loss was extensive and about 30 people were killed. This earthquake culminated a decade-long series of earthquakes in the Bay Area which started with an M~6 earthquake in the southern Peninsula in 1856, followed by a series of four M5.8 to M6.1 sized earthquakes along the northern Calaveras fault, and ended with a M~6.5 earthquake in the Santa Cruz Mountains in 1865. Despite this flurry of quakes, the shaking from the 1868 earthquake was the strongest that the new towns and growing cities of the Bay Area had ever experienced. The effect on the brick buildings of the time was devastating: walls collapsed in San Francisco, Oakland, and San Jose, and buildings cracked as far away as Napa, Santa Rosa, and Hollister. The area that was strongly shaken (at Modified Mercalli Intensity VII or higher) encompassed about 2,300 km2. Aftershocks continued into November 1868. Surface cracking of the ground along the southern end of the Hayward Fault was traced from Warm Springs in Fremont northward 32 km to San Leandro. As Lawson (1908) reports, "the evidence to the northward of San Leandro is not very satisfactory. The country was then unsettled, and the information consisted of reports of cow- boys riding on the range". Analysis of historical triangulation data suggest that the fault moved as far north as Berkeley, and from these data the average slip along the fault is inferred to be about 1.9 ± 0.4 meters. The paleoseismic record from the southern end of the Hayward Fault provides evidence for 10 earthquakes before 1868. The average interval between these earthquakes is 170 ± 80 years, but the last five earthquakes have had an average interval of only 140 ± 50 years. The 1868 Hayward earthquake and more recent analogs such

  10. Interferometric method for phase calibration in liquid crystal spatial light modulators using a self-generated diffraction-grating.

    PubMed

    Fuentes, José Luis Martínez; Fernández, Enrique J; Prieto, Pedro M; Artal, Pablo

    2016-06-27

    An auto-referenced interferometric method for calibrating phase modulation of parallel-aligned liquid crystal (PAL) spatial light modulators (SLM) is described. The method is experimentally straightforward, robust, and requires solely of a collimated beam, with no need of additional optics. This method uses the SLM itself to create a tilted plane wave and a reference wave which mutually interfere. These waves are codified by means of a binary diffraction grating and a uniformly distributed gray level area (piston) into the SLM surface. Phase shift for each gray level addressed to the piston section can then be evaluated. Phase modulation on the SLM can also be retrieved with the proposed method over spatially resolved portions of the surface. Phase information obtained with this novel method is compared to other well established calibration procedures, requiring extra elements and more elaborated optical set-ups. The results show a good agreement with previous methods. The advantages of the new method include high mechanical stability, faster performance, and a significantly easier practical implementation. PMID:27410574

  11. SU-E-P-15: Technique Factor Modulation and Reference Plane Air Kerma Rates in Response to Simulated Patient Thickness Variations for a Sample of Current Generation Fluoroscopes

    SciTech Connect

    Wunderle, K; Rakowski, J; Dong, F

    2015-06-15

    Purpose: To evaluate and compare approaches to technique factor modulation and air kerma rates in response to simulated patient thickness variations for four state-of-the-art and one previous-generation interventional fluoroscopes. Methods: A polymethyl methacrylate (PMMA) phantom was used as a tissue surrogate for the purposes of determining fluoroscopic reference plane air kerma rates, kVp, mA, and spectral filtration over a wide range of simulated tissue thicknesses. Data were acquired for each fluoroscopic and acquisition dose curve within a default abdomen or body imaging protocol. Results: The data obtained indicated vendor- and model-specific variations in the approach to technique factor modulation and reference plane air kerma rates across a range of tissue thicknesses. Some vendors have made hardware advances increasing the radiation output capabilities of their fluoroscopes; this was evident in the acquisition air kerma rates. However, in the imaging protocol evaluated, all of the state-of-the-art systems had relatively low air kerma rates in the fluoroscopic low-dose imaging mode as compared to the previous-generation unit. Each of the newest-generation systems also employ copper filtration in the selected protocol in the acquisition mode of imaging; this is a substantial benefit, reducing the skin entrance dose to the patient in the highest dose-rate mode of fluoroscope operation. Conclusion: Understanding how fluoroscopic technique factors are modulated provides insight into the vendor-specific image acquisition approach and provides opportunities to optimize the imaging protocols for clinical practice. The enhanced radiation output capabilities of some of the fluoroscopes may, under specific conditions, may be beneficial; however, these higher output capabilities also have the potential to lead to unnecessarily high dose rates. Therefore, all parties involved in imaging, including the clinical team, medical physicists, and imaging vendors, must work

  12. CATS-ISS_L2O_N-M7.2-V1-05_05kmLay

    Atmospheric Science Data Center

    2016-10-24

    CATS-ISS_L2O_N-M7.2-V1-05_05kmLay Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  13. CATS-ISS_L2O_D-M7.1-V1-05_05kmPro

    Atmospheric Science Data Center

    2016-10-25

    CATS-ISS_L2O_D-M7.1-V1-05_05kmPro Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  14. CATS-ISS_L2O_N-M7.2-V1-05_05kmPro

    Atmospheric Science Data Center

    2016-10-24

    CATS-ISS_L2O_N-M7.2-V1-05_05kmPro Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  15. An inter-laboratory comparison study of the ANSI/BIFMA standard test method M7.1 for furniture

    EPA Science Inventory

    Five laboratories using five different test chambers participated in the study to quantify within- and between-laboratory variability in the measurement of emissions of volatile organic compounds (VOCs) from new commercial furniture test items following ANSI/BIFMA M7.1. Test item...

  16. CATS-ISS_L2O_N-M7.2-V1-03_05kmPro

    Atmospheric Science Data Center

    2016-04-27

    CATS-ISS_L2O_N-M7.2-V1-03_05kmPro Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  17. CATS-ISS_L2O_N-M7.2-V1-04_05kmPro

    Atmospheric Science Data Center

    2016-06-30

    CATS-ISS_L2O_N-M7.2-V1-04_05kmPro Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  18. CATS-ISS_L2O_D-M7.2-V1-04_05kmLay

    Atmospheric Science Data Center

    2016-06-30

    CATS-ISS_L2O_D-M7.2-V1-04_05kmLay Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  19. CATS-ISS_L2O_N-M7.2-V1-03_05kmLay

    Atmospheric Science Data Center

    2016-04-27

    CATS-ISS_L2O_N-M7.2-V1-03_05kmLay Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  20. CATS-ISS_L2O_D-M7.2-V1-03_05kmLay

    Atmospheric Science Data Center

    2016-04-27

    CATS-ISS_L2O_D-M7.2-V1-03_05kmLay The Cloud-Aerosol Transport System (CATS) is a three wavelength, polarization-sensitive lidar that provides ... in the Earth's atmosphere. Project Title:  CATS Discipline:  Clouds Aerosols Version:  ...

  1. CATS-ISS_L2O_N-M7.2-V1-04_05kmLay

    Atmospheric Science Data Center

    2016-06-30

    CATS-ISS_L2O_N-M7.2-V1-04_05kmLay Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  2. CATS-ISS_L2O_D-M7.2-V1-04_05kmPro

    Atmospheric Science Data Center

    2016-06-30

    CATS-ISS_L2O_D-M7.2-V1-04_05kmPro Project Title:  CATS Discipline:  Clouds Aerosols Version:  ... and Order:  ASDC Order Tool Product Browse Tool:  CATS Order Tool OPeNDAP Access:  OPeNDAP Parameters:  ...

  3. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Microwave generation in an optical breakdown plasma created by modulated laser radiation

    NASA Astrophysics Data System (ADS)

    Antipov, A. A.; Grasyuk, Arkadii Z.; Losev, Leonid L.; Soskov, V. I.

    1990-06-01

    It was established that when laser radiation, intensity modulated at a frequency of 2.2 GHz, interacted with an optical breakdown plasma which it had created, a microwave component appeared in the thermal emf of the plasma. The amplitude of the microwave thermal emf reached 0.7 V for a laser radiation intensity of 6 GW/cm2. Laser radiation with λL = 1.06 μm was converted to the microwave range with λmω = 13 cm in the optical breakdown plasma. A microwave signal power of ~ 0.5 W was obtained from a laser power of ~ 5 MW.

  4. Results of a first generation least expensive approach to fission module tests: Non-nuclear testing of a fission system

    NASA Astrophysics Data System (ADS)

    van Dyke, Melissa; Godfroy, Tom; Houts, Mike; Dickens, Ricky; Dobson, Chris; Pederson, Kevin; Reid, Bob; Sena, J. Tom

    2000-01-01

    The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal-hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made. .

  5. Results of a First Generation Propellant Energy Source Module Testing: Non-Nuclear Testing of Fission System

    NASA Technical Reports Server (NTRS)

    VanDyke, Melissa; Godfroy, Tom; Houts, Mike; Dickens, Ricky; Dobson, Chris; Pederson, Kevin; Reid, Bob

    1999-01-01

    The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal- hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made.

  6. All-optical generation of binary phase-coded microwave signal based on cross-polarization modulation in a highly nonlinear fiber.

    PubMed

    Li, Wei; Wang, Wen Ting; Sun, Wen Hui; Zhu, Ning Hua

    2014-03-15

    We report a novel all-optical approach to generate a binary phase-coded microwave signal based on a cross-polarization modulation effect in a highly nonlinear fiber. The carrier frequency of the binary phase-coded microwave signal is widely tunable. Moreover, the precise π phase shift of the microwave signal is independent of the optical power of the control beam. The proposed approach is theoretically analyzed and experimentally verified. For a proof-of-concept demonstration, the binary phase-coded microwave signals with a carrier frequency of 20 GHz at a coding rate of 5  Gb/s and with a carrier frequency of 30 GHz at a coding rate of 7.5  Gb/s are experimentally generated. The pulse compression capability of the system is also evaluated. The measured and simulated results fit well with each other.

  7. FPGA-based rate-adaptive LDPC-coded modulation for the next generation of optical communication systems.

    PubMed

    Zou, Ding; Djordjevic, Ivan B

    2016-09-01

    In this paper, we propose a rate-adaptive FEC scheme based on LDPC codes together with its software reconfigurable unified FPGA architecture. By FPGA emulation, we demonstrate that the proposed class of rate-adaptive LDPC codes based on shortening with an overhead from 25% to 42.9% provides a coding gain ranging from 13.08 dB to 14.28 dB at a post-FEC BER of 10-15 for BPSK transmission. In addition, the proposed rate-adaptive LDPC coding combined with higher-order modulations have been demonstrated including QPSK, 8-QAM, 16-QAM, 32-QAM, and 64-QAM, which covers a wide range of signal-to-noise ratios. Furthermore, we apply the unequal error protection by employing different LDPC codes on different bits in 16-QAM and 64-QAM, which results in additional 0.5dB gain compared to conventional LDPC coded modulation with the same code rate of corresponding LDPC code. PMID:27607718

  8. FPGA-based rate-adaptive LDPC-coded modulation for the next generation of optical communication systems.

    PubMed

    Zou, Ding; Djordjevic, Ivan B

    2016-09-01

    In this paper, we propose a rate-adaptive FEC scheme based on LDPC codes together with its software reconfigurable unified FPGA architecture. By FPGA emulation, we demonstrate that the proposed class of rate-adaptive LDPC codes based on shortening with an overhead from 25% to 42.9% provides a coding gain ranging from 13.08 dB to 14.28 dB at a post-FEC BER of 10-15 for BPSK transmission. In addition, the proposed rate-adaptive LDPC coding combined with higher-order modulations have been demonstrated including QPSK, 8-QAM, 16-QAM, 32-QAM, and 64-QAM, which covers a wide range of signal-to-noise ratios. Furthermore, we apply the unequal error protection by employing different LDPC codes on different bits in 16-QAM and 64-QAM, which results in additional 0.5dB gain compared to conventional LDPC coded modulation with the same code rate of corresponding LDPC code.

  9. Thermal study of payload module for the next-generation infrared space telescope SPICA in risk mitigation phase

    NASA Astrophysics Data System (ADS)

    Shinozaki, Keisuke; Sato, Yoichi; Sawada, Kenichiro; Ando, Makiko; Sugita, Hiroyuki; Yamawaki, Toshihiko; Mizutani, Tadahito; Komatsu, Keiji; Okazaki, Shun; Ogawa, Hiroyuki; Nakagawa, Takao; Matsuhara, Hideo; Takada, Makoto; Okabayashi, Akinobu; Tsunematsu, Shoji; Narasaki, Katsuhiro

    2014-08-01

    The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is a pre-project of JAXA in collaboration with ESA to be launched around 2025. The SPICA mission is to be launched into a halo orbit around the second Lagrangian point in the Sun-Earth system, which allows us to use effective radiant cooling in combination with a mechanical cooling system in order to cool a 3m large IR telescope below 6K. The use of 4K / 1K-class Joule-Thomson coolers is proposed in order to cool the telescope and provide a 4K / 1K temperature region for Focal Plane Instruments (FPIs). This paper introduces details of the thermal design study for the SPICA payload module in the Risk-Mitigation-Phase (RMP), in which the activity is focused on mitigating the mission's highest risks. As the result of the RMP activity, most of all the goals have been fully satisfied and the thermal design of the payload module has been dramatically improved.

  10. Modulation of Smad signaling by non-TGFβ components in myofibroblast generation during wound healing in corneal stroma.

    PubMed

    Saika, Shizuya; Yamanaka, Osamu; Okada, Yuka; Sumioka, Takayoshi

    2016-01-01

    Corneal scarring/fibrosis disturbs normal transparency and curvature of the tissue and thus impairs vision. The lesion is characterized by appearance of myofibroblasts, the key player of the fibrogenic reaction, and excess accumulation of extracellular matrix. Inflammatory/fibrogenic growth factors or cytokines expressed in inflammatory cells that infiltrate into injured tissues play a pivotal role in fibrotic tissue formation. In this article the pathogenesis of fibrosis/scarring in the corneal stroma is reviewed focusing on the roles of myofibroblast, the key player in corneal stromal wound healing and fibrosis, and cytoplasmic signals activated by the fibrogenic cytokine, transforming growth factor β (TGFβ). Although it is established that TGFβ/Smad signal is essential to the process of keratocyte-myofibroblast transformation in a healing corneal stroma post-injury. This article emphasizes the involvement of non-TGFβ molecular mechanisms in modulating Smad signal. We focus on the roles of matricellular proteins, i.e., osteopontin and tenascin C, and as cellular components, the roles of transient receptor potential (TRP) cation channel receptors are discussed. Our intent is to draw attention to the possibility of signal transduction cascade modulation (e.g., Smad signal and mitogen-activated protein kinases, by gene transfer and other related technology) as being beneficial in a clinical setting to reduce or even prevent corneal stromal tissue fibrosis/scarring and inflammation.

  11. Fault-Zone Trapped Waves from Aftershocks of the M7.2 Darfield and M6.3 Christchurch Earthquake Sequence for Document of Subsurface Damage Zones

    NASA Astrophysics Data System (ADS)

    Li, Y.; De Pascale, G. P.; Gravley, D.; Cherrington, J.; Alvarez, M. G.

    2011-12-01

    The M6.3 Christchurch earthquake struck the Canterbury region in NZ's South Island on 22 February 2011, following ~6 months after the Sept. 4, 2010 M7.1 Darfield earthquake in the same region. It has generated a significant series of aftershocks, many of which are considered big for a M6.3 earthquake. It is not know clearly whether the later M6.3 event is technically an aftershock because of its relationship to the ongoing activity since September last year, or it is a separate event, given its location on a separate fault system, a previously unknown blind fault line running 17 km south of Christchurch. In order to study the complicated subsurface structure of the damage zones caused by this sequence of earthquakes in NZ, under the support of NSF-RAPID Program, we deployed 12 PASSCAL seismographs in two ~300-m long seismic lines across the Greendale fault where the horizontal right-lateral slip of 4.5 m and vertical slip of 1.6 m were caused by the 2010 M7.2 Darfield earthquake and the aftershock zone of the M6.3 Christchurch earthquake, respectively, to record fault-zone trapped waves (FZTWs) generated by aftershocks, starting from May 5th, 2011. We have recorded the data for ~300 M>3 aftershocks with good locations and more than ~1000 small events not located yet but with good signal-to-noise ratio at these two arrays, including M5.3, M6, M5.4, M5.1 aftershocks with their clustered events at depths of 10-15 km. Preliminary examination of the waveform data shows FZTWs clearly at stations located within the 50-75-m wide rupture zone with high density of en-echelon cracks on the ground surface along the Greendale fault. 3-D finite-difference simulations of these FZTWs show a distinct low-velocity zone (LVZ) at seismogenic depth, indicating that the Greendale fault has undergone strong dynamic stresses and pervasive cracking during the 2010 M7.2 Darfield earthquake. We interpret this LVZ as being a remnant of damage zone in dynamic ruptures that accumulated damage

  12. Comparison of advanced DSP techniques for spectrally efficient Nyquist-WDM signal generation using digital FIR filters at transmitters based on higher-order modulation formats

    NASA Astrophysics Data System (ADS)

    Weng, Yi; Wang, Junyi; Pan, Zhongqi

    2016-02-01

    To support the ever-increasing demand for high-speed optical communications, Nyquist spectral shaping serves as a promising technique to improve spectral efficiency (SE) by generating near-rectangular spectra with negligible crosstalk and inter-symbol interference in wavelength-division-multiplexed (WDM) systems. Compared with specially-designed optical methods, DSP-based electrical filters are more flexible as they can generate different filter shapes and modulation formats. However, such transmitter-side pre-filtering approach is sensitive to the limited taps of finite-impulse-response (FIR) filter, for the complexity of the required DSP and digital-to-analog converter (DAC) is limited by the cost and power consumption of optical transponder. In this paper, we investigate the performance and complexity of transmitter-side FIR-based DSP with polarization-division-multiplexing (PDM) high-order quadrature-amplitude-modulation (QAM) formats. Our results show that Nyquist 64-QAM, 16-QAM and QPSK WDM signals can be sufficiently generated by digital FIR filters with 57, 37, and 17 taps respectively. Then we explore the effects of the required spectral pre-emphasis, bandwidth and resolution on the performance of Nyquist-WDM systems. To obtain negligible OSNR penalty with a roll-off factor of 0.1, two-channel-interleaved DAC requires a Gaussian electrical filter with the bandwidth of 0.4-0.6 times of the symbol rate for PDM-64QAM, 0.35-0.65 times for PDM-16QAM, and 0.3-0.8 times for PDM-QPSK, with required DAC resolutions as 8, 7, 6 bits correspondingly. As a tradeoff, PDM-64QAM can be a promising candidate for SE improvement in next-generation optical metro networks.

  13. Rupture process of the 2005 M7.2 Miyagi-Oki, NE Japan, earthquake inferred from coseismic slip and aftershock distributions, and its comparison with the 1978 M7.4 Miyagi-Oki earthquake

    NASA Astrophysics Data System (ADS)

    Okada, T.; Yaginuma, T.; Umino, N.; Kono, T.; Matsuzawa, T.; Kita, S.; Hasegawa, A.

    2005-12-01

    A large (M7.2) interplate earthquake occurred on 16 August 2005 in the Miyagi-Oki region, NE Japan. In this area, large interplate earthquakes with magnitude of ~M7.5 occurred repeatedly at a recurrence interval of ~37 yrs. Base on this recurrence of large earthquakes, the Headquarters of Earthquake Research Promotion of the Japanese government released the information of high probability (~50 percents within 10 years from now) of the impending earthquake to the public. To compare the aftershock distribution of the 2005 Miyagi-Oki earthquake with that of the previous (1978) Miyagi-Oki earthquake (M7.4), we relocated hypocenters of the aftershocks using double-difference method (Waldhauser and Ellsworth, 2000). Spatial extent of the aftershock area of the 2005 event is 80km and 40km in dip and strike directions, respectively. High aftershock activity was observed in the central part of the aftershock area, which is located to north-west of the mainshock hypocenter. The aftershock area of the 2005 event is overlapped with the southern/south-eastern part of that of the 1978 event. Locations of the aftershock clusters of the 2005 event correspond with those of the 1978 event and those of the background seismicity. We estimated coseismic slip distribution of the 2005 event by seismic waveform inversion by a method of Yagi et al. (2004). Obtained coseismic slipped area of the 2005 event extended mainly to the dip (northwest) direction, which is almost correspond with the area with high aftershock activity, and also partly overlapped with that of the 1978 event (Yamanaka & Kikuchi, 2004). These observations suggest that the spatial seismicity pattern on the plate boundary in subduction zone persists in time and the 2005 event have ruptured one of the asperities which caused the 1978 M7.4 event.

  14. Low Fidelity Imitation of Atypical Biological Kinematics in Autism Spectrum Disorders Is Modulated by Self-Generated Selective Attention.

    PubMed

    Hayes, Spencer J; Andrew, Matthew; Elliott, Digby; Gowen, Emma; Bennett, Simon J

    2016-02-01

    We examined whether adults with autism had difficulty imitating atypical biological kinematics. To reduce the impact that higher-order processes have on imitation we used a non-human agent model to control social attention, and removed end-state target goals in half of the trials to minimise goal-directed attention. Findings showed that only neurotypical adults imitated atypical biological kinematics. Adults with autism did, however, become significantly more accurate at imitating movement time. This confirmed they engaged in the task, and that sensorimotor adaptation was self-regulated. The attentional bias to movement time suggests the attenuation in imitating kinematics might be a compensatory strategy due to deficits in lower-level visuomotor processes associated with self-other mapping, or selective attention modulated the processes that represent biological kinematics.

  15. Modulated exponential films generated by surface acoustic waves and their role in liquid wicking and aerosolization at a pinned drop.

    PubMed

    Taller, Daniel; Go, David B; Chang, Hsueh-Chia

    2013-05-01

    The exponentially decaying acoustic pressure of scattered surface acoustic waves (SAWs) at the contact line of a liquid film pinned to filter paper is shown to sustain a high curvature conic tip with micron-sized modulations whose dimension grows exponentially from the tip. The large negative capillary pressure in the film, necessary for offsetting the large positive acoustic pressure at the contact line, also creates significant negative hydrodynamic pressure and robust wicking action through the paper. An asymptotic analysis of this intricate pressure matching between the quasistatic conic film and bulk drop shows that the necessary SAW power to pump liquid from the filter paper and aerosolize, expressed in terms of the acoustic pressure scaled by the drop capillary pressure, grows exponentially with respect to twice the acoustic decay constant multiplied by the drop length, with a universal preexponential coefficient. Global rapid aerosolization occurs at a SAW power twice as high, beyond which the wicking rate saturates. PMID:23767617

  16. Crystallization and preliminary crystallographic analysis of tRNA (m(7)G46) methyltransferase from Escherichia coli.

    PubMed

    Liu, Qi; Gao, Yang; Yang, Weili; Zhou, Huihao; Gao, Yongxiang; Zhang, Xiao; Teng, Maikun; Niu, Liwen

    2008-08-01

    Transfer RNA (tRNA) (m(7)G46) methyltransferase (TrmB) belongs to the Rossmann-fold methyltransferase (RFM) family and uses S-adenosyl-L-methionine (SAM) as the methyl-group donor to catalyze the formation of N(7)-methylguanosine (m(7)G) at position 46 in the variable loop of tRNAs. After attempts to crystallize full-length Escherichia coli TrmB (EcTrmB) failed, a truncated protein lacking the first 32 residues of the N-terminus but with an additional His(6) tag at the C-terminus was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 3350 (PEG 3350) as precipitant at 283 K. An X-ray diffraction data set was collected using a single flash-cooled crystal that belonged to space group P2(1).

  17. Crystallization and preliminary crystallographic analysis of tRNA (m7G46) methyltransferase from Escherichia coli

    PubMed Central

    Liu, Qi; Gao, Yang; Yang, Weili; Zhou, Huihao; Gao, Yongxiang; Zhang, Xiao; Teng, Maikun; Niu, Liwen

    2008-01-01

    Transfer RNA (tRNA) (m7G46) methyltransferase (TrmB) belongs to the Rossmann-fold methyltransferase (RFM) family and uses S-adenosyl-l-methionine (SAM) as the methyl-group donor to catalyze the formation of N 7-­methylguanosine (m7G) at position 46 in the variable loop of tRNAs. After attempts to crystallize full-length Escherichia coli TrmB (EcTrmB) failed, a truncated protein lacking the first 32 residues of the N-terminus but with an additional His6 tag at the C-terminus was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 3350 (PEG 3350) as precipitant at 283 K. An X-ray diffraction data set was collected using a single flash-cooled crystal that belonged to space group P21. PMID:18678947

  18. Preparation of Functional, Fluorescently Labeled mRNA Capped with Anthraniloyl-m(7)GpppG.

    PubMed

    Domashevskiy, Artem V; Rodriguez, David J; Gunawardana, Dilantha; Goss, Dixie J

    2016-01-01

    Fluorescent mRNA molecules offer a wide range of applications for studying capping/decapping reactions, translation, and other biophysical studies. Furthermore, fluorescent tags prove invaluable for tracking RNA molecules in cells. Here, we describe an efficient synthesis of a fluorescent cap analog, anthranioyl-GTP, its purification, and in vitro cap labeling of transcribed mRNA catalyzed by the recombinant vaccinia capping enzyme to produce anthranioyl-m(7)GpppG-capped RNA. PMID:27236792

  19. Infrasound associated with the deep M 7.3 northeastern China earthquake of June 28, 2002

    NASA Astrophysics Data System (ADS)

    Che, Il-Young; Kim, Geunyoung; Pichon, Alexis Le

    2013-02-01

    On 28 June, 2002, a deep-focus (566 km) earthquake with a moment magnitude of 7.3 occurred in the China-Russia-North Korea border region. Despite its deep focus, the earthquake produced an infrasound signal that was observed by the remote infrasound array (CHNAR), 682 km from the epicenter, in South Korea. Coherent infrasound signals were detected sequentially at the receiver, with different arrival times and azimuths indicating that the signals were generated both near the epicenter and elsewhere. On the basis of the azimuth, arrival time measurements, and atmospheric ray simulation results, the source area of the infrasonic signals that arrived earlier were located along the eastern coastal areas of North Korea and Russia, whereas later signals were sourced throughout Japan. The geographically-constrained, and discrete, distribution of the sources identified is explained by infrasound propagation effects caused by a westward zonal wind that was active when the event occurred. The amplitude of the deep quake's signal was equivalent to that of a shallow earthquake with a magnitude of approximately 5. This study expands the breadth of seismically-associated infrasound to include deep earthquakes, and also supports the possibility that infrasound measurements could help determine the depth of earthquakes.

  20. Evidence of α-, β- and γ-HCH mixture aerobic degradation by the native actinobacteria Streptomyces sp. M7.

    PubMed

    Sineli, P E; Tortella, G; Dávila Costa, J S; Benimeli, C S; Cuozzo, S A

    2016-05-01

    The organochlorine insecticide γ-hexachlorocyclohexane (γ-HCH, lindane) and its non-insecticidal α- and β-isomers continue to pose serious environmental and health concerns, although their use has been restricted or completely banned for decades. In this study we report the first evidence of the growth ability of a Streptomyces strain in a mineral salt medium containing high doses of α- and β-HCH (16.6 mg l(-1)) as a carbon source. Degradation of HCH isomers by Streptomyces sp. M7 was investigated after 1, 4, and 7 days of incubation, determining chloride ion release, and residues in the supernatants by GC with µECD detection. The results show that both the α- and β-HCH isomers were effectively metabolized by Streptomyces sp. M7, with 80 and 78 % degradation respectively, after 7 days of incubation. Moreover, pentachlorocyclohexenes and tetrachlorocyclohexenes were detected as metabolites. In addition, the formation of possible persistent compounds such as chlorobenzenes and chlorophenols were studied by GC-MS, while no phenolic compounds were detected. In conclusion, we have demonstrated for the first time that Streptomyces sp. M7 can degrade α- and β-isomers individually or combined with γ-HCH and could be considered as a potential agent for bioremediation of environments contaminated by organochlorine isomers. PMID:27038951

  1. Evidence of α-, β- and γ-HCH mixture aerobic degradation by the native actinobacteria Streptomyces sp. M7.

    PubMed

    Sineli, P E; Tortella, G; Dávila Costa, J S; Benimeli, C S; Cuozzo, S A

    2016-05-01

    The organochlorine insecticide γ-hexachlorocyclohexane (γ-HCH, lindane) and its non-insecticidal α- and β-isomers continue to pose serious environmental and health concerns, although their use has been restricted or completely banned for decades. In this study we report the first evidence of the growth ability of a Streptomyces strain in a mineral salt medium containing high doses of α- and β-HCH (16.6 mg l(-1)) as a carbon source. Degradation of HCH isomers by Streptomyces sp. M7 was investigated after 1, 4, and 7 days of incubation, determining chloride ion release, and residues in the supernatants by GC with µECD detection. The results show that both the α- and β-HCH isomers were effectively metabolized by Streptomyces sp. M7, with 80 and 78 % degradation respectively, after 7 days of incubation. Moreover, pentachlorocyclohexenes and tetrachlorocyclohexenes were detected as metabolites. In addition, the formation of possible persistent compounds such as chlorobenzenes and chlorophenols were studied by GC-MS, while no phenolic compounds were detected. In conclusion, we have demonstrated for the first time that Streptomyces sp. M7 can degrade α- and β-isomers individually or combined with γ-HCH and could be considered as a potential agent for bioremediation of environments contaminated by organochlorine isomers.

  2. Salvianolic Acid B Inhibits Aβ Generation by Modulating BACE1 Activity in SH-SY5Y-APPsw Cells

    PubMed Central

    Tang, Ying; Huang, Dan; Zhang, Mei-Hua; Zhang, Wen-Sheng; Tang, Yu-Xin; Shi, Zheng-Xiang; Deng, Li; Zhou, Dai-Han; Lu, Xin-Yi

    2016-01-01

    Alzheimer’s disease (AD) is a neurodegenerative disease in humans. The accumulation of amyloid-β (Aβ) plays a critical role in the pathogenesis of AD. Previous studies indicated that Salvianolic acid B (SalB) could ameliorate Aβ-induced memory impairment. However, whether SalB could influence the generation of Aβ is unclear. Here, we show that SalB (25, 50, or 100 µM) reduces the generation of Aβ40 and Aβ42 in culture media by decreasing the protein expressions of BACE1 and sAPPβ in SH-SY5Y-APPsw cells. Meanwhile, SalB increases the levels of ADAM10 and sAPPα in the cells. However, SalB has no impact on the protein expressions of APP and PS1. Moreover, SalB attenuates oxidative stress and inhibits the activity of GSK3β, which might be related to the suppression of BACE1 expression and amyloidogenesis. Our study suggests that SalB is a promising therapeutic agent for AD by targeting Aβ generation. PMID:27258307

  3. 7-methylguanosine diphosphate (m(7)GDP) is not hydrolyzed but strongly bound by decapping scavenger (DcpS) enzymes and potently inhibits their activity.

    PubMed

    Wypijewska, Anna; Bojarska, Elzbieta; Lukaszewicz, Maciej; Stepinski, Janusz; Jemielity, Jacek; Davis, Richard E; Darzynkiewicz, Edward

    2012-10-01

    Decapping scavenger (DcpS) enzymes catalyze the cleavage of a residual cap structure following 3' → 5' mRNA decay. Some previous studies suggested that both m(7)GpppG and m(7)GDP were substrates for DcpS hydrolysis. Herein, we show that mononucleoside diphosphates, m(7)GDP (7-methylguanosine diphosphate) and m(3)(2,2,7)GDP (2,2,7-trimethylguanosine diphosphate), resulting from mRNA decapping by the Dcp1/2 complex in the 5' → 3' mRNA decay, are not degraded by recombinant DcpS proteins (human, nematode, and yeast). Furthermore, whereas mononucleoside diphosphates (m(7)GDP and m(3)(2,2,7)GDP) are not hydrolyzed by DcpS, mononucleoside triphosphates (m(7)GTP and m(3)(2,2,7)GTP) are, demonstrating the importance of a triphosphate chain for DcpS hydrolytic activity. m(7)GTP and m(3)(2,2,7)GTP are cleaved at a slower rate than their corresponding dinucleotides (m(7)GpppG and m(3)(2,2,7)GpppG, respectively), indicating an involvement of the second nucleoside for efficient DcpS-mediated digestion. Although DcpS enzymes cannot hydrolyze m(7)GDP, they have a high binding affinity for m(7)GDP and m(7)GDP potently inhibits DcpS hydrolysis of m(7)GpppG, suggesting that m(7)GDP may function as an efficient DcpS inhibitor. Our data have important implications for the regulatory role of m(7)GDP in mRNA metabolic pathways due to its possible interactions with different cap-binding proteins, such as DcpS or eIF4E.

  4. High-efficiency micro-energy generation based on free-carrier-modulated ZnO:N piezoelectric thin films

    SciTech Connect

    Lee, Eunju; Park, Jaedon; Yim, Munhyuk; Jeong, Sangbeom; Yoon, Giwan

    2014-05-26

    The free-carrier-modulated ZnO:N thin film-based flexible nanogenerators (NZTF-FNGs) are proposed and experimentally demonstrated. The suggested flexible nanogenerators (FNGs) are fabricated using N-doped ZnO thin films (NZTFs) as their piezoelectric active elements, which are deposited by a radio frequency magnetron sputtering technique with an N{sub 2}O reactive gas as an in situ dopant source. Considerable numbers of N atoms are uniformly incorporated into NZTFs overall during their growth, which would enable them to significantly compensate the unintentional background free electron carriers both in the bulk and at the surface of ZnO thin films (ZTFs). This N-doping approach is found to remarkably enhance the performance of NZTF-FNGs, which shows output voltages that are almost two orders of magnitude higher than those of the conventionally grown ZnO thin film-based FNGs. This is believed to be a result of both substantial screening effect suppression in the ZTF bulk and more reliable Schottky barrier formation at the ZTF interfaces, which is all mainly caused by the N-compensatory doping process. Furthermore, the NZTF-FNGs fabricated are verified via charging tests to be suitable for micro-energy harvesting devices.

  5. Seismic quiescence precursors to two M7 earthquakes on Sakhalin Island, measured by two methods

    NASA Astrophysics Data System (ADS)

    Wyss, Max; Sobolev, Gennady; Clippard, James D.

    2004-08-01

    Two large earthquakes occurred during the last decade on Sakhalin Island, the M w 7.6 Neftegorskoe earthquake of 27 May 1995 and the M w 6.8 Uglegorskoe earthquake of 4 August 2000, in the north and south of the island, respectively. Only about five seismograph stations record earthquakes along the 1000 km, mostly strike-slip plate boundary that transects the island from north to south. In spite of that, it was possible to investigate seismicity patterns of the last two to three decades quantitatively. We found that in, and surrounding, their source volumes, both of these main shocks were preceded by periods of pronounced seismic quiescence, which lasted 2.5 ± 0.5 years. The distances to which the production of earthquakes was reduced reached several hundred kilometers. The probability that these periods of anomalously low seismicity occurred by chance is estimated to be about 1% to 2%. These conclusions were reached independently by the application of two methods, which are based on different approaches. The RTL-algorithm measures the level of seismic activity in moving time windows by counting the number of earthquakes, weighted by their size, and inversely weighted by their distance, in time and space from the point of observation. The Z-mapping approach measures the difference of the seismicity rate, within moving time windows, to the background rate by the standard deviate Z. This generates an array of comparisons that cover all of the available time and space, and that can be searched for all anomalous departures from the normal seismicity rate. The RTL-analysis was based on the original catalog with K-classes measuring the earthquake sizes; the Z-mapping was based on the catalog with Ktransformed into magnitudes. The RTL-analysis started with data from 1980, the Z-mapping technique used the data from 1974 on. In both methods, cylindrical volumes, centered at the respective epicenters, were sampled. The Z-mapping technique additionally investigated the

  6. Mesenchymal Stem Cells Ability to Generate Traction Stress in Response to Substrate Stiffness is Modulated by the Changing Extracellular Matrix Composition of the Heart During Development

    PubMed Central

    Gershlak, Joshua R.; Resnikoff, Joshua IN; Sullivan, Kelly E; Williams, Corin; Wang, Raymond M.; Black, Lauren D.

    2013-01-01

    In this study we present a novel method for studying cellular traction force generation and mechanotransduction in the context of cardiac development. Rat hearts from three distinct stage of development (fetal, neonatal and adult) were isolated, decellularized and characterized via mechanical testing and protein compositional analysis. Stiffness increased ~2 fold between fetal and neonatal time points but not between neonatal and adult. Composition of structural extracellular matrix (ECM) proteins was significantly different between all three developmental ages. ECM that was solubilized via pepsin digestion was cross-linked into polyacrylamide gels of varying stiffness and traction force microscopy was used to assess the ability of mesenchymal stem cells (MSCs) to generate traction stress against the substrates. The response to increasing stiffness was significantly different depending on the developmental age of the ECM. An investigation into early cardiac differentiation of MSCs demonstrated a dependence of the level of expression of early cardiac transcription factors on the composition of the complex ECM. In summary, this study found that complex ECM composition plays an important role in modulating a cell’s ability to generate traction stress against a substrate, which is a significant component of mechanotransductive signaling. PMID:23994333

  7. MODULATION OF LOW ENERGY BEAM TO GENERATE PREDEFINED BUNCH TRAINS FOR THE NSLS-II TOP-OFF INJECTION

    SciTech Connect

    Wang, G.M.; Cheng, W.X.; Shaftan, T.; Fliller, R.; Heese, R.; Rose, J.

    2011-03-28

    The NSLS II linac will produce a bunch train, 80-150 bunches long with 2 ns bunch spacing. Having the ability to tailor the bunch train can lead to the smaller bunch to bunch charge variation in the storage ring. A stripline is planned to integrate into the linac baseline to achieve this tailoring. The stripline must have a fast field rise and fall time to tailor each bunch. The beam dynamics is minimally affected by including the extra space for the stripline. This paper discusses the linac beam dynamics with stripline, and the optimal design of the stripline. A stripline is to be integrated in the linac to match the storage ring uniform bunch charge requirement, which simplifies the gun pulser electronics and looses the edge uniform requirement. It is located at low energy to lower the stripline power supply requirement and limit the dumped electron radiation. By turning off the stripline, the beam dynamics through linac is comparable with the baseline design. More advanced ideas can be explored. If a DC corrector along with the stripline is used, the core bunch trains gets kick from the stripline while the head and the tail of bunch train just gets a DC kick. The stripline power supply waveform is a single flat top waveform with fast rise and drop and the pulse length is {approx}200 ns long or 100 bunches, which may be easier from the power supply view point. We are also considering the bunch by bunch charge manipulation to match the storage ring uniform bunch charge distribution requirement. By modulating the flat top waveform at 250 MHz with adjustable amplitude, each the bunch center is either at 45 degree or 135 degree. Only the head or tail of the bunch is trimmed out. Although each bunch center deviation from idea center is very different at low energy, it is gradually minimized with beam energy increase.

  8. Modulating optical rectification, second and third harmonic generation of doped quantum dots: Interplay between hydrostatic pressure, temperature and noise

    NASA Astrophysics Data System (ADS)

    Ganguly, Jayanta; Saha, Surajit; Bera, Aindrila; Ghosh, Manas

    2016-10-01

    We examine the profiles of optical rectification (OR), second harmonic generation (SHG) and third harmonic generation (THG) of impurity doped QDs under the combined influence of hydrostatic pressure (HP) and temperature (T) in presence and absence of Gaussian white noise. Noise has been incorporated to the system additively and multiplicatively. In order to study the above nonlinear optical (NLO) properties the doped dot has been subjected to a polarized monochromatic electromagnetic field. Effect of application of noise is nicely reflected through alteration of peak shift (blue/red) and variation of peak height (increase/decrease) of above NLO properties as temperature and pressure are varied. All such changes again sensitively depends on mode of application (additive/multiplicative) of noise. The remarkable influence of interplay between noise strength and its mode of application on the said profiles has also been addressed. The findings illuminate fascinating role played by noise in tuning above NLO properties of doped QD system under the active presence of both hydrostatic pressure and temperature.

  9. A 17-year oscillation in cancer mortality birth cohorts on three continents - synchrony to cosmic ray modulations one generation earlier.

    PubMed

    Juckett, David A

    2009-11-01

    Cross-generational effects (grandmother effects) associated with epigenetic imprinting, environmental exposures, and lifestyle choices are beginning to be explored by various investigators. The possibility that low-level background radiation can be a driver of such effects has been suggested previously and is explored further in this study. Age-period-cohort analysis was performed on United States (US), United Kingdom (UK), and Australian (AU) female breast cancer mortality of the twentieth century, as well as on UK female total cancer mortality, to extract the high-frequency oscillations in the birth cohort time series. US fetal and infant congenital mortality were examined to extend the birth cohorts to modern times. A approximately 17-year cycle was detected in all birth cohort series, which spanned approximately 180 years from 1820 to 2000. This suggests a global, environmental cause. To mimic previous work in examining a possible link to cosmic radiation, the 17- to 18-year cycles of the cosmogenic nuclide (14)C, the sunspot double-cycle, neutron monitors, and a compilation of ground-based magnetic field observations were examined in the birth cohort and germ cell cohort time frames. Evidence is presented that optimal alignments with extraterrestrial oscillations occur in the time frame of the germ-cell cohort, one generation before the birth cohorts. Furthermore, the alignment is optimized by accounting for the changes in the maternal age distribution over time. These findings have potential importance to the mechanisms of disease as well as species adaptation and evolution.

  10. Coseismic Slip Model of the M 7.8 2015 Nepal Earthquake and its M 7.2 Aftershock from Joint Inversion of InSAR and GPS Data

    NASA Astrophysics Data System (ADS)

    Cheloni, D.; Tolomei, C.; Bignami, C.; D'Agostino, N.; Atzori, S.

    2015-12-01

    We derived a coseismic slip model for the M 7.8 2015 Nepal earthquake on the basis of radar line-of-sight displacements retrieved from RADARSAT, ALOS and SENTINEL interferograms and GPS data. We use the surface trace of the Main Himalayan Thrust (MHT) and moment tensor solution to approximate the earthquake rupture plane with a planar thrust fault having a strike of ~295° and a dip of ~10°. Our rupture model suggests that the slip area is about 120 x 50 km, with the most of the moment release limited to a depth between 10-20 km. Therefore the earthquake did not reach the surface suggesting a marked shallow slip deficit in the slip depth distribution. The earthquake released a seismic moment of 7.88E+20 Nm, corresponding to a Mw 7.88. Adopting the same fault geometry we also estimated the slip distribution related to the M 7.2 aftershock that occurred near the eastern end of the main coseismic asperity. The aftershock rupture model shows a more compact slip area of about 30 x 30 km, releasing a moment of 5.49E+19 Nm and corresponding to a Mw 7.13. We calculated the static stress changes on the assumed fault plane due to the mainshock. The result suggests loading of the fault around the main coseismic patch where indeed most of the aftershocks, comprising the M 7.2 event, were primarily distributed. Future researches will be focused on the up-dip locked portions of the MHT that did not break during the 25 April 2015 Nepal earthquake and the monitoring of the post-seismic phase by means of InSAR and GPS data.

  11. Global study of great (M>= 7) deep focus seismic events having regard to the May 24, 2013 Mw 8.3 earthquake the Sea of Okhotsk, Russia

    NASA Astrophysics Data System (ADS)

    Varga, Peter; Rogozhin, Evgeny; Süle, Bálint; Andreeva, Nadezda

    2014-05-01

    Distribution of great seismic events M >= 7.0 and consequently the released seismic energy along the Earth radius is of bimodal character. 90% of the great seismic events, which are responsible for the most of energy released, occur relatively close to the Earth's surface, at an average depth of 50 km. The vast majority of remaining 10% is associated with seismic events that occur very deep, an average of 580-590 km, above the border between transition zone and lower mantle (660 km). These very deep earthquakes (depth >= 500 km) differ significantly from the shallow events. For the study of the distribution of M >= 7.0 earthquakes and their radiated energy a catalogue was completed for the time-interval between 1900 and 2013. Examination of the source zones in which both shallow and deep M >= 7.0 earthquakes occur shows that linear distribution of deep earthquakes is considerably shorter than that found for the shallow earthquakes, which determine the length of the zone. The position of very deep (≥ 500 km) earthquakes foci show where the down going lithosperic plates conflict with the upper boundary of lower mantle, and where they probably cross it. This passage generates compression - elongation inside the slab. A comparison of temporal distribution of shallow and deep seismic events of a given source zone suggests that there is no direct relationship in the distribution of these two different earthquake activities. The largest of these great deep earthquakes, the May 24, 2013 Mw 8.3 earthquake the Sea of Okhotsk, was preceded by an earthquake swarm, which consists 58 M >= 5 events and occurred between May 15 and 24, 2013 in the higher part of the sinking slab east of Kamchatka. The aftershock activity after the Okhotsk Sea earthquake was moderate: twelve events with magnitudes above M 4 were observed till June 27. These events determine a fault area (2.64x104 km2) similar to the case of a shallow M 8.3 event. The effect of Okhotsk Sea was felt throughout

  12. Rupture process of the M 7.9 Denali fault, Alaska, earthquake: Subevents, directivity, and scaling of high-frequency ground motions

    USGS Publications Warehouse

    Frankel, A.

    2004-01-01

    Displacement waveforms and high-frequency acceleration envelopes from stations at distances of 3-300 km were inverted to determine the source process of the M 7.9 Denali fault earthquake. Fitting the initial portion of the displacement waveforms indicates that the earthquake started with an oblique thrust subevent (subevent # 1) with an east-west-striking, north-dipping nodal plane consistent with the observed surface rupture on the Susitna Glacier fault. Inversion of the remainder of the waveforms (0.02-0.5 Hz) for moment release along the Denali and Totschunda faults shows that rupture proceeded eastward on the Denali fault, with two strike-slip subevents (numbers 2 and 3) centered about 90 and 210 km east of the hypocenter. Subevent 2 was located across from the station at PS 10 (Trans-Alaska Pipeline Pump Station #10) and was very localized in space and time. Subevent 3 extended from 160 to 230 km east of the hypocenter and had the largest moment of the subevents. Based on the timing between subevent 2 and the east end of subevent 3, an average rupture velocity of 3.5 km/sec, close to the shear wave velocity at the average rupture depth, was found. However, the portion of the rupture 130-220 km east of the epicenter appears to have an effective rupture velocity of about 5.0 km/ sec, which is supershear. These two subevents correspond approximately to areas of large surface offsets observed after the earthquake. Using waveforms of the M 6.7 Nenana Mountain earthquake as empirical Green's functions, the high-frequency (1-10 Hz) envelopes of the M 7.9 earthquake were inverted to determine the location of high-frequency energy release along the faults. The initial thrust subevent produced the largest high-frequency energy release per unit fault length. The high-frequency envelopes and acceleration spectra (>0.5 Hz) of the M 7.9 earthquake can be simulated by chaining together rupture zones of the M 6.7 earthquake over distances from 30 to 180 km east of the

  13. UWB and 60-GHz RF generation and transmission over WDM-PON based on bidirectional asymmetric polarization modulation and frequency multiplication

    NASA Astrophysics Data System (ADS)

    Liu, Weilin; Yao, Jianping

    2013-10-01

    A novel scheme to simultaneously provide UWB, 60-GHz millimeter-wave (mmW), and baseband services over a wavelength division multiplexing (WDM) passive optical network (PON) is proposed and demonstrated. In the proposed system, an OOK Gaussian pulse signal is modulated on the optical carrier and then converted to an OOK UWB impulse signal at an edge filter, a baseband signal and a 30-GHz signal are then modulated on the same optical carrier. By employing polarization multiplex technique, the UWB and baseband signal will have orthogonal polarization directions and the spectrum interference between the two signals is avoided. By suppressing the optical carrier, a frequencydoubled mmW signal at 60 GHz is generated by beating the two 1st order sidebands at a photodetector (PD). Error-free transmission of a UWB signal at 2.5 Gbps and a wired baseband signal at 2.5 and 5 Gbps over a 25-km single-mode fiber (SMF) is achieved. A frequency-doubled mmW signal at 60 GHz is also obtained.

  14. Efficient multibeam large-angle nonmechanical laser beam steering from computer-generated holograms rendered on a liquid crystal spatial light modulator.

    PubMed

    Lindle, James R; Watnik, Abbie T; Cassella, Vincent A

    2016-06-01

    Multibeam large-angle beam steering is demonstrated in the visible spectral region by imprinting computer-generated holographic Fresnel zone plates on a liquid crystal spatial light modulator (SLM) configured as the first element of a telescope. The position and intensity of each beam are controlled independently. The laser beam is steered over a ±37° field of regard, with the power in the beam at 37° being greater than 50% of the on-axis power. The power delivered on axis for a single beam was 48% of the power incident on the SLM. The beam profile remained Gaussian over the full steering range, and the on-axis beam divergence is 2.1 mrad. PMID:27411184

  15. Next-generation proteasome inhibitor oprozomib synergizes with modulators of the unfolded protein response to suppress hepatocellular carcinoma

    PubMed Central

    Vandewynckel, Yves-Paul; Coucke, Céline; Laukens, Debby; Devisscher, Lindsey; Paridaens, Annelies; Bogaerts, Eliene; Vandierendonck, Astrid; Raevens, Sarah; Verhelst, Xavier; Van Steenkiste, Christophe; Libbrecht, Louis; Geerts, Anja; Van Vlierberghe, Hans

    2016-01-01

    Hepatocellular carcinoma (HCC) responds poorly to conventional systemic therapies. The first-in-class proteasome inhibitor bortezomib has been approved in clinical use for hematologic malignancies and has shown modest activity in solid tumors, including HCC. However, a considerable proportion of patients fail to respond and experience important adverse events. Recently, the next-generation orally bioavailable irreversible proteasome inhibitor oprozomib was developed. Here, we assessed the efficacy of oprozomib and its effects on the unfolded protein response (UPR), a signaling cascade activated through the ATF6, PERK and IRE1 pathways by accumulation of unfolded proteins in the endoplasmic reticulum, in HCC. The effects of oprozomib and the role of the UPR were evaluated in HCC cell lines and in diethylnitrosamine-induced and xenograft mouse models for HCC. Oprozomib dose-dependently reduced the viability and proliferation of human HCC cells. Unexpectedly, oprozomib-treated cells displayed diminished cytoprotective ATF6-mediated signal transduction as well as unaltered PERK and IRE1 signaling. However, oprozomib increased pro-apoptotic UPR-mediated protein levels by prolonging their half-life, implying that the proteasome acts as a negative UPR regulator. Supplementary boosting of UPR activity synergistically improved the sensitivity to oprozomib via the PERK pathway. Oral oprozomib displayed significant antitumor effects in the orthotopic and xenograft models for HCC, and importantly, combining oprozomib with different UPR activators enhanced the antitumor efficacy by stimulating UPR-induced apoptosis without cumulative toxicity. In conclusion, next-generation proteasome inhibition by oprozomib results in dysregulated UPR activation in HCC. This finding can be exploited to enhance the antitumor efficacy by combining oprozomib with clinically applicable UPR activators. PMID:27167000

  16. Making Earth Science Relevant in the K-8 Classroom. The Development of an Instructional Soils Module for Pre-Service Elementary Teachers Using the Next Generation Science Standards

    NASA Astrophysics Data System (ADS)

    Baldwin, K. A.; Hauge, R.; Dechaine, J. M.; Varrella, G.; Egger, A. E.

    2013-12-01

    The development and adoption of the Next Generation Science Standards (NGSS) raises a challenge in teacher preparation: few current teacher preparation programs prepare students to teach science the way it is presented in the NGSS, which emphasize systems thinking, interdisciplinary science, and deep engagement in the scientific process. In addition, the NGSS include more geoscience concepts and methods than previous standards, yet this is a topic area in which most college students are traditionally underprepared. Although nationwide, programmatic reform is needed, there are a few targets where relatively small, course-level changes can have a large effect. One of these targets is the 'science methods' course for pre-service elementary teachers, a requirement in virtually all teacher preparation programs. Since many elementary schools, both locally and across the country, have adopted a kit based science curriculum, examining kits is often a part of a science methods course. Unfortunately, solely relying on a kit based curriculum may leave gaps in science content curriculum as one prepares teachers to meet the NGSS. Moreover, kits developed at the national level often fall short in connecting geoscientific content to the locally relevant societal issues that engage students. This highlights the need to train pre-service elementary teachers to supplement kit curriculum with inquiry based geoscience investigations that consider relevant societal issues, promote systems thinking and incorporate connections between earth, life, and physical systems. We are developing a module that teaches geoscience concepts in the context of locally relevant societal issues while modeling effective pedagogy for pre-service elementary teachers. Specifically, we focus on soils, an interdisciplinary topic relevant to multiple geoscience-related societal grand challenges (e.g., water, food) that is difficult to engage students in. Module development is funded through InTeGrate, NSF

  17. Exploiting in situ antigen generation and immune modulation to enhance chemotherapy response in advanced melanoma: A combination nanomedicine approach.

    PubMed

    Lu, Yao; Wang, Yuhua; Miao, Lei; Haynes, Matthew; Xiang, Guangya; Huang, Leaf

    2016-08-28

    Therapeutic anticancer vaccine development must address a number of barriers to achieve successful tumor specific killing, including effective antigen presentation and antigen-specific T-cell activation to mediate cytotoxic cellular effects, inhibition of an immune-suppressive tumor microenvironment in order to facilitate and enhance CTL activity, and induction of memory T-cells to prolong tumor rejection. While traditional as well as modern vaccines rely upon delivery of both antigen and adjuvant, a variety of clinically relevant cancers lack ideal immunogenic antigens. Building upon recent efforts, we instead chose to exploit chemotherapy-induced apoptosis to allow for in situ antigen generation in a combination, nanomedicine-based approach. Specifically, lipid-coated cisplatin nanoparticles (LPC) and CpG-encapsulated liposomes (CpG-Lipo) were prepared for the temporally-controlled and multifaceted treatment of an advanced in vivo model of melanoma. Such combination therapy established strong synergistic effects, both in apoptotic extent and subsequent abrogation of tumor growth, which were due largely to both an enhanced cytotoxic T-cell recruitment and a reduction of immune-suppressive mediators in the microenvironments of both spleens and tumor. These results underlie a prolonged host lifespan in the combination approach (45 days) as compared with control (25 days, p < 0.02), providing promise toward a personalized approach to nanomedicine by establishing effect synergy in host-specific immunotherapy following chemotherapy.

  18. Exploiting in situ antigen generation and immune modulation to enhance chemotherapy response in advanced melanoma: A combination nanomedicine approach.

    PubMed

    Lu, Yao; Wang, Yuhua; Miao, Lei; Haynes, Matthew; Xiang, Guangya; Huang, Leaf

    2016-08-28

    Therapeutic anticancer vaccine development must address a number of barriers to achieve successful tumor specific killing, including effective antigen presentation and antigen-specific T-cell activation to mediate cytotoxic cellular effects, inhibition of an immune-suppressive tumor microenvironment in order to facilitate and enhance CTL activity, and induction of memory T-cells to prolong tumor rejection. While traditional as well as modern vaccines rely upon delivery of both antigen and adjuvant, a variety of clinically relevant cancers lack ideal immunogenic antigens. Building upon recent efforts, we instead chose to exploit chemotherapy-induced apoptosis to allow for in situ antigen generation in a combination, nanomedicine-based approach. Specifically, lipid-coated cisplatin nanoparticles (LPC) and CpG-encapsulated liposomes (CpG-Lipo) were prepared for the temporally-controlled and multifaceted treatment of an advanced in vivo model of melanoma. Such combination therapy established strong synergistic effects, both in apoptotic extent and subsequent abrogation of tumor growth, which were due largely to both an enhanced cytotoxic T-cell recruitment and a reduction of immune-suppressive mediators in the microenvironments of both spleens and tumor. These results underlie a prolonged host lifespan in the combination approach (45 days) as compared with control (25 days, p < 0.02), providing promise toward a personalized approach to nanomedicine by establishing effect synergy in host-specific immunotherapy following chemotherapy. PMID:27235608

  19. Modulating lignin in plants

    SciTech Connect

    Apuya, Nestor; Bobzin, Steven Craig; Okamuro, Jack; Zhang, Ke

    2013-01-29

    Materials and methods for modulating (e.g., increasing or decreasing) lignin content in plants are disclosed. For example, nucleic acids encoding lignin-modulating polypeptides are disclosed as well as methods for using such nucleic acids to generate transgenic plants having a modulated lignin content.

  20. Novel step-tunable wavelength-swept optical system based on a SSB modulator driven by a RF generator for fiber sensing networks

    NASA Astrophysics Data System (ADS)

    Yang, Tianxin; Qiu, Changren; Wang, Changle; Wang, Zhaoying; Ge, Chunfeng; Sang, Mei

    2012-03-01

    High resolution wavelength-tunable lasers are essential to sensing applications. For sensing applications, high resolution is needed to improve the spatial resolution and/or measurement accuracy, and fast tuning (sweeping) is required to enhance the measurement speed for dynamic sensing. However the demand of high resolution conflicts with the requirement of fast continuous wavelength tuning. The solution to this issue is tuning the wavelength of the output in a quasi-continuous way in which the length of each step is dependent on the frequency of a RF generator which is used to drive a single-sideband (SSB) modulator in the wavelength-swept optical system. In this paper, a principle of the step-tunable wavelength-swept optical system is proposed and demonstrated. The two optical features of narrow bandwidth and fairly high optical output power make the system unique for improving the accuracy of the measurement of the center-wavelength of a fiber Bragg grating (FBG) sensor. In addition, changing the tuning-step by adjusting the frequency of a RF generator electrically is user-friendly compared to the conventional wavelength swept systems by tuning optical elements mechanically.

  1. Modulating the interaction between gold and TiO2 nanowires for enhanced solar driven photoelectrocatalytic hydrogen generation.

    PubMed

    Sudhagar, P; Song, Taeseup; Devadoss, Anitha; Lee, Jung Woo; Haro, Marta; Terashima, Chiaki; Lysak, Volodymyr V; Bisquert, Juan; Fujishima, Akira; Gimenez, Sixto; Paik, Ungyu

    2015-07-15

    The interaction strength of Au nanoparticles with pristine and nitrogen doped TiO2 nanowire surfaces was analysed using density functional theory and their significance in enhancing the solar driven photoelectrocatalytic properties was elucidated. In this article, we prepared 4-dimethylaminopyridine capped Au nanoparticle decorated TiO2 nanowire systems. The density functional theory calculations show {101} facets of TiO2 as the preferred phase for dimethylaminopyridine-Au nanoparticles anchoring with a binding energy of -8.282 kcal mol(-1). Besides, the interaction strength of Au nanoparticles was enhanced nearly four-fold (-35.559 kcal mol(-1)) at {101} facets via nitrogen doping, which indeed amplified the Au nanoparticle density on nitrided TiO2. The Au coated nitrogen doped TiO2 (N-TiO2-Au) hybrid electrodes show higher absorbance owing to the light scattering effect of Au nanoparticles. In addition, N-TiO2-Au hybrid electrodes block the charge leakage from the electrode to the electrolyte and thus reduce the charge recombination at the electrode/electrolyte interface. Despite the beneficial band narrowing effect of nitrogen in TiO2 on the electrochemical and visible light activity in N-TiO2-Au hybrid electrodes, it results in low photocurrent generation at higher Au NP loading (3.4 × 10(-7) M) due to light blocking the N-TiO2 surface. Strikingly, even with a ten-fold lower Au NP loading (0.34 × 10(-7) M), the synergistic effects of nitrogen doping and Au NPs on the N-TiO2-Au hybrid system yield high photocurrent compared to TiO2 and TiO2-Au electrodes. As a result, the N-TiO2-Au electrode produces nearly 270 μmol h(-1) cm(-2) hydrogen, which is nearly two-fold higher than the pristine TiO2 counterpart. The implications of these findings for the design of efficient hybrid photoelectrocatalytic electrodes are discussed.

  2. Firefighting Module

    NASA Astrophysics Data System (ADS)

    1981-01-01

    Aviation Power Supply's mobile firefighting module called Firefly II is mounted on a trailer pulled by a pickup truck. Trailer unit has two three- inch water cannons, and the pickup carries a six inch cannon. Completely self contained, module pumps 3,000 gallons of water a minute from hydrants or open bodies of water. Stream can go as far as 400 feet or can be employed in a high-loft mode to reach the tops of tall refinery towers. Compact Firefly II weighs only 2,500 pounds when fully fueled. Key component is a specially designed two stage pump. Power for the pump is generated by a gas turbine engine. Module also includes an electronic/pump controller, multiple hose connections, up to 1,500 feet of hose and fuel for four hours operation. Firefly trailer can be backed onto specially-built large fireboat.

  3. Firefighting Module

    NASA Astrophysics Data System (ADS)

    1980-01-01

    Aviation Power Supply's mobile firefighting module called Firefly II is mounted on a trailer pulled by a pickup truck. Trailer unit has two three- inch water cannons, and the pickup carries a six inch cannon. Completely self contained, module pumps 3,000 gallons of water a minute from hydrants or open bodies of water. Stream can go as far as 400 feet or can be employed in a high-loft mode to reach the tops of tall refinery towers. Compact Firefly II weighs only 2,500 pounds when fully fueled. Key component is a specially designed two stage pump. Power for the pump is generated by a gas turbine engine. Module also includes an electronic/pump controller, multiple hose connections, up to 1,500 feet of hose and fuel for four hours operation. Firefly trailer can be backed onto specially-built large fireboat.

  4. The divergent eukaryote Trichomonas vaginalis has an m7G cap methyltransferase capable of a single N2 methylation.

    PubMed

    Simoes-Barbosa, Augusto; Louly, Camila; Franco, Octávio L; Rubio, Mary A; Alfonzo, Juan D; Johnson, Patricia J

    2008-12-01

    Eukaryotic RNAs typically contain 5' cap structures that have been primarily studied in yeast and metazoa. The only known RNA cap structure in unicellular protists is the unusual Cap4 on Trypanosoma brucei mRNAs. We have found that T. vaginalis mRNAs are protected by a 5' cap structure, however, contrary to that typical for eukaryotes, T. vaginalis spliceosomal snRNAs lack a cap and may contain 5' monophophates. The distinctive 2,2,7-trimethylguanosine (TMG) cap structure usually found on snRNAs and snoRNAs is produced by hypermethylation of an m(7)G cap catalyzed by the enzyme trimethylguanosine synthase (Tgs). Here, we biochemically characterize the single T. vaginalis Tgs (TvTgs) encoded in its genome and demonstrate that TvTgs exhibits substrate specificity and amino acid requirements typical of an RNA cap-specific, m(7)G-dependent N2 methyltransferase. However, recombinant TvTgs is capable of catalysing only a single round of N2 methylation forming a 2,7-dimethylguanosine cap (DMG) as observed previously for Giardia lamblia. In contrast, recombinant Entamoeba histolytica and Trypanosoma brucei Tgs are capable of catalysing the formation of a TMG cap. These data suggest the presence of RNAs with a distinctive 5' DMG cap in Trichomonas and Giardia lineages that are absent in other protist lineages.

  5. The M=7.9 Alaska Earthquake of 3 November 2002: felt reports and unusual effects across western Canada

    NASA Astrophysics Data System (ADS)

    Bird, A. L.; Cassidy, J. F.; Rogers, G. C.; Mulder, T. L.

    2003-04-01

    The 3~November 2002, M=7.9 Alaska earthquake was one of the largest earthquakes recorded in North America during the past 100 years. This earthquake was located 330~km west of the Yukon-Alaska border; surface rupture and aftershocks extended to within about 100~km of the border. More than 250 ``felt'' reports were submitted to the Geological Survey of Canda website (http://www.pgc.nrcan.gc.ca) within a few days of the earthquake. We summarize those reports from across western Canada. Accounts include typical high-frequency shaking effects to distances of approximately 1500~km, as well as numerous long-period effects to distances of nearly 3500~km: humans experiencing nausea, swaying high-rise buildings, telephone poles and chandeliers, seiches in lakes, inlets and swimming pools, instances of dirty well-water.

  6. Acoustic Emission Precursors of M6.0 2004 Parkfield and M7.0 1989Loma Prieta Earthquakes

    SciTech Connect

    Korneev, Valeri

    2005-02-01

    Two recent strike-slip earthquakes on the San Andreas Fault(SAF) in California, the M6.0 2004 Parkfield and M7.0 1989 Loma Prietaevents, revealed peaks in the acoustic emission (AE) activity in thesurrounding crust several months prior to the main events. Earthquakesdirectly within the SAF zone were intentionally excluded from theanalysis. The observed increase in AE is assumed to be a signature of theincreasing stress level in the surrounding crust, while the peak andsubsequent decrease in AE starting several months prior to the mainevents is attributed to damage-induced softening processes as discussedherein. Further, distinctive zones of low seismic activity surroundingthe epicentral regions in the pre-event time period are present for thetwo studied events. Both AE increases in the crust surrounding apotential future event and the development of a low-seismicity epicentralzone can be regarded as promising precursory information that could helpsignal the arrival of large earthquakes.

  7. Coseismic and postseismic vertical movements associated with the 1940 M7.1 Imperial Valley, California, earthquake

    NASA Technical Reports Server (NTRS)

    Reilinger, R.

    1984-01-01

    Leveling surveys conducted along two routes that cross the Imperial fault in southern California indicate spatially coherent elevation changes attributable to coseismic and postseismic effects of the 1940, M7.1 Imperial Valley earthquake. The 1931-1941 elevation changes are consistent with theoretical models of vertical deformation of an elastic half space for a finite length strike-slip fault, using fault parameters that are consistent with the observed surface offsets following the 1940 earthquake. The elevation changes suggest an earthquake scenario consisting of a large coeismic slip in the southern half of the fault which transferred stress to the northern part as well as to the Brawley fault to the northeast.

  8. Hybrid organic/inorganic band-edge modulation of p-Si(111) photoelectrodes: effects of R, metal oxide, and Pt on H2 generation.

    PubMed

    Seo, Junhyeok; Kim, Hark Jin; Pekarek, Ryan T; Rose, Michael J

    2015-03-11

    The efficient generation of dihydrogen on molecularly modified p-Si(111) has remained a challenge due to the low barrier heights observed on such surfaces. The band-edge and barrier height challenge is a primary obstruction to progress in the area of integration of molecular H2 electrocatalysts with silicon photoelectrodes. In this work, we demonstrate that an optimal combination of organic passivating agent and inorganic metal oxide leads to H2 evolution at photovoltages positive of RHE. Modulation of the passivating R group [CH3 → Ph → Naph → Anth → Ph(OMe)2] improves both the band-edge position and ΔV (Vonset - VJmax). Subsequent atomic layer deposition (ALD) of Al2O3 or TiO2 along with ALD-Pt deposition results in to our knowledge the first example of a positive H2 operating potential on molecularly modified Si(111). Mott-Schottky analyses reveal that the flat-band potential of the stable Ph(OMe)2 surface approaches that of the native (but unstable) hydride-terminated surface. The series resistance is diminished by the methoxy functional groups on the phenyl unit, due to its chemical and electronic connectivity with the TiO2 layer. Overall, judicious choice of the R group in conjunction with TiO2|Pt effects H2 generation on p-Si(111) photoelectrodes (Voc = 207 ± 5.2 mV; Jsc = -21.7 mA/cm(2); ff = 0.22; ηH2 = 0.99%). These results provide a viable hybrid strategy toward the operation of catalysts on molecularly modified p-Si(111).

  9. Alternative Splicing Generates a Diacylglycerol Kinase α Transcript That Acts as a Dominant-Negative Modulator of Superoxide Production in Localized Aggressive Periodontitis

    PubMed Central

    Batista, Eraldo L.; Kantarci, Alpdogan I.; Hasturk, Hatice; Van Dyke, Thomas E.

    2015-01-01

    Background Diacylglycerol (DAG), levels of which are tightly regulated by diacylglycerol kinases (DGKs), is a lipid mediator linked to key biologic functions. Members of the DGK family undergo alternative splicing, generating the protein diversity necessary to control different intracellular DAG pools. DGKα function is altered in polymorphonuclear neutrophils (PMNs) of patients with localized aggressive periodontitis (LAgP), suggesting a genetic basis. Here, the authors assess DGKα spliced transcripts in human LAgP neutrophils. Methods In an expression library of a patient with LAgP, PMNs were screened for different DGKα transcripts. Real-time polymerase chain reaction and in vitro expression assays were performed to assess the fate of different transcripts on protein translocation and superoxide production in human leukemia cells (HL-60) and COS-7 cells. Results A DGKα transcript that lacks exon 10 (DGKαΔ10) and generates a premature stop codon and a truncated protein was identified as being upregulated in LAgP neutrophils. In vitro assays revealed that DGKαΔ10 translocation occurred even in the absence of important regulatory motifs. Transfection of HL-60 neutrophil-like cells with the DGKαΔ10 spliced variant induced an increase in the stimulated production of su-peroxide anion replicating the phenotype of LAgP PMNs. Conclusion DGKαΔ10 can act as a dominant-negative transcript that can modulate superoxide production and provides an example of genetic regulation of the inflammatory response that may be relevant to human inflammatory diseases such as LAgP. J Periodontol 2014;85:934-943. PMID:24171497

  10. Software-only IR image generation and reticle simulation for the HWIL testing of a single detector frequency modulated reticle seeker

    NASA Astrophysics Data System (ADS)

    Delport, Jan Peet; le Roux, Francois P. J.; du Plooy, Matthys J. U.; Theron, Hendrik J.; Annamalai, Leeandran

    2004-08-01

    Hardware-in-the-Loop (HWIL) testing of seeker systems usually requires a 5-axis flight motion simulator (FMS) coupled to expensive hardware for infrared (IR) scene generation and projection. Similar tests can be conducted by using a 3-axis flight motion simulator, bypassing the seeker optics and injecting a synthetically calculated detector signal directly into the seeker. The constantly increasing speed and memory bandwidth of high-end personal computers make them attractive software rendering platforms. A software OpenGL pipeline provides flexibility in terms of access to the rendered output, colour channel dynamic range and lighting equations. This paper describes how a system was constructed using personal computer hardware to perform closed tracking loop HWIL testing of a single detector frequency modulated reticle seeker. The main parts of the system that are described include: * The software-only implementation of OpenGL used to render the IR image with floating point accuracy directly to system memory. * The software used to inject the detector signal and extract the seeker look position. * The architecture used to control the flight motion simulator.

  11. A Hox Transcription Factor Collective Binds a Highly Conserved Distal-less cis-Regulatory Module to Generate Robust Transcriptional Outcomes

    PubMed Central

    Uhl, Juli D.; Zandvakili, Arya; Gebelein, Brian

    2016-01-01

    cis-regulatory modules (CRMs) generate precise expression patterns by integrating numerous transcription factors (TFs). Surprisingly, CRMs that control essential gene patterns can differ greatly in conservation, suggesting distinct constraints on TF binding sites. Here, we show that a highly conserved Distal-less regulatory element (DCRE) that controls gene expression in leg precursor cells recruits multiple Hox, Extradenticle (Exd) and Homothorax (Hth) complexes to mediate dual outputs: thoracic activation and abdominal repression. Using reporter assays, we found that abdominal repression is particularly robust, as neither individual binding site mutations nor a DNA binding deficient Hth protein abolished cooperative DNA binding and in vivo repression. Moreover, a re-engineered DCRE containing a distinct configuration of Hox, Exd, and Hth sites also mediated abdominal Hox repression. However, the re-engineered DCRE failed to perform additional segment-specific functions such as thoracic activation. These findings are consistent with two emerging concepts in gene regulation: First, the abdominal Hox/Exd/Hth factors utilize protein-protein and protein-DNA interactions to form repression complexes on flexible combinations of sites, consistent with the TF collective model of CRM organization. Second, the conserved DCRE mediates multiple cell-type specific outputs, consistent with recent findings that pleiotropic CRMs are associated with conserved TF binding and added evolutionary constraints. PMID:27058369

  12. Modulation of TNFalpha, a determinant of acute toxicity associated with systemic delivery of first-generation and helper-dependent adenoviral vectors.

    PubMed

    Mane, V P; Toietta, G; McCormack, W M; Conde, I; Clarke, C; Palmer, D; Finegold, M J; Pastore, L; Ng, P; Lopez, J; Lee, B

    2006-09-01

    Understanding the determinants of the host innate immune response to systemic administration of adenoviral (Ad) vectors is critical for clinical gene therapy. Acute toxicity occurs within minutes to hours after vector administration and is characterized by activation of innate immune responses. Our data indicate that in mice, indicators of vector toxicity include elevations of cytokine levels, liver transaminase levels and thrombocytopenia. To discern potential targets for blunting this host response, we evaluated genetic factors in the host response to systemically administered first-generation Ad vectors (FGV) and helper-dependent Ad vectors (HDV) containing beta-galactosidase expression cassettes. A preliminary screen for modulation of vector-induced thrombocytopenia revealed no role for interferon-gamma, mast cells or perforin. However, vector-induced thrombocytopenia and interleukin 6 (IL-6) expression are less evident in tumor necrosis factor alpha (TNFalpha)-deficient mice. Moreover, we also demonstrated that TNFalpha blockade via antibody or huTNFR:Fc pretreatment attenuates both thrombocytopenia (>40% increase in platelet count) and IL-6 expression (>80% reduction) without affecting interleukin 12 , liver enzymes, hematological indices or vector transduction in a murine model. Our data indicate that the use of HDV, in combination with clinically approved TNFalpha immunomodulation, may represent an approach for improving the therapeutic index of Ad gene therapy for human clinical trials. PMID:16708078

  13. Energy metabolism disorders in rare and common diseases. Toward bioenergetic modulation therapy and the training of a new generation of European scientists.

    PubMed

    Rossignol, Rodrigue

    2015-06-01

    Energy metabolism alterations are found in a large number of rare and common diseases of genetic or environmental origin. The number of patients that could benefit from bioenergetic modulation therapy (BIOMET) is therefore very important and includes individuals with pathologies as diverse as mitochondrial diseases, acute coronary syndrome, chronic kidney disease, asthma or even cancer. Although, the alteration of energy metabolism is disease specific and sometimes patient specific, the strategies for BIOMET could be common and target a series of bioenergetic regulatory mechanisms discussed in this article. An excellent training of scientists in the field of energy metabolism, related human diseases and drug discovery is also crucial to form a young generation of MDs, PHDs and Pharma or CRO-group leaders who will discover novel personalized bioenergetic medicines, through pharmacology, genetics, nutrition or adapted exercise training. The Mitochondrial European Educational Training (MEET) consortium was created to pursue this goal, and we dedicated here a special issue of Organelle in Focus (OiF) to highlight their objectives. A total of 10 OiFs articles constitute this Directed Issue on Mitochondrial Medicine. As part of this editorial article, we asked timely questions to the PR. Jan W. Smeitink, professor of Mitochondrial Medicine and CEO of Khondrion, a mitochondrial medicine company. He shared with us his objectives and strategies for the study of mitochondrial diseases and the identification of future treatments. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies. PMID:25595463

  14. A Hox Transcription Factor Collective Binds a Highly Conserved Distal-less cis-Regulatory Module to Generate Robust Transcriptional Outcomes.

    PubMed

    Uhl, Juli D; Zandvakili, Arya; Gebelein, Brian

    2016-04-01

    cis-regulatory modules (CRMs) generate precise expression patterns by integrating numerous transcription factors (TFs). Surprisingly, CRMs that control essential gene patterns can differ greatly in conservation, suggesting distinct constraints on TF binding sites. Here, we show that a highly conserved Distal-less regulatory element (DCRE) that controls gene expression in leg precursor cells recruits multiple Hox, Extradenticle (Exd) and Homothorax (Hth) complexes to mediate dual outputs: thoracic activation and abdominal repression. Using reporter assays, we found that abdominal repression is particularly robust, as neither individual binding site mutations nor a DNA binding deficient Hth protein abolished cooperative DNA binding and in vivo repression. Moreover, a re-engineered DCRE containing a distinct configuration of Hox, Exd, and Hth sites also mediated abdominal Hox repression. However, the re-engineered DCRE failed to perform additional segment-specific functions such as thoracic activation. These findings are consistent with two emerging concepts in gene regulation: First, the abdominal Hox/Exd/Hth factors utilize protein-protein and protein-DNA interactions to form repression complexes on flexible combinations of sites, consistent with the TF collective model of CRM organization. Second, the conserved DCRE mediates multiple cell-type specific outputs, consistent with recent findings that pleiotropic CRMs are associated with conserved TF binding and added evolutionary constraints. PMID:27058369

  15. A Hox Transcription Factor Collective Binds a Highly Conserved Distal-less cis-Regulatory Module to Generate Robust Transcriptional Outcomes.

    PubMed

    Uhl, Juli D; Zandvakili, Arya; Gebelein, Brian

    2016-04-01

    cis-regulatory modules (CRMs) generate precise expression patterns by integrating numerous transcription factors (TFs). Surprisingly, CRMs that control essential gene patterns can differ greatly in conservation, suggesting distinct constraints on TF binding sites. Here, we show that a highly conserved Distal-less regulatory element (DCRE) that controls gene expression in leg precursor cells recruits multiple Hox, Extradenticle (Exd) and Homothorax (Hth) complexes to mediate dual outputs: thoracic activation and abdominal repression. Using reporter assays, we found that abdominal repression is particularly robust, as neither individual binding site mutations nor a DNA binding deficient Hth protein abolished cooperative DNA binding and in vivo repression. Moreover, a re-engineered DCRE containing a distinct configuration of Hox, Exd, and Hth sites also mediated abdominal Hox repression. However, the re-engineered DCRE failed to perform additional segment-specific functions such as thoracic activation. These findings are consistent with two emerging concepts in gene regulation: First, the abdominal Hox/Exd/Hth factors utilize protein-protein and protein-DNA interactions to form repression complexes on flexible combinations of sites, consistent with the TF collective model of CRM organization. Second, the conserved DCRE mediates multiple cell-type specific outputs, consistent with recent findings that pleiotropic CRMs are associated with conserved TF binding and added evolutionary constraints.

  16. Effects of superoxide anion generators and thiol modulators on nitrergic transmission and relaxation to exogenous nitric oxide in the sheep urethra

    PubMed Central

    Garcia-Pascual, A; Labadia, A; Costa, G; Triguero, D

    2000-01-01

    The effects of superoxide anion generators, the nitric oxide (NO) scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoine-1-oxyl 3-oxide (carboxy-PTIO), the specific guanylate cyclase inhibitor 1H-[1,2,4]-oxadiazole-[4,3-a]-quinoxalin-1-one (ODQ), and thiol modulating agents were investigated on relaxations induced by nitrergic stimulation and exogenous NO addition in the sheep urethra. Methylene blue (MB, 10 μM), pyrogallol (0.1 mM) and xanthine (X, 0.1 mM)/xanthine oxidase (XO, 0.1 u ml−1) inhibited NO-mediated relaxations, without affecting those induced by nitrergic stimulation. This resistance was not diminished following inhibition of endogenous Cu/Zn superoxide dismutase (Cu/Zn SOD) with diethyldithiocarbamic acid (DETCA, 3 mM), which almost abolished tissue SOD activity. Carboxy-PTIO (0.1–0.5 mM) inhibited NO-mediated relaxations but had no effect on responses to nitrergic stimulation, which were not changed by treatment with ascorbate oxidase (2 u ml−1). Relaxations to NO were reduced, but not abolished, by ODQ (10 μM), while nitrergic responses were completely blocked. The thiol modulators, ethacrynic acid (0.1 mM), diamide (1.5 mM), or 5,5′-dithio-bis (2-nitrobenzoic acid) (DTNB, 0.5 mM), and subsequent treatment with dithiothreitol (DTT, 2 mM) had no effect on responses to nitrergic stimulation or NO. In contrast, N-ethylmaleimide (NEM, 0.2 mM) markedly inhibited both relaxations. L-cysteine (L-cys, 0.1 mM) had no effect on responses to NO, while it inhibited those to nitrergic stimulation, in a Cu/Zn SOD-independent manner. Our results do not support the view that the urethral nitrergic transmitter is free NO, and the possibility that another compound is acting as mediator still remains open. PMID:10694202

  17. Post-Seismic Fault Healing on the Rupture Zone of the 1999 M7.1 Hector Mine, California Earthquake

    NASA Astrophysics Data System (ADS)

    Li, Y.; Vidale, J. E.; Day, S. M.; Oglesby, D. D.; Cochran, E.; Gross, K.; Burdette, T.; Alvarez, M.

    2002-12-01

    We probed the rupture zone of the October 1999 M7.1 Hector Mine earthquake using repeated near-surface explosions in October, 2000 and November, 2001. Three dense linear seismic arrays were deployed across the north and south Lavic Lake faults (LLF) that broke to the surface in the mainshock, and across the Bullion fault (BF) that experienced minor slip in that event. Two explosions each year were detonated in the rupture zone on the middle and south LLF, respectively. We found that P and S velocities of fault-zone rocks increased by ~0.7 to 1.4% and ~0.5 to 1.0% between 2000 and 2001, respectively. In contrast, the velocities for P and S waves in surrounding rocks increased much less. This trend indicates the Hector Mine rupture zone has been healing by strengthening after the mainshock, which we attribute to the closure of cracks that opened during the 1999 earthquake. The 'crack dilatancy' mechanisms are most likely to operate for fault healing at shallow depth although the healing may be controlled by a combination of mechanical and chemical processes on the fault during the earthquake cycle. The observed fault-zone strength recovery is consistent with an apparent crack density decrease of 1.5% within the rupture zone. The ratio of travel time decrease for P to S waves was 0.72, consistent with partially fluid-filled cracks near the fault zone were. We also find variability in healing rates between the fault segments. The velocity increase with time varies from one fault segment to another at the Hector Mine rupture zone. We see greater changes on the LLF than on the BF, and the greatest change is on the middle LLF at shallow depth. We speculate that greater damage was inflicted, and thus greater healing is observed, in regions with larger slip in the mainshock. This post-seismic restrengthening of the Hector Mine rupture zone is similar to that observed on the Johnson Valley fault which ruptured in the 1992 M7.4 Landers earthquake (Li and Vidale, GRL, 2001

  18. Rupture directivity and local site effects: the M7.3 Honduras earthquake of May 23, 2009

    NASA Astrophysics Data System (ADS)

    Shulman, D.; Mooney, W. D.

    2009-12-01

    On May 28, 2009, at 2:24 AM local time, a M 7.3 earthquake struck off the coast of Honduras on the Motagua-Swan Fault System (MSFS), part of the boundary between the North America and Caribbean plates. This plate boundary has an average slip rate of 20 mm/year. This left-lateral earthquake had an average slip of 1.5 m on a 100-km-long near-vertical fault plane (Hayes and Ji, 2009). The hypocenter depth is estimated at 10 km. The main shock caused 130 structures, including homes and office buildings, to collapse or suffer significant damage in northern Honduras. Seven deaths were reported. Due to a lack of recordings in the area, the available documentation of the local effects of this earthquake are the USGS "Did you feel it?" responses and the data collected during our field seismic intensity investigation. We conducted a field investigation in Honduras between May 30 and June 6, 2009, focused on areas with local reports of damage, including the cities of La Ceiba, El Progresso, San Pedro Sula, Puerto Cortes in northern Honduras and the island of Roatan in the Caribbean Sea. The damage ascertained at these five sites shows that the severity of damage did not decrease with distance from the epicenter as predicted by standard attenuation relations. Instead, a concentration of damage was observed in El Progresso, approximately 75 km directly south from the SW end of the rupture and 160 km from the epicenter. The island of Roatan, just 30 km from the epicenter, was graded as VI on the Modified Mercalli Intensity scale while, El Progresso was graded as VIII (one unit higher than “Did you feel it?”). These intensity anomalies can be explained by two factors: (1) SW-directed rupture propagation and proximity to a localized 3.0m slip pulse (asperity) that occurred near the SW end of the fault (Hayes and Ji, 2009) that focused energy toward the city of El Progress on the mainland and; (2) local site effects, particularly the Precambrian schists and gneisses on the

  19. The 1992 M=7 Cape Mendocino, California, earthquake: Coseismic deformation at the south end of the Cascadia megathrust

    USGS Publications Warehouse

    Murray, M.H.; Marshall, G.A.; Lisowski, M.; Stein, R.S.

    1996-01-01

    We invert geodetic measurements of coseismic surface displacements to determine a dislocation model for the April 25, 1992, M=7 Cape Mendocino, California, earthquake. The orientation of the model slip vector, which nearly parallels North America-Juan de Fuca relative plate convergence, and the location and orientation of the model fault relative to the offshore Cascadia megathrust, suggest that the 1992 Cape Mendocino earthquake is the first well-recorded event to relieve strain associated with the Cascadia subduction zone. We use data from three geodetic techniques: (1) the horizontal and vertical displacements of 13 monuments surveyed with the Global Positioning System, corrected for observed horizontal interseismic strain accumulation, (2) 88 section-elevation differences between leveling monuments, and (3) the uplift of 12 coastal sites observed from the die-off of intertidal marine organisms. Maximum observed displacements are 0.4 m of horizontal movement and 1.5 m of uplift along the coast. We use Monte Carlo techniques to estimate an optimal uniform slip rectangular fault geometry and its uncertainties. The optimal model using all the data resolves 4.9 m of slip on a 14 by 15 km fault that dips 28?? SE. The fault extends from 1.5 to 8.7 km in depth and the main-shock hypocenter is close to the downdip projection of the fault. The shallowly dipping fault plane is consistent with the observed aftershock locations, and the estimated geodetic moment is 3.1??1019 N m, 70% of the seismic moment. Other models that exclude leveling data collected in 1935 and 1942 are more consistent with seismological estimates of the fault geometry. If the earthquake is characteristic for this segment, the estimated horizontal slip vector compared with plate convergence rates suggests a recurrence interval of 140 years, with a 95% confidence range of 100-670 years. The coseismic uplift occurred in a region that also has high Quaternary uplift rates determined from marine terrace

  20. Amplitude Modulator Chassis

    SciTech Connect

    Erbert, G

    2009-09-01

    The Amplitude Modulator Chassis (AMC) is the final component in the MOR system and connects directly to the PAM input through a 100-meter fiber. The 48 AMCs temporally shape the 48 outputs of the MOR using an arbitrary waveform generator coupled to an amplitude modulator. The amplitude modulation element is a two stage, Lithium Niobate waveguide device, where the intensity of the light passing through the device is a function of the electrical drive applied. The first stage of the modulator is connected to a programmable high performance Arbitrary Waveform Generator (AWG) consisting of 140 impulse generators space 250 ps apart. An arbitrary waveform is generated by independently varying the amplitude of each impulse generator and then summing the impulses together. In addition to the AWG a short pulse generator is also connected to the first stage of the modulator to provide a sub 100-ps pulse used for timing experiments. The second stage of the modulator is connect to a square pulse generator used to further attenuate any pre or post pulse light passing through the first stage of the modulator. The fast rise and fall time of the square pulse generator is also used to produce fast rise and fall times of the AWG by clipping the AWG pulse. For maximum extinction, a pulse bias voltage is applied to each stage of the modulator. A pulse voltage is applied as opposed to a DC voltage to prevent charge buildup on the modulator. Each bias voltage is adjustable to provide a minimum of 50-dB extinction. The AMC is controlled through ICCS to generate the desired temporal pulse shape. This process involves a closed-loop control algorithm, which compares the desired temporal waveform to the produced optical pulse, and iterates the programming of the AWG until the two waveforms agree within an allowable tolerance.

  1. Identification and role analysis of an intermediate produced by a polygenic mutant of Monascus pigments cluster in Monascus ruber M7.

    PubMed

    Liu, Jiao; Zhou, Youxiang; Yi, Tao; Zhao, Mingming; Xie, Nana; Lei, Ming; Liu, Qingpei; Shao, Yanchun; Chen, Fusheng

    2016-08-01

    Monascus pigments (Mps) are a group of azaphilonic secondary metabolites produced by Monascus spp. via a polyketide pathway. A mutant deleted an about 30 kb region of Mps gene cluster from Monascus ruber M7 was isolated previously, which produces a high amount of a light yellow pigment. The current study revealed that the mutant named ΔMpigJ-R lost proximate eight genes of the Mps gene cluster in M. ruber M7 through genetic analysis at DNA and RNA levels. The produced light yellow material was identified as a benzaldehyde derivative named as 6-(4-hydroxy-2-oxopentyl)-3-methyl-2, 4-dioxocyclohexane carb-aldehyde (M7PKS-1) by FT-IR, NMR, and MS. The sodium acetate-1-(13)C feeding experiment indicated that M7PKS-1 was a product produced from polyketide pathway. Finally, the feeding of M7PKS-1 helped to induce and regain Mps production of the mutants (ΔMpigA and ΔMpigE) which were previously unable to biosynthesize Mps and proved that M7PKS-1 was an initial intermediate of Mps. The results in this study provide a line of action to unveil Monascus pigments biosynthesis pathway. PMID:26946170

  2. Lateral spread hazard mapping of the northern Salt Lake Valley, Utah, for a M7.0 scenario earthquake

    USGS Publications Warehouse

    Olsen, M.J.; Bartlett, S.F.; Solomon, B.J.

    2007-01-01

    This paper describes the methodology used to develop a lateral spread-displacement hazard map for northern Salt Lake Valley, Utah, using a scenario M7.0 earthquake occurring on the Salt Lake City segment of the Wasatch fault. The mapping effort is supported by a substantial amount of geotechnical, geologic, and topographic data compiled for the Salt Lake Valley, Utah. ArcGIS?? routines created for the mapping project then input this information to perform site-specific lateral spread analyses using methods developed by Bartlett and Youd (1992) and Youd et al. (2002) at individual borehole locations. The distributions of predicted lateral spread displacements from the boreholes located spatially within a geologic unit were subsequently used to map the hazard for that particular unit. The mapped displacement zones consist of low hazard (0-0.1 m), moderate hazard (0.1-0.3 m), high hazard (0.3-1.0 m), and very high hazard (> 1.0 m). As expected, the produced map shows the highest hazard in the alluvial deposits at the center of the valley and in sandy deposits close to the fault. This mapping effort is currently being applied to the southern part of the Salt Lake Valley, Utah, and probabilistic maps are being developed for the entire valley. ?? 2007, Earthquake Engineering Research Institute.

  3. Rapid earthquake characterization using MEMS accelerometers and volunteer hosts following the M 7.2 Darfield, New Zealand, Earthquake

    USGS Publications Warehouse

    Lawrence, J. F.; Cochran, E.S.; Chung, A.; Kaiser, A.; Christensen, C. M.; Allen, R.; Baker, J.W.; Fry, B.; Heaton, T.; Kilb, Debi; Kohler, M.D.; Taufer, M.

    2014-01-01

    We test the feasibility of rapidly detecting and characterizing earthquakes with the Quake‐Catcher Network (QCN) that connects low‐cost microelectromechanical systems accelerometers to a network of volunteer‐owned, Internet‐connected computers. Following the 3 September 2010 M 7.2 Darfield, New Zealand, earthquake we installed over 180 QCN sensors in the Christchurch region to record the aftershock sequence. The sensors are monitored continuously by the host computer and send trigger reports to the central server. The central server correlates incoming triggers to detect when an earthquake has occurred. The location and magnitude are then rapidly estimated from a minimal set of received ground‐motion parameters. Full seismic time series are typically not retrieved for tens of minutes or even hours after an event. We benchmark the QCN real‐time detection performance against the GNS Science GeoNet earthquake catalog. Under normal network operations, QCN detects and characterizes earthquakes within 9.1 s of the earthquake rupture and determines the magnitude within 1 magnitude unit of that reported in the GNS catalog for 90% of the detections.

  4. Crystal structure of Bacillus subtilis TrmB, the tRNA (m7G46) methyltransferase.

    PubMed

    Zegers, Ingrid; Gigot, Daniel; van Vliet, Françoise; Tricot, Catherine; Aymerich, Stéphane; Bujnicki, Janusz M; Kosinski, Jan; Droogmans, Louis

    2006-01-01

    The structure of Bacillus subtilis TrmB (BsTrmB), the tRNA (m7G46) methyltransferase, was determined at a resolution of 2.1 A. This is the first structure of a member of the TrmB family to be determined by X-ray crystallography. It reveals a unique variant of the Rossmann-fold methyltransferase (RFM) structure, with the N-terminal helix folded on the opposite site of the catalytic domain. The architecture of the active site and a computational docking model of BsTrmB in complex with the methyl group donor S-adenosyl-L-methionine and the tRNA substrate provide an explanation for results from mutagenesis studies of an orthologous enzyme from Escherichia coli (EcTrmB). However, unlike EcTrmB, BsTrmB is shown here to be dimeric both in the crystal and in solution. The dimer interface has a hydrophobic core and buries a potassium ion and five water molecules. The evolutionary analysis of the putative interface residues in the TrmB family suggests that homodimerization may be a specific feature of TrmBs from Bacilli, which may represent an early stage of evolution to an obligatory dimer.

  5. Crystal structure of Bacillus subtilis TrmB, the tRNA (m7G46) methyltransferase

    PubMed Central

    Zegers, Ingrid; Gigot, Daniel; van Vliet, Françoise; Tricot, Catherine; Aymerich, Stéphane; Bujnicki, Janusz M.; Kosinski, Jan; Droogmans, Louis

    2006-01-01

    The structure of Bacillus subtilis TrmB (BsTrmB), the tRNA (m7G46) methyltransferase, was determined at a resolution of 2.1 Å. This is the first structure of a member of the TrmB family to be determined by X-ray crystallography. It reveals a unique variant of the Rossmann-fold methyltransferase (RFM) structure, with the N-terminal helix folded on the opposite site of the catalytic domain. The architecture of the active site and a computational docking model of BsTrmB in complex with the methyl group donor S-adenosyl-l-methionine and the tRNA substrate provide an explanation for results from mutagenesis studies of an orthologous enzyme from Escherichia coli (EcTrmB). However, unlike EcTrmB, BsTrmB is shown here to be dimeric both in the crystal and in solution. The dimer interface has a hydrophobic core and buries a potassium ion and five water molecules. The evolutionary analysis of the putative interface residues in the TrmB family suggests that homodimerization may be a specific feature of TrmBs from Bacilli, which may represent an early stage of evolution to an obligatory dimer. PMID:16600901

  6. Monacyclinones, New Angucyclinone Metabolites Isolated from Streptomyces sp. M7_15 Associated with the Puerto Rican Sponge Scopalina ruetzleri

    PubMed Central

    Vicente, Jan; Stewart, Allison K.; van Wagoner, Ryan M.; Elliott, Elizabeth; Bourdelais, Andrea J.; Wright, Jeffrey L. C.

    2015-01-01

    During an investigation of new actinomycete species from Caribbean sponges for novel bioactive natural products, frigocyclinone (1), dimethyldehydrorabelomycin (3) and six new angucyclinone derivatives were isolated from Streptomyces sp. strain M7_15 associated with the sponge Scopalina ruetzleri. Of these, monacyclinones A–B (4–5) contain the core ring structure of dehydrorabelomycin (2) with the aminodeoxysugar found in frigocyclinone (1). Monacyclinone C (6) is a hydroxylated variant of frigocyclinone (1) and monacyclinone D (7) is a Baeyer Villiger derivative of (6) which also exists as the open chain hydrolysis product monacyclinone E (8). Monacyclinone F (9) contains two unique epoxide rings attached to the angucyclinone moiety and an additional aminodeoxysugar attached through an angular oxygen bond. All structures were confirmed through spectral analyses. Activity against rhabdomycosarcoma cancer cells (SJCRH30) after 48 h of treatment was observed with frigocyclinone (1; EC50 = 5.2 µM), monacyclinone C (6; 160 µM), monacyclinone E (8; 270 µM), and monacyclinone F (9; 0.73 µM). The strongest bioactivity against rhabdomycosarcoma cancer cells and gram-positive bacteria was exhibited by compound 9, suggesting that the extra aminodeoxysugar subunit is important for biological activity. PMID:26230704

  7. Landslides and liquefaction triggered by the M 7.9 denali fault earthquake of 3 November 2002

    USGS Publications Warehouse

    Harp, E.L.; Jibson, R.W.; Kayen, R.E.; Keefer, D.K.; Sherrod, B.L.; Carver, G.A.; Collins, B.D.; Moss, R.E.S.; Sitar, N.

    2003-01-01

    The moment magnitude (M) 7.9 Denali Fault earthquake in Alaska of 3 November 2002 triggered an unusual pattern of landslides and liquefaction effects. The landslides were primarily rock falls and rock slides that ranged in volume from a few cubic meters to the 40 million-cubic-meter rock avalanche that covered much of the McGinnis Glacier. Landslides were concentrated in a narrow zone ???30 km wide that straddled the fault rupture zone over its entire 300 km length. Large rock avalanches all clustered at the western end of the rupture zone where acceleration levels are reported to have been the highest. Liquefaction effects, consisting of sand blows, lateral spreads, and settlement, were widespread within susceptible alluvial deposits extending from Fairbanks eastward several hundred kilometers. The liquefaction effects displayed a pattern of increasing concentration and severity from west to east and extended well beyond the zone of landslides, which is unusual. The contrasting patterns formed by the distributions of landslides and liquefaction effects initially seemed to be inconsistent; however, preliminary analyses of strong-motion records from the earthquake offer a possible explanation for the unusual ground-failure patterns that are related to three subevents that have been discerned from the earthquake records.

  8. Comparative structural analysis of HLA-A2 antigens distinguishable by cytotoxic T lymphocytes: variants M7 and DR1.

    PubMed

    Krangel, M S; Taketani, S; Biddison, W E; Strong, D M; Strominger, J L

    1982-11-23

    Comparative primary structural analyses have begun to elucidate polymorphic residues and segments of the class I antigens of the major histocompatibility complex, at least some of which presumably contribute to determinants important in immune recognition events. HLA-A2 structural variants have been described which are serologically indistinguishable from other HLA-A2 antigens, yet which can be recognized neither by HLA-A2 specific alloimmune nor by HLA-A2 restricted, virus immune cytotoxic T lymphocytes. This study utilizes double-label tryptic peptide comparisons in combination with both conventional and microsequence analyses to investigate the structure of two such variants, M7 and DR1. We find that these variants are identical with each other and differ from the predominant HLA-A2 heavy chain species by a glutamine to arginine substitution at residue 43, by an unidentified substitution in the tryptic peptide spanning residues 147-157, and by an as yet poorly defined alteration in glycosylation. Structural information from these and other variants should be useful in precisely defining functionally important determinants on the molecule. PMID:6983890

  9. Seismicity Precursors of the M6.0 2004 Parkfield and M7.0 1989Loma Prieta Earthquakes

    SciTech Connect

    Korneev, Valeri A.

    2006-03-09

    The M6.0 2004 Parkfield and M7.0 1989 Loma Prietastrike-slip earthquakes on the San Andreas Fault (SAF) were preceded byseismicity peaks occurring several months prior to the main events.Earthquakes directly within the SAF zone were intentionally excluded fromthe analysis because they manifest stress-release processes rather thanstress accumulation. The observed increase in seismicity is interpretedas a signature of the increasing stress level in the surrounding crust,whereas the peaks and the subsequent decrease in seismicity areattributed to damage-induced softening processes. Furthermore, in bothcases there is a distinctive zone of low seismic activity that surroundsthe epicentral region in the pre-event period. The increase of seismicityin the crust surrounding a potential future event and the development ofa low-seismicity epicentral zone can be regarded as promising precursoryinformation that could help signal the arrival of large earthquakes. TheGutenberg-Richter relationship (GRR) should allow extrapolation ofseismicity changes down to seismic noise level magnitudes. Thishypothesis is verified by comparison of seismic noise at 80 Hz with theParkfield M4 1993-1994 series, where noise peaks 5 months before theseries to about twice the background level.

  10. Identification of selected in vitro generated phase-I metabolites of the steroidal selective androgen receptor modulator MK-0773 for doping control purposes.

    PubMed

    Lagojda, Andreas; Kuehne, Dirk; Krug, Oliver; Thomas, Andreas; Wigger, Tina; Karst, Uwe; Schänzer, Wilhelm; Thevis, Mario

    2016-01-01

    Research into developing anabolic agents for various therapeutic purposes has been pursued for decades. As the clinical utility of anabolic-androgenic steroids has been found to be limited because of their lack of tissue selectivity and associated off-target effects, alternative drug entities have been designed and are commonly referred to as selective androgen receptor modulators (SARMs). While most of these SARMs are of nonsteroidal structure, the drug candidate MK-0773 comprises a 4-aza-steroidal nucleus. Besides the intended therapeutic use, SARMs have been found to be illicitly distributed and misused as doping agents in sport, necessitating frequently updated doping control analytical assays. As steroidal compounds reportedly undergo considerable metabolic transformations, the phase-I metabolism of MK-0773 was simulated using human liver microsomal (HLM) preparations and electrochemical conversion. Subsequently, major metabolic products were identified and characterized employing liquid chromatography-high-resolution/high- accuracy tandem mass spectrometry with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) as well as nuclear magnetic resonance (NMR) spectroscopy. MK-0773 produced numerous phase-I metabolites under the chosen in vitro incubation reactions, mostly resulting from mono- and bisoxygenation of the steroid. HLM yielded at least 10 monooxygenated species, while electrochemistry-based experiments resulted predominantly in three monohydroxylated metabolites. Elemental composition data and product ion mass spectra were generated for these analytes, ESI/APCI measurements corroborated the formation of at least two N-oxygenated metabolites, and NMR data obtained from electrochemistry-derived products supported structures suggested for three monohydroxylated compounds. Hereby, the hydroxylation of the A-ring located N- bound methyl group was found to be of particular intensity. In the absence of controlled elimination studies, the

  11. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  12. Selective peroxisome proliferator-activated receptorα modulators (SPPARMα): The next generation of peroxisome proliferator-activated receptor α-agonists

    PubMed Central

    2013-01-01

    Dyslipidemia is a major risk factor for cardiovascular (CV) disease – the primary cause of death, worldwide. Although reducing levels of low-density lipoprotein-cholesterol can significantly reduce CV risk, a high level of residual risk persists, especially in people with obesity-related conditions, such as metabolic syndrome and type 2 diabetes mellitus. Peroxisome proliferator-activated receptor alpha- (PPARα-) agonists (e.g. fibrates), play a central role in the reduction of macro- and microvascular risk in these patients. However, the currently available fibrates are weak (PPARα-agonists) with limited efficacy due to dose-related adverse effects. To address this problem, a new generation of highly potent and selective PPARα-modulators (SPPARMα) is being developed that separate the benefits of the PPARα-agonists from their unwanted side effects. Among these, aleglitazar (a dual PPARα/γ agonist) and GFT505 (a dual PPAR α/δ agonist) have recently entered late-phase development. Although both compounds are more potent PPARα-activators than fenofibrate in vitro, only aleglitezar is more effective in lowering triglycerides and raising high-density lipoprotein-cholesterol (HDL-C) in humans. However, it is also associated with a potential risk of adverse effects. More recently, a highly potent, specific PPARα-agonist (K-877) has emerged with SPPARMα characteristics. Compared to fenofibrate, K-877 has more potent PPARα-activating efficacy in vitro, greater effects on triglycerides- and HDL-C levels in humans, and a reduced risk of adverse effects. If successful, K-877 has the potential to supersede the fibrates as the treatment of choice for patients with residual CV risk associated with metabolic syndrome and type 2 diabetes. PMID:23721199

  13. Cell surface-expressed moesin-like receptor regulates T cell interactions with tissue components and binds an adhesion-modulating IL-2 peptide generated by elastase.

    PubMed

    Ariel, A; Hershkoviz, R; Altbaum-Weiss, I; Ganor, S; Lider, O

    2001-03-01

    The adhesion of leukocytes to the extracellular matrix (ECM) depends on their responses to variations in the chemotactic signals in their milieu, as well as on the functioning of cytoskeletal and context-specific receptors. Ezrin, radixin, and moesin constitute a family of proteins that link the plasma membrane to the actin cytoskeleton. The surface expression of moesin on T cells and its role in cell adhesion has not been fully elucidated. Recently, we found that IL-2 peptides generated by elastase modified the adhesion of activated T cells to ECM ligands. Here, we further examined the adhesion regulatory effects of EFLNRWIT, one of the IL-2 peptides, as well as the existence and putative function of its receptor on T cells. We found that when presented to T cells in the absence of another activator, the EFLNRWIT peptide induced cell adhesion to vessel wall and ECM components. Binding of a radiolabeled peptide to T cells, precipitation with the immobilized peptide, and amino acid sequencing of the precipitated protein revealed that EFLNRWIT exerts its function via a cell surface-expressed moesin-like moiety, whose constitutive expression on T cells was increased after activation. This notion was further supported by our findings that: 1) anti-moesin mAb inhibited the binding of T cells to the immobilized EFLNRWIT peptide, 2) immobilized recombinant moesin bound the IL-2 peptide, and 3) soluble moesin inhibited the EFLNRWIT-induced T cell adhesion to fibronectin. Interestingly, moesin appears to be generally involved in T cell responses to adhesion-regulating signals. Thus, the IL-2 peptide EFLNRWIT appears to exert its modulating capacities via an adhesion-regulating moesin-like receptor. PMID:11207255

  14. Identification of selected in vitro generated phase-I metabolites of the steroidal selective androgen receptor modulator MK-0773 for doping control purposes.

    PubMed

    Lagojda, Andreas; Kuehne, Dirk; Krug, Oliver; Thomas, Andreas; Wigger, Tina; Karst, Uwe; Schänzer, Wilhelm; Thevis, Mario

    2016-01-01

    Research into developing anabolic agents for various therapeutic purposes has been pursued for decades. As the clinical utility of anabolic-androgenic steroids has been found to be limited because of their lack of tissue selectivity and associated off-target effects, alternative drug entities have been designed and are commonly referred to as selective androgen receptor modulators (SARMs). While most of these SARMs are of nonsteroidal structure, the drug candidate MK-0773 comprises a 4-aza-steroidal nucleus. Besides the intended therapeutic use, SARMs have been found to be illicitly distributed and misused as doping agents in sport, necessitating frequently updated doping control analytical assays. As steroidal compounds reportedly undergo considerable metabolic transformations, the phase-I metabolism of MK-0773 was simulated using human liver microsomal (HLM) preparations and electrochemical conversion. Subsequently, major metabolic products were identified and characterized employing liquid chromatography-high-resolution/high- accuracy tandem mass spectrometry with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) as well as nuclear magnetic resonance (NMR) spectroscopy. MK-0773 produced numerous phase-I metabolites under the chosen in vitro incubation reactions, mostly resulting from mono- and bisoxygenation of the steroid. HLM yielded at least 10 monooxygenated species, while electrochemistry-based experiments resulted predominantly in three monohydroxylated metabolites. Elemental composition data and product ion mass spectra were generated for these analytes, ESI/APCI measurements corroborated the formation of at least two N-oxygenated metabolites, and NMR data obtained from electrochemistry-derived products supported structures suggested for three monohydroxylated compounds. Hereby, the hydroxylation of the A-ring located N- bound methyl group was found to be of particular intensity. In the absence of controlled elimination studies, the

  15. Growth of a Structure Connecting the 2010 M 7.2 El Mayor - Cucapah Rupture with the Elsinore Faul

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Parker, J. W.

    2015-12-01

    The M 7.2 El Mayor - Cucapah earthquake occurred on 4 April 2010 in the northern part of Baja, Mexico. The rupture extended about 120 km from near the northern tip of the Gulf of California to the US - Mexican border south of the Elsinore fault zone. Most of the aftershocks occurred within days of the main event. On 14 June 2010 a M 5.7 late aftershock occurred 8 km southeast of Ocotillo, CA and is the largest aftershock in the sequence. The right-lateral event occurred in a cluster of aftershocks and was followed by its own aftershock sequence. UAVSAR data were collected for a swath covering the aftershock on 13 April, 2010 just after the El Mayor - Cucapah earthquake and before the earthquake on 21 October 2009. The line was reflown 1 July 2010 after the M 5.7 14 June 2010 aftershock. Data have been continued to be collected semi yearly to yearly since then. Repeat Pass Interferomety (RPI) products spanning the aftershock show the growth of a lineament that with an azimuth of 121.5° or a strike of -58.5°. The interferograms suggest that a stepover develops following the earthquake. The epicenter of the M 5.7 aftershock is proximal to the linear discontinuity in the postseismic interferogram and the mechanism of the event is consistent with slip on this stepover. Inversions for slip on the northeast linear structure that steps west of the mainshock rupture yield a moment magnitude ranging from 5.5 - 5.8, which is consistent with the magnitude of the aftershock. Slip occurs at a depth of 2-10 km on a steeply dipping fault.

  16. Exponential decline of aftershocks of the M7.9 1868 great Kau earthquake, Hawaii, through the 20th century

    USGS Publications Warehouse

    Klein, F.W.; Wright, Tim

    2008-01-01

    The remarkable catalog of Hawaiian earthquakes going back to the 1820s is based on missionary diaries, newspaper accounts, and instrumental records and spans the great M7.9 Kau earthquake of April 1868 and its aftershock sequence. The earthquake record since 1868 defines a smooth curve complete to M5.2 of the declining rate into the 21st century, after five short volcanic swarms are removed. A single aftershock curve fits the earthquake record, even with numerous M6 and 7 main shocks and eruptions. The timing of some moderate earthquakes may be controlled by magmatic stresses, but their overall long-term rate reflects one of aftershocks of the Kau earthquake. The 1868 earthquake is, therefore, the largest and most controlling stress event in the 19th and 20th centuries. We fit both the modified Omori (power law) and stretched exponential (SE) functions to the earthquakes. We found that the modified Omori law is a good fit to the M ??? 5.2 earthquake rate for the first 10 years or so and the more rapidly declining SE function fits better thereafter, as supported by three statistical tests. The switch to exponential decay suggests that a possible change in aftershock physics may occur from rate and state fault friction, with no change in the stress rate, to viscoelastic stress relaxation. The 61-year exponential decay constant is at the upper end of the range of geodetic relaxation times seen after other global earthquakes. Modeling deformation in Hawaii is beyond the scope of this paper, but a simple interpretation of the decay suggests an effective viscosity of 1019 to 1020 Pa s pertains in the volcanic spreading of Hawaii's flanks. The rapid decline in earthquake rate poses questions for seismic hazard estimates in an area that is cited as one of the most hazardous in the United States.

  17. Modelling macroseismic observations for historical earthquakes: the cases of the M = 7.0, 1954 Sofades and M = 6.8, 1957 Velestino events (central Greece)

    NASA Astrophysics Data System (ADS)

    Papazachos, Giannis; Papazachos, Costas; Skarlatoudis, Andreas; Kkallas, Harris; Lekkas, Efthimios

    2016-01-01

    We attempt to model the spatial distribution of the strong ground motion for the large M = 7.0, 1954 Sofades and M = 6.8, 1957 Velestino events (southern Thessaly basin, central Greece), using the macroseismic intensities ( I M M up to 9+) observed within the broader Thessaly area. For this reason, we employ a modified stochastic method realised by the EXSIM algorithm for extended sources, in order to reproduce the damage distribution of these earthquakes, in an attempt to combine existing earthquake information and appropriate scaling relations with surface geology and to investigate the efficiency of the available macroseismic data. For site-effects assessment, we use a new digital geological map of the broader Thessaly basin, where geological formations are grouped by age and mapped on appropriate NEHRP soil classes. Using the previous approach, we estimate synthetic time series for different rupture scenarios and employ various calibrating relations between PGA/PGV and macroseismic intensity, allowing the generation of synthetic (stochastic) isoseismals. Also, different site amplification factors proposed for the broader Aegean area, according to local geology, are tested. Finally, we also perform a sensitivity analysis of the fault location, taking into account the available neotectonic data for the broader southern Thessaly fault zone. The finally determined fault locations are different than previously proposed, in agreement with the available neotectonic information. The observed macroseismic intensities are in good agreement with the ones derived from the synthetic waveforms, verifying both the usefulness of the approach, as well as of the macroseismic data used. Finally, site-effects show clear correlation with the geological classification employed, with constant amplification factors for each soil class generally providing better results than generic transfer functions.

  18. Thermoelectric power generator module of 16x16 Bi{sub 2}Te{sub 3} and 0.6%ErAs:(InGaAs){sub 1-x}(InAlAs){sub x} segmented elements

    SciTech Connect

    Zeng Gehong; Bahk, Je-Hyeong; Bowers, John E.; Lu Hong; Gossard, Arthur C.; Singer, Suzanne L.; Majumdar, Arun; Bian, Zhixi; Zebarjadi, Mona; Shakouri, Ali

    2009-08-24

    We report the fabrication and characterization of thermoelectric power generator modules of 16x16 segmented elements consisting of 0.8 mm thick Bi{sub 2}Te{sub 3} and 50 {mu}m thick ErAs:(InGaAs){sub 1-x}(InAlAs){sub x} with 0.6% ErAs by volume. An output power up to 6.3 W was measured when the heat source temperature was at 610 K. The thermoelectric properties of (InGaAs){sub 1-x}(InAlAs){sub x} were characterized from 300 up to 830 K. The finite element modeling shows that the performance of the generator modules can further be enhanced by improving the thermoelectric properties of the element materials, and reducing the electrical and thermal parasitic losses.

  19. The M=7.9 Alaska Earthquake of 3 November 2002: Felt Reports and Unusual Effects Across Western Canada

    NASA Astrophysics Data System (ADS)

    Cassidy, J. F.; Rogers, G. C.; Bird, A. L.; Mulder, T. L.

    2002-12-01

    The 3 November 2002 M=7.9 Alaska earthquake was one of the largest earthquakes recorded in North America during the past 100 years. This earthquake occurred at 2:12 p.m. PST (on a Sunday) and was located 330 km to the west of the Yukon-Alaska border. Surface rupture and aftershocks extended to within about 100 km of the Canadian border. More than 250 "felt" reports were submitted to the Geological Survey of Canada website (http://www.pgc.nrcan.gc.ca/seismo/table.htm) within a few days of the earthquake. Here, we summarize those reports which include typical high-frequency shaking effects to distances of about 1500 km, as well as numerous long-period effects, such as human effects (nausea), swaying highrises, telephone poles and chandeliers, seiches in lakes and inlets, water sloshing from swimming pools, and instances of dirty well-water to distances of nearly 3500 km across Western Canada. Felt intensities (MMI)of about IV were observed across the Yukon Territory at distances of 350 km to 750 km. There were a few reports of minor damage in this region, as well as numerous reports of items knocked from shelves and parked vehicles rocking noticeably. The most distant felt reports in western Canada were from southern Alberta (2400 km distance) where people in highrises felt the swaying. More than 30 reports of human effects were received. These ranged from people feeling dizzy, seasick or nauseated (to distances of 2400 km), to difficulty standing and maintaining balance (to distances of 1000 km). Long-period effects of houses "swaying", large signs flexing, and telephone poles and tall trees swaying were reported to distances of more than 1000 km. Swinging of chandeliers, hanging plants and lights were reported to distances of 2400 km. There were more than 30 reports of seiches. Most reports came from southern British Columbia (2200-2400 km) where, although no ground shaking was noticed, water surges up to 1 m were observed. In one case a cabin held by cables near

  20. The first recorded surface rupture in southern Africa: the 22 February 2006 M 7.0 Machaze, Mozambique, earthquake

    NASA Astrophysics Data System (ADS)

    Fenton, C. H.

    2006-12-01

    A major (M 7.0) earthquake occurred on 22 February 2006 at 22:19 UTC in the western province of Manica in Mozambique, southern Africa. The epicenter was located in Machaze, the southernmost district of Manica province, about 45 km due south of the district capital of Chitobe. The earthquake was felt throughout eastern southern Africa but caused surprisingly little damage and a very small number of casualties. Surface rupture was mapped along the NNW-striking Machaze fault and liquefaction was observed throughout the epicentral region. This is the largest earthquake to have occurred in Mozambique in historical time. The surface-rupture along the Machaze fault is generally linear, without significant topographic deviation, indicating that the fault plane is relatively steep. Displacement is normal, down-to-the-west on west-dipping fault plane. The fault rupture is marked by a series of west-facing fault scarps developed in Holocene sandy alluvium. Vertical separation across the fault scarp ranges between 0.4 m and 2.05 m. At one location, pre- existing trails crossing the fault form piercing points that indicate a component of left-lateral strike-slip displacement of up to 0.7 m. To date we have only observed part of the surface rupture along a fault length of 15 km. Time constraints and the presence of minefields have prevented full investigation of the surface rupture. The total rupture length is estimated to be on the order of 30-40 km based on the regression equations between earthquake magnitude and surface rupture length and from the time function duration from preliminary waveform inversion for the mainshock. The surface rupture was developed in a broad, flat alluvial plain, with no apparent pre-existing fault-related geomorphology. However, with the benefit of hindsight, very subdued features, including vegetation lineaments and areas of ponded sediment that appear to define a lineament along part of the trace of the surface rupture are observed on pre

  1. Early post-seismic deformation due to the 2015 M7.8 Gorkha (Nepal) earthquake: Constraints on rheology of the Tibetan lithosphere

    NASA Astrophysics Data System (ADS)

    Fialko, Y. A.; Wang, K.

    2015-12-01

    Over the last decade several major earthquakes have occurred on faultsbounding the Tibetan plateau, including the 2005 M7.6 Kashmir(Pakistan), the 2008 M7.8 Wenchuan (China), and the 2015 M7.8 Gorkha(Nepal) earthquakes. Time-dependent surface deformation followingthese earthquakes provides important constraints on the effectiverheology of the lower crust and upper mantle beneath Tibet. Theepicentral area of the 2015 Gorkha (Nepal) earthquake has beenexceptionally well imaged by several Interferometric SyntheticAperture Radar (InSAR) satellites including ALOS-2 (Japanese SpaceAgency) and Sentinel-1 (European Space Agency) missions. We willpresent observations of surface deformation in the early (severalmonths) postseismic period following the 2015 Gorkha earthquake, andcompare surface deformation data to numerical models of postseismictransients assuming various relaxation mechanisms. We will alsocompare the postseismic deformation data from different earthquakes atthe boundaries of the Tibetan Plateau to evaluate the effects oflateral heterogeneities in rheological properties of the ductilesubstrate.

  2. Modulating the generation of long-lived charge separated states exclusively from the triplet excited states in palladium porphyrin-fullerene conjugates

    NASA Astrophysics Data System (ADS)

    O. Obondi, Christopher; Lim, Gary N.; Churchill, Brittani; Poddutoori, Prashanth K.; van der Est, Art; D'Souza, Francis

    2016-04-01

    This study demonstrates molecular engineering of a series of donor-acceptor systems to allow control of the lifetime and initial spin multiplicity of the charge-separated state. By tuning the rate of intersystem crossing (ISC) and the donor-acceptor distance, electron transfer can be made to occur exclusively from the triplet excited state of the electron donor resulting in long-lived charge separation. To achieve this, three new palladium porphyrin-fullerene donor-acceptor systems were synthesized. The heavy Pd atom enhances the rate of ISC in the porphyrin and the rates of electron and energy transfer are modulated by varying the redox potential of the porphyrin and the porphyrin-fullerene distance. In the case of the meso-tris(tolyl)porphyrinato palladium(ii)-fulleropyrrolidine, the donor-acceptor distance is relatively long (13.1 Å) and the driving force for electron transfer is low. As a result, excitation of the porphyrin leads to rapid ISC followed by triplet-triplet energy transfer to fullerene. When the fullerene is bound directly to the porphyrin shortening the donor-acceptor distance to 2.6 Å electron transfer from the singlet excited palladium porphyrin leading to the generation of a short-lived charge separated state is the main process. Finally, when the palladium porphyrin is substituted with three electron rich triphenylamine entities, the lower oxidation potential of the porphyrin and appropriate donor-acceptor distance (~13 Å), lead to electron transfer exclusively from the triplet excited state of palladium porphyrin with high quantum yield. The results show that when electron transfer occurs from the triplet state, its increased lifetime allows the distance between the donor and acceptor to be increased which results in a longer lifetime for the charge separated state.This study demonstrates molecular engineering of a series of donor-acceptor systems to allow control of the lifetime and initial spin multiplicity of the charge-separated state

  3. Comparison of the Structurally Controlled Landslides Numerical Model Results to the M 7.2 2013 Bohol Earthquake Co-seismic Landslides

    NASA Astrophysics Data System (ADS)

    Macario Galang, Jan Albert; Narod Eco, Rodrigo; Mahar Francisco Lagmay, Alfredo

    2015-04-01

    The M 7.2 October 15, 2013 Bohol earthquake is the most destructive earthquake to hit the Philippines since 2012. The epicenter was located in Sagbayan municipality, central Bohol and was generated by a previously unmapped reverse fault called the "Inabanga Fault". Its name, taken after the barangay (village) where the fault is best exposed and was first seen. The earthquake resulted in 209 fatalities and over 57 billion USD worth of damages. The earthquake generated co-seismic landslides most of which were related to fault structures. Unlike rainfall induced landslides, the trigger for co-seismic landslides happen without warning. Preparedness against this type of landslide therefore, relies heavily on the identification of fracture-related unstable slopes. To mitigate the impacts of co-seismic landslide hazards, morpho-structural orientations or discontinuity sets were mapped in the field with the aid of a 2012 IFSAR Digital Terrain Model (DTM) with 5-meter pixel resolution and < 0.5 meter vertical accuracy. Coltop 3D software was then used to identify similar structures including measurement of their dip and dip directions. The chosen discontinuity sets were then keyed into Matterocking software to identify potential rock slide zones due to planar or wedged discontinuities. After identifying the structurally-controlled unstable slopes, the rock mass propagation extent of the possible rock slides was simulated using Conefall. The results were compared to a post-earthquake landslide inventory of 456 landslides. Out the total number of landslides identified from post-earthquake high-resolution imagery, 366 or 80% intersect the structural-controlled hazard areas of Bohol. The results show the potential of this method to identify co-seismic landslide hazard areas for disaster mitigation. Along with computer methods to simulate shallow landslides, and debris flow paths, located structurally-controlled unstable zones can be used to mark unsafe areas for settlement. The

  4. Expression of M6 and M7 lysin in Mytilus edulis is not restricted to sperm, but occurs also in oocytes and somatic tissue of males and females.

    PubMed

    Heß, Anne-Katrin; Bartel, Manuela; Roth, Karina; Messerschmidt, Katrin; Heilmann, Katja; Kenchington, Ellen; Micheel, Burkhard; Stuckas, Heiko

    2012-08-01

    Sperm proteins of marine sessile invertebrates have been extensively studied to understand the molecular basis of reproductive isolation. Apart from molecules such as bindin of sea urchins or lysin of abalone species, the acrosomal protein M7 lysin of Mytilus edulis has been analyzed. M7 lysin was found to be under positive selection, but mechanisms driving the evolution of this protein are not fully understood. To explore functional aspects, this study investigated the protein expression pattern of M7 and M6 lysin in gametes and somatic tissue of male and female M. edulis. The study employs a previously published monoclonal antibody (G26-AG8) to investigate M6 and M7 lysin protein expression, and explores expression of both genes. It is shown that these proteins and their encoding genes are expressed in gametes and somatic tissue of both sexes. This is in contrast to sea urchin bindin and abalone lysin, in which gene expression is strictly limited to males. Although future studies need to clarify the functional importance of both acrosomal proteins in male and female somatic tissue, new insights into the evolution of sperm proteins in marine sessile invertebrates are possible. This is because proteins with male-specific expression (bindin, lysin) might evolve differently than proteins with expression in both sexes (M6/M7 lysin), and the putative function of both proteins in females opens the possibility that the evolution of M6/M7 lysin is under sexual antagonistic selection, for example, mutations beneficial to the acrosomal function that are less beneficial the function in somatic tissue of females. PMID:22674895

  5. Modulated curvaton decay

    SciTech Connect

    Assadullahi, Hooshyar; Wands, David; Firouzjahi, Hassan; Namjoo, Mohammad Hossein E-mail: firouz@mail.ipm.ir E-mail: david.wands@port.ac.uk

    2013-03-01

    We study primordial density perturbations generated by the late decay of a curvaton field whose decay rate may be modulated by the local value of another isocurvature field, analogous to models of modulated reheating at the end of inflation. We calculate the primordial density perturbation and its local-type non-Gaussianity using the sudden-decay approximation for the curvaton field, recovering standard curvaton and modulated reheating results as limiting cases. We verify the Suyama-Yamaguchi inequality between bispectrum and trispectrum parameters for the primordial density field generated by multiple field fluctuations, and find conditions for the bound to be saturated.

  6. Lipopolysaccharide modulation of dendritic cells is insufficient to mature dendritic cells to generate CTLs from naive polyclonal CD8+ T cells in vitro, whereas CD40 ligation is essential.

    PubMed

    Kelleher, M; Beverley, P C

    2001-12-01

    Many cytotoxic CD8+ T cell responses are dependent on the interactions between CD40 ligand on the helper CD4+ T cell and CD40 on the APC. Although CD40 triggering of dendritic cells (DC) has been shown to mature the DC by increasing the level of expression of costimulatory molecules and inducing IL-12 secretion, the precise mechanisms by which CD40-CD40 ligand interactions allow DC to drive CTL responses remain unknown. We have used an in vitro model in which naive polyclonal CD8+ T cells can be activated by bone marrow-derived DC to investigate factor(s) that are responsible for this CD40-dependent generation of CTLs. DC modulated with agonistic anti-CD40 mAb (aCD40) are able to generate Ag-specific CTL responses while DC modulated with the microbial stimulus LPS alone do not. We compared the Ag-presenting capacity, levels of costimulatory molecules, and release of cytokines and chemokines of DC modulated with aCD40 to that of DC modulated by LPS. None of the factors assayed account for the unique capacity of anti-CD40-matured DC to drive CTL but this model provides a simplified system for further investigation. Although we attempted to use an LPS-free system for these studies, we are unable to rule out the possibility that very low levels of endotoxin (<20 pg/ml) may synergize with CD40 ligation in the generation of CTLs. PMID:11714787

  7. The 2007 M7.7 Tocopilla northern Chile earthquake sequence - along and across strike rupture segmentation

    NASA Astrophysics Data System (ADS)

    Schurr, B.; Asch, G.; Motagh, M.; Oncken, O.; Chong Diaz, G.; Barrientos, S. E.; Vilotte, J.

    2010-12-01

    In November 2007 a M7.7 earthquake occurred near the coastal town of Tocopilla in the southern part of a presumed seismic gap extending some 500 km along the northern Chile subduction zone. This major segment last broke in a magnitude ≧8.5 earthquake in 1877. Assuming a complete lock of the interface, it has accumulated more than 8 m of slip deficit. The contiguous segments to the north and south broke in M≧8 earthquakes in 2001 and 1995. Teams from Chile (Universidad Católica del Norte and Universidad de Chile), France (IPGP) and Germany (GFZ) started in 2006 to install semi-permanent multi-parameter observatories within the Integrated Plate Boundary Observatory Chile (IPOC) Initiative to monitor deformation at a variety of spatial and temporal scales in the final stage of the seismic cycle. At the time of the Tocopilla earthquake, 12 sites were equipped with seismic broadband and strong-motion sensors recording both the mainshock and its aftershock series. The earthquake rupture extended for about 160 km from the centre of the Mejillones peninsula (MP) to about 20 km north of the town of Tocopilla. Slip was confined to the depth range 30-55 km and concentrated in two patches in the north and south with a maximum of about 2.6 m. Hence the earthquake released only a fraction of the slip deficit and broke only the down-dip part of the plate interface, with the up-dip limit of the rupture approximately following the coastline. This poses the important question why rupture did not extend offshore, where the interface is presumably locked based on models of long-term interseismic deformation. We relocated more than 1000 aftershocks occurring in the week following the mainshock using hand-picked arrival times, cross-correlation based differential travel times and the double-difference algorithm. Despite the sparseness of the network, the aftershocks sharply define the plate interface. Seismicity in the first 24h is congruent to the slip distribution with the area

  8. Stress rotations due to the M6.5 foreshock and M7.3 main shock in the 2016 Kumamoto, SW Japan, earthquake sequence

    NASA Astrophysics Data System (ADS)

    Yoshida, Keisuke; Hasegawa, Akira; Saito, Tatsuhiko; Asano, Youichi; Tanaka, Sachiko; Sawazaki, Kaoru; Urata, Yumi; Fukuyama, Eiichi

    2016-10-01

    A shallow M7.3 event with a M6.5 foreshock occurred along the Futagawa-Hinagu fault zone in Kyushu, SW Japan. We investigated the spatiotemporal variation of the stress orientations in and around the source area of this 2016 Kumamoto earthquake sequence by inverting 1218 focal mechanisms. The results show that the σ3 axis in the vicinity of the fault plane significantly rotated counterclockwise after the M6.5 foreshock and rotated clockwise after the M7.3 main shock in the Hinagu fault segment. This observation indicates that a significant portion of the shear stress was released both by the M6.5 foreshock and M7.3 main shock. It is estimated that the stress release by the M6.5 foreshock occurred in the shallower part of the Hinagu fault segment, which brought the stress concentration in its deeper part. This might have caused the M7.3 main shock rupture mainly along the deeper part of the Hinagu fault segment after 28 h.

  9. Earthquake source imaging by high-resolution array analysis at regional distances: the 2010 M7 Haiti earthquake as seen by the Venezuela National Seismic Network

    NASA Astrophysics Data System (ADS)

    Meng, L.; Ampuero, J. P.; Rendon, H.

    2010-12-01

    Back projection of teleseismic waves based on array processing has become a popular technique for earthquake source imaging,in particular to track the areas of the source that generate the strongest high frequency radiation. The technique has been previously applied to study the rupture process of the Sumatra earthquake and the supershear rupture of the Kunlun earthquakes. Here we attempt to image the Haiti earthquake using the data recorded by Venezuela National Seismic Network (VNSN). The network is composed of 22 broad-band stations with an East-West oriented geometry, and is located approximately 10 degrees away from Haiti in the perpendicular direction to the Enriquillo fault strike. This is the first opportunity to exploit the privileged position of the VNSN to study large earthquake ruptures in the Caribbean region. This is also a great opportunity to explore the back projection scheme of the crustal Pn phase at regional distances,which provides unique complementary insights to the teleseismic source inversions. The challenge in the analysis of the 2010 M7.0 Haiti earthquake is its very compact source region, possibly shorter than 30km, which is below the resolution limit of standard back projection techniques based on beamforming. Results of back projection analysis using the teleseismic USarray data reveal little details of the rupture process. To overcome the classical resolution limit we explored the Multiple Signal Classification method (MUSIC), a high-resolution array processing technique based on the signal-noise orthognality in the eigen space of the data covariance, which achieves both enhanced resolution and better ability to resolve closely spaced sources. We experiment with various synthetic earthquake scenarios to test the resolution. We find that MUSIC provides at least 3 times higher resolution than beamforming. We also study the inherent bias due to the interferences of coherent Green’s functions, which leads to a potential quantification

  10. Tsunami modelling and source constraints from regional tide-gages and tilt measurements for the 2008 M=7.5, Tocopilla subduction earthquake

    NASA Astrophysics Data System (ADS)

    Hébert, H.; Boudin, F.; Bernard, P.; Peyrat, S.; Bejarpi, M.

    2008-12-01

    We focus on the small tsunami (a few tens of cm) generated by the November 2007, M=7.5 Tocopilla earthquake, which ruptured about 140 km of the southernmost part of the major, 1000 km long seismic gap of the northern Chile subduction. We first use the available regional tide-gage records, within 1000 km, at coastal stations and on nearby DART buoys (source of data: SHOA, Chile; University of Hawai; NOAA/NBDC) , to constrain the offshore, up-dip extension of the rupture, poorly constrained by the on-land records (GPS, InSAR, accelerograms). For this purpose, various source models, compatible with the geodetic/seismological data, are used as input for numerical calculations, including the best-fit, minimal seismological and geodetic inverted models. The vertical static displacement of the ocean floor is calculated using uniform, instantaneous dislocations in an elastic half-space. The tsunami wave is calculated using a finite-difference scheme solving the hydrodynamic equations, under the non linear shallow water assumption. Bathymetric data derived from the 1' GEBCO dataset are used. The time and amplitude of the first oscillations at the closest tide-gages constrain the offshore part of the source. The later part of the signal is persistent during more than one day, with dominant period of 40 to 45 minutes. Numerical simulation correctly reproduces these spectral characteristic as well as the persistence of the waves, which appear to be trapped within a narrow band (50 to 70 km wide) along at least the 800 km long coastline of the model, suggesting a very efficient trapping by the shallow area between the trench and the coast. This characteristic period was already present for previous tsunamis in this area (2001,1995,1877 major earthquakes) . At 200 to 300 km north to the epicentral area, tilt records from a long base tiltmeter and from broad-band seismometers (STS2) of the IPOC array, installed at short distances from the coast (3 to 25 km), show a clear signal

  11. Method of monolithic module assembly

    DOEpatents

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-01-01

    Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  12. Landslides caused by the M 7.6 Tecomán, Mexico earthquake of January 21, 2003

    USGS Publications Warehouse

    Keefer, David K.; Wartman, Joseph; Navarro, Ochoa C.; Rodriguez-Marek, Adrian; Wieczorek, Gerald F.

    2006-01-01

    In contrast to the coastal cordilleras, the volcanic rocks to the north were more susceptible to the occurrence of seismically triggered landslides. The greatest number and concentrations of landslides occurred there, and the landslides were larger than those in the coastal cordilleras, even though this volcanic terrain was farther from the earthquake source. Here, stretches of river bluffs several hundred meters long had been stripped of vegetation and surficial material by coalescing landslides, and several days after the main shock, thousands of small rock falls were still occurring each day, indicating an ongoing hazard. The high susceptibility of volcanic materials to earthquake-generated landslides conforms to findings in other recent earthquakes.

  13. The modulation of action potential generation by calcium-induced calcium release is enhanced by mitochondrial inhibitors in mudpuppy parasympathetic neurons.

    PubMed

    Barstow, K L; Locknar, S A; Merriam, L A; Parsons, R L

    2004-01-01

    Previously, we demonstrated that outward currents activated by calcium-induced calcium release (CICR) opposed depolarization-induced action potential (AP) generation in dissociated mudpuppy parasympathetic neurons [J Neurophysiol 88 (2002) 1119]. In the present study, we tested whether AP generation by depolarizing current ramps could be altered by dissipating the mitochondrial membrane potential and thus interrupting mitochondrial Ca2+ buffering. Exposure to the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP; 2 microM) alone or in combination with the mitochondrial ATP synthase inhibitor oligomycin (8 microg/ml), increased the latency to AP generation. Exposure to the electron transport chain inhibitor rotenone (10 microM) alone or in combination with oligomycin (8 microg/ml) similarly increased the latency to AP generation. CCCP and oligomycin or rotenone and oligomycin treatment caused rhodamine 123 loss from mitochondria within a few minutes, confirming that the mitochondrial membrane potential was dissipated during drug exposure. Oligomycin alone had no effect on the latency to AP generation and did not cause loss of rhodamine 123 from mitochondria. The increase in latency induced by CCCP and oligomycin was similar when recordings were made with either the perforated patch or standard whole cell patch recording configuration. Exposure to the endoplasmic reticulum Ca-ATPase inhibitor thapsigargin (1 microM), decreased the latency to AP generation. In cells pretreated with thapsigargin to eliminate CICR, CCCP and oligomycin had no effect on AP latency. Pretreatment with iberiotoxin (IBX; 100 nM), an inhibitor of large conductance, calcium- and voltage-activated potassium channels, reduced the extent of the CCCP- and oligomycin-induced increase in latency to AP generation. These results indicate that treatment with CCCP or rotenone to dissipate the mitochondrial membrane potential, a condition which should minimize sequestration of Ca2+ by

  14. Sequence-structure-function relationships of a tRNA (m7G46) methyltransferase studied by homology modeling and site-directed mutagenesis.

    PubMed

    Purta, Elzbieta; van Vliet, Françoise; Tricot, Catherine; De Bie, Lara G; Feder, Marcin; Skowronek, Krzysztof; Droogmans, Louis; Bujnicki, Janusz M

    2005-05-15

    The Escherichia coli TrmB protein and its Saccharomyces cerevisiae ortholog Trm8p catalyze the S-adenosyl-L-methionine-dependent formation of 7-methylguanosine at position 46 (m7G46) in tRNA. To learn more about the sequence-structure-function relationships of these enzymes we carried out a thorough bioinformatics analysis of the tRNA:m7G methyltransferase (MTase) family to predict sequence regions and individual amino acid residues that may be important for the interactions between the MTase and the tRNA substrate, in particular the target guanosine 46. We used site-directed mutagenesis to construct a series of alanine substitutions and tested the activity of the mutants to elucidate the catalytic and tRNA-recognition mechanism of TrmB. The functional analysis of the mutants, together with the homology model of the TrmB structure and the results of the phylogenetic analysis, revealed the crucial residues for the formation of the substrate-binding site and the catalytic center in tRNA:m7G MTases.

  15. Optical modulator system

    NASA Technical Reports Server (NTRS)

    Brand, J.

    1972-01-01

    The fabrication, test, and delivery of an optical modulator system which will operate with a mode-locked Nd:YAG laser indicating at either 1.06 or 0.53 micrometers is discussed. The delivered hardware operates at data rates up to 400 Mbps and includes a 0.53 micrometer electrooptic modulator, a 1.06 micrometer electrooptic modulator with power supply and signal processing electronics with power supply. The modulators contain solid state drivers which accept digital signals with MECL logic levels, temperature controllers to maintain a stable thermal environment for the modulator crystals, and automatic electronic compensation to maximize the extinction ratio. The modulators use two lithium tantalate crystals cascaded in a double pass configuration. The signal processing electronics include encoding electronics which are capable of digitizing analog signals between the limit of + or - 0.75 volts at a maximum rate of 80 megasamples per second with 5 bit resolution. The digital samples are serialized and made available as a 400 Mbps serial NRZ data source for the modulators. A pseudorandom (PN) generator is also included in the signal processing electronics. This data source generates PN sequences with lengths between 31 bits and 32,767 bits in a serial NRZ format at rates up to 400 Mbps.

  16. Spatial Terahertz Modulator

    NASA Astrophysics Data System (ADS)

    Xie, Zhenwei; Wang, Xinke; Ye, Jiasheng; Feng, Shengfei; Sun, Wenfeng; Akalin, Tahsin; Zhang, Yan

    2013-11-01

    Terahertz (THz) technology is a developing and promising candidate for biological imaging, security inspection and communications, due to the low photon energy, the high transparency and the broad band properties of the THz radiation. However, a major encountered bottleneck is lack of efficient devices to manipulate the THz wave, especially to modulate the THz wave front. A wave front modulator should allow the optical or electrical control of the spatial transmission (or reflection) of an input THz wave and hence the ability to encode the information in a wave front. Here we propose a spatial THz modulator (STM) to dynamically control the THz wave front with photo-generated carriers. A computer generated THz hologram is projected onto a silicon wafer by a conventional spatial light modulator (SLM). The corresponding photo-generated carrier spatial distribution will be induced, which forms an amplitude hologram to modulate the wave front of the input THz beam. Some special intensity patterns and vortex beams are generated by using this method. This all-optical controllable STM is structure free, high resolution and broadband. It is expected to be widely used in future THz imaging and communication systems.

  17. A New View on the Space-Time Pattern of M>7 Earthquakes in the Northern Japan to Kurile Subduction Zones

    NASA Astrophysics Data System (ADS)

    Harada, T.; Satake, K.

    2012-04-01

    The northern Japan to southern Kurile trenches have been regarded as a typical subduction zone with spatially and temporally regular recurrence of great (M>8) interplate earthquakes. The source regions were grouped into six segments by Utsu (1972; 1984). The Headquarters for Earthquake Research Promotion of the Japanese government (2004) divided the southern Kurile subduction zone into four regions and evaluated future probabilities of great interplate earthquakes. Besides great interplate events, however, many large (M>7) interplate, intraslab, outer-rise and tsunami earthquakes have also occurred in this region. First, we depicted the space-time pattern of M>7 earthquakes along the northern Japan to Kuril trench, based on the relocated mainshock-aftershock distributions of all types of earthquakes occurred since 1913. We relocated the hypocenters reported in the ISC, ISS, and BCIS bulletins by using the HYPOSAT (Schweitzer, 2003) and the Modified JHD method (Hurukawa, 1995). Then, in order to examine more detail space pattern, or rupture areas, of M>7 earthquakes since 1963, we estimated coseismic slip distributions by the Kikuchi and Kanamori's (2003) teleseismic body wave inversion method. The WWSSN waveform data were used for earthquakes between 1963 and 1990, and digital teleseismic waveform data compiled by the IRIS were used for events after 1990. Mainshock hypocenters relocated by us were used as initial rupture points. As a result, we found that the more complex feature of earthquake occurrence. Each region has been ruptured by a M8-class interplate earthquake or by multiple M7-class events. Offshore Urup Is. is source region of the 1963 Urup earthquake (M 8.5). Large interplate earthquakes occurred in the eastern and western part of the 1963 source region in 1991 (M 7.6) and 1995 (M 7.9), respectively. Their aftershock areas almost re-occupied the 1963 aftershock area. The 1963, 1991, and 1995 coseismic slip distributions show that the southwestern

  18. Characterization of in vitro generated metabolites of the selective androgen receptor modulators S-22 and S-23 and in vivo comparison to post-administration canine urine specimens.

    PubMed

    Thevis, Mario; Gerace, Enrico; Thomas, Andreas; Beuck, Simon; Geyer, Hans; Schlörer, Nils; Kearbey, Jeffrey D; Dalton, James T; Schänzer, Wilhelm

    2010-01-01

    Selective androgen receptor modulators (SARMs) have great therapeutic potential in various diseases including cancer cachexia, sarcopenia, and osteoporosis, and the number of drug candidates has been growing over the last decade. The SARM drug candidates S-22 and S-23 belong to one of the most advanced groups of androgen receptor modulators and are based on an arylpropionamide-derived core structure. Due to their anabolic effects, SARMs have been prohibited in elite sports and have been a subject of sports drug testing programmes since January 2008. Consequently, the structure of analytically useful urinary metabolites should be elucidated to provide targets for sensitive and retrospective analysis. In the present study, the phase-I and -II metabolism of S-22 and S-23 was simulated using hepatic human enzymes, and resulting metabolites were characterized by means of state-of-the-art mass spectrometric approaches employing high resolution/high accuracy Orbitrap mass spectrometry. Subsequently, the newly defined target compounds including the glucuronic acid conjugates of S-22 and S-23, their corresponding monohydroxylated and bishydroxylated analogs, as well as their B-ring depleted counterparts were implemented into an existing routine doping control procedure, which was examined for its specificity for the added substances. In order to obtain proof-of-concept data for authentic urine specimens, canine urine samples collected up to 72 h after oral administration of S-22 to dogs were analyzed using the established approach outlining the capability of the presented assay to detect the glucuronide of S-22 as well as the B-ring-depleted metabolite (M3) in all samples following therapeutic (31.4 µg/kg) dosing. Finally, M3 was chemically synthesized, characterized by nuclear magnetic resonance spectroscopy and high resolution/high accuracy mass spectrometry, and chosen as primary target for future doping control analyses.

  19. A Comparative Analysis of Synthetic Quorum Sensing Modulators in Pseudomonas aeruginosa: New Insights into Mechanism, Active Efflux Susceptibility, Phenotypic Response, and Next-Generation Ligand Design

    PubMed Central

    2015-01-01

    Quorum sensing (QS) is a chemical signaling mechanism that allows bacterial populations to coordinate gene expression in response to social and environmental cues. Many bacterial pathogens use QS to initiate infection at high cell densities. Over the past two decades, chemical antagonists of QS in pathogenic bacteria have attracted substantial interest for use both as tools to further elucidate QS mechanisms and, with further development, potential anti-infective agents. Considerable recent research has been devoted to the design of small molecules capable of modulating the LasR QS receptor in the opportunistic pathogen Pseudomonas aeruginosa. These molecules hold significant promise in a range of contexts; however, as most compounds have been developed independently, comparative activity data for these compounds are scarce. Moreover, the mechanisms by which the bulk of these compounds act are largely unknown. This paucity of data has stalled the choice of an optimal chemical scaffold for further advancement. Herein, we submit the best-characterized LasR modulators to standardized cell-based reporter and QS phenotypic assays in P. aeruginosa, and we report the first comprehensive set of comparative LasR activity data for these compounds. Our experiments uncovered multiple interesting mechanistic phenomena (including a potential alternative QS-modulatory ligand binding site/partner) that provide new, and unexpected, insights into the modes by which many of these LasR ligands act. The lead compounds, data trends, and mechanistic insights reported here will significantly aid the design of new small molecule QS inhibitors and activators in P. aeruginosa, and in other bacteria, with enhanced potencies and defined modes of action. PMID:26491787

  20. Ascorbate and α-tocopherol differentially modulate reactive oxygen species generation by neutrophils in response to FcγR and TLR agonists.

    PubMed

    Chapple, Iain Lc; Matthews, John B; Wright, Helen J; Scott, Ann E; Griffiths, Helen R; Grant, Melissa M

    2013-01-01

    Periodontitis, a ubiquitous chronic inflammatory disease, is associated with reduced antioxidant defences and neutrophil hyperactivity in terms of reactive oxygen species (ROS) generation. Its phenotype is thus characterized by oxidative stress. We have determined the effect of antioxidant micronutrients ascorbate and α-tocopherol on neutrophil ROS generation. Peripheral neutrophils from periodontally-healthy individuals (n = 20) were challenged with phorbol myristate acetate, IgG-opsonised Staphylococcus aureus, Fusobacterium nucleatum or PBS in the presence and absence of micronutrients (50 µM). Total and extracellular ROS were measured by luminol and isoluminol chemiluminescence respectively. Total and extracellular unstimulated, baseline ROS generation was unaffected by α-tocopherol, but inhibited by ascorbate and a combination of both micronutrients. Fcγ-receptor (Fcγ-R)-stimulated total or extracellular ROS generation was not affected by the presence of individual micronutrients. However, the combination significantly reduced extracellular FcγR-stimulated ROS release. Neither micronutrient inhibited TLR-stimulated total ROS, but the combination caused inhibition. Ascorbate and the micronutrient combination, but not α-tocopherol, inhibited extracellular ROS release by TLR-stimulated cells. Such micronutrient effects in vivo could be beneficial in reducing collateral tissue damage in chronic inflammatory diseases, such as periodontitis, while retaining immune-mediated neutrophil function. PMID:22914919

  1. Module Configuration

    DOEpatents

    Oweis, Salah; D'Ussel, Louis; Chagnon, Guy; Zuhowski, Michael; Sack, Tim; Laucournet, Gaullume; Jackson, Edward J.

    2002-06-04

    A stand alone battery module including: (a) a mechanical configuration; (b) a thermal management configuration; (c) an electrical connection configuration; and (d) an electronics configuration. Such a module is fully interchangeable in a battery pack assembly, mechanically, from the thermal management point of view, and electrically. With the same hardware, the module can accommodate different cell sizes and, therefore, can easily have different capacities. The module structure is designed to accommodate the electronics monitoring, protection, and printed wiring assembly boards (PWAs), as well as to allow airflow through the module. A plurality of modules may easily be connected together to form a battery pack. The parts of the module are designed to facilitate their manufacture and assembly.

  2. Evolution of Hyperbolic-Secant Pulses Towards Cross-Phase Modulation Induced Optical Wave Breaking and Soliton or Soliton Trains Generation in Quintic Nonlinear Fibers

    NASA Astrophysics Data System (ADS)

    Zhong, Xian-Qiong; Zhang, Xiao-Xia; Du, Xian-Tong; Liu, Yong; Cheng, Ke

    2015-10-01

    The approximate analytical frequency chirps and the critical distances for cross-phase modulation induced optical wave breaking (OWB) of the initial hyperbolic-secant optical pulses propagating in optical fibers with quintic nonlinearity (QN) are presented. The pulse evolutions in terms of the frequency chirps, shapes and spectra are numerically calculated in the normal dispersion regime. The results reveal that, depending on different QN parameters, the traditional OWB or soliton or soliton pulse trains may occur. The approximate analytical critical distances are found to be in good agreement with the numerical ones only for the traditional OWB whereas the approximate analytical frequency chirps accords well with the numerical ones at the initial evolution stages of the pulses. Supported by the Postdoctoral Fund of China under Grant No. 2011M501402, the Key Project of Chinese Ministry of Education under Grant No. 210186, the Major Project of Natural Science Supported by the Educational Department of Sichuan Province under Grant No. 13ZA0081, the Key Project of National Natural Science Foundation of China under Grant No 61435010, and the National Natural Science Foundation of China under Grant No. 61275039

  3. Structural basis for m7G recognition and 2'-O-methyl discrimination in capped RNAs by the innate immune receptor RIG-I.

    PubMed

    Devarkar, Swapnil C; Wang, Chen; Miller, Matthew T; Ramanathan, Anand; Jiang, Fuguo; Khan, Abdul G; Patel, Smita S; Marcotrigiano, Joseph

    2016-01-19

    RNAs with 5'-triphosphate (ppp) are detected in the cytoplasm principally by the innate immune receptor Retinoic Acid Inducible Gene-I (RIG-I), whose activation triggers a Type I IFN response. It is thought that self RNAs like mRNAs are not recognized by RIG-I because 5'ppp is capped by the addition of a 7-methyl guanosine (m7G) (Cap-0) and a 2'-O-methyl (2'-OMe) group to the 5'-end nucleotide ribose (Cap-1). Here we provide structural and mechanistic basis for exact roles of capping and 2'-O-methylation in evading RIG-I recognition. Surprisingly, Cap-0 and 5'ppp double-stranded (ds) RNAs bind to RIG-I with nearly identical Kd values and activate RIG-I's ATPase and cellular signaling response to similar extents. On the other hand, Cap-0 and 5'ppp single-stranded RNAs did not bind RIG-I and are signaling inactive. Three crystal structures of RIG-I complexes with dsRNAs bearing 5'OH, 5'ppp, and Cap-0 show that RIG-I can accommodate the m7G cap in a cavity created through conformational changes in the helicase-motif IVa without perturbing the ppp interactions. In contrast, Cap-1 modifications abrogate RIG-I signaling through a mechanism involving the H830 residue, which we show is crucial for discriminating between Cap-0 and Cap-1 RNAs. Furthermore, m7G capping works synergistically with 2'-O-methylation to weaken RNA affinity by 200-fold and lower ATPase activity. Interestingly, a single H830A mutation restores both high-affinity binding and signaling activity with 2'-O-methylated dsRNAs. Our work provides new structural insights into the mechanisms of host and viral immune evasion from RIG-I, explaining the complexity of cap structures over evolution. PMID:26733676

  4. Desorption Kinetics of H2O from Cab-O-Sil-M-7D and Hi-Sil-233 Silica Particles

    SciTech Connect

    Dinh, L.; Balooch, M.; LeMay, J.D.

    2000-01-26

    Temperature programmed desorption (TPD) was performed at temperatures up to 850K on Cab-O-Sil-M-7D and Hi-Sil-233 silica particles. Physisorbed water molecules on both types of silica had activation energies in the range of 9-14.5 kcal/mol. However, the activation energies of desorption for chemisorbed water varied from {approx} 19 kcal/mol to > 59 kcal/mol for Cab-O-Sil-M-7D, and {approx} 23-37 kcal/mol for Hi-Sil-233. Our results suggest that physisorbed water can be effectively pumped away at room temperature (or preferably at 320 K) in a matter of hours. Chemisorbed water with high activation energies of desorption (>30 kcal/mol) will not escape the silica surfaces in 100 years even at 320 K, while a significant amount of the chemisorbed water with medium activation energies (19-26 kcal/mol) will leave the silica surfaces in that time span. Most of the chemisorbed water with activation energies < 30 kcal/mol can be pumped away in a matter of days in a good vacuum environment at 500 K. We had previously measured about 0.1-0.4 wt. % of water in M9787 polysiloxane formulations containing {approx} 21% Cab-O-Sil-M-7D and {approx} 4% Hi-Sil-233. Comparing present results with these formulations, we conclude that absorbed H{sub 2}O and Si-OH bonds on the silica surfaces are the major contributors to water outgassing from M97 series silicones.

  5. Development and validation of a liquid medium (M7H9C) for routine culture of Mycobacterium avium subsp. paratuberculosis to replace modified Bactec 12B medium.

    PubMed

    Whittington, Richard J; Whittington, Ann-Michele; Waldron, Anna; Begg, Douglas J; de Silva, Kumi; Purdie, Auriol C; Plain, Karren M

    2013-12-01

    Liquid culture of Mycobacterium avium subsp. paratuberculosis from clinical samples, such as feces, is the most sensitive antemortem test for the diagnosis of Johne's disease in ruminants. In Australia, New Zealand, the United States, and some other countries, the Bactec 460 system with modified Bactec 12B medium (Becton, Dickinson) has been the most commonly used liquid culture system, but it was discontinued in 2012. In this study, a new liquid culture medium, M7H9C, was developed. It consists of a Middlebrook 7H9 medium base with added Casitone, albumin, dextrose, catalase, egg yolk, mycobactin J, and a cocktail of antibiotics. We found that polyoxyethylene stearate (POES) was not essential for the cultivation of M. avium subsp. paratuberculosis in either the Bactec 12B or the M7H9C medium. The limit of detection determined using pure cultures of the C and S strains of M. avium subsp. paratuberculosis was 7 bacilli per 50 μl inoculum in the two media. The new medium was validated using 784 fecal and tissue samples from sheep and cattle, >25% of which contained viable M. avium subsp. paratuberculosis. Discrepant results for the clinical samples between the two media were mostly associated with samples that contained <10 viable bacilli per gram, but these results were relatively uncommon, and the performances of the two media were not significantly different. M7H9C medium was less than half the cost of the Bactec 12B medium and did not require regular examination during incubation, but a confirmatory IS900 PCR test had to be performed on every culture after the predetermined incubation period.

  6. Intracellular secretory leukoprotease inhibitor modulates inositol 1,4,5-triphosphate generation and exerts an anti-inflammatory effect on neutrophils of individuals with cystic fibrosis and chronic obstructive pulmonary disease.

    PubMed

    Reeves, Emer P; Banville, Nessa; Ryan, Dorothy M; O'Reilly, Niamh; Bergin, David A; Pohl, Kerstin; Molloy, Kevin; McElvaney, Oliver J; Alsaleh, Khalifah; Aljorfi, Ahmed; Kandalaft, Osama; O'Flynn, Eimear; Geraghty, Patrick; O'Neill, Shane J; McElvaney, Noel G

    2013-01-01

    Secretory leukoprotease inhibitor (SLPI) is an anti-inflammatory protein present in respiratory secretions. Whilst epithelial cell SLPI is extensively studied, neutrophil associated SLPI is poorly characterised. Neutrophil function including chemotaxis and degranulation of proteolytic enzymes involves changes in cytosolic calcium (Ca(2+)) levels which is mediated by production of inositol 1,4,5-triphosphate (IP3) in response to G-protein-coupled receptor (GPCR) stimuli. The aim of this study was to investigate the intracellular function of SLPI and the mechanism-based modulation of neutrophil function by this antiprotease. Neutrophils were isolated from healthy controls (n = 10), individuals with cystic fibrosis (CF) (n = 5) or chronic obstructive pulmonary disease (COPD) (n = 5). Recombinant human SLPI significantly inhibited fMet-Leu-Phe (fMLP) and interleukin(IL)-8 induced neutrophil chemotaxis (P < 0.05) and decreased degranulation of matrix metalloprotease-9 (MMP-9), hCAP-18, and myeloperoxidase (MPO) (P < 0.05). The mechanism of inhibition involved modulation of cytosolic IP3 production and downstream Ca(2+) flux. The described attenuation of Ca(2+) flux was overcome by inclusion of exogenous IP3 in electropermeabilized cells. Inhibition of IP3 generation and Ca(2+) flux by SLPI may represent a novel anti-inflammatory mechanism, thus strengthening the attractiveness of SLPI as a potential therapeutic molecule in inflammatory airway disease associated with excessive neutrophil influx including CF, non-CF bronchiectasis, and COPD.

  7. Analysis of carrier transport and carrier trapping in organic diodes with polyimide-6,13-Bis(triisopropylsilylethynyl)pentacene double-layer by charge modulation spectroscopy and optical second harmonic generation measurement

    SciTech Connect

    Lim, Eunju E-mail: taguchi.d.aa@m.titech.ac.jp; Taguchi, Dai E-mail: taguchi.d.aa@m.titech.ac.jp Iwamoto, Mitsumasa E-mail: taguchi.d.aa@m.titech.ac.jp

    2014-08-18

    We studied the carrier transport and carrier trapping in indium tin oxide/polyimide (PI)/6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene)/Au diodes by using charge modulation spectroscopy (CMS) and time-resolved electric field induced optical second harmonic generation (TR-EFISHG) measurements. TR-EFISHG directly probes the spatial carrier behaviors in the diodes, and CMS is useful in explaining the carrier motion with respect to energy. The results clearly indicate that the injected carriers move across TIPS-pentacene thorough the molecular energy states of TIPS-pentacene and accumulate at the PI/TIPS-pentacene interface. However, some carriers are trapped in the PI layers. These findings take into account the capacitance-voltage and current-voltage characteristics of the diodes.

  8. Concentration-modulated absorption spectroscopy.

    PubMed

    Langley, A J; Beaman, R A; Baran, J; Davies, A N; Jones, W J

    1985-07-01

    Concentration modulation is demonstrated to be a technique capable of markedly extending sensitivity limits in absorption spectroscopy. The gain generated relates in such a manner to sample transmittance that for the first reported time direct spectroscopic concentration measurements become possible. When concentration modulation is used with picosecond lasers, state lifetimes can be determined to a limit of approximately 20 psec.

  9. Input/output interface module

    NASA Technical Reports Server (NTRS)

    Ozyazici, E. M.

    1980-01-01

    Module detects level changes in any of its 16 inputs, transfers changes to its outputs, and generates interrupts when changes are detected. Up to four changes-in-state per line are stored for later retrieval by controlling computer. Using standard TTL logic, module fits 19-inch rack-mounted console.

  10. 12 May 2008 M = 7.9 Wenchuan, China, earthquake calculated to increase failure stress and seismicity rate on three major fault systems

    USGS Publications Warehouse

    Toda, S.; Lin, J.; Meghraoui, M.; Stein, R.S.

    2008-01-01

    The Wenchuan earthquake on the Longmen Shan fault zone devastated cities of Sichuan, claiming at least 69,000 lives. We calculate that the earthquake also brought the Xianshuihe, Kunlun and Min Jiang faults 150-400 km from the mainshock rupture in the eastern Tibetan Plateau 0.2-0.5 bars closer to Coulomb failure. Because some portions of these stressed faults have not ruptured in more than a century, the earthquake could trigger or hasten additional M > 7 earthquakes, potentially subjecting regions from Kangding to Daofu and Maqin to Rangtag to strong shaking. We use the calculated stress changes and the observed background seismicity to forecast the rate and distribution of damaging shocks. The earthquake probability in the region is estimated to be 57-71% for M ??? 6 shocks during the next decade, and 8-12% for M ??? 7 shocks. These are up to twice the probabilities for the decade before the Wenchuan earthquake struck. Copyright 2008 by the American Geophysical Union.

  11. Strong-motion observations of the M 7.8 Gorkha, Nepal, earthquake sequence and development of the N-shake strong-motion network

    USGS Publications Warehouse

    Dixit, Amod; Ringler, Adam; Sumy, Danielle F.; Cochran, Elizabeth S.; Hough, Susan E.; Martin, Stacey; Gibbons, Steven; Luetgert, James H.; Galetzka, John; Shrestha, Surya; Rajaure, Sudhir; McNamara, Daniel E.

    2015-01-01

    We present and describe strong-motion data observations from the 2015 M 7.8 Gorkha, Nepal, earthquake sequence collected using existing and new Quake-Catcher Network (QCN) and U.S. Geological Survey NetQuakes sensors located in the Kathmandu Valley. A comparison of QCN data with waveforms recorded by a conventional strong-motion (NetQuakes) instrument validates the QCN data. We present preliminary analysis of spectral accelerations, and peak ground acceleration and velocity for earthquakes up to M 7.3 from the QCN stations, as well as preliminary analysis of the mainshock recording from the NetQuakes station. We show that mainshock peak accelerations were lower than expected and conclude the Kathmandu Valley experienced a pervasively nonlinear response during the mainshock. Phase picks from the QCN and NetQuakes data are also used to improve aftershock locations. This study confirms the utility of QCN instruments to contribute to ground-motion investigations and aftershock response in regions where conventional instrumentation and open-access seismic data are limited. Initial pilot installations of QCN instruments in 2014 are now being expanded to create the Nepal–Shaking Hazard Assessment for Kathmandu and its Environment (N-SHAKE) network.

  12. A biomimetic mass-flow transducer utilizing all-optofluidic generation of self-digitized, pulse code-modulated optical pulse trains.

    PubMed

    Lee, Jiwon; Paek, Jungwook; Kim, Jaeyoun

    2012-10-01

    We present a new mass-flow transducer producing responses in the form of optical pulse trains that are encoded with information on the strength and position of the stimulus. We implemented the self-digitization and encoding capabilities all-optofluidically, without involving external electronics, by integrating one optical fiber cantilever with multiple polymer optical waveguides on a microfluidic platform. The transducer can also be configured to respond only to transitional stimuli. These features closely mimic the rate-coding, action potential labeling, and rapid adaptation processes observed in biological mechanoreceptors and allow multiple transducers to transmit signals over a single, shared channel. We fabricated the transducer using polymer-based soft-lithography techniques. Its characterization confirmed the stimulus strength-dependent generation of optical pulses and the feasibility of multiplexing 2(n-1) to 2(n) transducers using n waveguides. PMID:22858863

  13. Flip-Flop Digital Modulator

    NASA Technical Reports Server (NTRS)

    Eno, R. F.

    1984-01-01

    Clock switched on and off in response to data signal. Flip-flop modulator generates square-wave carrier frequency that is half clock frequency and turns carrier on and off. Final demodulator output logical inverse of data input.

  14. A Search for Coronal Emission at the Bottom of the Main-Sequence: Stars and Brown Dwarf Candidates with Spectral Types Later than M7 and the Rotation-Activity Relation

    NASA Technical Reports Server (NTRS)

    Stringfellow, Guy

    2004-01-01

    This program intended to test whether the lowest mass stars at the bottom end of the main sequence and the lower mass brown dwarfs have coronae. If they have coronae, what are the coronal characteristics and what drives them? In the classical dynamo picture, the closed magnetic loop structure is generated near the boundary of the convective envelope and the radiative core. Stars with mass below 0.30 Msun however are fully convective, and the nature of the dynamo responsible for the generation of the coronae in this regime is poorly understood. Previous results from the ROSAT mission (e.g., Fleming et al. 1993, 1995; Schmitt et al. 1995) had confirmed three very important characteristics of M-star coronae: (1) a very high percentage of all M dwarfs have coronae (of order 85% in the local 7 pc sample), (2) those M dwarfs showing high chromospheric activity, such as having the Balmer series in emission or large/numerous optical flaring, indeed exhibit the highest coronal activity, and (3) that the maximum saturation boundary in X-ray luminosity, which amounts to 0.0001-0.001 for Lx/Lbol for the dMe stars, extends down to the current detection limit, through spectral types M7. It was likely that the incompleteness noted for result (1) above was simply a detection limit problem; for more distant sources, the X-ray fainter dM stars will drop below detection thresholds before the more X-ray luminous dMe stars. The latest stars for which direct detection of the corona had been successful were of spectral type dM7 (e.g., VB8, LHS 3003). This program proposed to obtain ROSAT HRI observations for a large number of the coolest known (at that time) stars at the bottom of the main-sequence, which had spectral types of M9 or later. Three stars were approved for observations with ROSAT-HRI totaling 180 ksec. The goal was to obtain X-ray detections or low upper limits for the three approved stars.

  15. Tuned grid generation with ICEM CFD

    NASA Technical Reports Server (NTRS)

    Wulf, Armin; Akdag, Vedat

    1995-01-01

    ICEM CFD is a CAD based grid generation package that supports multiblock structured, unstructured tetrahedral and unstructured hexahedral grids. Major development efforts have been spent to extend ICEM CFD's multiblock structured and hexahedral unstructured grid generation capabilities. The modules added are: a parametric grid generation module and a semi-automatic hexahedral grid generation module. A fully automatic version of the hexahedral grid generation module for around a set of predefined objects in rectilinear enclosures has been developed. These modules will be presented and the procedures used will be described, and examples will be discussed.

  16. The C-terminal region of thermophilic tRNA (m7G46) methyltransferase (TrmB) stabilizes the dimer structure and enhances fidelity of methylation.

    PubMed

    Tomikawa, Chie; Ochi, Anna; Hori, Hiroyuki

    2008-05-15

    Transfer RNA (m(7)G46) methyltransferase catalyzes methyl-transfer from S-adenosyl-L-methionine to N(7) atom of the semi-conserved G46 base in tRNA. Aquifex aeolicus is a hyper thermophilic eubacterium that grows at close to 95 degrees C. A. aeolicus tRNA (m(7)G46) methyltransferase [TrmB] has an elongated C-terminal region as compared with mesophilic counterparts. In this study, the authors focused on the functions of this C-terminal region. Analytic gel filtration chromatography and amino acid sequencing reveled that the start point (Glu202) of the C-terminal region is often cleaved by proteases during purification steps and the C-terminal region tightly binds to another subunit even in the presence of 6M urea. Because the C-terminal region contains abundant basic amino acid residues, the authors assumed that some of these residues might be involved in tRNA binding. To address this idea, the authors prepared eight alanine substitution mutant proteins. However, measurements of initial velocities of these mutant proteins suggested that the basic amino acid residues in the C-terminal region are not involved in tRNA binding. The authors investigated effects of the deletion of the C-terminal region. Deletion mutant protein of the C-terminal region (the core protein) was precipitated by incubation at 85 degrees C, while the wild type protein was soluble at that temperature, demonstrating that the C-terminal region contributes to the protein stability at high temperatures. The core protein had a methyl-transfer activity to yeast tRNA(Phe) transcript. Furthermore, the core protein slowly methylated tRNA transcripts, which did not contain G46 base. Moreover, the modified base was identified as m(7)G by two-dimensional thin layer chromatography. Thus, the deletion of the C-terminal region causes nonspecific methylation of N(7) atom of guanine base(s) in tRNA transcripts.

  17. Structural basis for m7G recognition and 2′-O-methyl discrimination in capped RNAs by the innate immune receptor RIG-I

    PubMed Central

    Devarkar, Swapnil C.; Wang, Chen; Miller, Matthew T.; Ramanathan, Anand; Jiang, Fuguo; Khan, Abdul G.; Patel, Smita S.; Marcotrigiano, Joseph

    2016-01-01

    RNAs with 5′-triphosphate (ppp) are detected in the cytoplasm principally by the innate immune receptor Retinoic Acid Inducible Gene-I (RIG-I), whose activation triggers a Type I IFN response. It is thought that self RNAs like mRNAs are not recognized by RIG-I because 5′ppp is capped by the addition of a 7-methyl guanosine (m7G) (Cap-0) and a 2′-O-methyl (2′-OMe) group to the 5′-end nucleotide ribose (Cap-1). Here we provide structural and mechanistic basis for exact roles of capping and 2′-O-methylation in evading RIG-I recognition. Surprisingly, Cap-0 and 5′ppp double-stranded (ds) RNAs bind to RIG-I with nearly identical Kd values and activate RIG-I’s ATPase and cellular signaling response to similar extents. On the other hand, Cap-0 and 5′ppp single-stranded RNAs did not bind RIG-I and are signaling inactive. Three crystal structures of RIG-I complexes with dsRNAs bearing 5′OH, 5′ppp, and Cap-0 show that RIG-I can accommodate the m7G cap in a cavity created through conformational changes in the helicase-motif IVa without perturbing the ppp interactions. In contrast, Cap-1 modifications abrogate RIG-I signaling through a mechanism involving the H830 residue, which we show is crucial for discriminating between Cap-0 and Cap-1 RNAs. Furthermore, m7G capping works synergistically with 2′-O-methylation to weaken RNA affinity by 200-fold and lower ATPase activity. Interestingly, a single H830A mutation restores both high-affinity binding and signaling activity with 2′-O-methylated dsRNAs. Our work provides new structural insights into the mechanisms of host and viral immune evasion from RIG-I, explaining the complexity of cap structures over evolution. PMID:26733676

  18. Excitability and Burst Generation of AVPV Kisspeptin Neurons Are Regulated by the Estrous Cycle Via Multiple Conductances Modulated by Estradiol Action123

    PubMed Central

    Wang, Luhong

    2016-01-01

    Abstract The preovulatory secretory surge of gonadotropin-releasing hormone (GnRH) is crucial for fertility and is regulated by a switch of estradiol feedback action from negative to positive. GnRH neurons likely receive estradiol feedback signals via ERα-expressing afferents. Kisspeptin neurons in anteroventral periventricular nucleus (AVPV) are thought to be critical for estradiol-positive feedback induction of the GnRH surge. We examined the electrophysiological properties of GFP-identified AVPV kisspeptin neurons in brain slices from mice on the afternoon of diestrus (negative feedback) and proestrus (positive feedback, time of surge). Extracellular recordings revealed increased firing frequency and action potential bursts on proestrus versus diestrus. Whole-cell recordings were used to study the intrinsic mechanisms of bursting. Upon depolarization, AVPV kisspeptin neurons exhibited tonic firing or depolarization-induced bursts (DIB). Both tonic and DIB cells exhibited bursts induced by rebound from hyperpolarization. DIB occurred similarly on both cycle stages, but rebound bursts were observed more often on proestrus. DIB and rebound bursts were both sensitive to Ni2+, suggesting that T-type Ca2+ currents (ITs) are involved. IT current density was greater on proestrus versus diestrus. In addition to IT, persistent sodium current (INaP) facilitated rebound bursting. On diestrus, 4-aminopyridine-sensitive potassium currents contributed to reduced rebound bursts in both tonic and DIB cells. Manipulation of specific sex steroids suggests that estradiol induces the changes that enhance AVPV kisspeptin neuron excitability on proestrus. These observations indicate cycle-driven changes in circulating estradiol increased overall action potential generation and burst firing in AVPV kisspeptin neurons on proestrus versus diestrus by regulating multiple intrinsic currents. PMID:27280155

  19. Mechanisms involved in the modulation of astroglial resistance to oxidative stress induced by activated microglia: antioxidative systems, peroxide elimination, radical generation, lipid peroxidation.

    PubMed

    Röhl, Claudia; Armbrust, Elisabeth; Herbst, Eva; Jess, Anne; Gülden, Michael; Maser, Edmund; Rimbach, Gerald; Bösch-Saadatmandi, Christine

    2010-05-01

    Microglia and astrocytes are the cellular key players in many neurological disorders associated with oxidative stress and neuroinflammation. Previously, we have shown that microglia activated by lipopolysaccharides (LPS) induce the expression of antioxidative enzymes in astrocytes and render them more resistant to hydrogen peroxide (H2O2). In this study, we examined the mechanisms involved with respect to the cellular action of different peroxides, the ability to detoxify peroxides, and the status of further antioxidative systems. Astrocytes were treated for 3 days with medium conditioned by purified quiescent (microglia-conditioned medium, MCM[-]) or LPS-activated (MCM[+]) microglia. MCM[+] reduced the cytotoxicity of the organic cumene hydroperoxide in addition to that of H2O2. Increased peroxide resistance was not accompanied by an improved ability of astrocytes to remove H2O2 or an increased expression/activity of peroxide eliminating antioxidative enzymes. Neither peroxide-induced radical generation nor lipid peroxidation were selectively affected in MCM[+] treated astrocytes. The glutathione content of peroxide resistant astrocytes, however, was increased and superoxide dismutase and heme oxygenase were found to be upregulated. These changes are likely to contribute to the higher peroxide resistance of MCM[+] treated astrocytes by improving their ability to detoxify reactive oxygen radicals and oxidation products. For C6 astroglioma cells a protective effect of microglia-derived factors could not be observed, underlining the difference of primary cells and cell lines concerning their mechanisms of oxidative stress resistance. Our results indicate the importance of microglial-astroglial cell interactions during neuroinflammatory processes.

  20. Photovoltaic module reliability workshop

    SciTech Connect

    Mrig, L.

    1990-01-01

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  1. Solid state pulsed power generator

    SciTech Connect

    Tao, Fengfeng; Saddoughi, Seyed Gholamali; Herbon, John Thomas

    2014-02-11

    A power generator includes one or more full bridge inverter modules coupled to a semiconductor opening switch (SOS) through an inductive resonant branch. Each module includes a plurality of switches that are switched in a fashion causing the one or more full bridge inverter modules to drive the semiconductor opening switch SOS through the resonant circuit to generate pulses to a load connected in parallel with the SOS.

  2. Dietary methoxychlor exposure modulates splenic natural killer cell activity, antibody-forming cell response and phenotypic marker expression in F0 and F1 generations of Sprague Dawley rats.

    PubMed

    White, K L; Germolec, D R; Booker, C D; Hernendez, D M; McCay, J A; Delclos, K B; Newbold, R R; Weis, C; Guo, T L

    2005-02-14

    Methoxychlor, a chlorinated hydrocarbon pesticide, is a persistent environmental contaminant that has been identified in human reproductive tissues. Methoxychlor has been shown to be estrogenic in both in vivo and in vitro studies. As an endocrine disrupter, it may have the potential to adversely affect endocrine, reproductive, and immune systems in animals. The present study evaluated methoxychlor's immunotoxic potential in F0 (dams) and F1 generations of Sprague Dawley rats exposed to an isoflavone-free diet containing methoxychlor at concentrations of 10, 100, and 1000 ppm. In dams, exposure to methoxychlor from gestation day 7 to postpartum day 51 (65 days total exposure) produced a significant increase in the NK activity (1000 ppm) and the percentages of T cells (1000 ppm), helper T cells (1000 ppm) and macrophages (100 and 1000 ppm). In contrast, a decrease in the numbers of splenocytes and B cells was observed at the 100 and 1000 ppm concentrations. In F1 males, exposure to methoxychlor gestationally, lactationally and through feed from postnatal day 22-64 (78 days total exposure) produced an increase in the spleen IgM antibody-forming cell response to sheep red blood cells (100 and 1000 ppm) and the activity of NK cells (1000 ppm). However, there was a decrease in the terminal body weight (1000 ppm), spleen weight (1000 ppm), thymus weight (100 and 1000 ppm), and the numbers of splenocytes (1000 ppm), B cells (100 and 1000 ppm), cytotoxic T cells (1000 ppm) and NK cells (100 and 1000 ppm). In F1 females, exposure to methoxychlor produced a decrease in the terminal body weight (1000 ppm) and the percentages of cytotoxic T cells (10, 100 and 1000 ppm). These results demonstrate that developmental and adult dietary exposure to methoxychlor modulates immune responses in Sprague Dawley rats. Immunological changes were more pronounced in the F1 generation male rats that were exposed during gestation and postpartum, when compared to the F0 and F1 generation

  3. Measuring PV module delamination

    SciTech Connect

    Murphy, E.B.

    1980-09-22

    Delamination of the encapsulating pottant from both substrate and silicon cells in solar photovoltaic modules has been a common occurrence. While the extent of delamination is in some cases minor, there are other cases where appreciably large areas have been affected. At this time, most delaminated areas do not appear to cause electrical degradation of modules; however, keeping track of delamination growth and rate of growth is important and has been difficult. More accurate measurement of delamination has been achieved by using an acoustic digitizer to record the pattern of delamination. With the aid of a computer, software can be generated that shows the exact areas of delamination. By periodic measrement of those types of modules prone to delamination, growth rates can be documented.

  4. Printed Module Interconnects

    SciTech Connect

    Stockert, Talysa R.; Fields, Jeremy D.; Pach, Gregory F.; Mauger, Scott A.; van Hest, Maikel F. A. M.

    2015-06-14

    Monolithic interconnects in photovoltaic modules connect adjacent cells in series, and are typically formed sequentially involving multiple deposition and scribing steps. Interconnect widths of 500 um every 10 mm result in 5% dead area, which does not contribute to power generation in an interconnected solar panel. This work expands on previous work that introduced an alternative interconnection method capable of producing interconnect widths less than 100 um. The interconnect is added to the module in a single step after deposition of the photovoltaic stack, eliminating the need for scribe alignment. This alternative method can be used for all types of thin film photovoltaic modules. Voltage addition with copper-indium-gallium-diselenide (CIGS) solar cells using a 2-scribe printed interconnect approach is demonstrated. Additionally, interconnect widths of 250 um are shown.

  5. Modulator-free quadrature amplitude modulation signal synthesis

    PubMed Central

    Liu, Zhixin; Kakande, Joseph; Kelly, Brian; O’Carroll, John; Phelan, Richard; Richardson, David J.; Slavík, Radan

    2014-01-01

    The ability to generate high-speed on–off-keyed telecommunication signals by directly modulating a semiconductor laser’s drive current was one of the most exciting prospective applications of the nascent field of laser technology throughout the 1960s. Three decades of progress led to the commercialization of 2.5 Gbit s−1-per-channel submarine fibre optic systems that drove the growth of the internet as a global phenomenon. However, the detrimental frequency chirp associated with direct modulation forced industry to use external electro-optic modulators to deliver the next generation of on–off-keyed 10 Gbit s−1 systems and is absolutely prohibitive for today’s (>)100 Gbit s−1 coherent systems, which use complex modulation formats (for example, quadrature amplitude modulation). Here we use optical injection locking of directly modulated semiconductor lasers to generate complex modulation format signals showing distinct advantages over current and other currently researched solutions. PMID:25523757

  6. Modulator-free quadrature amplitude modulation signal synthesis

    NASA Astrophysics Data System (ADS)

    Liu, Zhixin; Kakande, Joseph; Kelly, Brian; O'Carroll, John; Phelan, Richard; Richardson, David J.; Slavík, Radan

    2014-12-01

    The ability to generate high-speed on-off-keyed telecommunication signals by directly modulating a semiconductor laser’s drive current was one of the most exciting prospective applications of the nascent field of laser technology throughout the 1960s. Three decades of progress led to the commercialization of 2.5 Gbit s-1-per-channel submarine fibre optic systems that drove the growth of the internet as a global phenomenon. However, the detrimental frequency chirp associated with direct modulation forced industry to use external electro-optic modulators to deliver the next generation of on-off-keyed 10 Gbit s-1 systems and is absolutely prohibitive for today’s (>)100 Gbit s-1 coherent systems, which use complex modulation formats (for example, quadrature amplitude modulation). Here we use optical injection locking of directly modulated semiconductor lasers to generate complex modulation format signals showing distinct advantages over current and other currently researched solutions.

  7. Frequency-modulated continuous-wave lidar using I/Q modulator for simplified heterodyne detection.

    PubMed

    Gao, S; Hui, R

    2012-06-01

    A frequency-modulated continuous-wave (FMCW) lidar is demonstrated with heterodyne detection. The lidar transmitter utilizes an electro-optic I/Q modulator for the first time to generate carrier-suppressed and frequency-shifted FM modulation. This eliminates the need for an acousto-optic frequency shifter commonly used in heterodyne lidar transmitters. It also allows the use of a much wider modulation bandwidth to improve the range resolution. The capability of complex optical field modulation of the I/Q modulator provides an additional degree of freedom compared with an intensity modulator, which will benefit future lidar applications. PMID:22660108

  8. Bunch identification module

    SciTech Connect

    Fox, J.D.

    1981-01-01

    This module provides bunch identification and timing signals for the PEP Interaction areas. Timing information is referenced to the PEP master oscillator, and adjusted in phase as a function of region. Identification signals are generated in a manner that allows observers in all interaction regions to agree on an unambiguous bunch identity. The module provides bunch identification signals via NIM level logic, upon CAMAC command, and through LED indicators. A front panel ''region select'' switch allows the same module to be used in all regions. The module has two modes of operation: a bunch identification mode and a calibration mode. In the identification mode, signals indicate which of the three bunches of electrons and positrons are interacting, and timing information about beam crossing is provided. The calibration mode is provided to assist experimenters making time of flight measurements. In the calibration mode, three distinct gating signals are referenced to a selected bunch, allowing three timing systems to be calibrated against a common standard. Physically, the bunch identifier is constructed as a single width CAMAC module. 2 figs., 1 tab.

  9. Real-Time Science on Social Media: The Example of Twitter in the Minutes, Hours, Days after the 2015 M7.8 Nepal Earthquake

    NASA Astrophysics Data System (ADS)

    Lomax, A.; Bossu, R.; Mazet-Roux, G.

    2015-12-01

    Scientific information on disasters such as earthquakes typically comes firstly from official organizations, news reports and interviews with experts, and later from scientific presentations and peer-reviewed articles. With the advent of the Internet and social media, this information is available in real-time from automated systems and within a dynamic, collaborative interaction between scientific experts, responders and the public. After the 2015 M7.8 Nepal earthquake, Twitter Tweets from earth scientists* included information, analysis, commentary and discussion on earthquake parameters (location, size, mechanism, rupture extent, high-frequency radiation, …), earthquake effects (distribution of felt shaking and damage, triggered seismicity, landslides, …), earthquake rumors (e.g. the imminence of a larger event) and other earthquake information and observations (aftershock forecasts, statistics and maps, source and regional tectonics, seismograms, GPS, InSAR, photos/videos, …).In the future (while taking into account security, false or erroneous information and identity verification), collaborative, real-time science on social media after a disaster will give earlier and better scientific understanding and dissemination of public information, and enable improved emergency response and disaster management.* A sample of scientific Tweets after the 2015 Nepal earthquake: In the first minutes: "mb5.9 Mwp7.4 earthquake Nepal 2015.04.25-06:11:25UTC", "Major earthquake shakes Nepal 8 min ago", "Epicenter between Pokhara and Kathmandu", "Major earthquake shakes Nepal 18 min ago. Effects derived from witnesses' reports". In the first hour: "shallow thrust faulting to North under Himalayas", "a very large and shallow event ... Mw7.6-7.7", "aftershocks extend east and south of Kathmandu, so likely ruptured beneath city", "Valley-blocking landslides must be a very real worry". In the first day: "M7.8 earthquake in Nepal 2hr ago: destructive in Kathmandu Valley and

  10. N7-Methylguanine at position 46 (m7G46) in tRNA from Thermus thermophilus is required for cell viability at high temperatures through a tRNA modification network

    PubMed Central

    Tomikawa, Chie; Yokogawa, Takashi; Kanai, Tamotsu; Hori, Hiroyuki

    2010-01-01

    N7-methylguanine at position 46 (m7G46) in tRNA is produced by tRNA (m7G46) methyltransferase (TrmB). To clarify the role of this modification, we made a trmB gene disruptant (ΔtrmB) of Thermus thermophilus, an extreme thermophilic eubacterium. The absence of TrmB activity in cell extract from the ΔtrmB strain and the lack of the m7G46 modification in tRNAPhe were confirmed by enzyme assay, nucleoside analysis and RNA sequencing. When the ΔtrmB strain was cultured at high temperatures, several modified nucleotides in tRNA were hypo-modified in addition to the lack of the m7G46 modification. Assays with tRNA modification enzymes revealed hypo-modifications of Gm18 and m1G37, suggesting that the m7G46 positively affects their formations. Although the lack of the m7G46 modification and the hypo-modifications do not affect the Phe charging activity of tRNAPhe, they cause a decrease in melting temperature of class I tRNA and degradation of tRNAPhe and tRNAIle. 35S-Met incorporation into proteins revealed that protein synthesis in ΔtrmB cells is depressed above 70°C. At 80°C, the ΔtrmB strain exhibits a severe growth defect. Thus, the m7G46 modification is required for cell viability at high temperatures via a tRNA modification network, in which the m7G46 modification supports introduction of other modifications. PMID:19934251

  11. N7-Methylguanine at position 46 (m7G46) in tRNA from Thermus thermophilus is required for cell viability at high temperatures through a tRNA modification network.

    PubMed

    Tomikawa, Chie; Yokogawa, Takashi; Kanai, Tamotsu; Hori, Hiroyuki

    2010-01-01

    N(7)-methylguanine at position 46 (m(7)G46) in tRNA is produced by tRNA (m(7)G46) methyltransferase (TrmB). To clarify the role of this modification, we made a trmB gene disruptant (DeltatrmB) of Thermus thermophilus, an extreme thermophilic eubacterium. The absence of TrmB activity in cell extract from the DeltatrmB strain and the lack of the m(7)G46 modification in tRNA(Phe) were confirmed by enzyme assay, nucleoside analysis and RNA sequencing. When the DeltatrmB strain was cultured at high temperatures, several modified nucleotides in tRNA were hypo-modified in addition to the lack of the m(7)G46 modification. Assays with tRNA modification enzymes revealed hypo-modifications of Gm18 and m(1)G37, suggesting that the m(7)G46 positively affects their formations. Although the lack of the m(7)G46 modification and the hypo-modifications do not affect the Phe charging activity of tRNA(Phe), they cause a decrease in melting temperature of class I tRNA and degradation of tRNA(Phe) and tRNA(Ile). (35)S-Met incorporation into proteins revealed that protein synthesis in DeltatrmB cells is depressed above 70 degrees C. At 80 degrees C, the DeltatrmB strain exhibits a severe growth defect. Thus, the m(7)G46 modification is required for cell viability at high temperatures via a tRNA modification network, in which the m(7)G46 modification supports introduction of other modifications.

  12. Electronic modulation of biochemical signal generation

    NASA Astrophysics Data System (ADS)

    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.

  13. Electronic modulation of biochemical signal generation.

    PubMed

    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.

  14. Modular Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Mason, Lee S.; Schifer, Nicholas A.

    2016-01-01

    High-efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRGs) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high-specific-power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTGs). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and the Department of Energy (DOE) called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered, which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provided about 50 to 450 W of direct current (DC) to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator, which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific

  15. Rapid Damage Mapping for the 2015 M7.8 Gorkha Earthquake using Synthetic Aperture Radar Data from COSMO-SkyMed and ALOS-2 Satellites

    NASA Astrophysics Data System (ADS)

    Yun, S. H.; Hudnut, K. W.; Owen, S. E.; Webb, F.; Simons, M.; Macdonald, A.; Sacco, P.; Gurrola, E. M.; Manipon, G.; Liang, C.; Fielding, E. J.; Milillo, P.; Hua, H.; Coletta, A.

    2015-12-01

    The April 25, 2015 M7.8 Gorkha earthquake caused more than 8,000 fatalities and widespread building damage in central Nepal. Four days after the earthquake, the Italian Space Agency's (ASI's) COSMO-SkyMed Synthetic Aperture Radar (SAR) satellite acquired data over Kathmandu area. Nine days after the earthquake, the Japan Aerospace Exploration Agency's (JAXA's) ALOS-2 SAR satellite covered larger area. Using these radar observations, we rapidly produced damage proxy maps derived from temporal changes in Interferometric SAR (InSAR) coherence. These maps were qualitatively validated through comparison with independent damage analyses by National Geospatial-Intelligence Agency (NGA) and the UNITAR's (United Nations Institute for Training and Research's) Operational Satellite Applications Programme (UNOSAT), and based on our own visual inspection of DigitalGlobe's WorldView optical pre- vs. post-event imagery. Our maps were quickly released to responding agencies and the public, and used for damage assessment, determining inspection/imaging priorities, and reconnaissance fieldwork.

  16. Cloning, expression and characterization of a novel cold-active and organic solvent-tolerant esterase from Monascus ruber M7.

    PubMed

    Guo, Hailun; Zhang, Yan; Shao, Yanchun; Chen, Wanping; Chen, Fusheng; Li, Mu

    2016-07-01

    Cold active esterases are a class of important biocatalysts that exhibit high activity at low temperatures. In this study, a search for putative cold-active esterase encoding genes from Monascus ruber M7 was performed. A cold-active esterase, named Lip10, was isolated, cloned, purified, and characterized. Amino acid sequence analysis reveals that Lip10 contained a conserved sequence motif Gly(173)-Xaa-Ser(175)-Xaa-Gly(177) that is also present in the majority of esterases and lipases. Phylogenetic analysis indicated that Lip10 was a novel microbial esterase. The lip10 gene was cloned and heterologously expressed in Escherichia coli BL21(DE3), resulting in the expression of an active and soluble protein that constituted 40 % of the total cell protein content. Lip10 maintained almost 50 % of its maximal activity at 4-10 °C, with optimal activity at 40 °C. Furthermore, Lip10 retained 184-216 % of its original activity, after incubation in 50 % (v/v) hydrophobic organic solvents for 24 h. The enzyme also exhibited high activity under alkaline conditions and good tolerance to metal ions in the reaction mixture. These results indicate that Lip10 may have potential uses in chemical synthesis and food processing industrial applications as an esterase. PMID:27209523

  17. Effect of multiple short highly energetic X-ray pulses on the synthesis of endoglucanase by a mutant strain of Trichoderma reesei-M7

    PubMed Central

    Gemishev, Orlin; Zapryanov, Stanislav; Blagoev, Alexander; Markova, Maya; Savov, Valentin

    2014-01-01

    Bioconversion of cellulose-containing substrate to glucose represents an important area of modern biotechnology. Enzymes for the degradation of the polysaccharide part of biomass have been produced, mostly by fungi belonging to genus Trichoderma. Studies were carried out with the mutant strain Trichoderma reesei-M7, a cellulase producer. Spores of the enzyme producer were irradiated with different doses of characteristic X-ray radiation from metallic tungsten (mainly the W Kα1 and Kα2 lines) with a high dose rate. The latter is a specific property of the dense plasma focus (DPF) device, which has pulsed operation and thus gives short and highly energetic pulses of multiple types of rays and particles. In this case, we focused our study on the influence of hard X-rays. The doses of X-rays absorbed by the spores varied in the range of approximately 5–11,000 mSv measured with thermoluminescent dosimeters (TLD). The influence of the applied doses in combination with exceptionally high dose rates (in the order of tens of millisieverts per microsecond) on the activity of the produced endoglucanase, amount of biomass and extra-cellular protein, was studied in batch cultivation conditions. In the dose range of 200–1200 mSv, some enhancement of endoglucanase activity was obtained: around 18%–32%, despite the drop of the biomass amount, compared with the untreated material. PMID:26019569

  18. Case study of a magnetic transient in NOAA 11429 observed by SDO/HMI during the M7.9 flare on 2012 march 13

    SciTech Connect

    Harker, Brian J.; Pevtsov, Alexei A. E-mail: apevtsov@nso.edu

    2013-12-01

    NOAA 11429 was the source of an M7.9 X-ray flare at the western solar limb (N18° W63°) on 2012 March 13 at 17:12 UT. Observations of the line-of-sight magnetic flux and the Stokes I and V profiles from which it is derived were carried out by the Solar Dynamics Observatory Helioseismic and Magnetic Imager (SDO/HMI) with a 45 s cadence over the full disk, at a spatial sampling of 0.''5. During flare onset, a transient patch of negative flux can be observed in SDO/HMI magnetograms to rapidly appear within the positive polarity penumbra of NOAA 11429. We present here a detailed study of this magnetic transient and offer interpretations as to whether this highly debated phenomenon represents a 'real' change in the structure of the magnetic field at the site of the flare, or is instead a product of instrumental/algorithmic artifacts related to particular SDO/HMI data reduction techniques.

  19. Implications for stress changes along the Motagua fault and other nearby faults using GPS and seismic constraints on the M=7.3 2009 Swan Islands earthquake

    NASA Astrophysics Data System (ADS)

    Graham, S. E.; Rodriguez, M.; Rogers, R. D.; Strauch, W.; Hernandez, D.; Demets, C.

    2010-12-01

    The May 28, 2009 M=7.3 Swan Islands earthquake off the north coast of Honduras caused significant damage in the northern part of the country, including seven deaths. This event, the largest in the region for several decades, ruptured the offshore continuation of the Motagua-Polochic fault system, whose 1976 earthquake (located several hundred kilometers to the southwest of the 2009 epicenter) caused more than 23,000 deaths in Central America and left homeless 20% of Guatemala’s population. We use elastic half-space modeling of coseismic offsets measured at 39 GPS stations in Honduras, El Salvador, and Guatemala to better understand the slip source of the recent Swan Islands earthquake. Measured offsets range from .32 meters at a campaign site near the Motagua fault in northern Honduras to 4 millimeters at five continuous sites in El Salvador. Coulomb stress calculations based on the estimated distribution of coseismic slip will be presented and compared to earthquake focal mechanisms and aftershock locations determined from a portable seismic network that was installed in northern Honduras after the main shock. Implications of the Swan Islands rupture for the seismically hazardous Motagua-Polochic fault system will be described.

  20. GPS and seismic constraints on the M = 7.3 2009 Swan Islands earthquake: implications for stress changes along the Motagua fault and other nearby faults

    NASA Astrophysics Data System (ADS)

    Graham, Shannon E.; DeMets, Charles; DeShon, Heather R.; Rogers, Robert; Maradiaga, Manuel Rodriguez; Strauch, Wilfried; Wiese, Klaus; Hernandez, Douglas

    2012-09-01

    We use measurements at 35 GPS stations in northern Central America and 25 seismometers at teleseismic distances to estimate the distribution of slip, source time function and Coulomb stress changes of the Mw = 7.3 2009 May 28, Swan Islands fault earthquake. This event, the largest in the region for several decades, ruptured the offshore continuation of the seismically hazardous Motagua fault of Guatemala, the site of the destructive Ms = 7.5 earthquake in 1976. Measured GPS offsets range from 308 millimetres at a campaign site in northern Honduras to 6 millimetres at five continuous sites in El Salvador. Separate inversions of geodetic and seismic data both indicate that up to ˜1 m of coseismic slip occurred along a ˜250-km-long rupture zone between the island of Roatan and the eastern limit of the 1976 M = 7.5 Motagua fault earthquake in Guatemala. Evidence for slip ˜250 km west of the epicentre is corroborated independently by aftershocks recorded by a local seismic network and by the high concentration of damage to structures in areas of northern Honduras adjacent to the western limit of the rupture zone. Coulomb stresses determined from the coseismic slip distribution resolve a maximum of 1 bar of stress transferred to the seismically hazardous Motagua fault and further indicate unclamping of normal faults along the northern shore of Honduras, where two M > 5 normal-faulting earthquakes and numerous small earthquakes were triggered by the main shock.

  1. The core domain of Aquifex aeolicus tRNA (m7G46) methyltransferase has the methyl-transfer activity to tRNA.

    PubMed

    Tomikawa, Chie; Hori, Hiroyuki

    2006-01-01

    Transfer RNA (m(7)G46) methyltransferase [TrmB] catalyses the transfer of methyl groups from S-adenosyl-L-methionine to the N(7)-atom of guanine at position 46 in tRNA. TrmB proteins from thermophilic bacteria such as Aquifex aeolicus have a long C-terminal region as compared to those from mesophilic bacteria. Further, N-terminal region observed in TrmB proteins from mesophiles is missing in A. aeolicus TrmB. Therefore, we considered that this distinct C-terminal region in A. aeolicus TrmB might compensate the N-terminal region in mesophile TrmB and function as a part of tRNA binding site. To confirm this idea, we deleted the C-terminal region by introduction of the stop codon at position 202. To our surprise, methyl-transfer assay using yeast tRNA(Phe) transcript clearly showed that the resultant mutant protein (Glu202Stop) had an enzymatic activity. Thus, the core domain of the A. aeolicus TrmB has a methyl-transfer activity.

  2. Hetero subunit interaction and RNA recognition of yeast tRNA (m7G46) methyltransferase synthesized in a wheat germ cell-free translation system.

    PubMed

    Muneyoshi, Yuki; Matsumoto, Keisuke; Tomikawa, Chie; Toyooka, Takashi; Ochi, Anna; Masaoka, Takashi; Endo, Yaeta; Hori, Hiroyuki

    2007-01-01

    Yeast tRNA (m(7)G46) methyltransferase contains two protein subunits (Trm8 and Trm82). The enzyme catalyzes a methyl-transfer from S-adenosyl-L-methionine to the N(7) atom of guanine at position 46 in tRNA. We deviced synthesis of active Trm8-Trm82 heterodimer in a wheat germ cell-free translation system. When Trm8 or Trm82 mRNA were used for a synthesis, Trm8 or Trm82 protein could be synthesized. Upon mixing the synthesized Trm8 and Trm82 proteins, no active Trm8-Trm82 heterodimer was produced. Active Trm8-Trm82 heterodimer was only synthesized under conditions, in which both Trm8 and Trm82 mRNAs were co-translated. To address the RNA recognition mechanism of the Trm8-Trm82 complex, we investigated methyl acceptance activities of eight truncated yeast tRNA(Phe) transcripts. In this meeting, we demonstrate that yeast Trm8-Trm82 has stricter recognition requirements for the tRNA molecule as compared to the bacterial enzyme, TrmB.

  3. Earthquake Performance of Structures in the Philippines: A Post-event Assessment of the M7.2 October 2013 Bohol Earthquake

    NASA Astrophysics Data System (ADS)

    Naguit, M.; Cummins, P. R.; Bautista, B.; Edwards, M.; Ryu, H.; Jakab, M.

    2015-12-01

    A M7.2 inland earthquake occurred in Bohol, Philippines on the 15th of October 2013, associated with rupture along a newly-discovered thrust fault called the North Bohol Fault. While secondary hazards including lateral spreading, landslides, sinkholes, liquefaction, coastal uplift and subsidence have been observed, the impact was dominated by strong ground shaking that killed about 230 people and damaged over 70,000 buildings. Because of the extensive damage and the wide spread of intensities inferred to have shaken the island, the Bohol earthquake presents an important opportunity to improve knowledge of building fragility for the Philippines and similar countries. To this end we undertook a statistical building survey of over 18,000 damaged and undamaged structures located in urban and rural settings and at various inferred ground motion intensity levels. Building typology developed by structural engineers in the Philippines has been considered in classifying the structures based on structural materials and era of construction. The vast majority of the buildings are residential houses with wall types made of wooden materials, concrete hollow blocks or confined masonry. Tailored to assess the vulnerability of structures to earthquake loadings, this post-event analysis aims to validate and constrain the building fragility curves for seismic risk assessment. This can lead to more robust impact forecasts and higher priorities on seismic regulations and construction practices, applicable not only in Bohol but in other areas in the Philippines as well.

  4. PLASMOID EJECTIONS AND LOOP CONTRACTIONS IN AN ERUPTIVE M7.7 SOLAR FLARE: EVIDENCE OF PARTICLE ACCELERATION AND HEATING IN MAGNETIC RECONNECTION OUTFLOWS

    SciTech Connect

    Liu Wei; Chen Qingrong; Petrosian, Vahe

    2013-04-20

    Where particle acceleration and plasma heating take place in relation to magnetic reconnection is a fundamental question for solar flares. We report analysis of an M7.7 flare on 2012 July 19 observed by SDO/AIA and RHESSI. Bi-directional outflows in forms of plasmoid ejections and contracting cusp-shaped loops originate between an erupting flux rope and underlying flare loops at speeds of typically 200-300 km s{sup -1} up to 1050 km s{sup -1}. These outflows are associated with spatially separated double coronal X-ray sources with centroid separation decreasing with energy. The highest temperature is located near the nonthermal X-ray loop-top source well below the original heights of contracting cusps near the inferred reconnection site. These observations suggest that the primary loci of particle acceleration and plasma heating are in the reconnection outflow regions, rather than the reconnection site itself. In addition, there is an initial ascent of the X-ray and EUV loop-top source prior to its recently recognized descent, which we ascribe to the interplay among multiple processes including the upward development of reconnection and the downward contractions of reconnected loops. The impulsive phase onset is delayed by 10 minutes from the start of the descent, but coincides with the rapid speed increases of the upward plasmoids, the individual loop shrinkages, and the overall loop-top descent, suggestive of an intimate relation of the energy release rate and reconnection outflow speed.

  5. Strong ground motion synthesis for a M=7.2 earthquake in the Gulf of Corinth, Greece using Empirical Green`s functions

    SciTech Connect

    Hutchings, L.; Stavrakakis, G.N.; Ioannidou, E.; Wu, F.T.; Jarpe, S.; Kasameyer, P.

    1998-01-01

    We synthesize strong ground motion at three sites from a M=7.2 earthquake along the MW-trending Gulf of Cornith seismic zone. We model rupture along an 80 segment of the zone. The entire length of the fault, if activated at one time, can lead to an event comparable to that of the 1995 Kobe earthquake. With the improved digital data now routinely available, it becomes possible to use recordings of small earthquakes as empirical Green`s functions to synthesize potential ground motion for future large earthquakes. We developed a suite of 100 rupture scenarios for the earthquake and computed the commensurate strong ground motion time histories. We synthesized strong ground motion with physics-based solutions of earthquake rupture and applied physical bounds on rupture parameters. The synthesized ground motions obtained are source and site specific. By having a suite of rupture scenarios of hazardous earthquakes for a fixed magnitude and identifying the hazard to a site from the statistical distribution of engineering parameters, we have introduced a probabilistic component to the deterministic hazard calculation. The time histories suggested for engineering design are the ones that most closely match either the average or one standard deviation absolute accelerations response values.

  6. Geophysical investigation of the Denali fault and Alaska Range orogen within the aftershock zone of the October-November 2002, M = 7.9 Denali fault earthquake

    USGS Publications Warehouse

    Fisher, M.A.; Nokleberg, W.J.; Ratchkovski, N.A.; Pellerin, L.; Glen, J.M.; Brocher, T.M.; Booker, J.

    2004-01-01

    The aftershock zone of the 3 November 2002, M = 7.9 earthquake that ruptured along the right-slip Denali fault in south-central Alaska has been investigated by using gravity and magnetic, magnetotelluric, and deep-crustal, seismic reflection data as well as outcrop geology and earthquake seismology. Strong seismic reflections from within the Alaska Range orogen north of the Denali fault dip as steeply as 25°N and extend to depths as great as 20 km. These reflections outline a relict crustal architecture that in the past 20 yr has produced little seismicity. The Denali fault is nonreflective, probably because this fault dips steeply to vertical. The most intriguing finding from geophysical data is that earthquake aftershocks occurred above a rock body, with low electrical resistivity (>10 Ω·m), that is at depths below ∼10 km. Aftershocks of the Denali fault earthquake have mainly occurred shallower than 10 km. A high geothermal gradient may cause the shallow seismicity. Another possibility is that the low resistivity results from fluids, which could have played a role in locating the aftershock zone by reducing rock friction within the middle and lower crust.

  7. Vertical Crustal Stability in 23 Years Since the 1992 Cape Mendocino M 7.1 Earthquake: Benchmark Survey Results, Interpretations and Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Vermeer, J.; Crawford, B.; Hemphill-Haley, M. A.

    2015-12-01

    In 1992, a M 7.1 earthquake occurred near Petrolia, CA within the area of the Mendocino triple junction and the southern terminus of the Cascadia subduction zone (CSZ). This earthquake resulted in ~1.4 m of coastal uplift, accompanied by inland subsidence. The focal mechanism of the earthquake indicated motion along a low-angle, east-dipping thrust plane, consistent with the subduction zone interface or a subsidiary fault. If the earthquake occurred on the megathrust itself, we might expect that high strain rates resulting from Gorda/North American plate convergence would cause measurable vertical interseismic deformation in the 23 years since the event. Along other subduction zones with historic ruptures, large amounts of deformation had occurred within 10-50 years after the mainshock, resulting in crustal recovery in a direction opposite that of the coseismic deformation. However, a subsidiary fault would not accumulate strain as quickly, thus little to no vertical deformation should be observed after just 23 years. Using high resolution static GPS relocation of benchmarks and comparing these positions to the 1992 leveling elevations, we have found that there has been little to no vertical deformation since the leveling in 1992. These results indicate that the 1992 event was likely not a subduction zone rupture but rather occurred along a low strain rate subsidiary fault.

  8. Thermionic modules

    DOEpatents

    King, Donald B.; Sadwick, Laurence P.; Wernsman, Bernard R.

    2002-06-18

    Modules of assembled microminiature thermionic converters (MTCs) having high energy-conversion efficiencies and variable operating temperatures manufactured using MEMS manufacturing techniques including chemical vapor deposition. The MTCs incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. The MTCs also exhibit maximum efficiencies of just under 30%, and thousands of the devices and modules can be fabricated at modest costs.

  9. Modular Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Mason, Lee S.; Schifer, Nicholas A.

    2015-01-01

    High efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRG) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high specific power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTG). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and DOE called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provide about 50 to 450 watts DC to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific power may be slightly lower than the ASRG and

  10. Modular Isotopic Thermoelectric Generator

    SciTech Connect

    Schock, Alfred

    1981-04-03

    Advanced RTG concepts utilizing improved thermoelectric materials and converter concepts are under study at Fairchild for DOE. The design described here is based on DOE's newly developed radioisotope heat source, and on an improved silicon-germanium material and a multicouple converter module under development at Syncal. Fairchild's assignment was to combine the above into an attractive power system for use in space, and to assess the specific power and other attributes of that design. The resultant design is highly modular, consisting of standard RTG slices, each producing ~24 watts at the desired output voltage of 28 volt. Thus, the design could be adapted to various space missions over a wide range of power levels, with little or no redesign. Each RTG slice consists of a 250-watt heat source module, eight multicouple thermoelectric modules, and standard sections of insulator, housing, radiator fins, and electrical circuit. The design makes it possible to check each thermoelectric module for electrical performance, thermal contact, leaktightness, and performance stability, after the generator is fully assembled; and to replace any deficient modules without disassembling the generator or perturbing the others. The RTG end sections provide the spring-loaded supports required to hold the free-standing heat source stack together during launch vibration. Details analysis indicates that the design offers a substantial improvement in specific power over the present generator of RTGs, using the same heat source modules. There are three copies in the file.

  11. Electricity Market Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the Electricity Market Module as it was used for the Annual Energy Outlook 2013. The Electricity Market Module (EMM) is the electricity supply component of the National Energy Modeling System (NEMS). The EMM represents the generation, transmission, and pricing of electricity. It consists of four submodules: the Electricity Capacity Planning (ECP) Submodule, the Electricity Fuel Dispatch (EFD) Submodule, the Electricity Finance and Pricing (EFP) Submodule, and the Electricity Load and Demand (ELD) Submodule.

  12. Spatio-temporal evolution of the postseismic slip associated with the 2005 Miyagi-Oki earthquake (M7.2) estimated from geodetic and seismological data

    NASA Astrophysics Data System (ADS)

    Iinuma, T.; Miura, S.; Uchida, N.; Sato, M.; Saito, H.; Ishikawa, T.; Hino, R.; Matsuzawa, T.

    2010-12-01

    On August 16, 2005, a M7.2 earthquake occurred along the plate boundary off Miyagi Prefecture, northeastern Japan, where the Pacific plate is subducting beneath the overriding continental plate at a rate of about 80 mm/yr. There are at least three asperities that were ruptured during the 1978 Miyagi-Oki earthquake (M7.4) there, and one or two of them were reruptured during the 2005 earthquake. We estimated spatio-temporal evolution of the postseismic slip associated with the 2005 Miyagi-Oki earthquake using continuous land GPS and campaign ocean bottom GPS/acoustic observation data in order to investigate whether the strain accumulation process at the unruptured asperities are affected by the event in 2005 or not. Daily site coordinates were estimated using a PPP (Precise Point Positioning) strategy of GIPSY-OASISII Software based on the GPS data observed at continuous sites operated by GSI (Geospatial Information Authority of Japan) and Tohoku University. Data from January 2004 to December 2007 have been analyzed. The linear trends with annual and semi-annual variations for the period from January 1, 2004 to August 15, 2005, and co-seismic displacements due to the main shock were estimated by least square modeling and subtracted from the original onshore GPS time series. As to the ocean bottom displacement data, we calculated secular velocities at the offshore site locations from an interplate coupling model based on the linear trends of land GPS sites and subtracted them from the observed time series. We regarded that the detrended time series represented the deformation due to the afterslip of the 2005 earthquake and were inverted them to obtain spatiotemporal slip distribution on the plate boundary by using a time dependent inversion analysis. We applied an inversion method devised by Yagi and Kikuchi (2003) to estimate the evolution of the fault slip in both space and time. We also estimated spatiotemporal evolution of the aseismic slip based on the activities

  13. Are the source models of the M 7.1 1908 Messina Straits earthquake reliable? Insights from a novel inversion and a sensitivity analysis of levelling data

    NASA Astrophysics Data System (ADS)

    Aloisi, M.; Bruno, V.; Cannavò, F.; Ferranti, L.; Mattia, M.; Monaco, C.; Palano, M.

    2013-03-01

    For decades, many authors have attempted to define the location, geometry and kinematics of the causative fault for the 1908 December 28, M 7.1 earthquake that struck the Messina Straits between Sicily and Calabria (southern Italy). The coseismic displacement caused a predominant downwarping of the Straits and small land uplift away from it, which were documented by levelling surveys performed 1 yr before and immediately after the earthquake. Most of the source models based on inversion of levelling data suggested that the earthquake was caused by a low angle, east-dipping blind normal fault, whose upper projection intersects the Earth surface on the Sicilian (west) side of the Messina Straits. An alternative interpretation holds that the causative fault is one of the high-angle, west-dipping faults located in southern Calabria, on the eastern side of the Straits, and may in large part coincide with the mapped Armo Fault. Here, we critically review the levelling data with the aim of defining both their usefulness and limits in modelling the seismogenic fault. We demonstrate that the levelling data alone are not capable of discriminating between the two oppositely dipping fault models, and thus their role as a keystone for modellers is untenable. However, new morphotectonic and geodetic data indicate that the Armo Fault has very recent activity and is accumulating strain. The surface observations, together with appraisal of macroseismic intensity distribution, available seismic tomography and marine geophysical evidence, lends credit to the hypothesis that the Armo and possibly the S. Eufemia faults are part of a major crustal structure that slipped during the 1908 earthquake.

  14. Source properties of earthquakes near the Salton Sea triggered by the 16 October 1999 M 7.1 Hector Mine, California, earthquake

    USGS Publications Warehouse

    Hough, S.E.; Kanamori, H.

    2002-01-01

    We analyze the source properties of a sequence of triggered earthquakes that occurred near the Salton Sea in southern California in the immediate aftermath of the M 7.1 Hector Mine earthquake of 16 October 1999. The sequence produced a number of early events that were not initially located by the regional network, including two moderate earthquakes: the first within 30 sec of the P-wave arrival and a second approximately 10 minutes after the mainshock. We use available amplitude and waveform data from these events to estimate magnitudes to be approximately 4.7 and 4.4, respectively, and to obtain crude estimates of their locations. The sequence of small events following the initial M 4.7 earthquake is clustered and suggestive of a local aftershock sequence. Using both broadband TriNet data and analog data from the Southern California Seismic Network (SCSN), we also investigate the spectral characteristics of the M 4.4 event and other triggered earthquakes using empirical Green's function (EGF) analysis. We find that the source spectra of the events are consistent with expectations for tectonic (brittle shear failure) earthquakes, and infer stress drop values of 0.1 to 6 MPa for six M 2.1 to M 4.4 events. The estimated stress drop values are within the range observed for tectonic earthquakes elsewhere. They are relatively low compared to typically observed stress drop values, which is consistent with expectations for faulting in an extensional, high heat flow regime. The results therefore suggest that, at least in this case, triggered earthquakes are associated with a brittle shear failure mechanism. This further suggests that triggered earthquakes may tend to occur in geothermal-volcanic regions because shear failure occurs at, and can be triggered by, relatively low stresses in extensional regimes.

  15. The 2007 M7.7 Tocopilla northern Chile earthquake sequence: Implications for along-strike and downdip rupture segmentation and megathrust frictional behavior

    NASA Astrophysics Data System (ADS)

    Schurr, B.; Asch, G.; Rosenau, M.; Wang, R.; Oncken, O.; Barrientos, S.; Salazar, P.; Vilotte, J.-P.

    2012-05-01

    In 2007 a M7.7 earthquake occurred near the town of Tocopilla within the northern Chile seismic gap. Main shock slip, derived from coseismic surface deformation, was confined to the depth range between 30 and 55 km. We relocated ˜1100 events during six months before and one week after the main shock. Aftershock seismicity is first congruent to the main shock slip and then it spreads offshore west and northwest of Mejillones Peninsula (MP). Waveform modeling for 38 aftershocks reveals source mechanisms that are in the majority similar to the main shock. However, a few events appear to occur in the upper plate, some with extensional mechanisms. Juxtaposing the Tocopilla aftershocks with those following the neighboring 1995 Antofagasta earthquake produces a striking symmetry across an EW axis in the center of MP. Events seem to skirt around MP, probably due to a shallower Moho there. We suggest that the seismogenic coupling zone in northern Chile changes its frictional behavior in the downdip direction from unstable to mostly conditionally stable. For both earthquake sequences, aftershocks agglomerate in the conditionally stable region, whereas maximum inter-seismic slip deficit and co-seismic slip occurs in the unstable region. The boundary between the unstable and conditionally stable zones parallels the coastline. We identify a similar segmentation for other earthquakes in Chile and Peru, where the offshore segments break in great M > 8 earthquakes, and the onshore segments in smaller M < 8 earthquakes. Using critical taper analysis, we demonstrate a causal relationship between varying slip behavior on the interface and forearc wedge anatomy that can be attributed to spatial variations in the rate-dependency of friction.

  16. Coseismic surface displacements from optical and SAR image offset tracking, fault modeling and geomorphological analysis of the Sept. 24th, 2013 M7.7 Balochistan earthquake

    NASA Astrophysics Data System (ADS)

    Harrington, Jonathan; Wang, Teng; Feng, Guangcai; Akoglu, Ahmet; Jónsson, Sigurjón; Motagh, Mahdi

    2014-05-01

    The M 7.7 earthquake in the Balochistan province of Pakistan on September 24th, 2013 took place along a subsidiary fault in the transition area between the Makran accretionary prism and the Chaman transform fault. This tectonics of the Indian and Arabian plate collisions with Eurasia produce primarily oblique left-lateral strike slip in this region. In this work, measurements of displacement and mapping of the rupture trace are achieved through image correlation of Landsat 8 images and SAR offset tracking of TerraSAR-X data. Horizontal displacements from both methods and derived vertical displacements are used to constrain a fault rupture model for the earthquake. Preliminary results show a surprisingly uniform slip distribution with maximum displacement near the surface. The total fault rupture length is ~210 km, with up to 9 m of left-lateral strike-slip and 3 m of reverse faulting. Additionally, mapping of the rupture trace is made use of for geomorphological observations relating to slip rates and identification of transpressional and transtensional features. Our results indicate a mostly smooth rupture trace, with the presence of two restraining steps, a releasing bend and a 3 km long sliver where the surface rupture jumped from the foot of the range-front into the alluvial fans at their base. A small block at one of the restraining steps shows intermediate displacement in both data sets. At the southern end of the rupture we observe that displacement from the earthquake cuts across a fold-and-thrust belt of the Makran accretionary prism. Preliminary results show a minimum of 12 km of repeated section of the accretionary wedge, and within the southern repeated section we find an offset of 600 m between two parallel ridges across the rupture trace. We relate these observations to conceptual models of fault segmentation and growth.

  17. Crustal structure of the northern margin of the eastern Tien Shan, China, and its tectonic implications for the 1906 M~7.7 Manas earthquake

    USGS Publications Warehouse

    Wang, Chun-Yong; Yang, Zhu-En; Luo, Hai; Mooney, W.D.

    2004-01-01

    The Tien Shan orogenic belt is the most active intracontinental mountain belt in the world. We describe an 86-km-long N–S-trending deep seismic reflection profile (which passes through the southern Junggar basin) located on the northeastern Tien Shan piedmont. Two distinct anticlines beneath the northern margin of the Tien Shan are clearly imaged in the seismic section. In addition, we have imaged two detachment surfaces at depths of ∼7 and ∼16 km. The detachment surface at 16-km depth corresponds to the main detachment that converges with the steep angle reverse fault (the Junggar Southern Marginal Fault) on which the 1906 M~7.7 Manas earthquake occurred. A 12–14-km-thick sedimentary basin is imaged beneath the southern Junggar basin near Shihezi. The crust beneath the northern margin of the Tien Shan is 50–55-km thick, and decreases beneath the Junggar basin to 40–45-km thick. The crustal image of the deep seismic reflection profile is consistent with models derived from nearby seismic refraction data and Bouguer gravity anomalies in the same region. The faulting associated with the 1906 Manas earthquake also fits within the structural framework imaged by the seismic reflection profile. Present-day micro-seismicity shows a hypocentral depth-distribution between 5 and 35 km, with a peak at 20 km. We hypothesize that the 1906 Manas earthquake initiated at a depth of ∼20 km and propagated upwards, causing northward slip on the sub-horizontal detachments beneath the southern Junggar basin. Thus, in accord with regional geological mapping, the current shortening within the eastern Tien Shan is accommodated both by high-angle reverse faulting and detachment faulting that can be clearly imaged at depth in seismic reflection data.

  18. Direct current modulation of a photomixing signal

    NASA Astrophysics Data System (ADS)

    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.

  19. Firefighting Module

    NASA Astrophysics Data System (ADS)

    1984-01-01

    Firefly II pump module is NASA's Marshall Space Flight Center's commercial offshoot of a NASA/US Coast Guard program involving development of a lightweight, helicopter-transportable firefighting module for a quick response in combating shipboard or harbor fires. Operable on land or water, the Amphib One is equipped with 3 water cannons. When all 3 are operating, unit pumps more than 3,000 gallons a minute. Newly developed model used by U.S. Coast Guard can pump 5,000 gallons per minute. It was designed for applications such as firefighting onboard ship fires, emergency dockside water pumping, dewatering ships in danger of sinking, flood control, and emergency water supply at remote locations.

  20. Thermoelectric module

    DOEpatents

    Kortier, William E.; Mueller, John J.; Eggers, Philip E.

    1980-07-08

    A thermoelectric module containing lead telluride as the thermoelectric mrial is encapsulated as tightly as possible in a stainless steel canister to provide minimum void volume in the canister. The lead telluride thermoelectric elements are pressure-contacted to a tungsten hot strap and metallurgically bonded at the cold junction to iron shoes with a barrier layer of tin telluride between the iron shoe and the p-type lead telluride element.