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Sample records for adaptive differential pulse

  1. Adaptive differential pulse-code modulation with adaptive bit allocation

    NASA Astrophysics Data System (ADS)

    Frangoulis, E. D.; Yoshida, K.; Turner, L. F.

    1984-08-01

    Studies have been conducted regarding the possibility to obtain good quality speech at data rates in the range from 16 kbit/s to 32 kbit/s. The techniques considered are related to adaptive predictive coding (APC) and adaptive differential pulse-code modulation (ADPCM). At 16 kbit/s adaptive transform coding (ATC) has also been used. The present investigation is concerned with a new method of speech coding. The described method employs adaptive bit allocation, similar to that used in adaptive transform coding, together with adaptive differential pulse-code modulation, employing first-order prediction. The new method has the objective to improve the quality of the speech over that which can be obtained with conventional ADPCM employing a fourth-order predictor. Attention is given to the ADPCM-AB system, the design of a subjective test, and the application of switched preemphasis to ADPCM.

  2. DIFFERENTIAL PULSE HEIGHT DISCRIMINATOR

    DOEpatents

    Test, L.D.

    1958-11-11

    Pulse-height discriminators are described, specifically a differential pulse-height discriminator which is adapted to respond to pulses of a band of amplitudes, but to reject pulses of amplitudes greater or less than tbe preselected band. In general, the discriminator includes a vacuum tube having a plurality of grids adapted to cut off plate current in the tube upon the application of sufficient negative voltage. One grid is held below cutoff, while a positive pulse proportional to the amplltude of each pulse is applled to this grid. Another grid has a negative pulse proportional to the amplitude of each pulse simultaneously applied to it. With this arrangement the tube will only pass pulses which are of sufficlent amplitude to counter the cutoff bias but not of sufficlent amplitude to cutoff the tube.

  3. Channel Error Propagation In Predictor Adaptive Differential Pulse Code Modulation (DPCM) Coders

    NASA Astrophysics Data System (ADS)

    Devarajan, Venkat; Rao, K. R.

    1980-11-01

    New adaptive differential pulse code modulation (ADPCM) coders with adaptive prediction are proposed and compared with existing non-adaptive DPCM coders, for processing composite National Television System Commission (NTSC) television signals. Comparisons are based on quantitative criteria as well as subjective evaluation of the processed still frames. The performance of the proposed predictors is shown to be independent of well-designed quantizers and better than existing predictors in such critical regions of the pictures as edges ind contours. Test data consists of four color images with varying levels of activity, color and detail. The adaptive predictors, however, are sensitive to channel errors. Propagation of transmission noise is dependent on the type of prediction and on location of noise i.e., whether in an uniform region or in an active region. The transmission error propagation for different predictors is investigated. By introducing leak in predictor output and/or predictor function it is shown that this propagation can be significantly reduced. The combination predictors not only attenuate and/or terminate the channel error propagation but also improve the predictor performance based on quantitative evaluation such as essential peak value and mean square error between the original and reconstructed images.

  4. Paired-Pulse Parietal-Motor Stimulation Differentially Modulates Corticospinal Excitability across Hemispheres When Combined with Prism Adaptation.

    PubMed

    Schintu, Selene; Martín-Arévalo, Elisa; Vesia, Michael; Rossetti, Yves; Salemme, Romeo; Pisella, Laure; Farnè, Alessandro; Reilly, Karen T

    2016-01-01

    Rightward prism adaptation ameliorates neglect symptoms while leftward prism adaptation (LPA) induces neglect-like biases in healthy individuals. Similarly, inhibitory repetitive transcranial magnetic stimulation (rTMS) on the right posterior parietal cortex (PPC) induces neglect-like behavior, whereas on the left PPC it ameliorates neglect symptoms and normalizes hyperexcitability of left hemisphere parietal-motor (PPC-M1) connectivity. Based on this analogy we hypothesized that LPA increases PPC-M1 excitability in the left hemisphere and decreases it in the right one. In an attempt to shed some light on the mechanisms underlying LPA's effects on cognition, we investigated this hypothesis in healthy individuals measuring PPC-M1 excitability with dual-site paired-pulse TMS (ppTMS). We found a left hemisphere increase and a right hemisphere decrease in the amplitude of motor evoked potentials elicited by paired as well as single pulses on M1. While this could indicate that LPA biases interhemispheric connectivity, it contradicts previous evidence that M1-only MEPs are unchanged after LPA. A control experiment showed that input-output curves were not affected by LPA per se. We conclude that LPA combined with ppTMS on PPC-M1 differentially alters the excitability of the left and right M1. PMID:27418979

  5. Paired-Pulse Parietal-Motor Stimulation Differentially Modulates Corticospinal Excitability across Hemispheres When Combined with Prism Adaptation

    PubMed Central

    Martín-Arévalo, Elisa; Salemme, Romeo; Pisella, Laure; Farnè, Alessandro

    2016-01-01

    Rightward prism adaptation ameliorates neglect symptoms while leftward prism adaptation (LPA) induces neglect-like biases in healthy individuals. Similarly, inhibitory repetitive transcranial magnetic stimulation (rTMS) on the right posterior parietal cortex (PPC) induces neglect-like behavior, whereas on the left PPC it ameliorates neglect symptoms and normalizes hyperexcitability of left hemisphere parietal-motor (PPC-M1) connectivity. Based on this analogy we hypothesized that LPA increases PPC-M1 excitability in the left hemisphere and decreases it in the right one. In an attempt to shed some light on the mechanisms underlying LPA's effects on cognition, we investigated this hypothesis in healthy individuals measuring PPC-M1 excitability with dual-site paired-pulse TMS (ppTMS). We found a left hemisphere increase and a right hemisphere decrease in the amplitude of motor evoked potentials elicited by paired as well as single pulses on M1. While this could indicate that LPA biases interhemispheric connectivity, it contradicts previous evidence that M1-only MEPs are unchanged after LPA. A control experiment showed that input-output curves were not affected by LPA per se. We conclude that LPA combined with ppTMS on PPC-M1 differentially alters the excitability of the left and right M1. PMID:27418979

  6. Errors associated with the use of adaptive differential pulse code modulation in the compression of isometric and dynamic myo-electric signals.

    PubMed

    Chan, A D; Lovely, D F; Hudgins, B

    1998-03-01

    Muscle activity produces an electrical signal termed the myo-electric signal (MES). The MES is a useful clinical tool, used in diagnostics and rehabilitation. This signal is typically stored in 2 bytes as 12-bit data, sampled at 3 kHz, resulting in a 6 kbyte s-1 storage requirement. Processing MES data requires large bit manipulations and heavy memory storage requirements. Adaptive differential pulse code modulation (ADPCM) is a popular and successful compression technique for speech. Its application to MES would reduce 12-bit data to a 4-bit representation, providing a 3:1 compression. As, in most practical applications, memory is organised in bytes, the realisable compression is 4:1, as pairs of data can be stored in a single byte. The performance of the ADPCM compression technique, using a real-time system at 1 kHz, 2 kHz and 4 kHz sampling rates, is evaluated. The data used include MES from both isometric and dynamic contractions. The percent residual difference (PRD) between an unprocessed and processed MES is used as a performance measure. Errors in computed parameters, such as median frequency and variance, which are used in clinical diagnostics, and waveform features employed in prosthetic control are also used to evaluate the system. The results of the study demonstrate that the ADPCM compression technique is an excellent solution for relieving the data storage requirements of MES both in isometric and dynamic situations. PMID:9684462

  7. Recursively indexed differential pulse code modulation

    NASA Technical Reports Server (NTRS)

    Sayood, Khalid; Na, Sangsin

    1992-01-01

    The performance of a differential pulse code modulation (DPCM) system with a recursively indexed quantizer (RIQ) under various conditions, with first order Gauss-Markov and Laplace-Markov sources as inputs, is studied. When the predictor is matched to the input, the proposed system performs at or close to the optimum entropy constrained DPCM system. If one is willing to accept a 5 percent increase in the rate, the system is very forgiving of predictor mismatch.

  8. Adaptive control system for pulsed megawatt klystrons

    DOEpatents

    Bolie, Victor W.

    1992-01-01

    The invention provides an arrangement for reducing waveform errors such as errors in phase or amplitude in output pulses produced by pulsed power output devices such as klystrons by generating an error voltage representing the extent of error still present in the trailing edge of the previous output pulse, using the error voltage to provide a stored control voltage, and applying the stored control voltage to the pulsed power output device to limit the extent of error in the leading edge of the next output pulse.

  9. Adaptive group coordination and role differentiation.

    PubMed

    Roberts, Michael E; Goldstone, Robert L

    2011-01-01

    Many real world situations (potluck dinners, academic departments, sports teams, corporate divisions, committees, seminar classes, etc.) involve actors adjusting their contributions in order to achieve a mutually satisfactory group goal, a win-win result. However, the majority of human group research has involved situations where groups perform poorly because task constraints promote either individual maximization behavior or diffusion of responsibility, and even successful tasks generally involve the propagation of one correct solution through a group. Here we introduce a group task that requires complementary actions among participants in order to reach a shared goal. Without communication, group members submit numbers in an attempt to collectively sum to a randomly selected target number. After receiving group feedback, members adjust their submitted numbers until the target number is reached. For all groups, performance improves with task experience, and group reactivity decreases over rounds. Our empirical results provide evidence for adaptive coordination in human groups, and as the coordination costs increase with group size, large groups adapt through spontaneous role differentiation and self-consistency among members. We suggest several agent-based models with different rules for agent reactions, and we show that the empirical results are best fit by a flexible, adaptive agent strategy in which agents decrease their reactions when the group feedback changes. The task offers a simple experimental platform for studying the general problem of group coordination while maximizing group returns, and we distinguish the task from several games in behavioral game theory. PMID:21811595

  10. Pulse transit time differential measurement by fiber Bragg grating pulse recorder.

    PubMed

    Umesh, Sharath; Padma, Srivani; Ambastha, Shikha; Kalegowda, Anand; Asokan, Sundarrajan

    2015-05-01

    The present study reports a noninvasive technique for the measurement of the pulse transit time differential (PTTD) from the pulse pressure waveforms obtained at the carotid artery and radial artery using fiber Bragg grating pulse recorders (FBGPR). PTTD is defined as the time difference between the arrivals of a pulse pressure waveform at the carotid and radial arterial sites. The PTTD is investigated as an indicator of variation in the systolic blood pressure. The results are validated against blood pressure variation obtained from a Mindray Patient Monitor. Furthermore, the pulse wave velocity computed from the obtained PTTD is compared with the pulse wave velocity obtained from the color Doppler ultrasound system and is found to be in good agreement. The major advantage of the PTTD measurement via FBGPRs is that the data acquisition system employed can simultaneously acquire pulse pressure waveforms from both FBGPRs placed at carotid and radial arterial sites with a single time scale, which eliminates time synchronization complexity. PMID:26021719

  11. Pulse transit time differential measurement by fiber Bragg grating pulse recorder

    NASA Astrophysics Data System (ADS)

    Umesh, Sharath; Padma, Srivani; Ambastha, Shikha; Kalegowda, Anand; Asokan, Sundarrajan

    2015-05-01

    The present study reports a noninvasive technique for the measurement of the pulse transit time differential (PTTD) from the pulse pressure waveforms obtained at the carotid artery and radial artery using fiber Bragg grating pulse recorders (FBGPR). PTTD is defined as the time difference between the arrivals of a pulse pressure waveform at the carotid and radial arterial sites. The PTTD is investigated as an indicator of variation in the systolic blood pressure. The results are validated against blood pressure variation obtained from a Mindray Patient Monitor. Furthermore, the pulse wave velocity computed from the obtained PTTD is compared with the pulse wave velocity obtained from the color Doppler ultrasound system and is found to be in good agreement. The major advantage of the PTTD measurement via FBGPRs is that the data acquisition system employed can simultaneously acquire pulse pressure waveforms from both FBGPRs placed at carotid and radial arterial sites with a single time scale, which eliminates time synchronization complexity.

  12. Single pulse TMS differentially modulates reward behavior.

    PubMed

    Stanford, Arielle D; Luber, Bruce; Unger, Layla; Cycowicz, Yael M; Malaspina, Dolores; Lisanby, Sarah H

    2013-12-01

    Greater knowledge of cortical brain regions in reward processing may set the stage for using transcranial magnetic stimulation (TMS) as a treatment in patients with avolition, apathy or other drive-related symptoms. This study examined the effects of single pulse (sp) TMS to two reward circuit targets on drive in healthy subjects. Fifteen healthy subjects performed the monetary incentive delay task (MID) while receiving fMRI-guided spTMS to either inferior parietal lobe (IPL) or supplemental motor area (SMA). The study demonstrated decreasing reaction times (RT) for increasing reward. It also showed significant differences in RT modulation for TMS pulses to the IPL versus the SMA. TMS pulses during the delay period produced significantly more RT slowing when targeting the IPL than those to the SMA. This RT slowing carried over into subsequent trials without TMS stimulation, with significantly slower RTs in sessions that had targeted the IPL compared to those targeting SMA. The results of this study suggest that both SMA and IPL are involved in reward processing, with opposite effects on RT in response to TMS stimulation. TMS to these target cortical regions may be useful in modulating reward circuit deficits in psychiatric populations.

  13. Radar Range Sidelobe Reduction Using Adaptive Pulse Compression Technique

    NASA Technical Reports Server (NTRS)

    Li, Lihua; Coon, Michael; McLinden, Matthew

    2013-01-01

    Pulse compression has been widely used in radars so that low-power, long RF pulses can be transmitted, rather than a highpower short pulse. Pulse compression radars offer a number of advantages over high-power short pulsed radars, such as no need of high-power RF circuitry, no need of high-voltage electronics, compact size and light weight, better range resolution, and better reliability. However, range sidelobe associated with pulse compression has prevented the use of this technique on spaceborne radars since surface returns detected by range sidelobes may mask the returns from a nearby weak cloud or precipitation particles. Research on adaptive pulse compression was carried out utilizing a field-programmable gate array (FPGA) waveform generation board and a radar transceiver simulator. The results have shown significant improvements in pulse compression sidelobe performance. Microwave and millimeter-wave radars present many technological challenges for Earth and planetary science applications. The traditional tube-based radars use high-voltage power supply/modulators and high-power RF transmitters; therefore, these radars usually have large size, heavy weight, and reliability issues for space and airborne platforms. Pulse compression technology has provided a path toward meeting many of these radar challenges. Recent advances in digital waveform generation, digital receivers, and solid-state power amplifiers have opened a new era for applying pulse compression to the development of compact and high-performance airborne and spaceborne remote sensing radars. The primary objective of this innovative effort is to develop and test a new pulse compression technique to achieve ultrarange sidelobes so that this technique can be applied to spaceborne, airborne, and ground-based remote sensing radars to meet future science requirements. By using digital waveform generation, digital receiver, and solid-state power amplifier technologies, this improved pulse compression

  14. Pulsed laser deposition: the road to hybrid nanocomposites coatings and novel pulsed laser adaptive technique.

    PubMed

    Serbezov, Valery

    2013-01-01

    The applications of Pulsed Laser Deposition (PLD) for producing nanoparticles, nanostructures and nanocomposites coatings based on recently developed laser ablating techniques and their convergence are being reviewed. The problems of in situ synthesis of hybrid inorganic-organic nanocomposites coatings by these techniques are being discussed. The novel modification of PLD called Pulsed Laser Adaptive Deposition (PLAD) technique is presented. The in situ synthesized inorganic/organic nanocomposites coatings from Magnesium (Mg) alloy/Rhodamine B and Mg alloy/ Desoximetasone by PLAD are described. The trends, applications and future development of discussed patented methods based on the laser ablating technologies for producing hybrid nanocomposite coatings have also been discussed in this review.

  15. Adaptive numerical methods for partial differential equations

    SciTech Connect

    Cololla, P.

    1995-07-01

    This review describes a structured approach to adaptivity. The Automated Mesh Refinement (ARM) algorithms developed by M Berger are described, touching on hyperbolic and parabolic applications. Adaptivity is achieved by overlaying finer grids only in areas flagged by a generalized error criterion. The author discusses some of the issues involved in abutting disparate-resolution grids, and demonstrates that suitable algorithms exist for dissipative as well as hyperbolic systems.

  16. Adaptive pulse width control and sampling for low power pulse oximetry.

    PubMed

    Gubbi, Sagar Venkatesh; Amrutur, Bharadwaj

    2015-04-01

    Remote sensing of physiological parameters could be a cost effective approach to improving health care, and low-power sensors are essential for remote sensing because these sensors are often energy constrained. This paper presents a power optimized photoplethysmographic sensor interface to sense arterial oxygen saturation, a technique to dynamically trade off SNR for power during sensor operation, and a simple algorithm to choose when to acquire samples in photoplethysmography. A prototype of the proposed pulse oximeter built using commercial-off-the-shelf (COTS) components is tested on 10 adults. The dynamic adaptation techniques described reduce power consumption considerably compared to our reference implementation, and our approach is competitive to state-of-the-art implementations. The techniques presented in this paper may be applied to low-power sensor interface designs where acquiring samples is expensive in terms of power as epitomized by pulse oximetry. PMID:25014964

  17. Adaptive optics for ultra short pulsed lasers in UHV environment

    NASA Astrophysics Data System (ADS)

    Deneuville, Francois; Ropert, Laurent; Sauvageot, Paul; Theis, Sébastien

    2015-02-01

    ISP SYSTEM has developed an electro-mechanical deformable mirror compatible with Ultra High Vacuum environment, suitable for ultra short pulsed lasers. The design of the MD-AME deformable mirror is based on force application on numerous locations. μ-AME actuators are driven by stepper motors, and their patented special design allows controlling the force with a very high accuracy. Materials and assembly method have been adapted to UHV constraints and the performances were evaluated on a first application for a beam with a diameter of 250mm. A Strehl ratio above 0.9 was reached for this application. Optical aberrations up to Zernike order 5 can be corrected with a very low residual error as for standard MD-AME mirror. Amplitude can reach up to several hundreds of μm for low order corrections. Hysteresis is lower than 0.1% and linearity better than 99%. Contrary to piezo-electric actuators, the μ-AME actuators avoid print-through effects and they permit to keep the mirror shape stable even unpowered, providing a high resistance to electro-magnetic pulses. The deformable mirror design allows changing easily an actuator or even the membrane if needed, in order to improve the facility availability. They are designed for circular, square or elliptical aperture from 30mm up to 500mm or more, with incidence angle from 0° to 45°. They can be equipped with passive or active cooling for high power lasers with high repetition rate.

  18. An Adaptive Unified Differential Evolution Algorithm for Global Optimization

    SciTech Connect

    Qiang, Ji; Mitchell, Chad

    2014-11-03

    In this paper, we propose a new adaptive unified differential evolution algorithm for single-objective global optimization. Instead of the multiple mutation strate- gies proposed in conventional differential evolution algorithms, this algorithm employs a single equation unifying multiple strategies into one expression. It has the virtue of mathematical simplicity and also provides users the flexibility for broader exploration of the space of mutation operators. By making all control parameters in the proposed algorithm self-adaptively evolve during the process of optimization, it frees the application users from the burden of choosing appro- priate control parameters and also improves the performance of the algorithm. In numerical tests using thirteen basic unimodal and multimodal functions, the proposed adaptive unified algorithm shows promising performance in compari- son to several conventional differential evolution algorithms.

  19. Reconfigurable symmetric pulses generation using on-chip cascaded optical differentiators.

    PubMed

    Hou, Jie; Dong, Jianji; Zhang, Xinliang

    2016-09-01

    We report a type of programmable pulse shaping method based on cascaded frequency-detuned optical differentiators. By properly adjusting the central wavelength of each differentiator, a large variety of symmetric pulses can be generated from a transform-limited Gaussian-like pulse. We numerically and experimentally demonstrate the generation of flat-top, parabolic and triangular pulses with tunable pulse widths from a 20-ps Gaussian-like pulse, using no more than three cascaded differentiators. It can be found that as more differentiators are used, higher synthesized accuracy and larger tuning range of pulse widths can be obtained in general. Additionally, in our experiment, we design and fabricate thermally tunable delay interferometers on the silicon-on-insulator (SOI) platform to work as optical differentiators, which can help us realize the shaping system with small footprint (943μm × 395μm) and high stability. PMID:27607657

  20. Reconfigurable symmetric pulses generation using on-chip cascaded optical differentiators.

    PubMed

    Hou, Jie; Dong, Jianji; Zhang, Xinliang

    2016-09-01

    We report a type of programmable pulse shaping method based on cascaded frequency-detuned optical differentiators. By properly adjusting the central wavelength of each differentiator, a large variety of symmetric pulses can be generated from a transform-limited Gaussian-like pulse. We numerically and experimentally demonstrate the generation of flat-top, parabolic and triangular pulses with tunable pulse widths from a 20-ps Gaussian-like pulse, using no more than three cascaded differentiators. It can be found that as more differentiators are used, higher synthesized accuracy and larger tuning range of pulse widths can be obtained in general. Additionally, in our experiment, we design and fabricate thermally tunable delay interferometers on the silicon-on-insulator (SOI) platform to work as optical differentiators, which can help us realize the shaping system with small footprint (943μm × 395μm) and high stability.

  1. Determination of Zalcitabine in Medicaments by Differential Pulse Voltammetry

    PubMed Central

    Leandro, Katia Christina; Moreira, Josino Costa; Farias, Pércio Augusto Mardini

    2013-01-01

    The zalcitabine (ddC) has been extensively used in the treatment of HIV patients due to its antiretroviral activity. The quality control of this active principle in medications is of outstanding importance to public health. The principal objective of the current study was the development of an alternative analytical methodology for the zalcitabine determination using a voltammetric process. The zalcitabine gives a reduction peak (at −1.22 V versus Ag/AgCl) at the hanging mercury drop electrode (HMDE). The differential pulse voltammetric response is evaluated with respect to the scan rate (20 mV/s), pulse amplitude (50 mV), support electrolyte (Clark-Lubs buffer), pH (2.0), and other variables. The response is linear over the 10.0 to 28.0 mg/L (47 to 133 μM) concentration range, and the detection limit is 2.08 mg/L. The validation of this method was realized using a governmental Brazilian document (Inmetro, 2007) and the results are reported for medication drugs. PMID:26555981

  2. Aortic pulse pressure homeostasis emerges from physiological adaptation of systemic arteries to local mechanical stresses.

    PubMed

    Nguyen, Phuc H; Tuzun, Egemen; Quick, Christopher M

    2016-09-01

    Aortic pulse pressure arises from the interaction of the heart, the systemic arterial system, and peripheral microcirculations. The complex interaction between hemodynamics and arterial remodeling precludes the ability to experimentally ascribe changes in aortic pulse pressure to particular adaptive responses. Therefore, the purpose of the present work was to use a human systemic arterial system model to test the hypothesis that pulse pressure homeostasis can emerge from physiological adaptation of systemic arteries to local mechanical stresses. First, we assumed a systemic arterial system that had a realistic topology consisting of 121 arterial segments. Then the relationships of pulsatile blood pressures and flows in arterial segments were characterized by standard pulse transmission equations. Finally, each arterial segment was assumed to remodel to local stresses following three simple rules: 1) increases in endothelial shear stress increases radius, 2) increases in wall circumferential stress increases wall thickness, and 3) increases in wall circumferential stress decreases wall stiffness. Simulation of adaptation by iteratively calculating pulsatile hemodynamics, mechanical stresses, and vascular remodeling led to a general behavior in response to mechanical perturbations: initial increases in pulse pressure led to increased arterial compliances, and decreases in pulse pressure led to decreased compliances. Consequently, vascular adaptation returned pulse pressures back toward baseline conditions. This behavior manifested when modeling physiological adaptive responses to changes in cardiac output, changes in peripheral resistances, and changes in local arterial radii. The present work, thus, revealed that pulse pressure homeostasis emerges from physiological adaptation of systemic arteries to local mechanical stresses.

  3. Remotely detected differential pulse transit time as a stress indicator

    NASA Astrophysics Data System (ADS)

    Kaur, Balvinder; Tarbox, Elizabeth; Cissel, Marty; Moses, Sophia; Luthra, Megha; Vaidya, Misha; Tran, Nhien; Ikonomidou, Vasiliki N.

    2015-05-01

    The human cardiovascular system, controlled by the autonomic nervous system (ANS), is one of the first sites where one can see the "fight-or-flight" response due to the presence of external stressors. In this paper, we investigate the possibility of detecting mental stress using a novel measure that can be measured in a contactless manner: Pulse transit time (dPTT), which refers to the time that is required for the blood wave (BW) to cover the distance from the heart to a defined remote location in the body. Loosely related to blood pressure, PTT is a measure of blood velocity, and is also implicated in the "fight-or-flight" response. We define the differential PTT (dPTT) as the difference in PTT between two remote areas of the body, such as the forehead and the palm. Expanding our previous work on remote BW detection from visible spectrum videos, we built a system that remotely measures dPTT. Human subject data were collected under an IRB approved protocol from 15 subjects both under normal and stress states and are used to initially establish the potential use of remote dPPT detection as a stress indicator.

  4. Genetic analysis of population differentiation and adaptation in Leuciscus waleckii.

    PubMed

    Chang, Yumei; Tang, Ran; Sun, Xiaowen; Liang, Liqun; Chen, Jinping; Huang, Jinfeng; Dou, Xinjie; Tao, Ran

    2013-12-01

    Demographic events and natural selection both influence animal phenotypic and genetic variation; exploring the effects of demography and selection on population divergence is of great significance in evolutionary biology. To uncover the causes behind the patterns of genetic differentiation and adaptation among six populations of Leuciscus waleckii from Dali Basin (two populations, alkaline vs. freshwater) and Amur Basin (four populations, freshwater rivers vs. alkaline lake), a set of 21 unlinked polymorphic microsatellite markers and two mitochondrial DNA sequences (Cytb and D-loop) were applied to examine whether populations from different environments or habitats have distinct genetic differentiation and whether alkalinity is the major factor that caused population divergence. Bayesian analysis and principal component analysis as well as haplotype network analysis showed that these populations are primarily divided into two groups, which are congruent with geographic separation but not inconsistent with the habitat environment (alkalinity). Using three different approaches, outlier detection indicated that one locus, HLJYL017, may be under directional selection and involved in local adaptation processes. Overall, this study suggested that demographic events and selection of local environmental conditions including of alkalinity are jointly responsible for population divergence. These findings constitute an important step towards the understanding of the genetic basis of differentiation and adaptation, as well as towards the conservation of L. waleckii.

  5. GPU-based parallel clustered differential pulse code modulation

    NASA Astrophysics Data System (ADS)

    Wu, Jiaji; Li, Wenze; Kong, Wanqiu

    2015-10-01

    Hyperspectral remote sensing technology is widely used in marine remote sensing, geological exploration, atmospheric and environmental remote sensing. Owing to the rapid development of hyperspectral remote sensing technology, resolution of hyperspectral image has got a huge boost. Thus data size of hyperspectral image is becoming larger. In order to reduce their saving and transmission cost, lossless compression for hyperspectral image has become an important research topic. In recent years, large numbers of algorithms have been proposed to reduce the redundancy between different spectra. Among of them, the most classical and expansible algorithm is the Clustered Differential Pulse Code Modulation (CDPCM) algorithm. This algorithm contains three parts: first clusters all spectral lines, then trains linear predictors for each band. Secondly, use these predictors to predict pixels, and get the residual image by subtraction between original image and predicted image. Finally, encode the residual image. However, the process of calculating predictors is timecosting. In order to improve the processing speed, we propose a parallel C-DPCM based on CUDA (Compute Unified Device Architecture) with GPU. Recently, general-purpose computing based on GPUs has been greatly developed. The capacity of GPU improves rapidly by increasing the number of processing units and storage control units. CUDA is a parallel computing platform and programming model created by NVIDIA. It gives developers direct access to the virtual instruction set and memory of the parallel computational elements in GPUs. Our core idea is to achieve the calculation of predictors in parallel. By respectively adopting global memory, shared memory and register memory, we finally get a decent speedup.

  6. Magnetization transfer characteristics in atherosclerotic plaque components assessed by adapted binomial preparation pulses.

    PubMed

    Pachot-Clouard, M; Vaufrey, F; Darrasse, L; Toussainti, J F

    1998-11-01

    Increasing the contrast between atheromatous plaque components is a major issue in cardiovascular MRI research. It would allow one to identify unstable plaque by differentiating the lipid core associated with vulnerability, from the fibrous cap, considered as a factor of stability. T2 and diffusion-weighted imaging have already provided satisfying results. Magnetization transfer (MT) between restricted protons Hr and free-water protons Hf could achieve a different contrast related to collagen and lipoprotein macromolecules present in the fibrous cap and lipid core, respectively. The purpose of this work was to evaluate in vitro the MT effect produced by adapted T2-selective 1-3-3-1 binomial pulses on isolated samples of atheromatous arteries at 3 T. A method based on simulation was used in order to improve the MT specificity: it is shown that 50% 1-3-3-1 pulses (the percentage indicating the level of Hr saturation) allow an estimation of T2r, the Hr T2. Using this technique, magnetization transfer was observed for the first time in atherosclerotic plaque components, an effect more pronounced for the fibrous cap and media than for the lipid core and adventitia. The T2r estimation gave values ranging from 20 to 25 micros for the four samples. This preliminary study provides a basis for establishing an MT imaging sequence of atheromatous arteries, by using 50% 1-3-3-1 pulses calibrated for saturating protons with a 20 micros T2. This MT protocol should be further compared to T2 and diffusion-weighted imaging. PMID:9877454

  7. Effects of pulsed electromagnetic field frequencies on the osteogenic differentiation of human mesenchymal stem cells.

    PubMed

    Luo, Fei; Hou, Tianyong; Zhang, Zehua; Xie, Zhao; Wu, Xuehui; Xu, Jianzhong

    2012-04-01

    The purpose of this study was to evaluate the effect of different frequencies of pulsed electromagnetic fields on the osteogenic differentiation of human mesenchymal stem cells. Third-generation human mesenchymal stem cells were irradiated with different frequencies of pulsed electromagnetic fields, including 5, 25, 50, 75, 100, and 150 Hz, with a field intensity of 1.1 mT, for 30 minutes per day for 21 days. Changes in human mesenchymal stem cell morphology were observed using phase contrast microscopy. Alkaline phosphatase activity and osteocalcin expression were also determined to evaluate human mesenchymal stem cell osteogenic differentiation.Different effects were observed on human mesenchymal stem cell osteoblast induction following exposure to different pulsed electromagnetic field frequencies. Levels of human mesenchymal stem cell differentiation increased when the pulsed electromagnetic field frequency was increased from 5 hz to 50 hz, but the effect was weaker when the pulsed electromagnetic field frequency was increased from 50 Hz to 150 hz. The most significant effect on human mesenchymal stem cell differentiation was observed at of 50 hz.The results of the current study show that pulsed electromagnetic field frequency is an important factor with regard to the induction of human mesenchymal stem cell differentiation. Furthermore, a pulsed electromagnetic field frequency of 50 Hz was the most effective at inducing human mesenchymal stem cell osteoblast differentiation in vitro.

  8. Final Report: Symposium on Adaptive Methods for Partial Differential Equations

    SciTech Connect

    Pernice, M.; Johnson, C.R.; Smith, P.J.; Fogelson, A.

    1998-12-10

    OAK-B135 Final Report: Symposium on Adaptive Methods for Partial Differential Equations. Complex physical phenomena often include features that span a wide range of spatial and temporal scales. Accurate simulation of such phenomena can be difficult to obtain, and computations that are under-resolved can even exhibit spurious features. While it is possible to resolve small scale features by increasing the number of grid points, global grid refinement can quickly lead to problems that are intractable, even on the largest available computing facilities. These constraints are particularly severe for three dimensional problems that involve complex physics. One way to achieve the needed resolution is to refine the computational mesh locally, in only those regions where enhanced resolution is required. Adaptive solution methods concentrate computational effort in regions where it is most needed. These methods have been successfully applied to a wide variety of problems in computational science and engineering. Adaptive methods can be difficult to implement, prompting the development of tools and environments to facilitate their use. To ensure that the results of their efforts are useful, algorithm and tool developers must maintain close communication with application specialists. Conversely it remains difficult for application specialists who are unfamiliar with the methods to evaluate the trade-offs between the benefits of enhanced local resolution and the effort needed to implement an adaptive solution method.

  9. Adaptive Control of a Transport Aircraft Using Differential Thrust

    NASA Technical Reports Server (NTRS)

    Stepanyan, Vahram; Krishnakumar, Kalmanje; Nguyen, Nhan

    2009-01-01

    The paper presents an adaptive control technique for a damaged large transport aircraft subject to unknown atmospheric disturbances such as wind gust or turbulence. It is assumed that the damage results in vertical tail loss with no rudder authority, which is replaced with a differential thrust input. The proposed technique uses the adaptive prediction based control design in conjunction with the time scale separation principle, based on the singular perturbation theory. The application of later is necessitated by the fact that the engine response to a throttle command is substantially slow that the angular rate dynamics of the aircraft. It is shown that this control technique guarantees the stability of the closed-loop system and the tracking of a given reference model. The simulation example shows the benefits of the approach.

  10. Differential-phase-shift quantum key distribution with segmented pulse trains

    SciTech Connect

    Kawahara, Hiroki; Inoue, Kyo

    2011-06-15

    We present a modified scheme of differential-phase-shift (DPS) quantum key distribution (QKD) for improving its performance. A transmitter sends a weak coherent pulse train segmented with vacant pulses. Then, a receiver can find eavesdropping by monitoring the photon detection rate at particular time slots. Simulations show that the proposed scheme is robust against a sequential attack and a general individual attack.

  11. On the adaptivity and complexity embedded into differential evolution

    NASA Astrophysics Data System (ADS)

    Senkerik, Roman; Pluhacek, Michal; Zelinka, Ivan; Jasek, Roman

    2016-06-01

    This research deals with the comparison of the two modern approaches for evolutionary algorithms, which are the adaptivity and complex chaotic dynamics. This paper aims on the investigations on the chaos-driven Differential Evolution (DE) concept. This paper is aimed at the embedding of discrete dissipative chaotic systems in the form of chaotic pseudo random number generators for the DE and comparing the influence to the performance with the state of the art adaptive representative jDE. This research is focused mainly on the possible disadvantages and advantages of both compared approaches. Repeated simulations for Lozi map driving chaotic systems were performed on the simple benchmark functions set, which are more close to the real optimization problems. Obtained results are compared with the canonical not-chaotic and not adaptive DE. Results show that with used simple test functions, the performance of ChaosDE is better in the most cases than jDE and Canonical DE, furthermore due to the unique sequencing in CPRNG given by the hidden chaotic dynamics, thus better and faster selection of unique individuals from population, ChaosDE is faster.

  12. Pulsed DC Electric Field–Induced Differentiation of Cortical Neural Precursor Cells

    PubMed Central

    Chang, Hui-Fang; Lee, Ying-Shan; Tang, Tang K.; Cheng, Ji-Yen

    2016-01-01

    We report the differentiation of neural stem and progenitor cells solely induced by direct current (DC) pulses stimulation. Neural stem and progenitor cells in the adult mammalian brain are promising candidates for the development of therapeutic neuroregeneration strategies. The differentiation of neural stem and progenitor cells depends on various in vivo environmental factors, such as nerve growth factor and endogenous EF. In this study, we demonstrated that the morphologic and phenotypic changes of mouse neural stem and progenitor cells (mNPCs) could be induced solely by exposure to square-wave DC pulses (magnitude 300 mV/mm at frequency of 100-Hz). The DC pulse stimulation was conducted for 48 h, and the morphologic changes of mNPCs were monitored continuously. The length of primary processes and the amount of branching significantly increased after stimulation by DC pulses for 48 h. After DC pulse treatment, the mNPCs differentiated into neurons, astrocytes, and oligodendrocytes simultaneously in stem cell maintenance medium. Our results suggest that simple DC pulse treatment could control the fate of NPCs. With further studies, DC pulses may be applied to manipulate NPC differentiation and may be used for the development of therapeutic strategies that employ NPCs to treat nervous system disorders. PMID:27352251

  13. Remote sensing image subpixel mapping based on adaptive differential evolution.

    PubMed

    Zhong, Yanfei; Zhang, Liangpei

    2012-10-01

    In this paper, a novel subpixel mapping algorithm based on an adaptive differential evolution (DE) algorithm, namely, adaptive-DE subpixel mapping (ADESM), is developed to perform the subpixel mapping task for remote sensing images. Subpixel mapping may provide a fine-resolution map of class labels from coarser spectral unmixing fraction images, with the assumption of spatial dependence. In ADESM, to utilize DE, the subpixel mapping problem is transformed into an optimization problem by maximizing the spatial dependence index. The traditional DE algorithm is an efficient and powerful population-based stochastic global optimizer in continuous optimization problems, but it cannot be applied to the subpixel mapping problem in a discrete search space. In addition, it is not an easy task to properly set control parameters in DE. To avoid these problems, this paper utilizes an adaptive strategy without user-defined parameters, and a reversible-conversion strategy between continuous space and discrete space, to improve the classical DE algorithm. During the process of evolution, they are further improved by enhanced evolution operators, e.g., mutation, crossover, repair, exchange, insertion, and an effective local search to generate new candidate solutions. Experimental results using different types of remote images show that the ADESM algorithm consistently outperforms the previous subpixel mapping algorithms in all the experiments. Based on sensitivity analysis, ADESM, with its self-adaptive control parameter setting, is better than, or at least comparable to, the standard DE algorithm, when considering the accuracy of subpixel mapping, and hence provides an effective new approach to subpixel mapping for remote sensing imagery.

  14. High-gain digital speech interpolation with adaptive differential PCM encoding

    NASA Astrophysics Data System (ADS)

    Yatsuzuka, Y.

    1982-04-01

    A generalization of digital speech interpolation (DSI) combined with adaptive differential pulse-code modulation (ADPCM) is described. The general configuration of the DSI-ADPCM system is detailed, and the speech encoding strategy in a heavily loaded environment is described. Advantages obtained by incorporating a voiceband data discriminator into the DSI-ADPCM are discussed. The ADPCM encoding with voiceband shifts and sampling rate conversions is analyzed and the simulated performance of the ADPCM encoding is described in terms of a long-time averaged signal-to-noise ratio and subjective quality of the processed speech. For voiceband data, long-time averaged signal-to-noise ratios relevant to 4.8 kbit/s eight-phase PSK and 9.6 kbit/s 16-point QAM voiceband data are given.

  15. Genetic Differentiation and Evolutionary Adaptation in Cryptomeria japonica

    PubMed Central

    Tsumura, Yoshihiko; Uchiyama, Kentaro; Moriguchi, Yoshinari; Kimura, Megumi K.; Ueno, Saneyoshi; Ujino-Ihara, Tokuko

    2014-01-01

    Local adaptation of plant species is a central issue for survival during global climate change, especially for long-lived forest trees, with their lengthy regeneration time and spatially limited gene flow. Identification of loci and/or genomic regions associated with local adaptation is necessary for knowledge of both evolution and molecular breeding for climate change. Cryptomeria japonica is an important species for forestry in Japan; it has a broad natural distribution and can survive in a range of different environments. The genetic structure of 14 natural populations of this species was investigated using 3930 SNP markers. Populations on the Pacific Ocean side of Japan are clearly different from those on the Japan Sea side, as discussed in previous studies. Structure analysis and population network trees show that peripheral populations, including the most northerly and southerly ones, have unique features. We found that the genetic differentiation coefficient is low, FST = 0.05, although it must account for the presence of important genes associated with adaptation to specific environments. In total, 208 outlier loci were detected, of which 43 were associated with environmental variables. Four clumped regions of outlier loci were detected in the genome by linkage analysis. Linkage disequilibrium (LD) was quite high in these clumps of outlier loci, which were found in linkage groups (LGs) 2, 7, 10, and 11, especially between populations of two varieties, and when interchromosomal LD was also detected. The LG7 region is characteristic of the Yakushima population, which is a large, isolated, peripheral population occupying a specific environment resulting from isolation combined with volcanic activity in the region. The detected LD may provide strong evidence for selection between varieties. PMID:25320072

  16. Controlling Scattering Instabilities and Adapting to Unknown and Changing Plasma Conditions Using STUD Pulses

    NASA Astrophysics Data System (ADS)

    Afeyan, Bedros; Hüller, Stefan

    2012-10-01

    We will show the results of changing STUD pulse configurations in order to maintain strict control of parametric instabilities in high energy density plasmas (HEDP). Nonlinear optical processes (NLOP) in HEDP respond to changing plasma conditions which are unknown and not easily knowable by standard experimental procedures. Adapting to changing and unknown plasma conditions is one feature of STUD pulses which is absent in other beam conditioning techniques. We demonstrate this by simulating long enough that plasma conditions change, instability gains are altered and new STUD pulse configurations become necessary. Two such configurations are spliced together or run independently and compared. All available methods of changing STUD pulse characteristics are explored, such as duty cycle (20% vs 50%) and modulation period (cutting hot spots in half and into quarters) as well as phase scrambling and number of spikes before the spatial distribution of hot spots is randomized (1, 2, 3 and infinity).

  17. High energy femtosecond fiber chirped pulse amplification system with adaptive phase control.

    PubMed

    He, F; Hung, H S S; Price, J H V; Daga, N K; Naz, N; Prawiharjo, J; Hanna, D C; Shepherd, D P; Richardson, D J; Dawson, J W; Siders, C W; Barty, C P

    2008-04-14

    We demonstrate increased peak power from an Yb fiber CPA system operating with strong self-phase modulation by shaping the spectral-phase of the input pulses. An adaptive control loop used feedback from the output autocorrelation. We investigated pre-compensation of both SPM phase distortion at high energies, and residual dispersion from mismatched stretcher/compressor technologies at low energies. Phase shaping resulted in improved pulse quality. When using a bulk grating stretcher, shaping increased the autocorrelation peak by a factor of 2.9, and with a fiber stretcher, shaping increased the autocorrelation peak by a factor of 3.4. High-quality 800 fs, 65 microJ recompressed pulses were produced. This technique could benefit a wide variety of fiber amplifier systems and is self-optimising for operation at both low and high pulse energies.

  18. A 2-Micron Pulsed Integrated Path Differential Absorption Lidar Development For Atmospheric CO2 Concentration Measurements

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Petros, Mulugeta; Reithmaier, Karl; Bai, Yingxin; Trieu, Bo C.; Refaat, Tamer F.; Kavaya, Michael J.; Singh, Upendra N.

    2012-01-01

    A 2-micron pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement.

  19. Spectral amplitude and phase measurement of ultrafast pulses using all-optical differential tomography.

    PubMed

    Londero, Pablo; Kuzucu, Onur; Gaeta, Alexander L

    2011-05-01

    We demonstrate a simple, all-optical, fiber-based method for characterizing the spectral amplitude and phase of ultrafast pulses using a differential tomographic measurement realized via four-wave mixing. The technique is applied to subpicosecond pulses in the C-band of the telecommunication spectrum. Characterization of amplified pulses and propagation through dispersive media is demonstrated and compared with autocorrelation measurements and calculated predictions. We show how our approach can be extended to larger bandwidths in similar systems, extending tomographic reconstruction of coherent fields to nearly an octave of bandwidth while maintaining a robust, waveguide-based geometry.

  20. Spectral amplitude and phase measurement of ultrafast pulses using all-optical differential tomography.

    PubMed

    Londero, Pablo; Kuzucu, Onur; Gaeta, Alexander L

    2011-05-01

    We demonstrate a simple, all-optical, fiber-based method for characterizing the spectral amplitude and phase of ultrafast pulses using a differential tomographic measurement realized via four-wave mixing. The technique is applied to subpicosecond pulses in the C-band of the telecommunication spectrum. Characterization of amplified pulses and propagation through dispersive media is demonstrated and compared with autocorrelation measurements and calculated predictions. We show how our approach can be extended to larger bandwidths in similar systems, extending tomographic reconstruction of coherent fields to nearly an octave of bandwidth while maintaining a robust, waveguide-based geometry. PMID:21540969

  1. Efficient pulse compression for LPI waveforms based on a nonparametric iterative adaptive approach

    NASA Astrophysics Data System (ADS)

    Li, Zhengzheng; Nepal, Ramesh; Zhang, Yan; Blake, WIlliam

    2015-05-01

    In order to achieve low probability-of-intercept (LPI), radar waveforms are usually long and randomly generated. Due to the randomized nature, Matched filter responses (autocorrelation) of those waveforms can have high sidelobes which would mask weaker targets near a strong target, limiting radar's ability to distinguish close-by targets. To improve resolution and reduced sidelobe contaminations, a waveform independent pulse compression filter is desired. Furthermore, the pulse compression filter needs to be able to adapt to received signal to achieve optimized performance. As many existing pulse techniques require intensive computation, real-time implementation is infeasible. This paper introduces a new adaptive pulse compression technique for LPI waveforms that is based on a nonparametric iterative adaptive approach (IAA). Due to the nonparametric nature, no parameter tuning is required for different waveforms. IAA can achieve super-resolution and sidelobe suppression in both range and Doppler domains. Also it can be extended to directly handle the matched filter (MF) output (called MF-IAA), which further reduces the computational load. The practical impact of LPI waveform operations on IAA and MF-IAA has not been carefully studied in previous work. Herein the typical LPI waveforms such as random phase coding and other non- PI waveforms are tested with both single-pulse and multi-pulse IAA processing. A realistic airborne radar simulator as well as actual measured radar data are used for the validations. It is validated that in spite of noticeable difference with different test waveforms, the IAA algorithms and its improvement can effectively achieve range-Doppler super-resolution in realistic data.

  2. Phase-sensitive optical coherence reflectometer with differential phase-shift keying of probe pulses

    SciTech Connect

    Alekseev, A E; Vdovenko, V S; Sergachev, I A; Simikin, D E; Gorshkov, B G; Potapov, V T

    2014-10-31

    We report a new method for reconstructing the signal shape of the external dynamic perturbations along the entire length of the fibre of an optical coherence reflectometer. The method proposed is based on differential phase-shift keying of a probe pulse and demodulation of scattered light by the phase diversity technique. Possibilities of the method are demonstrated experimentally. (fibre-optic sensors)

  3. Differential cyanosis and undiagnosed eisenmenger's syndrome: The importance of pulse oximetry

    PubMed Central

    Sharma, Ashima; Parasa, Sujay Kumar; Gudivada, Kiran Kumar; Gopinath, Ramachandran

    2014-01-01

    Eisenmenger's physiology has significant anesthetic implications. The symptamology, in the early course of disease can be subtle at times and missed on regular PAC. Pulse oximetry, in our patient detected differential saturations. The possibility of underlying congenital cardiac illness was assumed, rescheduling of case was debated and finally the abnormal cardiac lesions were identified in ECHO in immediate postoperative period. PMID:25886232

  4. Identifying Differential Item Functioning in Multi-Stage Computer Adaptive Testing

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Lai, Hollis; Li, Johnson

    2013-01-01

    The purpose of this study is to evaluate the performance of CATSIB (Computer Adaptive Testing-Simultaneous Item Bias Test) for detecting differential item functioning (DIF) when items in the matching and studied subtest are administered adaptively in the context of a realistic multi-stage adaptive test (MST). MST was simulated using a 4-item…

  5. Comparing Methods of Assessing Differential Item Functioning in a Computerized Adaptive Testing Environment

    ERIC Educational Resources Information Center

    Lei, Pui-Wa; Chen, Shu-Ying; Yu, Lan

    2006-01-01

    Mantel-Haenszel and SIBTEST, which have known difficulty in detecting non-unidirectional differential item functioning (DIF), have been adapted with some success for computerized adaptive testing (CAT). This study adapts logistic regression (LR) and the item-response-theory-likelihood-ratio test (IRT-LRT), capable of detecting both unidirectional…

  6. Prediction of ultrasonic pulse velocity for enhanced peat bricks using adaptive neuro-fuzzy methodology.

    PubMed

    Motamedi, Shervin; Roy, Chandrabhushan; Shamshirband, Shahaboddin; Hashim, Roslan; Petković, Dalibor; Song, Ki-Il

    2015-08-01

    Ultrasonic pulse velocity is affected by defects in material structure. This study applied soft computing techniques to predict the ultrasonic pulse velocity for various peats and cement content mixtures for several curing periods. First, this investigation constructed a process to simulate the ultrasonic pulse velocity with adaptive neuro-fuzzy inference system. Then, an ANFIS network with neurons was developed. The input and output layers consisted of four and one neurons, respectively. The four inputs were cement, peat, sand content (%) and curing period (days). The simulation results showed efficient performance of the proposed system. The ANFIS and experimental results were compared through the coefficient of determination and root-mean-square error. In conclusion, use of ANFIS network enhances prediction and generation of strength. The simulation results confirmed the effectiveness of the suggested strategies.

  7. Prediction of ultrasonic pulse velocity for enhanced peat bricks using adaptive neuro-fuzzy methodology.

    PubMed

    Motamedi, Shervin; Roy, Chandrabhushan; Shamshirband, Shahaboddin; Hashim, Roslan; Petković, Dalibor; Song, Ki-Il

    2015-08-01

    Ultrasonic pulse velocity is affected by defects in material structure. This study applied soft computing techniques to predict the ultrasonic pulse velocity for various peats and cement content mixtures for several curing periods. First, this investigation constructed a process to simulate the ultrasonic pulse velocity with adaptive neuro-fuzzy inference system. Then, an ANFIS network with neurons was developed. The input and output layers consisted of four and one neurons, respectively. The four inputs were cement, peat, sand content (%) and curing period (days). The simulation results showed efficient performance of the proposed system. The ANFIS and experimental results were compared through the coefficient of determination and root-mean-square error. In conclusion, use of ANFIS network enhances prediction and generation of strength. The simulation results confirmed the effectiveness of the suggested strategies. PMID:25957464

  8. On the ability of resonant diffraction gratings to differentiate a pulsed optical signal

    SciTech Connect

    Bykov, D. A. Doskolovich, L. L.; Soifer, V. A.

    2012-05-15

    The passage of an optical pulse through a resonant grating is considered. The conditions under which the resonant grating differentiates the envelope of the incident pulse are determined. It is shown that the necessary condition for computing the k-order derivative is the presence of k resonances in the transmission spectrum of the grating in the vicinity of the central frequency of the incident pulse. A method is described for constructing the stacked structure for computing the kth derivative on the basis of repetition of the structure for computing the first derivative. The results of numerical simulation of diffraction of the pulse from the analyzed structure for computing the first, second, and third derivative are presented.

  9. Motion-adapted pulse sequences for oriented sample (OS) solid-state NMR of biopolymers.

    PubMed

    Lu, George J; Opella, Stanley J

    2013-08-28

    One of the main applications of solid-state NMR is to study the structure and dynamics of biopolymers, such as membrane proteins, under physiological conditions where the polypeptides undergo global motions as they do in biological membranes. The effects of NMR radiofrequency irradiations on nuclear spins are strongly influenced by these motions. For example, we previously showed that the MSHOT-Pi4 pulse sequence yields spectra with resonance line widths about half of those observed using the conventional pulse sequence when applied to membrane proteins undergoing rapid uniaxial rotational diffusion in phospholipid bilayers. In contrast, the line widths were not changed in microcrystalline samples where the molecules did not undergo global motions. Here, we demonstrate experimentally and describe analytically how some Hamiltonian terms are susceptible to sample motions, and it is their removal through the critical π/2 Z-rotational symmetry that confers the "motion adapted" property to the MSHOT-Pi4 pulse sequence. This leads to the design of separated local field pulse sequence "Motion-adapted SAMPI4" and is generalized to an approach for the design of decoupling sequences whose performance is superior in the presence of molecular motions. It works by cancelling the spin interaction by explicitly averaging the reduced Wigner matrix to zero, rather than utilizing the 2π nutation to average spin interactions. This approach is applicable to both stationary and magic angle spinning solid-state NMR experiments.

  10. Transient Features in Nanosecond Pulsed Electric Fields Differentially Modulate Mitochondria and Viability

    PubMed Central

    Beebe, Stephen J.; Chen, Yeong-Jer; Sain, Nova M.; Schoenbach, Karl H.; Xiao, Shu

    2012-01-01

    It is hypothesized that high frequency components of nanosecond pulsed electric fields (nsPEFs), determined by transient pulse features, are important for maximizing electric field interactions with intracellular structures. For monopolar square wave pulses, these transient features are determined by the rapid rise and fall of the pulsed electric fields. To determine effects on mitochondria membranes and plasma membranes, N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields (0–80 kV/cm) and short (15 ns) or long (150 ns) rise and fall times. Plasma membrane effects were evaluated using Fluo-4 to determine calcium influx, the only measurable source of increases in intracellular calcium. Mitochondria membrane effects were evaluated using tetramethylrhodamine ethyl ester (TMRE) to determine mitochondria membrane potentials (ΔΨm). Single pulses with short rise and fall times caused electric field-dependent increases in calcium influx, dissipation of ΔΨm and cell death. Pulses with long rise and fall times exhibited electric field-dependent increases in calcium influx, but diminished effects on dissipation of ΔΨm and viability. Results indicate that high frequency components have significant differential impact on mitochondria membranes, which determines cell death, but lesser variances on plasma membranes, which allows calcium influxes, a primary determinant for dissipation of ΔΨm and cell death. PMID:23284682

  11. Transient features in nanosecond pulsed electric fields differentially modulate mitochondria and viability.

    PubMed

    Beebe, Stephen J; Chen, Yeong-Jer; Sain, Nova M; Schoenbach, Karl H; Xiao, Shu

    2012-01-01

    It is hypothesized that high frequency components of nanosecond pulsed electric fields (nsPEFs), determined by transient pulse features, are important for maximizing electric field interactions with intracellular structures. For monopolar square wave pulses, these transient features are determined by the rapid rise and fall of the pulsed electric fields. To determine effects on mitochondria membranes and plasma membranes, N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields (0-80 kV/cm) and short (15 ns) or long (150 ns) rise and fall times. Plasma membrane effects were evaluated using Fluo-4 to determine calcium influx, the only measurable source of increases in intracellular calcium. Mitochondria membrane effects were evaluated using tetramethylrhodamine ethyl ester (TMRE) to determine mitochondria membrane potentials (ΔΨm). Single pulses with short rise and fall times caused electric field-dependent increases in calcium influx, dissipation of ΔΨm and cell death. Pulses with long rise and fall times exhibited electric field-dependent increases in calcium influx, but diminished effects on dissipation of ΔΨm and viability. Results indicate that high frequency components have significant differential impact on mitochondria membranes, which determines cell death, but lesser variances on plasma membranes, which allows calcium influxes, a primary determinant for dissipation of ΔΨm and cell death.

  12. Differential pulse amplitude modulation for multiple-input single-output OWVLC

    NASA Astrophysics Data System (ADS)

    Yang, S. H.; Kwon, D. H.; Kim, S. J.; Son, Y. H.; Han, S. K.

    2015-01-01

    White light-emitting diodes (LEDs) are widely used for lighting due to their energy efficiency, eco-friendly, and small size than previously light sources such as incandescent, fluorescent bulbs and so on. Optical wireless visible light communication (OWVLC) based on LED merges lighting and communications in applications such as indoor lighting, traffic signals, vehicles, and underwater communications because LED can be easily modulated. However, physical bandwidth of LED is limited about several MHz by slow time constant of the phosphor and characteristics of device. Therefore, using the simplest modulation format which is non-return-zero on-off-keying (NRZ-OOK), the data rate reaches only to dozens Mbit/s. Thus, to improve the transmission capacity, optical filtering and pre-, post-equalizer are adapted. Also, high-speed wireless connectivity is implemented using spectrally efficient modulation methods: orthogonal frequency division multiplexing (OFDM) or discrete multi-tone (DMT). However, these modulation methods need additional digital signal processing such as FFT and IFFT, thus complexity of transmitter and receiver is increasing. To reduce the complexity of transmitter and receiver, we proposed a novel modulation scheme which is named differential pulse amplitude modulation. The proposed modulation scheme transmits different NRZ-OOK signals with same amplitude and unit time delay using each LED chip, respectively. The `N' parallel signals from LEDs are overlapped and directly detected at optical receiver. Received signal is demodulated by power difference between unit time slots. The proposed scheme can overcome the bandwidth limitation of LEDs and data rate can be improved according to number of LEDs without complex digital signal processing.

  13. Does local adaptation to resources explain genetic differentiation among Daphnia populations?

    PubMed

    Allen, Michael R; Thum, Ryan A; Cáceres, Carla E

    2010-08-01

    Substantial genetic differentiation is frequently observed among populations of cyclically parthenogenetic zooplankton despite their high dispersal capabilities and potential for gene flow. Local adaptation has been invoked to explain population genetic differentiation despite high dispersal, but several neutral models that account for basic life history features also predict high genetic differentiation. Here, we study genetic differentiation among four populations of Daphnia pulex in east central Illinois. As with other studies of Daphnia, we demonstrate substantial population genetic differentiation despite close geographic proximity (<50 km; mean theta = 0.22). However, we explicitly tested and failed to find evidence for, the hypothesis that local adaptation to food resources occurs in these populations. Recognizing that local adaptation can occur in traits unrelated to resources, we estimated contemporary migration rates (m) and tested for admixture to evaluate the hypothesis that observed genetic differentiation is consistent with local adaptation to other untested ecological factors. Using Bayesian assignment methods, we detected migrants in three of the four study populations including substantial evidence for successful reproduction by immigrants in one pond, allowing us to reject the hypothesis that local adaptation limits gene flow for at least this population. Thus, we suggest that local adaptation does not explain genetic differentiation among these Daphnia populations and that other factors related to extinction/colonization dynamics, a long approach to equilibrium F(ST) or substantial genetic drift due to a low number of individuals hatching from the egg bank each season may explain genetic differentiation.

  14. Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells.

    PubMed

    Kupenko, I; Strohm, C; McCammon, C; Cerantola, V; Glazyrin, K; Petitgirard, S; Vasiukov, D; Aprilis, G; Chumakov, A I; Rüffer, R; Dubrovinsky, L

    2015-11-01

    Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamond anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe3C using synchrotron Mössbauer source spectroscopy, FeCO3 using nuclear inelastic scattering, and Fe2O3 using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses. PMID:26628151

  15. Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells

    SciTech Connect

    Kupenko, I. Strohm, C.; McCammon, C.; Cerantola, V.; Petitgirard, S.; Dubrovinsky, L.; Glazyrin, K.; Vasiukov, D.; Aprilis, G.; Chumakov, A. I.; Rüffer, R.

    2015-11-15

    Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamond anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe{sub 3}C using synchrotron Mössbauer source spectroscopy, FeCO{sub 3} using nuclear inelastic scattering, and Fe{sub 2}O{sub 3} using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses.

  16. Motion-adapted pulse sequences for oriented sample (OS) solid-state NMR of biopolymers

    PubMed Central

    Lu, George J.; Opella, Stanley J.

    2013-01-01

    One of the main applications of solid-state NMR is to study the structure and dynamics of biopolymers, such as membrane proteins, under physiological conditions where the polypeptides undergo global motions as they do in biological membranes. The effects of NMR radiofrequency irradiations on nuclear spins are strongly influenced by these motions. For example, we previously showed that the MSHOT-Pi4 pulse sequence yields spectra with resonance line widths about half of those observed using the conventional pulse sequence when applied to membrane proteins undergoing rapid uniaxial rotational diffusion in phospholipid bilayers. In contrast, the line widths were not changed in microcrystalline samples where the molecules did not undergo global motions. Here, we demonstrate experimentally and describe analytically how some Hamiltonian terms are susceptible to sample motions, and it is their removal through the critical π/2 Z-rotational symmetry that confers the “motion adapted” property to the MSHOT-Pi4 pulse sequence. This leads to the design of separated local field pulse sequence “Motion-adapted SAMPI4” and is generalized to an approach for the design of decoupling sequences whose performance is superior in the presence of molecular motions. It works by cancelling the spin interaction by explicitly averaging the reduced Wigner matrix to zero, rather than utilizing the 2π nutation to average spin interactions. This approach is applicable to both stationary and magic angle spinning solid-state NMR experiments. PMID:24006989

  17. Differentially-charged and sequentially-switched square-wave pulse forming network

    DOEpatents

    North, George G. [Stockton, CA; Vogilin, George E. [Livermore, CA

    1980-04-01

    A pulse forming network for delivering a high-energy square-wave pulse to a load, including a series of inductive-capacitive sections wherein the capacitors are differentially charged higher further from the load. Each charged capacitor is isolated from adjacent sections and the load by means of a normally open switch at the output of each section. The switch between the load and the closest section to the load is closed to begin discharge of the capacitor in that section into the load. During discharge of each capacitor, the voltage thereacross falls to a predetermined potential with respect to the potential across the capacitor in the next adjacent section further from the load. When this potential is reached, it is used to close the switch in the adjacent section further from the load and thereby apply the charge in that section to the load through the adjacent section toward the load. Each successive section further from the load is sequentially switched in this manner to continuously and evenly supply energy to the load over the period of the pulse, with the differentially charged capacitors providing higher potentials away from the load to compensate for the voltage drop across the resistance of each inductor. This arrangement is low in cost and yet provides a high-energy pulse in an acceptable square-wave form.

  18. Differentially-charged and sequentially-switched square-wave pulse forming network

    DOEpatents

    North, G.G.; Vogilin, G.E.

    1980-04-01

    Disclosed is a pulse forming network for delivering a high-energy square-wave pulse to a load, including a series of inductive-capacitive sections wherein the capacitors are differentially charged higher further from the load. Each charged capacitor is isolated from adjacent sections and the load by means of a normally open switch at the output of each section. The switch between the load and the closest section to the load is closed to begin discharge of the capacitor in that section into the load. During discharge of each capacitor, the voltage thereacross falls to a predetermined potential with respect to the potential across the capacitor in the next adjacent section further from the load. When this potential is reached, it is used to close the switch in the adjacent section further from the load and thereby apply the charge in that section to the load through the adjacent section toward the load. Each successive section further from the load is sequentially switched in this manner to continuously and evenly supply energy to the load over the period of the pulse, with the differentially charged capacitors providing higher potentials away from the load to compensate for the voltage drop across the resistance of each inductor. This arrangement is low in cost and yet provides a high-energy pulse in an acceptable square-wave form. 5 figs.

  19. Adaptive pulsed laser line extraction for terrain reconstruction using a dynamic vision sensor.

    PubMed

    Brandli, Christian; Mantel, Thomas A; Hutter, Marco; Höpflinger, Markus A; Berner, Raphael; Siegwart, Roland; Delbruck, Tobi

    2013-01-01

    Mobile robots need to know the terrain in which they are moving for path planning and obstacle avoidance. This paper proposes the combination of a bio-inspired, redundancy-suppressing dynamic vision sensor (DVS) with a pulsed line laser to allow fast terrain reconstruction. A stable laser stripe extraction is achieved by exploiting the sensor's ability to capture the temporal dynamics in a scene. An adaptive temporal filter for the sensor output allows a reliable reconstruction of 3D terrain surfaces. Laser stripe extractions up to pulsing frequencies of 500 Hz were achieved using a line laser of 3 mW at a distance of 45 cm using an event-based algorithm that exploits the sparseness of the sensor output. As a proof of concept, unstructured rapid prototype terrain samples have been successfully reconstructed with an accuracy of 2 mm. PMID:24478619

  20. Adaptive pulsed laser line extraction for terrain reconstruction using a dynamic vision sensor.

    PubMed

    Brandli, Christian; Mantel, Thomas A; Hutter, Marco; Höpflinger, Markus A; Berner, Raphael; Siegwart, Roland; Delbruck, Tobi

    2013-01-01

    Mobile robots need to know the terrain in which they are moving for path planning and obstacle avoidance. This paper proposes the combination of a bio-inspired, redundancy-suppressing dynamic vision sensor (DVS) with a pulsed line laser to allow fast terrain reconstruction. A stable laser stripe extraction is achieved by exploiting the sensor's ability to capture the temporal dynamics in a scene. An adaptive temporal filter for the sensor output allows a reliable reconstruction of 3D terrain surfaces. Laser stripe extractions up to pulsing frequencies of 500 Hz were achieved using a line laser of 3 mW at a distance of 45 cm using an event-based algorithm that exploits the sparseness of the sensor output. As a proof of concept, unstructured rapid prototype terrain samples have been successfully reconstructed with an accuracy of 2 mm.

  1. Adaptive pulsed laser line extraction for terrain reconstruction using a dynamic vision sensor

    PubMed Central

    Brandli, Christian; Mantel, Thomas A.; Hutter, Marco; Höpflinger, Markus A.; Berner, Raphael; Siegwart, Roland; Delbruck, Tobi

    2014-01-01

    Mobile robots need to know the terrain in which they are moving for path planning and obstacle avoidance. This paper proposes the combination of a bio-inspired, redundancy-suppressing dynamic vision sensor (DVS) with a pulsed line laser to allow fast terrain reconstruction. A stable laser stripe extraction is achieved by exploiting the sensor's ability to capture the temporal dynamics in a scene. An adaptive temporal filter for the sensor output allows a reliable reconstruction of 3D terrain surfaces. Laser stripe extractions up to pulsing frequencies of 500 Hz were achieved using a line laser of 3 mW at a distance of 45 cm using an event-based algorithm that exploits the sparseness of the sensor output. As a proof of concept, unstructured rapid prototype terrain samples have been successfully reconstructed with an accuracy of 2 mm. PMID:24478619

  2. Effects of pulsed electromagnetic field on differentiation of HUES-17 human embryonic stem cell line.

    PubMed

    Wu, Yi-Lin; Ma, Shi-Rong; Peng, Tao; Teng, Zeng-Hui; Liang, Xiang-Yan; Guo, Guo-Zhen; Zhang, Hai-Feng; Li, Kang-Chu

    2014-08-14

    Electromagnetic fields are considered to potentially affect embryonic development, but the mechanism is still unknown. In this study, human embryonic stem cell (hESC) line HUES-17 was applied to explore the mechanism of exposure on embryonic development to pulsed electromagnetic field (PEMF) for 400 pulses at different electric field intensities and the differentiation of HUES-17 cells was observed after PEMF exposure. The expression of alkaline phosphatase (AP), stage-specific embryonic antigen-3 (SSEA-3), SSEA-4 and the mRNA level and protein level of Oct4, Sox2 and Nanog in HUES-17 cells remained unchanged after PEMF exposure at the electric field intensities of 50, 100, 200 or 400 kV/m. Four hundred pulses PEMF exposure at the electric field intensities of 50, 100, 200 or 400 kV/m did not affect the differentiation of HUES-17 cells. The reason why electromagnetic fields affect embryonic development may be due to other mechanisms rather than affecting the differentiation of embryonic stem cells.

  3. Population differentiation in Pacific salmon: local adaptation, genetic drift, or the environment?

    USGS Publications Warehouse

    Adkison, M.D.

    1995-01-01

    Morphological, behavioral, and life-history differences between Pacific salmon (Oncorhynchus spp.) populations are commonly thought to reflect local adaptation, and it is likewise common to assume that salmon populations separated by small distances are locally adapted. Two alternatives to local adaptation exist: random genetic differentiation owing to genetic drift and founder events, and genetic homogeneity among populations, in which differences reflect differential trait expression in differing environments. Population genetics theory and simulations suggest that both alternatives are possible. With selectively neutral alleles, genetic drift can result in random differentiation despite many strays per generation. Even weak selection can prevent genetic drift in stable populations; however, founder effects can result in random differentiation despite selective pressures. Overlapping generations reduce the potential for random differentiation. Genetic homogeneity can occur despite differences in selective regimes when straying rates are high. In sum, localized differences in selection should not always result in local adaptation. Local adaptation is favored when population sizes are large and stable, selection is consistent over large areas, selective diffeentials are large, and straying rates are neither too high nor too low. Consideration of alternatives to local adaptation would improve both biological research and salmon conservation efforts.

  4. Human adaptation and population differentiation in the light of ancient genomes

    PubMed Central

    Key, Felix M.; Fu, Qiaomei; Romagné, Frédéric; Lachmann, Michael; Andrés, Aida M.

    2016-01-01

    The influence of positive selection sweeps in human evolution is increasingly debated, although our ability to detect them is hampered by inherent uncertainties in the timing of past events. Ancient genomes provide snapshots of allele frequencies in the past and can help address this question. We combine modern and ancient genomic data in a simple statistic (DAnc) to time allele frequency changes, and investigate the role of drift and adaptation in population differentiation. Only 30% of the most strongly differentiated alleles between Africans and Eurasians changed in frequency during the colonization of Eurasia, but in Europe these alleles are enriched in genic and putatively functional alleles to an extent only compatible with local adaptation. Adaptive alleles—especially those associated with pigmentation—are mostly of hunter-gatherer origin, although lactose persistence arose in a haplotype present in farmers. These results provide evidence for a role of local adaptation in human population differentiation. PMID:26988143

  5. Human adaptation and population differentiation in the light of ancient genomes.

    PubMed

    Key, Felix M; Fu, Qiaomei; Romagné, Frédéric; Lachmann, Michael; Andrés, Aida M

    2016-01-01

    The influence of positive selection sweeps in human evolution is increasingly debated, although our ability to detect them is hampered by inherent uncertainties in the timing of past events. Ancient genomes provide snapshots of allele frequencies in the past and can help address this question. We combine modern and ancient genomic data in a simple statistic (DAnc) to time allele frequency changes, and investigate the role of drift and adaptation in population differentiation. Only 30% of the most strongly differentiated alleles between Africans and Eurasians changed in frequency during the colonization of Eurasia, but in Europe these alleles are enriched in genic and putatively functional alleles to an extent only compatible with local adaptation. Adaptive alleles--especially those associated with pigmentation--are mostly of hunter-gatherer origin, although lactose persistence arose in a haplotype present in farmers. These results provide evidence for a role of local adaptation in human population differentiation. PMID:26988143

  6. Human adaptation and population differentiation in the light of ancient genomes.

    PubMed

    Key, Felix M; Fu, Qiaomei; Romagné, Frédéric; Lachmann, Michael; Andrés, Aida M

    2016-03-18

    The influence of positive selection sweeps in human evolution is increasingly debated, although our ability to detect them is hampered by inherent uncertainties in the timing of past events. Ancient genomes provide snapshots of allele frequencies in the past and can help address this question. We combine modern and ancient genomic data in a simple statistic (DAnc) to time allele frequency changes, and investigate the role of drift and adaptation in population differentiation. Only 30% of the most strongly differentiated alleles between Africans and Eurasians changed in frequency during the colonization of Eurasia, but in Europe these alleles are enriched in genic and putatively functional alleles to an extent only compatible with local adaptation. Adaptive alleles--especially those associated with pigmentation--are mostly of hunter-gatherer origin, although lactose persistence arose in a haplotype present in farmers. These results provide evidence for a role of local adaptation in human population differentiation.

  7. Ipsilateral medial olivocochlear reflex adaptation of the primary-source DPOAE component measured with pulsed tones

    NASA Astrophysics Data System (ADS)

    Dalhoff, Ernst; Zelle, Dennis; Gummer, Anthony W.

    2015-12-01

    Measurement of contralateral suppression or ipsilateral adaptation of DPOAE due to the medial olivocochlear reflex (MOCR) in humans has so far been complicated by interference between the two major contributors to a DPOAE signal, namely, the nonlinear and the reflection-source components. For instance, while the MOCR has been shown to act inhibitory to the cochlear amplifier, a considerable share of the measured responses has been reported to be of the excitatory type (e.g. 22% for contralateral adaptation in [11]), and it has been shown that the magnitudes of ipsilateral adaptation as well as contralateral suppression depend on the precise frequency choice relative to the position of dips in the DPOAE fine structure [3, 8]. To separate MOCR effects on both source components, we developed a paradigm consisting of five short f2 pulses presented during a 0.35 s on-period of the f1 primary within blocks of 1.35 s length. The responses at f1 and f2 were cancelled using the primary-tone phase variation technique [13]. In 16 normal-hearing subjects, we measured MOCR-induced ipsilateral adaptation at three near-by frequencies in the DPOAE fine structure, corresponding roughly to characteristic interference states between the two major source components of a DPOAE, i.e. constructive, destructive and quadrature interference. Measurements were performed in the frequency range 1.7 ≤ f2 ≤ 2 kHz, f2/f1 = 1.2, and with moderate primary-tone levels (L2 = 45 dB SPL, L1 = 57 dB SPL). Analysis of the DPOAE time traces showed that the nonlinear component typically presents inhibitory adaptation between the 1st and the 5th pulses (median: 0.92 dB). Fitting a single exponential function to the pooled data yielded adaptation of 1.49 dB. From 26 statistically significant MOCR effects (P < 0.1) ranging between 0.29 and 2.81 dB, no excitatory response was detected. The separation of the DPOAE sources when analysing MOCR effects on ipsilateral DPOAE offers the potential of investigating

  8. Final Report: Symposium on Adaptive Methods for Partial Differential Equations

    SciTech Connect

    Pernice, Michael; Johnson, Christopher R.; Smith, Philip J.; Fogelson, Aaron

    1998-12-08

    Complex physical phenomena often include features that span a wide range of spatial and temporal scales. Accurate simulation of such phenomena can be difficult to obtain, and computations that are under-resolved can even exhibit spurious features. While it is possible to resolve small scale features by increasing the number of grid points, global grid refinement can quickly lead to problems that are intractable, even on the largest available computing facilities. These constraints are particularly severe for three dimensional problems that involve complex physics. One way to achieve the needed resolution is to refine the computational mesh locally, in only those regions where enhanced resolution is required. Adaptive solution methods concentrate computational effort in regions where it is most needed. These methods have been successfully applied to a wide variety of problems in computational science and engineering. Adaptive methods can be difficult to implement, prompting the development of tools and environments to facilitate their use. To ensure that the results of their efforts are useful, algorithm and tool developers must maintain close communication with application specialists. Conversely it remains difficult for application specialists who are unfamiliar with the methods to evaluate the trade-offs between the benefits of enhanced local resolution and the effort needed to implement an adaptive solution method.

  9. Cellular differentiation hierarchies in normal and culture-adapted human embryonic stem cells.

    PubMed

    Enver, Tariq; Soneji, Shamit; Joshi, Chirag; Brown, John; Iborra, Francisco; Orntoft, Torben; Thykjaer, Thomas; Maltby, Edna; Smith, Kath; Abu Dawud, Raed; Jones, Mark; Matin, Maryam; Gokhale, Paul; Draper, Jonathan; Andrews, Peter W

    2005-11-01

    Human embryonic stem cell (HESC) lines vary in their characteristics and behaviour not only because they are derived from genetically outbred populations, but also because they may undergo progressive adaptation upon long-term culture in vitro. Such adaptation may reflect selection of variants with altered propensity for survival and retention of an undifferentiated phenotype. Elucidating the mechanisms involved will be important for understanding normal self-renewal and commitment to differentiation and for validating the safety of HESC-based therapy. We have investigated this process of adaptation at the cellular and molecular levels through a comparison of early passage (normal) and late passage (adapted) sublines of a single HESC line, H7. To account for spontaneous differentiation that occurs in HESC cultures, we sorted cells for SSEA3, which marks undifferentiated HESC. We show that the gene expression programmes of the adapted cells partially reflected their aberrant karyotype, but also resulted from a failure in X-inactivation, emphasizing the importance in adaptation of karyotypically silent epigenetic changes. On the basis of growth potential, ability to re-initiate ES cultures and global transcription profiles, we propose a cellular differentiation hierarchy for maintenance cultures of HESC: normal SSEA3+ cells represent pluripotent stem cells. Normal SSEA3- cells have exited this compartment, but retain multilineage differentiation potential. However, adapted SSEA3+ and SSEA3- cells co-segregate within the stem cell territory, implying that adaptation reflects an alteration in the balance between self-renewal and differentiation. As this balance is also an essential feature of cancer, the mechanisms of culture adaptation may mirror those of oncogenesis and tumour progression. PMID:16159889

  10. Airborne 2-Micron Double-Pulsed Integrated Path Differential Absorption Lidar for Column CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Fay, James J.; Reithmaier, Karl

    2014-01-01

    Double-pulse 2-micron lasers have been demonstrated with energy as high as 600 millijouls and up to 10 Hz repetition rate. The two laser pulses are separated by 200 microseconds and can be tuned and locked separately. Applying double-pulse laser in DIAL system enhances the CO2 measurement capability by increasing the overlap of the sampled volume between the on-line and off-line. To avoid detection complicity, integrated path differential absorption (IPDA) lidar provides higher signal-to-noise ratio measurement compared to conventional range-resolved DIAL. Rather than weak atmospheric scattering returns, IPDA rely on the much stronger hard target returns that is best suited for airborne platforms. In addition, the IPDA technique measures the total integrated column content from the instrument to the hard target but with weighting that can be tuned by the transmitter. Therefore, the transmitter could be tuned to weight the column measurement to the surface for optimum CO2 interaction studies or up to the free troposphere for optimum transport studies. Currently, NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micron IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  11. On-Line Wavelength Calibration of Pulsed Laser for CO2 Differential Absorption LIDAR

    NASA Astrophysics Data System (ADS)

    Xiang, Chengzhi; Ma, Xin; Han, Ge; Liang, Ailin; Gong, Wei

    2016-06-01

    Differential absorption lidar (DIAL) remote sensing is a promising technology for atmospheric CO2 detection. However, stringent wavelength accuracy and stability are required in DIAL system. Accurate on-line wavelength calibration is a crucial procedure for retrieving atmospheric CO2 concentration using the DIAL, particularly when pulsed lasers are adopted in the system. Large fluctuations in the intensities of a pulsed laser pose a great challenge for accurate on-line wavelength calibration. In this paper, a wavelength calibration strategy based on multi-wavelength scanning (MWS) was proposed for accurate on-line wavelength calibration of a pulsed laser for CO2 detection. The MWS conducted segmented sampling across the CO2 absorption line with appropriate number of points and range of widths by using a tunable laser. Complete absorption line of CO2 can be obtained through a curve fitting. Then, the on-line wavelength can be easily found at the peak of the absorption line. Furthermore, another algorithm called the energy matching was introduced in the MWS to eliminate the backlash error of tunable lasers during the process of on-line wavelength calibration. Finally, a series of tests was conducted to elevate the calibration precision of MWS. Analysis of tests demonstrated that the MWS proposed in this paper could calibrate the on-line wavelength of pulsed laser accurately and steadily.

  12. Adaptive array technique for differential-phase reflectometry in QUEST

    SciTech Connect

    Idei, H. Hanada, K.; Zushi, H.; Nagata, K.; Mishra, K.; Itado, T.; Akimoto, R.; Yamamoto, M. K.

    2014-11-15

    A Phased Array Antenna (PAA) was considered as launching and receiving antennae in reflectometry to attain good directivity in its applied microwave range. A well-focused beam was obtained in a launching antenna application, and differential-phase evolution was properly measured by using a metal reflector plate in the proof-of-principle experiment at low power test facilities. Differential-phase evolution was also evaluated by using the PAA in the Q-shu University Experiment with Steady State Spherical Tokamak (QUEST). A beam-forming technique was applied in receiving phased-array antenna measurements. In the QUEST device that should be considered as a large oversized cavity, standing wave effect was significantly observed with perturbed phase evolution. A new approach using derivative of measured field on propagating wavenumber was proposed to eliminate the standing wave effect.

  13. Differential time domain method improves performance of pulsed laser ranging and three-dimensional imaging.

    PubMed

    Cao, Jie; Hao, Qun; Cheng, Yang; Peng, Yuxin; Zhang, Kaiyu; Mu, Jiaxing; Wang, Peng

    2016-01-10

    A ranging method based on the differential time domain method (DTDM) is proposed in order to improve ranging accuracy and the range of active measurement based on peak discriminator (PD). We develop mathematical models and deduce that zero-crossing sensitivity is an important factor, which affects the ranging error of DTDM. Additionally, zero-crossing sensitivity is determined by delayed time. We carried out relative experiments and obtained the smallest ranging error when delayed time is receiving pulse width. We also compare ranging, three-dimensional (3D) point clouds and depth images based on two methods under same testing conditions. The results show that DTDM is beneficial in improving performance of pulse laser ranging and 3D imaging.

  14. Development of a Pulsed 2-Micron Integrated Path Differential Absorption Lidar for CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Refaat, Tamer

    2013-01-01

    Atmospheric carbon dioxide (CO2) is an important greenhouse gas that significantly contributes to the carbon cycle and global radiation budget on Earth. Active remote sensing of CO2 is important to address several limitations that contend with passive sensors. A 2-micron double-pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This active remote sensing instrument will provide an alternate approach of measuring atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise ratio level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement. Commercial, on the shelf, components are implemented for the detection system. Instrument integration will be presented in this paper as well as a background for CO2 measurement at NASA Langley research Center

  15. Transmission errors and forward error correction in embedded differential pulse code modulation

    NASA Astrophysics Data System (ADS)

    Goodman, D. J.; Sundberg, C.-E.

    1983-11-01

    Formulas are derived for the combined effects of quantization and transmission errors on embedded Differential Pulse Code Modulation (DPCM) performance. The present analysis, which is both more general and precise than previous work on transmission errors in digital communication of analog signals, includes as its special cases the conventional DPCM and Pulse code Modulation. An SNR formula is obtained in which the effects of source characteristics and the effects of transmission characteristics are clearly distinguishable. Also given in computationally convenient form are specialized formulas applying to uncoded transmission through a random-error channel, transmission through a slowly fading channel, and transmission with all or part of the DCPM signal being protected by an error-correcting code.

  16. Differential time domain method improves performance of pulsed laser ranging and three-dimensional imaging.

    PubMed

    Cao, Jie; Hao, Qun; Cheng, Yang; Peng, Yuxin; Zhang, Kaiyu; Mu, Jiaxing; Wang, Peng

    2016-01-10

    A ranging method based on the differential time domain method (DTDM) is proposed in order to improve ranging accuracy and the range of active measurement based on peak discriminator (PD). We develop mathematical models and deduce that zero-crossing sensitivity is an important factor, which affects the ranging error of DTDM. Additionally, zero-crossing sensitivity is determined by delayed time. We carried out relative experiments and obtained the smallest ranging error when delayed time is receiving pulse width. We also compare ranging, three-dimensional (3D) point clouds and depth images based on two methods under same testing conditions. The results show that DTDM is beneficial in improving performance of pulse laser ranging and 3D imaging. PMID:26835773

  17. Determination of nitrite ion and sulfanilic and orthanilic acids by differential pulse polarography

    SciTech Connect

    Sulaiman, S.T.

    1984-11-01

    The nitrite ion can be determined with a high degree of accuracy and sensitivity by differential pulse polarography utilizing the rapid and quantitative reaction between the nitrite ion and sulfanilic acid or orthanilic acid at pH 1.5. The experimental detection limit is shown to be 8.6 X 10/sup -8/ M (as NO/sub 2//sup -/) in simple aqueous solution. The method is further used to determine concentrations of sulfanilic acid down to 4 X 10/sup -7/ M and orthanilic acid down to 1.6 X 10/sup -6/ M under optimum conditions.

  18. Non-parametric PCM to ADM conversion. [Pulse Code to Adaptive Delta Modulation

    NASA Technical Reports Server (NTRS)

    Locicero, J. L.; Schilling, D. L.

    1977-01-01

    An all-digital technique to convert pulse code modulated (PCM) signals into adaptive delta modulation (ADM) format is presented. The converter developed is shown to be independent of the statistical parameters of the encoded signal and can be constructed with only standard digital hardware. The structure of the converter is simple enough to be fabricated on a large scale integrated circuit where the advantages of reliability and cost can be optimized. A concise evaluation of this PCM to ADM translation technique is presented and several converters are simulated on a digital computer. A family of performance curves is given which displays the signal-to-noise ratio for sinusoidal test signals subjected to the conversion process, as a function of input signal power for several ratios of ADM rate to Nyquist rate.

  19. Differential adaptation of descending motor tracts in musicians.

    PubMed

    Rüber, Theodor; Lindenberg, Robert; Schlaug, Gottfried

    2015-06-01

    Between-group comparisons of musicians and nonmusicians have revealed structural brain differences and also functional differences in motor performance. In this study, we aimed to examine the relation between white matter microstructure and high-level motor skills by contrasting 2 groups of musicians with different instrument-specific motor requirements. We used diffusion tensor imaging to compare diffusivity measures of different corticospinal motor tracts of 10 keyboard players, 10 string players, and 10 nonmusicians. Additionally, the maximal tapping rates of their left and right index fingers were determined. When compared with nonmusicians, fractional anisotropy (FA) values of right-hemispheric motor tracts were significantly higher in both musician groups, whereas left-hemispheric motor tracts showed significantly higher FA values only in the keyboard players. Voxel-wise FA analysis found a group effect in white matter underlying the right motor cortex. Diffusivity measures of fibers originating in the primary motor cortex correlated with the maximal tapping rate of the contralateral index finger across all groups. The observed between-group diffusivity differences might represent an adaptation to the specific motor demands of the respective musical instrument. This is supported further by finding correlations between diffusivity measures and maximal tapping rates.

  20. Differential adaptation of descending motor tracts in musicians.

    PubMed

    Rüber, Theodor; Lindenberg, Robert; Schlaug, Gottfried

    2015-06-01

    Between-group comparisons of musicians and nonmusicians have revealed structural brain differences and also functional differences in motor performance. In this study, we aimed to examine the relation between white matter microstructure and high-level motor skills by contrasting 2 groups of musicians with different instrument-specific motor requirements. We used diffusion tensor imaging to compare diffusivity measures of different corticospinal motor tracts of 10 keyboard players, 10 string players, and 10 nonmusicians. Additionally, the maximal tapping rates of their left and right index fingers were determined. When compared with nonmusicians, fractional anisotropy (FA) values of right-hemispheric motor tracts were significantly higher in both musician groups, whereas left-hemispheric motor tracts showed significantly higher FA values only in the keyboard players. Voxel-wise FA analysis found a group effect in white matter underlying the right motor cortex. Diffusivity measures of fibers originating in the primary motor cortex correlated with the maximal tapping rate of the contralateral index finger across all groups. The observed between-group diffusivity differences might represent an adaptation to the specific motor demands of the respective musical instrument. This is supported further by finding correlations between diffusivity measures and maximal tapping rates. PMID:24363265

  1. The use of solution adaptive grids in solving partial differential equations

    NASA Technical Reports Server (NTRS)

    Anderson, D. A.; Rai, M. M.

    1982-01-01

    The grid point distribution used in solving a partial differential equation using a numerical method has a substantial influence on the quality of the solution. An adaptive grid which adjusts as the solution changes provides the best results when the number of grid points available for use during the calculation is fixed. Basic concepts used in generating and applying adaptive grids are reviewed in this paper, and examples illustrating applications of these concepts are presented.

  2. Differential viability response of prokaryotes and eukaryotes to high strength pulsed magnetic stimuli.

    PubMed

    Boda, Sunil Kumar; Ravikumar, K; Saini, Deepak K; Basu, Bikramjit

    2015-12-01

    The present study examines the efficacy of a high strength pulsed magnetic field (PMF) towards bacterial inactivation in vitro, without compromising eukaryotic cell viability. The differential response of prokaryotes [Staphylococcus aureus (MRSA), Staphylococcus epidermidis, and Escherichia coli], and eukaryotes [C2C12 mouse myoblasts and human mesenchymal stem cells, hMSCs] upon exposure to varying PMF stimuli (1-4 T, 30 pulses, 40 ms pulse duration) is investigated. Among the prokaryotes, ~60% and ~70% reduction was recorded in the survival of staphylococcal species and E. coli, respectively at 4 T PMF as evaluated by colony forming unit (CFU) analysis and flow cytometry. A 2-5 fold increase in intracellular ROS (reactive oxygen species) levels suggests oxidative stress as the key mediator in PMF induced bacterial death/injury. The 4 T PMF treated staphylococci also exhibited longer doubling times. Both TEM and fluorescence microscopy revealed compromised membranes of PMF exposed bacteria. Under similar PMF exposure conditions, no immediate cytotoxicity was recorded in C2C12 mouse myoblasts and hMSCs, which can be attributed to the robust resistance towards oxidative stress. The ion interference of iron containing bacterial proteins is invoked to analytically explain the PMF induced ROS accumulation in prokaryotes. Overall, this study establishes the potential of PMF as a bactericidal method without affecting eukaryotic viability. This non-invasive stimulation protocol coupled with antimicrobial agents can be integrated as a potential methodology for the localized treatment of prosthetic infections.

  3. Parkinson's disease differentially affects adaptation to gradual as compared to sudden visuomotor distortions.

    PubMed

    Venkatakrishnan, Anusha; Banquet, Jean P; Burnod, Yves; Contreras-vidal, José L

    2011-08-01

    Patients with Parkinson's disease (PD) have difficulties in movement adaptation to optimize performance in novel environmental contexts such as altered screen cursor-hand relationships. Prior studies have shown that the time course of the distortion differentially affects visuomotor adaptation to screen cursor rotations, suggesting separate mechanisms for gradual and sudden adaptation. Moreover, studies in human and non-human primates suggest that adaptation to sudden kinematic distortions may engage the basal ganglia, whereas adaptation to gradual kinematic distortions involves cerebellar structures. In the present studies, participants were patients with PD, who performed center-out pointing movements, using either a digitizer tablet and pen or a computer trackball, under normal or rotated screen cursor feedback conditions. The initial study tested patients with PD using a cross-over experimental design for adaptation to gradual as compared with sudden rotated hand-screen cursor relationships and revealed significant after-effects for the gradual adaptation task only. Consistent with these results, findings from a follow-up experiment using a trackball that required only small finger movements showed that patients with PD adapt better to gradual as against sudden perturbations, when compared to age-matched healthy controls. We conclude that Parkinson's disease affects adaptation to sudden visuomotor distortions but spares adaptation to gradual distortions. PMID:21414678

  4. Parkinson’s Disease Differentially Affects Adaptation to Gradual as Compared to Sudden Visuomotor Distortions

    PubMed Central

    Venkatakrishnan, Anusha; Banquet, Jean P.; Burnod, Yves; Contreras-Vidal, José L.

    2011-01-01

    Patients with Parkinson’s disease (PD) have difficulties in movement adaptation to optimize performance in novel environmental contexts such as altered screen cursor-hand relationships. Prior studies have shown that the time course of the distortion differentially affects visuomotor adaptation to screen cursor rotations, suggesting separate mechanisms for gradual and sudden adaptation. Moreover, studies in human and non-human primates suggest that adaptation to sudden kinematic distortions may engage the basal ganglia, whereas adaptation to gradual kinematic distortions involves cerebellar structures. In the present studies, participants were patients with PD, who performed center-out pointing movements, using either a digitizer tablet and pen or a computer trackball, under normal or rotated screen cursor feedback conditions. The initial study tested patients with PD using a cross-over experimental design for adaptation to gradual as compared with sudden rotated hand-screen cursor relationships and revealed significant after-effects for the gradual adaptation task only. Consistent with these results, findings from a follow-up experiment using a trackball that required only small finger movements showed that patients with PD adapt better to gradual as against sudden perturbations, when compared to age-matched healthy controls. We conclude that Parkinson’s disease affects adaptation to sudden visuomotor distortions but spares adaptation to gradual distortions. PMID:21414678

  5. Parkinson's disease differentially affects adaptation to gradual as compared to sudden visuomotor distortions.

    PubMed

    Venkatakrishnan, Anusha; Banquet, Jean P; Burnod, Yves; Contreras-vidal, José L

    2011-08-01

    Patients with Parkinson's disease (PD) have difficulties in movement adaptation to optimize performance in novel environmental contexts such as altered screen cursor-hand relationships. Prior studies have shown that the time course of the distortion differentially affects visuomotor adaptation to screen cursor rotations, suggesting separate mechanisms for gradual and sudden adaptation. Moreover, studies in human and non-human primates suggest that adaptation to sudden kinematic distortions may engage the basal ganglia, whereas adaptation to gradual kinematic distortions involves cerebellar structures. In the present studies, participants were patients with PD, who performed center-out pointing movements, using either a digitizer tablet and pen or a computer trackball, under normal or rotated screen cursor feedback conditions. The initial study tested patients with PD using a cross-over experimental design for adaptation to gradual as compared with sudden rotated hand-screen cursor relationships and revealed significant after-effects for the gradual adaptation task only. Consistent with these results, findings from a follow-up experiment using a trackball that required only small finger movements showed that patients with PD adapt better to gradual as against sudden perturbations, when compared to age-matched healthy controls. We conclude that Parkinson's disease affects adaptation to sudden visuomotor distortions but spares adaptation to gradual distortions.

  6. Adaptive differentiation of traits related to resource use in a desert annual along a resource gradient.

    PubMed

    Brouillette, Larry C; Mason, Chase M; Shirk, Rebecca Y; Donovan, Lisa A

    2014-03-01

    • Plant resource-use traits are generally hypothesized to be adaptively differentiated for populations distributed along resource gradients. Although nutrient limitations are expected to select for resource-conservative strategies, water limitations may select for either resource-conservative or -acquisitive strategies. We test whether population differentiation reflects local adaptation for traits associated with resource-use strategies in a desert annual (Helianthus anomalus) distributed along a gradient of positively covarying water and nutrient availability. • We compared quantitative trait variation (Q(ST)) with neutral genetic differentiation (F(ST)), in a common garden glasshouse study, for leaf economics spectrum (LES) and related traits: photosynthesis (A(mass), A(area)), leaf nitrogen (N(mass), N(area)), leaf lifetime (LL), leaf mass per area (LMA), leaf water content (LWC), water-use efficiency (WUE, estimated as δ(13)C) and days to first flower (DFF). • Q(ST)-F(ST) differences support adaptive differentiation for Amass , N(mass), N(area), LWC and DFF. The trait combinations associated with drier and lower fertility sites represent correlated trait evolution consistent with the more resource-acquisitive end of the LES. There was no evidence for adaptive differentiation for A(area), LMA and WUE. • These results demonstrate that hot dry environments can selectively favor correlated evolution of traits contributing to a resource-acquisitive and earlier reproduction 'escape' strategy, despite lower fertility.

  7. Adaptive Failure Compensation for Aircraft Tracking Control Using Engine Differential Based Model

    NASA Technical Reports Server (NTRS)

    Liu, Yu; Tang, Xidong; Tao, Gang; Joshi, Suresh M.

    2006-01-01

    An aircraft model that incorporates independently adjustable engine throttles and ailerons is employed to develop an adaptive control scheme in the presence of actuator failures. This model captures the key features of aircraft flight dynamics when in the engine differential mode. Based on this model an adaptive feedback control scheme for asymptotic state tracking is developed and applied to a transport aircraft model in the presence of two types of failures during operation, rudder failure and aileron failure. Simulation results are presented to demonstrate the adaptive failure compensation scheme.

  8. Enhanced responsiveness to parathyroid hormone and induction of functional differentiation of cultured rabbit costal chondrocytes by a pulsed electromagnetic field.

    PubMed

    Hiraki, Y; Endo, N; Takigawa, M; Asada, A; Takahashi, H; Suzuki, F

    1987-10-22

    Pulsed electromagnetic fields promote healing of delayed united and ununited fractures by triggering a series of events in fibrocartilage. We examined the effects of a pulsed electromagnetic field (recurrent bursts, 15.4 Hz, of shorter pulses of an average of 2 gauss) on rabbit costal chondrocytes in culture. A pulsed electromagnetic field slightly reduced the intracellular cyclic adenosine 3',5'-monophosphate (cAMP) level in the culture. However, it significantly enhanced cAMP accumulation in response to parathyroid hormone (PTH) to 140% of that induced by PTH in its absence, while it did not affect cAMP accumulation in response to prostaglandin E1 or prostaglandin I2. The effect on cAMP accumulation in response to PTH became evident after exposure of the cultures to the pulsed electromagnetic field for 48 h, and was dependent upon the field strength. cAMP accumulation in response to PTH is followed by induction of ornithine decarboxylase, a good marker of differentiated chondrocytes, after PTH treatment for 4 h. Consistent with the enhanced cAMP accumulation, ornithine decarboxylase activity induced by PTH was also increased by the pulsed electromagnetic field to 170% of that in cells not exposed to a pulsed electromagnetic field. Furthermore, stimulation of glycosaminoglycan synthesis, a differentiated phenotype, in response to PTH was significantly enhanced by a pulsed electromagnetic field. Thus, a pulsed electromagnetic field enhanced a series of events in rabbit costal chondrocytes in response to PTH. These findings show that exposure of chondrocytes to a pulsed electromagnetic field resulted in functional differentiation of the cells.

  9. Femtosecond laser pulses for chemical-free embryonic and mesenchymal stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Mthunzi, Patience; Dholakia, Kishan; Gunn-Moore, Frank

    2011-10-01

    Owing to their self renewal and pluripotency properties, stem cells can efficiently advance current therapies in tissue regeneration and/or engineering. Under appropriate culture conditions in vitro, pluripotent stem cells can be primed to differentiate into any cell type some examples including neural, cardiac and blood cells. However, there still remains a pressing necessity to answer the biological questions concerning how stem cell renewal and how differentiation programs are operated and regulated at the genetic level. In stem cell research, an urgent requirement on experimental procedures allowing non-invasive, marker-free observation of growth, proliferation and stability of living stem cells under physiological conditions exists. Femtosecond (fs) laser pulses have been reported to non-invasively deliver exogenous materials, including foreign genetic species into both multipotent and pluripotent stem cells successfully. Through this multi-photon facilitated technique, directly administering fs laser pulses onto the cell plasma membrane induces transient submicrometer holes, thereby promoting cytosolic uptake of the surrounding extracellular matter. To display a chemical-free cell transfection procedure that utilises micro-litre scale volumes of reagents, we report for the first time on 70 % transfection efficiency in ES-E14TG2a cells using the enhanced green fluorescing protein (EGFP) DNA plasmid. We also show how varying the average power output during optical transfection influences cell viability, proliferation and cytotoxicity in embryonic stem cells. The impact of utilizing objective lenses of different numerical aperture (NA) on the optical transfection efficiency in ES-E14TG2a cells is presented. Finally, we report on embryonic and mesenchymal stem cell differentiation. The produced specialized cell types could thereafter be characterized and used for cell based therapies.

  10. Role of phenotypic plasticity and population differentiation in adaptation to novel environmental conditions

    PubMed Central

    Volis, Sergei; Ormanbekova, Danara; Yermekbayev, Kanat

    2015-01-01

    Species can adapt to new environmental conditions either through individual phenotypic plasticity, intraspecific genetic differentiation in adaptive traits, or both. Wild emmer wheat, Triticum dicoccoides, an annual grass with major distribution in Eastern Mediterranean region, is predicted to experience in the near future, as a result of global climate change, conditions more arid than in any part of the current species distribution. To understand the role of the above two means of adaptation, and the effect of population range position, we analyzed reaction norms, extent of plasticity, and phenotypic selection across two experimental environments of high and low water availability in two core and two peripheral populations of this species. We studied 12 quantitative traits, but focused primarily on the onset of reproduction and maternal investment, which are traits that are closely related to fitness and presumably involved in local adaptation in the studied species. We hypothesized that the population showing superior performance under novel environmental conditions will either be genetically differentiated in quantitative traits or exhibit higher phenotypic plasticity than the less successful populations. We found the core population K to be the most plastic in all three trait categories (phenology, reproductive traits, and fitness) and most successful among populations studied, in both experimental environments; at the same time, the core K population was clearly genetically differentiated from the two edge populations. Our results suggest that (1) two means of successful adaptation to new environmental conditions, phenotypic plasticity and adaptive genetic differentiation, are not mutually exclusive ways of achieving high adaptive ability; and (2) colonists from some core populations can be more successful in establishing beyond the current species range than colonists from the range extreme periphery with conditions seemingly closest to those in the new

  11. Role of phenotypic plasticity and population differentiation in adaptation to novel environmental conditions.

    PubMed

    Volis, Sergei; Ormanbekova, Danara; Yermekbayev, Kanat

    2015-09-01

    Species can adapt to new environmental conditions either through individual phenotypic plasticity, intraspecific genetic differentiation in adaptive traits, or both. Wild emmer wheat, Triticum dicoccoides, an annual grass with major distribution in Eastern Mediterranean region, is predicted to experience in the near future, as a result of global climate change, conditions more arid than in any part of the current species distribution. To understand the role of the above two means of adaptation, and the effect of population range position, we analyzed reaction norms, extent of plasticity, and phenotypic selection across two experimental environments of high and low water availability in two core and two peripheral populations of this species. We studied 12 quantitative traits, but focused primarily on the onset of reproduction and maternal investment, which are traits that are closely related to fitness and presumably involved in local adaptation in the studied species. We hypothesized that the population showing superior performance under novel environmental conditions will either be genetically differentiated in quantitative traits or exhibit higher phenotypic plasticity than the less successful populations. We found the core population K to be the most plastic in all three trait categories (phenology, reproductive traits, and fitness) and most successful among populations studied, in both experimental environments; at the same time, the core K population was clearly genetically differentiated from the two edge populations. Our results suggest that (1) two means of successful adaptation to new environmental conditions, phenotypic plasticity and adaptive genetic differentiation, are not mutually exclusive ways of achieving high adaptive ability; and (2) colonists from some core populations can be more successful in establishing beyond the current species range than colonists from the range extreme periphery with conditions seemingly closest to those in the new

  12. Adaptive Kalman-Bucy filter for differential absorption lidar time series data.

    PubMed

    Warren, R E

    1987-11-15

    An extension of the Kalman-Bucy algorithm for on-line estimation of multimaterial path-integrated concentration from multiwavelength differential absorption lidar time series data is presented in which the system model covariance is adaptively estimated from the input data. Performance of the filter is compared with that of a nonadaptive Kalman-Bucy filter using synthetic and actual lidar data.

  13. Pulse

    MedlinePlus

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the patient's heart is pumping. ... rate gives information about your fitness level and health.

  14. Genomewide scan for adaptive differentiation along altitudinal gradient in the Andrew's toad Bufo andrewsi.

    PubMed

    Guo, Baocheng; Lu, Di; Liao, Wen Bo; Merilä, Juha

    2016-08-01

    Recent studies of humans, dogs and rodents have started to discover the genetic underpinnings of high altitude adaptations, yet amphibians have received little attention in this respect. To identify possible signatures of adaptation to altitude, we performed a genome scan of 15 557 single nucleotide polymorphisms (SNPs) obtained with restriction site-associated DNA sequencing of pooled samples from 11 populations of Andrew's toad (Bufo andrewsi) from the edge of the Tibetan Plateau, spanning an altitudinal gradient from 1690 to 2768 m.a.s.l. We discovered significant geographic differentiation among all sites, with an average FST   = 0.023 across all SNPs. Apart from clear patterns of isolation by distance, we discovered numerous outlier SNPs showing strong associations with variation in altitude (1394 SNPs), average annual temperature (1859 SNPs) or both (1051 SNPs). Levels and patterns of genetic differentiation in these SNPs were consistent with the hypothesis that they have been subject to directional selection and reflect adaptation to altitudinal variation among the study sites. Genes with footprints of selection were significantly enriched in binding and metabolic processes. Several genes potentially related to high altitude adaptation were identified, although the identity and functional significance of most genomic targets of selection remain unknown. In general, the results provide genomic support for results of earlier common garden and low coverage genetic studies that have uncovered substantial adaptive differentiation along altitudinal and latitudinal gradients in amphibians. PMID:27289071

  15. Adaptive Failure Compensation for Aircraft Flight Control Using Engine Differentials: Regulation

    NASA Technical Reports Server (NTRS)

    Yu, Liu; Xidong, Tang; Gang, Tao; Joshi, Suresh M.

    2005-01-01

    The problem of using engine thrust differentials to compensate for rudder and aileron failures in aircraft flight control is addressed in this paper in a new framework. A nonlinear aircraft model that incorporates engine di erentials in the dynamic equations is employed and linearized to describe the aircraft s longitudinal and lateral motion. In this model two engine thrusts of an aircraft can be adjusted independently so as to provide the control flexibility for rudder or aileron failure compensation. A direct adaptive compensation scheme for asymptotic regulation is developed to handle uncertain actuator failures in the linearized system. A design condition is specified to characterize the system redundancy needed for failure compensation. The adaptive regulation control scheme is applied to the linearized model of a large transport aircraft in which the longitudinal and lateral motions are coupled as the result of using engine thrust differentials. Simulation results are presented to demonstrate the effectiveness of the adaptive compensation scheme.

  16. 2 cm spatial-resolution and 2 km range Brillouin optical fiber sensor using a transient differential pulse pair.

    PubMed

    Dong, Yongkang; Zhang, Hongying; Chen, Liang; Bao, Xiaoyi

    2012-03-20

    We report a high-spatial-resolution and long-range distributed temperature sensor through optimizing differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA). In DPP-BOTDA, the differential signal suffers from a signal-to-noise ratio (SNR) reduction with respect to the original signals, and for a fixed pulse-width difference the SNR reduction increases with the pulse width. Through reducing the pulse width to a transient regime (near to or less than the phonon lifetime) to decrease the SNR reduction after the differential process, the optimized 8/8.2 ns pulse pair is applied to realize a 2 cm spatial resolution, where a pulse generator with a 150 ps fall-time is used to ensure the effective resolution of DPP-BOTDA. In the experiment, a 2 cm spatial-resolution hot-spot detection with a 2 °C temperature accuracy is demonstrated over a 2 km sensing fiber. PMID:22441465

  17. Simultaneous determination of three herbicides by differential pulse voltammetry and chemometrics.

    PubMed

    Ni, Yongnian; Wang, Lin; Kokot, Serge

    2011-01-01

    A novel differential pulse voltammetry method (DPV) was researched and developed for the simultaneous determination of Pendimethalin, Dinoseb and sodium 5-nitroguaiacolate (5NG) with the aid of chemometrics. The voltammograms of these three compounds overlapped significantly, and to facilitate the simultaneous determination of the three analytes, chemometrics methods were applied. These included classical least squares (CLS), principal component regression (PCR), partial least squares (PLS) and radial basis function-artificial neural networks (RBF-ANN). A separately prepared verification data set was used to confirm the calibrations, which were built from the original and first derivative data matrices of the voltammograms. On the basis relative prediction errors and recoveries of the analytes, the RBF-ANN and the DPLS (D - first derivative spectra) models performed best and are particularly recommended for application. The DPLS calibration model was applied satisfactorily for the prediction of the three analytes from market vegetables and lake water samples. PMID:21512931

  18. Phototransfection of mammalian cells using femtosecond laser pulses: optimization and applicability to stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Mthunzi, Patience; Dholakia, Kishan; Gunn-Moore, Frank

    2010-07-01

    Recently, femtosecond laser pulses have been utilized for the targeted introduction of genetic matter into mammalian cells. This rapidly expanding and developing novel optical technique using a tightly focused laser light beam is called phototransfection. Extending previous studies [Stevenson et al., Opt. Express 14, 7125-7133 (2006)], we show that femtosecond lasers can be used to phototransfect a range of different cell lines, and specifically that this novel technology can also transfect mouse embryonic stem cell colonies with ~25% efficiency. Notably, we show the ability of differentiating these cells into the extraembryonic endoderm using phototransfection. Furthermore, we present two new findings aimed at optimizing the phototransfection method and improving applicability: first, the influence of the cell passage number on the transfection efficiency is explored and, second, the ability to enhance the transfection efficiency via whole culture treatments. Our results should encourage wider uptake of this methodology.

  19. Determination of antioxidant activity of spices and their active principles by differential pulse voltammetry.

    PubMed

    Palma, Alberto; Ruiz Montoya, Mercedes; Arteaga, Jesús F; Rodríguez Mellado, Jose M

    2014-01-22

    The anodic oxidation of mercury in the presence of hydrogen peroxide in differential pulse voltammetry (DPV) was used to determine the antioxidant (AO) character of radical scavengers. Hydroperoxide radical is formed at the potentials of the oxidation peak on mercury electrodes, such radical reacting with the antioxidants in different extension. The parameter C10 (antioxidant concentration at which the peak area decreases by 10%) is used to measure the scavenging activity of the individual antioxidants. To establish the scavenging activity of antioxidant mixtures as a whole, the parameter, μ10 as the reverse of V10, V10 being the volume necessary to decrease the peak area in DPV by 10%, was selected. Higher μ10 values correspond to higher scavenging activity. The studies have been extended to aqueous extracts of some species. The results may be useful in explaining the effect of spices in vitro and in vivo studies.

  20. Determination of trimebutine in pharmaceuticals by differential pulse voltammetry at a glassy carbon electrode.

    PubMed

    Adhoum, Nafaâ; Monser, Lotfi

    2005-07-15

    The differential pulse voltammetric (DPV) determination of trimebutine (TMB) was achieved at a glassy carbon electrode in acetonitrile/0.1 M LiClO4. Trimebutine gave two irreversible, diffusion controlled peaks at 740 and 1318 mV versus Ag/AgCl reference electrode, respectively. The second oxidation peak was used to determine trimebutine concentrations in the range 1-50 microg ml(-1) with a detection limit (3sigmam) of 0.3 microg ml(-1). Precision of the method (RSD, n=6) within- and between-days obtained from six determinations at 5 microg ml(-1) was found to be 0.7 and 1.1%, respectively. The method was successfully applied to the quantitation of TMB in granule dosage form (Debridat) and recoveries between 98.4 and 101% were obtained. Excipients did not interfere with the assay and the results agreed well with those determined by previously established HPLC method. PMID:15967289

  1. Indirect differential pulse voltammetric determination of aluminum by a pyrocatechol violet-modified electrode

    SciTech Connect

    Chen, G.; Bi, S.; Dai, L.; Cao, M.; Chen, Y. Wang, X.

    1999-03-01

    Aluminum is one of the abundant elements in the earth`s crust. It has been considered to be a causative agent for various neurological disorders such as Alzheimer Senile, presenile dementia and amyotrophic lateral sclerosis. It is also very harmful to plants and aquatic organisms. Therefore, the determination of Al is very important. A Pyrocatechol Violet (PCV) modified electrode for the voltammetric determination of aluminum is reported. The modified electrode is simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. Optimum experimental conditions for aluminum determination include a 0.2 mol/L NaAc-HAc buffer solution of pH 4.8, a PCV concentration of 0.02 mol/L used to modify the electrode and the use of differential-pulse mode for measurement. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al into the buffer solution while the peak potentials remain the same. The decreasing value of peak current {Delta}i{sub p} is linear with Al concentration in the range of 1{times}10{sup {minus}8} to 1{times}10{sup {minus}7} mol/L and 1{times}10{sup {minus}7} to 1{times}10{sup {minus}6} mol/L. The detection limit is 5{times}10{sup {minus}9} mol/L and the relative standard deviation for 4{times}10{sup {minus}8} mol/L Al is 2.9% (n=8). The stability of this electrode is satisfactory. No serious interference is found. This method has been applied to determine Al in drinking water samples.

  2. Differential polarization nonlinear optical microscopy with adaptive optics controlled multiplexed beams.

    PubMed

    Samim, Masood; Sandkuijl, Daaf; Tretyakov, Ian; Cisek, Richard; Barzda, Virginijus

    2013-01-01

    Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved with microscopic spatial resolution by using time-multiplexed pulsed laser beams with perpendicular polarization orientations and photon-counting detection electronics for signal demultiplexing. In addition, deformable membrane mirrors can be used to correct for optical aberrations in the microscope and simultaneously optimize beam overlap using a genetic algorithm. The beam overlap can be achieved with better accuracy than diffraction limited point-spread function, which allows to perform polarization-resolved measurements on the pixel-by-pixel basis. We describe a newly developed differential polarization microscope and present applications of the differential microscopy technique for structural studies of collagen and cellulose. Both, second harmonic generation, and fluorescence-detected nonlinear absorption anisotropy are used in these investigations. It is shown that the orientation and structural properties of the fibers in biological tissue can be deduced and that the orientation of fluorescent molecules (Congo Red), which label the fibers, can be determined. Differential polarization microscopy sidesteps common issues such as photobleaching and sample movement. Due to tens of megahertz alternating polarization of excitation pulses fast data acquisition can be conveniently applied to measure changes in the nonlinear signal anisotropy in dynamically changing in vivo structures.

  3. Epigenetic differentiation and relationship to adaptive genetic divergence in discrete populations of the violet Viola cazorlensis.

    PubMed

    Herrera, Carlos M; Bazaga, Pilar

    2010-08-01

    *In plants, epigenetic variations based on DNA methylation are often heritable and could influence the course of evolution. Before this hypothesis can be assessed, fundamental questions about epigenetic variation remain to be addressed in a real-world context, including its magnitude, structuring within and among natural populations, and autonomy in relation to the genetic context. *Extent and patterns of cytosine methylation, and the relationship to adaptive genetic divergence between populations, were investigated for wild populations of the southern Spanish violet Viola cazorlensis (Violaceae) using the methylation-sensitive amplified polymorphism (MSAP) technique, a modification of the amplified fragment length polymorphism method (AFLP) based on the differential sensitivity of isoschizomeric restriction enzymes to site-specific cytosine methylation. *The genome of V. cazorlensis plants exhibited extensive levels of methylation, and methylation-based epigenetic variation was structured into distinct between- and within- population components. Epigenetic differentiation of populations was correlated with adaptive genetic divergence revealed by a Bayesian population-genomic analysis of AFLP data. Significant associations existed at the individual genome level between adaptive AFLP loci and the methylation state of methylation-susceptible MSAP loci. *Population-specific, divergent patterns of correlated selection on epigenetic and genetic individual variation could account for the coordinated epigenetic-genetic adaptive population differentiation revealed by this study.

  4. What can patterns of differentiation across plant genomes tell us about adaptation and speciation?

    PubMed Central

    Strasburg, Jared L.; Sherman, Natasha A.; Wright, Kevin M.; Moyle, Leonie C.; Willis, John H.; Rieseberg, Loren H.

    2012-01-01

    Genome scans have become a common approach to identify genomic signatures of natural selection and reproductive isolation, as well as the genomic bases of ecologically relevant phenotypes, based on patterns of polymorphism and differentiation among populations or species. Here, we review the results of studies taking genome scan approaches in plants, consider the patterns of genomic differentiation documented and their possible causes, discuss the results in light of recent models of genomic differentiation during divergent adaptation and speciation, and consider assumptions and caveats in their interpretation. We find that genomic regions of high divergence generally appear quite small in comparisons of both closely and more distantly related populations, and for the most part, these differentiated regions are spread throughout the genome rather than strongly clustered. Thus, the genome scan approach appears well-suited for identifying genomic regions or even candidate genes that underlie adaptive divergence and/or reproductive barriers. We consider other methodologies that may be used in conjunction with genome scan approaches, and suggest further developments that would be valuable. These include broader use of sequence-based markers of known genomic location, greater attention to sampling strategies to make use of parallel environmental or phenotypic transitions, more integration with approaches such as quantitative trait loci mapping and measures of gene flow across the genome, and additional theoretical and simulation work on processes related to divergent adaptation and speciation. PMID:22201166

  5. Life history trait differentiation and local adaptation in invasive populations of Ambrosia artemisiifolia in China.

    PubMed

    Li, Xiao-Meng; She, Deng-Ying; Zhang, Da-Yong; Liao, Wan-Jin

    2015-03-01

    Local adaptation has been suggested to play an important role in range expansion, particularly among invasive species. However, the extent to which local adaptation affects the success of an invasive species and the factors that contribute to local adaptation are still unclear. This study aimed to investigate a case of population divergence that may have contributed to the local adaptation of invasive populations of Ambrosia artemisiifolia in China. Common garden experiments in seven populations indicated clinal variations along latitudinal gradients, with plants from higher latitudes exhibiting earlier flowering and smaller sizes at flowering. In reciprocal transplant experiments, plants of a northern Beijing origin produced more seeds at their home site than plants of a southern Wuhan origin, and the Wuhan-origin plants had grown taller at flowering than the Beijing-origin plants in Wuhan, which is believed to facilitate pollen dispersal. These results suggest that plants of Beijing origin may be locally adapted through female fitness and plants from Wuhan possibly locally adapted through male fitness. Selection and path analysis suggested that the phenological and growth traits of both populations have been influenced by natural selection and that flowering time has played an important role through its direct and indirect effects on the relative fitness of each individual. This study evidences the life history trait differentiation and local adaptation during range expansion of invasive A. artemisiifolia in China.

  6. Boundedness of the solutions for certain classes of fractional differential equations with application to adaptive systems.

    PubMed

    Aguila-Camacho, Norelys; Duarte-Mermoud, Manuel A

    2016-01-01

    This paper presents the analysis of three classes of fractional differential equations appearing in the field of fractional adaptive systems, for the case when the fractional order is in the interval α ∈(0,1] and the Caputo definition for fractional derivatives is used. The boundedness of the solutions is proved for all three cases, and the convergence to zero of the mean value of one of the variables is also proved. Applications of the obtained results to fractional adaptive schemes in the context of identification and control problems are presented at the end of the paper, including numerical simulations which support the analytical results.

  7. Differentially Private Histogram Publication For Dynamic Datasets: An Adaptive Sampling Approach

    PubMed Central

    Li, Haoran; Jiang, Xiaoqian; Xiong, Li; Liu, Jinfei

    2016-01-01

    Differential privacy has recently become a de facto standard for private statistical data release. Many algorithms have been proposed to generate differentially private histograms or synthetic data. However, most of them focus on “one-time” release of a static dataset and do not adequately address the increasing need of releasing series of dynamic datasets in real time. A straightforward application of existing histogram methods on each snapshot of such dynamic datasets will incur high accumulated error due to the composibility of differential privacy and correlations or overlapping users between the snapshots. In this paper, we address the problem of releasing series of dynamic datasets in real time with differential privacy, using a novel adaptive distance-based sampling approach. Our first method, DSFT, uses a fixed distance threshold and releases a differentially private histogram only when the current snapshot is sufficiently different from the previous one, i.e., with a distance greater than a predefined threshold. Our second method, DSAT, further improves DSFT and uses a dynamic threshold adaptively adjusted by a feedback control mechanism to capture the data dynamics. Extensive experiments on real and synthetic datasets demonstrate that our approach achieves better utility than baseline methods and existing state-of-the-art methods. PMID:26973795

  8. Low-intensity pulsed ultrasound regulates proliferation and differentiation of osteoblasts through osteocytes

    SciTech Connect

    Li, Lei; Yang, Zheng; Zhang, Hai; Chen, Wenchuan; Chen, Mengshi; Zhu, Zhimin

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer CM from LIPUS-stimulated osteocytes inhibits proliferation of osteoblasts. Black-Right-Pointing-Pointer CM from LIPUS-stimulated osteocytes enhances differentiation of osteoblasts. Black-Right-Pointing-Pointer LIPUS stimulates MLO-Y4 cells to secrete PGE{sub 2} and NO. -- Abstract: Low-intensity pulsed ultrasound (LIPUS) has been used as a safe and effective modality to enhance fracture healing. As the most abundant cells in bone, osteocytes orchestrate biological activities of effector cells via direct cell-to-cell contacts and by soluble factors. In this study, we have used the osteocytic MLO-Y4 cells to study the effects of conditioned medium from LIPUS-stimulated MLO-Y4 cells on proliferation and differentiation of osteoblastic MC3T3-E1 cells. Conditioned media from LIPUS-stimulated MLO-Y4 cells (LIPUS-Osteocyte-CM) were collected and added on MC3T3-E1 cell cultures. MC3T3-E1 cells cultured in LIPUS-Osteocyte-CM demonstrated a significant inhibition of proliferation and an increased alkaline phosphatase activity. The results of PGE{sub 2} and NO assay showed that LIPUS could enhance PGE{sub 2} and NO secretion from MLO-Y4 cells at all time points within 24 h after LIPUS stimulation. We conclude that LIPUS regulates proliferation and differentiation of osteoblasts through osteocytes in vitro. Increased secretion of PGE{sub 2} from osteocytes may play a role in this effect.

  9. PULSE HEIGHT ANALYZER

    DOEpatents

    Goldsworthy, W.W.

    1958-06-01

    A differential pulse-height discriminator circuit is described which is readily adaptable for operation in a single-channel pulse-height analyzer. The novel aspect of the circuit lies in the specific arrangement of differential pulse-height discriminator which includes two pulse-height discriminators having a comnnon input and an anticoincidence circuit having two interconnected vacuum tubes with a common cathode resistor. Pulses from the output of one discriminator circuit are delayed and coupled to the grid of one of the anticoincidence tubes by a resistor. The output pulses from the other discriminator circuit are coupled through a cathode follower circuit, which has a cathode resistor of such value as to provide a long time constant with the interelectrode capacitance of the tube, to lenthen the output pulses. The pulses are then fed to the grid of the other anticoincidence tube. With such connections of the circuits, only when the incoming pulse has a pesk value between the operating levels of the two discriminators does an output pulse occur from the anticoincidence circuit.

  10. Mapping Activity Variations for Ru2O3 in Lunar Volcanic Green Glass Analogs Using Differential Pulse Voltammetry

    NASA Technical Reports Server (NTRS)

    Malum, K. M.; Colson, R. O.; Sawarynski, M.

    2001-01-01

    Using differential pulse voltammetry, we are mapping variations in activities for NiO and Ru2O3 as a function of compositional variation for compositions centered around an Apollo 15 green glass analog. Additional information is contained in the original extended abstract.

  11. Contemporary evolution during invasion: evidence for differentiation, natural selection, and local adaptation.

    PubMed

    Colautti, Robert I; Lau, Jennifer A

    2015-05-01

    Biological invasions are 'natural' experiments that can improve our understanding of contemporary evolution. We evaluate evidence for population differentiation, natural selection and adaptive evolution of invading plants and animals at two nested spatial scales: (i) among introduced populations (ii) between native and introduced genotypes. Evolution during invasion is frequently inferred, but rarely confirmed as adaptive. In common garden studies, quantitative trait differentiation is only marginally lower (~3.5%) among introduced relative to native populations, despite genetic bottlenecks and shorter timescales (i.e. millennia vs. decades). However, differentiation between genotypes from the native vs. introduced range is less clear and confounded by nonrandom geographic sampling; simulations suggest this causes a high false-positive discovery rate (>50%) in geographically structured populations. Selection differentials (¦s¦) are stronger in introduced than in native species, although selection gradients (¦β¦) are not, consistent with introduced species experiencing weaker genetic constraints. This could facilitate rapid adaptation, but evidence is limited. For example, rapid phenotypic evolution often manifests as geographical clines, but simulations demonstrate that nonadaptive trait clines can evolve frequently during colonization (~two-thirds of simulations). Additionally, QST-FST studies may often misrepresent the strength and form of natural selection acting during invasion. Instead, classic approaches in evolutionary ecology (e.g. selection analysis, reciprocal transplant, artificial selection) are necessary to determine the frequency of adaptive evolution during invasion and its influence on establishment, spread and impact of invasive species. These studies are rare but crucial for managing biological invasions in the context of global change. PMID:25891044

  12. Contemporary evolution during invasion: evidence for differentiation, natural selection, and local adaptation.

    PubMed

    Colautti, Robert I; Lau, Jennifer A

    2015-05-01

    Biological invasions are 'natural' experiments that can improve our understanding of contemporary evolution. We evaluate evidence for population differentiation, natural selection and adaptive evolution of invading plants and animals at two nested spatial scales: (i) among introduced populations (ii) between native and introduced genotypes. Evolution during invasion is frequently inferred, but rarely confirmed as adaptive. In common garden studies, quantitative trait differentiation is only marginally lower (~3.5%) among introduced relative to native populations, despite genetic bottlenecks and shorter timescales (i.e. millennia vs. decades). However, differentiation between genotypes from the native vs. introduced range is less clear and confounded by nonrandom geographic sampling; simulations suggest this causes a high false-positive discovery rate (>50%) in geographically structured populations. Selection differentials (¦s¦) are stronger in introduced than in native species, although selection gradients (¦β¦) are not, consistent with introduced species experiencing weaker genetic constraints. This could facilitate rapid adaptation, but evidence is limited. For example, rapid phenotypic evolution often manifests as geographical clines, but simulations demonstrate that nonadaptive trait clines can evolve frequently during colonization (~two-thirds of simulations). Additionally, QST-FST studies may often misrepresent the strength and form of natural selection acting during invasion. Instead, classic approaches in evolutionary ecology (e.g. selection analysis, reciprocal transplant, artificial selection) are necessary to determine the frequency of adaptive evolution during invasion and its influence on establishment, spread and impact of invasive species. These studies are rare but crucial for managing biological invasions in the context of global change.

  13. Wavelet multiresolution analyses adapted for the fast solution of boundary value ordinary differential equations

    NASA Technical Reports Server (NTRS)

    Jawerth, Bjoern; Sweldens, Wim

    1993-01-01

    We present ideas on how to use wavelets in the solution of boundary value ordinary differential equations. Rather than using classical wavelets, we adapt their construction so that they become (bi)orthogonal with respect to the inner product defined by the operator. The stiffness matrix in a Galerkin method then becomes diagonal and can thus be trivially inverted. We show how one can construct an O(N) algorithm for various constant and variable coefficient operators.

  14. Adaptive properties of differential learning rates for positive and negative outcomes.

    PubMed

    Cazé, Romain D; van der Meer, Matthijs A A

    2013-12-01

    The concept of the reward prediction error-the difference between reward obtained and reward predicted-continues to be a focal point for much theoretical and experimental work in psychology, cognitive science, and neuroscience. Models that rely on reward prediction errors typically assume a single learning rate for positive and negative prediction errors. However, behavioral data indicate that better-than-expected and worse-than-expected outcomes often do not have symmetric impacts on learning and decision-making. Furthermore, distinct circuits within cortico-striatal loops appear to support learning from positive and negative prediction errors, respectively. Such differential learning rates would be expected to lead to biased reward predictions and therefore suboptimal choice performance. Contrary to this intuition, we show that on static "bandit" choice tasks, differential learning rates can be adaptive. This occurs because asymmetric learning enables a better separation of learned reward probabilities. We show analytically how the optimal learning rate asymmetry depends on the reward distribution and implement a biologically plausible algorithm that adapts the balance of positive and negative learning rates from experience. These results suggest specific adaptive advantages for separate, differential learning rates in simple reinforcement learning settings and provide a novel, normative perspective on the interpretation of associated neural data.

  15. In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

    NASA Astrophysics Data System (ADS)

    Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji

    2007-05-01

    A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 µm spot diameter. It was revealed that a 45 µm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 µm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

  16. Genomic Analysis of Differentiation between Soil Types Reveals Candidate Genes for Local Adaptation in Arabidopsis lyrata

    PubMed Central

    Turner, Thomas L.; von Wettberg, Eric J.; Nuzhdin, Sergey V.

    2008-01-01

    Serpentine soil, which is naturally high in heavy metal content and has low calcium to magnesium ratios, comprises a difficult environment for most plants. An impressive number of species are endemic to serpentine, and a wide range of non-endemic plant taxa have been shown to be locally adapted to these soils. Locating genomic polymorphisms which are differentiated between serpentine and non-serpentine populations would provide candidate loci for serpentine adaptation. We have used the Arabidopsis thaliana tiling array, which has 2.85 million probes throughout the genome, to measure genetic differentiation between populations of Arabidopsis lyrata growing on granitic soils and those growing on serpentinic soils. The significant overrepresentation of genes involved in ion transport and other functions provides a starting point for investigating the molecular basis of adaptation to soil ion content, water retention, and other ecologically and economically important variables. One gene in particular, calcium-exchanger 7, appears to be an excellent candidate gene for adaptation to low Ca∶Mg ratio in A. lyrata. PMID:18784841

  17. Population genomic evidence for adaptive differentiation in the Baltic Sea herring.

    PubMed

    Guo, Baocheng; Li, Zitong; Merilä, Juha

    2016-06-01

    Detecting and estimating the degree of genetic differentiation among populations of highly mobile marine fish having pelagic larval stages is challenging because their effective population sizes can be large, and thus, little genetic drift and differentiation is expected in neutral genomic sites. However, genomic sites subject to directional selection stemming from variation in local environmental conditions can still show substantial genetic differentiation, yet these signatures can be hard to detect with low-throughput approaches. Using a pooled RAD-seq approach, we investigated genomewide patterns of genetic variability and differentiation within and among 20 populations of Atlantic herring in the Baltic Sea (and adjacent Atlantic sites), where previous low-throughput studies and/or studies based on few populations have found limited evidence for genetic differentiation. Stringent quality control was applied in the filtering of 1 791 254 SNPs, resulting in a final data set of 68 182 polymorphic loci. Clear differentiation was identified between Atlantic and Baltic populations in many genomic sites, while differentiation within the Baltic Sea area was weaker and geographically less structured. However, outlier analyses - whether including all populations or only those within the Baltic Sea - uncovered hundreds of directionally selected loci in which variability was associated with either salinity, temperature or both. Hence, our results support the view that although the degree of genetic differentiation among Baltic Sea herring populations is low, there are many genomic regions showing elevated divergence, apparently as a response to temperature- and salinity-related natural selection. As such, the results add to the increasing evidence of local adaptation in highly mobile marine organisms, and those in the young Baltic Sea in particular. PMID:27093194

  18. Population genomic evidence for adaptive differentiation in the Baltic Sea herring.

    PubMed

    Guo, Baocheng; Li, Zitong; Merilä, Juha

    2016-06-01

    Detecting and estimating the degree of genetic differentiation among populations of highly mobile marine fish having pelagic larval stages is challenging because their effective population sizes can be large, and thus, little genetic drift and differentiation is expected in neutral genomic sites. However, genomic sites subject to directional selection stemming from variation in local environmental conditions can still show substantial genetic differentiation, yet these signatures can be hard to detect with low-throughput approaches. Using a pooled RAD-seq approach, we investigated genomewide patterns of genetic variability and differentiation within and among 20 populations of Atlantic herring in the Baltic Sea (and adjacent Atlantic sites), where previous low-throughput studies and/or studies based on few populations have found limited evidence for genetic differentiation. Stringent quality control was applied in the filtering of 1 791 254 SNPs, resulting in a final data set of 68 182 polymorphic loci. Clear differentiation was identified between Atlantic and Baltic populations in many genomic sites, while differentiation within the Baltic Sea area was weaker and geographically less structured. However, outlier analyses - whether including all populations or only those within the Baltic Sea - uncovered hundreds of directionally selected loci in which variability was associated with either salinity, temperature or both. Hence, our results support the view that although the degree of genetic differentiation among Baltic Sea herring populations is low, there are many genomic regions showing elevated divergence, apparently as a response to temperature- and salinity-related natural selection. As such, the results add to the increasing evidence of local adaptation in highly mobile marine organisms, and those in the young Baltic Sea in particular.

  19. Electrochemical Analysis of Antichemotherapeutic Drug Zanosar in Pharmaceutical and Biological Samples by Differential Pulse Polarography

    PubMed Central

    Reddy, Chennupalle Nageswara; ReddyPrasad, Puthalapattu; Sreedhar, NeelamYughandhar

    2013-01-01

    The electrochemical reduction of zanosar was investigated systematically by direct current polarography, cyclic voltammetry, and differential pulse polarography (DPP). A simple DPP technique was proposed for the direct quantitative determination of anticancer drug zanosar in pharmaceutical formulation and spiked human urine samples for the first time. The reduction potential was −0.28 V versus Ag/AgCl with a hanging mercury drop electrode in Britton-Robinson buffer as supporting electrolyte. The dependence of the intensities of currents and potentials on pH, concentration, scan rate, deposition time, and nature of the supporting electrolyte was investigated. The calibration curve was found to be linear with the following equation: y = 0.4041x + 0.012, with a correlation coefficient of 0.992 (R2) over a concentration range from 1.0 × 10−7 M to 1.0 × 10−3 M. In the present investigation, the achieved limit of detection (LOD) and limit of quantization (LQD) were 7.42 × 10−8 M and 2.47 × 10−8 M; respectively. Excipients did not interfere with the determination of zanosar in pharmaceutical formulation and spiked urine samples. Precision and accuracy of the developed method were checked by recovery studies in pharmaceutical formulation and spiked human urine samples. PMID:24455423

  20. A Dual Mode Pulsed Electro-Magnetic Cell Stimulator Produces Acceleration of Myogenic Differentiation

    PubMed Central

    Leon-Salas, Walter D.; Rizk, Hatem; Mo, Chenglin; Weisleder, Noah; Brotto, Leticia; Abreu, Eduardo; Brotto, Marco

    2013-01-01

    This paper presents the design and test of a dual-mode electric and magnetic biological stimulator (EM-Stim). The stimulator generates pulsing electric and magnetic fields at programmable rates and intensities. While electric and magnetic stimulators have been reported before, this is the first device that combines both modalities. The ability of the dual stimulation to target bone and muscle tissue simultaneously has the potential to improve the therapeutic treatment of osteoporosis and sarcopenia. The device is fully programmable, portable and easy to use, and can run from a battery or a power supply. The device can generate magnetic fields of up to 1.6 mT and output voltages of +/−40 V. The EM-Stim accelerated myogenic differentiation of myoblasts into myotubes as evidenced by morphometric, gene expression, and protein content analyses. Currently, there are many patents concerned with the application of single electrical or magnetic stimulation, but none that combine both simultaneously. However, we applied for and obtained a provisional patent for new device to fully explore its therapeutic potential in pre-clinical models. PMID:23445453

  1. Differential pulse voltammetric determination of eugenol at a pencil graphite electrode.

    PubMed

    Sağlam, Özlem; Dilgin, Didem Giray; Ertek, Bensu; Dilgin, Yusuf

    2016-03-01

    In this study, the electrochemical behavior of eugenol, a widely used herbal drug, was investigated at a pencil graphite electrode (PGE). A low-cost, disposable, sensitive and selective electrochemical sensor is proposed for the determination of eugenol by recording its differential pulse voltammograms in Britton-Robinson buffer solution containing 0.1 M KCl with pH of 2.0 at the PGE. The PGE displayed a very good electrochemical behavior with significant enhancement of the peak current compared to a glassy carbon electrode. Under experimental conditions, the PGE had a linear response range from 0.3 μM to 50.0 μM eugenol with a detection limit of 0.085 μM (based on 3S(b)). Relative standard deviations of 2.4 and 4.8% were obtained for five successive determinations of 30.0 and 5.0 μM eugenol, respectively, which indicate acceptable repeatability. This voltammetric method was successfully applied for the direct determination of eugenol in real samples. The effect of various interfering compounds on the eugenol peak current was also studied.

  2. Gold nanoparticles modified carbon paste electrode for differential pulse voltammetric determination of eugenol.

    PubMed

    Afzali, Daryoush; Zarei, Somaye; Fathirad, Fariba; Mostafavi, Ali

    2014-10-01

    In the present study, a carbon paste electrode chemically modified with gold nanoparticles was used as a sensitive electrochemical sensor for determination of eugenol. The differential pulse voltammetric method was employed to study the behavior of eugenol on this modified electrode. The effect of variables such as percent of gold nanoparticles, pH of solution, accumulation potential and time on voltammogram peak current were optimized. The proposed electrode showed good oxidation response for eugenol in 0.1 mol L(-1) phosphate buffer solution (pH8) and the peak potential was about +285 mV (vs. Ag/AgCl). The peak current increased linearly with the eugenol concentration in the range of 5-250 μmol L(-1). The detection limit was found to be 2.0 μmol L(-1) and the relative standard deviation was 1.2% (n=7). The effect of interferences on the eugenol peak current was studied. The method has been applied to the determination of eugenol in different real samples, spiked recoveries were in the range of 96%-99%.

  3. Determination of Bosentan in Pharmaceutical Preparations by Linear Sweep, Square Wave and Differential Pulse Voltammetry Methods

    PubMed Central

    Atila, Alptug; Yilmaz, Bilal

    2015-01-01

    In this study, simple, fast and reliable cyclic voltammetry (CV), linear sweep voltammetry (LSV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV) methods were developed and validated for determination of bosentan in pharmaceutical preparations. The proposed methods were based on electrochemical oxidation of bosentan at platinum electrode in acetonitrile solution containing 0.1 M TBACIO4. The well-defined oxidation peak was observed at 1.21 V. The calibration curves were linear for bosentan at the concentration range of 5-40 µg/mL for LSV and 5-35 µg/mL for SWV and DPV methods, respectively. Intra- and inter-day precision values for bosentan were less than 4.92, and accuracy (relative error) was better than 6.29%. The mean recovery of bosentan was 100.7% for pharmaceutical preparations. No interference was found from two tablet excipients at the selected assay conditions. Developed methods in this study are accurate, precise and can be easily applied to Tracleer and Diamond tablets as pharmaceutical preparation. PMID:25901151

  4. Double preconcentration of trace amounts of cadmium in nail samples and measurement by differential pulse voltammetry.

    PubMed

    Shahi, Somayeh; Nateghi, Mohammad Reza

    2015-04-01

    Cadion was coated on carbon powder and used as a solid phase for selective extraction and preconcentration of cadmium ions. Complexed cadmium ions were eluted from solid phase by 5 mL, nitric acid (2.0 M) with the flow rate of 2 mL min(-1).The resulted solution was used for accumulation of the cadmium metal at the surface of the carbon paste electrode at -1.3 V reduction potential. Finally, cadmium was reoxidized and the differential pulse voltammogram recorded at the potential range of -0.55 to -0.2 V. Calibration graph was plotted in the concentration range of 0.5-50 μg L(-1) of cadmium. Detection limit 0.06 μg L(-1) was calculated based on the 3 Sb/m. The RSD was 9.13 % (n = 4) for cadmium concentration of 10 μg L(-1) with preconcentration factor of 100. Method was successfully used for the determination of cadmium in finger nail samples and after spiking the samples, the recoveries were evaluated >96 %.

  5. Sensitive quantitation of Ochratoxin A in cocoa beans using differential pulse voltammetry based aptasensor.

    PubMed

    Mishra, Rupesh K; Hayat, Akhtar; Catanante, Gaëlle; Istamboulie, Georges; Marty, Jean-Louis

    2016-02-01

    In this work, we propose for the first time a sensitive Ochratoxin A (OTA) detection in cocoa beans using competitive aptasensor by differential pulse voltammetry (DPV). In the proposed method, biotin labeled and free OTA competed to bind with immobilized aptamer onto the surface of a screen printed carbon electrode (SPCE), and percentage binding was calculated. The detection was performed after adding avidin-ALP to perform avidin-biotin reaction; the signal was generated through a suitable substrate 1-naphthyl phosphate (1-NP), for alkaline phosphatase (ALP). The cocoa samples were extracted and purified using molecular imprinted polymer (MIP) columns specifically designed for OTA. The developed aptasensor showed a good linearity in the range 0.15-5 ng/mL with the limit of detection (LOD) 0.07 ng/mL and 3.7% relative standard deviation (RSD). The aptasensor displayed good recovery values in the range 82.1-85% with 3.87% RSD, thus, demonstrated the efficiency of proposed aptasensor for such matrices.

  6. Determination of bosentan in pharmaceutical preparations by linear sweep, square wave and differential pulse voltammetry methods.

    PubMed

    Atila, Alptug; Yilmaz, Bilal

    2015-01-01

    In this study, simple, fast and reliable cyclic voltammetry (CV), linear sweep voltammetry (LSV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV) methods were developed and validated for determination of bosentan in pharmaceutical preparations. The proposed methods were based on electrochemical oxidation of bosentan at platinum electrode in acetonitrile solution containing 0.1 M TBACIO4. The well-defined oxidation peak was observed at 1.21 V. The calibration curves were linear for bosentan at the concentration range of 5-40 µg/mL for LSV and 5-35 µg/mL for SWV and DPV methods, respectively. Intra- and inter-day precision values for bosentan were less than 4.92, and accuracy (relative error) was better than 6.29%. The mean recovery of bosentan was 100.7% for pharmaceutical preparations. No interference was found from two tablet excipients at the selected assay conditions. Developed methods in this study are accurate, precise and can be easily applied to Tracleer and Diamond tablets as pharmaceutical preparation.

  7. Nanosecond pulsed electric fields have differential effects on cells in the S-phase.

    PubMed

    Hall, Emily H; Schoenbach, Karl H; Beebe, Stephen J

    2007-03-01

    Nanosecond pulsed electric fields (nsPEFs) are a type of nonthermal, nonionizing radiation that exhibit intense electric fields with high power, but low energy. NsPEFs extend conventional electroporation (EP) to affect intracellular structures and functions and depending on the intensity, can induce lethal and nonlethal cell signaling. In this study, HCT116 human colon carcinoma cells were synchronized to the S-phase or remained unsynchronized, exposed to electric fields of 60 kV/cm with either 60-ns or 300-ns durations, and analyzed for apoptosis and proliferative markers. Several nsPEF structural and functional targets were identified. Unlike unsynchronized cells, S-phase cells under limiting conditions exhibited greater membrane integrity and caspase activation and maintained cytoskeletal structure. Regardless of synchronization, cells exposed to nsPEFs under these conditions primarily survived, but exhibited some turnover and delayed proliferation in cell populations, as well as reversible increases in phosphatidylserine externalization, membrane integrity, and nuclei size. These results show that nsPEFs can act as a nonligand agonist to modulate plasma membrane (PM) and intracellular structures and functions, as well as differentially affect cells in the S-phase, but without effect on cell survival. Furthermore, nsPEF effects on the nucleus and cytoskeleton may provide synergistic therapeutic actions with other agents, such as ionizing radiation or chemotherapeutics that affect these same structures.

  8. Differential pulse voltammetric determination of acyclovir in pharmaceutical preparations using a pencil graphite electrode.

    PubMed

    Dilgin, Didem Giray; Karakaya, Serkan

    2016-06-01

    In this study, a new selective and sensitive voltammetric procedure for determination of acyclovir (ACV) was proposed using a disposable electrode, pencil graphite electrode (PGE). Cyclic and differential pulse voltammograms of ACV were recorded in Britton-Robinson buffer solution containing 0.10 M KCl with pH of 4.0 at PGE. The PGE displayed a very good electrochemical behavior with significant enhancement of the peak current compared to a glassy carbon electrode (GCE). Under experimental conditions, the PGE had a linear response range from 1.0 μM to 100.0 μM ACV with a detection limit of 0.3 μM (based on 3 Sb). Relative standard deviations of 4.8 and 3.6% were obtained for five successive determinations of 10.0 and 50.0 μM ACV, respectively, which indicate acceptable repeatability. This voltammetric method was successfully applied to the direct determination of ACV in real pharmaceutical samples. The effect of various interfering compounds on the ACV peak current was studied. PMID:27040252

  9. Sensitive quantitation of Ochratoxin A in cocoa beans using differential pulse voltammetry based aptasensor.

    PubMed

    Mishra, Rupesh K; Hayat, Akhtar; Catanante, Gaëlle; Istamboulie, Georges; Marty, Jean-Louis

    2016-02-01

    In this work, we propose for the first time a sensitive Ochratoxin A (OTA) detection in cocoa beans using competitive aptasensor by differential pulse voltammetry (DPV). In the proposed method, biotin labeled and free OTA competed to bind with immobilized aptamer onto the surface of a screen printed carbon electrode (SPCE), and percentage binding was calculated. The detection was performed after adding avidin-ALP to perform avidin-biotin reaction; the signal was generated through a suitable substrate 1-naphthyl phosphate (1-NP), for alkaline phosphatase (ALP). The cocoa samples were extracted and purified using molecular imprinted polymer (MIP) columns specifically designed for OTA. The developed aptasensor showed a good linearity in the range 0.15-5 ng/mL with the limit of detection (LOD) 0.07 ng/mL and 3.7% relative standard deviation (RSD). The aptasensor displayed good recovery values in the range 82.1-85% with 3.87% RSD, thus, demonstrated the efficiency of proposed aptasensor for such matrices. PMID:26304413

  10. Performance of differential amplitude pulse-position modulation with RZ coding for indoor optical wireless links

    NASA Astrophysics Data System (ADS)

    Sethakaset, Ubolthip; Gulliver, T. Aaron

    2005-02-01

    We investigate the performance of a differential amplitude pulse-position modulation with return-to-zero coding (DAPPM-RZ) over an indoor optical wireless channel. We compare the performance of DAPPM-RZ(A=2) with DAPPM(A=2), DPPM and DH-PIM. The result shows that, over a non-dispersive channel, DAPPM-RZ yields better power efficiency than DAPPM. It requires about 1.5 dB less transmit power. However, the bandwidth of DAPPM-RZ is double that of DAPPM. Compared to DPPM, the bandwidth of DAPPM-RZ is about the same as that of DPPM but DAPPM-RZ yields less power efficiency. When the number of bits/symbol(M) is above 3, the DAPPM-RZ is superior to DH-PIM_2 in terms of power efficiency but has less bandwidth efficiency. Over a dispersive channel, given the same value of M, DAPPM-RZ outperforms DPPM, DAPPM (without RZ) and DH-PIM2 when the normalized rms delay spread is high.

  11. Differential pulse voltammetric determination of acyclovir in pharmaceutical preparations using a pencil graphite electrode.

    PubMed

    Dilgin, Didem Giray; Karakaya, Serkan

    2016-06-01

    In this study, a new selective and sensitive voltammetric procedure for determination of acyclovir (ACV) was proposed using a disposable electrode, pencil graphite electrode (PGE). Cyclic and differential pulse voltammograms of ACV were recorded in Britton-Robinson buffer solution containing 0.10 M KCl with pH of 4.0 at PGE. The PGE displayed a very good electrochemical behavior with significant enhancement of the peak current compared to a glassy carbon electrode (GCE). Under experimental conditions, the PGE had a linear response range from 1.0 μM to 100.0 μM ACV with a detection limit of 0.3 μM (based on 3 Sb). Relative standard deviations of 4.8 and 3.6% were obtained for five successive determinations of 10.0 and 50.0 μM ACV, respectively, which indicate acceptable repeatability. This voltammetric method was successfully applied to the direct determination of ACV in real pharmaceutical samples. The effect of various interfering compounds on the ACV peak current was studied.

  12. Differentially expressed genes associated with adaptation to different thermal environments in three sympatric Cuban Anolis lizards.

    PubMed

    Akashi, Hiroshi D; Cádiz Díaz, Antonio; Shigenobu, Shuji; Makino, Takashi; Kawata, Masakado

    2016-05-01

    How animals achieve evolutionary adaptation to different thermal environments is an important issue for evolutionary biology as well as for biodiversity conservation in the context of recent global warming. In Cuba, three sympatric species of Anolis lizards (Anolis allogus, A. homolechis and A. sagrei) inhabit different thermal microhabitats, thereby providing an excellent opportunity to examine how they have adapted to different environmental temperatures. Here, we performed RNA-seq on the brain, liver and skin tissues from these three species to analyse their transcriptional responses at two different temperatures. In total, we identified 400, 816 and 781 differentially expressed genes (DEGs) between the two temperatures in A. allogus, A. homolechis and A. sagrei, respectively. Only 62 of these DEGs were shared across the three species, indicating that global transcriptional responses have diverged among these species. Gene ontology (GO) analysis showed that large numbers of ribosomal protein genes were DEGs in the warm-adapted A. homolechis, suggesting that the upregulation of protein synthesis is an important physiological mechanism in the adaptation of this species to hotter environments. GO analysis also showed that GO terms associated with circadian regulation were enriched in all three species. A gene associated with circadian regulation, Nr1d1, was detected as a DEG with opposite expression patterns between the cool-adapted A. allogus and the hot-adapted A. sagrei. Because the environmental temperature fluctuates more widely in open habitats than in forests throughout the day, the circadian thermoregulation could also be important for adaptation to distinct thermal habitats.

  13. Size differentiation in Finnish house sparrows follows Bergmann's rule with evidence of local adaptation.

    PubMed

    Brommer, J E; Hanski, I K; Kekkonen, J; Väisänen, R A

    2014-04-01

    Bergmann's rule predicts that individuals are larger in more poleward populations and that this size gradient has an adaptive basis. Hence, phenotypic divergence in size traits between populations (PST ) is expected to exceed the level of divergence by drift alone (FST ). We measured 16 skeletal traits, body mass and wing length in 409 male and 296 female house sparrows Passer domesticus sampled in 12 populations throughout Finland, where the species has its northernmost European distributional margin. Morphometric differentiation across populations (PST ) was compared with differentiation in 13 microsatellites (FST ). We find that twelve traits phenotypically diverged more than FST in both sexes, and an additional two traits diverged in males. The phenotypic divergence exceeded FST in several traits to such a degree that findings were robust also to strong between-population environmental effects. Divergence was particularly strong in dimensions of the bill, making it a strong candidate for the study of adaptive molecular genetic divergence. Divergent traits increased in size in more northern populations. We conclude that house sparrows show evidence of an adaptive latitudinal size gradient consistent with Bergmann's rule on the modest spatial scale of ca. 600 km.

  14. Accelerating Markov chain Monte Carlo simulation by differential evolution with self-adaptive randomized subspace sampling

    SciTech Connect

    Vrugt, Jasper A; Hyman, James M; Robinson, Bruce A; Higdon, Dave; Ter Braak, Cajo J F; Diks, Cees G H

    2008-01-01

    Markov chain Monte Carlo (MCMC) methods have found widespread use in many fields of study to estimate the average properties of complex systems, and for posterior inference in a Bayesian framework. Existing theory and experiments prove convergence of well constructed MCMC schemes to the appropriate limiting distribution under a variety of different conditions. In practice, however this convergence is often observed to be disturbingly slow. This is frequently caused by an inappropriate selection of the proposal distribution used to generate trial moves in the Markov Chain. Here we show that significant improvements to the efficiency of MCMC simulation can be made by using a self-adaptive Differential Evolution learning strategy within a population-based evolutionary framework. This scheme, entitled DiffeRential Evolution Adaptive Metropolis or DREAM, runs multiple different chains simultaneously for global exploration, and automatically tunes the scale and orientation of the proposal distribution in randomized subspaces during the search. Ergodicity of the algorithm is proved, and various examples involving nonlinearity, high-dimensionality, and multimodality show that DREAM is generally superior to other adaptive MCMC sampling approaches. The DREAM scheme significantly enhances the applicability of MCMC simulation to complex, multi-modal search problems.

  15. Complementary effect of natural and sexual selection against immigrants maintains differentiation between locally adapted fish

    NASA Astrophysics Data System (ADS)

    Plath, Martin; Riesch, Rüdiger; Oranth, Alexandra; Dzienko, Justina; Karau, Nora; Schießl, Angela; Stadler, Stefan; Wigh, Adriana; Zimmer, Claudia; Arias-Rodriguez, Lenin; Schlupp, Ingo; Tobler, Michael

    2010-08-01

    Adaptation to ecologically heterogeneous environments can drive speciation. But what mechanisms maintain reproductive isolation among locally adapted populations? Using poeciliid fishes in a system with naturally occurring toxic hydrogen sulfide, we show that (a) fish from non-sulfidic sites ( Poecilia mexicana) show high mortality (95 %) after 24 h when exposed to the toxicant, while locally adapted fish from sulfidic sites ( Poecilia sulphuraria) experience low mortality (13 %) when transferred to non-sulfidic water. (b) Mate choice tests revealed that P. mexicana females exhibit a preference for conspecific males in non-sulfidic water, but not in sulfidic water, whereas P. sulphuraria females never showed a preference. Increased costs of mate choice in sulfidic, hypoxic water, and the lack of selection for reinforcement due to the low survival of P. mexicana may explain the absence of a preference in P. sulphuraria females. Taken together, our study may be the first to demonstrate independent—but complementary—effects of natural and sexual selection against immigrants maintaining differentiation between locally adapted fish populations.

  16. Multiple wall-reflection effect in adaptive-array differential-phase reflectometry on QUEST

    NASA Astrophysics Data System (ADS)

    Idei, H.; Mishra, K.; Yamamoto, M. K.; Fujisawa, A.; Nagashima, Y.; Hamasaki, M.; Hayashi, Y.; Onchi, T.; Hanada, K.; Zushi, H.; QUEST Team

    2016-01-01

    A phased array antenna and Software-Defined Radio (SDR) heterodyne-detection systems have been developed for adaptive array approaches in reflectometry on the QUEST. In the QUEST device considered as a large oversized cavity, standing wave (multiple wall-reflection) effect was significantly observed with distorted amplitude and phase evolution even if the adaptive array analyses were applied. The distorted fields were analyzed by Fast Fourier Transform (FFT) in wavenumber domain to treat separately the components with and without wall reflections. The differential phase evolution was properly obtained from the distorted field evolution by the FFT procedures. A frequency derivative method has been proposed to overcome the multiple-wall reflection effect, and SDR super-heterodyned components with small frequency difference for the derivative method were correctly obtained using the FFT analysis.

  17. Burkholderia cenocepacia Differential Gene Expression during Host–Pathogen Interactions and Adaptation to the Host Environment

    PubMed Central

    O’Grady, Eoin P.; Sokol, Pamela A.

    2011-01-01

    Members of the Burkholderia cepacia complex (Bcc) are important in medical, biotechnological, and agricultural disciplines. These bacteria naturally occur in soil and water environments and have adapted to survive in association with plants and animals including humans. All Bcc species are opportunistic pathogens including Burkholderia cenocepacia that causes infections in cystic fibrosis and chronic granulomatous disease patients. The adaptation of B. cenocepacia to the host environment was assessed in a rat chronic respiratory infection model and compared to that of high cell-density in vitro grown cultures using transcriptomics. The distribution of genes differentially expressed on chromosomes 1, 2, and 3 was relatively proportional to the size of each genomic element, whereas the proportion of plasmid-encoded genes differentially expressed was much higher relative to its size and most genes were induced in vivo. The majority of genes encoding known virulence factors, components of types II and III secretion systems and chromosome 2-encoded type IV secretion system were similarly expressed between in vitro and in vivo environments. Lower expression in vivo was detected for genes encoding N-acyl-homoserine lactone synthase CepI, orphan LuxR homolog CepR2, zinc metalloproteases ZmpA and ZmpB, LysR-type transcriptional regulator ShvR, nematocidal protein AidA, and genes associated with flagellar motility, Flp type pilus formation, and type VI secretion. Plasmid-encoded type IV secretion genes were markedly induced in vivo. Additional genes induced in vivo included genes predicted to be involved in osmotic stress adaptation or intracellular survival, metal ion, and nutrient transport, as well as those encoding outer membrane proteins. Genes identified in this study are potentially important for virulence during host–pathogen interactions and may be associated with survival and adaptation to the host environment during chronic lung infections. PMID:22919581

  18. The consequences of dominance and gene flow for local adaptation and differentiation at two linked loci

    PubMed Central

    Akerman, Ada; Bürger, Reinhard

    2014-01-01

    For a subdivided population the consequences of dominance and gene flow for the maintenance of multilocus polymorphism, local adaptation, and differentiation are investigated. The dispersing population inhabits two demes in which selection acts in opposite direction. Fitness is determined additively by two linked diallelic loci with arbitrary intermediate dominance (no over- or underdominance). For weak as well as strong migration, the equilibrium structure is derived. As a special case, a continuous-time continent–island model (CI model) is analyzed, with one-way migration from the continent to the island. For this CI model, the equilibrium and stability configuration is obtained explicitly for weak migration, for strong migration, for independent loci, and for complete linkage. For independent loci, the possible bifurcation patterns are derived as functions of the migration rate. These patterns depend strongly on the degree of dominance. The effects of dominance, linkage, and migration on the amount of linkage disequilibrium (LD) and the degree of local adaptation are explored. Explicit formulas are obtained for D   (=x1x4−x2x3) and r2 (the squared correlation in allelic state). They demonstrate that dominant island alleles increase D and decrease r2. Local adaptation is elevated by dominance of the locally adaptive alleles. The effective migration rate at a linked neutral locus is calculated. If advantageous alleles are dominant, it is decreased only slightly below the actual migration rate. For a quantitative trait that is determined by two additive loci, the influence of dominance on measures of differentiation is studied. Explicit expressions for QST and two types of FST at equilibrium are deduced and their relation is discussed. PMID:24793653

  19. Genetic and morphological differentiation in Populus nigra L.: isolation by colonization or isolation by adaptation?

    PubMed Central

    DeWoody, Jennifer; Trewin, Harriet; Taylor, Gail

    2015-01-01

    Identifying processes underlying the genetic and morphological differences among populations is a central question of evolutionary biology. Forest trees typically contain high levels of neutral genetic variation, and genetic differences are often correlated with geographic distance between populations [isolation by distance (IBD)] or are due to historic vicariance events [isolation by colonization (IBC)]. In contrast, morphological differences are largely due to local adaptation. Here, we examined genetic (microsatellite) and morphological (from a common garden experiment) variation in Populus nigra L., European black poplar, collected from 13 sites across western Europe and grown in a common garden in Belgium. Significant genetic differentiation was observed, with populations from France displaying greater admixture than the distinct Spanish and central European gene pools, consistent with previously described glacial refugia (IBC). Many quantitative traits displayed a bimodal distribution, approximately corresponding to small-leaf and large-leaf ecotypes. Examination of nine climatic variables revealed the sampling locations to have diverse climates, and although the correlation between morphological and climatic differences was significant, the pattern was not consistent with strict local adaptation. Partial Mantel tests based on multivariate summary statistics identified significant residual correlation in comparisons of small-leaf to large-leaf ecotypes, and within the small-leaf samples, but not within large-leaf ecotypes, indicating that variation within the small-leaf morphotype in particular may be adaptive. Some small-leaf populations experience climates very similar to those in large-leaf sites. We conclude that adaptive differentiation and persistent IBC acted in combination to produce the genetic and morphological patterns observed in P. nigra. PMID:25857321

  20. Multiobjective Image Color Quantization Algorithm Based on Self-Adaptive Hybrid Differential Evolution

    PubMed Central

    Xia, Xuewen

    2016-01-01

    In recent years, some researchers considered image color quantization as a single-objective problem and applied heuristic algorithms to solve it. This paper establishes a multiobjective image color quantization model with intracluster distance and intercluster separation as its objectives. Inspired by a multipopulation idea, a multiobjective image color quantization algorithm based on self-adaptive hybrid differential evolution (MoDE-CIQ) is then proposed to solve this model. Two numerical experiments on four common test images are conducted to analyze the effectiveness and competitiveness of the multiobjective model and the proposed algorithm. PMID:27738423

  1. Adaptive neural network nonlinear control for BTT missile based on the differential geometry method

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Wang, Yongji; Xu, Jiangsheng

    2007-11-01

    A new nonlinear control strategy incorporated the differential geometry method with adaptive neural networks is presented for the nonlinear coupling system of Bank-to-Turn missile in reentry phase. The basic control law is designed using the differential geometry feedback linearization method, and the online learning neural networks are used to compensate the system errors due to aerodynamic parameter errors and external disturbance in view of the arbitrary nonlinear mapping and rapid online learning ability for multi-layer neural networks. The online weights and thresholds tuning rules are deduced according to the tracking error performance functions by Levenberg-Marquardt algorithm, which will make the learning process faster and more stable. The six degree of freedom simulation results show that the attitude angles can track the desired trajectory precisely. It means that the proposed strategy effectively enhance the stability, the tracking performance and the robustness of the control system.

  2. Adaptive Epigenetic Differentiation between Upland and Lowland Rice Ecotypes Revealed by Methylation-Sensitive Amplified Polymorphism

    PubMed Central

    Xiong, Jie; Tao, Tao; Zheng, Xiaoguo; Wei, Haibin; Yue, Yunxia; Chen, Liang; Luo, Lijun

    2016-01-01

    The stress-induced epimutations could be inherited over generations and play important roles in plant adaption to stressful environments. Upland rice has been domesticated in water-limited environments for thousands of years and accumulated drought-induced epimutations of DNA methylation, making it epigenetically differentiated from lowland rice. To study the epigenetic differentiation between upland and lowland rice ecotypes on their drought-resistances, the epigenetic variation was investigated in 180 rice landraces under both normal and osmotic conditions via methylation-sensitive amplified polymorphism (MSAP) technique. Great alterations (52.9~54.3% of total individual-locus combinations) of DNA methylation are recorded when rice encountering the osmotic stress. Although the general level of epigenetic differentiation was very low, considerable level of ΦST (0.134~0.187) was detected on the highly divergent epiloci (HDE). The HDE detected in normal condition tended to stay at low levels in upland rice, particularly the ones de-methylated in responses to osmotic stress. Three out of four selected HDE genes differentially expressed between upland and lowland rice under normal or stressed conditions. Moreover, once a gene at HDE was up-/down-regulated in responses to the osmotic stress, its expression under the normal condition was higher/lower in upland rice. This result suggested expressions of genes at the HDE in upland rice might be more adaptive to the osmotic stress. The epigenetic divergence and its influence on the gene expression should contribute to the higher drought-resistance in upland rice as it is domesticated in the water-limited environment. PMID:27380174

  3. Differential effects of magnetic pulses on the orientation of naturally migrating birds.

    PubMed

    Holland, Richard A

    2010-11-01

    In migratory passerine birds, strong magnetic pulses are thought to be diagnostic of the remagnetization of iron minerals in a putative sensory system contained in the beak. Previous evidence suggests that while such a magnetic pulse affects the orientation of migratory birds in orientation cages, no effect was present when pulse-treated birds were tested in natural migration. Here we show that two migrating passerine birds treated with a strong magnetic pulse, designed to alter the magnetic sense, migrated in a direction that differed significantly from that of controls when tested in natural conditions. The orientation of treated birds was different depending on the alignment of the pulse with respect to the magnetic field. These results can aid in advancing understanding of how the putative iron-mineral-based receptors found in birds' beaks may be used to detect and signal the intensity and/or direction of the Earth's magnetic field.

  4. Differential effects of magnetic pulses on the orientation of naturally migrating birds

    PubMed Central

    Holland, Richard A.

    2010-01-01

    In migratory passerine birds, strong magnetic pulses are thought to be diagnostic of the remagnetization of iron minerals in a putative sensory system contained in the beak. Previous evidence suggests that while such a magnetic pulse affects the orientation of migratory birds in orientation cages, no effect was present when pulse-treated birds were tested in natural migration. Here we show that two migrating passerine birds treated with a strong magnetic pulse, designed to alter the magnetic sense, migrated in a direction that differed significantly from that of controls when tested in natural conditions. The orientation of treated birds was different depending on the alignment of the pulse with respect to the magnetic field. These results can aid in advancing understanding of how the putative iron-mineral-based receptors found in birds' beaks may be used to detect and signal the intensity and/or direction of the Earth's magnetic field. PMID:20453067

  5. Identification of genes involved in the drought adaptation and recovery in Portulaca oleracea by differential display.

    PubMed

    D'Andrea, Rodrigo Matías; Triassi, Agustina; Casas, María Isabel; Andreo, Carlos Santiago; Lara, María Valeria

    2015-05-01

    Portulaca oleracea is one of the richest plant sources of ω-3 and ω-6 fatty acids and other compounds potentially valuable for nutrition. It is broadly established in arid, semiarid and well-watered fields, thus making it a promising candidate for research on abiotic stress resistance mechanisms. It is capable of withstanding severe drought and then of recovering upon rehydration. Here, the adaptation to drought and the posterior recovery was evaluated at transcriptomic level by differential display validated by qRT-PCR. Of the 2279 transcript-derived fragments amplified, 202 presented differential expression. Ninety of them were successfully isolated and sequenced. Selected genes were tested against different abiotic stresses in P. oleracea and the behavior of their orthologous genes in Arabidopsis thaliana was also explored to seek for conserved response mechanisms. In drought adapted and in recovered plants changes in expression of many protein metabolism-, lipid metabolism- and stress-related genes were observed. Many genes with unknown function were detected, which also respond to other abiotic stresses. Some of them are also involved in the seed desiccation/imbibition process and thus would be of great interest for further research. The potential use of candidate genes to engineer drought tolerance improvement and recovery is discussed.

  6. Designing STUD Pulses to control laser-plasma instabilities and adapt to changing plasma conditions

    NASA Astrophysics Data System (ADS)

    Afeyan, Bedros; Hüller, Stefan

    2011-10-01

    Designing spike trains of uneven duration and delay, or STUD pulses, for ICF targets in direct and indirect drive and for shock ignition will be explored. Taming stimulated Raman and Brillouin scattering (SRS and SBS) as well as two plasmon decay, and harnessing their hot electron generation properties for fast heating purposes at higher intensities will be explored. Theoretical statistical models capturing the essential physics of STUD pulse propagation, hot spot scrambling and SRS and SBS interaction will be presented. How to control LPI in crossing pairs of beams by staggering or interleaving their STUD pulse profiles when no interaction is desired and overlapping them when energy transfer is desirable, will be demonstrated. Technological advances required to bring about the STUD pulse program including time lenses for psec time scale modulated pulses and psec time scale resolved SRS and SBS detection lasting for nsecs and laser hot spot scrambling plasma cells will be discussed. Work supported by a grant from DOE NNSA SSAA Program and a Phase I SBIR from OFES.

  7. Adaptive Light Modulation for Improved Resolution and Efficiency in All-Optical Pulse-Echo Ultrasound.

    PubMed

    Alles, Erwin J; Colchester, Richard J; Desjardins, Adrien E

    2016-01-01

    In biomedical all-optical pulse-echo ultrasound systems, ultrasound is generated with the photoacoustic effect by illuminating an optically absorbing structure with a temporally modulated light source. Nanosecond range laser pulses are typically used, which can yield bandwidths exceeding 100 MHz. However, acoustical attenuation within tissue or nonuniformities in the detector or source power spectra result in energy loss at the affected frequencies and in a reduced overall system efficiency. In this work, a laser diode is used to generate linear and nonlinear chirp optical modulations that are extended to microsecond time scales, with bandwidths constrained to the system sensitivity. Compared to those obtained using a 2-ns pulsed laser, pulse-echo images of a phantom obtained using linear chirp excitation exhibit similar axial resolution (99 versus 92 μm, respectively) and signal-to-noise ratios (SNRs) (10.3 versus 9.6 dB). In addition, the axial point spread function (PSF) exhibits lower sidelobe levels in the case of chirp modulation. Using nonlinear (time-stretched) chirp excitations, where the nonlinearity is computed from measurements of the spectral sensitivity of the system, the power spectrum of the imaging system was flattened and its bandwidth broadened. Consequently, the PSF has a narrower axial extent and still lower sidelobe levels. Pulse-echo images acquired with time-stretched chirps as optical modulation have higher axial resolution (64 μm) than those obtained with linear chirps, at the expense of a lower SNR (6.8 dB). Using a linear or time-stretched chirp, the conversion efficiency from optical power to acoustical pressure improved by a factor of 70 or 61, respectively, compared to that obtained with pulsed excitation. PMID:26552084

  8. Adaptive Light Modulation for Improved Resolution and Efficiency in All-Optical Pulse-Echo Ultrasound.

    PubMed

    Alles, Erwin J; Colchester, Richard J; Desjardins, Adrien E

    2016-01-01

    In biomedical all-optical pulse-echo ultrasound systems, ultrasound is generated with the photoacoustic effect by illuminating an optically absorbing structure with a temporally modulated light source. Nanosecond range laser pulses are typically used, which can yield bandwidths exceeding 100 MHz. However, acoustical attenuation within tissue or nonuniformities in the detector or source power spectra result in energy loss at the affected frequencies and in a reduced overall system efficiency. In this work, a laser diode is used to generate linear and nonlinear chirp optical modulations that are extended to microsecond time scales, with bandwidths constrained to the system sensitivity. Compared to those obtained using a 2-ns pulsed laser, pulse-echo images of a phantom obtained using linear chirp excitation exhibit similar axial resolution (99 versus 92 μm, respectively) and signal-to-noise ratios (SNRs) (10.3 versus 9.6 dB). In addition, the axial point spread function (PSF) exhibits lower sidelobe levels in the case of chirp modulation. Using nonlinear (time-stretched) chirp excitations, where the nonlinearity is computed from measurements of the spectral sensitivity of the system, the power spectrum of the imaging system was flattened and its bandwidth broadened. Consequently, the PSF has a narrower axial extent and still lower sidelobe levels. Pulse-echo images acquired with time-stretched chirps as optical modulation have higher axial resolution (64 μm) than those obtained with linear chirps, at the expense of a lower SNR (6.8 dB). Using a linear or time-stretched chirp, the conversion efficiency from optical power to acoustical pressure improved by a factor of 70 or 61, respectively, compared to that obtained with pulsed excitation.

  9. Uncovering the differential molecular basis of adaptive diversity in three Echinochloa leaf transcriptomes.

    PubMed

    Nah, Gyoungju; Im, Ji-Hoon; Kim, Jin-Won; Park, Hae-Rim; Yook, Min-Jung; Yang, Tae-Jin; Fischer, Albert J; Kim, Do-Soon

    2015-01-01

    Echinochloa is a major weed that grows almost everywhere in farmed land. This high prevalence results from its high adaptability to various water conditions, including upland and paddy fields, and its ability to grow in a wide range of climates, ranging from tropical to temperate regions. Three Echinochloa crus-galli accessions (EC-SNU1, EC-SNU2, and EC-SNU3) collected in Korea have shown diversity in their responses to flooding, with EC-SNU1 exhibiting the greatest growth among three accessions. In the search for molecular components underlying adaptive diversity among the three Echinochloa crus-galli accessions, we performed de novo assembly of leaf transcriptomes and investigated the pattern of differentially expressed genes (DEGs). Although the overall composition of the three leaf transcriptomes was well-conserved, the gene expression patterns of particular gene ontology (GO) categories were notably different among the three accessions. Under non-submergence growing conditions, five protein categories (serine/threonine kinase, leucine-rich repeat kinase, signaling-related, glycoprotein, and glycosidase) were significantly (FDR, q < 0.05) enriched in up-regulated DEGs from EC-SNU1. These up-regulated DEGs include major components of signal transduction pathways, such as receptor-like kinase (RLK) and calcium-dependent protein kinase (CDPK) genes, as well as previously known abiotic stress-responsive genes. Our results therefore suggest that diversified gene expression regulation of upstream signaling components conferred the molecular basis of adaptive diversity in Echinochloa crus-galli.

  10. Intestinal transcriptome analysis revealed differential salinity adaptation between two tilapiine species.

    PubMed

    Ronkin, Dana; Seroussi, Eyal; Nitzan, Tali; Doron-Faigenboim, Adi; Cnaani, Avner

    2015-03-01

    Tilapias are a group of freshwater species, which vary in their ability to adapt to high salinity water. Osmotic regulation in fish is conducted mainly in the gills, kidney, and gastrointestinal tract (GIT). The mechanisms involved in ion and water transport through the GIT is not well-characterized, with only a few described complexes. Comparing the transcriptome of the anterior and posterior intestinal sections of a freshwater and saltwater adapted fish by deep-sequencing, we examined the salinity adaptation of two tilapia species: the high salinity-tolerant Oreochromis mossambicus (Mozambique tilapia), and the less salinity-tolerant Oreochromis niloticus (Nile tilapia). This comparative analysis revealed high similarity in gene expression response to salinity change between species in the posterior intestine and large differences in the anterior intestine. Furthermore, in the anterior intestine 68 genes were saltwater up-regulated in one species and down-regulated in the other species (47 genes up-regulated in O. niloticus and down-regulated in O. mossambicus, with 21 genes showing the reverse pattern). Gene ontology (GO) analysis showed a high proportion of transporter and ion channel function among these genes. The results of this study point to a group of genes that differed in their salinity-dependent regulation pattern in the anterior intestine as potentially having a role in the differential salinity tolerance of these two closely related species.

  11. Differential enzyme targeting as an evolutionary adaptation to herbivory in carnivora.

    PubMed

    Birdsey, Graeme M; Lewin, Jackie; Cunningham, Andrew A; Bruford, Michael W; Danpure, Christopher J

    2004-04-01

    Not all members of the order Carnivora are carnivorous. Some are omnivorous, and a few, such as the giant panda, Ailuropoda melanoleuca, are almost exclusively herbivorous. Although a number of adaptations to increased plant-eating are recognized within Carnivora, few have been studied at the molecular level. One molecular adaptation to diet that is spread widely across Mammalia is the differential intracellular targeting of the intermediary metabolic enzyme alanine:glyoxylate aminotransferase (AGT), which tends to be mitochondrial in carnivores, peroxisomal in herbivores, and both mitochondrial and peroxisomal in omnivores. In the present study, we have analyzed the targeting of AGT in Carnivora in relation to species' natural diets. We show not only that there has been an adaptive shift in AGT targeting from the mitochondrion toward the peroxisome as diets have shifted from being mainly carnivorous to ones that are more omnivorous and herbivorous but also that in one lineage, namely that of the giant panda, there is evidence for positive selection pressure at the molecular level on the AGT mitochondrial targeting sequence to decrease its efficiency, thereby allowing more AGT to be targeted to the peroxisomes.

  12. Lower bound for the security of differential phase shift quantum key distribution against a one-pulse-attack

    NASA Astrophysics Data System (ADS)

    Li, Hong-Wei; Yin, Zhen-Qiang; Wang, Shuang; Bao, Wan-Su; Guo, Guang-Can; Han, Zheng-Fu

    2011-10-01

    Quantum key distribution is the art of sharing secret keys between two distant parties, and has attracted a lot of attention due to its unconditional security. Compared with other quantum key distribution protocols, the differential phase shift quantum key distribution protocol has higher efficiency and simpler apparatus. Unfortunately, the unconditional security of differential phase shift quantum key distribution has not been proved. Utilizing the sharp continuity of the von Neuman entropy and some basic inequalities, we estimate the upper bound for the eavesdropper Eve's information. We then prove the lower bound for the security of the differential phase shift quantum key distribution protocol against a one-pulse attack with Devatak—Winter's secret key rate formula.

  13. Blind frequency-resolved optical-gating pulse characterization for quantitative differential multiphoton microscopy.

    PubMed

    Field, Jeffrey J; Durfee, Charles G; Squier, Jeff A

    2010-10-15

    We use a unique multifocal multiphoton microscope to directly characterize the pulse in the focal plane of a high-NA objective using second-harmonic generation frequency-resolved optical gating (FROG). Because of the nature of the optical setup, femtosecond laser pulses of orthogonal polarization states are generated in the focal plane, each acquiring a different spectral dispersion. By applying an additional constraint on the phase extraction algorithm, we simultaneously extract both the gate and probe pulses from a single spectrogram with a FROG error of 0.016. PMID:20967069

  14. Novel image fusion method based on adaptive pulse coupled neural network and discrete multi-parameter fractional random transform

    NASA Astrophysics Data System (ADS)

    Lang, Jun; Hao, Zhengchao

    2014-01-01

    In this paper, we first propose the discrete multi-parameter fractional random transform (DMPFRNT), which can make the spectrum distributed randomly and uniformly. Then we introduce this new spectrum transform into the image fusion field and present a new approach for the remote sensing image fusion, which utilizes both adaptive pulse coupled neural network (PCNN) and the discrete multi-parameter fractional random transform in order to meet the requirements of both high spatial resolution and low spectral distortion. In the proposed scheme, the multi-spectral (MS) and panchromatic (Pan) images are converted into the discrete multi-parameter fractional random transform domains, respectively. In DMPFRNT spectrum domain, high amplitude spectrum (HAS) and low amplitude spectrum (LAS) components carry different informations of original images. We take full advantage of the synchronization pulse issuance characteristics of PCNN to extract the HAS and LAS components properly, and give us the PCNN ignition mapping images which can be used to determine the fusion parameters. In the fusion process, local standard deviation of the amplitude spectrum is chosen as the link strength of pulse coupled neural network. Numerical simulations are performed to demonstrate that the proposed method is more reliable and superior than several existing methods based on Hue Saturation Intensity representation, Principal Component Analysis, the discrete fractional random transform etc.

  15. Switching among pulse-generation regimes in passively mode-locked fibre laser by adaptive filtering

    NASA Astrophysics Data System (ADS)

    Peng, Junsong; Boscolo, Sonia

    2016-04-01

    We show both numerically and experimentally that dispersion management can be realized by manipulating the dispersion of a filter in a passively mode-locked fibre laser. A programmable filter the dispersion of which can be software configured is employed in the laser. Solitons, stretched-pulses, and dissipative solitons can be targeted reliably by controlling the filter transmission function only, while the length of fibres is fixed in the laser. This technique shows remarkable advantages in controlling operation regimes in ultrafast fibre lasers, in contrast to the traditional technique in which dispersion management is achieved by optimizing the relative length of fibres with opposite-sign dispersion. Our versatile ultrafast fibre laser will be attractive for applications requiring different pulse profiles such as in optical signal processing and optical communications.

  16. Aging and longevity of yeast colony populations: metabolic adaptation and differentiation.

    PubMed

    Váchová, Libuše; Palková, Zdena

    2011-10-01

    Yeast multicellular colonies possess several traits that are absent from individual yeasts. These include the ability to synchronize colony population development and adapt its metabolism to different environmental changes, such as nutrient depletion. This, together with cell diversification to cell variants with distinct metabolic and other properties, contributes to the main goal of the colony population: to achieve longevity. In this respect, a benefit to individual cells is subordinated to the benefit to the whole population, exhibiting a kind of altruistic behaviour. For example, some colony cells located at particular positions undergo regulated cell dying and provide components to other cells located in more propitious areas. The enhancement of techniques that enable the in vivo investigation of three-dimensional spatiotemporal colony development may lead to new discoveries on metabolic differentiation and regulation in the near future.

  17. Pulsed electromagnetic fields stimulate osteogenic differentiation in human bone marrow and adipose tissue derived mesenchymal stem cells.

    PubMed

    Ongaro, Alessia; Pellati, Agnese; Bagheri, Leila; Fortini, Cinzia; Setti, Stefania; De Mattei, Monica

    2014-09-01

    Pulsed electromagnetic fields (PEMFs) play a regulatory role on osteoblast activity and are clinically beneficial during fracture healing. Human mesenchymal stem cells (MSCs) derived from different sources have been extensively used in bone tissue engineering. Compared with MSCs isolated from bone marrow (BMSCs), those derived from adipose tissue (ASCs) are easier to obtain and available in larger amounts, although they show a less osteogenic differentiation potential than BMSCs. The hypothesis tested in this study was to evaluate whether PEMFs favor osteogenic differentiation both in BMSCs and in ASCs and to compare the role of PEMFs alone and in combination with the biochemical osteogenic stimulus bone morphogenetic protein (BMP)-2. Early and later osteogenic markers, such as alkaline phosphatase (ALP) activity, osteocalcin levels, and matrix mineralization, were analyzed at different times during osteogenic differentiation. Results showed that PEMFs induced osteogenic differentiation by increasing ALP activity, osteocalcin, and matrix mineralization in both BMSCs and ASCs, suggesting that PEMF activity is maintained during the whole differentiation period. The addition of BMP-2 in PEMF exposed cultures further increased all the osteogenic markers in BMSCs, while in ASCs, the stimulatory role of PEMFs was independent of BMP-2. Our results indicate that PEMFs may stimulate an early osteogenic induction in both BMSCs and ASCs and they suggest PEMFs as a bioactive factor to enhance the osteogenesis of ASCs, which are an attractive cell source for clinical applications. In conclusion, PEMFs may be considered a possible tool to improve autologous cell-based regeneration of bone defects in orthopedics.

  18. 315mJ, 2-micrometers Double-Pulsed Coherent Differential Absorption Lidar Transmitter for Atmospheric CO2 Sensing

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Trieu, Bo; Bai, Yingxin; Koch, Grady; Chen, Songsheng; Petzar, Paul; Singh, Upendra N.; Kavaya, Michael J.; Beyon, Jeffrey

    2010-01-01

    The design of a double pulsed, injection seeded, 2-micrometer compact coherent Differential absorption Lidar (DIAL) transmitter for CO2 sensing is presented. This system is hardened for ground and airborne applications. The design architecture includes three continuous wave lasers which provide controlled on and off line seeding, injection seeded power oscillator and a single amplifier operating in double pass configuration. As the derivative a coherent Doppler wind lidar, this instrument has the added benefit of providing wind information. The active laser material used for this application is a Ho: Tm:YLF crystal operates at the eye-safe wavelength. The 3-meter long folded ring resonator produces energy of 130-mJ (90/40) with a temporal pulse length around 220 nanoseconds and 530 nanosecond pulses for on and off lines respectively. The separation between the two pulses is on the order of 200 microseconds. The line width is in the order of 2.5MHz and the beam quality has an M(sup 2) of 1.1 times diffraction limited beam. A final output energy for a pair of both on and off pulses as high as 315 mJ (190/125) at a repetition rate of 10 Hz is achieved. The operating temperature is set around 20 C for the pump diode lasers and 10 C for the rod. Since the laser design has to meet high-energy as well as high beam quality requirements, close attention is paid to the laser head design to avoid thermal distortion in the rod. A side-pumped configuration is used and heat is removed uniformly by passing coolant through a tube slightly larger than the rod to reduce thermal gradient. This paper also discusses the advantage of using a long upper laser level life time laser crystal for DIAL application. In addition issues related to injection seeding with two different frequencies to achieve a transform limited line width will be presented.

  19. An adaptive differential evolution algorithm with novel mutation and crossover strategies for global numerical optimization.

    PubMed

    Islam, Sk Minhazul; Das, Swagatam; Ghosh, Saurav; Roy, Subhrajit; Suganthan, Ponnuthurai Nagaratnam

    2012-04-01

    Differential evolution (DE) is one of the most powerful stochastic real parameter optimizers of current interest. In this paper, we propose a new mutation strategy, a fitness-induced parent selection scheme for the binomial crossover of DE, and a simple but effective scheme of adapting two of its most important control parameters with an objective of achieving improved performance. The new mutation operator, which we call DE/current-to-gr_best/1, is a variant of the classical DE/current-to-best/1 scheme. It uses the best of a group (whose size is q% of the population size) of randomly selected solutions from current generation to perturb the parent (target) vector, unlike DE/current-to-best/1 that always picks the best vector of the entire population to perturb the target vector. In our modified framework of recombination, a biased parent selection scheme has been incorporated by letting each mutant undergo the usual binomial crossover with one of the p top-ranked individuals from the current population and not with the target vector with the same index as used in all variants of DE. A DE variant obtained by integrating the proposed mutation, crossover, and parameter adaptation strategies with the classical DE framework (developed in 1995) is compared with two classical and four state-of-the-art adaptive DE variants over 25 standard numerical benchmarks taken from the IEEE Congress on Evolutionary Computation 2005 competition and special session on real parameter optimization. Our comparative study indicates that the proposed schemes improve the performance of DE by a large magnitude such that it becomes capable of enjoying statistical superiority over the state-of-the-art DE variants for a wide variety of test problems. Finally, we experimentally demonstrate that, if one or more of our proposed strategies are integrated with existing powerful DE variants such as jDE and JADE, their performances can also be enhanced.

  20. Utilizing hypnosis and ego-state therapy to facilitate healthy adaptive differentiation in the treatment of sexual disorders.

    PubMed

    Lemke, Wendy

    2005-01-01

    Much of the literature focuses on the pathology that falls to the far right of the Watkins (1997) differentiation-dissociation continuum, such as Dissociative Identity Disorder and Dissociative Disorder NOS. Adding a "far left" to this continuum, as well as a construct of what the "far left" looks like, makes apparent the value of healthy adaptive differentiation for those individuals that fall to the "far left" of the spectrum; those who don't differentiate enough. A discussion of sexual dysfunction at this end of the continuum and cases of Hypoactive Sexual Desire Disorder and Vaginismus demonstrate the clinical effectiveness of an approach combining hypnosis and ego-state therapy to facilitate healthy adaptive differentiation.

  1. Electrochemical Removal of Metal Cations from Wastewater Monitored by Differential Pulse Polarography

    ERIC Educational Resources Information Center

    Bruce, Delphine; Kuhn, Alexander; Sojic, Neso

    2004-01-01

    Electrodeposition eliminates wastewater pollutants such as electrochemically active metal cations, with different pulse polarography (DPP) scrutinizing the kinetics of the treatment process. These mechanisms produce qualitative and quantitative data about the removal process, while students appreciate the use of electrochemistry in resolving…

  2. Biomechanical differential equations of variables of the arterial pulse based on vessel wall and blood flow features.

    PubMed

    Bendel, U

    1998-04-01

    A dynamic arterial vessel model with an associated flow resistance is deduced in Laplace-transformed form based on a linear dynamic muscle model and a laminar-instationary blood stream with accompanying parameters (such as elasticity, actin myosin overlap, movement resistances, blood stream resistance and blood mass). In addition, a flow resistance is connected at the outlet of the vessel. With the pulse pressure course as the given input, the Laplace-transformed definition enables, in a clearly arranged manner, the derivation of differential equations of several variables of the arterial pulse process--the changes of blood inflow, outflow, storage flow or volume, of the internal vessel pressure, of the output pressure, of the various pressure differences over the vessel, of the vessel wall tension, of the vessel radius and the vessel wall thickness. The derivations yield the order and the structures of these differential equations. The coefficients of these equations are complicated functions (sums and products) of the smooth-muscle, blood-flow and geometrical parameters. Only in special cases--with an open or the closed vessel at the outlet--are the coefficients simple functions of the vessels parameters.

  3. Anodic Oxidation of Etodolac and its Linear Sweep, Square Wave and Differential Pulse Voltammetric Determination in Pharmaceuticals

    PubMed Central

    Yilmaz, B.; Kaban, S.; Akcay, B. K.

    2015-01-01

    In this study, simple, fast and reliable cyclic voltammetry, linear sweep voltammetry, square wave voltammetry and differential pulse voltammetry methods were developed and validated for determination of etodolac in pharmaceutical preparations. The proposed methods were based on electrochemical oxidation of etodolac at platinum electrode in acetonitrile solution containing 0.1 M lithium perchlorate. The well-defined oxidation peak was observed at 1.03 V. The calibration curves were linear for etodolac at the concentration range of 2.5-50 μg/ml for linear sweep, square wave and differential pulse voltammetry methods, respectively. Intra- and inter-day precision values for etodolac were less than 4.69, and accuracy (relative error) was better than 2.00%. The mean recovery of etodolac was 100.6% for pharmaceutical preparations. No interference was found from three tablet excipients at the selected assay conditions. Developed methods in this study are accurate, precise and can be easily applied to Etol, Tadolak and Etodin tablets as pharmaceutical preparation. PMID:26664057

  4. Electroanalytical characteristics of piribedil and its differential pulse and square wave voltammetric determination in pharmaceuticals and human serum.

    PubMed

    Uslu, Bengi; Ozkan, Sibel A

    2003-03-10

    The electrochemical oxidative behavior of piribedil (PR) was described. It was investigated by cyclic, linear sweep, differential pulse (DPV) and square wave (SWV) voltammetric techniques. The redox behavior of PR was found irreversible. Different parameters were tested to optimize the conditions for the determination of PR. The dependence of intensities of currents and potential on pH, concentration, scan rate, nature of the buffer was investigated. Two sensitive methods for the measurement of PR were described. For analytical purposes, a very well resolved diffusion controlled voltammetric peak was obtained in 0.1 M H(2)SO(4) and pH 5.7 acetate buffer. The determination peaks are obtained at 1.27 and 0.95 V for differential pulse and 1.29 and 0.97 V for SWV in 0.1 M H(2)SO(4) and pH 5.7 acetate buffer, respectively. The linear response was obtained in the ranges of 2 x 10(-6)-1 x 10(-3) M in 0.1 M H(2)SO(4) and 2 x 10(-6)-8 x 10(-4) M in pH 5.7 acetate buffer for both techniques. The proposed techniques were successfully applied to the determination of PR in tablet dosage forms and human serum. Excipients did not interfere in the determination. The necessary statistical validation reveals that the proposed methods are free from significant systematic errors.

  5. Anodic Oxidation of Etodolac and its Linear Sweep, Square Wave and Differential Pulse Voltammetric Determination in Pharmaceuticals.

    PubMed

    Yilmaz, B; Kaban, S; Akcay, B K

    2015-01-01

    In this study, simple, fast and reliable cyclic voltammetry, linear sweep voltammetry, square wave voltammetry and differential pulse voltammetry methods were developed and validated for determination of etodolac in pharmaceutical preparations. The proposed methods were based on electrochemical oxidation of etodolac at platinum electrode in acetonitrile solution containing 0.1 M lithium perchlorate. The well-defined oxidation peak was observed at 1.03 V. The calibration curves were linear for etodolac at the concentration range of 2.5-50 μg/ml for linear sweep, square wave and differential pulse voltammetry methods, respectively. Intra- and inter-day precision values for etodolac were less than 4.69, and accuracy (relative error) was better than 2.00%. The mean recovery of etodolac was 100.6% for pharmaceutical preparations. No interference was found from three tablet excipients at the selected assay conditions. Developed methods in this study are accurate, precise and can be easily applied to Etol, Tadolak and Etodin tablets as pharmaceutical preparation.

  6. On-Sky Tests of a High-Power Pulsed Laser for Sodium Laser Guide Star Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Otarola, Angel; Hickson, Paul; Gagné, Ronald; Bo, Yong; Zuo, Junwei; Xie, Shiyong; Feng, Lu; Rochester, Simon; Budker, Dmitry; Shen, Shixia; Xue, Suijian; Min, Li; Wei, Kai; Boyer, Corinne; Ellerbroek, Brent; Hu, Jingyao; Peng, Qinjun; Xu, Zuyan

    2016-03-01

    We present results of on-sky tests performed in the summer of 2013 to characterize the performance of a prototype high-power pulsed laser for adaptive optics. The laser operates at a pulse repetition rate (PRR) of 600-800Hz, with a 6% duty cycle. Its coupling efficiency was found to be, in the best test case (using 18W of transmitted power), 231±14 photons s-1 sr-1 atom-1 W-1 m2 when circular polarization was employed and 167±17 photons s-1 sr-1 atom-1 W-1 m2 with linear polarization. No improvement was seen when D2b repumping was used, but this is likely due to the relatively large laser guide star (LGS) diameter, typically 10 arcsec or more, which resulted in low irradiance levels. Strong relaxation oscillations were present in the laser output, which have the effect of reducing the coupling efficiency. To better understand the results, a physical modeling was performed using the measured pulse profiles and parameters specific to these tests. The model results, for a 10 arcsec angular size LGS spot, agree well with the observations. When extrapolating the physical model for a sub-arcsecond angular size LGS (typical of what is needed for a successful astronomical guide star), the model predicts that this laser would have a coupling efficiency of 130 photons s-1 sr-1 atom-1 W-1 m2, using circular polarization and D2b repumping, for a LGS diameter of 0.6 arcsec Full Width at Half Maximum (FWHM), and free of relaxation oscillations in the 589 nm laser light.

  7. Extreme cellular adaptations and cell differentiation required by a cyanobacterium for carbonate excavation

    PubMed Central

    Guida, Brandon Scott; Garcia-Pichel, Ferran

    2016-01-01

    Some cyanobacteria, known as euendoliths, excavate and grow into calcium carbonates, with their activity leading to significant marine and terrestrial carbonate erosion and to deleterious effects on coral reef and bivalve ecology. Despite their environmental relevance, the mechanisms by which they can bore have remained elusive and paradoxical, in that, as oxygenic phototrophs, cyanobacteria tend to alkalinize their surroundings, which will encourage carbonate precipitation, not dissolution. Therefore, cyanobacteria must rely on unique adaptations to bore. Studies with the filamentous euendolith, Mastigocoleus testarum, indicated that excavation requires both cellular energy and transcellular calcium transport, mediated by P-type ATPases, but the cellular basis for this phenomenon remains obscure. We present evidence that excavation in M. testarum involves two unique cellular adaptations. Long-range calcium transport is based on active pumping at multiple cells along boring filaments, orchestrated by the preferential localization of calcium ATPases at one cell pole, in a ring pattern, facing the cross-walls, and by repeating this placement and polarity, a pattern that breaks at branching and apical cells. In addition, M. testarum differentiates specialized cells we call calcicytes, that which accumulate calcium at concentrations more than 500-fold those found in other cyanobacteria, concomitantly and drastically lowering photosynthetic pigments and enduring severe cytoplasmatic alkalinization. Calcicytes occur commonly, but not exclusively, in apical parts of the filaments distal to the excavation front. We suggest that calcicytes allow for fast calcium flow at low, nontoxic concentrations through undifferentiated cells by providing buffering storage for excess calcium before final excretion to the outside medium. PMID:27140633

  8. Self-Calibration and Laser Energy Monitor Validations for a Double-Pulsed 2-Micron CO2 Integrated Path Differential Absorption Lidar Application

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Singh, Upendra N.; Petros, Mulugeta; Remus, Ruben; Yu, Jirong

    2015-01-01

    Double-pulsed 2-micron integrated path differential absorption (IPDA) lidar is well suited for atmospheric CO2 remote sensing. The IPDA lidar technique relies on wavelength differentiation between strong and weak absorbing features of the gas normalized to the transmitted energy. In the double-pulse case, each shot of the transmitter produces two successive laser pulses separated by a short interval. Calibration of the transmitted pulse energies is required for accurate CO2 measurement. Design and calibration of a 2-micron double-pulse laser energy monitor is presented. The design is based on an InGaAs pin quantum detector. A high-speed photo-electromagnetic quantum detector was used for laser-pulse profile verification. Both quantum detectors were calibrated using a reference pyroelectric thermal detector. Calibration included comparing the three detection technologies in the single-pulsed mode, then comparing the quantum detectors in the double-pulsed mode. In addition, a self-calibration feature of the 2-micron IPDA lidar is presented. This feature allows one to monitor the transmitted laser energy, through residual scattering, with a single detection channel. This reduces the CO2 measurement uncertainty. IPDA lidar ground validation for CO2 measurement is presented for both calibrated energy monitor and self-calibration options. The calibrated energy monitor resulted in a lower CO2 measurement bias, while self-calibration resulted in a better CO2 temporal profiling when compared to the in situ sensor.

  9. Population-scale sequencing reveals genetic differentiation due to local adaptation in Atlantic herring

    PubMed Central

    Lamichhaney, Sangeet; Barrio, Alvaro Martinez; Rafati, Nima; Sundström, Görel; Rubin, Carl-Johan; Gilbert, Elizabeth R.; Berglund, Jonas; Wetterbom, Anna; Laikre, Linda; Webster, Matthew T.; Grabherr, Manfred; Ryman, Nils; Andersson, Leif

    2012-01-01

    The Atlantic herring (Clupea harengus), one of the most abundant marine fishes in the world, has historically been a critical food source in Northern Europe. It is one of the few marine species that can reproduce throughout the brackish salinity gradient of the Baltic Sea. Previous studies based on few genetic markers have revealed a conspicuous lack of genetic differentiation between geographic regions, consistent with huge population sizes and minute genetic drift. Here, we present a cost-effective genome-wide study in a species that lacks a genome sequence. We first assembled a muscle transcriptome and then aligned genomic reads to the transcripts, creating an “exome assembly,” capturing both exons and flanking sequences. We then resequenced pools of fish from a wide geographic range, including the Northeast Atlantic, as well as different regions in the Baltic Sea, aligned the reads to the exome assembly, and identified 440,817 SNPs. The great majority of SNPs showed no appreciable differences in allele frequency among populations; however, several thousand SNPs showed striking differences, some approaching fixation for different alleles. The contrast between low genetic differentiation at most loci and striking differences at others implies that the latter category primarily reflects natural selection. A simulation study confirmed that the distribution of the fixation index FST deviated significantly from expectation for selectively neutral loci. This study provides insights concerning the population structure of an important marine fish and establishes the Atlantic herring as a model for population genetic studies of adaptation and natural selection. PMID:23134729

  10. Different types of exercise induce differential effects on neuronal adaptations and memory performance.

    PubMed

    Lin, Tzu-Wei; Chen, Shean-Jen; Huang, Tung-Yi; Chang, Chia-Yuan; Chuang, Jih-Ing; Wu, Fong-Sen; Kuo, Yu-Min; Jen, Chauying J

    2012-01-01

    Different exercise paradigms show differential effects on various forms of memory. We hypothesize that the differential effects of exercises on memory performance are caused by different neuroplasticity changes in relevant brain regions in response to different exercise trainings. We examined the effects of treadmill running (TR) and wheel running (WR) on the Pavlovian fear conditioning task that assesses learning and memory performance associated with the amygdala (cued conditioning) and both the amygdala and hippocampus (contextual conditioning). The skeletal muscle citrate synthase activity, an indicator of aerobic capacity, was elevated in rats received 4 w of TR, but not WR. While both TR and WR elevated the contextual conditional response, only TR facilitated the cued conditional response. Using a single-neuron labeling technique, we found that while both TR and MR enlarged the dendritic field and increased the spine density in hippocampal CA3 neurons, only TR showed these effects in basolateral amygdalar neurons. Moreover, both types of exercise upregulated synaptic proteins (i.e., TrkB and SNAP-25) in the hippocampus; however only TR showed similar effects in the amygdala. Injection of K252a, a TrkB kinase inhibitor, in the dorsal hippocampus or basolateral amygdala abolished the exercise-facilitated contextual or cued fear learning and memory performance, respectively, regardless of the types of exercise. In summary, our results supported that different types of exercise affect the performance of learning and memory via BDNF-TrkB signaling and neuroplasticity in specific brain regions. The brain region-specific neuronal adaptations are possibly induced by various levels of intensity/stress elicited by different types of exercise.

  11. Local adaptation along a continuous coastline: prey recruitment drives differentiation in a predatory snail.

    PubMed

    Sanford, Eric; Worth, David J

    2010-03-01

    these snails to succeed in an oceanographic region where the recruitment of alternative, preferred prey is low. More broadly, our results suggest that persistent spatial variation in recruitment and other oceanographically mediated processes may lead to adaptive differentiation among populations of consumers in adjacent coastal regions.

  12. Adaptive optics self-calibration using differential OTF (dOTF)

    NASA Astrophysics Data System (ADS)

    Rodack, Alexander T.; Knight, Justin M.; Codona, Johanan L.; Miller, Kelsey L.; Guyon, Olivier

    2015-09-01

    We demonstrate self-calibration of an adaptive optical system using differential OTF [Codona, JL; Opt. Eng. 0001; 52(9):097105-097105. doi:10.1117/1.OE.52.9.097105]. We use a deformable mirror (DM) along with science camera focal plane images to implement a closed-loop servo that both flattens the DM and corrects for non-common-path aberrations within the telescope. The pupil field modification required for dOTF measurement is introduced by displacing actuators near the edge of the illuminated pupil. Simulations were used to develop methods to retrieve the phase from the complex amplitude dOTF measurements for both segmented and continuous sheet MEMS DMs and tests were performed using a Boston Micromachines continuous sheet DM for verification. We compute the actuator correction updates directly from the phase of the dOTF measurements, reading out displacements and/or slopes at segment and actuator positions. Through simulation, we also explore the effectiveness of these techniques for a variety of photons collected in each dOTF exposure pair.

  13. Processing of pulse oximeter signals using adaptive filtering and autocorrelation to isolate perfusion and oxygenation components

    NASA Astrophysics Data System (ADS)

    Ibey, Bennett; Subramanian, Hariharan; Ericson, Nance; Xu, Weijian; Wilson, Mark; Cote, Gerard L.

    2005-03-01

    A blood perfusion and oxygenation sensor has been developed for in situ monitoring of transplanted organs. In processing in situ data, motion artifacts due to increased perfusion can create invalid oxygenation saturation values. In order to remove the unwanted artifacts from the pulsatile signal, adaptive filtering was employed using a third wavelength source centered at 810nm as a reference signal. The 810 nm source resides approximately at the isosbestic point in the hemoglobin absorption curve where the absorbance of light is nearly equal for oxygenated and deoxygenated hemoglobin. Using an autocorrelation based algorithm oxygenation saturation values can be obtained without the need for large sampling data sets allowing for near real-time processing. This technique has been shown to be more reliable than traditional techniques and proven to adequately improve the measurement of oxygenation values in varying perfusion states.

  14. Development of a 2-micron Pulsed Differential Absorption Lidar for Atmospheric CO2 Concentration Measurement by Direct Detection Technique

    NASA Astrophysics Data System (ADS)

    Yu, J.; Singh, U. N.; Petros, M.; Bai, Y.

    2011-12-01

    Researchers at NASA Langley Research Center are developing a 2-micron Pulsed Differential Absorption Lidar instrument for ground and airborne measurements via direct detection method. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capbility by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement. A key component of the CO2 DIAL system, transceiver, is an existing, airborne ready, robust hardware which can provide 250mJ at 10Hz with double pulse format specifically designed for DIAL instrument. The exact wavelengths of the transceiver are controlled by well defined CW seed laser source to provide the required injection source for generating on-and-off line wavelength pulses sequentially. The compact, rugged, highly reliable transceiver is based on the unique Ho:Tm:YLF high-energy 2-micron pulsed laser technology. All the optical mounts are custom designed and have space heritage. They are designed to be adjustable and lockable and hardened to withstand vibrations that can occur in airborne operation. For the direct detection lidar application, a large primary mirror size is preferred. A 14 inch diameter telescope will be developed for this program. The CO2 DIAL/IPDA system requires many electronic functions to operate. These include diode, RF, seed laser, and PZT drivers; injection seeding detection and control; detector power supplies; and analog inputs to sample various sensors. Under NASA Laser Risk Reduction Program (LRRP), a control unit Compact Laser Electronics (CLE), is developed for the controlling the coherent wind lidar transceiver. Significant modifications and additions are needed to update it for CO2 lidar controls. The data acquisition system was built for ground CO2 measurement demonstration. The software will be updated for

  15. Open-path quantum cascade laser-based system for simultaneous remote sensing of methane, nitrous oxide, and water vapor using chirped-pulse differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Castillo, Paulo; Diaz, Adrian; Thomas, Benjamin; Gross, Barry; Moshary, Fred

    2015-10-01

    Methane and Nitrous Oxide are long-lived greenhouse gases in the atmosphere with significant global warming effects. We report on application of chirped-pulsed quantum cascade lasers (QCLs) to simultaneous measurements of these trace gases in both open-path fence-line and backscatter systems. The intra-pulse thermal frequency chip in a QCL can be time resolved and calibrated to allow for high resolution differential optical absorption spectroscopy over the spectral window of the chip, which for a DFB-QCL can be reach ~2cm-1 for a 500 nsec pulse. The spectral line-shape of the output from these lasers are highly stable from pulse to pulse over long period of time (> 1 day), and the system does not require frequent calibrations.

  16. Observation-driven adaptive differential evolution and its application to accurate and smooth bronchoscope three-dimensional motion tracking.

    PubMed

    Luo, Xiongbiao; Wan, Ying; He, Xiangjian; Mori, Kensaku

    2015-08-01

    This paper proposes an observation-driven adaptive differential evolution algorithm that fuses bronchoscopic video sequences, electromagnetic sensor measurements, and computed tomography images for accurate and smooth bronchoscope three-dimensional motion tracking. Currently an electromagnetic tracker with a position sensor fixed at the bronchoscope tip is commonly used to estimate bronchoscope movements. The large tracking error from directly using sensor measurements, which may be deteriorated heavily by patient respiratory motion and the magnetic field distortion of the tracker, limits clinical applications. How to effectively use sensor measurements for precise and stable bronchoscope electromagnetic tracking remains challenging. We here exploit an observation-driven adaptive differential evolution framework to address such a challenge and boost the tracking accuracy and smoothness. In our framework, two advantageous points are distinguished from other adaptive differential evolution methods: (1) the current observation including sensor measurements and bronchoscopic video images is used in the mutation equation and the fitness computation, respectively and (2) the mutation factor and the crossover rate are determined adaptively on the basis of the current image observation. The experimental results demonstrate that our framework provides much more accurate and smooth bronchoscope tracking than the state-of-the-art methods. Our approach reduces the tracking error from 3.96 to 2.89 mm, improves the tracking smoothness from 4.08 to 1.62 mm, and increases the visual quality from 0.707 to 0.741. PMID:25660001

  17. Differential adaptive changes on serotonin and noradrenaline transporters in a rat model of peripheral neuropathic pain.

    PubMed

    Rojo, Maria Luisa; Rodríguez-Gaztelumendi, Antonio; Pazos, Ángel; Díaz, Álvaro

    2012-05-01

    Serotonin and noradrenaline reuptake inhibitors have shown to produce antinociceptive effects in several animal models of neuropathic pain. In the present work, we have analyzed the density of brain and spinal serotonin and noradrenaline transporters (5-HTT and NAT) in a rat model of neuropathic pain, the spinal nerve ligation (SNL). Quantitative autoradiography revealed a significant decrease in the density of 5-HTT ([(3)H]citalopram binding) at the level of the lumbar spinal cord following 2 weeks of neuropathic surgery (lamina V, -40%: 6.01±0.64 nCi/mg tissue in sham-animals vs 3.59±1.56 in SNL-animals; lamina X, -30%: 9.10±2.00 vs 6.40±1.93 and lamina IX, -22%: 12.01±2.41 vs 9.42±1.58). By contrast, NAT density ([(3)H]nisoxetine binding) was significantly increased (lamina I-II, +34%: 2.20±0.45 vs 2.96±0.65; lamina V, +57%: 1.34±0.28 vs 2.11±0.66; and lamina IX, +58%: 2.39±0.71 vs 3.78±1.10). At supraspinal structures, SNL induced adaptive changes only in the density of 5-HTT (septal nuclei, +33%: 10.18±2.03 vs 13.53±1.14; CA3 field of hippocampus, +18%: 6.94±1.01 vs 8.21±0.81; paraventricular thalamic nucleus, +21%: 15.18±1.88 vs 18.35±2.08; lateral hypothalamic area, +40%: 12.68±1.90 vs 17.8±2.55; ventromedial hypothalamic nuclei, +19%: 7.16±0.92 vs 8.55±0.40; and dorsal raphe nucleus, +15%: 35.22±3.88 vs 40.68±3.11). Thus, we demonstrate, in the SNL model of neuropathic pain, the existence of opposite changes in the spinal expression of 5-HTT (down-regulation) and NAT (up-regulation), and the presence of supraspinal adaptive changes (up-regulation) only on 5-HTT density. These findings may help understanding the pathogeny of neuropathic pain and the differential analgesic action of antidepressants targeting 5-HTT and/or NAT transporters.

  18. ADJUSTABLE DOUBLE PULSE GENERATOR

    DOEpatents

    Gratian, J.W.; Gratian, A.C.

    1961-08-01

    >A modulator pulse source having adjustable pulse width and adjustable pulse spacing is described. The generator consists of a cross coupled multivibrator having adjustable time constant circuitry in each leg, an adjustable differentiating circuit in the output of each leg, a mixing and rectifying circuit for combining the differentiated pulses and generating in its output a resultant sequence of negative pulses, and a final amplifying circuit for inverting and square-topping the pulses. (AEC)

  19. Differential Molecular Responses of Rapeseed Cotyledons to Light and Dark Reveal Metabolic Adaptations toward Autotrophy Establishment

    PubMed Central

    He, Dongli; Damaris, Rebecca N.; Fu, Jinlei; Tu, Jinxing; Fu, Tingdong; Xi, Chen; Yi, Bin; Yang, Pingfang

    2016-01-01

    Photosynthesis competent autotrophy is established during the postgerminative stage of plant growth. Among the multiple factors, light plays a decisive role in the switch from heterotrophic to autotrophic growth. Under dark conditions, the rapeseed hypocotyl extends quickly with an apical hook, and the cotyledon is yellow and folded, and maintains high levels of the isocitrate lyase (ICL). By contrast, in the light, the hypocotyl extends slowly, the cotyledon unfolds and turns green, the ICL content changes in parallel with cotyledon greening. To reveal metabolic adaptations during the establishment of postgerminative autotrophy in rapeseed, we conducted comparative proteomic and metabolomic analyses of the cotyledons of seedlings grown under light versus dark conditions. Under both conditions, the increase in proteases, fatty acid β-oxidation and glyoxylate-cycle related proteins was accompanied by rapid degradation of the stored proteins and lipids with an accumulation of the amino acids. While light condition partially retarded these conversions. Light significantly induced the expression of chlorophyll-binding and photorespiration related proteins, resulting in an increase in reducing-sugars. However, the levels of some chlorophyllide conversion, Calvin-cycle and photorespiration related proteins also accumulated in dark grown cotyledons, implying that the transition from heterotrophy to autotrophy is programmed in the seed rather than induced by light. Various anti-stress systems, e.g., redox related proteins, salicylic acid, proline and chaperones, were employed to decrease oxidative stress, which was mainly derived from lipid oxidation or photorespiration, under both conditions. This study provides a comprehensive understanding of the differential molecular responses of rapeseed cotyledons to light and dark conditions, which will facilitate further study on the complex mechanism underlying the transition from heterotrophy to autotrophy. PMID:27471506

  20. Differential Molecular Responses of Rapeseed Cotyledons to Light and Dark Reveal Metabolic Adaptations toward Autotrophy Establishment.

    PubMed

    He, Dongli; Damaris, Rebecca N; Fu, Jinlei; Tu, Jinxing; Fu, Tingdong; Xi, Chen; Yi, Bin; Yang, Pingfang

    2016-01-01

    Photosynthesis competent autotrophy is established during the postgerminative stage of plant growth. Among the multiple factors, light plays a decisive role in the switch from heterotrophic to autotrophic growth. Under dark conditions, the rapeseed hypocotyl extends quickly with an apical hook, and the cotyledon is yellow and folded, and maintains high levels of the isocitrate lyase (ICL). By contrast, in the light, the hypocotyl extends slowly, the cotyledon unfolds and turns green, the ICL content changes in parallel with cotyledon greening. To reveal metabolic adaptations during the establishment of postgerminative autotrophy in rapeseed, we conducted comparative proteomic and metabolomic analyses of the cotyledons of seedlings grown under light versus dark conditions. Under both conditions, the increase in proteases, fatty acid β-oxidation and glyoxylate-cycle related proteins was accompanied by rapid degradation of the stored proteins and lipids with an accumulation of the amino acids. While light condition partially retarded these conversions. Light significantly induced the expression of chlorophyll-binding and photorespiration related proteins, resulting in an increase in reducing-sugars. However, the levels of some chlorophyllide conversion, Calvin-cycle and photorespiration related proteins also accumulated in dark grown cotyledons, implying that the transition from heterotrophy to autotrophy is programmed in the seed rather than induced by light. Various anti-stress systems, e.g., redox related proteins, salicylic acid, proline and chaperones, were employed to decrease oxidative stress, which was mainly derived from lipid oxidation or photorespiration, under both conditions. This study provides a comprehensive understanding of the differential molecular responses of rapeseed cotyledons to light and dark conditions, which will facilitate further study on the complex mechanism underlying the transition from heterotrophy to autotrophy. PMID:27471506

  1. Mouse embryonic fibroblasts accumulate differentially on titanium surfaces treated with nanosecond laser pulses.

    PubMed

    Radmanesh, Mitra; Ektesabi, Amin M; Wyatt, Rachael A; Crawford, Bryan D; Kiani, Amirkianoosh

    2016-01-01

    Biomaterial engineering, specifically in bone implant and osseointegration, is currently facing a critical challenge regarding the response of cells to foreign objects and general biocompatibility of the materials used in the production of these implants. Using the developing technology of the laser surface treatment, this study investigates the effects of the laser repetition rate (frequency) on cell distribution across the surface of the titanium substrates. The main objective of this research is building a fundamental understanding of how cells interact with treated titanium and how different treatments affect cell accumulation. Cells respond differently to surfaces treated with different frequency lasers. The results of this research identify the influence of frequency on surface topography properties and oxidation of titanium, and their subsequent effects on the pattern of cell accumulation on its surface. Despite increased oxidation in laser-treated regions, the authors observe that fibroblast cells prefer untreated titanium to laser-treated regions, except the regions treated with 25 kHz pulses, which become preferentially colonized after 72 h. PMID:27581527

  2. Determination of para-arsanilic acid with improved diazotization reaction using differential pulse cathodic stripping voltammetry in aqueous system.

    PubMed

    Misni, Marpongahtun; Sathishkumar, Palanivel; Ahamad, Rahmalan; MohdYusoff, Abdull Rahim

    2015-01-01

    Para-arsanilic acid (p-ASA) has been widely used in the poultry industry to promote growth and prevent dysentery. It is excreted unchanged in the manure and released into non-target sites causing organoarsenic pollution risk to the environment and living system. Therefore, simple and effective analytical strategies are demanded for determining the samples that contain p-ASA. However, direct determination of both p-ASA and ortho-arsanilic acid (o-ASA) using differential pulse cathodic stripping voltammetry (DPCSV) gives the similar voltammograms that directly hamper the analysis used by the DPCSV technique. In this study, a method to determine and differentiate p-ASA from o-ASA via diazotization and coupling reaction of the amine groups followed by the direct DPCSV determination of diazo compounds is presented. The diazotization reaction carried out at pH 1.5 and 0 ± 1°C for 10 min showed two reduction peaks in DPCSV at-70 mV and -440 mV vs. Ag/AgCl (KCl 3 M). However, when the diazotization reaction was performed at pH 12.5 and 0 ± 1°C for 40 min, a coloured azo compound was produced and the DPCSV showed only one reduction peak that appeared at -600 mV vs. Ag/AgCl (3 M of KCl). The results of this study show that only p-ASA compound gave a reduction peak, whereas o-ASA compound did not give any peak. The detection limit of p-ASA was found to be 4 × 10(-8 )M. As a result, the proposed electro-analytical technique might be a good candidate to determine and differentiate the p-ASA present in the poultry and environmental samples.

  3. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  4. Self-calibration and laser energy monitor validations for a double-pulsed 2-μm CO2 integrated path differential absorption lidar application.

    PubMed

    Refaat, Tamer F; Singh, Upendra N; Petros, Mulugeta; Remus, Ruben; Yu, Jirong

    2015-08-20

    Double-pulsed 2-μm integrated path differential absorption (IPDA) lidar is well suited for atmospheric CO2 remote sensing. The IPDA lidar technique relies on wavelength differentiation between strong and weak absorbing features of the gas normalized to the transmitted energy. In the double-pulse case, each shot of the transmitter produces two successive laser pulses separated by a short interval. Calibration of the transmitted pulse energies is required for accurate CO2 measurement. Design and calibration of a 2-μm double-pulse laser energy monitor is presented. The design is based on an InGaAs pin quantum detector. A high-speed photoelectromagnetic quantum detector was used for laser-pulse profile verification. Both quantum detectors were calibrated using a reference pyroelectric thermal detector. Calibration included comparing the three detection technologies in the single-pulsed mode, then comparing the quantum detectors in the double-pulsed mode. In addition, a self-calibration feature of the 2-μm IPDA lidar is presented. This feature allows one to monitor the transmitted laser energy, through residual scattering, with a single detection channel. This reduces the CO2 measurement uncertainty. IPDA lidar ground validation for CO2 measurement is presented for both calibrated energy monitor and self-calibration options. The calibrated energy monitor resulted in a lower CO2 measurement bias, while self-calibration resulted in a better CO2 temporal profiling when compared to the in situ sensor.

  5. Prism adaptation magnitude has differential influences on perceptual versus manual responses.

    PubMed

    Striemer, Christopher L; Russell, Karyn; Nath, Priya

    2016-10-01

    Previous research has indicated that rightward prism adaptation can reduce symptoms of spatial neglect following right brain damage. In addition, leftward prism adaptation can create "neglect-like" patterns of performance in healthy adults on tasks that measure attention and spatial biases. Although a great deal of research has focused on which behaviors are influenced by prism adaptation, very few studies have focused directly on how the magnitude of visual shift induced by prisms might be related to the observed aftereffects, or the effects of prisms on measures of attentional and spatial biases. In the current study, we examined these questions by having groups of healthy adult participants complete manual line bisection and landmark tasks prior to and following adaptation to either 8.5° (15 diopter; n = 22) or 17° (30 diopter; n = 25) leftward shifting prisms. Our results demonstrated a significantly larger rightward shift in straight-ahead pointing (a measure of prism aftereffect) following adaptation to 17°, compared to 8.5° leftward shifting prisms. In addition, only 17° leftward shifting prisms resulted in a significant rightward shift in line bisection following adaptation. However, there was a significant change in performance on the landmark task pre- versus post-adaptation in both the 8.5° and 17° leftward shifting prism groups. Interestingly, correlation analyses indicated that changes in straight-ahead pointing pre- versus post-adaptation were positively correlated with changes in performance on the manual line bisection task, but not the landmark task. These data suggest that larger magnitudes of prism adaptation seem to have a greater influence on tasks that require a response with the adapted hand (i.e., line bisection), compared to tasks that only require a perceptual judgment (i.e., the landmark task). In addition, these data provide further evidence that the effects of prisms on manual and perceptual responses are not related to one

  6. Prism adaptation magnitude has differential influences on perceptual versus manual responses.

    PubMed

    Striemer, Christopher L; Russell, Karyn; Nath, Priya

    2016-10-01

    Previous research has indicated that rightward prism adaptation can reduce symptoms of spatial neglect following right brain damage. In addition, leftward prism adaptation can create "neglect-like" patterns of performance in healthy adults on tasks that measure attention and spatial biases. Although a great deal of research has focused on which behaviors are influenced by prism adaptation, very few studies have focused directly on how the magnitude of visual shift induced by prisms might be related to the observed aftereffects, or the effects of prisms on measures of attentional and spatial biases. In the current study, we examined these questions by having groups of healthy adult participants complete manual line bisection and landmark tasks prior to and following adaptation to either 8.5° (15 diopter; n = 22) or 17° (30 diopter; n = 25) leftward shifting prisms. Our results demonstrated a significantly larger rightward shift in straight-ahead pointing (a measure of prism aftereffect) following adaptation to 17°, compared to 8.5° leftward shifting prisms. In addition, only 17° leftward shifting prisms resulted in a significant rightward shift in line bisection following adaptation. However, there was a significant change in performance on the landmark task pre- versus post-adaptation in both the 8.5° and 17° leftward shifting prism groups. Interestingly, correlation analyses indicated that changes in straight-ahead pointing pre- versus post-adaptation were positively correlated with changes in performance on the manual line bisection task, but not the landmark task. These data suggest that larger magnitudes of prism adaptation seem to have a greater influence on tasks that require a response with the adapted hand (i.e., line bisection), compared to tasks that only require a perceptual judgment (i.e., the landmark task). In addition, these data provide further evidence that the effects of prisms on manual and perceptual responses are not related to one

  7. Effects of ecological differentiation on Lotka-Volterra systems for species with behavioral adaptation and variable growth rates.

    PubMed

    Lacitignola, D; Tebaldi, C

    2005-03-01

    We study the properties of a n2-dimensional Lotka-Volterra system describing competing species that include behaviorally adaptive abilities. We indicate as behavioral adaptation a mechanism, based on a kind of learning, which is not viewed in the evolutionary sense but is intended to occur over shorter time scales. We consider a competitive adaptive n species Lotka-Volterra system, n > or = 3, in which one species is made ecologically differentiated with respect to the others by carrying capacity and intrinsic growth rate. The symmetry properties of the system and the existence of a certain class of invariant subspaces allow the introduction of a 7-dimensional reduced model, where n appears as a parameter, which gives full account of existence and stability of equilibria in the complete system. The reduced model is effective also in describing the time-dependent regimes for a large range of parameter values. The case in which one species has a strong ecological advantage (i.e. with a carrying capacity higher than the others), but with a varying growth rate, has been analyzed in detail, and time-dependent behaviors have been investigated in the case of adaptive competition among four species. Relevant questions, as species survival/exclusion, are addressed focusing on the role of adaptation. Interesting forms of species coexistence are found (i.e. competitive stable equilibria, periodic oscillations, strange attractors).

  8. Adapted physical exercise enhances activation and differentiation potential of satellite cells in the skeletal muscle of old mice.

    PubMed

    Cisterna, Barbara; Giagnacovo, Marzia; Costanzo, Manuela; Fattoretti, Patrizia; Zancanaro, Carlo; Pellicciari, Carlo; Malatesta, Manuela

    2016-05-01

    During ageing, a progressive loss of skeletal muscle mass and a decrease in muscle strength and endurance take place, in the condition termed sarcopenia. The mechanisms of sarcopenia are complex and still unclear; however, it is known that muscle atrophy is associated with a decline in the number and/or efficiency of satellite cells, the main contributors to muscle regeneration. Physical exercise proved beneficial in sarcopenia; however, knowledge of the effect of adapted physical exercise on the myogenic properties of satellite cells in aged muscles is limited. In this study the amount and activation state of satellite cells as well as their proliferation and differentiation potential were assessed in situ by morphology, morphometry and immunocytochemistry at light and transmission electron microscopy on 28-month-old mice submitted to adapted aerobic physical exercise on a treadmill. Sedentary age-matched mice served as controls, and sedentary adult mice were used as a reference for an unperturbed control at an age when the capability of muscle regeneration is still high. The effect of physical exercise in aged muscles was further analysed by comparing the myogenic potential of satellite cells isolated from old running and old sedentary mice using an in vitro system that allows observation of the differentiation process under controlled experimental conditions. The results of this ex vivo and in vitro study demonstrated that adapted physical exercise increases the number and activation of satellite cells as well as their capability to differentiate into structurally and functionally correct myotubes (even though the age-related impairment in myotube formation is not fully reversed): this evidence further supports adapted physical exercise as a powerful, non-pharmacological approach to counteract sarcopenia and the age-related deterioration of satellite cell capabilities even at very advanced age.

  9. Cultural adaptations to the differential threats posed by hot versus cold climates.

    PubMed

    Murray, Damian R

    2013-10-01

    Hot and cold climates have posed differential threats to human survival throughout history. Cold temperatures can pose direct threats to survival in themselves, whereas hot temperatures may pose threats indirectly through higher prevalence of infectious disease. These differential threats yield convergent predictions for the relationship between more demanding climates and freedom of expression, but divergent predictions for freedom from discrimination.

  10. Genetic differentiation, hybridization and adaptive divergence in two subspecies of the acorn barnacle Tetraclita japonica in the northwestern Pacific.

    PubMed

    Tsang, Ling Ming; Chan, Benny K K; Ma, Ka Yan; Chu, Ka Hou

    2008-09-01

    Two acorn barnacles, Tetraclita japonica japonica and Tetraclita japonica formosana, have been recently reclassified as two subspecies, because they are morphologically similar and genetically indistinguishable in mitochondrial DNA sequences. The two barnacles are distinguishable by parietes colour and exhibit parapatric distributions, coexisting in Japan, where T. j. formosana is very low in abundance. Here we investigated the genetic differentiation between the subspecies using 209 polymorphic amplified fragment length polymorphism markers and 341 individuals from 12 locations. The subspecies are genetically highly differentiated (phi(CT) = 0.267). Bayesian analysis and principal component analysis indicate the presence of hybrids in T. j.formosana samples from Japan. Strong differentiation between the northern and southern populations of T. j. japonica was revealed, and a break between Taiwan and Okinawa was also found in T. j. formosana. The differentiation between the two taxa at individual loci does not deviate from neutral expectation, suggesting that the oceanographic pattern which restricts larval dispersal is a more important factor than divergent selection in maintaining genetic and phenotypic differentiation. The T. j. formosana in Japan are probably recent migrants from Okinawa, and their presence in Japan may represent a poleward range shift driven by global warming. This promotes hybridization and might lead to a breakdown of the boundary between the subspecies. However, both local adaptation and larval dispersal are crucial in determining the population structure within each subspecies. Our study provides new insights into the interplay of local adaptation and dispersal in determining the distribution and genetic structure of intertidal biota and the biogeography of the northwestern Pacific.

  11. Preconcentration of trace uranium from seawater with solid phase extraction followed by differential pulse polarographic determination in chloroform eluate.

    PubMed

    Dojozan, D; Pournaghi-Azar, M H; Toutounchi-Asr, J

    1998-05-01

    In the present study, an effective method is presented for the separation and preconcentration of uranium (VI) by solid phase extraction (SPE). For this purpose, U(VI) oxinate is formed by the reaction of U(VI) with 8-hydroxyquinoline and adsorbed onto the octylsilane (C-8) SPE cartridge. The analyte is completely eluted with chloroform and determined by differential pulse polarography. The SPE conditions were optimized by evaluating the effective factors such as pH, oxine concentration, type and concentration of buffer and masking agent. By the proposed method a preconcentration factor more than 100 was achieved. The average recovery of uranium (VI) oxinate (0.1 mg l(-1)) was 99.8%. The relative standard deviation was 1.6% for seven replicate determinations of uranyl ion in the solution with a concentration 20 mug l(-1). Some concomitant ions such as Ca(+2), Mg(+2) and Fe(+3) which interfere in extraction or determination process of uranium were masked with EDTA in aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in Caspian Sea and Persian Gulf water samples. PMID:18967134

  12. Molecularly imprinted polymer grafted graphene for simultaneous electrochemical sensing of 4, 4-methylene diphenylamine and aniline by differential pulse voltammetry.

    PubMed

    Chen, Ningning; Chen, Li; Cheng, Yuxiao; Zhao, Kai; Wu, Xiaohong; Xian, Yuezhong

    2015-01-01

    A sensitive and selective electrochemical sensor based on molecular imprinting polymers grafted graphene (MIPs-G) was developed for simultaneous measurement of 4, 4-methylene diphenylamine (MDA) and aniline by differential pulse voltammetry (DPV). MIPs-G was synthesized via free radical polymerization reaction using MDA and 4-vinyl pyridine as template molecule and functional monomer respectively. The obtained nanocomposites were characterized by transmission electron microscope, scanning electron microscope, Fourier transform infrared spectrometry, Raman spectroscopy and thermal gravimetric analysis. After removal template molecules, MIPs-G was used as electrode material for aromatic amines measurements. Due to the high binding affinity towards MDA and the π-π interaction with aniline, the MIPs-G based electrochemical sensor can be used for simultaneous detection of MDA and aniline by DPV. Under the optimized condition, the oxidation potentials for MDA and aniline were observed at 0.62 and 0.72 V, respectively. Moreover, MIPs-G modified glassy carbon electrode shows linear response towards MDA and aniline simultaneously over the range of 1.0 to 15 μM. The MIPs-G based electrochemical sensor has been applied for simultaneous measurement of MDA and aniline in plastic tableware.

  13. Airborne Measurements of CO2 Column Absorption and Range Using a Pulsed Direct-Detection Integrated Path Differential Absorption Lidar

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Riris, Haris; Weaver, Clark J.; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Browell, Edward V.

    2013-01-01

    We report on airborne CO2 column absorption measurements made in 2009 with a pulsed direct-detection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United States. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The lidar measurement statistics were also calculated for each flight as a function of altitude. The optical depth varied nearly linearly with altitude, consistent with calculations based on atmospheric models. The scatter in the optical depth measurements varied with aircraft altitude as expected, and the median measurement precisions for the column varied from 0.9 to 1.2 ppm. The altitude range with the lowest scatter was 810 km, and the majority of measurements for the column within it had precisions between 0.2 and 0.9 ppm.

  14. Differential adaptation of the linear and nonlinear components of the horizontal vestibuloocular reflex in squirrel monkeys

    NASA Technical Reports Server (NTRS)

    Clendaniel, Richard A.; Lasker, David M.; Minor, Lloyd B.; Shelhamer, M. J. (Principal Investigator)

    2002-01-01

    Previous work in squirrel monkeys has demonstrated the presence of linear and nonlinear components to the horizontal vestibuloocular reflex (VOR) evoked by high-acceleration rotations. The nonlinear component is seen as a rise in gain with increasing velocity of rotation at frequencies more than 2 Hz (a velocity-dependent gain enhancement). We have shown that there are greater changes in the nonlinear than linear component of the response after spectacle-induced adaptation. The present study was conducted to determine if the two components of the response share a common adaptive process. The gain of the VOR, in the dark, to sinusoidal stimuli at 4 Hz (peak velocities: 20-150 degrees /s) and 10 Hz (peak velocities: 20 and 100 degrees /s) was measured pre- and postadaptation. Adaptation was induced over 4 h with x0.45 minimizing spectacles. Sum-of-sines stimuli were used to induce adaptation, and the parameters of the stimuli were adjusted to invoke only the linear or both linear and nonlinear components of the response. Preadaptation, there was a velocity-dependent gain enhancement at 4 and 10 Hz. In postadaptation with the paradigms that only recruited the linear component, there was a decrease in gain and a persistent velocity-dependent gain enhancement (indicating adaptation of only the linear component). After adaptation with the paradigm designed to recruit both the linear and nonlinear components, there was a decrease in gain and no velocity-dependent gain enhancement (indicating adaptation of both components). There were comparable changes in the response to steps of acceleration. We interpret these results to indicate that separate processes drive the adaptation of the linear and nonlinear components of the response.

  15. Service differentiated and adaptive CSMA/CA over IEEE 802.15.4 for Cyber-Physical Systems.

    PubMed

    Xia, Feng; Li, Jie; Hao, Ruonan; Kong, Xiangjie; Gao, Ruixia

    2013-01-01

    Cyber-Physical Systems (CPS) that collect, exchange, manage information, and coordinate actions are an integral part of the Smart Grid. In addition, Quality of Service (QoS) provisioning in CPS, especially in the wireless sensor/actuator networks, plays an essential role in Smart Grid applications. IEEE 802.15.4, which is one of the most widely used communication protocols in this area, still needs to be improved to meet multiple QoS requirements. This is because IEEE 802.15.4 slotted Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) employs static parameter configuration without supporting differentiated services and network self-adaptivity. To address this issue, this paper proposes a priority-based Service Differentiated and Adaptive CSMA/CA (SDA-CSMA/CA) algorithm to provide differentiated QoS for various Smart Grid applications as well as dynamically initialize backoff exponent according to traffic conditions. Simulation results demonstrate that the proposed SDA-CSMA/CA scheme significantly outperforms the IEEE 802.15.4 slotted CSMA/CA in terms of effective data rate, packet loss rate, and average delay. PMID:24260021

  16. Service differentiated and adaptive CSMA/CA over IEEE 802.15.4 for Cyber-Physical Systems.

    PubMed

    Xia, Feng; Li, Jie; Hao, Ruonan; Kong, Xiangjie; Gao, Ruixia

    2013-01-01

    Cyber-Physical Systems (CPS) that collect, exchange, manage information, and coordinate actions are an integral part of the Smart Grid. In addition, Quality of Service (QoS) provisioning in CPS, especially in the wireless sensor/actuator networks, plays an essential role in Smart Grid applications. IEEE 802.15.4, which is one of the most widely used communication protocols in this area, still needs to be improved to meet multiple QoS requirements. This is because IEEE 802.15.4 slotted Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) employs static parameter configuration without supporting differentiated services and network self-adaptivity. To address this issue, this paper proposes a priority-based Service Differentiated and Adaptive CSMA/CA (SDA-CSMA/CA) algorithm to provide differentiated QoS for various Smart Grid applications as well as dynamically initialize backoff exponent according to traffic conditions. Simulation results demonstrate that the proposed SDA-CSMA/CA scheme significantly outperforms the IEEE 802.15.4 slotted CSMA/CA in terms of effective data rate, packet loss rate, and average delay.

  17. Service Differentiated and Adaptive CSMA/CA over IEEE 802.15.4 for Cyber-Physical Systems

    PubMed Central

    Gao, Ruixia

    2013-01-01

    Cyber-Physical Systems (CPS) that collect, exchange, manage information, and coordinate actions are an integral part of the Smart Grid. In addition, Quality of Service (QoS) provisioning in CPS, especially in the wireless sensor/actuator networks, plays an essential role in Smart Grid applications. IEEE 802.15.4, which is one of the most widely used communication protocols in this area, still needs to be improved to meet multiple QoS requirements. This is because IEEE 802.15.4 slotted Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) employs static parameter configuration without supporting differentiated services and network self-adaptivity. To address this issue, this paper proposes a priority-based Service Differentiated and Adaptive CSMA/CA (SDA-CSMA/CA) algorithm to provide differentiated QoS for various Smart Grid applications as well as dynamically initialize backoff exponent according to traffic conditions. Simulation results demonstrate that the proposed SDA-CSMA/CA scheme significantly outperforms the IEEE 802.15.4 slotted CSMA/CA in terms of effective data rate, packet loss rate, and average delay. PMID:24260021

  18. Double-pulse 2-μm integrated path differential absorption lidar airborne validation for atmospheric carbon dioxide measurement.

    PubMed

    Refaat, Tamer F; Singh, Upendra N; Yu, Jirong; Petros, Mulugeta; Remus, Ruben; Ismail, Syed

    2016-05-20

    Field experiments were conducted to test and evaluate the initial atmospheric carbon dioxide (CO2) measurement capability of airborne, high-energy, double-pulsed, 2-μm integrated path differential absorption (IPDA) lidar. This IPDA was designed, integrated, and operated at the NASA Langley Research Center on-board the NASA B-200 aircraft. The IPDA was tuned to the CO2 strong absorption line at 2050.9670 nm, which is the optimum for lower tropospheric weighted column measurements. Flights were conducted over land and ocean under different conditions. The first validation experiments of the IPDA for atmospheric CO2 remote sensing, focusing on low surface reflectivity oceanic surface returns during full day background conditions, are presented. In these experiments, the IPDA measurements were validated by comparison to airborne flask air-sampling measurements conducted by the NOAA Earth System Research Laboratory. IPDA performance modeling was conducted to evaluate measurement sensitivity and bias errors. The IPDA signals and their variation with altitude compare well with predicted model results. In addition, off-off-line testing was conducted, with fixed instrument settings, to evaluate the IPDA systematic and random errors. Analysis shows an altitude-independent differential optical depth offset of 0.0769. Optical depth measurement uncertainty of 0.0918 compares well with the predicted value of 0.0761. IPDA CO2 column measurement compares well with model-driven, near-simultaneous air-sampling measurements from the NOAA aircraft at different altitudes. With a 10-s shot average, CO2 differential optical depth measurement of 1.0054±0.0103 was retrieved from a 6-km altitude and a 4-GHz on-line operation. As compared to CO2 weighted-average column dry-air volume mixing ratio of 404.08 ppm, derived from air sampling, IPDA measurement resulted in a value of 405.22±4.15  ppm with 1.02% uncertainty and

  19. Double-pulse 2-μm integrated path differential absorption lidar airborne validation for atmospheric carbon dioxide measurement.

    PubMed

    Refaat, Tamer F; Singh, Upendra N; Yu, Jirong; Petros, Mulugeta; Remus, Ruben; Ismail, Syed

    2016-05-20

    Field experiments were conducted to test and evaluate the initial atmospheric carbon dioxide (CO2) measurement capability of airborne, high-energy, double-pulsed, 2-μm integrated path differential absorption (IPDA) lidar. This IPDA was designed, integrated, and operated at the NASA Langley Research Center on-board the NASA B-200 aircraft. The IPDA was tuned to the CO2 strong absorption line at 2050.9670 nm, which is the optimum for lower tropospheric weighted column measurements. Flights were conducted over land and ocean under different conditions. The first validation experiments of the IPDA for atmospheric CO2 remote sensing, focusing on low surface reflectivity oceanic surface returns during full day background conditions, are presented. In these experiments, the IPDA measurements were validated by comparison to airborne flask air-sampling measurements conducted by the NOAA Earth System Research Laboratory. IPDA performance modeling was conducted to evaluate measurement sensitivity and bias errors. The IPDA signals and their variation with altitude compare well with predicted model results. In addition, off-off-line testing was conducted, with fixed instrument settings, to evaluate the IPDA systematic and random errors. Analysis shows an altitude-independent differential optical depth offset of 0.0769. Optical depth measurement uncertainty of 0.0918 compares well with the predicted value of 0.0761. IPDA CO2 column measurement compares well with model-driven, near-simultaneous air-sampling measurements from the NOAA aircraft at different altitudes. With a 10-s shot average, CO2 differential optical depth measurement of 1.0054±0.0103 was retrieved from a 6-km altitude and a 4-GHz on-line operation. As compared to CO2 weighted-average column dry-air volume mixing ratio of 404.08 ppm, derived from air sampling, IPDA measurement resulted in a value of 405.22±4.15  ppm with 1.02% uncertainty and

  20. Differential Expression of Genes that Control Respiration Contribute to Thermal Adaptation in Redband Trout (Oncorhynchus mykiss gairdneri)

    PubMed Central

    Garvin, Michael R.; Thorgaard, Gary H.; Narum, Shawn R.

    2015-01-01

    Organisms can adapt to local environmental conditions as a plastic response or become adapted through natural selection on genetic variation. The ability to adapt to increased water temperatures will be of paramount importance for many fish species as the climate continues to warm and water resources become limited. Because increased water temperatures will reduce the dissolved oxygen available for fish, we hypothesized that adaptation to low oxygen environments would involve improved respiration through oxidative phosphorylation (OXPHOS). To test this hypothesis, we subjected individuals from two ecologically divergent populations of inland (redband) rainbow trout (Oncorhynchus mykiss gairdneri) with historically different temperature regimes (desert and montane) and their F1 progeny to diel cycles of temperature stress and then examined gene expression data for 80 nuclear- and mitochondrial-encoded OXPHOS subunits that participate in respiration. Of the 80 transcripts, 7 showed ≥ 2-fold difference in expression levels in gill tissue from desert fish under heat stress whereas the montane fish had none and the F1 only had one differentially expressed gene. A structural analysis of the proteins encoded by those genes suggests that the response could coordinate the formation of supercomplexes and oligomers. Supercomplexes may increase the efficiency of respiration because complexes I, III, and IV are brought into close proximity and oligomerization of complex V alters the macrostructure of mitochondria to improve respiration. Significant differences in gene expression patterns in response to heat stress in a common environment indicate that the response was not due to plasticity but had a genetic basis. PMID:25943341

  1. Differential Expression of Genes that Control Respiration Contribute to Thermal Adaptation in Redband Trout (Oncorhynchus mykiss gairdneri).

    PubMed

    Garvin, Michael R; Thorgaard, Gary H; Narum, Shawn R

    2015-05-04

    Organisms can adapt to local environmental conditions as a plastic response or become adapted through natural selection on genetic variation. The ability to adapt to increased water temperatures will be of paramount importance for many fish species as the climate continues to warm and water resources become limited. Because increased water temperatures will reduce the dissolved oxygen available for fish, we hypothesized that adaptation to low oxygen environments would involve improved respiration through oxidative phosphorylation (OXPHOS). To test this hypothesis, we subjected individuals from two ecologically divergent populations of inland (redband) rainbow trout (Oncorhynchus mykiss gairdneri) with historically different temperature regimes (desert and montane) and their F1 progeny to diel cycles of temperature stress and then examined gene expression data for 80 nuclear- and mitochondrial-encoded OXPHOS subunits that participate in respiration. Of the 80 transcripts, 7 showed ≥ 2-fold difference in expression levels in gill tissue from desert fish under heat stress whereas the montane fish had none and the F1 only had one differentially expressed gene. A structural analysis of the proteins encoded by those genes suggests that the response could coordinate the formation of supercomplexes and oligomers. Supercomplexes may increase the efficiency of respiration because complexes I, III, and IV are brought into close proximity and oligomerization of complex V alters the macrostructure of mitochondria to improve respiration. Significant differences in gene expression patterns in response to heat stress in a common environment indicate that the response was not due to plasticity but had a genetic basis.

  2. Locally adapted fish populations maintain small-scale genetic differentiation despite perturbation by a catastrophic flood event

    PubMed Central

    2010-01-01

    Background Local adaptation to divergent environmental conditions can promote population genetic differentiation even in the absence of geographic barriers and hence, lead to speciation. Perturbations by catastrophic events, however, can distort such parapatric ecological speciation processes. Here, we asked whether an exceptionally strong flood led to homogenization of gene pools among locally adapted populations of the Atlantic molly (Poecilia mexicana, Poeciliidae) in the Cueva del Azufre system in southern Mexico, where two strong environmental selection factors (darkness within caves and/or presence of toxic H2S in sulfidic springs) drive the diversification of P. mexicana. Nine nuclear microsatellites as well as heritable female life history traits (both as a proxy for quantitative genetics and for trait divergence) were used as markers to compare genetic differentiation, genetic diversity, and especially population mixing (immigration and emigration) before and after the flood. Results Habitat type (i.e., non-sulfidic surface, sulfidic surface, or sulfidic cave), but not geographic distance was the major predictor of genetic differentiation. Before and after the flood, each habitat type harbored a genetically distinct population. Only a weak signal of individual dislocation among ecologically divergent habitat types was uncovered (with the exception of slightly increased dislocation from the Cueva del Azufre into the sulfidic creek, El Azufre). By contrast, several lines of evidence are indicative of increased flood-induced dislocation within the same habitat type, e.g., between different cave chambers of the Cueva del Azufre. Conclusions The virtual absence of individual dislocation among ecologically different habitat types indicates strong natural selection against migrants. Thus, our current study exemplifies that ecological speciation in this and other systems, in which extreme environmental factors drive speciation, may be little affected by temporary

  3. Adaptation to visual and proprioceptive rearrangement - Origin of the differential effectiveness of active and passive movements

    NASA Technical Reports Server (NTRS)

    Lackner, J. R.

    1977-01-01

    Experiments were conducted to measure and compare the accuracy with which subjects pointed to visual targets before and after an exposure period in which they received systematic proprioceptive misinformation about the locations of visual targets. The crucial factor determining whether adaptation will be elicited is shown to be the presence of a discordance in the positional information being conveyed over two different sensory modalities. Another experiment was carried out to study the effectiveness of active and passive movements in eliciting adaptation when the subjects were exposed to a systematic discordance between the visual and proprioceptive locations of external targets without being permitted sight of their hands. Superiority of active over passive movements in producing adaptation to visual rearrangement is due to the greater accuracy of position sense information about voluntarily moved limbs, partly derived from the contribution of muscle afferent signals.

  4. Asynchronous multilevel adaptive methods for solving partial differential equations on multiprocessors - Performance results

    NASA Technical Reports Server (NTRS)

    Mccormick, S.; Quinlan, D.

    1989-01-01

    The fast adaptive composite grid method (FAC) is an algorithm that uses various levels of uniform grids (global and local) to provide adaptive resolution and fast solution of PDEs. Like all such methods, it offers parallelism by using possibly many disconnected patches per level, but is hindered by the need to handle these levels sequentially. The finest levels must therefore wait for processing to be essentially completed on all the coarser ones. A recently developed asynchronous version of FAC, called AFAC, completely eliminates this bottleneck to parallelism. This paper describes timing results for AFAC, coupled with a simple load balancing scheme, applied to the solution of elliptic PDEs on an Intel iPSC hypercube. These tests include performance of certain processes necessary in adaptive methods, including moving grids and changing refinement. A companion paper reports on numerical and analytical results for estimating convergence factors of AFAC applied to very large scale examples.

  5. An adaptive wavelet stochastic collocation method for irregular solutions of stochastic partial differential equations

    SciTech Connect

    Webster, Clayton G; Zhang, Guannan; Gunzburger, Max D

    2012-10-01

    Accurate predictive simulations of complex real world applications require numerical approximations to first, oppose the curse of dimensionality and second, converge quickly in the presence of steep gradients, sharp transitions, bifurcations or finite discontinuities in high-dimensional parameter spaces. In this paper we present a novel multi-dimensional multi-resolution adaptive (MdMrA) sparse grid stochastic collocation method, that utilizes hierarchical multiscale piecewise Riesz basis functions constructed from interpolating wavelets. The basis for our non-intrusive method forms a stable multiscale splitting and thus, optimal adaptation is achieved. Error estimates and numerical examples will used to compare the efficiency of the method with several other techniques.

  6. 2-Micron Triple-Pulse Integrated Path Differential Absorption Lidar Development for Simultaneous Airborne Column Measurements of Carbon Dioxide and Water Vapor in the Atmosphere

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong

    2016-01-01

    For more than 15 years, NASA Langley Research Center (LaRC) has contributed in developing several 2-micron carbon dioxide active remote sensors using the DIAL technique. Currently, an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar is under development at NASA LaRC. This paper focuses on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of wavelength control, packaging and lidar integration. In addition, receiver development updates will also be presented, including telescope integration, detection systems and data acquisition electronics. Future plan for IPDA lidar system for ground integration, testing and flight validation will be presented.

  7. A New Sensitive Sensor for Simultaneous Differential Pulse Voltammetric Determination of Codeine and Acetaminophen Using a Hydroquinone Derivative and Multiwall Carbon Nanotubes Carbon Paste Electrode

    PubMed Central

    Garazhian, Elahe; Shishehbore, M. Reza

    2015-01-01

    A new sensitive sensor was fabricated for simultaneous determination of codeine and acetaminophen based on 4-hydroxy-2-(triphenylphosphonio)phenolate (HTP) and multiwall carbon nanotubes paste electrode at trace levels. The sensitivity of codeine determination was deeply affected by spiking multiwall carbon nanotubes and a modifier in carbon paste. Electron transfer coefficient, α, catalytic electron rate constant, k, and the exchange current density, j 0, for oxidation of codeine at the HTP-MWCNT-CPE were calculated using cyclic voltammetry. The calibration curve was linear over the range 0.2–844.7 μM with two linear segments, and the detection limit of 0.063 μM of codeine was obtained using differential pulse voltammetry. The modified electrode was separated codeine and acetaminophen signals by differential pulse voltammetry. The modified electrode was applied for the determination of codeine and acetaminophen in biological and pharmaceutical samples with satisfactory results. PMID:25945094

  8. Highly selective differential pulse voltammetric determination of phenazopyridine using MgCr2O4 nanoparticles decorated MWCNTs-modified glassy carbon electrode.

    PubMed

    Ensafi, Ali A; Arashpour, B; Rezaei, B; Allafchian, Ali R

    2013-11-01

    A selective modified glassy carbon electrode based on multiwall carbon nanotubes decorated with MgCr2O4 nanoparticles was fabricated and used for the determination of phenazopyridine using differential pulse voltammetry. The electrochemical response of the modified electrode toward phenazopyridine was characterized by different electrochemical methods including differential pulse voltammetry (DPV), cyclic voltammetry (CV), and impedance spectroscopy. The prepared electrode showed an efficient synergic effect on the oxidation of phenazopyridine at pH 6.0. The oxidation peak current was proportional to the concentration of phenazopyridine from 0.05 to 7.5 μmol L(-1). The detection limit was 0.025 μmol L(-1). The applicability of the method was confirmed with satisfactory results obtained through the assay of phenazopyridine in human plasma, urine samples, and pharmaceuticals.

  9. Using community archetypes to better understand differential community adaptation to wildfire risk.

    PubMed

    Carroll, Matthew; Paveglio, Travis

    2016-06-01

    One of the immediate challenges of wildfire management concerns threats to human safety and property in residential areas adjacent to non-cultivated vegetation. One approach for relieving this problem is to increase human community 'adaptiveness' to deal with the risk and reality of fire in a variety of landscapes. The challenge in creating 'fire-adapted communities' (FACs) is the great diversity in character and make-up of populations at risk from wildfire. This paper outlines a recently developed categorization scheme for Wildland-Urban Interface (WUI) communities based on a larger conceptual approach for understanding how social diversity is likely to influence the creation of FACs. The WUI categorization scheme situates four community archetypes on a continuum that recognizes dynamic change in human community functioning. We use results from the WUI classification scheme to outline key characteristics associated with each archetype and results from recent case studies to demonstrate the diversity across WUI communities. Differences among key characteristics of local social context will likely result in the need for different adaptation strategies to wildfire. While the WUI archetypes described here may not be broadly applicable to other parts of the world, we argue that the conceptual approach and strategies for systematically documenting local influences on wildfire adaptation have potential for broad application.This article is part of the themed issue 'The interaction of fire and mankind'.

  10. Social Support Provisions as Differential Predictors of Adaptive Outcomes in Young Adolescents

    ERIC Educational Resources Information Center

    Warren, Jared S.; Jackson, Yo; Sifers, Sarah K.

    2009-01-01

    Social support provisions were examined in relation to negative life events, adaptive skills, hope, and grade point average in a sample of 103 inner-city youth (ages 11-14). Analyses focused on seven support provisions: social integration, attachment, guidance and information, reliable alliance, reassurance of worth, nurturance, and instrumental…

  11. Using community archetypes to better understand differential community adaptation to wildfire risk.

    PubMed

    Carroll, Matthew; Paveglio, Travis

    2016-06-01

    One of the immediate challenges of wildfire management concerns threats to human safety and property in residential areas adjacent to non-cultivated vegetation. One approach for relieving this problem is to increase human community 'adaptiveness' to deal with the risk and reality of fire in a variety of landscapes. The challenge in creating 'fire-adapted communities' (FACs) is the great diversity in character and make-up of populations at risk from wildfire. This paper outlines a recently developed categorization scheme for Wildland-Urban Interface (WUI) communities based on a larger conceptual approach for understanding how social diversity is likely to influence the creation of FACs. The WUI categorization scheme situates four community archetypes on a continuum that recognizes dynamic change in human community functioning. We use results from the WUI classification scheme to outline key characteristics associated with each archetype and results from recent case studies to demonstrate the diversity across WUI communities. Differences among key characteristics of local social context will likely result in the need for different adaptation strategies to wildfire. While the WUI archetypes described here may not be broadly applicable to other parts of the world, we argue that the conceptual approach and strategies for systematically documenting local influences on wildfire adaptation have potential for broad application.This article is part of the themed issue 'The interaction of fire and mankind'. PMID:27216514

  12. Habituation and adaptation of the vestibuloocular reflex: a model of differential control by the vestibulocerebellum

    NASA Technical Reports Server (NTRS)

    Cohen, H.; Cohen, B.; Raphan, T.; Waespe, W.

    1992-01-01

    We habituated the dominant time constant of the horizontal vestibuloocular reflex (VOR) of rhesus and cynomolgus monkeys by repeated testing with steps of velocity about a vertical axis and adapted the gain of the VOR by altering visual input with magnifying and reducing lenses. After baseline values were established, the nodulus and ventral uvula of the vestibulocerebellum were ablated in two monkeys, and the effects of nodulouvulectomy and flocculectomy on VOR gain adaptation and habituation were compared. The VOR time constant decreased with repeated testing, rapidly at first and more slowly thereafter. The gain of the VOR was unaffected. Massed trials were more effective than distributed trials in producing habituation. Regardless of the schedule of testing, the VOR time constant never fell below the time constant of the semicircular canals (approximately 5 s). This finding indicates that only the slow component of the vestibular response, the component produced by velocity storage, was habituated. In agreement with this, the time constant of optokinetic after-nystagmus (OKAN) was habituated concurrently with the VOR. Average values for VOR habituation were obtained on a per session basis for six animals. The VOR gain was adapted by natural head movements in partially habituated monkeys while they wore x 2.2 magnifying or x 0.5 reducing lenses. Adaptation occurred rapidly and reached about +/- 30%, similar to values obtained using forced rotation. VOR gain adaptation did not cause additional habituation of the time constant. When the VOR gain was reduced in animals with a long VOR time constant, there were overshoots in eye velocity that peaked at about 6-8 s after the onset or end of constant-velocity rotation. These overshoots occurred at times when the velocity storage integrator would have been maximally activated by semicircular canal input. Since the activity generated in the canals is not altered by visual adaptation, this finding indicates that the gain

  13. Differential Codon Adaptation between dsDNA and ssDNA Phages in Escherichia coli

    PubMed Central

    Chithambaram, Shivapriya; Prabhakaran, Ramanandan; Xia, Xuhua

    2014-01-01

    Because phages use their host translation machinery, their codon usage should evolve toward that of highly expressed host genes. We used two indices to measure codon adaptation of phages to their host, rRSCU (the correlation in relative synonymous codon usage [RSCU] between phages and their host) and Codon Adaptation Index (CAI) computed with highly expressed host genes as the reference set (because phage translation depends on host translation machinery). These indices used for this purpose are appropriate only when hosts exhibit little mutation bias, so only phages parasitizing Escherichia coli were included in the analysis. For double-stranded DNA (dsDNA) phages, both rRSCU and CAI decrease with increasing number of transfer RNA genes encoded by the phage genome. rRSCU is greater for dsDNA phages than for single-stranded DNA (ssDNA) phages, and the low rRSCU values are mainly due to poor concordance in RSCU values for Y-ending codons between ssDNA phages and the E. coli host, consistent with the predicted effect of C→T mutation bias in the ssDNA phages. Strong C→T mutation bias would improve codon adaptation in codon families (e.g., Gly) where U-ending codons are favored over C-ending codons (“U-friendly” codon families) by highly expressed host genes but decrease codon adaptation in other codon families where highly expressed host genes favor C-ending codons against U-ending codons (“U-hostile” codon families). It is remarkable that ssDNA phages with increasing C→T mutation bias also increased the usage of codons in the “U-friendly” codon families, thereby achieving CAI values almost as large as those of dsDNA phages. This represents a new type of codon adaptation. PMID:24586046

  14. A novel differential pulse voltammetric (DPV) method for measuring the antioxidant capacity of polyphenols-reducing cupric neocuproine complex.

    PubMed

    Tufan, Ayşe Nur; Baki, Sefa; Güçlü, Kubilay; Özyürek, Mustafa; Apak, Reşat

    2014-07-23

    A novel differential pulse voltammetric (DPV) method is presented, using a chromogenic oxidizing reagent, cupric neocuproine complex (Cu(Nc)2(2+)), for the assessment of antioxidant capacity of polyphenolic compounds (i.e., flavonoids, simple phenolic acids, and hydroxycinnamic acids), ascorbic acid, and real samples for the first time. The electrochemical behavior of the Cu(Nc)2(2+) complex was studied by cyclic voltammetry at a glassy carbon (GC) electrode. The electroanalytical method was based on the reduction of Cu(Nc)2(2+) to Cu(Nc)2(+) by antioxidants and electrochemical detection of the remaining Cu(II)-Nc (unreacted complex), the difference being correlated to antioxidant capacity of the analytes. The calibration curves of individual compounds comprising polyphenolics and vitamin C were constructed, and their response sensitivities and linear concentration ranges were determined. The reagent on the GC electrode retained its reactivity toward antioxidants, and the measured trolox equivalent antioxidant capacity (TEAC) values of various antioxidants suggested that the reactivity of the Cu(II)-Nc reagent is comparable to that of the solution-based spectrophotometric cupric ion reducing antioxidant capacity (CUPRAC) assay. This electroanalytical method better tolerated sample turbidity and provided higher sensitivity (i.e., lower detection limits) in antioxidant determination than the spectrophotometric assay. The proposed method was successfully applied to the measurement of total antioxidant capacity (TAC) in some herbal tea samples such as green tea, sage, marjoram, and alchemilla. Results demonstrated that the proposed voltammetric method has precision and accuracy comparable to those of the spectrophotometric CUPRAC assay.

  15. Electrochemical Investigation of Coenzyme Q10 on Silver Electrode in Ethanol Aqueous Solution and Its Determination Using Differential Pulse Voltammetry.

    PubMed

    Li, Dan; Deng, Wei; Xu, Hu; Sun, Yinxing; Wang, Yuhong; Chen, Shouhui; Ding, Xianting

    2016-08-01

    The electrochemistry reduction of coenzyme Q10 (CoQ10) on silver electrodes has been investigated in mixed solvent containing 95 vol. % ethanol and 5 vol. % water. A combination of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) is employed to explore the mechanism of redox processes of CoQ10 in the presence and absence of oxygen, respectively. It has been proved that the redox reaction of CoQ10 is highly dependent on the oxygen in the solution compared with that of CoQ0, which may be attributed to the isoprenoid side chain effect of CoQ10 Moreover, the effects of experimental variables such as electrolyte component, pH, temperature, and sonication time on the amperometric and potentiometric responses of CoQ10 are presented. The differential pulse voltammetry method has been developed for the quantification of the CoQ10 in the complex samples. Under the optimum conditions, the method is linear over the concentration range of 1.00 × 10(-7) to 1.00 × 10(-3) mol/L (8.63 × 10(-2) to 8.63 × 10(2) mg/kg). The limit of detection (3σ/k) is 3.33 × 10(-8) mol/L (2.88 × 10(-2) mg/kg). The recoveries of the spiked samples are between 91% and 108%. The presented method can be applied to the analysis of CoQ10 in real samples without any pretreatment.

  16. Complex interplay between neutral and adaptive evolution shaped differential genomic background and disease susceptibility along the Italian peninsula

    PubMed Central

    Sazzini, Marco; Gnecchi Ruscone, Guido Alberto; Giuliani, Cristina; Sarno, Stefania; Quagliariello, Andrea; De Fanti, Sara; Boattini, Alessio; Gentilini, Davide; Fiorito, Giovanni; Catanoso, Mariagrazia; Boiardi, Luigi; Croci, Stefania; Macchioni, Pierluigi; Mantovani, Vilma; Di Blasio, Anna Maria; Matullo, Giuseppe; Salvarani, Carlo; Franceschi, Claudio; Pettener, Davide; Garagnani, Paolo; Luiselli, Donata

    2016-01-01

    The Italian peninsula has long represented a natural hub for human migrations across the Mediterranean area, being involved in several prehistoric and historical population movements. Coupled with a patchy environmental landscape entailing different ecological/cultural selective pressures, this might have produced peculiar patterns of population structure and local adaptations responsible for heterogeneous genomic background of present-day Italians. To disentangle this complex scenario, genome-wide data from 780 Italian individuals were generated and set into the context of European/Mediterranean genomic diversity by comparison with genotypes from 50 populations. To maximize possibility of pinpointing functional genomic regions that have played adaptive roles during Italian natural history, our survey included also ~250,000 exomic markers and ~20,000 coding/regulatory variants with well-established clinical relevance. This enabled fine-grained dissection of Italian population structure through the identification of clusters of genetically homogeneous provinces and of genomic regions underlying their local adaptations. Description of such patterns disclosed crucial implications for understanding differential susceptibility to some inflammatory/autoimmune disorders, coronary artery disease and type 2 diabetes of diverse Italian subpopulations, suggesting the evolutionary causes that made some of them particularly exposed to the metabolic and immune challenges imposed by dietary and lifestyle shifts that involved western societies in the last centuries. PMID:27582244

  17. Complex interplay between neutral and adaptive evolution shaped differential genomic background and disease susceptibility along the Italian peninsula.

    PubMed

    Sazzini, Marco; Gnecchi Ruscone, Guido Alberto; Giuliani, Cristina; Sarno, Stefania; Quagliariello, Andrea; De Fanti, Sara; Boattini, Alessio; Gentilini, Davide; Fiorito, Giovanni; Catanoso, Mariagrazia; Boiardi, Luigi; Croci, Stefania; Macchioni, Pierluigi; Mantovani, Vilma; Di Blasio, Anna Maria; Matullo, Giuseppe; Salvarani, Carlo; Franceschi, Claudio; Pettener, Davide; Garagnani, Paolo; Luiselli, Donata

    2016-01-01

    The Italian peninsula has long represented a natural hub for human migrations across the Mediterranean area, being involved in several prehistoric and historical population movements. Coupled with a patchy environmental landscape entailing different ecological/cultural selective pressures, this might have produced peculiar patterns of population structure and local adaptations responsible for heterogeneous genomic background of present-day Italians. To disentangle this complex scenario, genome-wide data from 780 Italian individuals were generated and set into the context of European/Mediterranean genomic diversity by comparison with genotypes from 50 populations. To maximize possibility of pinpointing functional genomic regions that have played adaptive roles during Italian natural history, our survey included also ~250,000 exomic markers and ~20,000 coding/regulatory variants with well-established clinical relevance. This enabled fine-grained dissection of Italian population structure through the identification of clusters of genetically homogeneous provinces and of genomic regions underlying their local adaptations. Description of such patterns disclosed crucial implications for understanding differential susceptibility to some inflammatory/autoimmune disorders, coronary artery disease and type 2 diabetes of diverse Italian subpopulations, suggesting the evolutionary causes that made some of them particularly exposed to the metabolic and immune challenges imposed by dietary and lifestyle shifts that involved western societies in the last centuries. PMID:27582244

  18. [Method of Entirely Parallel Differential Evolution for Model Adaptation in Systems Biology].

    PubMed

    Kozlov, K N; Samsonov, A M; Samsonova, M G

    2015-01-01

    We developed a method of entirely parallel differential evolution for identification of unknown parameters of mathematical models by minimization of the objective function that describes the discrepancy of the model solution and the experimental data. The method is implemented in the free and open source software available on the Internet. The method demonstrated a good performance comparable to the top three methods from CEC-2014 and was successfully applied to several biological problems.

  19. QoS Differential Scheduling in Cognitive-Radio-Based Smart Grid Networks: An Adaptive Dynamic Programming Approach.

    PubMed

    Yu, Rong; Zhong, Weifeng; Xie, Shengli; Zhang, Yan; Zhang, Yun

    2016-02-01

    As the next-generation power grid, smart grid will be integrated with a variety of novel communication technologies to support the explosive data traffic and the diverse requirements of quality of service (QoS). Cognitive radio (CR), which has the favorable ability to improve the spectrum utilization, provides an efficient and reliable solution for smart grid communications networks. In this paper, we study the QoS differential scheduling problem in the CR-based smart grid communications networks. The scheduler is responsible for managing the spectrum resources and arranging the data transmissions of smart grid users (SGUs). To guarantee the differential QoS, the SGUs are assigned to have different priorities according to their roles and their current situations in the smart grid. Based on the QoS-aware priority policy, the scheduler adjusts the channels allocation to minimize the transmission delay of SGUs. The entire transmission scheduling problem is formulated as a semi-Markov decision process and solved by the methodology of adaptive dynamic programming. A heuristic dynamic programming (HDP) architecture is established for the scheduling problem. By the online network training, the HDP can learn from the activities of primary users and SGUs, and adjust the scheduling decision to achieve the purpose of transmission delay minimization. Simulation results illustrate that the proposed priority policy ensures the low transmission delay of high priority SGUs. In addition, the emergency data transmission delay is also reduced to a significantly low level, guaranteeing the differential QoS in smart grid.

  20. Simplified flexible-PON upstream transmission using pulse position modulation at ONU and DSP-enabled soft-combining at OLT for adaptive link budgets.

    PubMed

    Liu, Xiang; Effenberger, Frank; Chand, Naresh

    2015-03-01

    We demonstrate a flexible modulation and detection scheme for upstream transmission in passive optical networks using pulse position modulation at optical network unit, facilitating burst-mode detection with automatic decision threshold tracking, and DSP-enabled soft-combining at optical line terminal. Adaptive receiver sensitivities of -33.1 dBm, -36.6 dBm and -38.3 dBm at a bit error ratio of 10(-4) are respectively achieved for 2.5 Gb/s, 1.25 Gb/s and 625 Mb/s after transmission over a 20-km standard single-mode fiber without any optical amplification.

  1. Differential Cortical Neurotrophin and Cytogenetic Adaptation after Voluntary Exercise in Normal and Amnestic Rats

    PubMed Central

    Hall, Joseph M.; Vetreno, Ryan P.; Savage, Lisa M.

    2013-01-01

    Voluntary exercise (VEx) has profound effects on neural and behavioral plasticity, including recovery of CNS trauma and disease. However, the unique regional cortical adaption to VEx has not been elucidated. In a series of experiments, we first examined whether VEx would restore and retain neurotrophin levels in several cortical regions (frontal cortex [FC], retrosplenial cortex [RSC], occipital cortex [OC]) in an animal model (pyrithiamine-induced thiamine deficiency [PTD]) of the amnestic disorder Wernicke-Korsakoff syndrome. In addition, we assessed the time-dependent effect of VEx to rescue performance on a spontaneous alternation task. Following 2-weeks of VEx or stationary housing conditions (Stat), rats were behaviorally tested and brains were harvested either the day after VEx (24-h) or after an additional two-week period (2-wk). In both control pair-fed (PF) rats and PTD rats, all neurotrophin levels (brain-derived neurotrophic factor [BDNF], nerve growth factor [NGF], and vascular endothelial growth factor [VEGF]) increased at the 24-h period after VEx in the FC and RSC, but not OC. Two-weeks following VEx, BDNF remained elevated in both FC and RSC, whereas NGF remained elevated in only the FC. Interestingly, VEx only recovered cognitive performance in amnestic rats when there was an additional 2-wk adaptation period after VEx. Given this unique temporal profile, Experiment 2 examined the cortical cytogenetic responses in all three cortical regions following a 2-wk adaptation period after VEx. In healthy (PF) rats, VEx increased the survival of progenitor cells in both the FC and RSC, but only increased oligodendrocyte precursor cells in the FC. Furthermore, VEx had a selective effect of only recovering oligodendrocyte precursor cells in the FC in PTD rats. These data reveal the therapeutic potential of exercise to restore cortical plasticity in the amnestic brain, and that the FC is one of the most responsive cortical regions to VEx. PMID:24215977

  2. Laser fusion pulse shape controller

    DOEpatents

    Siebert, Larry D.

    1977-01-01

    An apparatus for controlling the pulse shape, i.e., the pulse duration and intensity pattern, of a pulsed laser system, and which is particularly well adapted for controlling the pellet ignition pulse in a laser-driven fusion reaction system. The apparatus comprises a laser generator for providing an optical control pulse of the shape desired, a pulsed laser triggered by the control pulse, and a plurality of optical Kerr-effect gates serially disposed at the output of the pulsed laser and selectively triggered by the control pulse to pass only a portion of the pulsed laser output generally corresponding in shape to the control pulse.

  3. Differential gene expression of phosphoglyceric kinase (PGK) and hypoxic adaptation in chicken.

    PubMed

    Wang, CunFang; Yuan, CunZhong; Zhang, Lao; Wu, ChangXin; Li, Ning

    2007-06-01

    Four single-nucleotide polymorphisms (SNP) of the Phosphoglyceric Kinase (PGK) gene were discovered based on comparison of the sequences from an altiplano chicken breed (Tibetan chicken) and two lowland breeds (White Leghorn and Shouguang chicken). Gel-shift results indicate that one of these SNPs, an A-->G mutation at position 59 in exon10, is able to bind hypoxia-induced factor-l (HIF-1), functioning as a hypoxia response element (HRE). The mutant gene results in M-->T mutation at position 379 amino acid. The combined activity of this HRE and HIF-1 could increase correspondingly under a hypoxic stimulus. Hypoxia leads to increased death rates of chicken embryos; while the M-->T mutation described herein is prevalent in healthy embryos grown under hypoxic conditions, thus it may represent an adaptation to hypoxia. Fluorescence quantitative reverse transcription PCR results revealed that HIF-1 upregulates the transcript level of the glycolytic enzyme PGK in the brain and skeletal muscle of animals subjected to hypoxia. Thus, a large amount of ATP is produced by increased glycolysis, allowing the organism to meet energy metabolism demands. As such, we believe this SNP to be an adaptation to the external anoxic environment.

  4. Differential gene retention as an evolutionary mechanism to generate biodiversity and adaptation in yeasts.

    PubMed

    Morel, Guillaume; Sterck, Lieven; Swennen, Dominique; Marcet-Houben, Marina; Onesime, Djamila; Levasseur, Anthony; Jacques, Noémie; Mallet, Sandrine; Couloux, Arnaux; Labadie, Karine; Amselem, Joëlle; Beckerich, Jean-Marie; Henrissat, Bernard; Van de Peer, Yves; Wincker, Patrick; Souciet, Jean-Luc; Gabaldón, Toni; Tinsley, Colin R; Casaregola, Serge

    2015-06-25

    The evolutionary history of the characters underlying the adaptation of microorganisms to food and biotechnological uses is poorly understood. We undertook comparative genomics to investigate evolutionary relationships of the dairy yeast Geotrichum candidum within Saccharomycotina. Surprisingly, a remarkable proportion of genes showed discordant phylogenies, clustering with the filamentous fungus subphylum (Pezizomycotina), rather than the yeast subphylum (Saccharomycotina), of the Ascomycota. These genes appear not to be the result of Horizontal Gene Transfer (HGT), but to have been specifically retained by G. candidum after the filamentous fungi-yeasts split concomitant with the yeasts' genome contraction. We refer to these genes as SRAGs (Specifically Retained Ancestral Genes), having been lost by all or nearly all other yeasts, and thus contributing to the phenotypic specificity of lineages. SRAG functions include lipases consistent with a role in cheese making and novel endoglucanases associated with degradation of plant material. Similar gene retention was observed in three other distantly related yeasts representative of this ecologically diverse subphylum. The phenomenon thus appears to be widespread in the Saccharomycotina and argues that, alongside neo-functionalization following gene duplication and HGT, specific gene retention must be recognized as an important mechanism for generation of biodiversity and adaptation in yeasts.

  5. Differential Involvement of the Dentate Gyrus in Adaptive Forgetting in the Rat.

    PubMed

    Joseph, Mickaël Antoine; Fraize, Nicolas; Ansoud-Lerouge, Jennifer; Sapin, Emilie; Peyron, Christelle; Arthaud, Sébastien; Libourel, Paul-Antoine; Parmentier, Régis; Salin, Paul Antoine; Malleret, Gaël

    2015-01-01

    How does the brain discriminate essential information aimed to be stored permanently from information required only temporarily, and that needs to be cleared away for not saturating our precious memory space? Reference Memory (RM) refers to the long-term storage of invariable information whereas Working Memory (WM) depends on the short-term storage of trial-unique information. Previous work has revealed that WM tasks are very sensitive to proactive interference. In order to prevent such interference, irrelevant old memories must be forgotten to give new ones the opportunity to be stabilized. However, unlike memory, physiological processes underlying this adaptive form of forgetting are still poorly understood. Here, we precisely ask what specific brain structure(s) could be responsible for such process to occur. To answer this question, we trained rats in a radial maze using three paradigms, a RM task and two WM tasks involving or not the processing of interference but strictly identical in terms of locomotion or motivation. We showed that an inhibition of the expression of Zif268 and c-Fos, two indirect markers of neuronal activity and synaptic plasticity, was observed in the dentate gyrus of the dorsal hippocampus when processing such interfering previously stored information. Conversely, we showed that inactivating the dentate gyrus impairs both RM and WM, but improves the processing of interference. Altogether, these results strongly suggest for the first time that the dentate gyrus could be a key structure involved in adaptive forgetting. PMID:26528714

  6. Patched based methods for adaptive mesh refinement solutions of partial differential equations

    SciTech Connect

    Saltzman, J.

    1997-09-02

    This manuscript contains the lecture notes for a course taught from July 7th through July 11th at the 1997 Numerical Analysis Summer School sponsored by C.E.A., I.N.R.I.A., and E.D.F. The subject area was chosen to support the general theme of that year`s school which is ``Multiscale Methods and Wavelets in Numerical Simulation.`` The first topic covered in these notes is a description of the problem domain. This coverage is limited to classical PDEs with a heavier emphasis on hyperbolic systems and constrained hyperbolic systems. The next topic is difference schemes. These schemes are the foundation for the adaptive methods. After the background material is covered, attention is focused on a simple patched based adaptive algorithm and its associated data structures for square grids and hyperbolic conservation laws. Embellishments include curvilinear meshes, embedded boundary and overset meshes. Next, several strategies for parallel implementations are examined. The remainder of the notes contains descriptions of elliptic solutions on the mesh hierarchy, elliptically constrained flow solution methods and elliptically constrained flow solution methods with diffusion.

  7. Morphological adaptation with no mitochondrial DNA differentiation in the coastal plain swamp sparrow

    USGS Publications Warehouse

    Greenberg, R.; Cordero, P.J.; Droege, S.; Fleischer, R.C.

    1998-01-01

    We estimated genetic differentiation between morphologically distinct tidal marsh populations of Swamp Sparrows (Melospiza georgiana nigrescens) and the more wide-spread inland populations (M. g. georgiana and M. g. ericrypta). The tidal marsh populations are consistently grayer with more extensive black markings (particularly in the crown), and their bills are larger. These differences are variously shared with other species of salt marsh birds and small mammals. We analyzed mitochondrial DNA sequences (5' end of control region, COII/tlys/ATPase8, and ND2) of Swamp Sparrows and found low levels of genetic variation and no evidence of geographic structure. These results suggest a rapid and recent geographic expansion of Swamp Sparrows from restricted Pleistocene populations. Morphological differentiation has occurred without long-term genetic isolation, suggesting that selection on the divergent traits is intense. The grayer and more melanistic plumage is probably cryptic coloration for foraging on tidal mud, which tends to be grayish as a result of the formation of iron sulfides, rather than iron oxides, under anaerobic conditions.

  8. Differential sampling for fast frequency acquisition via adaptive extended least squares algorithm

    NASA Technical Reports Server (NTRS)

    Kumar, Rajendra

    1987-01-01

    This paper presents a differential signal model along with appropriate sampling techinques for least squares estimation of the frequency and frequency derivatives and possibly the phase and amplitude of a sinusoid received in the presence of noise. The proposed algorithm is recursive in mesurements and thus the computational requirement increases only linearly with the number of measurements. The dimension of the state vector in the proposed algorithm does not depend upon the number of measurements and is quite small, typically around four. This is an advantage when compared to previous algorithms wherein the dimension of the state vector increases monotonically with the product of the frequency uncertainty and the observation period. Such a computational simplification may possibly result in some loss of optimality. However, by applying the sampling techniques of the paper such a possible loss in optimality can made small.

  9. PULSE COUNTER

    DOEpatents

    Trumbo, D.E.

    1959-02-10

    A transistorized pulse-counting circuit adapted for use with nuclear radiation detecting detecting devices to provide a small, light weight portable counter is reported. The small size and low power requirements of the transistor are of particular value in this instance. The circuit provides an adjustable count scale with a single transistor which is triggered by the accumulated charge on a storage capacitor.

  10. Differential pulse anodic voltammetric determination of lithium ions in pharmaceutical formulations using a carbon paste electrode modified with spinel-type manganese oxide.

    PubMed

    Teixeira, Marcos F S; Moraes, Fernando C; Cavalheiro, Eder T G; Bocchi, Nerilso

    2003-03-10

    The use of the differential pulse voltammetry for the determination of lithium ions in pharmaceutical samples using a carbon paste electrode modified with spinel-type manganese oxide has been examined. The best voltammetric response was reached for a modified electrode in borate buffer solution of pH 9.0 and submitted to a scan rate of 5 mV s(-1) and a pulse amplitude of 50 mV. This electroanalytical procedure was able to determine lithium ions in the concentration range of 8.0 x 10(-5)-1.0 x 10(-2) mol l(-1) even in the presence of several alkali metals (1.0 x 10(-3) mol l(-1)) with a detection limit of 7.1 x 10(-7) mol l(-1). Rapidity, precise and good selectivity were also found for the determination of lithium ions in pharmaceutical formulations.

  11. Differential pathways regulating innate and adaptive antitumor immune responses by particulate and soluble yeast-derived β-glucans

    PubMed Central

    Qi, Chunjian; Cai, Yihua; Gunn, Lacey; Ding, Chuanlin; Li, Bing; Kloecker, Goetz; Qian, Keqing; Vasilakos, John; Saijo, Shinobu; Iwakura, Yoichiro; Yannelli, John R.

    2011-01-01

    β-glucans have been reported to function as a potent adjuvant to stimulate innate and adaptive immune responses. However, β-glucans from different sources are differential in their structure, conformation, and thus biologic activity. Different preparations of β-glucans, soluble versus particulate, further complicate their mechanism of action. Here we show that yeast-derived particulate β-glucan activated dendritic cells (DCs) and macrophages via a C-type lectin receptor dectin-1 pathway. Activated DCs by particulate β-glucan promoted Th1 and cytotoxic T-lymphocyte priming and differentiation in vitro. Treatment of orally administered yeast-derived particulate β-glucan elicited potent antitumor immune responses and drastically down-regulated immunosuppressive cells, leading to the delayed tumor progression. Deficiency of the dectin-1 receptor completely abrogated particulate β-glucan–mediated antitumor effects. In contrast, yeast-derived soluble β-glucan bound to DCs and macrophages independent of the dectin-1 receptor and did not activate DCs. Soluble β-glucan alone had no therapeutic effect but significantly augmented antitumor monoclonal antibody-mediated therapeutic efficacy via a complement activation pathway but independent of dectin-1 receptor. These findings reveal the importance of different preparations of β-glucans in the adjuvant therapy and allow for the rational design of immunotherapeutic protocols usable in clinical trials. PMID:21531981

  12. Differential pathways regulating innate and adaptive antitumor immune responses by particulate and soluble yeast-derived β-glucans.

    PubMed

    Qi, Chunjian; Cai, Yihua; Gunn, Lacey; Ding, Chuanlin; Li, Bing; Kloecker, Goetz; Qian, Keqing; Vasilakos, John; Saijo, Shinobu; Iwakura, Yoichiro; Yannelli, John R; Yan, Jun

    2011-06-23

    β-glucans have been reported to function as a potent adjuvant to stimulate innate and adaptive immune responses. However, β-glucans from different sources are differential in their structure, conformation, and thus biologic activity. Different preparations of β-glucans, soluble versus particulate, further complicate their mechanism of action. Here we show that yeast-derived particulate β-glucan activated dendritic cells (DCs) and macrophages via a C-type lectin receptor dectin-1 pathway. Activated DCs by particulate β-glucan promoted Th1 and cytotoxic T-lymphocyte priming and differentiation in vitro. Treatment of orally administered yeast-derived particulate β-glucan elicited potent antitumor immune responses and drastically down-regulated immunosuppressive cells, leading to the delayed tumor progression. Deficiency of the dectin-1 receptor completely abrogated particulate β-glucan-mediated antitumor effects. In contrast, yeast-derived soluble β-glucan bound to DCs and macrophages independent of the dectin-1 receptor and did not activate DCs. Soluble β-glucan alone had no therapeutic effect but significantly augmented antitumor monoclonal antibody-mediated therapeutic efficacy via a complement activation pathway but independent of dectin-1 receptor. These findings reveal the importance of different preparations of β-glucans in the adjuvant therapy and allow for the rational design of immunotherapeutic protocols usable in clinical trials.

  13. Differential Mitochondrial Adaptation in Primary Vascular Smooth Muscle Cells from a Diabetic Rat Model.

    PubMed

    Keller, Amy C; Knaub, Leslie A; McClatchey, P Mason; Connon, Chelsea A; Bouchard, Ron; Miller, Matthew W; Geary, Kate E; Walker, Lori A; Klemm, Dwight J; Reusch, Jane E B

    2016-01-01

    Diabetes affects more than 330 million people worldwide and causes elevated cardiovascular disease risk. Mitochondria are critical for vascular function, generate cellular reactive oxygen species (ROS), and are perturbed by diabetes, representing a novel target for therapeutics. We hypothesized that adaptive mitochondrial plasticity in response to nutrient stress would be impaired in diabetes cellular physiology via a nitric oxide synthase- (NOS-) mediated decrease in mitochondrial function. Primary smooth muscle cells (SMCs) from aorta of the nonobese, insulin resistant rat diabetes model Goto-Kakizaki (GK) and the Wistar control rat were exposed to high glucose (25 mM). At baseline, significantly greater nitric oxide evolution, ROS production, and respiratory control ratio (RCR) were observed in GK SMCs. Upon exposure to high glucose, expression of phosphorylated eNOS, uncoupled respiration, and expression of mitochondrial complexes I, II, III, and V were significantly decreased in GK SMCs (p < 0.05). Mitochondrial superoxide increased with high glucose in Wistar SMCs (p < 0.05) with no change in the GK beyond elevated baseline concentrations. Baseline comparisons show persistent metabolic perturbations in a diabetes phenotype. Overall, nutrient stress in GK SMCs caused a persistent decline in eNOS and mitochondrial function and disrupted mitochondrial plasticity, illustrating eNOS and mitochondria as potential therapeutic targets. PMID:27034743

  14. QoS Differential Scheduling in Cognitive-Radio-Based Smart Grid Networks: An Adaptive Dynamic Programming Approach.

    PubMed

    Yu, Rong; Zhong, Weifeng; Xie, Shengli; Zhang, Yan; Zhang, Yun

    2016-02-01

    As the next-generation power grid, smart grid will be integrated with a variety of novel communication technologies to support the explosive data traffic and the diverse requirements of quality of service (QoS). Cognitive radio (CR), which has the favorable ability to improve the spectrum utilization, provides an efficient and reliable solution for smart grid communications networks. In this paper, we study the QoS differential scheduling problem in the CR-based smart grid communications networks. The scheduler is responsible for managing the spectrum resources and arranging the data transmissions of smart grid users (SGUs). To guarantee the differential QoS, the SGUs are assigned to have different priorities according to their roles and their current situations in the smart grid. Based on the QoS-aware priority policy, the scheduler adjusts the channels allocation to minimize the transmission delay of SGUs. The entire transmission scheduling problem is formulated as a semi-Markov decision process and solved by the methodology of adaptive dynamic programming. A heuristic dynamic programming (HDP) architecture is established for the scheduling problem. By the online network training, the HDP can learn from the activities of primary users and SGUs, and adjust the scheduling decision to achieve the purpose of transmission delay minimization. Simulation results illustrate that the proposed priority policy ensures the low transmission delay of high priority SGUs. In addition, the emergency data transmission delay is also reduced to a significantly low level, guaranteeing the differential QoS in smart grid. PMID:25910254

  15. The adaptive significance of population differentiation in offspring size of the least killifish, Heterandria formosa

    PubMed Central

    Leips, Jeff; Helen Rodd, F; Travis, Joseph

    2013-01-01

    We tested the hypothesis that density-dependent competition influences the evolution of offspring size. We studied two populations of the least killifish (Heterandria formosa) that differ dramatically in population density; these populations are genetically differentiated for offspring size, and females from both populations produce larger offspring when they experience higher social densities. To look at the influences of population of origin and relative body size on competitive ability, we held females from the high-density population at two different densities to create large and small offspring with the same genetic background. We measured the competitive ability of those offspring in mesocosms that contained either pure or mixed population treatments at either high or low density. High density increased competition, which was most evident in greatly reduced individual growth rates. Larger offspring from the high-density population significantly delayed the onset of maturity of fish from the low-density population. From our results, we infer that competitive conditions in nature have contributed to the evolution of genetically based interpopulation differences in offspring size as well as plasticity in offspring size in response to conspecific density. PMID:23610636

  16. Differentiation of a Vero cell adapted porcine epidemic diarrhea virus from Korean field strains by restriction fragment length polymorphism analysis of ORF 3.

    PubMed

    Song, D S; Yang, J S; Oh, J S; Han, J H; Park, B K

    2003-05-16

    A porcine epidemic diarrhea virus (PEDV) designated DR13 was isolated in Vero cells and serially passaged by level 100. The virus was titrated at regular intervals of the passage level. Open reading frame (ORF) 3 sequences of the virus at passage levels 20, 40, 60, 80, and 100 were aligned and compared using a computer software program. Suitability of the restriction fragment length polymorphism (RFLP) analysis for differentiating the virus from other Korean field strains was investigated. The DR13 field isolate was successively adapted in Vero cells as observed through polymerase chain reaction (PCR) and titration of the virus. RFLP analysis identified change in cleavage sites of HindIII and Xho II from passage levels 75 and 90, respectively; these RFLP patterns of ORF 3 differentiated the Vero cell-adapted virus from its parent strain, DR13, and 12 other strains of PEDV studied. The cell adapted DR13 was tested for its pathogenicity and immunogenicity in piglets and pregnant sows. The results indicated that cell adapted DR13 revealed reduced pathogenicity and induced protective immune response in pigs. Differentiation between highly Vero cell-adapted virus and wild-type virus could be the marker of adaptation to cell culture and a valuable tool for epidemiologic studies of PEDV infections. The results of this study supported that the cell attenuated virus could be applied as a marker vaccine candidate against PEDV infection.

  17. Differential Haemoparasite Intensity between Black Sparrowhawk (Accipiter melanoleucus) Morphs Suggests an Adaptive Function for Polymorphism

    PubMed Central

    Lei, Bonnie; Amar, Arjun; Koeslag, Ann; Gous, Tertius A.; Tate, Gareth J.

    2013-01-01

    Recent research suggests that genes coding for melanin based colouration may have pleiotropic properties, in particular conveying raised immune function. Thus adaptive function of polymorphism may be associated with parasite resistance. The black sparrowhawk Accipiter melanoleucus is a polymorphic raptor with two morphs. Over most of its range the light morph is commonest, however within the recently colonised Western Cape of South Africa the dark morph predominates. The species breeds in winter throughout South Africa, however unlike in the rest of the species' South African range, the Western Cape experiences a winter rainfall regime, where arthropod vectors which transmit haematozoan parasites may be more abundant. We hypothesise that the higher frequency of dark morph birds in this region may be due to their improved parasite resistance, which enables them to cope with higher parasite pressure. If so, we predict that dark morph black sparrowhawks would have lower parasite burdens than light morph birds. Within our population the prevalence of the two most common haematozoan parasites was high, with 72% of adults infected with Haemoproteus nisi and 59% of adults infected with Leucocytozoon toddi. We found no difference in prevalence for either parasite between adult morphs, or between chicks of different parental morphs. However, within adults infected with H. nisi, infection intensity was significantly higher in light morphs than dark morphs. This suggests that dark morphs have lower parasite loads than light morphs due to resistance rather than morph-specific habitat exploitation. Greater resistance to Haemoproteus parasites may therefore be one of the mechanisms through which dark morph black sparrowhawks have a selective advantage in this region and may explain why they are most common in our study area. In other regions, the cost to benefit ratio may be in favour of the light morph, where parasites are less abundant or virulent. PMID:24391707

  18. Triple-Pulsed Two-Micron Integrated Path Differential Absorption Lidar: A New Active Remote Sensing Capability with Path to Space

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Refaat, Tamer F.; Petros, Mulugeta; Yu, Jirong

    2015-01-01

    The two-micron wavelength is suitable for monitoring atmospheric water vapor and carbon dioxide, the two most dominant greenhouse gases. Recent advances in 2-micron laser technology paved the way for constructing state-of-the-art lidar transmitters for active remote sensing applications. In this paper, a new triple-pulsed 2-micron integrated path differential absorption lidar is presented. This lidar is capable of measuring either two species or single specie with two different weighting functions, simultaneously and independently. Development of this instrument is conducted at NASA Langley Research Center. Instrument scaling for projected future space missions will be discussed.

  19. Triple-Pulsed Two-Micron Integrated Path Differential Absorption Lidar: A New Active Remote Sensing Capability with Path to Space

    NASA Astrophysics Data System (ADS)

    Singh, Upendra N.; Refaat, Tamer F.; Petros, Mulugeta; Yu, Jirong

    2016-06-01

    The two-micron wavelength is suitable for monitoring atmospheric water vapor and carbon dioxide, the two most dominant greenhouse gases. Recent advances in 2-μm laser technology paved the way for constructing state-of-the-art lidar transmitters for active remote sensing applications. In this paper, a new triple-pulsed 2-μm integrated path differential absorption lidar is presented. This lidar is capable of measuring either two species or single specie with two different weighting functions, simultaneously and independently. Development of this instrument is conducted at NASA Langley Research Center. Instrument scaling for projected future space missions will be discussed.

  20. Adaptations to endosymbiosis in a cnidarian-dinoflagellate association: differential gene expression and specific gene duplications.

    PubMed

    Ganot, Philippe; Moya, Aurélie; Magnone, Virginie; Allemand, Denis; Furla, Paola; Sabourault, Cécile

    2011-07-01

    Trophic endosymbiosis between anthozoans and photosynthetic dinoflagellates forms the key foundation of reef ecosystems. Dysfunction and collapse of symbiosis lead to bleaching (symbiont expulsion), which is responsible for the severe worldwide decline of coral reefs. Molecular signals are central to the stability of this partnership and are therefore closely related to coral health. To decipher inter-partner signaling, we developed genomic resources (cDNA library and microarrays) from the symbiotic sea anemone Anemonia viridis. Here we describe differential expression between symbiotic (also called zooxanthellate anemones) or aposymbiotic (also called bleached) A. viridis specimens, using microarray hybridizations and qPCR experiments. We mapped, for the first time, transcript abundance separately in the epidermal cell layer and the gastrodermal cells that host photosynthetic symbionts. Transcriptomic profiles showed large inter-individual variability, indicating that aposymbiosis could be induced by different pathways. We defined a restricted subset of 39 common genes that are characteristic of the symbiotic or aposymbiotic states. We demonstrated that transcription of many genes belonging to this set is specifically enhanced in the symbiotic cells (gastroderm). A model is proposed where the aposymbiotic and therefore heterotrophic state triggers vesicular trafficking, whereas the symbiotic and therefore autotrophic state favors metabolic exchanges between host and symbiont. Several genetic pathways were investigated in more detail: i) a key vitamin K-dependant process involved in the dinoflagellate-cnidarian recognition; ii) two cnidarian tissue-specific carbonic anhydrases involved in the carbon transfer from the environment to the intracellular symbionts; iii) host collagen synthesis, mostly supported by the symbiotic tissue. Further, we identified specific gene duplications and showed that the cnidarian-specific isoform was also up-regulated both in the

  1. Adaptations to Endosymbiosis in a Cnidarian-Dinoflagellate Association: Differential Gene Expression and Specific Gene Duplications

    PubMed Central

    Magnone, Virginie; Allemand, Denis; Furla, Paola; Sabourault, Cécile

    2011-01-01

    Trophic endosymbiosis between anthozoans and photosynthetic dinoflagellates forms the key foundation of reef ecosystems. Dysfunction and collapse of symbiosis lead to bleaching (symbiont expulsion), which is responsible for the severe worldwide decline of coral reefs. Molecular signals are central to the stability of this partnership and are therefore closely related to coral health. To decipher inter-partner signaling, we developed genomic resources (cDNA library and microarrays) from the symbiotic sea anemone Anemonia viridis. Here we describe differential expression between symbiotic (also called zooxanthellate anemones) or aposymbiotic (also called bleached) A. viridis specimens, using microarray hybridizations and qPCR experiments. We mapped, for the first time, transcript abundance separately in the epidermal cell layer and the gastrodermal cells that host photosynthetic symbionts. Transcriptomic profiles showed large inter-individual variability, indicating that aposymbiosis could be induced by different pathways. We defined a restricted subset of 39 common genes that are characteristic of the symbiotic or aposymbiotic states. We demonstrated that transcription of many genes belonging to this set is specifically enhanced in the symbiotic cells (gastroderm). A model is proposed where the aposymbiotic and therefore heterotrophic state triggers vesicular trafficking, whereas the symbiotic and therefore autotrophic state favors metabolic exchanges between host and symbiont. Several genetic pathways were investigated in more detail: i) a key vitamin K–dependant process involved in the dinoflagellate-cnidarian recognition; ii) two cnidarian tissue-specific carbonic anhydrases involved in the carbon transfer from the environment to the intracellular symbionts; iii) host collagen synthesis, mostly supported by the symbiotic tissue. Further, we identified specific gene duplications and showed that the cnidarian-specific isoform was also up-regulated both in the

  2. Column CO2 Measurement From an Airborne Solid-State Double-Pulsed 2-Micron Integrated Path Differential Absorption Lidar

    NASA Technical Reports Server (NTRS)

    Singh, U. N.; Yu, J.; Petros, M.; Refaat, T. F.; Remus, R.; Fay, J.; Reithmaier, K.

    2014-01-01

    NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micrometers IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  3. Novel Adaptive Optics concepts : wavefront sensing with sodium laser guide stars at Extemely Large Telescopes and simultaneous differential imaging

    NASA Astrophysics Data System (ADS)

    Kellner, Stephan Albert

    2005-12-01

    Since more than 15 years, Adaptive Optics (AO) is a proven concept to reach diffraction limited imaging at modern astronomical telescopes. In the case of next generation telescopes (Extremely Large Telescopes (ELTs)) with aperture diameters of up to 100m, sodium laser guide star based multi-conjugated-AO systems will be a basic requirement to exploit their full capability in terms of resolution and light concentration. A drawback of such an approach emerges in the finite distance and vertical extent of the sodium beacon in the mesosphere with respect to the telescope. This induces effects such as perspective elongation, where conventional wavefront sensing mechanisms will fail. Although several engineering concepts are under development to counteract these constraints at the cost of overall light efficiency and increased system complexity, this thesis proposes a novel kind of wavefront sensing technique to overcome the imposed limitations in a more natural way. The sensing technique is composed of two independently working sensors, a reflective rod and a mask with circular slits, each a representative of a novel wavefront sensor class, the so called z-invariant and Inverse Bessel Beam technique. Both are discussed in this thesis with a focus on the Inverse Bessel Beam technique. The latter is compared to alternative concepts such as temporal gating, with respect to the photon efficiency. Furthermore, the reflective rod was tested for its feasibility in laboratory conditions and in a more realistic environment at the William Herschel Telescope (WHT) at La Palma. With this test run its sensing principle has been verified. A novel technique already intensively used at 8m class telescopes is Simultaneous Differential Imaging. The direct detection of giant extra-solar planets is and will be a major science driver for galactic astronomy in the coming years. Modern telescope facilities such as the VLT reach, by means of adaptive optics, potentially the capability in terms

  4. Determination of Silver(I) by Differential Pulse Voltammetry Using a Glassy Carbon Electrode Modified with Synthesized N-(2-Aminoethyl)-4,4′-Bipyridine

    PubMed Central

    Radulescu, Maria-Cristina; Chira, Ana; Radulescu, Medeea; Bucur, Bogdan; Bucur, Madalina Petruta; Radu, Gabriel Lucian

    2010-01-01

    A new modified glassy carbon electrode (GCE) based on a synthesized N-(2-aminoethyl)-4,4′-bipyridine (ABP) was developed for the determination of Ag(I) by differential pulse voltammetry (DPV). ABP was covalently immobilized on GC electrodes surface using 4-nitrobenzendiazonium (4-NBD) and glutaraldehyde (GA). The Ag(I) ions were preconcentrated by chemical interaction with bipyridine under a negative potential (−0.6 V); then the reduced ions were oxidized by differential pulse voltammetry and a peak was observed at 0.34 V. The calibration curve was linear in the concentration range from 0.05 μM to 1 μM Ag(I) with a detection limit of 0.025 μM and RSD = 3.6%, for 0.4 μM Ag(I). The presence of several common ions in more than 125-fold excess had no effect on the determination of Ag(I). The developed sensor was applied to the determination of Ag(I) in water samples using a standard addition method. PMID:22163530

  5. Accessible bioprinting: adaptation of a low-cost 3D-printer for precise cell placement and stem cell differentiation.

    PubMed

    Reid, John A; Mollica, Peter A; Johnson, Garett D; Ogle, Roy C; Bruno, Robert D; Sachs, Patrick C

    2016-06-01

    The precision and repeatability offered by computer-aided design and computer-numerically controlled techniques in biofabrication processes is quickly becoming an industry standard. However, many hurdles still exist before these techniques can be used in research laboratories for cellular and molecular biology applications. Extrusion-based bioprinting systems have been characterized by high development costs, injector clogging, difficulty achieving small cell number deposits, decreased cell viability, and altered cell function post-printing. To circumvent the high-price barrier to entry of conventional bioprinters, we designed and 3D printed components for the adaptation of an inexpensive 'off-the-shelf' commercially available 3D printer. We also demonstrate via goal based computer simulations that the needle geometries of conventional commercially standardized, 'luer-lock' syringe-needle systems cause many of the issues plaguing conventional bioprinters. To address these performance limitations we optimized flow within several microneedle geometries, which revealed a short tapered injector design with minimal cylindrical needle length was ideal to minimize cell strain and accretion. We then experimentally quantified these geometries using pulled glass microcapillary pipettes and our modified, low-cost 3D printer. This systems performance validated our models exhibiting: reduced clogging, single cell print resolution, and maintenance of cell viability without the use of a sacrificial vehicle. Using this system we show the successful printing of human induced pluripotent stem cells (hiPSCs) into Geltrex and note their retention of a pluripotent state 7 d post printing. We also show embryoid body differentiation of hiPSC by injection into differentiation conducive environments, wherein we observed continuous growth, emergence of various evaginations, and post-printing gene expression indicative of the presence of all three germ layers. These data demonstrate an

  6. Accessible bioprinting: adaptation of a low-cost 3D-printer for precise cell placement and stem cell differentiation.

    PubMed

    Reid, John A; Mollica, Peter A; Johnson, Garett D; Ogle, Roy C; Bruno, Robert D; Sachs, Patrick C

    2016-06-01

    The precision and repeatability offered by computer-aided design and computer-numerically controlled techniques in biofabrication processes is quickly becoming an industry standard. However, many hurdles still exist before these techniques can be used in research laboratories for cellular and molecular biology applications. Extrusion-based bioprinting systems have been characterized by high development costs, injector clogging, difficulty achieving small cell number deposits, decreased cell viability, and altered cell function post-printing. To circumvent the high-price barrier to entry of conventional bioprinters, we designed and 3D printed components for the adaptation of an inexpensive 'off-the-shelf' commercially available 3D printer. We also demonstrate via goal based computer simulations that the needle geometries of conventional commercially standardized, 'luer-lock' syringe-needle systems cause many of the issues plaguing conventional bioprinters. To address these performance limitations we optimized flow within several microneedle geometries, which revealed a short tapered injector design with minimal cylindrical needle length was ideal to minimize cell strain and accretion. We then experimentally quantified these geometries using pulled glass microcapillary pipettes and our modified, low-cost 3D printer. This systems performance validated our models exhibiting: reduced clogging, single cell print resolution, and maintenance of cell viability without the use of a sacrificial vehicle. Using this system we show the successful printing of human induced pluripotent stem cells (hiPSCs) into Geltrex and note their retention of a pluripotent state 7 d post printing. We also show embryoid body differentiation of hiPSC by injection into differentiation conducive environments, wherein we observed continuous growth, emergence of various evaginations, and post-printing gene expression indicative of the presence of all three germ layers. These data demonstrate an

  7. Low intensity pulsed ultrasound (LIPUS) influences the multilineage differentiation of mesenchymal stem and progenitor cell lines through ROCK-Cot/Tpl2-MEK-ERK signaling pathway.

    PubMed

    Kusuyama, Joji; Bandow, Kenjiro; Shamoto, Mitsuo; Kakimoto, Kyoko; Ohnishi, Tomokazu; Matsuguchi, Tetsuya

    2014-04-11

    Mesenchymal stem cells (MSCs) are pluripotent cells that can differentiate into multilineage cell types, including adipocytes and osteoblasts. Mechanical stimulus is one of the crucial factors in regulating MSC differentiation. However, it remains unknown how mechanical stimulus affects the balance between adipogenesis and osteogenesis. Low intensity pulsed ultrasound (LIPUS) therapy is a clinical application of mechanical stimulus and facilitates bone fracture healing. Here, we applied LIPUS to adipogenic progenitor cell and MSC lines to analyze how multilineage cell differentiation was affected. We found that LIPUS suppressed adipogenic differentiation of both cell types, represented by impaired lipid droplet appearance and decreased gene expression of peroxisome proliferator-activated receptor γ2 (Pparg2) and fatty acid-binding protein 4 (Fabp4). LIPUS also down-regulated the phosphorylation level of peroxisome proliferator-activated receptor γ2 protein, inhibiting its transcriptional activity. In contrast, LIPUS promoted osteogenic differentiation of the MSC line, characterized by increased cell calcification as well as inductions of runt-related transcription factor 2 (Runx2) and Osteocalcin mRNAs. LIPUS induced phosphorylation of cancer Osaka thyroid oncogene/tumor progression locus 2 (Cot/Tpl2) kinase, which was essential for the phosphorylation of mitogen-activated kinase kinase 1 (MEK1) and p44/p42 extracellular signal-regulated kinases (ERKs). Notably, effects of LIPUS on both adipogenesis and osteogenesis were prevented by a Cot/Tpl2-specific inhibitor. Furthermore, effects of LIPUS on MSC differentiation as well as Cot/Tpl2 phosphorylation were attenuated by the inhibition of Rho-associated kinase. Taken together, these results indicate that mechanical stimulus with LIPUS suppresses adipogenesis and promotes osteogenesis of MSCs through Rho-associated kinase-Cot/Tpl2-MEK-ERK signaling pathway. PMID:24550383

  8. Circuit Motifs for Contrast-Adaptive Differentiation in Early Sensory Systems: The Role of Presynaptic Inhibition and Short-Term Plasticity

    PubMed Central

    Zhang, Danke; Wu, Si; Rasch, Malte J.

    2015-01-01

    In natural signals, such as the luminance value across of a visual scene, abrupt changes in intensity value are often more relevant to an organism than intensity values at other positions and times. Thus to reduce redundancy, sensory systems are specialized to detect the times and amplitudes of informative abrupt changes in the input stream rather than coding the intensity values at all times. In theory, a system that responds transiently to fast changes is called a differentiator. In principle, several different neural circuit mechanisms exist that are capable of responding transiently to abrupt input changes. However, it is unclear which circuit would be best suited for early sensory systems, where the dynamic range of the natural input signals can be very wide. We here compare the properties of different simple neural circuit motifs for implementing signal differentiation. We found that a circuit motif based on presynaptic inhibition (PI) is unique in a sense that the vesicle resources in the presynaptic site can be stably maintained over a wide range of stimulus intensities, making PI a biophysically plausible mechanism to implement a differentiator with a very wide dynamical range. Moreover, by additionally considering short-term plasticity (STP), differentiation becomes contrast adaptive in the PI-circuit but not in other potential neural circuit motifs. Numerical simulations show that the behavior of the adaptive PI-circuit is consistent with experimental observations suggesting that adaptive presynaptic inhibition might be a good candidate neural mechanism to achieve differentiation in early sensory systems. PMID:25723493

  9. Circuit motifs for contrast-adaptive differentiation in early sensory systems: the role of presynaptic inhibition and short-term plasticity.

    PubMed

    Zhang, Danke; Wu, Si; Rasch, Malte J

    2015-01-01

    In natural signals, such as the luminance value across of a visual scene, abrupt changes in intensity value are often more relevant to an organism than intensity values at other positions and times. Thus to reduce redundancy, sensory systems are specialized to detect the times and amplitudes of informative abrupt changes in the input stream rather than coding the intensity values at all times. In theory, a system that responds transiently to fast changes is called a differentiator. In principle, several different neural circuit mechanisms exist that are capable of responding transiently to abrupt input changes. However, it is unclear which circuit would be best suited for early sensory systems, where the dynamic range of the natural input signals can be very wide. We here compare the properties of different simple neural circuit motifs for implementing signal differentiation. We found that a circuit motif based on presynaptic inhibition (PI) is unique in a sense that the vesicle resources in the presynaptic site can be stably maintained over a wide range of stimulus intensities, making PI a biophysically plausible mechanism to implement a differentiator with a very wide dynamical range. Moreover, by additionally considering short-term plasticity (STP), differentiation becomes contrast adaptive in the PI-circuit but not in other potential neural circuit motifs. Numerical simulations show that the behavior of the adaptive PI-circuit is consistent with experimental observations suggesting that adaptive presynaptic inhibition might be a good candidate neural mechanism to achieve differentiation in early sensory systems.

  10. Differential pulse adsorption voltammetry for determination of procaine hydrochloride at a pumice modified carbon paste electrode in pharmaceutical preparations and urine.

    PubMed

    Wang, Cheng Yin; Hu, Xiao Ya; Jin, Gen Di; Leng, Zong Zhou

    2002-08-22

    Procaine hydrochloride was determined by the differential pulse voltammetry (DPV) using a 6% (m/m) pumice modified carbon paste electrode in 1.25 x 10(-3) mol x l(-1) KH(2)PO(4) and Na(2)HPO(4) buffer solution (pH 6.88, 25 degrees C). The anodic peak potential used was +0.980 V (vs. SCE). A good linear relationship was realized between the anodic peak current and procaine concentration in the range of 9.0 x 10(-7)-2.6 x 10(-5) mol x l(-1) with the detection limit of 5.0 x 10(-8) mol x l(-1). The recovery was 95.2-104.8% with the relative standard deviation of 3.2% (n=10). The pharmaceutical preparations, procaine hydrochloride injection and the urine samples were determined with the desirable results.

  11. Determination of inorganic ionic mercury down to 5x10(-14) mol l(-1) by differential-pulse anodic stripping voltammetry.

    PubMed

    Meyer, S; Scholz, F; Trittler, R

    1996-09-01

    A new method is described for the reliable and ultrasensitive determination of inorganic ionic mercury, using differential-pulse anodic stripping voltammetry on a glassy carbon electrode. It has been possible to determine mercury down to a concentration of 5x10(-14) mol l(-1) (the lowest detection limit ever reported for a voltammetric method). This success was achieved by using a thiocyanate electrolyte and relatively long deposition times. The mercury ions are stabilized in the solution by the formation of strong thiocyanate complexes. This leads to a highly reproducible cathodic plating and anodic dissolution of mercury. A speciation analysis allowing to distinguish between dissolved atomic and ionic mercury in water is possible. PMID:15048362

  12. Hydrodynamic voltammetry at tubular electrodes-III Determination of traces of bismuth by differential-pulse anodic-stripping voltammetry at a glassy-carbon tubular electrode with in situ mercury plating.

    PubMed

    Zhen, W; Qiang, C

    1987-07-01

    An equation for the current in differential-pulse anodic-stripping voltammetry at tubular electrodes is derived. Application of a glassy-carbon tubular electrode to determination of traces of bismuth in environmental water samples by differential-pulse anodic-stripping voltammetry is described. In hydrochloric acid medium, the stripping peak current is proportional to the concentration of bismuth in the range 2-100 ng/ml, with a deposition time of 3-10 min. The detection limit is 0.5 ng/ml. PMID:18964381

  13. Pulse transient hot strip technique adapted for slab sample geometry to study anisotropic thermal transport properties of μm-thin crystalline films.

    PubMed

    Ma, Y; Gustavsson, J S; Haglund, A; Gustavsson, M; Gustafsson, S E

    2014-04-01

    A new method based on the adaptation of the Pulse Transient Hot Strip technique to slab sample geometry has been developed for studying thermal conductivity and thermal diffusivity of anisotropic thin film materials (<50 μm) with thermal conductivity in the 0.01-100 W/mK range, deposited on thin substrates (i.e., wafers). Strength of this technique is that it provides a well-controlled thermal probing depth, making it possible to probe a predetermined depth of the sample layer and thereby avoiding the influence from material(s) deeper down in the sample. To verify the technique a series of measurements were conducted on a y-cut single crystal quartz wafer. A Hot Strip sensor (32-μm wide, 3.2-mm long) was deposited along two orthogonal crystallographic (x- and z-) directions and two independent pulse transients were recorded. Thereafter, the data was fitted to our theoretical model, and the anisotropic thermal transport properties were determined. Using a thermal probing depth of only 30 μm, we obtained a thermal conductivity along the perpendicular (parallel) direction to the z-, i.e., optic axis of 6.48 (11.4) W/mK, and a thermal diffusivity of 3.62 (6.52) mm(2)/s. This yields a volumetric specific heat of 1.79 MJ/mK. These values agree well with tabulated data on bulk crystalline quartz supporting the accuracy of the technique, and the obtained standard deviation of less than 2.7% demonstrates the precision of this new measurement technique.

  14. Optimization of A 2-Micron Laser Frequency Stabilization System for a Double-Pulse CO2 Differential Absorption Lidar

    NASA Technical Reports Server (NTRS)

    Chen, Songsheng; Yu, Jirong; Bai, Yingsin; Koch, Grady; Petros, Mulugeta; Trieu, Bo; Petzar, Paul; Singh, Upendra N.; Kavaya, Michael J.; Beyon, Jeffrey

    2010-01-01

    A carbon dioxide (CO2) Differential Absorption Lidar (DIAL) for accurate CO2 concentration measurement requires a frequency locking system to achieve high frequency locking precision and stability. We describe the frequency locking system utilizing Frequency Modulation (FM), Phase Sensitive Detection (PSD), and Proportional Integration Derivative (PID) feedback servo loop, and report the optimization of the sensitivity of the system for the feed back loop based on the characteristics of a variable path-length CO2 gas cell. The CO2 gas cell is characterized with HITRAN database (2004). The method can be applied for any other frequency locking systems referring to gas absorption line.

  15. High-throughput and sensitive particle counting by a novel microfluidic differential resistive pulse sensor with multidetecting channels and a common reference channel.

    PubMed

    Song, Yongxin; Yang, Jiandong; Pan, Xinxiang; Li, Dongqing

    2015-02-01

    High-throughput particle counting by a differential resistive pulse sensing method in a microfluidic chip is presented in this paper. A sensitive differential microfluidic sensor with multiple detecting channels and one common reference channel was devised. To test the particle counting performance of this chip, an experimental system which consists of the microfluidic chip, electric resistors, an amplification circuit, a LabView based data acquisition device was developed. The influence of the common reference channel on the S/N of particle detection was investigated. The relationship between the hydraulic pressure drop applied across the detecting channel and the counting throughput was experimentally obtained. The experimental results show that the reference channel designed in this work can improve the S/N by ten times, thus enabling sensitive high-throughput particle counting. Because of the greatly improved S/N, the sensing gate with a size of 25 × 50 × 10 μm (W × L × H) in our chips can detect and count particles larger than 1.5 μm in diameter. The counting throughput increases with the increase in the flowing velocity of the sample solution. An average throughput of 7140/min under a flow rate of 10 μL/min was achieved. Comparing with other methods, the structure of the chip and particle detecting mechanism reported in this paper is simple and sensitive, and does not have the crosstalking problem. Counting throughput can be adjusted simply by changing the number of the detecting channels.

  16. An adaptive neuro fuzzy inference system controlled space cector pulse width modulation based HVDC light transmission system under AC fault conditions

    NASA Astrophysics Data System (ADS)

    Ajay Kumar, M.; Srikanth, N. V.

    2014-03-01

    In HVDC Light transmission systems, converter control is one of the major fields of present day research works. In this paper, fuzzy logic controller is utilized for controlling both the converters of the space vector pulse width modulation (SVPWM) based HVDC Light transmission systems. Due to its complexity in the rule base formation, an intelligent controller known as adaptive neuro fuzzy inference system (ANFIS) controller is also introduced in this paper. The proposed ANFIS controller changes the PI gains automatically for different operating conditions. A hybrid learning method which combines and exploits the best features of both the back propagation algorithm and least square estimation method is used to train the 5-layer ANFIS controller. The performance of the proposed ANFIS controller is compared and validated with the fuzzy logic controller and also with the fixed gain conventional PI controller. The simulations are carried out in the MATLAB/SIMULINK environment. The results reveal that the proposed ANFIS controller is reducing power fluctuations at both the converters. It also improves the dynamic performance of the test power system effectively when tested for various ac fault conditions.

  17. Sensitivities of germinating spores and carvacrol-adapted vegetative cells and spores of Bacillus cereus to nisin and pulsed-electric-field treatment.

    PubMed

    Pol, I E; van Arendonk, W G; Mastwijk, H C; Krommer, J; Smid, E J; Moezelaar, R

    2001-04-01

    Treatment of Bacillus cereus spores with nisin and/or pulsed-electric-field (PEF) treatment did not lead to direct inactivation of the spores or increased heat sensitivity as a result of sublethal damage. In contrast, germinating spores were found to be sensitive to PEF treatment. Nisin treatment was more efficient than PEF treatment for inactivating germinating spores. PEF resistance was lost after 50 min of germination, and not all germinated spores could be inactivated. Nisin, however, was able to inactivate the germinating spores to the same extent as heat treatment. Resistance to nisin was lost immediately when the germination process started. A decrease in the membrane fluidity of vegetative cells caused by incubation in the presence of carvacrol resulted in a dramatic increase in the sensitivity to nisin. On the other hand, inactivation by PEF treatment or by a combination of nisin and PEF treatments did not change after adaptation to carvacrol. Spores grown in the presence of carvacrol were not susceptible to nisin and/or PEF treatment in any way. PMID:11282623

  18. In vitro effects of low-intensity pulsed ultrasound stimulation on the osteogenic differentiation of human alveolar bone-derived mesenchymal stem cells for tooth tissue engineering.

    PubMed

    Lim, Kitaek; Kim, Jangho; Seonwoo, Hoon; Park, Soo Hyun; Choung, Pill-Hoon; Chung, Jong Hoon

    2013-01-01

    Ultrasound stimulation produces significant multifunctional effects that are directly relevant to alveolar bone formation, which is necessary for periodontal healing and regeneration. We focused to find out effects of specific duty cycles and the percentage of time that ultrasound is being generated over one on/off pulse period, under ultrasound stimulation. Low-intensity pulsed ultrasound ((LIPUS) 1 MHz) with duty cycles of 20% and 50% was used in this study, and human alveolar bone-derived mesenchymal stem cells (hABMSCs) were treated with an intensity of 50 mW/cm(2) and exposure time of 10 min/day. hABMSCs exposed at duty cycles of 20% and 50% had similar cell viability (O.D.), which was higher (*P < 0.05) than that of control cells. The alkaline phosphatase (ALP) was significantly enhanced at 1 week with LIPUS treatment in osteogenic cultures as compared to control. Gene expressions showed significantly higher expression levels of CD29, CD44, COL1, and OCN in the hABMSCs under LIPUS treatment when compared to control after two weeks of treatment. The effects were partially controlled by LIPUS treatment, indicating that modulation of osteogenesis in hABMSCs was related to the specific stimulation. Furthermore, mineralized nodule formation was markedly increased after LIPUS treatment than that seen in untreated cells. Through simple staining methods such as Alizarin red and von Kossa staining, calcium deposits generated their highest levels at about 3 weeks. These results suggest that LIPUS could enhance the cell viability and osteogenic differentiation of hABMSCs, and could be part of effective treatment methods for clinical applications.

  19. Local adaptation and oceanographic connectivity patterns explain genetic differentiation of a marine diatom across the North Sea–Baltic Sea salinity gradient

    PubMed Central

    Sjöqvist, C; Godhe, A; Jonsson, P R; Sundqvist, L; Kremp, A

    2015-01-01

    Drivers of population genetic structure are still poorly understood in marine micro-organisms. We exploited the North Sea–Baltic Sea transition for investigating the seascape genetics of a marine diatom, Skeletonema marinoi. Eight polymorphic microsatellite loci were analysed in 354 individuals from ten locations to analyse population structure of the species along a 1500-km-long salinity gradient ranging from 3 to 30 psu. To test for salinity adaptation, salinity reaction norms were determined for sets of strains originating from three different salinity regimes of the gradient. Modelled oceanographic connectivity was compared to directional relative migration by correlation analyses to examine oceanographic drivers. Population genetic analyses showed distinct genetic divergence of a low-salinity Baltic Sea population and a high-salinity North Sea population, coinciding with the most evident physical dispersal barrier in the area, the Danish Straits. Baltic Sea populations displayed reduced genetic diversity compared to North Sea populations. Growth optima of low salinity isolates were significantly lower than those of strains from higher native salinities, indicating local salinity adaptation. Although the North Sea–Baltic Sea transition was identified as a barrier to gene flow, migration between Baltic Sea and North Sea populations occurred. However, the presence of differentiated neutral markers on each side of the transition zone suggests that migrants are maladapted. It is concluded that local salinity adaptation, supported by oceanographic connectivity patterns creating an asymmetric migration pattern between the Baltic Sea and the North Sea, determines genetic differentiation patterns in the transition zone. PMID:25892181

  20. Local adaptation and oceanographic connectivity patterns explain genetic differentiation of a marine diatom across the North Sea-Baltic Sea salinity gradient.

    PubMed

    Sjöqvist, C; Godhe, A; Jonsson, P R; Sundqvist, L; Kremp, A

    2015-06-01

    Drivers of population genetic structure are still poorly understood in marine micro-organisms. We exploited the North Sea-Baltic Sea transition for investigating the seascape genetics of a marine diatom, Skeletonema marinoi. Eight polymorphic microsatellite loci were analysed in 354 individuals from ten locations to analyse population structure of the species along a 1500-km-long salinity gradient ranging from 3 to 30 psu. To test for salinity adaptation, salinity reaction norms were determined for sets of strains originating from three different salinity regimes of the gradient. Modelled oceanographic connectivity was compared to directional relative migration by correlation analyses to examine oceanographic drivers. Population genetic analyses showed distinct genetic divergence of a low-salinity Baltic Sea population and a high-salinity North Sea population, coinciding with the most evident physical dispersal barrier in the area, the Danish Straits. Baltic Sea populations displayed reduced genetic diversity compared to North Sea populations. Growth optima of low salinity isolates were significantly lower than those of strains from higher native salinities, indicating local salinity adaptation. Although the North Sea-Baltic Sea transition was identified as a barrier to gene flow, migration between Baltic Sea and North Sea populations occurred. However, the presence of differentiated neutral markers on each side of the transition zone suggests that migrants are maladapted. It is concluded that local salinity adaptation, supported by oceanographic connectivity patterns creating an asymmetric migration pattern between the Baltic Sea and the North Sea, determines genetic differentiation patterns in the transition zone.

  1. Electroanalytical determination of donepezil HCl in tablets and human serum by differential pulse and osteryoung square wave voltammetry at a glassy carbon electrode.

    PubMed

    Golcu, A; Ozkan, S A

    2006-09-01

    Donepezil hydrochloride (DNP) is used for the treatment of mild to moderate dementia of the Alzheimer's type. The voltammetric behavior of DNP was studied at a glassy carbon electrode using cyclic, linear sweep, differential pulse (DPV) and square-wave (OSWV) voltammetric techniques. DNP exhibited irreversible anodic waves within the pH range 1.80 and 9.00 in different supporting electrolytes. The peak was characterized as being irreversible and diffusion-controlled. The possible mechanism of the oxidation process is discussed. The current-concentration plot was rectilinear over the range from 1 x 10(-6) to 1 x 10(-4) M in Britton-Robinson buffer at pH 7.0 with a correlation coefficient between 0.997 and 0.999 in supporting electrolyte and human serum samples using the DPV and SWV techniques. The repeatability and reproducibility of the methods for both media (supporting electrolyte and serum sample) were determined. Precision and accuracy of the developed methods were demonstrated by recovery studies. The standard addition method was used for the recovery studies. No electroactive interferences were found in biological fluids from endogenous substances or additives present in tablets. The methods developed were successfully applied to the determination of DNP in tablets and in spiked human serum.

  2. Trace analysis of Ponceau 4R in soft drinks using differential pulse stripping voltammetry at SWCNTs composite electrodes based on PEDOT:PSS derivatives.

    PubMed

    Wang, Zifei; Zhang, Hui; Wang, Zhipeng; Zhang, Jie; Duan, Xuemin; Xu, Jingkun; Wen, Yangping

    2015-08-01

    Ponceau 4R, an edible synthetic colorant used in drinks, syrups, and sweets, has been successfully detected using differential pulse voltammetry at a single-walled carbon nanotubes-modified composite electrode based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) and two derivatives thereof. The electrochemical parameters of three Ponceau 4R sensors, such as pH value, pre-concentration time, and scan rate, have been optimized, and their electrochemical performances have been compared. A poly(acrylate-modified 3,4-ethylenedioxythiophene-co-3,4-ethylenedioxythiophene):poly(styrene sulfonate)-single-walled carbon nanotubes-poly(vinyl alcohol)-modified electrode showed the best electrocatalytic activity, with the highest response current, lowest detection limit (1.8 nm), widest linear range (0.0055-110.6 μm), and best sensing stability. Additionally, the modified electrode has also been successfully employed for real sample analysis with soft drinks. Satisfactory results were obtained, demonstrating this to be an easy and effective approach for trace analysis of Ponceau 4R in food samples. PMID:25766817

  3. Self-doped anthranilic acid-pyrrole copolymer/gold electrodes for selective preconcentration and determination of Cu(I) by differential pulse anodic stripping voltammetry.

    PubMed

    Nateghi, M R; Fallahian, M H

    2007-05-01

    Electropolymerization of anthranilic acid/pyrrole (AA/PY) at solid substrate electrodes (platinum, gold, and glassy carbon) gave stable and water-insoluble films under a wide range of pH. Combining high conductivity of the polypyrrole (PPY) and pH independence of the electrochemical activity of the self-doped carboxylic acid-substituted polyaniline allows us to prepare an improved functionalized PPY-modified electrode to collect and measure Cu(I) species. The differential pulse stripping analysis of the copper ions using a polyanthranilic acid-co-polypyrrole (PAA/PPY)-modified electrode consisted of three steps: accumulation, electrochemical reduction to the elemental copper and stripping step. Factors affecting these steps, including electropolymerization conditions, accumulation and stripping medium, reduction potential, reduction time and accumulation time, were systematically investigated. A detection limit of 5.3 x 10(-9) M Cu(I) was achieved for a 7.0 min accumulation. For 12 determinations of Cu(I) at concentrations of 1.0 x 10(-8) M, an RSD of 3.5% was obtained. The log I(p) was found to vary linearly with log[Cu(I)] in the concentration range from 7.0 x 10(-9) to 1.0 x 10(-5) M.

  4. Differential pulse adsorptive stripping voltammetric determination of nanomolar levels of atorvastatin calcium in pharmaceutical and biological samples using a vertically aligned carbon nanotube/graphene oxide electrode.

    PubMed

    Silva, Tiago Almeida; Zanin, Hudson; Vicentini, Fernando Campanhã; Corat, Evaldo José; Fatibello-Filho, Orlando

    2014-06-01

    A novel vertically aligned carbon nanotube/graphene oxide (VACNT-GO) electrode is proposed, and its ability to determine atorvastatin calcium (ATOR) in pharmaceutical and biological samples by differential pulse adsorptive stripping voltammetry (DPAdSV) is evaluated. VACNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method and then treated with oxygen plasma to produce the VACNT-GO electrode. The oxygen plasma treatment exfoliates the carbon nanotube tips exposing graphene foils and inserting oxygen functional groups, these effects improved the VACNT wettability (super-hydrophobic) which is crucial for its electrochemical application. The electrochemical behaviour of ATOR on the VACNT-GO electrode was studied by cyclic voltammetry, which showed that it underwent an irreversible oxidation process at a potential of +1.08 V in pHcond 2.0 (0.2 mol L(-1) buffer phosphate solution). By applying DPAdSV under optimized experimental conditions the analytical curve was found to be linear in the ATOR concentration range of 90 to 3.81 × 10(3) nmol L(-1) with a limit of detection of 9.4 nmol L(-1). The proposed DPAdSV method was successfully applied in the determination of ATOR in pharmaceutical and biological samples, and the results were in close agreement with those obtained by a comparative spectrophotometric method at a confidence level of 95%.

  5. Binding of Hg2+ with phytochelatins: study by differential pulse voltammetry on rotating Au-disk electrode, electrospray ionization mass-spectrometry, and isothermal titration calorimetry.

    PubMed

    Chekmeneva, Elena; Díaz-Cruz, José Manuel; Arino, Cristina; Esteban, Miquel

    2009-09-15

    The binding of Hg2+ with synthetic phytochelatins ((gamma-Glu-Cys)n-Gly, PCn, n = 2, 3, 4) was investigated by a recently proposed electroanalytical method, using differential pulse voltammetry on the rotating Au-disk electrode, Electrospray ionization mass-spectrometry (ESI-MS) and isothermaltitration calorimetry (ITC). ESI-MS experiments provided the exact stoichiometries of the complexes formed at different PCn/Hg2+ ratios. Voltammetry provided more detailed information on the complexation processes through the use of multivariate curve resolution by alternating least squares of the data matrix obtained from titrations withfine increments of metal or ligand. The system Hg2+-GSH-PC2 was investigated by voltammetry in order to obtain an estimation of the Hg2+ behavior in the presence of two related ligands. The additional assessment of the stability of Hg2+-PCn complexes was achieved through ITC by using the therapeutic chelator sodium 2,3-dimercaptopropanesulfate (DMPS) over Hg2+-PCn systems. The stability of various Hg2+-PCn complexes and the ability of DMPS to replace PCn from these complexes were examined.

  6. Rapid determination of theophylline in serum by selective extraction using a heated molecularly imprinted polymer micro-column with differential pulsed elution.

    PubMed

    Mullett, W M; Lai, E P

    1999-12-01

    Molecular imprinting of theophylline in poly(methacrylic acid ethylene dimethacrylate) form binding sites with complementary size, shape and chemical functionalities to theophylline. This molecularly imprinted polymer (MIP) can be packed into a micro-column for selective solid phase extraction (SPE) of theophylline from 20 microl of sample solution. Its chemical inertness and thermal stability allow the use of various organic solvents and elevated column temperatures for effective binding of theophylline. Non-specific adsorption of interfering drugs on the MIP surface is eliminated by an intermediate wash with 20 microl of acetonitrile, prior to quantitative desorption of the bound theophylline by 20 microl of methanol for in-line UV spectrophotometric determination. In this differential pulsed elution (DPE) technique, both the column temperature and solvent flow rate can be optimized to enhance selectivity. Application of this micro-analytical method, molecularly imprinted solid phase extraction DPE (MISPE-DPE), is demonstrated for accurate determination of theophylline in human blood serum. The method is validated over a linear range from 2 microg/ml to at least 20 microg/ml.

  7. Determination of ultra-trace amounts of silver in water by differential pulse anodic stripping voltammetry using a new modified carbon paste electrode.

    PubMed

    El-Mai, Hafida; Espada-Bellido, Estrella; Stitou, Mostafa; García-Vargas, Manuel; Galindo-Riaño, Maria Dolores

    2016-05-01

    A highly sensitive and selective new procedure for the determination of silver in aqueous media was developed using a modified carbon paste electrode (MCPE) by differential pulse anodic stripping voltammetry (DPASV). The modified electrode was based on the incorporation of 2-hydroxybenzaldehyde benzoylhydrazone (2-HBBH) in the carbon paste electrode. Silver ions were preconcentrated on the modified electrode at open-circuit by complexation with the ligand and reduced to zero valent at a potential of 0V, and followed by the reoxidation of adsorbed ions onto the electrode by scanning the potential in a positive direction. The oxidation peak of Ag(I) was observed at 0.2V (versus Ag/AgCl). The analysis of Ag(I) was carried out in a cell containing the sample solution (20mL) buffered by 0.1molL(-1) K2HPO4/NaOH at pH 5.5 in aqueous solution and nitric acid (pH 1) in real water samples. The optimum conditions for the analysis of silver include a reduction potential of 0V and a pulse amplitude of 100mV, among others. The optimum carbon paste composition was found to be 14.1% (w/w) 2-HBBH, 56.2% (w/w) graphite powder and 29.7% (w/w) paraffin oil. Differential pulse anodic stripping voltammetric response was used as the analytical signal. Under the selected conditions, the voltammetric signal was proportional to the Ag(I) concentration in the range of 0.001-100μgL(-1) with favorable limits of detection and quantification of 1.1ngL(-1) and 3.7ngL(-1) after 3min of accumulation time, respectively. By increasing the accumulation time to 10min, detection and quantification limits can be further improved up to 0.1ngL(-1) and 0.34ngL(-1), respectively. In addition, the results showed a highly reproducible procedure showing a relative standard deviation of 1.5% for 12 replicate measurements. Many coexisting metal ions were investigated and very few interferences were found on the determination of Ag(I). The proposed method was validated using certified reference estuarine waters

  8. Adaptive population differentiation in phenology across a latitudinal gradient in European aspen (Populus tremula, L.): a comparison of neutral markers, candidate genes and phenotypic traits.

    PubMed

    Hall, David; Luquez, Virginia; Garcia, Victoria M; St Onge, Kate R; Jansson, Stefan; Ingvarsson, Pär K

    2007-12-01

    A correct timing of growth cessation and dormancy induction represents a critical ecological and evolutionary trade-off between survival and growth in most forest trees (Rehfeldt et al. 1999; Horvath et al. 2003; Howe et al. 2003). We have studied the deciduous tree European Aspen (Populus tremula) across a latitudinal gradient and compared genetic differentiation in phenology traits with molecular markers. Trees from 12 different areas covering 10 latitudinal degrees were cloned and planted in two common gardens. Several phenology traits showed strong genetic differentiation and clinal variation across the latitudinal gradient, with Q(ST) values generally exceeding 0.5. This is in stark contrast to genetic differentiation at several classes of genetic markers (18 neutral SSRs, 7 SSRs located close to phenology candidate genes and 50 SNPs from five phenology candidate genes) that all showed F(ST) values around 0.015. We thus find strong evidence for adaptive divergence in phenology traits across the latitudinal gradient. However, the strong population structure seen at the quantitative traits is not reflected in underlying candidate genes. This result fit theoretical expectations that suggest that genetic differentiation at candidate loci is better described by F(ST) at neutral loci rather than by Q(ST) at the quantitative traits themselves.

  9. Rapid and Adaptable Measurement of Protein Thermal Stability by Differential Scanning Fluorimetry: Updating a Common Biochemical Laboratory Experiment

    ERIC Educational Resources Information Center

    Johnson, R. Jeremy; Savas, Christopher J.; Kartje, Zachary; Hoops, Geoffrey C.

    2014-01-01

    Measurement of protein denaturation and protein folding is a common laboratory technique used in undergraduate biochemistry laboratories. Differential scanning fluorimetry (DSF) provides a rapid, sensitive, and general method for measuring protein thermal stability in an undergraduate biochemistry laboratory. In this method, the thermal…

  10. Development of an Airborne Triple-Pulse 2-Micron Integrated Path Differential Absorption Lidar (IPDA) for Simultaneous Airborne Column Measurements of Carbon Dioxide and Water Vapor in the Atmosphere

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong; Antill, Charles W.; Remus, Ruben

    2016-01-01

    This presentation will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar being developed at NASA Langley Research Center with support from NASA ESTO Instrument Incubator Program. The development of this active optical remote sensing IPDA instrument is targeted for measuring both atmospheric carbon dioxide and water vapor in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver and detector upgrades, laser packaging and lidar integration. Future plan for IPDA lidar system for ground integration, testing and flight validation will also be presented.

  11. Low-noise pulse conditioner

    DOEpatents

    Bird, David A.

    1983-01-01

    A low-noise pulse conditioner is provided for driving electronic digital processing circuitry directly from differentially induced input pulses. The circuit uses a unique differential-to-peak detector circuit to generate a dynamic reference signal proportional to the input peak voltage. The input pulses are compared with the reference signal in an input network which operates in full differential mode with only a passive input filter. This reduces the introduction of circuit-induced noise, or jitter, generated in ground referenced input elements normally used in pulse conditioning circuits, especially speed transducer processing circuits.

  12. Adaptive divergence despite strong genetic drift: genomic analysis of the evolutionary mechanisms causing genetic differentiation in the island fox (Urocyon littoralis).

    PubMed

    Funk, W Chris; Lovich, Robert E; Hohenlohe, Paul A; Hofman, Courtney A; Morrison, Scott A; Sillett, T Scott; Ghalambor, Cameron K; Maldonado, Jesus E; Rick, Torben C; Day, Mitch D; Polato, Nicholas R; Fitzpatrick, Sarah W; Coonan, Timothy J; Crooks, Kevin R; Dillon, Adam; Garcelon, David K; King, Julie L; Boser, Christina L; Gould, Nicholas; Andelt, William F

    2016-05-01

    The evolutionary mechanisms generating the tremendous biodiversity of islands have long fascinated evolutionary biologists. Genetic drift and divergent selection are predicted to be strong on islands and both could drive population divergence and speciation. Alternatively, strong genetic drift may preclude adaptation. We conducted a genomic analysis to test the roles of genetic drift and divergent selection in causing genetic differentiation among populations of the island fox (Urocyon littoralis). This species consists of six subspecies, each of which occupies a different California Channel Island. Analysis of 5293 SNP loci generated using Restriction-site Associated DNA (RAD) sequencing found support for genetic drift as the dominant evolutionary mechanism driving population divergence among island fox populations. In particular, populations had exceptionally low genetic variation, small Ne (range = 2.1-89.7; median = 19.4), and significant genetic signatures of bottlenecks. Moreover, islands with the lowest genetic variation (and, by inference, the strongest historical genetic drift) were most genetically differentiated from mainland grey foxes, and vice versa, indicating genetic drift drives genome-wide divergence. Nonetheless, outlier tests identified 3.6-6.6% of loci as high FST outliers, suggesting that despite strong genetic drift, divergent selection contributes to population divergence. Patterns of similarity among populations based on high FST outliers mirrored patterns based on morphology, providing additional evidence that outliers reflect adaptive divergence. Extremely low genetic variation and small Ne in some island fox populations, particularly on San Nicolas Island, suggest that they may be vulnerable to fixation of deleterious alleles, decreased fitness and reduced adaptive potential.

  13. High-order tracking differentiator based adaptive neural control of a flexible air-breathing hypersonic vehicle subject to actuators constraints.

    PubMed

    Bu, Xiangwei; Wu, Xiaoyan; Tian, Mingyan; Huang, Jiaqi; Zhang, Rui; Ma, Zhen

    2015-09-01

    In this paper, an adaptive neural controller is exploited for a constrained flexible air-breathing hypersonic vehicle (FAHV) based on high-order tracking differentiator (HTD). By utilizing functional decomposition methodology, the dynamic model is reasonably decomposed into the respective velocity subsystem and altitude subsystem. For the velocity subsystem, a dynamic inversion based neural controller is constructed. By introducing the HTD to adaptively estimate the newly defined states generated in the process of model transformation, a novel neural based altitude controller that is quite simpler than the ones derived from back-stepping is addressed based on the normal output-feedback form instead of the strict-feedback formulation. Based on minimal-learning parameter scheme, only two neural networks with two adaptive parameters are needed for neural approximation. Especially, a novel auxiliary system is explored to deal with the problem of control inputs constraints. Finally, simulation results are presented to test the effectiveness of the proposed control strategy in the presence of system uncertainties and actuators constraints.

  14. Single-Use Disposable Electrochemical Label-Free Immunosensor for Detection of Glycated Hemoglobin (HbA1c) Using Differential Pulse Voltammetry (DPV)

    PubMed Central

    Molazemhosseini, Alireza; Magagnin, Luca; Vena, Pasquale; Liu, Chung-Chiun

    2016-01-01

    A single-use disposable in vitro electrochemical immunosensor for the detection of HbA1c in undiluted human serum using differential pulse voltammetry (DPV) was developed. A three-electrode configuration electrochemical biosensor consisted of 10-nm-thin gold film working and counter electrodes and a thick-film printed Ag/AgCl reference electrode was fabricated on a polyethylene terephthalate (PET) substrate. Micro-fabrication techniques including sputtering vapor deposition and thick-film printing were used to fabricate the biosensor. This was a roll-to-roll cost-effective manufacturing process making the single-use disposable in vitro HbA1c biosensor a reality. Self-assembled monolayers of 3-Mercaptopropionic acid (MPA) were employed to covalently immobilize anti-HbA1c on the surface of gold electrodes. Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) confirmed the excellent coverage of MPA-SAM and the upward orientation of carboxylic groups. The hindering effect of HbA1c on the ferricyanide/ferrocyanide electron transfer reaction was exploited as the HbA1c detection mechanism. The biosensor showed a linear range of 7.5–20 µg/mL of HbA1c in 0.1 M PBS. Using undiluted human serum as the test medium, the biosensor presented an excellent linear behavior (R2 = 0.999) in the range of 0.1–0.25 mg/mL of HbA1c. The potential application of this biosensor for in vitro measurement of HbA1c for diabetic management was demonstrated. PMID:27376299

  15. Single-Use Disposable Electrochemical Label-Free Immunosensor for Detection of Glycated Hemoglobin (HbA1c) Using Differential Pulse Voltammetry (DPV).

    PubMed

    Molazemhosseini, Alireza; Magagnin, Luca; Vena, Pasquale; Liu, Chung-Chiun

    2016-01-01

    A single-use disposable in vitro electrochemical immunosensor for the detection of HbA1c in undiluted human serum using differential pulse voltammetry (DPV) was developed. A three-electrode configuration electrochemical biosensor consisted of 10-nm-thin gold film working and counter electrodes and a thick-film printed Ag/AgCl reference electrode was fabricated on a polyethylene terephthalate (PET) substrate. Micro-fabrication techniques including sputtering vapor deposition and thick-film printing were used to fabricate the biosensor. This was a roll-to-roll cost-effective manufacturing process making the single-use disposable in vitro HbA1c biosensor a reality. Self-assembled monolayers of 3-Mercaptopropionic acid (MPA) were employed to covalently immobilize anti-HbA1c on the surface of gold electrodes. Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) confirmed the excellent coverage of MPA-SAM and the upward orientation of carboxylic groups. The hindering effect of HbA1c on the ferricyanide/ferrocyanide electron transfer reaction was exploited as the HbA1c detection mechanism. The biosensor showed a linear range of 7.5-20 µg/mL of HbA1c in 0.1 M PBS. Using undiluted human serum as the test medium, the biosensor presented an excellent linear behavior (R² = 0.999) in the range of 0.1-0.25 mg/mL of HbA1c. The potential application of this biosensor for in vitro measurement of HbA1c for diabetic management was demonstrated. PMID:27376299

  16. Laser Raman detection of platelets for early and differential diagnosis of Alzheimer’s disease based on an adaptive Gaussian process classification algorithm

    NASA Astrophysics Data System (ADS)

    Luo, Yusheng; Du, Z. W.; Yang, Y. J.; Chen, P.; Tian, Q.; Shang, X. L.; Liu, Z. C.; Yao, X. Q.; Wang, J. Z.; Wang, X. H.; Cheng, Y.; Peng, J.; Shen, A. G.; Hu, J. M.

    2013-04-01

    Early and differential diagnosis of Alzheimer’s disease (AD) has puzzled many clinicians. In this work, laser Raman spectroscopy (LRS) was developed to diagnose AD from platelet samples from AD transgenic mice and non-transgenic controls of different ages. An adaptive Gaussian process (GP) classification algorithm was used to re-establish the classification models of early AD, advanced AD and the control group with just two features and the capacity for noise reduction. Compared with the previous multilayer perceptron network method, the GP showed much better classification performance with the same feature set. Besides, spectra of platelets isolated from AD and Parkinson’s disease (PD) mice were also discriminated. Spectral data from 4 month AD (n = 39) and 12 month AD (n = 104) platelets, as well as control data (n = 135), were collected. Prospective application of the algorithm to the data set resulted in a sensitivity of 80%, a specificity of about 100% and a Matthews correlation coefficient of 0.81. Samples from PD (n = 120) platelets were also collected for differentiation from 12 month AD. The results suggest that platelet LRS detection analysis with the GP appears to be an easier and more accurate method than current ones for early and differential diagnosis of AD.

  17. Use of ARMA predictors in the differential encoding of images

    NASA Astrophysics Data System (ADS)

    Sayood, Khalid; Schekall, Stanley M.

    1988-11-01

    Differential pulse code modulation (DPCM) has long been a popular method of data compression for speech. It has not been as popular for images, partly because of its poor edge performance. This is true even for adaptive DPCM (ADPCM). Gibson (1980) provides a clue to the reason for this shortcoming. This analysis is used to motivate the design of backward adaptive ARMA predictors for use in differential encoding of images. Simulations using these predictors validate the approach, as these systems show significant objective gains as well as noticeable subjective improvements in the edge performance. An added advantage to using this approach is the improvement in noisy-channel performance.

  18. Differential paired-pulse responses between the CA1 region and the dentate gyrus are related to altered CLC-2 immunoreactivity in the pilocarpine-induced rat epilepsy model.

    PubMed

    Kwak, Sung-Eun; Kim, Ji-Eun; Kim, Duk-Soo; Won, Moo Ho; Lee, Hong Jin; Choi, Soo-Young; Kwon, Oh-Shin; Kim, Jin-Sang; Kang, Tae-Cheon

    2006-10-18

    The epileptic hippocampus shows differential paired-pulse responses between the dentate gyrus and the CA1 region. However, little data are available to explain this phenomenon. In the present study, we identified the relationship between regional differences of paired-pulse response and voltage gated Cl(-) channel 2 (CLC-2)/vesicular GABA transport (VGAT) expression in a pilocarpine-induced rat model. During epileptogenic periods, paired-pulse inhibitions in the dentate gyrus and the CA1 region were markedly reduced. After recurrent seizure onset, paired-pulse inhibition in the dentate gyrus was markedly enhanced, while that in the CA1 region more reduced. Unlike VGAT, CLC-2 immunoreactivity was markedly reduced in the hippocampus during epileptogenic periods and was re-enhanced only in the dentate gyrus after recurrent seizure onset. Linear regression analysis showed an inverse proportional relationship between alterations in CLC-2 immunoreactivity and changes in normalized population spike amplitude ratio within the CA1 region and the dentate gyrus. Therefore, our findings suggest that the regionally specific alterations in CLC-2 immunoreactivity after SE may determine the properties of paired-pulse responses in the hippocampus of the pilocarpine-induced rat epilepsy model.

  19. Enhancement of Cell Ingrowth, Proliferation, and Early Differentiation in a Three-Dimensional Silicon Carbide Scaffold Using Low-Intensity Pulsed Ultrasound

    PubMed Central

    Lin, Liangjun

    2015-01-01

    Concerns over the use of autografts or allografts have necessitated the development of biomaterials for bone regeneration. Various studies have been performed to optimize the cultivation of osteogenic cells using osteoconductive porous scaffolds. The aim of this study was to evaluate the osteogenic efficiency of bone cell ingrowth, proliferation, and early differentiation in a silicon carbide (SiC) porous ceramic scaffold promoted with low-intensity pulsed ultrasound. MC3T3-E1 mouse preosteoblasts were seeded onto scaffolds and cultured for 4 and 7 days with daily of 20-min ultrasound treatment. The cells were evaluated for cell attachment, morphology, viability, ingrowth depth, volumetric proliferation, and early differentiation. After 4 and 7 days of culture and ultrasound exposure, the cell density was higher in the ultrasound-treated group compared with the sham-treated group on SiC scaffolds. The cell ingrowth depths inside the SiC scaffolds were 149.2±27.3 μm at 1 day, 310.1±12.6 μm for the ultrasound-treated group and 248.0±19.7 μm for the sham control at 4 days, and 359.6±18.5 μm for the ultrasound-treated group and 280.0±17.7 μm for the sham control at 7 days. They were significantly increased, that is, 25% (p=0.0029) and 28% (p=0.0008) increase, respectively, with ultrasound radiation force as compared with those in sham control at 4 and 7 days postseeding. The dsDNA contents were 583.5±19.1 ng/scaffold at 1 day, 2749.9±99.9 ng/scaffold for the ultrasound-treated group and 2514.9±114.7 ng/scaffold for the sham control at 4 days, and 3582.3±325.3 ng/scaffold for the ultrasound-treated group and 2825.7±134.3 ng/scaffold for the sham control at 7 days. There was a significant difference in the dsDNA content between the ultrasound- and sham-treated groups at 4 and 7 days. The ultrasound-treated group with the SiC construct showed a 9% (p=0.00029) and 27% (p=0.00017) increase in the average dsDNA content at 4 and 7 days over

  20. An adaptive high-dimensional stochastic model representation technique for the solution of stochastic partial differential equations

    SciTech Connect

    Ma Xiang; Zabaras, Nicholas

    2010-05-20

    A computational methodology is developed to address the solution of high-dimensional stochastic problems. It utilizes high-dimensional model representation (HDMR) technique in the stochastic space to represent the model output as a finite hierarchical correlated function expansion in terms of the stochastic inputs starting from lower-order to higher-order component functions. HDMR is efficient at capturing the high-dimensional input-output relationship such that the behavior for many physical systems can be modeled to good accuracy only by the first few lower-order terms. An adaptive version of HDMR is also developed to automatically detect the important dimensions and construct higher-order terms using only the important dimensions. The newly developed adaptive sparse grid collocation (ASGC) method is incorporated into HDMR to solve the resulting sub-problems. By integrating HDMR and ASGC, it is computationally possible to construct a low-dimensional stochastic reduced-order model of the high-dimensional stochastic problem and easily perform various statistic analysis on the output. Several numerical examples involving elementary mathematical functions and fluid mechanics problems are considered to illustrate the proposed method. The cases examined show that the method provides accurate results for stochastic dimensionality as high as 500 even with large-input variability. The efficiency of the proposed method is examined by comparing with Monte Carlo (MC) simulation.

  1. H2S exposure elicits differential expression of candidate genes in fish adapted to sulfidic and non-sulfidic environments.

    PubMed

    Tobler, Michael; Henpita, Chathurika; Bassett, Brandon; Kelley, Joanna L; Shaw, Jennifer H

    2014-09-01

    Disentangling the effects of plasticity, genetic variation, and their interactions on organismal responses to environmental stressors is a key objective in ecological physiology. We quantified the expression of five candidate genes in response to hydrogen sulfide (H2S) exposure in fish (Poecilia mexicana, Poeciliidae) from a naturally sulfide-rich environment as well as an ancestral, non-sulfidic population to test for constitutive and environmentally dependent population differences in gene expression patterns. Common garden raised individuals that had never encountered environmental H2S during their lifetime were subjected to short or long term H2S exposure treatments or respective non-sulfidic controls. The expression of genes involved in responses to H2S toxicity (cytochrome c oxidase, vascular endothelial growth factor, and cytochrome P450-2J6), H2S detoxification (sulfide:quinone oxidoreductase), and endogenous H2S production (cystathionine γ lyase) was determined in both gill and liver tissues by real time PCR. The results indicated complex changes in expression patterns that--depending on the gene--not only differed between organs and populations, but also on the type of H2S exposure. Populations differences, both constitutive and H2S exposure dependent (i.e., plastic), in gene expression were particularly evident for sulfide:quinone oxidoreductase, vascular endothelial growth factor, and to a lesser degree for cytochrome P450-2J6. Our study uncovered putatively adaptive modifications in gene regulation that parallel previously documented adaptive changes in phenotypic traits.

  2. Differential photosynthetic and morphological adaptations to low light affect depth distribution of two submersed macrophytes in lakes

    PubMed Central

    Chen, Jianfeng; Cao, Te; Zhang, Xiaolin; Xi, Yilong; Ni, Leyi; Jeppesen, Erik

    2016-01-01

    To evaluate the relative importance of photosynthetic versus morphological adaptations of submersed macrophytes to low light intensity in lakes, rapid light curves (RLCs), morphological parameters, relative growth rate (RGR), clonal reproduction and abundance of two submersed macrophytes (Potamogeton maackianus and Vallisneria natans) were examined under 2.8%, 7.1%, 17.1% and 39.5% ambient light in a field and outdoor experimental study. The plants increased their initial slope of RLCs (α) and decreased their minimum saturating irradiance (Ek) and maximum relative electron transport rate (ETRm) of RLCs under low light stress, but V. natans was more sensitive in RLCs than P. maackianus. Accordingly, the RGR, plant height and abundance of P. maackianus were higher in the high light regimes (shallow water) but lower in the low light regimes than those of V. natans. At the 2.8% ambient light, V. natans produced ramets and thus fulfilled its population expansion, in contrast to P. maackianus. The results revealed that P. maackianus as a canopy-former mainly elongated its shoot length towards the water surface to compensate for the low light conditions, however, it became limited in severe low light stress conditions. V. natans as a rosette adapted to low light stress mainly through photosynthetic adjustments and superior to severely low light than shoot elongation. PMID:27694880

  3. Intrinsic and Tumor Microenvironment-Induced Metabolism Adaptations of T Cells and Impact on Their Differentiation and Function.

    PubMed

    Kouidhi, Soumaya; Noman, Muhammad Zaeem; Kieda, Claudine; Elgaaied, Amel Benammar; Chouaib, Salem

    2016-01-01

    It is well recognized that the immune system and metabolism are highly integrated. In this context, multilevel interactions between metabolic system and T lymphocyte signaling and fate exist. This review will discuss different potential cell metabolism pathways involved in shaping T lymphocyte function and differentiation. We will also provide a general framework for understanding how tumor microenvironmental metabolism, associated with hypoxic stress, interferes with T-cell priming and expansion. How T-cell metabolism drives T-cell-mediated immunity and how the manipulation of metabolic programing for therapeutic purposes will be also discussed. PMID:27066006

  4. Differential metabolic and endocrine adaptations in llamas, sheep, and goats fed high- and low-protein grass-based diets.

    PubMed

    Kiani, A; Alstrup, L; Nielsen, M O

    2015-10-01

    This study aimed to elucidate whether distinct endocrine and metabolic adaptations provide llamas superior ability to adapt to low protein content grass-based diets as compared with the true ruminants. Eighteen adult, nonpregnant females (6 llamas, 6 goats, and 6 sheep) were fed either green grass hay with (HP) or grass seed straw (LP) in a cross-over design experiment over 2 periods of 21 d. Blood samples were taken on day 21 in each period at -30, 60, 150, and 240 min after feeding the morning meal and analyzed for plasma contents of glucose, triglyceride, nonesterified fatty acids, β-hydroxy butyrate (BOHB), urea, creatinine, insulin, and leptin. Results showed that llamas vs sheep and goats had higher plasma concentrations of glucose (7.1 vs 3.5 and 3.6 ± 0.18 mmol/L), creatinine (209 vs 110 and 103 ± 10 μmol/L), and urea (6.7 vs 5.6 and 4.9 ± 0.5 mmol/L) but lower leptin (0.33 vs 1.49 and 1.05 ± 0.1 ng/mL) and BOHB (0.05 vs 0.26 and 0.12 ± 0.02 mmol/L), respectively. BOHB in llamas was extremely low for a ruminating animal. Llamas showed that hyperglycemia coexisted with hyperinsulinemia (in general on the HP diet; postprandially on the LP diet). Llamas were clearly hypercreatinemic compared with the true ruminants, which became further exacerbated on the LP diet, where they also sustained plasma urea at markedly higher concentrations. However, llamas had markedly lower leptin concentrations than the true ruminants. In conclusion, llamas appear to have an intrinsic insulin resistant phenotype. Augmentation of creatinine and sustenance of elevated plasma urea concentrations in llamas when fed the LP diet must reflect distinct metabolic adaptations of intermediary protein and/or nitrogen metabolism, not observed in the true ruminants. These features can contribute to explain lower metabolic rates in llamas compared with the true ruminants, which must improve the chances of survival on low protein content diets.

  5. H2S exposure elicits differential expression of candidate genes in fish adapted to sulfidic and non-sulfidic environments.

    PubMed

    Tobler, Michael; Henpita, Chathurika; Bassett, Brandon; Kelley, Joanna L; Shaw, Jennifer H

    2014-09-01

    Disentangling the effects of plasticity, genetic variation, and their interactions on organismal responses to environmental stressors is a key objective in ecological physiology. We quantified the expression of five candidate genes in response to hydrogen sulfide (H2S) exposure in fish (Poecilia mexicana, Poeciliidae) from a naturally sulfide-rich environment as well as an ancestral, non-sulfidic population to test for constitutive and environmentally dependent population differences in gene expression patterns. Common garden raised individuals that had never encountered environmental H2S during their lifetime were subjected to short or long term H2S exposure treatments or respective non-sulfidic controls. The expression of genes involved in responses to H2S toxicity (cytochrome c oxidase, vascular endothelial growth factor, and cytochrome P450-2J6), H2S detoxification (sulfide:quinone oxidoreductase), and endogenous H2S production (cystathionine γ lyase) was determined in both gill and liver tissues by real time PCR. The results indicated complex changes in expression patterns that--depending on the gene--not only differed between organs and populations, but also on the type of H2S exposure. Populations differences, both constitutive and H2S exposure dependent (i.e., plastic), in gene expression were particularly evident for sulfide:quinone oxidoreductase, vascular endothelial growth factor, and to a lesser degree for cytochrome P450-2J6. Our study uncovered putatively adaptive modifications in gene regulation that parallel previously documented adaptive changes in phenotypic traits. PMID:24813672

  6. Morphometric and genetic differentiation of two sibling gossamer-wing damselflies, Euphaea formosa and E. yayeyamana, and adaptive trait divergence in subtropical East Asian islands.

    PubMed

    Lee, Yat-Hung; Lin, Chung-Ping

    2012-01-01

    Insular species frequently demonstrate different tendencies to become smaller or larger than their continental relatives. Two sibling gossamer-wing damselflies, Euphaea formosa (Odonata: Euphaeidae) from Taiwan and E. yayeyamana from the Yaeyama Islands of Japan, have no clear structural differentiation, and can only be recognized by their geographical distribution, sizes, and subtle differences in wing shape and coloration. This study combined morphometric and genetic techniques to investigate the adaptive significance of trait divergence and species status in these two Euphaea damselflies. Phylogenetic analyses of the mitochondrial cox2 sequences demonstrated that the two damselflies are monophyletic lineages and constitute valid phylogenetic species. The landmark-based geometric morphometrics indicated that the two damselflies are different morphological species characterized by distinctive wing shapes. The larger E. formosa exhibited broader hind wings, whereas E. yayeyamana had narrower and elongated forewings. The body size and wing shape variations among populations of the two species do not follow the expected pattern of neutral evolution, suggesting that the evolutionary divergence of these two traits is likely to be subjected to natural or sexual selection. The decreased body size, elongated forewings, and narrower hind wings of E. yayeyamana may represent insular adaptation to limited resources and reduced territorial competition on smaller islands. PMID:22963544

  7. Morphometric and Genetic Differentiation of Two Sibling Gossamer-Wing Damselflies, Euphaea formosa and E. yayeyamana, and Adaptive Trait Divergence in Subtropical East Asian Islands

    PubMed Central

    Lee, Yat-Hung; Lin, Chung-Ping

    2012-01-01

    Insular species frequently demonstrate different tendencies to become smaller or larger than their continental relatives. Two sibling gossamer—wing damselflies, Euphaea formosa (Odonata: Euphaeidae) from Taiwan and E. yayeyamana from the Yaeyama Islands of Japan, have no clear structural differentiation, and can only be recognized by their geographical distribution, sizes, and subtle differences in wing shape and coloration. This study combined morphometric and genetic techniques to investigate the adaptive significance of trait divergence and species status in these two Euphaea damselflies. Phylogenetic analyses of the mitochondrial cox2 sequences demonstrated that the two damselflies are monophyletic lineages and constitute valid phylogenetic species. The landmark—based geometric morphometrics indicated that the two damselflies are different morphological species characterized by distinctive wing shapes. The larger E. formosa exhibited broader hind wings, whereas E. yayeyamana had narrower and elongated forewings. The body size and wing shape variations among populations of the two species do not follow the expected pattern of neutral evolution, suggesting that the evolutionary divergence of these two traits is likely to be subjected to natural or sexual selection. The decreased body size, elongated forewings, and narrower hind wings of E. yayeyamana may represent insular adaptation to limited resources and reduced territorial competition on smaller islands. PMID:22963544

  8. [The effects of pulsed electromagnetic fields on the induction of rat bone marrow mesenchymal stem cells to differentiate into cardiomyocytes-like cells in vitro].

    PubMed

    Feng, Xian; He, Xueling; Li, Kai; Wu, Wenchao; Liu, Xiaojing; Li, Liang

    2011-08-01

    The aim of this study is to investigate the effects of pulsed electromagnetic fields (PEMFs) on the induction of rat bone marrow mesenchymal stem cells (rBMSCs) to differentiate into cardiomyocytes-like cells in vitro. rBMSCs were randomly divided into PEMFs groups, 5-Azacytidine (5-Aza) groups and control groups. PEMFs groups were exposed to 50 Hz, 1 mT PEMFs for 30 min every day, lasting for 10 d, 15 d and 20 d, respectively. 5-Aza groups were induced by 10 micromol/L 5-Aza for 1 day, then the medium was changed to complete medium without 5-Aza. And control groups were only cultured with complete medium, rBMSCs growth status and morphological features were observed by inverted phase microscope every day. The mRNA expressions of cardiac troponin T (TNNT2) and alpha-actinin (ACTN2) were determined by Real-Time PCR. The results showed that rBMSCs were spindle, polygon or fusiform in control groups. The cells gradually got longer and grew close together after being stimulated by PEMFs and 5-Aza, and with the extension of induction time, the tendency became obvious. At 20th day after PEMFs or 5-Aza treatment, rBMSCs gathered like a long chain, got much longer obviously at the high magnification, and some of them even fused with their neighbors. Compared with control groups, the levels of TNNT2 mRNA expression in 5-Aza groups were 19.40 fold (P < 0.01), 21.02 fold (P < 0.01) and 2.38 fold at 10 d, 15 d, 20 d and the levels of ACTN2 mRNA expression in 5-Aza groups were 6.64 fold (P < 0.01), 6.67 fold (P < 0.01) and 0.76 fold at 10 d, 15 d, 20 d. However, the levels of TNNT2 mRNA expression in PEMFs groups were 15.78 fold (P < 0.01), 6.73 fold (P < 0.05) and 2.73 fold (P < 0.01) of control groups at 10 d, 15 d, 20 d and the levels of ACTN2 mRNA expression in PEMFs groups were 4.93 fold (P < 0.01), 1.89 fold and 0.64 fold, respectively. Compared with 5-Aza groups, the levels of TNNT2 mRNA expression in PEMFs groups were 0.81 fold, 0.32 fold (P < 0.01) and 1.15 fold at 10

  9. Differential adaptation to multi-stressed conditions of wine fermentation revealed by variations in yeast regulatory networks

    PubMed Central

    2013-01-01

    Background Variation of gene expression can lead to phenotypic variation and have therefore been assumed to contribute the diversity of wine yeast (Saccharomyces cerevisiae) properties. However, the molecular bases of this variation of gene expression are unknown. We addressed these questions by carrying out an integrated genetical-genomic study in fermentation conditions. We report here quantitative trait loci (QTL) mapping based on expression profiling in a segregating population generated by a cross between a derivative of the popular wine strain EC1118 and the laboratory strain S288c. Results Most of the fermentation traits studied appeared to be under multi-allelic control. We mapped five phenotypic QTLs and 1465 expression QTLs. Several expression QTLs overlapped in hotspots. Among the linkages unraveled here, several were associated with metabolic processes essential for wine fermentation such as glucose sensing or nitrogen and vitamin metabolism. Variations affecting the regulation of drug detoxification and export (TPO1, PDR12 or QDR2) were linked to variation in four genes encoding transcription factors (PDR8, WAR1, YRR1 and HAP1). We demonstrated that the allelic variation of WAR1 and TPO1 affected sorbic and octanoic acid resistance, respectively. Moreover, analysis of the transcription factors phylogeny suggests they evolved with a specific adaptation of the strains to wine fermentation conditions. Unexpectedly, we found that the variation of fermentation rates was associated with a partial disomy of chromosome 16. This disomy resulted from the well known 8–16 translocation. Conclusions This large data set made it possible to decipher the effects of genetic variation on gene expression during fermentation and certain wine fermentation properties. Our findings shed a new light on the adaptation mechanisms required by yeast to cope with the multiple stresses generated by wine fermentation. In this context, the detoxification and export systems appear

  10. Genome scan of the mitten crab Eriocheir sensu stricto in East Asia: population differentiation, hybridization and adaptive speciation.

    PubMed

    Xu, Jiawu; Chu, Ka Hou

    2012-07-01

    We examine the genetic structure and evolutionary history of the mitten crab Eriocheir sensu stricto in East Asia by employing a genome scan - amplified fragment length polymorphism. Population analysis reveals three divergent clades in Eriocheir s. s., which dominate the East China Sea-Yellow Sea, the Sea of Japan (plus Okinawa) and the South China Sea, respectively, mostly in agreement with our previous mtDNA analysis. With the tropical South China Sea inferred as the origin, the East China Sea-Yellow Sea and the Sea of Japan clades in the north diverged successively from the ancestral clade during the mid-Pleistocene. The divergence of the three clades likely resulted from isolation of the three marginal seas caused by sea level change in the Pleistocene. Two sympatric zones, one of the East China Sea-Yellow Sea and the South China Sea clades in southeast China and the other of the East China Sea-Yellow Sea and the Sea of Japan clades in Vladivostok, are demonstrated to be hybrid zones, with hybridization occurring currently in the former but historically in the latter. Adaptive speciation is observed in the divergence process of the three clades, possibly because of selection from accumulated temperature. Our study indicates that the genetic structure and evolutionary history of Eriocheir s. s. have been primarily affected by Pleistocene glacial cycles, secondarily by divergent selection and drainage isolation, but only minimally by human activities.

  11. Differential influence of nutrient-starved Mycobacterium tuberculosis on adaptive immunity results in progressive tuberculosis disease and pathology.

    PubMed

    Dietrich, Jes; Roy, Sugata; Rosenkrands, Ida; Lindenstrøm, Thomas; Filskov, Jonathan; Rasmussen, Erik Michael; Cassidy, Joseph; Andersen, Peter

    2015-12-01

    When infected with Mycobacterium tuberculosis, most individuals will remain clinically healthy but latently infected. Latent infection has been proposed to partially involve M. tuberculosis in a nonreplicating stage, which therefore represents an M. tuberculosis phenotype that the immune system most likely will encounter during latency. It is therefore relevant to examine how this particular nonreplicating form of M. tuberculosis interacts with the host immune system. To study this, we first induced a state of nonreplication through prolonged nutrient starvation of M. tuberculosis in vitro. This resulted in nonreplicating persistence even after prolonged culture in phosphate-buffered saline. Infection with either exponentially growing M. tuberculosis or nutrient-starved M. tuberculosis resulted in similar lung CFU levels in the first phase of the infection. However, between week 3 and 6 postinfection, there was a very pronounced increase in bacterial levels and associated lung pathology in nutrient-starved-M. tuberculosis-infected mice. This was associated with a shift from CD4 T cells that coexpressed gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) or IFN-γ, TNF-α, and interleukin-2 to T cells that only expressed IFN-γ. Thus, nonreplicating M. tuberculosis induced through nutrient starvation promotes a bacterial form that is genetically identical to exponentially growing M. tuberculosis yet characterized by a differential impact on the immune system that may be involved in undermining host antimycobacterial immunity and facilitate increased pathology and transmission. PMID:26416911

  12. Mosaic microecological differential stress causes adaptive microsatellite divergence in wild barley, Hordeum spontaneum, at Neve Yaar, Israel.

    PubMed

    Huang, Qingyang; Beharav, Alex; Li, Youchun; Kirzhner, Valery; Nevo, Eviatar

    2002-12-01

    Genetic diversity at 38 microsatellite (short sequence repeats (SSRs)) loci was studied in a sample of 54 plants representing a natural population of wild barley, Hordeum spontaneum, at the Neve Yaar microsite in Israel. Wild barley at the microsite was organized in a mosaic pattern over an area of 3180 m2 in the open Tabor oak forest, which was subdivided into four microniches: (i) sun-rock (11 genotypes), (ii) sun-soil (18 genotypes), (iii) shade-soil (11 genotypes), and (iv) shade-rock (14 genotypes). Fifty-four genotypes were tested for ecological-genetic microniche correlates. Analysis of 36 loci showed that allele distributions at SSR loci were nonrandom but structured by ecological stresses (climatic and edaphic). Sixteen (45.7%) of 35 polymorphic loci varied significantly (p < 0.05) in allele frequencies among the microniches. Significant genetic divergence and diversity were found among the four subpopulations. The soil and shade subpopulations showed higher genetic diversities at SSR loci than the rock and sun subpopulations, and the lowest genetic diversity was observed in the sun-rock subpopulation, in contrast with the previous allozyme and RAPD studies. On average, of 36 loci, 88.75% of the total genetic diversity exists within the four microniches, while 11.25% exists between the microniches. In a permutation test, G(ST) was lower for 4999 out of 5000 randomized data sets (p < 0.001) when compared with real data (0.1125). The highest genetic distance was between shade-soil and sun-rock (D = 0.222). Our results suggest that diversifying natural selection may act upon some regulatory regions, resulting in adaptive SSR divergence. Fixation of some loci (GMS61, GMS1, and EBMAC824) at a specific microniche seems to suggest directional selection. The pattern of other SSR loci suggests the operation of balancing selection. SSRs may be either direct targets of selection or markers of selected haplotypes (selective sweep). PMID:12502268

  13. Uncertainty based modeling of rainfall-runoff: Combined differential evolution adaptive Metropolis (DREAM) and K-means clustering

    NASA Astrophysics Data System (ADS)

    Zahmatkesh, Zahra; Karamouz, Mohammad; Nazif, Sara

    2015-09-01

    Simulation of rainfall-runoff process in urban areas is of great importance considering the consequences and damages of extreme runoff events and floods. The first issue in flood hazard analysis is rainfall simulation. Large scale climate signals have been proved to be effective in rainfall simulation and prediction. In this study, an integrated scheme is developed for rainfall-runoff modeling considering different sources of uncertainty. This scheme includes three main steps of rainfall forecasting, rainfall-runoff simulation and future runoff prediction. In the first step, data driven models are developed and used to forecast rainfall using large scale climate signals as rainfall predictors. Due to high effect of different sources of uncertainty on the output of hydrologic models, in the second step uncertainty associated with input data, model parameters and model structure is incorporated in rainfall-runoff modeling and simulation. Three rainfall-runoff simulation models are developed for consideration of model conceptual (structural) uncertainty in real time runoff forecasting. To analyze the uncertainty of the model structure, streamflows generated by alternative rainfall-runoff models are combined, through developing a weighting method based on K-means clustering. Model parameters and input uncertainty are investigated using an adaptive Markov Chain Monte Carlo method. Finally, calibrated rainfall-runoff models are driven using the forecasted rainfall to predict future runoff for the watershed. The proposed scheme is employed in the case study of the Bronx River watershed, New York City. Results of uncertainty analysis of rainfall-runoff modeling reveal that simultaneous estimation of model parameters and input uncertainty significantly changes the probability distribution of the model parameters. It is also observed that by combining the outputs of the hydrological models using the proposed clustering scheme, the accuracy of runoff simulation in the

  14. Cooperative pulses

    NASA Astrophysics Data System (ADS)

    Braun, Michael; Glaser, Steffen J.

    2010-11-01

    We introduce the concept of cooperative (COOP) pulses which are designed to compensate each other's imperfections. In multi-scan experiments, COOP pulses can cancel undesired signal contributions, complementing and generalizing phase cycles. COOP pulses can be efficiently optimized using an extended version of the optimal-control-based gradient ascent pulse engineering (GRAPE) algorithm. The advantage of the COOP approach is experimentally demonstrated for broadband and band-selective pulses.

  15. Adhesion- and Degranulation-Promoting Adapter Protein Promotes CD8 T Cell Differentiation and Resident Memory Formation and Function during an Acute Infection.

    PubMed

    Fiege, Jessica K; Beura, Lalit K; Burbach, Brandon J; Shimizu, Yoji

    2016-09-15

    During acute infections, naive Ag-specific CD8 T cells are activated and differentiate into effector T cells, most of which undergo contraction after pathogen clearance. A small population of CD8 T cells persists as memory to protect against future infections. We investigated the role of adhesion- and degranulation-promoting adapter protein (ADAP) in promoting CD8 T cell responses to a systemic infection. Naive Ag-specific CD8 T cells lacking ADAP exhibited a modest expansion defect early after Listeria monocytogenes or vesicular stomatitis virus infection but comparable cytolytic function at the peak of response. However, reduced numbers of ADAP-deficient CD8 T cells were present in the spleen after the peak of the response. ADAP deficiency resulted in a greater frequency of CD127(+) CD8 memory precursors in secondary lymphoid organs during the contraction phase. Reduced numbers of ADAP-deficient killer cell lectin-like receptor G1(-) CD8 resident memory T (TRM) cell precursors were present in a variety of nonlymphoid tissues at the peak of the immune response, and consequently the total numbers of ADAP-deficient TRM cells were reduced at memory time points. TRM cells that did form in the absence of ADAP were defective in effector molecule expression. ADAP-deficient TRM cells exhibited impaired effector function after Ag rechallenge, correlating with defects in their ability to form T cell-APC conjugates. However, ADAP-deficient TRM cells responded to TGF-β signals and recruited circulating memory CD8 T cells. Thus, ADAP regulates CD8 T cell differentiation events following acute pathogen challenge that are critical for the formation and selected functions of TRM cells in nonlymphoid tissues. PMID:27521337

  16. PULSE SORTER

    DOEpatents

    Wade, E.J.

    1958-07-29

    An apparatus is described for counting and recording the number of electrical pulses occurring in each of a timed sequence of groups of pulses. The particular feature of the invention resides in a novel timing circuit of the univibrator type which provides very accurately timed pulses for opening each of a series of coincidence channels in sequence. The univibrator is shown incorporated in a pulse analyzing system wherein a series of pulse counting channels are periodically opened in order, one at a time, for a predetermtned open time interval, so that only one channel will be open at the time of occurrence of any of the electrical pulses to be sorted.

  17. An effective hybrid self-adapting differential evolution algorithm for the joint replenishment and location-inventory problem in a three-level supply chain.

    PubMed

    Wang, Lin; Qu, Hui; Chen, Tao; Yan, Fang-Ping

    2013-01-01

    The integration with different decisions in the supply chain is a trend, since it can avoid the suboptimal decisions. In this paper, we provide an effective intelligent algorithm for a modified joint replenishment and location-inventory problem (JR-LIP). The problem of the JR-LIP is to determine the reasonable number and location of distribution centers (DCs), the assignment policy of customers, and the replenishment policy of DCs such that the overall cost is minimized. However, due to the JR-LIP's difficult mathematical properties, simple and effective solutions for this NP-hard problem have eluded researchers. To find an effective approach for the JR-LIP, a hybrid self-adapting differential evolution algorithm (HSDE) is designed. To verify the effectiveness of the HSDE, two intelligent algorithms that have been proven to be effective algorithms for the similar problems named genetic algorithm (GA) and hybrid DE (HDE) are chosen to compare with it. Comparative results of benchmark functions and randomly generated JR-LIPs show that HSDE outperforms GA and HDE. Moreover, a sensitive analysis of cost parameters reveals the useful managerial insight. All comparative results show that HSDE is more stable and robust in handling this complex problem especially for the large-scale problem. PMID:24453822

  18. Pulse Oximetry

    MedlinePlus

    ... www.thoracic.org amount of gases (oxygen and carbon dioxide) that are in your blood. To get an ... Also, a pulse oximeter does not measure your carbon dioxide level. How accurate is the pulse oximeter? The ...

  19. Arterial pulse wave pressure transducer

    NASA Technical Reports Server (NTRS)

    Kim, C.; Gorelick, D.; Chen, W. (Inventor)

    1974-01-01

    An arterial pulse wave pressure transducer is introduced. The transducer is comprised of a fluid filled cavity having a flexible membrane disposed over the cavity and adapted to be placed on the skin over an artery. An arterial pulse wave creates pressure pulses in the fluid which are transduced, by a pressure sensitive transistor in direct contact with the fluid, into an electric signal. The electrical signal is representative of the pulse waves and can be recorded so as to monitor changes in the elasticity of the arterial walls.

  20. PULSED ION SOURCE

    DOEpatents

    Ford, F.C.; Ruff, J.W.; Zizzo, S.G.; Cook, B.

    1958-11-11

    An ion source is described adapted for pulsed operation and producing copious quantities of ions with a particular ion egress geometry. The particular source construction comprises a conical member having a conducting surface formed of a metal with a gas occladed therein and narrow non-conducting portions hereon dividing the conducting surface. A high voltage pulse is applied across the conducting surface or producing a discharge across the surface. After the gas ions have been produced by the discharge, the ions are drawn from the source in a diverging conical beam by a specially constructed accelerating electrode.

  1. PULSE GENERATOR

    DOEpatents

    Roeschke, C.W.

    1957-09-24

    An improvement in pulse generators is described by which there are produced pulses of a duration from about 1 to 10 microseconds with a truly flat top and extremely rapid rise and fall. The pulses are produced by triggering from a separate input or by modifying the current to operate as a free-running pulse generator. In its broad aspect, the disclosed pulse generator comprises a first tube with an anode capacitor and grid circuit which controls the firing; a second tube series connected in the cathode circuit of the first tube such that discharge of the first tube places a voltage across it as the leading edge of the desired pulse; and an integrator circuit from the plate across the grid of the second tube to control the discharge time of the second tube, determining the pulse length.

  2. Differential two-signal picosecond-pulse coherent anti-Stokes Raman scattering imaging microscopy by using a dual-mode optical parametric oscillator.

    PubMed

    Yoo, Yong Shim; Lee, Dong-Hoon; Cho, Hyuck

    2007-11-15

    We propose and demonstrate a novel differential two-signal technique of coherent anti-Stokes Raman scattering (CARS) imaging microscopy using a picosecond (ps) optical parametric oscillator (OPO). By adjusting a Lyot filter inside the cavity, we operated the OPO oscillating in two stable modes separated by a few nanometers. The CARS images generated by the two modes are separated by a spectrograph behind the microscope setup, and their differential image is directly obtained by balanced lock-in detection. The feasibility of the technique is experimentally verified by imaging micrometer-sized polystyrene beads immersed in water. PMID:18026271

  3. Integrating Evolutionary and Functional Tests of Adaptive Hypotheses: A Case Study of Altitudinal Differentiation in Hemoglobin Function in an Andean Sparrow, Zonotrichia capensis

    PubMed Central

    Cheviron, Zachary A.; Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Eddy, Douglas K.; Jones, Jennifer; Carling, Matthew D.; Witt, Christopher C.; Moriyama, Hideaki; Weber, Roy E.; Fago, Angela; Storz, Jay F.

    2014-01-01

    In air-breathing vertebrates, the physiologically optimal blood-O2 affinity is jointly determined by the prevailing partial pressure of atmospheric O2, the efficacy of pulmonary O2 transfer, and internal metabolic demands. Consequently, genetic variation in the oxygenation properties of hemoglobin (Hb) may be subject to spatially varying selection in species with broad elevational distributions. Here we report the results of a combined functional and evolutionary analysis of Hb polymorphism in the rufous-collared sparrow (Zonotrichia capensis), a species that is continuously distributed across a steep elevational gradient on the Pacific slope of the Peruvian Andes. We integrated a population genomic analysis that included all postnatally expressed Hb genes with functional studies of naturally occurring Hb variants, as well as recombinant Hb (rHb) mutants that were engineered through site-directed mutagenesis. We identified three clinally varying amino acid polymorphisms: Two in the αA-globin gene, which encodes the α-chain subunits of the major HbA isoform, and one in the αD-globin gene, which encodes the α-chain subunits of the minor HbD isoform. We then constructed and experimentally tested single- and double-mutant rHbs representing each of the alternative αA-globin genotypes that predominate at different elevations. Although the locus-specific patterns of altitudinal differentiation suggested a history of spatially varying selection acting on Hb polymorphism, the experimental tests demonstrated that the observed amino acid mutations have no discernible effect on respiratory properties of the HbA or HbD isoforms. These results highlight the importance of experimentally validating the hypothesized effects of genetic changes in protein function to avoid the pitfalls of adaptive storytelling. PMID:25135942

  4. Molecular cloning and expression studies of the adapter molecule myeloid differentiation factor 88 (MyD88) in turbot (Scophthalmus maximus).

    PubMed

    Lin, Jing-Yun; Hu, Guo-Bin; Yu, Chang-Hong; Li, Song; Liu, Qiu-Ming; Zhang, Shi-Cui

    2015-10-01

    Myeloid differentiation factor 88 (MyD88) is an adapter protein involved in the interleukin-1 receptor (IL-1R) and Toll-like receptor (TLR)-mediated activation of nuclear factor-kappaB (NF-κB). In this study, a full length cDNA of MyD88 was cloned from turbot, Scophthalmus maximus. It is 1619 bp in length and contains an 858-bp open reading frame that encodes a peptide of 285 amino acid residues. The putative turbot (Sm)MyD88 protein possesses a N-terminal death domain and a C-terminal Toll/IL-1 receptor (TIR) domain known to be important for the functions of MyD88 in mammals. Phylogenetic analysis grouped SmMyD88 with other fish MyD88s. SmMyD88 mRNA was ubiquitously expressed in all examined tissues of healthy turbots, with higher levels observed in immune-relevant organs. To explore the role of SmMyD88, its gene expression profile in response to stimulation of lipopolysaccharide (LPS), CpG oligodeoxynucleotide (CpG-ODN) or turbot reddish body iridovirus (TRBIV) was studied in the head kidney, spleen, gills and muscle over a 7-day time course. The results showed an up-regulation of SmMyD88 transcript levels by the three immunostimulants in all four examined tissues, with the induction by CpG-ODN strongest and initiated earliest and inducibility in the muscle very weak. Additionally, TRBIV challenge resulted in a quite high level of SmMyD88 expression in the spleen, whereas the two synthetic immunostimulants induced the higher levels in the head kidney. These data provide insights into the roles of SmMyD88 in the TLR/IL-1R signaling pathway of the innate immune system in turbot. PMID:26025195

  5. Performance of the variable weighting function pulse processor

    SciTech Connect

    Kuwata, M.; Saito, N.; Maeda, H.; Minami, T.; Watanabe, T.; Husimi, K.; Ohkawa, S.

    1998-06-01

    The authors have developed a new time variant pulse processor which is able to adapt the weighting function according to the detector noise characteristics in order to get the best performance from a semiconductor x-ray detecting system. The circuit construction is almost the same as the previously presented trapezoidal filter that was composed of a rectangular prefilter and a gated integrator. The rectangular waveform was formed by adding a differentiated signal and an integration of the differentiated signal with the same ratio. In the new process it is possible to vary the weighting function continuously by changing the mixing ratio of the differentiated waveform and the integrated one. Noise analysis of the filter has been carried out by using SPICE. This technique is very useful for determining the noise response of a filter simply by the circuit design.

  6. Low-noise pulse conditioner

    DOEpatents

    Bird, D.A.

    1981-06-16

    A low-noise pulse conditioner is provided for driving electronic digital processing circuitry directly from differentially induced input pulses. The circuit uses a unique differential-to-peak detector circuit to generate a dynamic reference signal proportional to the input peak voltage. The input pulses are compared with the reference signal in an input network which operates in full differential mode with only a passive input filter. This reduces the introduction of circuit-induced noise, or jitter, generated in ground referenced input elements normally used in pulse conditioning circuits, especially speed transducer processing circuits. This circuit may be used for conditioning the sensor signal from the Fidler coil in a gas centrifuge for separation of isotopic gaseous mixtures.

  7. High-speed pulse-shape generator, pulse multiplexer

    DOEpatents

    Burkhart, Scott C.

    2002-01-01

    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  8. Short-term differential adaptation to anaerobic stress via genomic mutations by Escherichia coli strains K-12 and B lacking alcohol dehydrogenase

    PubMed Central

    Kim, Hyun Ju; Jeong, Haeyoung; Hwang, Seungwoo; Lee, Moo-Seung; Lee, Yong-Jik; Lee, Dong-Woo; Lee, Sang Jun

    2014-01-01

    Microbial adaptations often occur via genomic mutations under adverse environmental conditions. This study used Escherichia coli ΔadhE cells as a model system to investigate adaptation to anaerobic conditions, which we then compared with the adaptive mechanisms of two closely related E. coli strains, K-12 and B. In contrast to K-12 ΔadhE cells, the E. coli B ΔadhE cells exhibited significantly delayed adaptive growth under anaerobic conditions. Adaptation by the K-12 and B strains mainly employed anaerobic lactate fermentation to restore cellular growth. Several mutations were identified in the pta or pflB genes of adapted K-12 cells, but mostly in the pta gene of the B strains. However, the types of mutation in the adapted K-12 and B strains were similar. Cellular viability was affected directly by severe redox imbalance in B ΔadhE cells, which also impaired their ability to adapt to anaerobic conditions. This study demonstrates that closely related microorganisms may undergo different adaptations under the same set of adverse conditions, which might be associated with the specific metabolic characteristics of each strain. This study provides new insights into short-term microbial adaptation to stressful conditions, which may reflect dynamic microbial population changes in nature. PMID:25250024

  9. Short-term differential adaptation to anaerobic stress via genomic mutations by Escherichia coli strains K-12 and B lacking alcohol dehydrogenase.

    PubMed

    Kim, Hyun Ju; Jeong, Haeyoung; Hwang, Seungwoo; Lee, Moo-Seung; Lee, Yong-Jik; Lee, Dong-Woo; Lee, Sang Jun

    2014-01-01

    Microbial adaptations often occur via genomic mutations under adverse environmental conditions. This study used Escherichia coli ΔadhE cells as a model system to investigate adaptation to anaerobic conditions, which we then compared with the adaptive mechanisms of two closely related E. coli strains, K-12 and B. In contrast to K-12 ΔadhE cells, the E. coli B ΔadhE cells exhibited significantly delayed adaptive growth under anaerobic conditions. Adaptation by the K-12 and B strains mainly employed anaerobic lactate fermentation to restore cellular growth. Several mutations were identified in the pta or pflB genes of adapted K-12 cells, but mostly in the pta gene of the B strains. However, the types of mutation in the adapted K-12 and B strains were similar. Cellular viability was affected directly by severe redox imbalance in B ΔadhE cells, which also impaired their ability to adapt to anaerobic conditions. This study demonstrates that closely related microorganisms may undergo different adaptations under the same set of adverse conditions, which might be associated with the specific metabolic characteristics of each strain. This study provides new insights into short-term microbial adaptation to stressful conditions, which may reflect dynamic microbial population changes in nature.

  10. Pulse stretcher

    DOEpatents

    Horton, J.A.

    1994-05-03

    Apparatus for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse is disclosed. The apparatus uses a White cell having a plurality of optical delay paths of successively increasing number of passes between the field mirror and the objective mirrors. A pulse from a laser travels through a multi-leg reflective path between a beam splitter and a totally reflective mirror to the laser output. The laser pulse is also simultaneously injected through the beam splitter to the input mirrors of the optical delay paths. The pulses from the output mirrors of the optical delay paths go simultaneously to the laser output and to the input mirrors of the longer optical delay paths. The beam splitter is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output. 6 figures.

  11. Differential pulse voltammetric determination of nimesulide in pharmaceutical formulation and human serum at glassy carbon electrode modified by cysteic acid/CNTs base on electrochemical oxidation of L-cysteine.

    PubMed

    Wang, Chengyin; Shao, Xiaoqiu; Liu, Qingxiu; Qu, Qishu; Yang, Gongjun; Hu, Xiaoya

    2006-09-18

    Carbon nanotubes (CNTs) and cysteic acid based on electrochemical oxidation of L-cysteine (CySH) to form a novel composite thin film material at a glassy carbon electrode (GCE) for electroanalytical determination of nimesulide. The determination of nimesulide at the composite modified electrode with strong accumulation of nimesulide was studied by differential pulse voltammetry (DPV). The peak current obtained at +1.251 V (versus SCE) from DPV was linearly dependent on the nimesulide concentration in the range of 1.0 x 10(-7) -1.0 x 10(-5) M in 0.05 M H(2)SO(4) solution with a correlation coefficient of 0.997. The detection limit (S/N = 3) was found to be 5.0 x 10(-8) M. The low-cost modified electrode showed good sensitivity, selectivity, stability and had been applied to the determination of nimesulide in pharmaceutical formulation and human serum samples with satisfactory results.

  12. Adaptive control for accelerators

    DOEpatents

    Eaton, Lawrie E.; Jachim, Stephen P.; Natter, Eckard F.

    1991-01-01

    An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.

  13. Pulse Voltammetry

    NASA Astrophysics Data System (ADS)

    Stojek, Zbigniew

    The idea of imposing potential pulses and measuring the currents at the end of each pulse was proposed by Barker in a little-known journal as early as in 1958 [1]. However, the first reliable trouble-free and affordable polarographs offering voltammetric pulse techniques appeared on the market only in the 1970s. This delay was due to some limitations on the electronic side. In the 1990s, again substantial progress in electrochemical pulse instrumentation took place. This was related to the introduction of microprocessors, computers, and advanced software.

  14. Self-adaptive, narrowband tuning of a pulsed optical parametric oscillator and a continuous-wave diode laser via phase-conjugate photorefractive cavity reflectors: verification by high-resolution spectroscopy

    NASA Astrophysics Data System (ADS)

    He, Y.; Orr, B. J.

    2009-08-01

    A dynamic self-adaptive Bragg grating formed in a photorefractive crystal is shown to be a convenient way to attain single-longitudinal-mode (SLM) operation and narrowband tuning both in a pulsed, injection-seeded optical parametric oscillator (OPO) and in a continuous-wave (cw) extended-cavity diode laser. The pulsed OPO cavity comprises a Rh:BaTiO3 photorefractive (PR) crystal, a periodically poled KTiOPO4 nonlinear-optical crystal, and a dielectrically-coated end mirror. A continuous-wave seed beam at 820-850 nm from a tunable SLM diode laser traverses firstly the Rh:BaTiO3 crystal and then is retro-reflected by the end mirror; this creates a wavelength-selective Bragg grating reflector in the PR crystal, thereby completing the OPO cavity. The cavity stays automatically resonant with the seed radiation, with no need to actively control its length or to make any other mechanical adjustment. One form of injection seeder comprises a novel extended-cavity diode laser (ECDL) design incorporating a self-pumped photorefractive phase-conjugate reflector and a compact, high-finesse tunable intracavity ring filter. This combination facilitates robust tunable single-frequency operation with narrow optical bandwidth. The performance characteristics of the OPO and the ECDL are evaluated by recording high-resolution atomic and molecular spectra. Notably, fluorescence-detected sub-Doppler two-photon excitation at 822 nm, of the 8 S ←6 S transition in atomic Cs, provides a crucial linewidth test.

  15. PULSE AMPLIFIER

    DOEpatents

    Johnstone, C.W.

    1958-06-17

    The improvement of pulse amplifiers used with scintillation detectors is described. The pulse amplifier circuit has the advantage of reducing the harmful effects of overloading cause by large signal inputs. In general the pulse amplifier circuit comprises two amplifier tubes with the input pulses applied to one amplifier grid and coupled to the second amplifier tube through a common cathode load. The output of the second amplifier is coupled from the plate circuit to a cathode follower tube grid and a diode tube in connected from grid to cathode of the cathode follower tube. Degenerative feedback is provided in the second amplifier by coupling a signal from the cathode follower cathode to the second amplifier grid. The circuit proqides moderate gain stability, and overload protection for subsequent pulse circuits.

  16. Adaptation to ER Stress Is Mediated by Differential Stabilities of Pro-Survival and Pro-Apoptotic mRNAs and Proteins

    PubMed Central

    Rutkowski, D. Thomas; Arnold, Stacey M; Miller, Corey N; Wu, Jun; Li, Jack; Gunnison, Kathryn M; Mori, Kazutoshi; Sadighi Akha, Amir A.; Raden, David; Kaufman, Randal J

    2006-01-01

    The accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates a signaling cascade known as the unfolded protein response (UPR). Although activation of the UPR is well described, there is little sense of how the response, which initiates both apoptotic and adaptive pathways, can selectively allow for adaptation. Here we describe the reconstitution of an adaptive ER stress response in a cell culture system. Monitoring the activation and maintenance of representative UPR gene expression pathways that facilitate either adaptation or apoptosis, we demonstrate that mild ER stress activates all UPR sensors. However, survival is favored during mild stress as a consequence of the intrinsic instabilities of mRNAs and proteins that promote apoptosis compared to those that facilitate protein folding and adaptation. As a consequence, the expression of apoptotic proteins is short-lived as cells adapt to stress. We provide evidence that the selective persistence of ER chaperone expression is also applicable to at least one instance of genetic ER stress. This work provides new insight into how a stress response pathway can be structured to allow cells to avert death as they adapt. It underscores the contribution of posttranscriptional and posttranslational mechanisms in influencing this outcome. PMID:17090218

  17. Adaptive Phase Delay Generator

    NASA Technical Reports Server (NTRS)

    Greer, Lawrence

    2013-01-01

    There are several experimental setups involving rotating machinery that require some form of synchronization. The adaptive phase delay generator (APDG) the Bencic-1000 is a flexible instrument that allows the user to generate pulses synchronized to the rising edge of a tachometer signal from any piece of rotating machinery. These synchronized pulses can vary by the delay angle, pulse width, number of pulses per period, number of skipped pulses, and total number of pulses. Due to the design of the pulse generator, any and all of these parameters can be changed independently, yielding an unparalleled level of versatility. There are two user interfaces to the APDG. The first is a LabVIEW program that has the advantage of displaying all of the pulse parameters and input signal data within one neatly organized window on the PC monitor. Furthermore, the LabVIEW interface plots the rpm of the two input signal channels in real time. The second user interface is a handheld portable device that goes anywhere a computer is not accessible. It consists of a liquid-crystal display and keypad, which enable the user to control the unit by scrolling through a host of command menus and parameter listings. The APDG combines all of the desired synchronization control into one unit. The experimenter can adjust the delay, pulse width, pulse count, number of skipped pulses, and produce a specified number of pulses per revolution. Each of these parameters can be changed independently, providing an unparalleled level of versatility when synchronizing hardware to a host of rotating machinery. The APDG allows experimenters to set up quickly and generate a host of synchronizing configurations using a simple user interface, which hopefully leads to faster results.

  18. A newly adapted pulsed-field gel electrophoresis technique allows to detect distinct types of DNA damage at low frequencies in human dermal fibroblasts upon exposure to non-toxic H2O2 concentrations.

    PubMed

    Brenneisen, P; Wenk, J; Wlaschek, M; Blaudschun, R; Scharffetter-Kochanek, K

    1999-11-01

    Reactive oxygen species (ROS) comprise several oxygen containing compounds, among them hydrogen peroxide (H2O2), which are generated by internal and external sources and play pleiotropic roles in physiological and pathological states. Skin cells as well as cells from other tissues have developed antioxidant defense mechanisms to protect themselves from high concentrations of ROS. Although biological and pathological roles of ROS have previously been elucidated, so far only limited knowledge exists regarding ROS-mediated generation of DNA breaks and base lesions occurring at low frequency in intact skin cells. This study was therefore designed to probe a newly adapted pulsed-field gel electrophoresis technique for the adequate measurement of high molecular weight DNA fragments as well as to investigate the protective role of the antioxidant enzyme catalase against H2O2-mediated damage in human dermal fibroblasts. We stably transfected and overexpressed the full-length catalase cDNA in the human dermal fibroblast cell line 1306 in culture and found that these cells are significantly more protected from cytotoxicity, overall DNA strand breaks, and 8-oxodeoxyguanine base lesions resulting from H2O2-triggered oxidative stress compared to vector-transfected 1306 cells or secondary dermal fibroblasts. This work has outlined the importance of catalase in the protection from H2O2-mediated cytotoxicity and DNA damage which--if unbalanced--even when occurring at low frequency are known to lead to genomic instability, a hallmark in carcinogenesis and premature aging.

  19. Comparison of Two Multilocus Variable-Number Tandem-Repeat Methods and Pulsed-Field Gel Electrophoresis for Differentiating Highly Clonal Methicillin-Resistant Staphylococcus aureus Isolates▿

    PubMed Central

    Holmes, A.; Edwards, G. F.; Girvan, E. K.; Hannant, W.; Danial, J.; Fitzgerald, J. R.; Templeton, K. E.

    2010-01-01

    In the United Kingdom, EMRSA-15 and EMRSA-16 account for the majority (∼90%) of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections. Currently, the standard typing technique, pulsed-field gel electrophoresis (PFGE), is laborious and insufficient for discriminating between closely related subtypes of EMRSA-15 and -16. The objective of the present study was to compare the usefulness of multilocus variable-number tandem-repeat fingerprinting (MLVF) and multilocus variable-number tandem-repeat analysis (MLVA) with PFGE for subtyping these highly clonal MRSA lineages. A panel of 85 MRSA isolates (41 EMRSA-15, 20 EMRSA-16, and 24 MRSA isolates with diverse PFGE patterns) was investigated. In addition, a further 29 EMRSA-15s with identical PFGE patterns from two geographically linked but epidemiologically distinct outbreaks and several sporadic cases were analyzed. PFGE, MLVF, and MLVA resolved 66 (Simpson's index of diversity [SID] = 0.984), 51 (SID = 0.95), and 42 (SID = 0.881) types, respectively, among the 85 MRSA isolates. MLVF was more discriminatory than MLVA for EMRSA-15 and -16 strains, but both methods had comparable discriminatory powers for distinguishing isolates in the group containing diverse PFGE types. MLVF was comparable to PFGE for resolving the EMRSA-15s but had a lower discriminatory power for the EMRSA-16s. MLVF and MLVA resolved the 29 isolates with identical PFGE patterns into seven and six subtypes, respectively. Importantly, both assays indicated that the two geographically related outbreaks were caused by distinct subtypes of EMRSA-15. Taken together, the data suggest that both methods are suitable for identifying and tracking specific subtypes of otherwise-indistinguishable MRSA. However, due to its greater discriminatory power, MLVF would be the most suitable alternative to PFGE for hospital outbreak investigations. PMID:20702668

  20. Pulse Data.

    ERIC Educational Resources Information Center

    Hands On!, 1998

    1998-01-01

    Presents an activity using computer software to investigate the role of the heart and blood, how the blood system responds to exercise, and how pulse rate is a good measure of physical condition. (ASK)

  1. Pulse stretcher

    DOEpatents

    Horton, James A.

    1994-01-01

    Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

  2. Intestinal adaptation after extensive small bowel resection: differential changes in growth and insulin-like growth factor system messenger ribonucleic acids in jejunum and ileum.

    PubMed

    Ziegler, T R; Mantell, M P; Chow, J C; Rombeau, J L; Smith, R J

    1998-07-01

    The distal small bowel exhibits greater adaptive growth than proximal segments after partial small intestine resection. To explore this process, we evaluated adaptive cellularity, intestinal insulin-like growth factor (IGF) system messenger RNA (mRNA) transcripts, and effects of recombinant IGF-I treatment in jejunum and ileum of adult rats. Gastrostomy-fed animals underwent 80% jejuno-ileal resection or intestinal transection and reanastomosis without resection, followed by infusion of human recombinant IGF-I (2.4 mg/kgXday) or vehicle. After 7 days, resected rats demonstrated modest adaptive growth in jejunum and marked cell proliferation in ileum. Resection increased IGF-I mRNA in both jejunum (183%) and ileum (249%) and up-regulated IGFBP-4 mRNA levels in both tissues. IGFBP-3 mRNA fell significantly in ileum after resection. IGF-I infusion modestly increased ileal cellularity after resection, but had no effect in jejunum. IGF-I markedly increased IGFBP-3 mRNA levels in jejunum after both transection and resection. These data confirm that bowel resection induces greater adaptive growth in ileum than jejunum. IGF-I administration modestly increases ileal, but not jejunal, growth after resection. Increased levels of intestinal IGF-I and IGFBP-4 mRNA suggest roles for IGF-I and IGFBP-4 in mediating small bowel adaptation. Higher levels of jejunal IGFBP-3 mRNA may be related to limited jejunal vs. ileal growth after extensive jejuno-ileal resection.

  3. Identification of adaptive mutations in the influenza A virus non-structural 1 gene that increase cytoplasmic localization and differentially regulate host gene expression.

    PubMed

    Forbes, Nicole; Selman, Mohammed; Pelchat, Martin; Jia, Jian Jun; Stintzi, Alain; Brown, Earl G

    2013-01-01

    The NS1 protein of influenza A virus (IAV) is a multifunctional virulence factor. We have previously characterized gain-of-function mutations in the NS1 protein arising from the experimental adaptation of the human isolate A/Hong Kong/1/1968(H3N2) (HK) to the mouse. The majority of these mouse adapted NS1 mutations were demonstrated to increase virulence, viral fitness, and interferon antagonism, but differ in binding to the post-transcriptional processing factor cleavage and polyadenylation specificity factor 30 (CPSF30). Because nuclear trafficking is a major genetic determinant of influenza virus host adaptation, we assessed subcellular localization and host gene expression of NS1 adaptive mutations. Recombinant HK viruses with adaptive mutations in the NS1 gene were assessed for NS1 protein subcellular localization in mouse and human cells using confocal microscopy and cellular fractionation. In human cells the HK wild-type (HK-wt) virus NS1 protein partitioned equivalently between the cytoplasm and nucleus but was defective in cytoplasmic localization in mouse cells. Several adaptive mutations increased the proportion of NS1 in the cytoplasm of mouse cells with the greatest effects for mutations M106I and D125G. The host gene expression profile of the adaptive mutants was determined by microarray analysis of infected mouse cells to show either high or low extents of host-gene regulation (HGR or LGR) phenotypes. While host genes were predominantly down regulated for the HGR group of mutants (D2N, V23A, F103L, M106I+L98S, L98S, M106V, and M106V+M124I), the LGR phenotype mutants (D125G, M106I, V180A, V226I, and R227K) were characterized by a predominant up regulation of host genes. CPSF30 binding affinity of NS1 mutants did not predict effects on host gene expression. To our knowledge this is the first report of roles of adaptive NS1 mutations that impact intracellular localization and regulation of host gene expression.

  4. Stably operating pulse combustor and method

    DOEpatents

    Zinn, B.T.; Reiner, D.

    1990-05-29

    A pulse combustor apparatus is described which is adapted to burn either a liquid fuel or a pulverized solid fuel within a preselected volume of the combustion chamber. The combustion process is substantially restricted to an optimum combustion zone in order to attain effective pulse combustion operation. 4 figs.

  5. Stably operating pulse combustor and method

    DOEpatents

    Zinn, Ben T.; Reiner, David

    1990-01-01

    A pulse combustor apparatus adapted to burn either a liquid fuel or a pulverized solid fuel within a preselected volume of the combustion chamber. The combustion process is substantially restricted to an optimum combustion zone in order to attain effective pulse combustion operation.

  6. Pressure pulse detection apparatus

    SciTech Connect

    Claycomb, J.R.

    1981-04-14

    A pressure pulse detection apparatus is disclosed which is adapted to receive small signals from downhole measuring while drilling apparatus which signals are propogated as pressure pulses traveling upstream in a column of drilling mud, which signals are obscured by mud pump pressure and velocity variations traveling downstream and which are significantly larger. The preferred embodiment incorporates a transient pressure transducer and an ultrasonic fluid velocity detector, the two forming output signals which are conditioned, amplified and offset against one another. They cancel (When properly calibrated) so that pressure and velocity variations from the mud pump upstream are nulled to zero. They reinforce so that pressure and velocity variations from the downhole signal generator are enhanced, thereby forming an output signal of downhole variations of interest.

  7. Differential Roles of Hydrogen Peroxide in Adaptive and Inflammatory Gene Expression Induced by Exposure of Human Airway Epithelial Cells to Zn2+

    EPA Science Inventory

    Oxidant stress is believed to play an important role in particulate matter (PM)–mediated toxicity in the respiratory tract. Zinc (Zn2+) is a ubiquitous component of PM that has been shown to induce adverse responses such as inflammatory and adaptive gene expression in airway epit...

  8. Displacement damage in bit error ratio performance of on-off keying, pulse position modulation, differential phase shift keying, and homodyne binary phase-shift keying-based optical intersatellite communication system.

    PubMed

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Dong, Chen; Li, Xuan

    2016-04-10

    Displacement damage (DD) effect induced bit error ratio (BER) performance degradations in on-off keying (OOK), pulse position modulation (PPM), differential phase-shift keying (DPSK), and homodyne binary phase shift keying (BPSK) based systems were simulated and discussed under 1 MeV neutron irradiation to a total fluence of 1×1012  n/cm2 in this paper. Degradation of main optoelectronic devices included in communication systems were analyzed on the basis of existing experimental data. The system BER degradation was subsequently simulated and the variations of BER with different neutron irradiation location were also achieved. The result shows that DD on an Er-doped fiber amplifier (EDFA) is the dominant cause of system degradation, and a BPSK-based system performs better than the other three systems against DD. In order to improve radiation hardness of communication systems against DD, protection and enhancement of EDFA are required, and the use of a homodyne BPSK modulation scheme is a considered choice.

  9. Regional vertical total electron content (VTEC) modeling together with satellite and receiver differential code biases (DCBs) using semi-parametric multivariate adaptive regression B-splines (SP-BMARS)

    NASA Astrophysics Data System (ADS)

    Durmaz, Murat; Karslioglu, Mahmut Onur

    2015-04-01

    There are various global and regional methods that have been proposed for the modeling of ionospheric vertical total electron content (VTEC). Global distribution of VTEC is usually modeled by spherical harmonic expansions, while tensor products of compactly supported univariate B-splines can be used for regional modeling. In these empirical parametric models, the coefficients of the basis functions as well as differential code biases (DCBs) of satellites and receivers can be treated as unknown parameters which can be estimated from geometry-free linear combinations of global positioning system observables. In this work we propose a new semi-parametric multivariate adaptive regression B-splines (SP-BMARS) method for the regional modeling of VTEC together with satellite and receiver DCBs, where the parametric part of the model is related to the DCBs as fixed parameters and the non-parametric part adaptively models the spatio-temporal distribution of VTEC. The latter is based on multivariate adaptive regression B-splines which is a non-parametric modeling technique making use of compactly supported B-spline basis functions that are generated from the observations automatically. This algorithm takes advantage of an adaptive scale-by-scale model building strategy that searches for best-fitting B-splines to the data at each scale. The VTEC maps generated from the proposed method are compared numerically and visually with the global ionosphere maps (GIMs) which are provided by the Center for Orbit Determination in Europe (CODE). The VTEC values from SP-BMARS and CODE GIMs are also compared with VTEC values obtained through calibration using local ionospheric model. The estimated satellite and receiver DCBs from the SP-BMARS model are compared with the CODE distributed DCBs. The results show that the SP-BMARS algorithm can be used to estimate satellite and receiver DCBs while adaptively and flexibly modeling the daily regional VTEC.

  10. Use of biomimetic microtissue spheroids and specific growth factor supplementation to improve tenocyte differentiation and adaptation to a collagen-based scaffold in vitro.

    PubMed

    Theiss, Felix; Mirsaidi, Ali; Mhanna, Rami; Kümmerle, Jan; Glanz, Stephan; Bahrenberg, Gregor; Tiaden, André N; Richards, Peter J

    2015-11-01

    Tenocytes represent a valuable source of cells for the purposes of tendon tissue engineering and regenerative medicine and as such, should possess a high degree of tenogenic differentiation prior to their use in vivo in order to achieve maximal efficacy. In the current report, we identify an efficient means by which to maintain differentiated tenocytes in vitro by employing the hanging drop technique in combination with defined growth media supplements. Equine tenocytes retained a more differentiated state when cultured as scaffold-free microtissue spheroids in low serum-containing medium supplemented with L-ascorbic acid 2-phosphate, insulin and transforming growth factor (TGF)-β1. This was made evident by significant increases in the expression levels of pro-tenogenic markers collagen type I (COL1A2), collagen type III (COL3A1), scleraxis (SCX) and tenomodulin (TNMD), as well as by enhanced levels of collagen type I and tenomodulin protein. Furthermore, tenocytes cultured under these conditions demonstrated a typical spindle-like morphology and when embedded in collagen gels, became highly aligned with respect to the orientation of the collagen structure following their migration out from the microtissue spheroids. Our findings therefore provide evidence to support the use of a biomimetic microtissue approach to culturing tenocytes and that in combination with the defined growth media described, can improve their differentiation status and functional repopulation of collagen matrix.

  11. Use of biomimetic microtissue spheroids and specific growth factor supplementation to improve tenocyte differentiation and adaptation to a collagen-based scaffold in vitro.

    PubMed

    Theiss, Felix; Mirsaidi, Ali; Mhanna, Rami; Kümmerle, Jan; Glanz, Stephan; Bahrenberg, Gregor; Tiaden, André N; Richards, Peter J

    2015-11-01

    Tenocytes represent a valuable source of cells for the purposes of tendon tissue engineering and regenerative medicine and as such, should possess a high degree of tenogenic differentiation prior to their use in vivo in order to achieve maximal efficacy. In the current report, we identify an efficient means by which to maintain differentiated tenocytes in vitro by employing the hanging drop technique in combination with defined growth media supplements. Equine tenocytes retained a more differentiated state when cultured as scaffold-free microtissue spheroids in low serum-containing medium supplemented with L-ascorbic acid 2-phosphate, insulin and transforming growth factor (TGF)-β1. This was made evident by significant increases in the expression levels of pro-tenogenic markers collagen type I (COL1A2), collagen type III (COL3A1), scleraxis (SCX) and tenomodulin (TNMD), as well as by enhanced levels of collagen type I and tenomodulin protein. Furthermore, tenocytes cultured under these conditions demonstrated a typical spindle-like morphology and when embedded in collagen gels, became highly aligned with respect to the orientation of the collagen structure following their migration out from the microtissue spheroids. Our findings therefore provide evidence to support the use of a biomimetic microtissue approach to culturing tenocytes and that in combination with the defined growth media described, can improve their differentiation status and functional repopulation of collagen matrix. PMID:26283157

  12. Differential enrichment of TTF-I and Tip5 in the T-like promoter structures of the rDNA contribute to the epigenetic response of Cyprinus carpio during environmental adaptation.

    PubMed

    Nardocci, Gino; Simonet, Nicolas G; Navarro, Cristina; Längst, Gernot; Alvarez, Marco

    2016-08-01

    To ensure homeostasis, ectothermic organisms adapt to environmental variations through molecular mechanisms. We previously reported that during the seasonal acclimatization of the common carp Cyprinus carpio, molecular and cellular functions are reprogrammed, resulting in distinctive traits. Importantly, the carp undergoes a drastic rearrangement of nucleolar components during adaptation. This ultrastructural feature reflects a fine modulation of rRNA gene transcription. Specifically, we identified the involvement of the transcription termination factor I (TTF-I) and Tip-5 (member of nucleolar remodeling complex, NoRC) in the control of rRNA transcription. Our results suggest that differential Tip5 enrichment is essential for silencing carp ribosomal genes and that the T0 element is key for regulating the ribosomal gene during the acclimatization process. Interestingly, the expression and content of Tip5 were significantly higher in winter than in summer. Since carp ribosomal gene expression is lower in the winter than in summer, and considering that expression concomitantly occurs with nucleolar ultrastructural changes of the acclimatization process, these results indicate that Tip5 importantly contributes to silencing the ribosomal genes. In conclusion, the current study provides novel evidence on the contributions of TTF-I and NoRC in the environmental reprogramming of ribosomal genes during the seasonal adaptation process in carp. PMID:27458840

  13. Flow towards diagonalization for many-body-localization models: adaptation of the Toda matrix differential flow to random quantum spin chains

    NASA Astrophysics Data System (ADS)

    Monthus, Cécile

    2016-07-01

    The iterative methods to diagonalize matrices and many-body Hamiltonians can be reformulated as flows of Hamiltonians towards diagonalization driven by unitary transformations that preserve the spectrum. After a comparative overview of the various types of discrete flows (Jacobi, QR-algorithm) and differential flows (Toda, Wegner, White) that have been introduced in the past, we focus on the random XXZ chain with random fields in order to determine the best closed flow within a given subspace of running Hamiltonians. For the special case of the free-fermion random XX chain with random fields, the flow coincides with the Toda differential flow for tridiagonal matrices which is related to the classical integrable Toda chain and which can be seen as the continuous analog of the discrete QR-algorithm. For the random XXZ chain with random fields that displays a many-body-localization transition, the present differential flow should be an interesting alternative to compare with the discrete flow that has been proposed recently to study the many-body-localization properties in a model of interacting fermions (Rademaker and Ortuno 2016 Phys. Rev. Lett. 116, 010404).

  14. A Study of New Pulse Auscultation System

    PubMed Central

    Chen, Ying-Yun; Chang, Rong-Seng

    2015-01-01

    This study presents a new type of pulse auscultation system, which uses a condenser microphone to measure pulse sound waves on the wrist, captures the microphone signal for filtering, amplifies the useful signal and outputs it to an oscilloscope in analog form for waveform display and storage and delivers it to a computer to perform a Fast Fourier Transform (FFT) and convert the pulse sound waveform into a heartbeat frequency. Furthermore, it also uses an audio signal amplifier to deliver the pulse sound by speaker. The study observed the principles of Traditional Chinese Medicine’s pulsing techniques, where pulse signals at places called “cun”, “guan” and “chi” of the left hand were measured during lifting (100 g), searching (125 g) and pressing (150 g) actions. Because the system collects the vibration sound caused by the pulse, the sensor itself is not affected by the applied pressure, unlike current pulse piezoelectric sensing instruments, therefore, under any kind of pulsing pressure, it displays pulse changes and waveforms with the same accuracy. We provide an acquired pulse and waveform signal suitable for Chinese Medicine practitioners’ objective pulse diagnosis, thus providing a scientific basis for this Traditional Chinese Medicine practice. This study also presents a novel circuit design using an active filtering method. An operational amplifier with its differential features eliminates the interference from external signals, including the instant high-frequency noise. In addition, the system has the advantages of simple circuitry, cheap cost and high precision. PMID:25875192

  15. Performance analysis of low-complexity adaptive frequency-domain equalization and MIMO signal processing for compensation of differential mode group delay in mode-division multiplexing communication systems using few-mode fibers

    NASA Astrophysics Data System (ADS)

    Weng, Yi; He, Xuan; Pan, Zhongqi

    2016-02-01

    Mode-division multiplexing (MDM) transmission systems utilizing few-mode fibers (FMF) have been intensively explored to sustain continuous traffic growth. The key challenges of MDM systems are inter-modal crosstalk due to random mode coupling (RMC), and largely-accumulated differential mode group delay (DMGD), whilst hinders mode-demultiplexer implementation. The adaptive multi-input multi-output (MIMO) frequency-domain equalization (FDE) can dynamically compensate DMGD using digital signal processing (DSP) algorithms. The frequency-domain least-mean squares (FD-LMS) algorithm has been universally adopted for high-speed MDM communications, mainly for its relatively low computational complexity. However, longer training sequence is appended for FD-LMS to achieve faster convergence, which incurs prohibitively higher system overhead and reduces overall throughput. In this paper, we propose a fast-convergent single-stage adaptive frequency-domain recursive least-squares (FD-RLS) algorithm with reduced complexity for DMGD compensation at MDM coherent receivers. The performance and complexity comparison of FD-RLS, with signal-PSD-dependent FD-LMS method and conventional FD-LMS approach, are performed in a 3000 km six-mode transmission system with 65 ps/km DMGD. We explore the convergence speed of three adaptive algorithms, including the normalized mean-square-error (NMSE) per fast Fourier transform (FFT) block at 14-30 dB OSNR. The fast convergence of FD-RLS is exploited at the expense of slightly-increased necessary tap numbers for MIMO equalizers, and it can partially save the overhead of training sequence. Furthermore, we demonstrate adaptive FD-RLS can also be used for chromatic dispersion (CD) compensation without increasing the filter tap length, thus prominently reducing the DSP implementation complexity for MDM systems.

  16. Pulsed hydrojet

    DOEpatents

    Bohachevsky, I.O.; Torrey, M.D.

    1986-06-10

    An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.

  17. Modelling Multi-Pulse Population Dynamics from Ultrafast Spectroscopy

    PubMed Central

    van Wilderen, Luuk J. G. W.; Lincoln, Craig N.; van Thor, Jasper J.

    2011-01-01

    Current advanced laser, optics and electronics technology allows sensitive recording of molecular dynamics, from single resonance to multi-colour and multi-pulse experiments. Extracting the occurring (bio-) physical relevant pathways via global analysis of experimental data requires a systematic investigation of connectivity schemes. Here we present a Matlab-based toolbox for this purpose. The toolbox has a graphical user interface which facilitates the application of different reaction models to the data to generate the coupled differential equations. Any time-dependent dataset can be analysed to extract time-independent correlations of the observables by using gradient or direct search methods. Specific capabilities (i.e. chirp and instrument response function) for the analysis of ultrafast pump-probe spectroscopic data are included. The inclusion of an extra pulse that interacts with a transient phase can help to disentangle complex interdependent pathways. The modelling of pathways is therefore extended by new theory (which is included in the toolbox) that describes the finite bleach (orientation) effect of single and multiple intense polarised femtosecond pulses on an ensemble of randomly oriented particles in the presence of population decay. For instance, the generally assumed flat-top multimode beam profile is adapted to a more realistic Gaussian shape, exposing the need for several corrections for accurate anisotropy measurements. In addition, the (selective) excitation (photoselection) and anisotropy of populations that interact with single or multiple intense polarised laser pulses is demonstrated as function of power density and beam profile. Using example values of real world experiments it is calculated to what extent this effectively orients the ensemble of particles. Finally, the implementation includes the interaction with multiple pulses in addition to depth averaging in optically dense samples. In summary, we show that mathematical modelling is

  18. Spatiotemporal pulse shaping using resonant diffraction gratings.

    PubMed

    Golovastikov, Nikita V; Bykov, Dmitry A; Doskolovich, Leonid L

    2015-08-01

    We propose a new theoretical model describing spatiotemporal transformations of two-dimensional optical pulses by resonant diffraction gratings. The diffraction of the pulse is described in terms of a linear system. Simple analytical approximations for the transfer function and the impulse response of the system are derived. The derived approximations contain five independent parameters, which can be estimated using the rigorous coupled-wave analysis. The presented numerical simulation results demonstrate that the resonant grating can perform complex pulse transformations, such as the simultaneous spatial and temporal differentiation of the optical pulse envelope.

  19. Tolerance to LSD and DOB induced shaking behaviour: differential adaptations of frontocortical 5-HT(2A) and glutamate receptor binding sites.

    PubMed

    Buchborn, Tobias; Schröder, Helmut; Dieterich, Daniela C; Grecksch, Gisela; Höllt, Volker

    2015-03-15

    Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD) and dimethoxy-bromoamphetamine (DOB), provoke stereotype-like shaking behaviour in rodents, which is hypothesised to engage frontocortical glutamate receptor activation secondary to serotonin2A (5-HT2A) related glutamate release. Challenging this hypothesis, we here investigate whether tolerance to LSD and DOB correlates with frontocortical adaptations of 5-HT2A and/or overall-glutamate binding sites. LSD and DOB (0.025 and 0.25 mg/kg, i.p.) induce a ketanserin-sensitive (0.5 mg/kg, i.p., 30-min pretreatment) increase in shaking behaviour (including head twitches and wet dog shakes), which with repeated application (7× in 4 ds) is undermined by tolerance. Tolerance to DOB, as indexed by DOB-sensitive [(3)H]spiroperidol and DOB induced [(35)S]GTP-gamma-S binding, is accompanied by a frontocortical decrease in 5-HT2A binding sites and 5-HT2 signalling, respectively; glutamate-sensitive [(3)H]glutamate binding sites, in contrast, remain unchanged. As to LSD, 5-HT2 signalling and 5-HT2A binding, respectively, are not or only marginally affected, yet [(3)H]glutamate binding is significantly decreased. Correlation analysis interrelates tolerance to DOB to the reduced 5-HT2A (r=.80) as well as the unchanged [(3)H]glutamate binding sites (r=.84); tolerance to LSD, as opposed, shares variance with the reduction in [(3)H]glutamate binding sites only (r=.86). Given that DOB and LSD both induce tolerance, one correlating with 5-HT2A, the other with glutamate receptor adaptations, it might be inferred that tolerance can arise at either level. That is, if a hallucinogen (like LSD in our study) fails to induce 5-HT2A (down-)regulation, glutamate receptors (activated postsynaptic to 5-HT2A related glutamate release) might instead adapt and thus prevent further overstimulation of the cortex. PMID:25513973

  20. Tolerance to LSD and DOB induced shaking behaviour: differential adaptations of frontocortical 5-HT(2A) and glutamate receptor binding sites.

    PubMed

    Buchborn, Tobias; Schröder, Helmut; Dieterich, Daniela C; Grecksch, Gisela; Höllt, Volker

    2015-03-15

    Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD) and dimethoxy-bromoamphetamine (DOB), provoke stereotype-like shaking behaviour in rodents, which is hypothesised to engage frontocortical glutamate receptor activation secondary to serotonin2A (5-HT2A) related glutamate release. Challenging this hypothesis, we here investigate whether tolerance to LSD and DOB correlates with frontocortical adaptations of 5-HT2A and/or overall-glutamate binding sites. LSD and DOB (0.025 and 0.25 mg/kg, i.p.) induce a ketanserin-sensitive (0.5 mg/kg, i.p., 30-min pretreatment) increase in shaking behaviour (including head twitches and wet dog shakes), which with repeated application (7× in 4 ds) is undermined by tolerance. Tolerance to DOB, as indexed by DOB-sensitive [(3)H]spiroperidol and DOB induced [(35)S]GTP-gamma-S binding, is accompanied by a frontocortical decrease in 5-HT2A binding sites and 5-HT2 signalling, respectively; glutamate-sensitive [(3)H]glutamate binding sites, in contrast, remain unchanged. As to LSD, 5-HT2 signalling and 5-HT2A binding, respectively, are not or only marginally affected, yet [(3)H]glutamate binding is significantly decreased. Correlation analysis interrelates tolerance to DOB to the reduced 5-HT2A (r=.80) as well as the unchanged [(3)H]glutamate binding sites (r=.84); tolerance to LSD, as opposed, shares variance with the reduction in [(3)H]glutamate binding sites only (r=.86). Given that DOB and LSD both induce tolerance, one correlating with 5-HT2A, the other with glutamate receptor adaptations, it might be inferred that tolerance can arise at either level. That is, if a hallucinogen (like LSD in our study) fails to induce 5-HT2A (down-)regulation, glutamate receptors (activated postsynaptic to 5-HT2A related glutamate release) might instead adapt and thus prevent further overstimulation of the cortex.

  1. Cytokine and cytokine receptor genes of the adaptive immune response are differentially associated with breast cancer risk in American women of African and European ancestry.

    PubMed

    Quan, Lei; Gong, Zhihong; Yao, Song; Bandera, Elisa V; Zirpoli, Gary; Hwang, Helena; Roberts, Michelle; Ciupak, Gregory; Davis, Warren; Sucheston, Lara; Pawlish, Karen; Bovbjerg, Dana H; Jandorf, Lina; Cabasag, Citadel; Coignet, Jean-Gabriel; Ambrosone, Christine B; Hong, Chi-Chen

    2014-03-15

    Disparities in breast cancer biology are evident between American women of African ancestry (AA) and European ancestry (EA) and may be due, in part, to differences in immune function. To assess the potential role of constitutional host immunity on breast carcinogenesis, we tested associations between breast cancer risk and 47 single nucleotide polymorphisms (SNPs) in 26 cytokine-related genes of the adaptive immune system using 650 EA (n = 335 cases) and 864 AA (n = 458 cases) women from the Women's Circle of Health Study (WCHS). With additional participant accrual to the WCHS, promising SNPs from the initial analysis were evaluated in a larger sample size (1,307 EAs and 1,365 AAs). Multivariate logistic regression found SNPs in genes important for T helper type 1 (Th1) immunity (IFNGR2 rs1059293, IL15RA rs2296135, LTA rs1041981), Th2 immunity (IL4R rs1801275), and T regulatory cell-mediated immunosuppression (TGFB1 rs1800469) associated with breast cancer risk, mainly among AAs. The combined effect of these five SNPs was highly significant among AAs (P-trend = 0.0005). When stratified by estrogen receptor (ER) status, LTA rs1041981 was associated with ER-positive breast cancers among EAs and marginally among AAs. Only among AA women, IL15 rs10833 and IL15RA rs2296135 were associated with ER-positive tumors, and IL12RB1 rs375947, IL15 rs10833 and TGFB1 rs1800469 were associated with ER-negative tumors. Our study systematically identified genetic variants in the adaptive immune response pathway associated with breast cancer risk, which appears to differ by ancestry groups, menopausal status and ER status.

  2. Monocytes/Macrophages Upregulate the Hyaluronidase HYAL1 and Adapt Its Subcellular Trafficking to Promote Extracellular Residency upon Differentiation into Osteoclasts

    PubMed Central

    Puissant, Emeline; Boonen, Marielle

    2016-01-01

    Osteoclasts are giant bone-resorbing cells originating from monocytes/macrophages. During their differentiation, they overexpress two lysosomal enzymes, cathepsin K and TRAP, which are secreted into the resorption lacuna, an acidified sealed area in contact with bone matrix where bone degradation takes place. Here we report that the acid hydrolase HYAL1, a hyaluronidase able to degrade the glycosaminoglycans hyaluronic acid (HA) and chondroitin sulfate, is also upregulated upon osteoclastogenesis. The mRNA expression and protein level of HYAL1 are markedly increased in osteoclasts differentiated from RAW264.7 mouse macrophages or primary mouse bone marrow monocytes compared to these precursor cells. As a result, the HYAL1-mediated HA hydrolysis ability of osteoclasts is strongly enhanced. Using subcellular fractionation, we demonstrate that HYAL1 proteins are sorted to the osteoclast lysosomes even though, in contrast to cathepsin K and TRAP, HYAL1 is poorly mannose 6-phosphorylated. We reported previously that macrophages secrete HYAL1 proforms by constitutive secretion, and that these are recaptured by the cell surface mannose receptor, processed in endosomes and sorted to lysosomes. Present work highlights that osteoclasts secrete HYAL1 in two ways, through lysosomal exocytosis and constitutive secretion, and that these cells promote the extracellular residency of HYAL1 through downregulation of the mannose receptor. Interestingly, the expression of the other main hyaluronidase, HYAL2, and of lysosomal exoglycosidases involved in HA degradation, does not increase similarly to HYAL1 upon osteoclastogenesis. Taken together, these findings point out the predominant involvement of HYAL1 in bone HA metabolism and perhaps bone remodeling via the resorption lacuna. PMID:27755597

  3. Adaptive Optics Communications Performance Analysis

    NASA Technical Reports Server (NTRS)

    Srinivasan, M.; Vilnrotter, V.; Troy, M.; Wilson, K.

    2004-01-01

    The performance improvement obtained through the use of adaptive optics for deep-space communications in the presence of atmospheric turbulence is analyzed. Using simulated focal-plane signal-intensity distributions, uncoded pulse-position modulation (PPM) bit-error probabilities are calculated assuming the use of an adaptive focal-plane detector array as well as an adaptively sized single detector. It is demonstrated that current practical adaptive optics systems can yield performance gains over an uncompensated system ranging from approximately 1 dB to 6 dB depending upon the PPM order and background radiation level.

  4. PULSE COLUMN

    DOEpatents

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  5. SU-E-T-558: An Exploratory RF Pulse Sequence Technique Used to Induce Differential Heating in Tissues Containing Iron Oxide Nanoparticles for a Possible Hyperthermic Adjuvant Effect to Radiotherapy

    SciTech Connect

    Yee, S; Ionascu, D; Wilson, G; Thapa, R

    2014-06-01

    Purpose: In pre-clinical trials of cancer thermotherapy, hyperthermia can be induced by exposing localized super-paramagnetic iron oxide nanoparticles (SPION) to external alternating magnetic fields generated by a solenoid electrical circuit (Zhao et al., Theranostics 2012). Alternatively, an RF pulse technique implemented in a regular MRI system is explored as a possible hyperthermia induction technique . Methods: A new thermal RF pulse sequence was developed using the Philips pulse programming tool for the 3T Ingenia MRI system to provide a sinusoidal magnetic field alternating at the frequency of 1.43 kHz (multiples of sine waves of 0.7 ms period) before each excitation RF pulse for imaging. The duration of each thermal RF pulse routine was approximately 3 min, and the thermal pulse was applied multiple times to a phantom that contains different concentrations (high, medium and low) of SPION samples. After applying the thermal pulse each time, the temperature change was estimated by measuring the phase changes in the T1-weighted inversion-prepared multi-shot turbo field echo (TFE) sequence (TR=5.5 ms, TE=2.7 ms, inversion time=200 ms). Results: The phase values and relative differences among them changed as the number of applied thermal RF pulses increased. After the 5th application of the thermal RF pulse, the relative phase differences increased significantly, suggesting the thermal activation of the SPION. The increase of the phase difference was approximately linear with the SPION concentration. Conclusion: A sinusoidal RF pulse from the MRI system may be utilized to selectively thermally activate tissues containing super-paramagnetic iron oxide nanoparticles.

  6. Adaptive network countermeasures.

    SciTech Connect

    McClelland-Bane, Randy; Van Randwyk, Jamie A.; Carathimas, Anthony G.; Thomas, Eric D.

    2003-10-01

    This report describes the results of a two-year LDRD funded by the Differentiating Technologies investment area. The project investigated the use of countermeasures in protecting computer networks as well as how current countermeasures could be changed in order to adapt with both evolving networks and evolving attackers. The work involved collaboration between Sandia employees and students in the Sandia - California Center for Cyber Defenders (CCD) program. We include an explanation of the need for adaptive countermeasures, a description of the architecture we designed to provide adaptive countermeasures, and evaluations of the system.

  7. Tapered pulse tube for pulse tube refrigerators

    DOEpatents

    Swift, Gregory W.; Olson, Jeffrey R.

    1999-01-01

    Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

  8. Differential adaptations between cold-stenothermal environments in the bivalve Lissarca cf. miliaris (Philobryidae) from the Scotia Sea islands and Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Reed, Adam J.; Linse, Katrin; Thatje, Sven

    2014-04-01

    The cold stenothermal nature of the Southern Ocean, and highly adapted fauna living within, raises the question of how much intra-specific variation there is among invertebrate populations, and how variation may have a role in speciation processes through ecological divergence, natural selection, and reproductive isolation. Despite decades of collecting biological material, this question remains largely unanswered, and many studies compare ‘populations' of pooled material from wide geographic ranges to compensate for sampling constraints. In this study, variations in ecophysiological traits are explored by measuring growth, reproduction, and shell morphology among six populations of the small bivalve Lissarca cf. miliaris (Philippi, 1845) from the Southern Ocean, which experience subtle differences in temperature, disturbance, and food availability. There are significant differences in shell morphology and growth among different populations and slower growth rates at higher latitude populations. Prodissoconch sizes show an inverse ‘U' shaped relationship with latitude, and are correlated with egg size at South Georgia and King George Island's Potter Cove. Higher brood sizes at the South Georgia population represent a trade-off with lower egg size, and correlate with shell morphology by offering lower internal capacity to brood young. Lower investment into offspring and morphological variations in L. cf. miliaris highlight the importance of local scale environmental variations on species' ecology. These variations in physical traits appear to be underestimated in the Southern Ocean, but may be important drivers of ecological divergence and speciation, which should be considered in future genetic investigations on different invertebrate populations.

  9. Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees

    NASA Astrophysics Data System (ADS)

    El Yaacoubi, Adnane; Malagi, Gustavo; Oukabli, Ahmed; Citadin, Idemir; Hafidi, Majida; Bonhomme, Marc; Legave, Jean-Michel

    2016-04-01

    Few studies have focused on the characterization of bud dormancy and growth dynamics for temperate fruit species in temperate and mild cropping areas, although this is an appropriate framework to anticipate phenology adaptation facing future warming contexts which would potentially combine chill declines and heat increases. To examine this issue, two experimental approaches and field observations were used for high- and low-chill apple cultivars in temperate climate of southern France and in mild climates of northern Morocco and southern Brazil. Low-chill almond cultivars offered an additional relevant plant material for comparison with apple in northern Morocco. Divergent patterns of dormancy and growth dynamics were clearly found in apple tree between southern France and southern Brazil. Divergences were less pronounced between France and Morocco. A global view outlined main differences in the dormancy chronology and intensity, the transition between endordormancy and ecodormancy and the duration of ecodormancy. A key role of bud rehydration in the transition period was shown. High-chill cultivars would be submitted in mild conditions to heterogeneous rehydration capacities linked to insufficient chill fulfillment and excessive forcing linked to high temperatures. This would favor bud competitions and consequently excessive flowering durations and weak flowering. Low chilling requirements in apple and almond would conversely confer biological capacities to tolerate superficial dormancy and abrupt transition from endordormancy to ecodormancy without important heterogeneous rehydration states within buds. It may also assume that low-chill cultivars can also tolerate high temperatures during ecodormancy as well as extended flowering durations.

  10. A SNP in the HSP90AA1 gene 5' flanking region is associated with the adaptation to differential thermal conditions in the ovine species.

    PubMed

    Marcos-Carcavilla, Ane; Mutikainen, Mari; González, Carmen; Calvo, Jorge H; Kantanen, Juha; Sanz, Albina; Marzanov, Nurbiy S; Pérez-Guzmán, María D; Serrano, Magdalena

    2010-01-01

    Molecular chaperones have long been understood to be preferentially transcribed in response to multiple perturbations of the cellular homeostasis. In this study, several polymorphisms in the gene encoding the inducible form of the cytoplasmic Hsp90 (HSP90AA1) were addressed in 24 sheep breeds reared in different climatic regions of Europe, Africa, and Asia. Significant differences in the genotype frequencies for a C/G single nucleotide polymorphism (SNP) located at position -660 in the HSP90AA1 5'flanking region were found between the different breeds. Regression analyses reflected significant correlations (from 0.41 to 0.62) between the alternative genotypes of this polymorphism and several climatic and geographic variables characteristic of the regions where these breeds are reared. Real-time analysis revealed that animals bearing the CC(-660) genotype presented higher expression levels than those presenting the CG(-660) or GG(-660) in summer, but not in spring. Mutation at -660 site seems to affect HSP90AA1 transcription rates which could have important effects on the adaptation to different environmental conditions in sheep. Thus, the variability found in the genotype frequencies for the SNP at -660 in the ovine HSP90AA1 locus could be the result of the different environmental pressures occurring in the regions where these breed are maintained.

  11. A SNP in the HSP90AA1 gene 5′ flanking region is associated with the adaptation to differential thermal conditions in the ovine species

    PubMed Central

    Marcos-Carcavilla, Ane; Mutikainen, Mari; González, Carmen; Calvo, Jorge H.; Kantanen, Juha; Sanz, Albina; Marzanov, Nurbiy S.; Pérez-Guzmán, María D.

    2009-01-01

    Molecular chaperones have long been understood to be preferentially transcribed in response to multiple perturbations of the cellular homeostasis. In this study, several polymorphisms in the gene encoding the inducible form of the cytoplasmic Hsp90 (HSP90AA1) were addressed in 24 sheep breeds reared in different climatic regions of Europe, Africa, and Asia. Significant differences in the genotype frequencies for a C/G single nucleotide polymorphism (SNP) located at position −660 in the HSP90AA1 5′flanking region were found between the different breeds. Regression analyses reflected significant correlations (from 0.41 to 0.62) between the alternative genotypes of this polymorphism and several climatic and geographic variables characteristic of the regions where these breeds are reared. Real-time analysis revealed that animals bearing the CC−660 genotype presented higher expression levels than those presenting the CG−660 or GG−660 in summer, but not in spring. Mutation at −660 site seems to affect HSP90AA1 transcription rates which could have important effects on the adaptation to different environmental conditions in sheep. Thus, the variability found in the genotype frequencies for the SNP at −660 in the ovine HSP90AA1 locus could be the result of the different environmental pressures occurring in the regions where these breed are maintained. Electronic supplementary material The online version of this article (doi:10.1007/s12192-009-0123-z) contains supplementary material, which is available to authorized users. PMID:19496025

  12. Monocular and binocular mechanisms mediating flicker adaptation.

    PubMed

    Zhuang, Xiaohua; Shevell, Steven K

    2015-12-01

    Flicker adaptation reduces subsequent temporal contrast sensitivity. Recent studies show that this adaptation likely results from neural changes in the magnocellular visual pathway, but whether this adaptation occurs at a monocular or a binocular level, or both, is unclear. Here, two experiments address this question. The first experiment exploits the observation that flicker adaptation is stronger at higher than lower temporal frequencies. Observers' two eyes adapted to 3Hz flicker with an incremental pulse at 1/4 duty cycle, either in-phase or out-of-phase in the two eyes. At the binocular level, the flicker rate was 6Hz in the out-of-phase condition if the two eyes' pulse trains sum. Similar sensitivity reduction was found in both phase conditions, as expected for independent monocular adapting mechanisms. The second experiment tested for interocular transfer of adaptation between eyes. Results showed that (1) flicker adaptation was strongest with adapting and test fields in only the same eye, (2) adaptation can be partially transferred interocularly with adaptation in only the opposite eye, and (3) adaptation was weakened when both eyes were adapted simultaneously at different contrasts, compared to test-eye adaptation alone. Taken together, the findings are consistent with mechanisms of flicker adaptation at both the monocular and binocular level. PMID:26505684

  13. Adapted chondrogenic differentiation of human mesenchymal stem cells via controlled release of TGF-β1 from poly(ethylene oxide)-terephtalate/poly(butylene terepthalate) multiblock scaffolds.

    PubMed

    Rey-Rico, Ana; Venkatesan, Jagadeesh K; Sohier, Jerome; Moroni, Lorenzo; Cucchiarini, Magali; Madry, Henning

    2015-01-01

    Controlled release of TGF-β1 from scaffolds is an attractive mechanism to modulate the chondrogenesis of human bone marrow mesenchymal stem cells (hBMSCs) that repopulate articular cartilage defects. Here, we evaluated the ability of porous scaffolds composed of poly(ethylene oxide)-terephtalate and poly(butylene terepthalate) (PEOT/PBT) to release bioactive TGF-β1 for chondrogenesis of hBMSCs in a pellet culture model. Chondroinduction was compared with that promoted by direct addition of the recombinant factor to the culture medium. The data show a controlled release of TGF-β1 from scaffolds for at least 21 days in vitro, with ∼10% of TGF-β1 released during this period. The delivered TGF-β1 was bioactive, as confirmed by successful chondrogenic differentiation of hBMSCs monitored by morphological, histological, immunohistochemical, biochemical, and real-time reverse transcription polymerase chain reaction analyses. Third, semiquantitative histological evaluations revealed a similar pattern of chondrogenesis compared with the positive controls. Importantly, TGF-β1-loaded scaffolds allowed for a ∼700-fold upregulation of type-II collagen mRNA compared to when pellets were maintained in the presence of the soluble TGF-β1, reflected also in the highest score of immunoreactivity to type-II collagen, not significantly different from the positive controls. Likewise, aggrecan mRNA was ∼200-fold upregulated. Interestingly, most (>94%) of the glycosaminoglycan produced remaining associated with the pellets. Analysis of hypertrophic events showed no significant difference in the average total hypertrophy score compared with the positive controls. These results demonstrate the suitability of controlled TGF-β1 release from biocompatible scaffolds to promote hBMSC chondrogenesis at a physical distance and in the absence of soluble TGF-β1. PMID:24665073

  14. Compensated pulsed alternator

    DOEpatents

    Weldon, William F.; Driga, Mircea D.; Woodson, Herbert H.

    1980-01-01

    This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

  15. Adaptive cancellation techniques

    NASA Astrophysics Data System (ADS)

    1983-11-01

    An adaptive signal canceller has been evaluated for the enhancement of pulse signal reception during the transmission of a high power ECM jamming signal. The canceller design is based on the use of DRFM(Digital RF Memory) technology as part of an adaptive multiple tapped delay line. The study includes analysis of relationship of tap spacing and waveform bandwidth, survey of related documents in areas of sidelobe cancellers, transversal equalizers, and adaptive filters, and derivation of control equations and corresponding control processes. The simulation of overall processes included geometric analysis of the multibeam transmitting antenna, multiple reflection sources and the receiving antenna; waveforms, tap spacings and bandwidths; and alternate control algorithms. Conclusions are provided regarding practical system control algorithms, design characteristics and limitations.

  16. Optimal pulse tube volume design in GM-type pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Jung, Jeheon; Jeong, Sangkwon

    2007-09-01

    For given compression work, a GM-type pulse tube refrigerator can be designed to operate with large pressure swing and small shuttle mass (small pulse tube volume) or with small pressure swing and large shuttle mass (large pulse tube volume). In this paper, the refrigeration performance analysis is carried out by quantitatively evaluating the concurrent pressure swing and the shuttle mass in the pulse tube. The analysis result of the GM-type pulse tube refrigerator shows that the design of large pressure swing and small shuttle mass is a preferable one. In a practical case, however, a helium compressor has a certain limit in differential pressure between supply and return and, accordingly, the achievable pressure swing in GM-type pulse tube refrigerator is also limited. From this limit-point of the differential pressure, the volume reduction of the pulse tube does not lead to the intensification of the differential pressure any further. The refrigerator performance begins to decrease beyond this point. The differential pressure limit-point, as a consequence, is considered as the optimal design point.

  17. Pulse speed on a plucked wire

    NASA Astrophysics Data System (ADS)

    Odekirk, Tristan; Slaton, William V.

    2012-04-01

    This paper serves to update an elegant experiment published in The Physics Teacher to measure the speed of a pulse on a taut metal wire. Unfortunately, commercially available units2 that serve the same purpose are priced outside the range of most high school or college physics teaching laboratories. Wakeland et al. show how an affordable adaptation of the traditional standing wave apparatus using taut metal wire and horseshoe magnets can be used to measure the speed of a pulse by using an oscilloscope to measure an induced voltage in the wire as the pulse transverses the middle of the magnets, which are a known distance apart.

  18. From reactors to long pulse sources

    SciTech Connect

    Mezei, F. |

    1995-12-31

    We will show, that by using an adapted instrumentation concept, the performance of a continuous source can be emulated by one switch on in long pulses for only about 10% of the total time. This 10 fold gain in neutron economy opens up the way for building reactor like sources with an order of magnitude higher flux than the present technological limits. Linac accelerator driven spallation lends itself favorably for the realization of this kind of long pulse sources, which will be complementary to short pulse spallation sources, the same way continuous reactor sources are.

  19. Adaptive Management

    EPA Science Inventory

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive managem...

  20. Long pulse production from short pulses

    DOEpatents

    Toeppen, John S.

    1994-01-01

    A method of producing a long output pulse (SA) from a short pump pulse (P), using an elongated amplified fiber (11) having a doped core (12) that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding 13. A seed beam (S) of the longer wavelength is injected into the core (12) at one end of the fiber (11) and a pump pulse (P) of the shorter wavelength is injected into the cladding (13) at the other end of the fiber (11). The counter-propagating seed beam (S) and pump pulse (P) will produce an amplified output pulse (SA) having a time duration equal to twice the transit time of the pump pulse (P) through the fiber (11) plus the length of the pump pulse (P).

  1. Long pulse production from short pulses

    DOEpatents

    Toeppen, J.S.

    1994-08-02

    A method of producing a long output pulse from a short pump pulse is disclosed, using an elongated amplified fiber having a doped core that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding. A seed beam of the longer wavelength is injected into the core at one end of the fiber and a pump pulse of the shorter wavelength is injected into the cladding at the other end of the fiber. The counter-propagating seed beam and pump pulse will produce an amplified output pulse having a time duration equal to twice the transit time of the pump pulse through the fiber plus the length of the pump pulse. 3 figs.

  2. Local Adaptation in Marine Invertebrates

    NASA Astrophysics Data System (ADS)

    Sanford, Eric; Kelly, Morgan W.

    2011-01-01

    Local adaptation in the sea was regarded historically as a rare phenomenon that was limited to a handful of species with exceptionally low dispersal potential. However, a growing body of experimental studies indicates that adaptive differentiation occurs in numerous marine invertebrates in response to selection imposed by strong gradients (and more complex mosaics) of abiotic and biotic conditions. Moreover, a surprisingly high proportion of the marine invertebrates known or suspected of exhibiting local adaptation are species with planktonic dispersal. Adaptive divergence among populations can occur over a range of spatial scales, including those that are fine-grained (i.e., meters to kilometers), reflecting a balance between scales of gene flow and selection. Addressing the causes and consequences of adaptive genetic differentiation among invertebrate populations promises to advance community ecology, climate change research, and the effective management of marine ecosystems.

  3. Odorant concentration differentiator for intermittent olfactory signals.

    PubMed

    Fujiwara, Terufumi; Kazawa, Tomoki; Sakurai, Takeshi; Fukushima, Ryota; Uchino, Keiro; Yamagata, Tomoko; Namiki, Shigehiro; Haupt, Stephan Shuichi; Kanzaki, Ryohei

    2014-12-10

    Animals need to discriminate differences in spatiotemporally distributed sensory signals in terms of quality as well as quantity for generating adaptive behavior. Olfactory signals characterized by odor identity and concentration are intermittently distributed in the environment. From these intervals of stimulation, animals process odorant concentration to localize partners or food sources. Although concentration-response characteristics in olfactory neurons have traditionally been investigated using single stimulus pulses, their behavior under intermittent stimulus regimens remains largely elusive. Using the silkmoth (Bombyx mori) pheromone processing system, a simple and behaviorally well-defined model for olfaction, we investigated the neuronal representation of odorant concentration upon intermittent stimulation in the naturally occurring range. To the first stimulus in a series, the responses of antennal lobe (AL) projection neurons (PNs) showed a concentration dependence as previously shown in many olfactory systems. However, PN response amplitudes dynamically changed upon exposure to intermittent stimuli of the same odorant concentration and settled to a constant, largely concentration-independent level. As a result, PN responses emphasized odorant concentration changes rather than encoding absolute concentration in pulse trains of stimuli. Olfactory receptor neurons did not contribute to this response transformation which was due to long-lasting inhibition affecting PNs in the AL. Simulations confirmed that inhibition also provides advantages when stimuli have naturalistic properties. The primary olfactory center thus functions as an odorant concentration differentiator to efficiently detect concentration changes, thereby improving odorant source orientation over a wide concentration range.

  4. Fireplace adapters

    SciTech Connect

    Hunt, R.L.

    1983-12-27

    An adapter is disclosed for use with a fireplace. The stove pipe of a stove standing in a room to be heated may be connected to the flue of the chimney so that products of combustion from the stove may be safely exhausted through the flue and outwardly of the chimney. The adapter may be easily installed within the fireplace by removing the damper plate and fitting the adapter to the damper frame. Each of a pair of bolts has a portion which hooks over a portion of the damper frame and a threaded end depending from the hook portion and extending through a hole in the adapter. Nuts are threaded on the bolts and are adapted to force the adapter into a tight fit with the adapter frame.

  5. Pulsed power supply for an electrostatic precipitator

    SciTech Connect

    Santamaria, G.T.

    1986-07-15

    An electrostatic precipitator power supply circuit is described for generating voltage pulses on the precipitator while allowing a residual collection voltage to be retained on the precipitator during intervals between pulses, where the voltage of the pulses is substantially in excess of the residual voltage, the power supply circuit comprising: means for generating the high voltage pulses at the secondary inductance of a step-up transformer by discharging a capacitor through the primary inductance of the step-up transformer; the electrostatic precipitator connected to the secondary inductance of the step-up transformer to receive the high voltage pulses; and means for returning a portion of the high voltage pulses to the capacitor, and for maintaining the residual voltage on the precipitator during interpulse periods including means with a variable impedance adapted for providing a maximum impedance during interpulse periods and a minimum impedance during high voltage pulses and means for causing the variable impedance means to exhibit a minimum impedance during the return of a portion of the high voltage pulses.

  6. Adaptive Algebraic Multigrid Methods

    SciTech Connect

    Brezina, M; Falgout, R; MacLachlan, S; Manteuffel, T; McCormick, S; Ruge, J

    2004-04-09

    Our ability to simulate physical processes numerically is constrained by our ability to solve the resulting linear systems, prompting substantial research into the development of multiscale iterative methods capable of solving these linear systems with an optimal amount of effort. Overcoming the limitations of geometric multigrid methods to simple geometries and differential equations, algebraic multigrid methods construct the multigrid hierarchy based only on the given matrix. While this allows for efficient black-box solution of the linear systems associated with discretizations of many elliptic differential equations, it also results in a lack of robustness due to assumptions made on the near-null spaces of these matrices. This paper introduces an extension to algebraic multigrid methods that removes the need to make such assumptions by utilizing an adaptive process. The principles which guide the adaptivity are highlighted, as well as their application to algebraic multigrid solution of certain symmetric positive-definite linear systems.

  7. Chirped-pulse amplification with narrowband pulses.

    PubMed

    Shverdin, M Y; Albert, F; Anderson, S G; Betts, S M; Gibson, D J; Messerly, M J; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-15

    We demonstrate a compact hyperdispersion stretcher and compressor pair that permit chirped-pulse amplification in Nd:YAG. We generate 750 mJ, 0.2 nm FWHM, 10 Hz pulses recompressed to an 8 ps near-transform-limited duration. The dispersion-matched pulse compressor and stretcher impart a chirp of 7300 ps/nm, in a 3 m x 1 m footprint.

  8. Chirped-pulse amplification with narrowband pulses.

    PubMed

    Shverdin, M Y; Albert, F; Anderson, S G; Betts, S M; Gibson, D J; Messerly, M J; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-15

    We demonstrate a compact hyperdispersion stretcher and compressor pair that permit chirped-pulse amplification in Nd:YAG. We generate 750 mJ, 0.2 nm FWHM, 10 Hz pulses recompressed to an 8 ps near-transform-limited duration. The dispersion-matched pulse compressor and stretcher impart a chirp of 7300 ps/nm, in a 3 m x 1 m footprint. PMID:20634869

  9. Adaptive SPECT

    PubMed Central

    Barrett, Harrison H.; Furenlid, Lars R.; Freed, Melanie; Hesterman, Jacob Y.; Kupinski, Matthew A.; Clarkson, Eric; Whitaker, Meredith K.

    2008-01-01

    Adaptive imaging systems alter their data-acquisition configuration or protocol in response to the image information received. An adaptive pinhole single-photon emission computed tomography (SPECT) system might acquire an initial scout image to obtain preliminary information about the radiotracer distribution and then adjust the configuration or sizes of the pinholes, the magnifications, or the projection angles in order to improve performance. This paper briefly describes two small-animal SPECT systems that allow this flexibility and then presents a framework for evaluating adaptive systems in general, and adaptive SPECT systems in particular. The evaluation is in terms of the performance of linear observers on detection or estimation tasks. Expressions are derived for the ideal linear (Hotelling) observer and the ideal linear (Wiener) estimator with adaptive imaging. Detailed expressions for the performance figures of merit are given, and possible adaptation rules are discussed. PMID:18541485

  10. Adaptive Computing.

    ERIC Educational Resources Information Center

    Harrell, William

    1999-01-01

    Provides information on various adaptive technology resources available to people with disabilities. (Contains 19 references, an annotated list of 129 websites, and 12 additional print resources.) (JOW)

  11. Contour adaptation.

    PubMed

    Anstis, Stuart

    2013-01-01

    It is known that adaptation to a disk that flickers between black and white at 3-8 Hz on a gray surround renders invisible a congruent gray test disk viewed afterwards. This is contrast adaptation. We now report that adapting simply to the flickering circular outline of the disk can have the same effect. We call this "contour adaptation." This adaptation does not transfer interocularly, and apparently applies only to luminance, not color. One can adapt selectively to only some of the contours in a display, making only these contours temporarily invisible. For instance, a plaid comprises a vertical grating superimposed on a horizontal grating. If one first adapts to appropriate flickering vertical lines, the vertical components of the plaid disappears and it looks like a horizontal grating. Also, we simulated a Cornsweet (1970) edge, and we selectively adapted out the subjective and objective contours of a Kanisza (1976) subjective square. By temporarily removing edges, contour adaptation offers a new technique to study the role of visual edges, and it demonstrates how brightness information is concentrated in edges and propagates from them as it fills in surfaces.

  12. A heme oxygenase isoform is essential for aerobic growth in the cyanobacterium Synechocystis sp. PCC 6803: modes of differential operation of two isoforms/enzymes to adapt to low oxygen environments in cyanobacteria.

    PubMed

    Aoki, Rina; Goto, Takeaki; Fujita, Yuichi

    2011-10-01

    Heme oxygenase (HO) catalyzes the oxygen-dependent cleavage of heme to produce biliverdin IXα in phycobilin biosynthesis. In the genome of the cyanobacterium Synechocystis sp. PCC 6803 there are two genes, ho1 (sll1184) and ho2 (sll1875), encoding HO isoforms. Reverse transcription-PCR indicated that ho1 is constitutively expressed, and ho2 is induced under micro-oxic conditions. A mutant lacking ho1 (Δho1) failed to grow under aerobic conditions while it did grow at a significantly slower rate than the wild type under anaerobic (micro-oxic) conditions. When micro-oxically grown Δho1 was incubated under aerobic conditions, the cells underwent chlorosis with a significant decrease in phycocyanin accompanied by anomalous accumulation of protoporphyrin IX. These results suggested that HO1 is essential for aerobic growth as the sole HO and is dispensable under micro-oxic conditions. A mutant lacking ho2 (Δho2) grew under both aerobic and micro-oxic conditions like the wild type at low light intensity (50 μmol(photon) m⁻² s⁻¹). At higher light intensity (120 μmol(photon) m⁻² s⁻¹) the Δho2 mutant showed significant growth retardation under micro-oxic conditions. It is suggested that HO2 operates as a dominant HO under high light and micro-oxic environments and acts as an accessory HO at low light intensity. Constitutive expression of HO2 in a neutral site of the chromosome restored aerobic growth of Δho1, suggesting that HO2 has an activity high enough to substitute for HO1 under aerobic conditions. The differential operation of two isoforms/enzymes in cyanobacterial tetrapyrrole biosynthesis to adapt to low oxygen environments is discussed, including three other reactions.

  13. Adaptive Weibull Multiplicative Model and Multilayer Perceptron neural networks for dark-spot detection from SAR imagery.

    PubMed

    Taravat, Alireza; Oppelt, Natascha

    2014-12-02

    Oil spills represent a major threat to ocean ecosystems and their environmental status. Previous studies have shown that Synthetic Aperture Radar (SAR), as its recording is independent of clouds and weather, can be effectively used for the detection and classification of oil spills. Dark formation detection is the first and critical stage in oil-spill detection procedures. In this paper, a novel approach for automated dark-spot detection in SAR imagery is presented. A new approach from the combination of adaptive Weibull Multiplicative Model (WMM) and MultiLayer Perceptron (MLP) neural networks is proposed to differentiate between dark spots and the background. The results have been compared with the results of a model combining non-adaptive WMM and pulse coupled neural networks. The presented approach overcomes the non-adaptive WMM filter setting parameters by developing an adaptive WMM model which is a step ahead towards a full automatic dark spot detection. The proposed approach was tested on 60 ENVISAT and ERS2 images which contained dark spots. For the overall dataset, an average accuracy of 94.65% was obtained. Our experimental results demonstrate that the proposed approach is very robust and effective where the non-adaptive WMM & pulse coupled neural network (PCNN) model generates poor accuracies.

  14. Adaptive Weibull Multiplicative Model and Multilayer Perceptron Neural Networks for Dark-Spot Detection from SAR Imagery

    PubMed Central

    Taravat, Alireza; Oppelt, Natascha

    2014-01-01

    Oil spills represent a major threat to ocean ecosystems and their environmental status. Previous studies have shown that Synthetic Aperture Radar (SAR), as its recording is independent of clouds and weather, can be effectively used for the detection and classification of oil spills. Dark formation detection is the first and critical stage in oil-spill detection procedures. In this paper, a novel approach for automated dark-spot detection in SAR imagery is presented. A new approach from the combination of adaptive Weibull Multiplicative Model (WMM) and MultiLayer Perceptron (MLP) neural networks is proposed to differentiate between dark spots and the background. The results have been compared with the results of a model combining non-adaptive WMM and pulse coupled neural networks. The presented approach overcomes the non-adaptive WMM filter setting parameters by developing an adaptive WMM model which is a step ahead towards a full automatic dark spot detection. The proposed approach was tested on 60 ENVISAT and ERS2 images which contained dark spots. For the overall dataset, an average accuracy of 94.65% was obtained. Our experimental results demonstrate that the proposed approach is very robust and effective where the non-adaptive WMM & pulse coupled neural network (PCNN) model generates poor accuracies. PMID:25474376

  15. Laser pulse stacking method

    DOEpatents

    Moses, E.I.

    1992-12-01

    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

  16. Nerve-pulse interactions

    SciTech Connect

    Scott, A.C.

    1982-01-01

    Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.

  17. Pulse thermal energy transport/storage system

    DOEpatents

    Weislogel, Mark M.

    1992-07-07

    A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

  18. Plant N capture from pulses: effects of pulse size, growth rate, and other soil resources.

    PubMed

    James, J J; Richards, J H

    2005-08-01

    In arid ecosystems, the ability to rapidly capture nitrogen (N) from brief pulses is expected to influence plant growth, survival, and competitive ability. Theory and data suggest that N capture from pulses should depend on plant growth rate and availability of other limiting resources. Theory also predicts trade-offs in plant stress tolerance and ability to capture N from different size pulses. We injected K15NO3, to simulate small and large N pulses at three different times during the growing season into soil around the co-dominant Great Basin species Sarcobatus vermiculatus, Chrysothamnus nauseosus ssp. consimilis, and Distichlis spicata. Soils were amended with water and P in a partial factorial design. As predicted, all study species showed a comparable decline in N capture from large pulses through the season as growth rates slowed. Surprisingly, however, water and P availability differentially influenced the ability of these species to capture N from pulses. Distichlis N capture increased up to tenfold with water addition while Chrysothamnus N capture increased up to threefold with P addition. Sarcobatus N capture was not affected by water or P availability. Opposite to our prediction, Sarcobatus, the most stress tolerant species, captured less N from small pulses but more N from large pulses relative to the other species. These observations suggest that variation in N pulse timing and size can interact with variable soil water and P supply to determine how N is partitioned among co-existing Great Basin species.

  19. Pulse to pulse klystron diagnosis system

    SciTech Connect

    Nowak, J.; Davidson, V.; Genova, L.; Johnson, R.; Reagan, D.

    1981-03-01

    This report describes a system used to study the behavior of SLAC high powered klystrons operating with a twice normal pulse width of 5 ..mu..s. At present, up to eight of the klystrons installed along the accelerator can be operated with long pulses and monitored by this system. The report will also discuss some of the recent findings and investigations.

  20. Overview of the market and consumption of pulses in Europe.

    PubMed

    Schneider, Anne V C

    2002-12-01

    The human consumption of grain legumes and pulses in Europe and the EU is lower than in other regions of the world. However, there is a lot of variation between countries and an overall slight increase has been observed in recent years. The major trends in the EU pulse market are illustrated here with a specific focus on Spain, France and the UK, which account for about 60 % of the EU pulse consumption. The ways in which pulses are consumed are very different in the various EU countries, due to different regional food habits and traditions, and to differences in the supplies of grain legumes and the markets. Canned products dominate pulse sales compared with dry pulses sold in packets. Dry beans are the most consumed of the pulses in the EU, but the preference between species varies according to country. The factors limiting the consumption of pulses in the EU are mainly: an inadequate level of innovation for developing products adapted to modern life, a small home supply of pulses and competition from cheaper low-quality imports. Recently, however, consumers are favouring healthy and balanced vegetable diets. Pulses have significant nutritional and health advantages for consumers and their cultivation has a positive impact on agriculture and the environment. Therefore the trend in the consumption of pulses could change, especially if publicity about the benefits of pulses is improved and if the food industry and professional organizations take up the challenge to incorporate grain legumes in novel, convenient and healthy food products.

  1. Climate adaptation

    NASA Astrophysics Data System (ADS)

    Kinzig, Ann P.

    2015-03-01

    This paper is intended as a brief introduction to climate adaptation in a conference devoted otherwise to the physics of sustainable energy. Whereas mitigation involves measures to reduce the probability of a potential event, such as climate change, adaptation refers to actions that lessen the impact of climate change. Mitigation and adaptation differ in other ways as well. Adaptation does not necessarily have to be implemented immediately to be effective; it only needs to be in place before the threat arrives. Also, adaptation does not necessarily require global, coordinated action; many effective adaptation actions can be local. Some urban communities, because of land-use change and the urban heat-island effect, currently face changes similar to some expected under climate change, such as changes in water availability, heat-related morbidity, or changes in disease patterns. Concern over those impacts might motivate the implementation of measures that would also help in climate adaptation, despite skepticism among some policy makers about anthropogenic global warming. Studies of ancient civilizations in the southwestern US lends some insight into factors that may or may not be important to successful adaptation.

  2. SPIDER: A decade of measuring ultrashort pulses

    NASA Astrophysics Data System (ADS)

    Anderson, M. E.; Monmayrant, A.; Gorza, S.-P.; Wasylczyk, P.; Walmsley, I. A.

    2008-04-01

    It was ten years ago in Rochester, New York that the first SPIDER was built. This simple acronym belies the subtleties of its inner workings; Spectral Phase Interferometry for Direct Electric-field Reconstruction (the ``f'' in field conveniently missed the cut) is a device that measures ultrashort pulses, utilizing spectral shearing interferometry and directly recovering the spectral phase. The very first SPIDER apparatus occupied nearly half an optical table, used a scanning monochromator, and had no computerized inversion routine. In the intervening decade, SPIDER has grown up. It has found a strong foothold in ultrafast laboratories throughout the world. Multiple groups have found useful new applications with this vital measurement tool, while others have contributed to the improvement of SPIDER itself, reaching to ever shorter pulses, new wavelength regimes, and making devices more sensitive, robust, smaller and faster. It also adapts to a field of research that changes rapidly. It was first designed to track and quantify the remaining spectral phase in a pulse to perfect its compression. In ten years, with the advent of pulse shapers, the real benefits of field diagnostics are becoming apparent. We have shifted away from the race towards the shortest IR pulse to a wide use of complex shaped pulses in almost every spectral range from far IR to XUV. But the quest of the shortest pulse is not over and new compression techniques utilize really broad spectra that are highly structured. All these applications provide new challenges for characterization techniques.

  3. Constant potential pulse polarography

    USGS Publications Warehouse

    Christie, J.H.; Jackson, L.L.; Osteryoung, R.A.

    1976-01-01

    The new technique of constant potential pulse polarography, In which all pulses are to be the same potential, is presented theoretically and evaluated experimentally. The response obtained is in the form of a faradaic current wave superimposed on a constant capacitative component. Results obtained with a computer-controlled system exhibit a capillary response current similar to that observed In normal pulse polarography. Calibration curves for Pb obtained using a modified commercial pulse polarographic instrument are in good accord with theoretical predictions.

  4. Alternate drop pulse polarography

    USGS Publications Warehouse

    Christie, J.H.; Jackson, L.L.; Osteryoung, R.A.

    1976-01-01

    The new technique of alternate drop pulse polarography is presented. An experimental evaluation of alternate drop pulse polarography shows complete compensation of the capacitative background due to drop expansion. The capillary response phenomenon was studied in the absence of faradaic reaction and the capillary response current was found to depend on the pulse width to the -0.72 power. Increased signal-to-noise ratios were obtained using alternate drop pulse polarography at shorter drop times.

  5. Optically pulsed electron accelerator

    DOEpatents

    Fraser, John S.; Sheffield, Richard L.

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  6. Optically pulsed electron accelerator

    DOEpatents

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  7. Electrical pulse generator

    DOEpatents

    Norris, Neil J.

    1979-01-01

    A technique for generating high-voltage, wide dynamic range, shaped electrical pulses in the nanosecond range. Two transmission lines are coupled together by resistive elements distributed along the length of the lines. The conductance of each coupling resistive element as a function of its position along the line is selected to produce the desired pulse shape in the output line when an easily produced pulse, such as a step function pulse, is applied to the input line.

  8. Pulse-chase analysis for studying protein synthesis and maturation.

    PubMed

    Fritzsche, Susanne; Springer, Sebastian

    2014-11-03

    Pulse-chase analysis is a well-established and highly adaptable tool for studying the life cycle of endogenous proteins, including their synthesis, folding, subunit assembly, intracellular transport, post-translational processing, and degradation. This unit describes the performance and analysis of a radiolabel pulse-chase experiment for following the folding and cell surface trafficking of a trimeric murine MHC class I glycoprotein. In particular, the unit focuses on the precise timing of pulse-chase experiments to evaluate early/short-time events in protein maturation in both suspended and strictly adherent cell lines. The advantages and limitations of radiolabel pulse-chase experiments are discussed, and a comprehensive section for troubleshooting is provided. Further, ways to quantitatively represent pulse-chase results are described, and feasible interpretations on protein maturation are suggested. The protocols can be adapted to investigate a variety of proteins that may mature in very different ways.

  9. Analysis of Vacuous Pulse and Replete Pulse Using a Clip-type Pulsimeter Equipped with a Hall Sensor.

    PubMed

    Lee, Nam-Kyu; Rhee, Jin-Kyu; Lee, Sang-Suk

    2015-04-01

    A logistic regression equation for the vacuous pulse and the replete pulse was determined based on data obtained using a clip-type pulsimeter equipped with a Hall device that sensed the change in the magnetic field due to the minute movement of a radial artery. To evaluate the efficacy of the two different pulses from the deficiency and the excess syndrome groups, we performed a clinical trial, and we used a statistical regression analysis to process the clinical data from the 180 participants who were enrolled in this study. The ratio of the systolic peak's amplitude to its time in the pulse's waveform was found to be a major efficacy parameter for differentiating between the vacuous pulse and the replete pulse using an empirical equation that was deduced from the data using a statistical logistic regression method. This logistic regression equation can be applied to develop a novel algorithm for pulse measurements based on Oriental medical diagnoses.

  10. Hybrid chirped pulse amplification system

    DOEpatents

    Barty, Christopher P.; Jovanovic, Igor

    2005-03-29

    A hybrid chirped pulse amplification system wherein a short-pulse oscillator generates an oscillator pulse. The oscillator pulse is stretched to produce a stretched oscillator seed pulse. A pump laser generates a pump laser pulse. The stretched oscillator seed pulse and the pump laser pulse are directed into an optical parametric amplifier producing an optical parametric amplifier output amplified signal pulse and an optical parametric amplifier output unconverted pump pulse. The optical parametric amplifier output amplified signal pulse and the optical parametric amplifier output laser pulse are directed into a laser amplifier producing a laser amplifier output pulse. The laser amplifier output pulse is compressed to produce a recompressed hybrid chirped pulse amplification pulse.

  11. Stress pulse phenomena

    SciTech Connect

    McGlaun, M.

    1993-08-01

    This paper is an introductory discussion of stress pulse phenomena in simple solids and fluids. Stress pulse phenomena is a very rich and complex field that has been studied by many scientists and engineers. This paper describes the behavior of stress pulses in idealized materials. Inviscid fluids and simple solids are realistic enough to illustrate the basic behavior of stress pulses. Sections 2 through 8 deal with the behavior of pressure pulses. Pressure is best thought of as the average stress at a point. Section 9 deals with shear stresses which are most important in studying solids.

  12. Stability of a modified Peaceman-Rachford method for the paraxial Helmholtz equation on adaptive grids

    NASA Astrophysics Data System (ADS)

    Sheng, Qin; Sun, Hai-wei

    2016-11-01

    This study concerns the asymptotic stability of an eikonal, or ray, transformation based Peaceman-Rachford splitting method for solving the paraxial Helmholtz equation with high wave numbers. Arbitrary nonuniform grids are considered in transverse and beam propagation directions. The differential equation targeted has been used for modeling propagations of high intensity laser pulses over a long distance without diffractions. Self-focusing of high intensity beams may be balanced with the de-focusing effect of created ionized plasma channel in the situation, and applications of grid adaptations are frequently essential. It is shown rigorously that the fully discretized oscillation-free decomposition method on arbitrary adaptive grids is asymptotically stable with a stability index one. Simulation experiments are carried out to illustrate our concern and conclusions.

  13. Toothbrush Adaptations.

    ERIC Educational Resources Information Center

    Exceptional Parent, 1987

    1987-01-01

    Suggestions are presented for helping disabled individuals learn to use or adapt toothbrushes for proper dental care. A directory lists dental health instructional materials available from various organizations. (CB)

  14. PULSE DURATION LENGTHENER

    DOEpatents

    Aiken, W.R.

    1958-02-01

    This patent pertains to pulse modifying apparatus and, more particularly, describes a device to provide a rise time and time base expander for signal pulses having a very short duration. The basic element of the device is a vacuum tube comprising a charged particie beam, grid control means, an accelerating electrode, a drift tube, and a collector electrode. As the short duration input pulse modulates the particle beam through the grid control means, the voltage between the drift tube and accelerating electrode is caused to vary, whereby the output signal from the collector is a pulse having longer rise time, expanded duration and proportionate characteristics of the original pulse. The invention is particuiarly useful where subsequent pulse circultry does not have the frequency bandwidth to handle the short duration pulse without distorting it.

  15. ELECTRICAL PULSE COUNTER APPARATUS

    DOEpatents

    Kaufman, W.M.; Jeeves, T.A.

    1962-09-01

    A progressive electrical pulse counter circuit rs designed for the counting of a chain of input pulses. The circuit employs a series of direct connected bistable counting stages simultaneously pulsed by each input pulse and a delay means connected between each of the stages. Each bistable stage has two d-c operative states, which stage, when in its initial state, prevents the next succeeding stage from changing its condition when the latter stage is pulsed. Since the delay circuits between the stages prevents the immediate decay of the d-c state of each stage when the stages are pulsed, only one stage will change its state for each input pulse, thereby providing progressive stage-by-stage counting. (AEC)

  16. GPU simulation of nonlinear propagation of dual band ultrasound pulse complexes

    SciTech Connect

    Kvam, Johannes Angelsen, Bjørn A. J.; Elster, Anne C.

    2015-10-28

    In a new method of ultrasound imaging, called SURF imaging, dual band pulse complexes composed of overlapping low frequency (LF) and high frequency (HF) pulses are transmitted, where the frequency ratio LF:HF ∼ 1 : 20, and the relative bandwidth of both pulses are ∼ 50 − 70%. The LF pulse length is hence ∼ 20 times the HF pulse length. The LF pulse is used to nonlinearly manipulate the material elasticity observed by the co-propagating HF pulse. This produces nonlinear interaction effects that give more information on the propagation of the pulse complex. Due to the large difference in frequency and pulse length between the LF and the HF pulses, we have developed a dual level simulation where the LF pulse propagation is first simulated independent of the HF pulse, using a temporal sampling frequency matched to the LF pulse. A separate equation for the HF pulse is developed, where the the presimulated LF pulse modifies the propagation velocity. The equations are adapted to parallel processing in a GPU, where nonlinear simulations of a typical HF beam of 10 MHz down to 40 mm is done in ∼ 2 secs in a standard GPU. This simulation is hence very useful for studying the manipulation effect of the LF pulse on the HF pulse.

  17. Relation of pulse pressure and arterial stiffness to concentric left ventricular hypertrophy in young men (from the Bogalusa Heart Study).

    PubMed

    Toprak, Ahmet; Reddy, Jagadeesh; Chen, Wei; Srinivasan, Sathanur; Berenson, Gerald

    2009-04-01

    Differences in geometric adaptation of the left ventricle and associated cardiovascular risk may reflect the differential effects of classic risk factors and arterial stiffness on the left ventricle. In the present study, the influence of cardiovascular risk factors and arterial stiffness indexes on left ventricular (LV) geometry types were studied in a large community-based cohort of young adults. As part of the Bogalusa Heart Study, echocardiographic examinations of the heart were performed on 786 black and white adults (age range 24 to 43 years, average 36; 42% men, 70% white). Arterial stiffness indexes of the study cohort included aorta-femoral pulse wave velocity, carotid artery elastic modulus, and arterial compliance using tonometry. Pulse pressure in young adults with concentric LV hypertrophy (47 +/- 11 mm Hg) was significantly higher than in those with eccentric LV hypertrophy (40 +/- 8 mm Hg) and normal geometry (37 +/- 7 mm Hg). Multinomial logistic regression analysis showed that widened pulse pressure, the presence of diabetes mellitus, and increased body mass index were associated with concentric LV hypertrophy compared with normal geometry. Similarly, higher Peterson's and Young's elastic modulus of the carotid arteries and lower large- and small-artery compliance, in addition to increased body mass index, diabetes mellitus, and black race, were associated with concentric LV hypertrophy in young adults. In conclusion these data suggested that concentric LV hypertrophy was associated with widened pulse pressure, increased arterial stiffness, and decreased arterial compliance in young adults.

  18. PULSE RATE DIVIDER

    DOEpatents

    McDonald, H.C. Jr.

    1962-12-18

    A compact pulse-rate divider circuit affording low impedance output and high input pulse repetition rates is described. The circuit features a single secondary emission tube having a capacitor interposed between its dynode and its control grid. An output pulse is produced at the anode of the tube each time an incoming pulse at the control grid drives the tube above cutoff and the duration of each output pulse corresponds to the charging time of the capacitor. Pulses incoming during the time the grid bias established by the discharging capacitor is sufficiently negative that the pulses are unable to drive the tube above cutoff do not produce output pulses at the anode; these pulses are lost and a dividing action is thus produced by the circuit. The time constant of the discharge path may be vanied to vary in turn the division ratio of the circuit; the time constant of the charging circuit may be varied to vary the width of the output pulses. (AEC)

  19. Adaptive behaviour of silicon oxide memristive nanostructures

    NASA Astrophysics Data System (ADS)

    Korolev, D. S.; Mikhaylov, A. N.; Belov, A. I.; Sergeev, V. A.; Antonov, I. N.; Gorshkov, O. N.; Tetelbaum, D. I.

    2016-08-01

    The response to electrical pulses of various parameters has been studied for the CMOS-compatible memristive nanostructures on the basis of silicon oxide demonstrating reproducible resistive switching. It is established that an increase in the amplitude or width of a single programming pulse is followed by the gradual decrease in the device resistivity. By applying periodic pulse sequences of different polarity it is possible to obtain both lower and higher resistance states. This adaptive behavior is analogous to synaptic plasticity and considered as one of the main conditions for the application of memristive devices in neuromorphic systems and synaptic electronics.

  20. DIFFERENTIAL FAULT SENSING CIRCUIT

    DOEpatents

    Roberts, J.H.

    1961-09-01

    A differential fault sensing circuit is designed for detecting arcing in high-voltage vacuum tubes arranged in parallel. A circuit is provided which senses differences in voltages appearing between corresponding elements likely to fault. Sensitivity of the circuit is adjusted to some level above which arcing will cause detectable differences in voltage. For particular corresponding elements, a group of pulse transformers are connected in parallel with diodes connected across the secondaries thereof so that only voltage excursions are transmitted to a thyratron which is biased to the sensitivity level mentioned.

  1. Adaptive response modelling

    NASA Astrophysics Data System (ADS)

    Campa, Alessandro; Esposito, Giuseppe; Belli, Mauro

    Cellular response to radiation is often modified by a previous delivery of a small "priming" dose: a smaller amount of damage, defined by the end point being investigated, is observed, and for this reason the effect is called adaptive response. An improved understanding of this effect is essential (as much as for the case of the bystander effect) for a reliable radiation risk assessment when low dose irradiations are involved. Experiments on adaptive response have shown that there are a number of factors that strongly influence the occurrence (and the level) of the adaptation. In particular, priming doses and dose rates have to fall in defined ranges; the same is true for the time interval between the delivery of the small priming dose and the irradiation with the main, larger, dose (called in this case challenging dose). Different hypotheses can be formulated on the main mechanism(s) determining the adaptive response: an increased efficiency of DNA repair, an increased level of antioxidant enzymes, an alteration of cell cycle progression, a chromatin conformation change. An experimental clearcut evidence going definitely in the direction of one of these explanations is not yet available. Modelling can be done at different levels. Simple models, relating the amount of damage, through elementary differential equations, to the dose and dose rate experienced by the cell, are relatively easy to handle, and they can be modified to account for the priming irradiation. However, this can hardly be of decisive help in the explanation of the mechanisms, since each parameter of these models often incorporates in an effective way several cellular processes related to the response to radiation. In this presentation we show our attempts to describe adaptive response with models that explicitly contain, as a dynamical variable, the inducible adaptive agent. At a price of a more difficult treatment, this approach is probably more prone to give support to the experimental studies

  2. [Cellular adaptation and cancerogenesis].

    PubMed

    La Torre, F; Silpigni, A; Tomasello, R; Picone, G S; La Torre, I; Aragona, M

    1998-06-01

    The paper describes the main adaptive mechanisms involved in the carcinogenic process. As a result of the action of carcinogenic agents (physical, chemical, biological), and in relation to the functional status of the affected cells, a number of systems are triggered off: detoxification and conjugation systems, the metabolisation of the said agents, DNA repairing enzymes, increased shock proteins (HSP), the induction of clonal proliferation. All these systems are valuable to the survival of the body and the species and culminate in the apoptosis of damaged cells as the last attempt at adaptation of a social kind for the good of the body. When these compensation mechanisms prove ineffective, imprecise or are exceeded by cell adaptive capacity, the resulting structural and functional alterations trigger off (induction) a very long process which often lasts between one and two thirds of the body's life, in various stages, multistep and multifactorial: this neoplastic transformation leads to a purposeless, egoistic, anarchic proliferation of cells which wish to survive at all costs, even to the detriment of the body of which they form part. Following the exhaustion of cell adaptive defences, there is an accumulation of additional genetic alterations (promotion and progression), the cells become manifestly neoplastic and continue their egoistic adaptation, according to the laws of natural selection: the cells which survive are those which adapt best to the hostile environment of the host's body, which are unaffected by proliferation control mechanisms (contact inhibition, differentiation factors, apoptosis, etc.), which make the best of the growth factors present in their microenvironment, which accomplish the so-called decathlon of the metastatization process, namely acquiring new capacities which can overcome the basal membrane, invade tissues to which they are attracted and continue to proliferate. Manifestly neoplastic cells become not self at a later stage

  3. [INVITED] Control of femtosecond pulsed laser ablation and deposition by temporal pulse shaping

    NASA Astrophysics Data System (ADS)

    Garrelie, Florence; Bourquard, Florent; Loir, Anne--Sophie; Donnet, Christophe; Colombier, Jean-Philippe

    2016-04-01

    This study explores the effects of temporal laser pulse shaping on femtosecond pulsed laser deposition (PLD). The potential of laser pulses temporally tailored on ultrafast time scales is used to control the expansion and the excitation degree of ablation products including atomic species and nanoparticles. The ablation plume generated by temporally shaped femtosecond pulsed laser ablation of aluminum and graphite targets is studied by in situ optical diagnostic methods. Taking advantage of automated pulse shaping techniques, an adaptive procedure based on spectroscopic feedback regulates the irradiance for the enhancement of typical plasma features. Thin films elaborated by unshaped femtosecond laser pulses and by optimized sequence indicate that the nanoparticles generation efficiency is strongly influenced by the temporal shaping of the laser irradiation. The ablation processes leading either to the generation of the nanoparticles either to the formation of plasma can be favored by using a temporal shaping of the laser pulse. Insights are given on the possibility to control the quantity of the nanoparticles. The temporal laser pulse shaping is shown also to strongly modify the laser-induced plasma contents and kinetics for graphite ablation. Temporal pulse shaping proves its capability to reduce the number of slow radicals while increasing the proportion of monomers, with the addition of ionized species in front of the plume. This modification of the composition and kinetics of plumes in graphite ablation using temporal laser pulse shaping is discussed in terms of modification of the structural properties of deposited Diamond-Like Carbon films (DLC). This gives rise to a better understanding of the growth processes involved in femtosecond-PLD and picosecond-PLD of DLC suggesting the importance of neutral C atoms, which are responsible for the subplantation process.

  4. Pulse dynamics in an unstable medium

    SciTech Connect

    Balmforth, N.J.; Ierley, G.R.; Worthing, R.

    1995-05-01

    A study is presented of a one-dimensional, nonlinear partial differential equation that describes evolution of dispersive, long-wave instability. The solutions, under certain specific conditions, take the form of trains of well-separated pulses. The dynamics of such patterns of pulses is investigated using singular perturbation theory and with numerical simulation. These tools permit the formulation of a theory of pulse interaction, and enable the mapping out of the range of behavior in parameter space. There are regimes in which steady trains form; such states can be studied with the asymptotic, pulse-interaction theory. In other regimes, pulse trains are unstable to global, wave-like modes or its radiation. This can precipitate more violent phenomena involving pulse creation, or generate periodic states which may follow Shil`nikov`s route to temporal chaos. The asymptotic theory is generalized lo take some account of radiative dynamics. In the limit of small dispersion, steady trains largely cease to exist; the system follows various pathways to temporal complexity and typical-bifurcation sequences are sketched out. The investigation guides us to a critical appraisal of the asymptotic theory and uncovers the wealth of different types of behavior present in the system.

  5. Adaptive Development

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The goal of this research is to develop and demonstrate innovative adaptive seal technologies that can lead to dramatic improvements in engine performance, life, range, and emissions, and enhance operability for next generation gas turbine engines. This work is concentrated on the development of self-adaptive clearance control systems for gas turbine engines. Researchers have targeted the high-pressure turbine (HPT) blade tip seal location for following reasons: Current active clearance control (ACC) systems (e.g., thermal case-cooling schemes) cannot respond to blade tip clearance changes due to mechanical, thermal, and aerodynamic loads. As such they are prone to wear due to the required tight running clearances during operation. Blade tip seal wear (increased clearances) reduces engine efficiency, performance, and service life. Adaptive sealing technology research has inherent impact on all envisioned 21st century propulsion systems (e.g. distributed vectored, hybrid and electric drive propulsion concepts).

  6. PULSE AMPLITUDE ANALYZER

    DOEpatents

    Greenblatt, M.H.

    1958-03-25

    This patent pertains to pulse amplitude analyzers for sorting and counting a serles of pulses, and specifically discloses an analyzer which ls simple in construction and presents the puise height distribution visually on an oscilloscope screen. According to the invention, the pulses are applied to the vertical deflection plates of an oscilloscope and trigger the horizontal sweep. Each pulse starts at the same point on the screen and has a maximum amplitude substantially along the same vertical line. A mask is placed over the screen except for a slot running along the line where the maximum amplitudes of the pulses appear. After the slot has been scanned by a photocell in combination with a slotted rotating disk, the photocell signal is displayed on an auxiliary oscilloscope as vertical deflection along a horizontal time base to portray the pulse amplitude distribution.

  7. PULSE AMPLITUDE ANALYSERS

    DOEpatents

    Lewis, I.A.D.

    1956-05-15

    This patent pentains to an electrical pulse amplitude analyzer, capable of accepting input pulses having a separation between adjacent pulses in the order of one microsecond while providing a large number of channels of classification. In its broad aspect the described pulse amplitude analyzer utilizes a storage cathode ray tube und control circuitry whereby the amplitude of the analyzed pulses controls both the intensity and vertical defiection of the beam to charge particular spots in horizontal sectors of the tube face as the beam is moved horizontally across the tube face. As soon as the beam has swept the length of the tube the information stored therein is read out by scanning individually each horizontal sector corresponding to a certain range of pulse amplitudes and applying the output signal from each scan to separate indicating means.

  8. Adaptive management

    USGS Publications Warehouse

    Allen, Craig R.; Garmestani, Ahjond S.

    2015-01-01

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive management has explicit structure, including a careful elucidation of goals, identification of alternative management objectives and hypotheses of causation, and procedures for the collection of data followed by evaluation and reiteration. The process is iterative, and serves to reduce uncertainty, build knowledge and improve management over time in a goal-oriented and structured process.

  9. A robust method for pulse peak determination in a digital volume pulse waveform with a wandering baseline.

    PubMed

    Jang, Dae-Geun; Farooq, Umar; Park, Seung-Hun; Hahn, Minsoo

    2014-10-01

    This paper presents a robust method for pulse peak determination in a digital volume pulse (DVP) waveform with a wandering baseline. A proposed new method uses a modified morphological filter (MMF) to eliminate a wandering baseline signal of the DVP signal with minimum distortion and a slope sum function (SSF) with an adaptive thresholding scheme to detect pulse peaks from the baseline-removed DVP signal. Further in order to cope with over-detected and missed pulse peaks, knowledge based rules are applied as a postprocessor. The algorithm automatically adjusts detection parameters periodically to adapt to varying beat morphologies and fluctuations. Compared with conventional methods (highpass filtering, linear interpolation, cubic spline interpolation, and wavelet adaptive filtering), our method performs better in terms of the signal-to-error ratio, the computational burden (0.125 seconds for one minute of DVP signal analysis with the Intel Core 2 Quad processor @ 2.40 GHz PC), the true detection rate (97.32% with an acceptance level of 4 ms ) as well as the normalized error rate (0.18%). In addition, the proposed method can detect true positions of pulse peaks more accurately and becomes very useful for pulse transit time (PTT) and pulse rate variability (PRV) analyses. PMID:25388880

  10. PulseSoar

    SciTech Connect

    Carter, P.; Peglow, S.

    1992-07-21

    This paper is an introduction to the PulseSoar concept. PulseSoar is a hypervelocity airplane that uses existing airport facilities and current technologies to fly at the very edge of space. It will be shown that PulseSoar can fly between any two points on the globe in less than two hours with fuel efficiency exceeding current state of the art commercial airliners. In addition, it will be shown that PulseSoar avoids environmental issues concerning the ozone layer and sonic booms because of its unique flight profile. All of this can be achieved with current technology. PulseSoar does not require the development of enabling technology. It is a concept which can be demonstrated today. The importance of this idea goes beyond the technical significance`s of PulseSoar in terms of feasibility and performance. PulseSoar could provide a crucial economic advantage to America`s largest export market: commercial aircraft. PulseSoar is a breakthrough concept for addressing the emerging markets of long range and high speed aircraft. Application of PulseSoar to commercial transport could provide the US Aerospace industry a substantial lead in offering high speed/long range aircraft to the world`s airlines. The rapid emergence of a US developed high speed aircraft could also be important to our competitiveness in the Pacific Rim and South American economies. A quick and inexpensive demonstration vehicle is proposed to bang the concept to reality within two years. This discussion will address all the major technical subjects encompassed by PulseSoar and identifies several near-term, and low risk, applications which may be further explored with the initial demonstration vehicle. What is PulseSoar? PulseSoar could enable high speed, high altitude and long range flight without many of the difficulties encountered by traditional hypersonic vehicles.

  11. PULSED INDICATOR CIRCUIT

    DOEpatents

    Linlor, W.I.; Kerns, Q.A.

    1960-11-15

    A system is given for detecting incremental changes in a transducer impedance terminating a transmission line. Principal novelty resides in the transducer impedance terminating the line in a mismatch and a pulse generator being provided to apply discrete pulses to the input end of the line. The amplitudes of the pulses reflected to the input end of the line from the mismatched transducer impedance are then observed as a very accurate measure of the instantaneous value of the latter.

  12. High voltage pulse conditioning

    DOEpatents

    Springfield, Ray M.; Wheat, Jr., Robert M.

    1990-01-01

    Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

  13. Femtosecond polarization pulse shaping.

    PubMed

    Brixner, T; Gerber, G

    2001-04-15

    We report computer-controlled femtosecond polarization pulse shaping where intensity, momentary frequency, and light polarization are varied as functions of time. For the first time to our knowledge, a pulse shaper is used to modulate the degree of ellipticity as well as the orientation of the elliptical principal axes within a single laser pulse by use of a 256-pixel two-layer liquid-crystal display inside a zero-dispersion compressor. Interferometric stability of the setup is not required. Complete pulse characterization is achieved by dual-channel spectral interferometry. This technology has a large range of applications, especially in the field of quantum control.

  14. Femtosecond polarization pulse shaping.

    PubMed

    Brixner, T; Gerber, G

    2001-04-15

    We report computer-controlled femtosecond polarization pulse shaping where intensity, momentary frequency, and light polarization are varied as functions of time. For the first time to our knowledge, a pulse shaper is used to modulate the degree of ellipticity as well as the orientation of the elliptical principal axes within a single laser pulse by use of a 256-pixel two-layer liquid-crystal display inside a zero-dispersion compressor. Interferometric stability of the setup is not required. Complete pulse characterization is achieved by dual-channel spectral interferometry. This technology has a large range of applications, especially in the field of quantum control. PMID:18040384

  15. Adaptive Thresholds

    SciTech Connect

    Bremer, P. -T.

    2014-08-26

    ADAPT is a topological analysis code that allow to compute local threshold, in particular relevance based thresholds for features defined in scalar fields. The initial target application is vortex detection but the software is more generally applicable to all threshold based feature definitions.

  16. Opportunities in pulse combustion

    SciTech Connect

    Brenchley, D.L.; Bomelburg, H.J.

    1985-10-01

    In most pulse combustors, the combustion occurs near the closed end of a tube where inlet valves operate in phase with the pressure amplitude variations. Thus, within the combustion zone, both the temperature and the pressure oscillate around a mean value. However, the development of practical applications of pulse combustion has been hampered because effective design requires the right combination of the combustor's dimensions, valve characteristics, fuel/oxidizer combination, and flow pattern. Pulse combustion has several additional advantages for energy conversion efficiency, including high combustion and thermal efficiency, high combustion intensity, and high convective heat transfer rates. Also, pulse combustion can be self-aspirating, generating a pressure boost without using a blower. This allows the use of a compact heat exchanger that may include a condensing section and may obviate the need for a chimney. In the last decade, these features have revived interest in pulse combustion research and development, which has resulted in the development of a pulse combustion air heater by Lennox, and a pulse combustion hydronic unit by Hydrotherm, Inc. To appraise this potential for energy savings, a systematic study was conducted of the many past and present attempts to use pulse combustion for practical purposes. The authors recommended areas where pulse combustion technology could possibly be applied in the future and identified areas in which additional R and D would be necessary. Many of the results of the study project derived from a special workshop on pulse combustion. This document highlights the main points of the study report, with particular emphasis on pulse combustion application in chemical engineering.

  17. PULSE HEIGHT ANALYZER

    DOEpatents

    Johnstone, C.W.

    1958-01-21

    An anticoincidence device is described for a pair of adjacent channels of a multi-channel pulse height analyzer for preventing the lower channel from generating a count pulse in response to an input pulse when the input pulse has sufficient magnitude to reach the upper level channel. The anticoincidence circuit comprises a window amplifier, upper and lower level discriminators, and a biased-off amplifier. The output of the window amplifier is coupled to the inputs of the discriminators, the output of the upper level discriminator is connected to the resistance end of a series R-C network, the output of the lower level discriminator is coupled to the capacitance end of the R-C network, and the grid of the biased-off amplifier is coupled to the junction of the R-C network. In operation each discriminator produces a negative pulse output when the input pulse traverses its voltage setting. As a result of the connections to the R-C network, a trigger pulse will be sent to the biased-off amplifier when the incoming pulse level is sufficient to trigger only the lower level discriminator.

  18. Pulsed Fission Propulsion Concept

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the 1960's U.S. Government laboratories, under Project Orion, investigated a pulsed nuclear fission propulsion system. Small nuclear pulse units would be sequentially discharged from the aft end of the vehicle. A blast shield and shock absorber system would protect the crew and convert the shock loads into a continuous propusive force.

  19. Pulsed Fission Propulsion Concept

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the 1960's U.S. Government laboratories, under Project Orion, investigated a pulsed nuclear fission propulsion system. Small nuclear pulse units would be sequentially discharged from the aft end of the vehicle. A blast shield and shock absorber system would protect the crew and convert the shock loads into a continuous propulsive force.

  20. PULSE AMPLITUDE DISTRIBUTION RECORDER

    DOEpatents

    Cowper, G.

    1958-08-12

    A device is described for automatica1ly recording pulse annplitude distribution received from a counter. The novelty of the device consists of the over-all arrangement of conventional circuit elements to provide an easy to read permanent record of the pulse amplitude distribution during a certain time period. In the device a pulse analyzer separates the pulses according to annplitude into several channels. A scaler in each channel counts the pulses and operates a pen marker positioned over a drivable recorder sheet. Since the scalers in each channel have the sanne capacity, the control circuitry permits counting of the incoming pulses until one scaler reaches capacity, whereupon the input is removed and an internal oscillator supplies the necessary pulses to fill up the other scalers. Movement of the chart sheet is initiated wben the first scaler reaches capacity to thereby give a series of marks at spacings proportional to the time required to fill the remaining scalers, and accessory equipment marks calibration points on the recorder sheet to facilitate direct reading of the number of external pulses supplied to each scaler.

  1. Sources of pulsed radiation

    SciTech Connect

    Sauer, M.C. Jr.

    1981-01-01

    Characteristics of various sources of pulsed radiation are examined from the viewpoint of their importance to the radiation chemist, and some examples of uses of such sources are mentioned. A summary is given of the application of methods of physical dosimetry to pulsed sources, and the calibration of convenient chemical dosimeters by physical dosimetry is outlined. 7 figures, 1 table.

  2. Pulsed Laser Tissue Interaction

    NASA Astrophysics Data System (ADS)

    Walsh, Joseph T.; van Leeuwen, Ton G.; Jansen, E. Duco; Motamedi, Massoud; Welch, Ashley J.

    Pulsed lasers, by virtue of their ability to deliver energy in a spatially and temporally confined fashion, are able to micromachine biological tissues. The clinical success of pulsed laser treatment, however, is often limited by the extent of damage that is caused to the tissue in the vicinity of the ablation crater. In general, pulsed ablation is a trade off between thermal damage to surrounding tissue, caused by relatively long pulses (>100 ms), and mechanical damage to surrounding tissue, caused by relatively short pulses (<1 ms). To identify the origin of pulsed laser induced damage, the possible laser tissue interactions and ablation are discussed here and in Chapter 14. The purpose of this chapter is to provide the reader with a condensed overview of the parameters that must be considered in the process of pulsed laser ablation of soft tissue. In this chapter, pulsed infrared ablation of biological soft tissue is used as a paradigm to illustrate the concepts and design considerations. Generally speaking, the absorption of laser light may lead to photothermal, photomechanical or photochemical interaction with the irradiated tissue [1-5]. The vast majority of therapeutic laser-tissue interactions is based on photothermal interactions where laser energy is converted into heat. Subsequent to thermalization of the absorbed optical energy, heat transfer mechanisms, in particular conduction allow thermal diffusion from high temperature areas to surrounding regions. When laser penetration depth is less than the laser spot radius, the thermal diffusion time, τ th, can be defined as:

  3. Extrusion cooking: Legume pulses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extrusion is used commercially to produce high value breakfast and snack foods based on cereals such as wheat or corn. However, this processing method is not being commercially used for legume pulses seeds due to the perception that they do not expand well in extrusion. Extrusion cooking of pulses (...

  4. Composite Pulse Tube

    NASA Technical Reports Server (NTRS)

    Martin, Jerry L.; Cloyd, Jason H.

    2007-01-01

    A modification of the design of the pulse tube in a pulse-tube cryocooler reduces axial thermal conductance while preserving radial thermal conductance. It is desirable to minimize axial thermal conductance in the pulse-tube wall to minimize leakage of heat between the warm and cold ends of the pulse tube. At the same time, it is desirable to maximize radial thermal conductance at the cold end of the pulse tube to ensure adequate thermal contact between (1) a heat exchanger in the form of a stack of copper screens inside the pulse tube at the cold end and (2) the remainder of the cold tip, which is the object to which the heat load is applied and from which heat must be removed. The modified design yields a low-heat-leak pulse tube that can be easily integrated with a cold tip. A typical pulse tube of prior design is either a thin-walled metal tube or a metal tube with a nonmetallic lining. It is desirable that the outer surface of a pulse tube be cylindrical (in contradistinction to tapered) to simplify the design of a regenerator that is also part of the cryocooler. Under some conditions, it is desirable to taper the inner surface of the pulse tube to reduce acoustic streaming. The combination of a cylindrical outer surface and a tapered inner surface can lead to unacceptably large axial conduction if the pulse tube is made entirely of metal. Making the pulse-tube wall of a nonmetallic, lowthermal- conductivity material would not solve the problem because the wall would not afford the needed thermal contact for the stack of screens in the cold end. The modified design calls for fabricating the pulse tube in two parts: a longer, nonmetallic part that is tapered on the inside and cylindrical on the outside and a shorter, metallic part that is cylindrical on both the inside and the outside. The nonmetallic part can be made from G-10 fiberglass-reinforced epoxy or other low-thermal-conductivity, cryogenically compatible material. The metallic part must have high

  5. Pulsed electron beam precharger

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1990-01-01

    Florida State University is investigating the concept of pulsed electron beams for fly ash precipitation. This report describes the results and data on three of the subtasks of this project and preliminary work only on the remaining five subtasks. Described are the modification of precharger for pulsed and DC energization of anode; installation of the Q/A measurement system; and modification and installation of pulsed power supply to provide both pulsed and DC energization of the anode. The other tasks include: measurement of the removal efficiency for monodisperse simulated fly ash particles; measurement of particle charge; optimization of pulse energization schedule for maximum removal efficiency; practical assessment of results; and measurement of the removal efficiency for polydisperse test particles. 15 figs., 1 tab. (CK)

  6. Pulsed hall thruster system

    NASA Technical Reports Server (NTRS)

    Hruby, Vladimir J. (Inventor); Pote, Bruce M. (Inventor); Gamero-Castano, Manuel (Inventor)

    2004-01-01

    A pulsed Hall thruster system includes a Hall thruster having an electron source, a magnetic circuit, and a discharge chamber; a power processing unit for firing the Hall thruster to generate a discharge; a propellant storage and delivery system for providing propellant to the discharge chamber and a control unit for defining a pulse duration .tau.<0.1d.sup.3.rho./m, where d is the characteristic size of the thruster, .rho. is the propellant density at standard conditions, and m is the propellant mass flow rate for operating either the power processing unit to provide to the Hall thruster a power pulse of a pre-selected duration, .tau., or operating the propellant storage and delivery system to provide a propellant flow pulse of duration, .tau., or providing both as pulses, synchronized to arrive coincidentally at the discharge chamber to enable the Hall thruster to produce a discreet output impulse.

  7. Characterization of partially coherent ultrashort XUV pulses

    NASA Astrophysics Data System (ADS)

    Bourassin-Bouchet, Charles; Couprie, Marie-Emmanuelle

    2015-05-01

    Modern ultrafast metrology relies on the postulate that the pulse to be measured is fully coherent, i.e. that it can be completely described by its spectrum and spectral phase. However, synthesizing fully coherent pulses is not always possible in practice, especially in the domain of emerging ultrashort X-ray sources where temporal metrology is strongly needed. As an example, the lack of longitudinal coherence, that is shot-to-shot fluctuations, of Free-Electron Lasers (FEL) has prevented so far their full amplitude and phase temporal characterization. To sort out this issue, we have adapted Frequency-Resolved Optical Gating (FROG), the first and one of the most widespread techniques for pulse characterization, to enable the measurement of partially coherent XUV pulses even down to the attosecond timescale. Especially, this technique allows one to overcome the sources of decoherence that normally prevent a pulse measurement, such as the spectrometer resolution or the presence of XUV/laser arrival time jitter.

  8. Differentiated Staffing.

    ERIC Educational Resources Information Center

    Geisinger, Robert W.; And Others

    This report describes school operation changes in scheduling, curriculum, decisionmaking powers, and individualization of instruction that are concurrent with the adoption of differentiated staffing. The author defines differentiated staffing, explains where and at what levels it has been utilized, provides descriptions of results achieved, gives…

  9. Differential games.

    NASA Technical Reports Server (NTRS)

    Varaiya, P. P.

    1972-01-01

    General discussion of the theory of differential games with two players and zero sum. Games starting at a fixed initial state and ending at a fixed final time are analyzed. Strategies for the games are defined. The existence of saddle values and saddle points is considered. A stochastic version of a differential game is used to examine the synthesis problem.

  10. Connector adapter

    NASA Technical Reports Server (NTRS)

    Hacker, Scott C. (Inventor); Dean, Richard J. (Inventor); Burge, Scott W. (Inventor); Dartez, Toby W. (Inventor)

    2007-01-01

    An adapter for installing a connector to a terminal post, wherein the connector is attached to a cable, is presented. In an embodiment, the adapter is comprised of an elongated collet member having a longitudinal axis comprised of a first collet member end, a second collet member end, an outer collet member surface, and an inner collet member surface. The inner collet member surface at the first collet member end is used to engage the connector. The outer collet member surface at the first collet member end is tapered for a predetermined first length at a predetermined taper angle. The collet includes a longitudinal slot that extends along the longitudinal axis initiating at the first collet member end for a predetermined second length. The first collet member end is formed of a predetermined number of sections segregated by a predetermined number of channels and the longitudinal slot.

  11. Adaptive VFH

    NASA Astrophysics Data System (ADS)

    Odriozola, Iñigo; Lazkano, Elena; Sierra, Basi

    2011-10-01

    This paper investigates the improvement of the Vector Field Histogram (VFH) local planning algorithm for mobile robot systems. The Adaptive Vector Field Histogram (AVFH) algorithm has been developed to improve the effectiveness of the traditional VFH path planning algorithm overcoming the side effects of using static parameters. This new algorithm permits the adaptation of planning parameters for the different type of areas in an environment. Genetic Algorithms are used to fit the best VFH parameters to each type of sector and, afterwards, every section in the map is labelled with the sector-type which best represents it. The Player/Stage simulation platform has been chosen for making all sort of tests and to prove the new algorithm's adequateness. Even though there is still much work to be carried out, the developed algorithm showed good navigation properties and turned out to be softer and more effective than the traditional VFH algorithm.

  12. Localized wave pulse experiments

    SciTech Connect

    Chambers, D L; Henderson, T L; Krueger, K L; Lewis, D K; Zilkowski, R N

    1999-06-01

    The Localized Wave project of the Strategic System Support Program has recently finished an experiment in cooperation with the Advanced SONAR group of the Applied Research Laboratory of the University of Texas at Austin. The purpose of the experiment was three-fold. They wanted to see if (1) the LW pulse could propagate over significant distances, to see if (2) a new type of array and drive system specifically designed for the pulse would increase efficiency over single frequency tone bursts, and to see if (3) the complexity of our 24 channel drivers resulted in better efficiency than a single equivalent pulse driving a piston. In the experiment, several LW pulses were launched from the Lake Travis facility and propagated over distances of either 100 feet or 600 feet, through a thermocline for the 600 foot measurements. The results show conclusively that the Localized Wave will propagate past the near field distance. The LW pulses resulted in extremely broad frequency band width pulses with narrow spatial beam patterns and unmeasurable side lobes. Their array gain was better than most tone bursts and further, were better than their equivalent piston pulses. This marks the first test of several Low Diffraction beams against their equivalent piston pulses, as well as the first propagation of LW pulses over appreciable distances. The LW pulse is now proven a useful tool in open water, rather than a laboratory curiosity. The experimental system and array were built by ARL, and the experiments were conducted by ARL staff on their standard test range. The 600 feet measurements were made at the farthest extent of that range.

  13. Adaptive sampler

    DOEpatents

    Watson, B.L.; Aeby, I.

    1980-08-26

    An adaptive data compression device for compressing data is described. The device has a frequency content, including a plurality of digital filters for analyzing the content of the data over a plurality of frequency regions, a memory, and a control logic circuit for generating a variable rate memory clock corresponding to the analyzed frequency content of the data in the frequency region and for clocking the data into the memory in response to the variable rate memory clock.

  14. Adaptive sampler

    DOEpatents

    Watson, Bobby L.; Aeby, Ian

    1982-01-01

    An adaptive data compression device for compressing data having variable frequency content, including a plurality of digital filters for analyzing the content of the data over a plurality of frequency regions, a memory, and a control logic circuit for generating a variable rate memory clock corresponding to the analyzed frequency content of the data in the frequency region and for clocking the data into the memory in response to the variable rate memory clock.

  15. Adaptive antennas

    NASA Astrophysics Data System (ADS)

    Barton, P.

    1987-04-01

    The basic principles of adaptive antennas are outlined in terms of the Wiener-Hopf expression for maximizing signal to noise ratio in an arbitrary noise environment; the analogy with generalized matched filter theory provides a useful aid to understanding. For many applications, there is insufficient information to achieve the above solution and thus non-optimum constrained null steering algorithms are also described, together with a summary of methods for preventing wanted signals being nulled by the adaptive system. The three generic approaches to adaptive weight control are discussed; correlation steepest descent, weight perturbation and direct solutions based on sample matrix conversion. The tradeoffs between hardware complexity and performance in terms of null depth and convergence rate are outlined. The sidelobe cancellor technique is described. Performance variation with jammer power and angular distribution is summarized and the key performance limitations identified. The configuration and performance characteristics of both multiple beam and phase scan array antennas are covered, with a brief discussion of performance factors.

  16. Differential phase shift quantum key distribution.

    PubMed

    Inoue, Kyo; Waks, Edo; Yamamoto, Yoshihisa

    2002-07-15

    A novel quantum cryptography scheme is proposed, in which a single photon is prepared in a linear superposition state of three basis kets. A photon split to three pulses is sent from Alice to Bob, where the phase difference between sequential two pulses carries bit information. Bob measures the phase difference by passive differential phase detection. This scheme is suitable for fiber transmission systems and offers a key creation efficiency higher than conventional fiber-based BB84. PMID:12144419

  17. Adaptive Combining of Coherently Detected PPM Signals in the Presence of Atmospheric Turbulence

    NASA Technical Reports Server (NTRS)

    Fernandez, Michela Munoz; Vilnrotter, Victor A.

    2004-01-01

    Adaptive combining of experimentally obtained heterodyned pulse position modulated (PPM) signals with pulse-to-pulse coherence, in the presence of simulated spatial distortions resembling atmospheric turbulence, is demonstrated. The adaptively combined PPM signals are phased up via an LMS algorithm suitably optimized to operate with PPM in the presence of additive shot-noise. A convergence study of the algorithm is presented, and results with both computer simulated and experimentally obtained PPM signals are presented and analyzed.

  18. Modeling of near infrared pulsed laser sintering of metallic powders

    NASA Astrophysics Data System (ADS)

    Fischer, Pascal; Romano, Valerio; Weber, Heinz P.; Karapatis, N. P.; André, C.; Glardon, R.

    2003-11-01

    Using pulsed near infrared laser radiation for selective laser sintering bears several advantages compared to cw sintering such as low requried average power, less residual heat and improved lateral precision. By adapting the pulse length (and thus the heat diffusion length during the pulse) to the grain size of the used metal powder, the laser pulse energy can mainly by deposited in the skin of the powder particles where heating and melting is obtained, whereas the centers of the grains remain at much lower temperature and act as heat sinks after consolidation. The model described here was numerically implemented and experimentally tested with a pulsed Nd:YAG laser on titanium powder. The results of the model predictions and the performed experiments are in good agreement.

  19. Preference pulses without reinforcers.

    PubMed

    McLean, Anthony P; Grace, Randolph C; Pitts, Raymond C; Hughes, Christine E

    2014-05-01

    Preference pulses are thought to represent strong, short-term effects of reinforcers on preference in concurrent schedules. However, the general shape of preference pulses is substantially determined by the distributions of responses-per-visit (visit lengths) for the two choice alternatives. In several series of simulations, we varied the means and standard deviations of distributions describing visits to two concurrently available response alternatives, arranged "reinforcers" according to concurrent variable-interval schedules, and found a range of different preference pulses. Because characteristics of these distributions describe global aspects of behavior, and the simulations assumed no local effects of reinforcement, these preference pulses derive from the visit structure alone. This strongly questions whether preference pulses should continue to be interpreted as representing local effects of reinforcement. We suggest an alternative approach whereby local effects are assessed by subtracting the artifactual part, which derives from visit structure, from the observed preference pulses. This yields "residual" preference pulses. We illustrate this method in application to published data from mixed dependent concurrent schedules, revealing evidence that the delivery of reinforcers had modest lengthening effects on the duration of the current visit, a conclusion that is quantitatively consistent with early research on short-term effects of reinforcement.

  20. Differential effects of the histamine H3 receptor agonist methimepip on dentate granule cell excitability, paired-pulse plasticity and long-term potentiation in prenatal alcohol-exposed rats

    PubMed Central

    Varaschin, Rafael K.; Rosenberg, Martina J.; Hamilton, Derek A.; Savage, Daniel D.

    2016-01-01

    We previously reported that prenatal alcohol-induced deficits in dentate gyrus (DG) long-term potentiation (LTP) are ameliorated by the histamine H3 receptor inverse agonist ABT-239. ABT-239 did not enhance LTP in control rats, suggesting a heightened H3 receptor-mediated inhibition of glutamate release in prenatal alcohol-exposed (PAE) offspring. As the modulation of glutamate release is one important facet of LTP, we examined the effect of methimepip, a histamine H3 receptor agonist, on DG granule cell excitability, glutamate release and LTP in control and PAE rats. Long-Evans rat dams voluntarily consumed either a 0% or 5% ethanol solution four hours daily throughout gestation. Male adult offspring were anesthetized with urethane and electrodes implanted into the entorhinal cortex and DG. PAE reduced coupling of excitatory post-synaptic field potentials to population spikes, an effect mimicked in control rats treated with 1 mg/kg methimepip. Methimepip decreased release probability in controls but not in PAE offspring. GABAergic feedback inhibition of granule cell responsiveness was not affected by either PAE or methimepip. PAE reduced LTP in the DG, another effect mimicked in methimepip-treated control rats. Again, methimepip did not exacerbate the PAE-induced LTP deficit. Thus, while methimepip treatment of control rats mimicked some baseline and activity-dependent deficits observed in saline-treated PAE offspring, methimepip treatment of PAE rats did not exacerbate these deficits. Whether the absence of an added methimepip effect in PAE offspring is a consequence of a “floor effect” for the responses measured or is due to differential drug dose responsiveness will require further investigation. Further, more detailed studies of H3 receptor-mediated responses in vitro may provide clearer insights into the role of the H3 receptor regulation of excitatory transmission at the perforant path - DG synapse in PAE rats. PMID:24818819

  1. RF pulsed heating

    NASA Astrophysics Data System (ADS)

    Pritzkau, David Peace

    RF pulsed heating is a process by which a metal is heated from magnetic fields on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic field on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE011 mode at a resonant frequency of 11.424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1.5 μs pulses. The test pieces of the cavity are designed to be removable to allow testing of different materials with different surface preparations. A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE012 mode to steady-state in the cavity at 18 GHz and measuring the change in reflected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 × 106 pulses. The second run was executed at a calculated temperature rise of 82 K for 86 × 106 pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  2. Dynamic pulse difference circuit

    DOEpatents

    Erickson, Gerald L.

    1978-01-01

    A digital electronic circuit of especial use for subtracting background activity pulses in gamma spectrometry comprises an up-down counter connected to count up with signal-channel pulses and to count down with background-channel pulses. A detector responsive to the count position of the up-down counter provides a signal when the up-down counter has completed one scaling sequence cycle of counts in the up direction. In an alternate embodiment, a detector responsive to the count position of the up-down counter provides a signal upon overflow of the counter.

  3. SHORT PULSE STRETCHER

    DOEpatents

    Branum, D.R.; Cummins, W.F.

    1962-12-01

    >A short pulse stretching circuit capable of stretching a short puise to enable it to be displayed on a relatively slow sweeping oscilloscope is described. Moreover, the duration of the pulse is increased by charging a capacitor through a diode and thereafter discharging the capacitor at such time as is desired. In the circuit the trigger pulse alone passes through a delay line, whereas the main signal passes through the diode only, and results in over-all circuit losses which are proportional to the low losses of the diode only. (AEC)

  4. A pulsed CO2 Doppler lidar for boundary layer monitoring

    NASA Technical Reports Server (NTRS)

    Pearson, Guy N.

    1992-01-01

    A monostatic, master oscillator power amplifier (MOPA), CO2 pulsed Doppler lidar was constructed and tested. The system is compact (120 x 60 cm), operates at high pulse repetition rates (greater than 1 kHz) and is intended for simultaneous Doppler/Differential Absorption Lidar (DIAL) monitoring of the planetary boundary layer. Details of the system design, hard target calibrations, and aerosol returns are presented.

  5. High pulse repetition frequency, multiple wavelength, pulsed CO2 lidar system for atmospheric transmission and target reflectance measurements

    NASA Astrophysics Data System (ADS)

    Ben-David, Avishai; Emery, Silvio L.; Gotoff, Steven W.; D'Amico, Francis M.

    1992-07-01

    A multiple wavelength, pulsed CO2 lidar system operating at a pulse repetition frequency of 200 Hz and permitting the random selection of CO2 laser wavelengths for each laser pulse is presented. This system was employed to measure target reflectance and atmospheric transmission by using laser pulse bursts consisting of groups with as many as 16 different wavelengths at a repetition rate of 12 Hz. The wavelength tuning mechanism of the transversely excited atmospheric laser consists of a stationary grating and a flat mirror controlled by a galvanometer. Multiple wavelength, differential absorption lidar (DIAL) measurements reduce the effects of differential target reflectance and molecular absorption interference. Examples of multiwavelength DIAL detection for ammonia and water vapor show the dynamic interaction between these two trace gases. Target reflectance measurements for maple trees in winter and autumn are presented.

  6. High pulse repetition frequency, multiple wavelength, pulsed CO(2) lidar system for atmospheric transmission and target reflectance measurements.

    PubMed

    Ben-David, A; Emery, S L; Gotoff, S W; D'Amico, F M

    1992-07-20

    A multiple wavelength, pulsed CO(2) lidar system operating at a pulse repetition frequency of 200 Hz and permitting the random selection of CO(2) laser wavelengths for each laser pulse is presented. This system was employed to measure target reflectance and atmospheric transmission by using laser pulse bursts consisting of groups with as many as 16 different wavelengths at a repetition rate of 12 Hz. The wavelength tuning mechanism of the transversely excited atmospheric laser consists of a stationary grating and a flat mirror controlled by a galvanometer. Multiple wavelength, differential absorption lidar (DIAL) measurements reduce the effects of differential target reflectance and molecular absorption interference. Examples of multiwavelength DIAL detection for ammonia and water vapor show the dynamic interaction between these two trace gases. Target reflectance measurements for maple trees in winter and autumn are presented. PMID:20725406

  7. Parallel Algorithm Solves Coupled Differential Equations

    NASA Technical Reports Server (NTRS)

    Hayashi, A.

    1987-01-01

    Numerical methods adapted to concurrent processing. Algorithm solves set of coupled partial differential equations by numerical integration. Adapted to run on hypercube computer, algorithm separates problem into smaller problems solved concurrently. Increase in computing speed with concurrent processing over that achievable with conventional sequential processing appreciable, especially for large problems.

  8. A PC-controlled voltage pulse generator for electroanalytical applications

    NASA Astrophysics Data System (ADS)

    Heredia-López, Francisco J.; Góngora-Alfaro, José L.; Alvarez-Cervera, Fernando J.; Bata-García, José Luis

    1997-04-01

    We present the design of a voltage pulse generator controlled by an IBM or compatible AT Personal Computer (PC) capable of synthesizing some of the voltage pulse wave forms commonly used in electrochemical studies. The included signals are: differential pulse voltametry, differential normal pulse voltametry, and differential pulse amperometry. Additionally, a triangular wave form and a constant-voltage signal, used in the pretreatment of carbon fiber microelectrodes for neurochemical analysis, are also available. Operating the generator imposes a minimum of restrictions on the specification of the duration, amplitude, and type of wave shapes. Low-cost PC-based design allows for compatibility, portability, and versatility. The operating ranges of the wave form parameters for the three voltametric signals are: initial voltage, -0.9-+0.9 V; step amplitude, 0.1-900 mV; period, 6 ms-60 s; measuring pulse amplitude, 0.1-900 mV; measuring pulse duration, 2 ms-20 s; prepulse duration, 2 ms-20 s. In the electrode pretreatment mode, the operating ranges are: amplitude, 0-±5 V; duration, unlimited; frequency, 15-240 Hz. The generator uses its own time base for the generation of all signals, thereby rendering it independent of processor clock speed or power-line frequency. The results of the experimental evaluation indicate that the system is accurate within ±10% of the expected values, taking into account the errors associated with the signal synthesis and the digitizing process. The maximum achievable scan rate is 500 V/s, and the highest frequency for the triangular wave form is 240 Hz. Therefore, the pulse generator could be used for fast cyclic voltametry (FCV). FCV and other wave forms could be added through software modules, without any hardware changes. We conclude that the PC-based electrochemistry pulse generator represents an economical and flexible alternative for electroanalytical applications.

  9. DIFFERENTIAL ANALYZER

    DOEpatents

    Sorensen, E.G.; Gordon, C.M.

    1959-02-10

    Improvements in analog eomputing machines of the class capable of evaluating differential equations, commonly termed differential analyzers, are described. In general form, the analyzer embodies a plurality of basic computer mechanisms for performing integration, multiplication, and addition, and means for directing the result of any one operation to another computer mechanism performing a further operation. In the device, numerical quantities are represented by the rotation of shafts, or the electrical equivalent of shafts.

  10. Sexual differentiation.

    PubMed

    Sinisi, A A; Pasquali, D; Notaro, A; Bellastella, A

    2003-01-01

    In humans, like as in other mammals, the gonads, the internal genital ducts, and the external genital structures all develop from bipotential embryologic tissues. Male or female phenotype develops through a cascade of processes which initiate with sex determination and follow with sex differentiation. The karyotype (46, XY or 46, XX) of the embryo (genetic sex) determines whether primordial gonad differentiates into a testis or an ovary, respectively (gonadal differentiation). A Y-related gene, SRY, acts as a switch signal for testis differentiation. Testis development process involves several steps controlled by other non-OY-linked genes, such as Wilms tumor gene 1 (WT1), EMX2, LIM1, steroidogenic factor 1(SF-1), SRY box-related gene 9 (SOX9). Since other genes, such as Wnt-4 and DAX-1, are necessary for the initiation of female pathway in sex determination, female development cannot be considered a default process. Hormonal production of differentiated gonads is relevant for differentiation of the internal and external genitalia during fetal life, and for the development of secondary sex characteristics at puberty. Antimullerian hormone (AMH) secreted by Sertoli cells inhibits the development of female internal genitalia (tube, uterus, upper part of vagina); testosterone secreted by Leydig cells induces stabilization of wolffian ducts and development of internal male genitalia. Differentiation of external male genitalia requires the transformation of testosterone to dihydrotestosterone by 5alpha reductase type 2 expressed in genital skin and urogenital sinus. The effects of androgens occur in presence of functional androgen receptor (AR) protein. Mutations of genes coding for steroidogenic enzymes, AMH, AMH receptor, AR and 5alpha reductase are all associated with impairment of sex differentiation and result in genital ambiguity. PMID:12834017

  11. Nonlinear-optical frequency-doubling metareflector: pulsed regime

    NASA Astrophysics Data System (ADS)

    Popov, A. K.; Myslivets, S. A.

    2016-01-01

    The properties of backward-wave second-harmonic metareflector operating in pulse regime are investigated. It is made of metamaterial which enables phase matching of contra-propagating fundamental and second-harmonic waves. References are given to the works that prove such a possibility. Physical principles underlying differences in the proposed and standard settings as well as between continuous-wave and pulsed regimes are discussed. Pulsed regime is more practicable and has a broader scope of applications. A set of partial differential equations which describe such a reflector with the account for losses are solved numerically. It is shown that unlike second-harmonic generation in standard settings, contra-propagating pulse of second harmonic may become much longer than the incident fundamental one and the difference grows with decrease in the input pulse length as compared to thickness of the metaslab. The revealed properties are important for applications and may manifest themselves beyond the optical wavelength range.

  12. Pulse Coil Tester

    NASA Technical Reports Server (NTRS)

    Simon, Richard A.

    1988-01-01

    Set of relays tested easily and repeatedly. Pulse coil tester causes coil under test to generate transient voltage; waveform indicates condition of coil. Tester accommodates assembly of up to four coils at a time.

  13. HIGH POWER PULSED OSCILLATOR

    DOEpatents

    Singer, S.; Neher, L.K.

    1957-09-24

    A high powered, radio frequency pulse oscillator is described for generating trains of oscillations at the instant an input direct voltage is impressed, or immediately upon application of a light pulse. In one embodiment, the pulse oscillator comprises a photo-multiplier tube with the cathode connected to the first dynode by means of a resistor, and adjacent dynodes are connected to each other through adjustable resistors. The ohmage of the resistors progressively increases from a very low value for resistors adjacent the cathode to a high value adjacent the plate, the last dynode. Oscillation occurs with this circuit when a high negative voltage pulse is applied to the cathode and the photo cathode is bombarded. Another embodiment adds capacitors at the resistor connection points of the above circuit to increase the duration of the oscillator train.

  14. Pulsed mode cathode

    NASA Technical Reports Server (NTRS)

    Myers, Roger M. (Inventor); Rawlin, Vinvent K. (Inventor)

    1994-01-01

    A cathode in an MPD thruster has an internal heater and utilizes low work function material. The cathode is preheated to operating temperature, and then the thruster is fired by discharging a capacitor bank in a pulse forming network.

  15. Pulsed-neutron monochromator

    DOEpatents

    Mook, H.A. Jr.

    1984-01-01

    In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

  16. Pulsed-neutron monochromator

    DOEpatents

    Mook, Jr., Herbert A.

    1985-01-01

    In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

  17. Multiple pulse laser

    SciTech Connect

    Hughes, R.S.; Jernigan, J.L.

    1981-02-10

    A multiple pulse laser from a single resonant cavity is disclosed. An acousto-optic cell is used to modulate coherent light from a lasing element. Either multiple chirp signals or a masked mirror are used to provide distinct pulses of light. Through proper choice of materials for the acousto-optic cell and use of divergent optics, a higher power level is obtained. Use of a multi-tapped delay line permits a shorter period between pulses due to the linear superposition principle. When the mask embodiment is used, the acousto-optic cell focuses light which scans across the mask. Whenever the focused light passes through the mask, lasing occurs which generates an output pulse.

  18. Pulse measurement apparatus and method

    DOEpatents

    Marciante, John R.; Donaldson, William R.; Roides, Richard G.

    2011-10-25

    An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.

  19. Pulsed spallation neutron sources

    SciTech Connect

    Carpenter, J.M.

    1996-05-01

    This paper reviews the early history of pulsed spallation neutron source development ar Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provide a few examples of applications in fundamental condensed matter physics, materials science and technology.

  20. Pulsed spallation Neutron Sources

    SciTech Connect

    Carpenter, J.M.

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  1. RF Pulsed Heating

    NASA Astrophysics Data System (ADS)

    Pritzkau, D. P.

    2002-01-01

    RF pulsed heating is a process by which a metal is heated from magnetic elds on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic eld on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE011 mode at a resonant frequency of 11:424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1:5 s perent surface preparations.he cavity are designed to A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE012 mode to steady-state in the cavity at 18 GHz and measuring the change in re ected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 106 pulses. The second run was executed at a calculated temperature rise of 82 K for 86106 pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  2. Pulse magnetic welder

    DOEpatents

    Christiansen, D.W.; Brown, W.F.

    1984-01-01

    A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.

  3. Differentiation and the Twice-Exceptional Student

    ERIC Educational Resources Information Center

    Franklin-Rohr, Cheryl

    2012-01-01

    Tier 1, the first level of instruction in the RtI (Response to Intervention) framework, is designed to meet the needs of 80% of students within the regular classroom. The only way to accomplish this goal is to use differentiation. Differentiation is not a singular process; it is rather a complicated process of adapting instructional strategies so…

  4. A versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy.

    NASA Technical Reports Server (NTRS)

    Tarr, C. E.; Nickerson, M. A.

    1972-01-01

    A digital pulse programmer producing the standard pulse sequences required for pulsed nuclear magnetic resonance spectroscopy is described. In addition, a 'saturation burst' sequence, useful in the measurement of long relaxation times in solids, is provided. Both positive and negative 4 V trigger pulses are produced that are fully synchronous with a crystal-controlled time base, and the pulse programmer may be phase-locked with a maximum pulse jitter of 3 ns to the oscillator of a coherent pulse spectrometer. Medium speed TTL integrated circuits are used throughout.

  5. Laser Energy Monitor for Double-Pulsed 2-Micrometer IPDA Lidar Application

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Petros, Mulugeta; Remus, Ruben; Yu, Jirong; Singh, Upendra N.

    2014-01-01

    Integrated path differential absorption (IPDA) lidar is a remote sensing technique for monitoring different atmospheric species. The technique relies on wavelength differentiation between strong and weak absorbing features normalized to the transmitted energy. 2-micron double-pulsed IPDA lidar is best suited for atmospheric carbon dioxide measurements. In such case, the transmitter produces two successive laser pulses separated by short interval (200 microseconds), with low repetition rate (10Hz). Conventional laser energy monitors, based on thermal detectors, are suitable for low repetition rate single pulse lasers. Due to the short pulse interval in double-pulsed lasers, thermal energy monitors underestimate the total transmitted energy. This leads to measurement biases and errors in double-pulsed IPDA technique. The design and calibration of a 2-micron double-pulse laser energy monitor is presented. The design is based on a high-speed, extended range InGaAs pin quantum detectors suitable for separating the two pulse events. Pulse integration is applied for converting the detected pulse power into energy. Results are compared to a photo-electro-magnetic (PEM) detector for impulse response verification. Calibration included comparing the three detection technologies in single-pulsed mode, then comparing the pin and PEM detectors in double-pulsed mode. Energy monitor linearity will be addressed.

  6. LED flicker pulsing

    NASA Astrophysics Data System (ADS)

    Johnson, Mark A.; Cote, Paul J.

    2001-08-01

    There is need to replace hazardous radioluminescent light sources with a means of illumination that is environmentally friendly. This paper describes an electronic source that was developed as a potential candidate to replace low intensity tritium in a military system. It employs an LED for illumination and a 3-volt coin cell battery as a power source. This new light source is electronically invisible, requires minimal maintenance, and provides the lowest practical illumination to preclude detection by optical means. The low intensity requires that the LED be driven at DC current levels resulting in poor luminous efficiency. Therefore, in an effort to maximize battery life, the LED is pulsed into a more optically efficient mode of operation. However, conventional pulsing techniques are not employed because of concerns the electronics could be identified by conspicuous power spectral density (PSD) components in the electromagnetic spectrum generated by a pulsed LED. Therefore, flicker noise concepts have been employed to efficiently drive the LED while generating a virtually undetectable spectral signature. Although ideally the pulse durations, magnitudes, and spacings should be random, a significant reduction in conspicuous PSD components can be achieved when imposing practical constraints. The dominant components of the power spectrum are significantly reduced using fixed pulse durations and magnitudes while varying only the pulse spacing. The mean duty cycle is set to provide the same effective illumination as DC operation while generating a PSD normally associated with natural phenomena.

  7. Comparison of the Asynchronous Differential Evolution and JADE Minimization Algorithms

    NASA Astrophysics Data System (ADS)

    Zhabitsky, Mikhail

    2016-02-01

    Differential Evolution (DE) is an efficient evolutionary algorithm to solve global optimization problems. In this work we compare performance of the recently proposed Asynchronous Differential Evolution with Adaptive Correlation Matrix (ADEACM) to the widely used JADE algorithm, a DE variant with adaptive control parameters.

  8. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, R.B.

    1985-08-15

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  9. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, Russell B.

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  10. An adaptive level set method

    SciTech Connect

    Milne, R.B.

    1995-12-01

    This thesis describes a new method for the numerical solution of partial differential equations of the parabolic type on an adaptively refined mesh in two or more spatial dimensions. The method is motivated and developed in the context of the level set formulation for the curvature dependent propagation of surfaces in three dimensions. In that setting, it realizes the multiple advantages of decreased computational effort, localized accuracy enhancement, and compatibility with problems containing a range of length scales.

  11. Efficient optical pulse stacker system

    DOEpatents

    Seppala, Lynn G.; Haas, Roger A.

    1982-01-01

    Method and apparatus for spreading and angle-encoding each pulse of a multiplicity of small area, short pulses into several temporally staggered pulses by use of appropriate beam splitters, with the optical elements being arranged so that each staggered pulse is contiguous with one or two other such pulses, and the entire sequence of stacked pulses comprising a single, continuous long pulse. The single long pulse is expanded in area, and then doubly passed through a nonstorage laser amplifier such as KrF. After amplification, the physically separated, angle-encoded and temporally staggered pulses are recombined into a single pulse of short duration. This high intensity output beam is well collimated and may be propagated over long distance, or used for irradiating inertial confinement fusion targets.

  12. Acceleration of generalized adaptive pulse compression with parallel GPUs

    NASA Astrophysics Data System (ADS)

    Cai, Jingxiao; Zhang, Yan R.

    2015-05-01

    Super-computing based on Graphic Processing Unit (GPU) has become a booming field both in research and industry. In this paper, GPU is applied as the main computing device on traditional RADAR super resolution algorithms. Comparison is provided between GPU and CPU as computing architecture and MATLAB, as a widely used scientific implementation, is also included as well as C++ implementation in demonstrations of CPU part in the comparison. Fundamental RADAR algorithms as matched filter and least square estimation (LSE) are used as standard procedure to measure the efficiency of each implementation. Based on the result in this paper, GPU shows an enormous potential to expedite the traditional process of RADAR super-resolution applications.

  13. High voltage pulse generator

    DOEpatents

    Fasching, George E.

    1977-03-08

    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  14. Photoconductive circuit element pulse generator

    DOEpatents

    Rauscher, Christen

    1989-01-01

    A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.

  15. Adaptive immunity to fungi.

    PubMed

    Verma, Akash; Wüthrich, Marcel; Deepe, George; Klein, Bruce

    2014-11-06

    Life-threatening fungal infections have risen sharply in recent years, owing to the advances and intensity of medical care that may blunt immunity in patients. This emerging crisis has created the growing need to clarify immune defense mechanisms against fungi with the ultimate goal of therapeutic intervention. We describe recent insights in understanding the mammalian immune defenses that are deployed against pathogenic fungi. We focus on adaptive immunity to the major medically important fungi and emphasize three elements that coordinate the response: (1) dendritic cells and subsets that are mobilized against fungi in various anatomical compartments; (2) fungal molecular patterns and their corresponding receptors that signal responses and shape the differentiation of T-cell subsets and B cells; and, ultimately (3) the effector and regulatory mechanisms that eliminate these invaders while constraining collateral damage to vital tissue. These insights create a foundation for the development of new, immune-based strategies for prevention or enhanced clearance of systemic fungal diseases.

  16. Adaptive immunity to fungi.

    PubMed

    Wüthrich, Marcel; Deepe, George S; Klein, Bruce

    2012-01-01

    Only a handful of the more than 100,000 fungal species on our planet cause disease in humans, yet the number of life-threatening fungal infections in patients has recently skyrocketed as a result of advances in medical care that often suppress immunity intensely. This emerging crisis has created pressing needs to clarify immune defense mechanisms against fungi, with the ultimate goal of therapeutic applications. Herein, we describe recent insights in understanding the mammalian immune defenses deployed against pathogenic fungi. The review focuses on adaptive immune responses to the major medically important fungi and emphasizes how dendritic cells and subsets in various anatomic compartments respond to fungi, recognize their molecular patterns, and signal responses that nurture and shape the differentiation of T cell subsets and B cells. Also emphasized is how the latter deploy effector and regulatory mechanisms that eliminate these nasty invaders while also constraining collateral damage to vital tissue.

  17. Precipitation pulses and carbon fluxes in semiarid and arid ecosystems.

    PubMed

    Huxman, Travis E; Snyder, Keirith A; Tissue, David; Leffler, A Joshua; Ogle, Kiona; Pockman, William T; Sandquist, Darren R; Potts, Daniel L; Schwinning, Susan

    2004-10-01

    In the arid and semiarid regions of North America, discrete precipitation pulses are important triggers for biological activity. The timing and magnitude of these pulses may differentially affect the activity of plants and microbes, combining to influence the C balance of desert ecosystems. Here, we evaluate how a "pulse" of water influences physiological activity in plants, soils and ecosystems, and how characteristics, such as precipitation pulse size and frequency are important controllers of biological and physical processes in arid land ecosystems. We show that pulse size regulates C balance by determining the temporal duration of activity for different components of the biota. Microbial respiration responds to very small events, but the relationship between pulse size and duration of activity likely saturates at moderate event sizes. Photosynthetic activity of vascular plants generally increases following relatively larger pulses or a series of small pulses. In this case, the duration of physiological activity is an increasing function of pulse size up to events that are infrequent in these hydroclimatological regions. This differential responsiveness of photosynthesis and respiration results in arid ecosystems acting as immediate C sources to the atmosphere following rainfall, with subsequent periods of C accumulation should pulse size be sufficient to initiate vascular plant activity. Using the average pulse size distributions in the North American deserts, a simple modeling exercise shows that net ecosystem exchange of CO2 is sensitive to changes in the event size distribution representative of wet and dry years. An important regulator of the pulse response is initial soil and canopy conditions and the physical structuring of bare soil and beneath canopy patches on the landscape. Initial condition influences responses to pulses of varying magnitude, while bare soil/beneath canopy patches interact to introduce nonlinearity in the relationship between pulse

  18. A Novel Pulse-Chase Paradigm to Visualize the Trafficking of Transport Vesicles in Neurons

    NASA Astrophysics Data System (ADS)

    Al-Bassam, Sarmad

    In neurons transmembrane proteins are targeted to dendrites in vesicles that traffic solely within the somatodendritic compartment. How these vesicles are retained within the somatodendritic domain is unknown. Here we adapt a novel pulse chase system that allows synchronous release of exogenous transmembrane proteins from the endoplasmic reticulum using FKBP12 and Rapamycin. We demonstrate proof-of-concept and establish protein trafficking controls in incremental steps. We demonstrate the utility of this approach in studying protein trafficking and establish parameters for analysis of time-lapse images. We implement this novel pulse-chase strategy to track the movements of post-Golgi transport vesicles. Surprisingly, we found that post-Golgi vesicles carrying dendritic proteins were equally likely to enter axons and dendrites. However, once such vesicles entered the axon they very rarely moved beyond the axon initial segment, but instead either halted or reversed direction in an actin and Myosin Va-dependent manner. In contrast, vesicles carrying either an axonal or a nonspecifically localized protein only rarely halted or reversed and instead generally proceeded to the distal axon. Thus, our results are consistent with the axon initial segment behaving as a vesicle filter that mediates the differential trafficking of transport vesicles.

  19. Pulse Wave Propagation in the Arterial Tree

    NASA Astrophysics Data System (ADS)

    van de Vosse, Frans N.; Stergiopulos, Nikos

    2011-01-01

    The beating heart creates blood pressure and flow pulsations that propagate as waves through the arterial tree that are reflected at transitions in arterial geometry and elasticity. Waves carry information about the matter in which they propagate. Therefore, modeling of arterial wave propagation extends our knowledge about the functioning of the cardiovascular system and provides a means to diagnose disorders and predict the outcome of medical interventions. In this review we focus on the physical and mathematical modeling of pulse wave propagation, based on general fluid dynamical principles. In addition we present potential applications in cardiovascular research and clinical practice. Models of short- and long-term adaptation of the arterial system and methods that deal with uncertainties in personalized model parameters and boundary conditions are briefly discussed, as they are believed to be major topics for further study and will boost the significance of arterial pulse wave modeling even more.

  20. HydroPulse Drilling

    SciTech Connect

    J.J. Kolle

    2004-04-01

    Tempress HydroPulse{trademark} tool increases overbalanced drilling rates by generating intense suction pulses at the drill bit. This report describes the operation of the tool; results of pressure drilling tests, wear tests and downhole drilling tests; and the business case for field applications. The HydroPulse{trademark} tool is designed to operate on weighted drilling mud at conventional flow rates and pressures. Pressure drilling tests confirm that the HydroPulse{trademark} tool provides 33% to 200% increased rate of penetration. Field tests demonstrated conventional rotary and mud motor drilling operations. The tool has been operated continuous for 50 hours on weighted mud in a wear test stand. This level of reliability is the threshold for commercial application. A seismic-while-drilling version of the tool was also developed and tested. This tool was used to demonstrate reverse vertical seismic profiling while drilling an inclined test well with a PDC bit. The primary applications for the HydroPulse{trademark} tool are deep onshore and offshore drilling where rate of penetration drives costs. The application of the seismic tool is vertical seismic profiling-while-drilling and look-ahead seismic imaging while drilling.

  1. Kilovolt Blumlein pulse generator with variable pulse duration and polarity

    NASA Astrophysics Data System (ADS)

    de Angelis, Andrea; Kolb, Juergen F.; Zeni, Luigi; Schoenbach, Karl H.

    2008-04-01

    A Blumlein pulse generator which utilizes the superposition of electrical pulses launched from two individually switched pulse forming lines has been designed and tested. By using a power metal-oxide-semiconductor field-effect transistor as a switch on each end of the Blumlein line, we were able to generate pulses with amplitudes of 1kV across a 100Ω load. Pulse duration and polarity can be controlled by the temporal delay in the triggering of the two switches. Using this technique, we have demonstrated the generation of pulses with durations between 8 and 60ns. The lower limit in pulse duration was determined by the switch closing time and the upper limit by the length of the pulse forming line. A further advantage of the concept is that pulse distortions caused by the non-negligible on-resistance of a line with a single switch can be eliminated by using switches with identical characteristics.

  2. Kilovolt Blumlein pulse generator with variable pulse duration and polarity.

    PubMed

    de Angelis, Andrea; Kolb, Juergen F; Zeni, Luigi; Schoenbach, Karl H

    2008-04-01

    A Blumlein pulse generator which utilizes the superposition of electrical pulses launched from two individually switched pulse forming lines has been designed and tested. By using a power metal-oxide-semiconductor field-effect transistor as a switch on each end of the Blumlein line, we were able to generate pulses with amplitudes of 1 kV across a 100 Omega load. Pulse duration and polarity can be controlled by the temporal delay in the triggering of the two switches. Using this technique, we have demonstrated the generation of pulses with durations between 8 and 60 ns. The lower limit in pulse duration was determined by the switch closing time and the upper limit by the length of the pulse forming line. A further advantage of the concept is that pulse distortions caused by the non-negligible on-resistance of a line with a single switch can be eliminated by using switches with identical characteristics.

  3. Adaptive encoding in the visual pathway.

    PubMed

    Lesica, Nicholas A; Boloori, Alireza S; Stanley, Garrett B

    2003-02-01

    In a natural setting, the mean luminance and contrast of the light within a visual neuron's receptive field are constantly changing as the eyes saccade across complex scenes. Adaptive mechanisms modulate filtering properties of the early visual pathway in response to these variations, allowing the system to maintain differential sensitivity to nonstationary stimuli. An adaptive variant of the reverse correlation technique is used to characterize these changes during single trials. Properties of the adaptive reverse correlation algorithm were investigated via simulation. Analysis of data collected from the mammalian visual system demonstrates the ability to continuously track adaptive changes in the encoding scheme. The adaptive estimation approach provides a framework for characterizing the role of adaptation in natural scene viewing. PMID:12613554

  4. Bacterial differentiation.

    PubMed

    Shapiro, L; Agabian-Keshishian, N; Bendis, I

    1971-09-01

    The foregoing studies are intended to define a differentiation process and to permit genetic access to the mechanisms that control this process. In order to elucidate the basic mechanisms whereby a cell dictates its own defined morphogenic changes, we have found it helpful to study an organism that can be manipulated both biochemically and genetically. We have attempted to develop the studies initiated by Poindexter,Stove and Stanier, and Schmidt and Stanier (16, 17, 20) with the Caulobacter genus so that these bacteria can serve as a model system for prokaryotic differentiation. The Caulobacter life cycle, defined in synchronously growing cultures, includes a sequential series of morphological changes that occur at specific times in the cycle and at specific locations in the cell. Six distinct cellular characteristics, which are peculiar to these bacteria, have been defined and include (i) the synthesis of a polar organelle which may be membranous (21-23), (ii) a satellite DNA in the stalked cell (26), (iii) pili to which RNA bacteriophage specifically adsorb (16, 33), (iv) a single polar flagellum(17), (v) a lipopolysaccharide phage receptor site (27), and (vi) new cell wall material at the flagellated pole of the cell giving rise to a stalk (19, 20). Cell division, essential for the viability of the organism, is dependent on the irreversible differentiation of a flagellated swarmer cell to a mature stalked cell. The specific features of the Caulobacter system which make it a system of choice for studies of the control of sequential events resulting in cellular differentiation can be summarized as follows. 1) Cell populations can be synchronized, and homogeneous populations at each stage in the differentiation cycle can thus be obtained. 2) A specific technique has been developed whereby the progress of the differentiation cycle can be accurately measured by adsorption of labeled RNA phage or penetration of labeled phage DNA into specific cell forms. This

  5. Spatiotemporal optical pulse transformation by a resonant diffraction grating

    SciTech Connect

    Golovastikov, N. V.; Bykov, D. A. Doskolovich, L. L. Soifer, V. A.

    2015-11-15

    The diffraction of a spatiotemporal optical pulse by a resonant diffraction grating is considered. The pulse diffraction is described in terms of the signal (the spatiotemporal incident pulse envelope) passage through a linear system. An analytic approximation in the form of a rational function of two variables corresponding to the angular and spatial frequencies has been obtained for the transfer function of the system. A hyperbolic partial differential equation describing the general form of the incident pulse envelope transformation upon diffraction by a resonant diffraction grating has been derived from the transfer function. A solution of this equation has been obtained for the case of normal incidence of a pulse with a central frequency lying near the guided-mode resonance of a diffraction structure. The presented results of numerical simulations of pulse diffraction by a resonant grating show profound changes in the pulse envelope shape that closely correspond to the proposed theoretical description. The results of the paper can be applied in creating new devices for optical pulse shape transformation, in optical information processing problems, and analog optical computations.

  6. Coherent excitation with short electron pulses

    NASA Astrophysics Data System (ADS)

    Guertler, Andreas; Robicheaux, Francis; Noordam, Bart

    2000-06-01

    [1pt] The probability for a transition within an atom to be driven by a collision with a long pulse of electrons is proportional to the electron flux with the proportionality factor being the cross section for this transition. Recently it was shown [1] that for electron pulses shorter than the orbit time of the electron in the atom, a contribution of coherent scattering plays a role, which is proportional to the differential cross section in forward direction and the square of the electron flux. To investigate this effect, we are developing a picosecond electron gun [2]. Collision experiments will be done with Rydberg states in lithium around n=40 with Kepler orbit times in the order of 10 ps. For picosecond electron pulses, a quadratic dependance of the transition probability on the electron flux is expected in contrast to the linear dependance expected for nanosecond electron pulses. [1pt] References [1pt] [1] F. Robicheaux and L. D. Noordam, submitted to Phys. Rev. Lett. [1pt] [2] F. Robicheaux, G. M. Lankhuijzen, and L. D. Noordam, JOSA B 15, 1 (1998)

  7. Laser pulse sampler

    DOEpatents

    Vann, C.

    1998-03-24

    The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera. 5 figs.

  8. Laser pulse sampler

    DOEpatents

    Vann, Charles

    1998-01-01

    The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera.

  9. Pulse shaping system

    DOEpatents

    Skeldon, Mark D.; Letzring, Samuel A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

  10. Pulse shaping system

    DOEpatents

    Skeldon, M.D.; Letzring, S.A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

  11. Micro pulse lidar

    SciTech Connect

    Spinhirne, J.D. )

    1993-01-01

    An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering has been demonstrated. The transmitter of the micro pulse lidar is a diode pumped [mu]J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view (FOV) and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited by optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that systems built on the micro pulse lidar concept are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

  12. Pulsed neutron detector

    DOEpatents

    Robertson, deceased, J. Craig; Rowland, Mark S.

    1989-03-21

    A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

  13. Pulsed welding plasma source

    NASA Astrophysics Data System (ADS)

    Knyaz'kov, A.; Pustovykh, O.; Verevkin, A.; Terekhin, V.; Shachek, A.; Tyasto, A.

    2016-04-01

    It is shown that in order to form the current pulse of a near rectangular shape, which provides conversion of the welding arc into a dynamic mode, it is rational to connect a forming element made on the basis of an artificial forming line in series to the welding DC circuit. The paper presents a diagram of a pulsed device for welding with a non-consumable electrode in argon which was developed using the forming element. The conversion of the arc into the dynamic mode is illustrated by the current and voltage oscillograms of the arc gap and the dynamic characteristic of the arc within the interval of one pulse generation time in the arc gap. The background current travels in the interpulse interval.

  14. Pulse power linac

    DOEpatents

    Villa, Francesco

    1990-01-01

    A linear acceleration for charged particles is constructed of a plurality of transmission line sections that extend between a power injection region and an accelerating region. Each line section is constructed of spaced plate-like conductors and is coupled to an accelerating gap located at the accelerating region. Each gap is formed between a pair of apertured electrodes, with all of the electrode apertures being aligned along a particle accelerating path. The accelerating gaps are arranged in series, and at the injection region the line sections are connected in parallel. At the injection region a power pulse is applied simultaneously to all line sections. The line sections are graduated in length so that the pulse reaches the gaps in a coordinated sequence whereby pulse energy is applied to particles as they reach each of the gaps along the accelerating path.

  15. Genetic interactions between diverged alleles of Early heading date 1 (Ehd1) and Heading date 3a (Hd3a)/ RICE FLOWERING LOCUS T1 (RFT1) control differential heading and contribute to regional adaptation in rice (Oryza sativa).

    PubMed

    Zhao, Jing; Chen, Hongyi; Ren, Ding; Tang, Huiwu; Qiu, Rong; Feng, Jinglei; Long, Yunming; Niu, Baixiao; Chen, Danping; Zhong, Tianyu; Liu, Yao-Guang; Guo, Jingxin

    2015-11-01

    Initiation of flowering, also called heading, in rice (Oryza sativa) is determined by the florigens encoded by Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T1 (RFT1). Early heading date 1 (Ehd1) regulates Hd3a and RFT1. However, different rice varieties have diverged alleles of Ehd1 and Hd3a/RFT1 and their genetic interactions remain largely unclear. Here we generated three segregating populations for different combinations of diverged Ehd1 and Hd3a/RFT1 alleles, and analyzed their genetic interactions between these alleles. We demonstrated that, in an ehd1 mutant background, Hd3a was silenced, but RFT1 was expressed (although at lower levels than in plants with a functional Ehd1) under short-day (SD) and long-day (LD) conditions. We identified a nonfunctional RFT1 allele (rft1); the lines carrying homozygous ehd1 and Hd3a/rft1 failed to induce the floral transition under SD and LD conditions. Like Hd3a, RFT1 also interacted with 14-3-3 proteins, the florigen receptors, but a nonfunctional RFT1 with a crucial E105K mutation failed to interact with 14-3-3 proteins. Furthermore, analyses of sequence variation and geographic distribution suggested that functional RFT1 alleles were selected during rice adaptation to high-latitude regions. Our results demonstrate the important roles of RFT1 in rice flowering and regional adaptation.

  16. Security of the differential-quadrature-phase-shift quantum key distribution

    NASA Astrophysics Data System (ADS)

    Kawakami, Shun; Sasaki, Toshihiko; Koashi, Masato

    2016-08-01

    One of the simplest methods for implementing quantum key distribution over fiber-optic communication is the Bennett-Brassard 1984 protocol with phase encoding (PE-BB84 protocol), in which the sender uses phase modulation over double pulses from a laser and the receiver uses a passive delayed interferometer. Using essentially the same setup and by regarding a train of many pulses as a single block, one can carry out the so-called differential-quadrature-phase-shift (DQPS) protocol, which is a variant of differential-phase-shift (DPS) protocols. Here we prove the security of the DQPS protocol based on an adaptation of proof techniques for the BB84 protocol, which inherits the advantages arising from the simplicity of the protocol, such as accommodating the use of threshold detectors and simple off-line calibration methods for the light source. We show that the secure key rate of the DQPS protocol in the proof is eight-thirds as high as the rate of the PE-BB84 protocol.

  17. Observation, Manipulation and Control of Femtosecond Pulse Propagation in Optical Fibers

    NASA Astrophysics Data System (ADS)

    Taylor, Antoinette

    2003-03-01

    Adaptive control, in combination with ultrafast pulse shaping techniques provides a compelling approach to harness events that occur on the fastest timescales, with fundamental applications in both the basic and applied sciences [1]. In this talk we describe the application of adaptive pulse shaping to femtosecond (fs) pulse propagation at a wavelength of 1550 nm in single mode fiber. With this method, through feedback control, light fields are designed with specific fs features to optimize specific parameters in the nonlinear propagation of fs pulses in optical fibers. Numerical simulations, based on the nonlinear Schrodinger equation, are presented to motivate and illustrate the power of this adaptive technique applied to fs pulse propagation in fibers [2]. Experimental implementations of this technique are then described where we demonstrate that it is possible to defeat higher order nonlinear effects through the use of an adaptive control feedback loop that acts on the spectral phase of the fs optical pulses launched in the fiber [3,4]. In one set of experiments, compensation for significant (>50through the propagation of 200 fs pulses in the nonlinear regime is demonstrated by suitably pre-shaping the input pulse using an adaptive feedback loop. In a second set of experiments, we demonstrate the use of adaptive feedback to control the amount of Raman self-frequency shift. The ultimate goal in these experiments is to transmit the maximum amount of energy in a short pulse in a highly nonlinear regime through the fiber. [1] R. S. Judson and H. Rabitz, Phys. Rev. Lett. 68, 1500 (1992). [2] F. G. Omenetto, B. P. Luce, and A. J. Taylor, J. Opt. Soc. Amer. B 16, 2005 (1999). [3] F. G. Omenetto, A. J. Taylor, M. D. Moores, and D. H. Reitze, Opt. Lett. 26, 938 (2001). [4] F. G. Omenetto, D. H. Reitze, B. P. Luce, M. D. Moores, and A. J. Taylor, IEEE J. Sel. Top. Quantum Electron. 8, 690 (2002).

  18. Development of pulsed gas discharge lasers for shock hardening

    NASA Astrophysics Data System (ADS)

    Hintz, Gerd; Tkotz, R.; Keusch, C.; Negendanck, Matthias; Christiansen, Jens; Hoffmann, D. H. H.

    1996-08-01

    Shock hardening of metals (e.g. Ti, stainless steel) by pulsed lasers offers the possibility of large hardening depth (several millimeters) without serious damage to the surface of the workpiece. Previous investigations for shock hardening have mainly been performed with high power solid state lasers. The adaptation of commercial, high power gas discharge lasers to the shock hardening process could make this process relevant for industrial applications, as high repetition rates may be used. Two different laser systems have been investigated: a TEA carbon-dioxide laser and a XeCl laser. Both systems have pulse energies of some joule, a pulse length of several ten nanoseconds, and pulse repetition rates of up to 10 Hertz. The divergence of the beam was minimized to improve focusing properties. Systematic measurements of the laser induced pressure by means of piezo probes have been performed. An enhancement of the hardness of illuminated Ti(RT15) targets has been found and is reported.

  19. An Overview of High Energy Short Pulse Technology for Advanced Radiography of Laser Fusion Experiments

    SciTech Connect

    Barty, C J; Key, M; Britten, J; Beach, R; Beer, G; Brown, C; Bryan, S; Caird, J; Carlson, T; Crane, J; Dawson, J; Erlandson, A C; Fittinghoff, D; Hermann, M; Hoaglan, C; Iyer, A; Jones, L; Jovanovic, I; Komashko, A; Landen, O; Liao, Z; Molander, W; Mitchell, A; Moses, E; Nielsen, N; Nguyen, H; Nissen, J; Payne, S; Pennington, D; Risinger, L; Rushford, M; Skulina, K; Spaeth, M; Stuart, B; Tietbohl, G; Wattellier, B

    2004-06-18

    The technical challenges and motivations for high-energy, short-pulse generation with NIF-class, Nd:glass laser systems are reviewed. High energy short pulse generation (multi-kilojoule, picosecond pulses) will be possible via the adaptation of chirped pulse amplification laser techniques on the NIF. Development of meter-scale, high efficiency, high-damage-threshold final optics is a key technical challenge. In addition, deployment of HEPW pulses on NIF is constrained by existing laser infrastructure and requires new, compact compressor designs and short-pulse, fiber-based, seed-laser systems. The key motivations for high energy petawatt pulses on NIF is briefly outlined and includes high-energy, x-ray radiography, proton beam radiography, proton isochoric heating and tests of the fast ignitor concept for inertial confinement fusion.

  20. SNMR pulse sequence phase cycling

    DOEpatents

    Walsh, David O; Grunewald, Elliot D

    2013-11-12

    Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.