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Sample records for repetition frequency prf

  1. Noninvasive MRI thermometry with the proton resonance frequency (PRF) method: in vivo results in human muscle

    DEFF Research Database (Denmark)

    De Poorter, J; De Wagter, C; De Deene, Y

    1995-01-01

    The noninvasive thermometry method is based on the temperature dependence of the proton resonance frequency (PRF). High-quality temperature images can be obtained from phase information of standard gradient-echo sequences with an accuracy of 0.2 degrees C in phantoms. This work was focused...

  2. Investigation of the lasing characteristics of a barium vapor laser with pulse repetition frequencies up to 320 kHz for navigation

    Science.gov (United States)

    Soldatov, A. N.; Polunin, Yu. P.

    2015-11-01

    Results of experimental investigations into the characteristics of a laser on self-terminating transitions of the barium atom with λ = 1499 nm are presented for high pulse repetition frequencies (PRF). The frequency-energy characteristics are investigated in the self-heating mode of laser operation. Record values of PRF for the barium vapor laser, equal to ~320 kHz, have been attained.

  3. Digital repetitive control under varying frequency conditions

    CERN Document Server

    Ramos, Germán A; Olm, Josep M

    2013-01-01

    The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area. Repetitive Control has proven to be an efficient way to face this topic. However, in some applications the frequency of the reference/disturbance signal is time-varying or uncertain. This causes an important performance degradation in the standard Repetitive Control scheme. This book presents some solutions to apply Repetitive Control in varying frequency conditions without loosing steady-state performance. It also includes a complete theoretical development and experimental results in two representative systems. The presented solutions are organized in two complementary branches: varying sampling period Repetitive Control and High Order Repetitive Control. The first approach allows dealing with large range frequency variations while the second allows dealing with small range frequency variations. The book also presents applications of the described techniques to a Roto-magnet plant and...

  4. Micromotion feature extraction of radar target using tracking pulses with adaptive pulse repetition frequency adjustment

    Science.gov (United States)

    Chen, Yijun; Zhang, Qun; Ma, Changzheng; Luo, Ying; Yeo, Tat Soon

    2014-01-01

    In multifunction phased array radar systems, different activities (e.g., tracking, searching, imaging, feature extraction, recognition, etc.) would need to be performed simultaneously. To relieve the conflict of the radar resource distribution, a micromotion feature extraction method using tracking pulses with adaptive pulse repetition frequencies (PRFs) is proposed in this paper. In this method, the idea of a varying PRF is utilized to solve the frequency-domain aliasing problem of the micro-Doppler signal. With appropriate atom set construction, the micromotion feature can be extracted and the image of the target can be obtained based on the Orthogonal Matching Pursuit algorithm. In our algorithm, the micromotion feature of a radar target is extracted from the tracking pulses and the quality of the constructed image is fed back into the radar system to adaptively adjust the PRF of the tracking pulses. Finally, simulation results illustrate the effectiveness of the proposed method.

  5. All solid-state high power microwave source with high repetition frequency.

    Science.gov (United States)

    Bragg, J-W B; Sullivan, W W; Mauch, D; Neuber, A A; Dickens, J C

    2013-05-01

    An all solid-state, megawatt-class high power microwave system featuring a silicon carbide (SiC) photoconductive semiconductor switch (PCSS) and a ferrimagnetic-based, coaxial nonlinear transmission line (NLTL) is presented. A 1.62 cm(2), 50 kV 4H-SiC PCSS is hard-switched to produce electrical pulses with 7 ns full width-half max (FWHM) pulse widths at 2 ns risetimes in single shot and burst-mode operation. The PCSS resistance drops to sub-ohm when illuminated with approximately 3 mJ of laser energy at 355 nm (tripled Nd:YAG) in a single pulse. Utilizing a fiber optic based optical delivery system, a laser pulse train of four 7 ns (FWHM) signals was generated at 65 MHz repetition frequency. The resulting electrical pulse train from the PCSS closely follows the optical input and is utilized to feed the NLTL generating microwave pulses with a base microwave-frequency of about 2.1 GHz at 65 MHz pulse repetition frequency (prf). Under typical experimental conditions, the NLTL produces sharpened output risetimes of 120 ps and microwave oscillations at 2-4 GHz that are generated due to damped gyromagnetic precession of the ferrimagnetic material's axially pre-biased magnetic moments. The complete system is discussed in detail with its output matched into 50 Ω, and results covering MHz-prf in burst-mode operation as well as frequency agility in single shot operation are discussed.

  6. Digital repetitive control under varying frequency conditions

    OpenAIRE

    Ramos Fuentes, Germán Andrés

    2012-01-01

    The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area and Repetitive Control has proven to be an efficient way to face this topic; however, in some applications the period of the signal to be tracked/rejected changes in time or is uncertain, which causes and important performance degradation in the standard repetitive controller. This thesis presents some contributions to the open topic of repetitive control workin...

  7. 486nm blue laser operating at 500 kHz pulse repetition frequency

    Science.gov (United States)

    Creeden, Daniel; Blanchard, Jon; Pretorius, Herman; Limongelli, Julia; Setzler, Scott D.

    2016-03-01

    Compact, high power blue light in the 470-490nm region is difficult to generate due to the lack of laser sources which are easily convertible (through parametric processes) to those wavelengths. By using a pulsed Tm-doped fiber laser as a pump source for a 2-stage second harmonic generation (SHG) scheme, we have generated ~2W of 486.5nm light at 500kHz pulse repetition frequency (PRF). To our knowledge, this is the highest PRF and output power achieved in the blue region based on a frequency converted, monolithic fiber laser. This pump laser is a pulsed Tm-doped fiber laser/amplifier which generates 12.8W of 1946nm power at 500kHz PRF with diffraction-limited output from a purely single-mode fiber. The output from this laser is converted to 973nm through second harmonic generation (SHG). The 973nm is then converted to 486.5nm via another SHG stage. This architecture operates with very low peak power, which can be challenging from a nonlinear conversion standpoint. However, the low peak power enables the use of a single-mode monolithic fiber amplifier without undergoing nonlinear effects in the fiber. This also eliminates the need for novel fiber designs, large-mode area fiber, or free-space coupling to rod-type amplifiers, improving reliability and robustness of the laser source. Higher power and conversion efficiency are possible through the addition of Tm-doped fiber amplification stages as well as optimization of the nonlinear conversion process and nonlinear materials. In this paper, we discuss the laser layout, results, and challenges with generating blue light using a low peak power approach.

  8. Digital repetitive control under varying frequency conditions

    OpenAIRE

    Ramos Fuentes, Germán Andrés

    2012-01-01

    Premi extraordinari doctorat curs 2011-2012, àmbit d’Enginyeria Industrial The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area and Repetitive Control has proven to be an efficient way to face this topic; however, in some applications the period of the signal to be tracked/rejected changes in time or is uncertain, which causes and important performance degradation in the standard repetitive controller. This the...

  9. Staggered Multiple-PRF Ultrafast Color Doppler.

    Science.gov (United States)

    Posada, Daniel; Poree, Jonathan; Pellissier, Arnaud; Chayer, Boris; Tournoux, Francois; Cloutier, Guy; Garcia, Damien

    2016-06-01

    Color Doppler imaging is an established pulsed ultrasound technique to visualize blood flow non-invasively. High-frame-rate (ultrafast) color Doppler, by emissions of plane or circular wavefronts, allows severalfold increase in frame rates. Conventional and ultrafast color Doppler are both limited by the range-velocity dilemma, which may result in velocity folding (aliasing) for large depths and/or large velocities. We investigated multiple pulse-repetition-frequency (PRF) emissions arranged in a series of staggered intervals to remove aliasing in ultrafast color Doppler. Staggered PRF is an emission process where time delays between successive pulse transmissions change in an alternating way. We tested staggered dual- and triple-PRF ultrafast color Doppler, 1) in vitro in a spinning disc and a free jet flow, and 2) in vivo in a human left ventricle. The in vitro results showed that the Nyquist velocity could be extended to up to 6 times the conventional limit. We found coefficients of determination r(2) ≥ 0.98 between the de-aliased and ground-truth velocities. Consistent de-aliased Doppler images were also obtained in the human left heart. Our results demonstrate that staggered multiple-PRF ultrafast color Doppler is efficient for high-velocity high-frame-rate blood flow imaging. This is particularly relevant for new developments in ultrasound imaging relying on accurate velocity measurements.

  10. Megawatt, 330 Hz PRF tunable gyrotron experiments

    Science.gov (United States)

    Spark, S. N.; Cross, A. W.; Phelps, A. D. R.; Ronald, K.

    1994-12-01

    Repetitively pulsed and cw gyrotrons have hitherto used thermionic cathodes, whereas cold cathode gyrotrons have normally operated as ‘single shot’ devices. The novel results presented here show that cold cathode gyrotrons can be successfully pulsed repetitively. A tunable gyrotron with a pulse repetition frequency (PRF) of 150Hz is demonstrated. This system developed >4MW mm-wave output pulses at 100GHz. The gyrotron is based on a two-electrode configuration comprising a field-immersed, field emission, cold cathode and a shaped anode cavity. A superconducting magnet was used to produce the homogeneous intra-cavity magnetic field and a cable pulser was used to drive the electron beam. This pulser produced up to a (200±20)kV pulse with 10ns rise time, a 100ns flat top, a 10ns decay with a characteristic impedance of 200Ω. The energy storage capacity of the cable pulser was 35J. The charging unit limited the maximum PRF to 330Hz. Due to spark gap switching limitations 330Hz was only obtainable in 5 to 10 pulse bursts. For substantial periods of the order of 30 seconds, 100Hz PRF was achieved over an oscillating range of 28 to 100GHz and 150Hz PRF was achieved at 80GHz. No degradation effects on the mm-wave output pulse was evident due to diode recovery time throughout this series of results. A subsequent conclusion is that the diode recovery time in our cold cathode gyrotron is less than 3ms.

  11. Influence of shock wave pressure amplitude and pulse repetition frequency on the lifespan, size and number of transient cavities in the field of an electromagnetic lithotripter

    Science.gov (United States)

    Huber, Peter; Jöchle, Knut; Debus, Jürgen

    1998-10-01

    Monitoring the generation of cavitation is of great interest for diagnostic and therapeutic use of ultrasound in medicine, since cavitation is considered to play a major role in nonthermal ultrasound interactions with tissue. Important parameters are the number of cavitation events and the energy released during the bubble collapse. This energy is correlated to the maximum bubble radius which is related to the cavitation lifespan. The aim of this study was therefore to investigate the influence of the acoustic pressure amplitude and the pulse repetition frequency (PRF) in the field of a lithotripter (Lithostar, Siemens) on the number, size and lifespan of transient cavitation bubbles in water. We used scattered laser light recorded by a photodiode and stroboscopic photographs to monitor the cavitation activity. We found that PRF (range 0.5-5 Hz) had no influence on the cavitation bubble lifespan and size, whereas lifespan and size increased with the acoustic pressure amplitude. In contrast, the number of cavitation events strongly increased with PRF, whereas the pressure amplitude had no significant influence on the number of cavitation events. Thus, by varying the pressure amplitude and PRF, it might be possible to deliver a defined relative number of cavitations at a defined relative energy level in a defined volume. This seems to be relevant to further studies that address the biological effects of transient cavitation occurring in the fields of lithotripters.

  12. PRF-ambiguity resolution for SAR by contrast minimization in range-Doppler domain

    Institute of Scientific and Technical Information of China (English)

    YU Mingcheng; XU Jia; PENG Yingning

    2007-01-01

    An algorithm was developed to accurately estimate the Doppler centroid,which is needed for high-quality synthetic aperture radar(SAR)image formation by resolving the SAR pulse repetition frequency(PRF)ambiguity.The algorithm uses the SAR range migration to resolve the PRF-ambiguity by searching for a PRF-ambiguity number that minimizes the intensity contrast in the range-Doppler domain.Experimental results show that the approach.compared with traditional methods for resolving the SAR PRF ambiguity,is more suitable for both high contrast scenes such as urban areas and low contrast scenes such as mountains.Moreover,the approach is more computationally efficient for there are no time-consuming correlations or fast Fourier transform(FFT)operations needed in the range-Doppler domain and only part of the range cells are used in the calculation.

  13. Bottle microresonator broadband and low repetition rate frequency comb generator

    CERN Document Server

    Dvoyrin, V

    2016-01-01

    We propose a new type of broadband and low repetition rate frequency comb generator which has the shape of an elongated and nanoscale-shallow optical bottle microresonator created at the surface of an optical fiber. The free spectral range (FSR) of the broadband azimuthal eigenfrequency series of this resonator is the exact multiple of the FSR of the dense and narrowband axial series. The effective radius variation of the microresonator is close to a parabola with a nanoscale height which is greater or equal to lambda/2pi*n0 (here lambda is the characteristic radiation wavelength and n0 is the refractive index of the microresonator material). Overall, the microresonator possesses a broadband, small FSR, and accurately equidistant spectrum convenient for the generation of a broadband and low repetition rate optical frequency comb. It is shown that this comb can be generated by pumping with a cw laser, which radiation frequency matches a single axial eigenfrequency of the microresonator, or, alternatively, by p...

  14. Novel PRF Schedules for Medium PRF Radar

    Science.gov (United States)

    2005-04-14

    by the algorithm. Each potential PRF set is nted by one chromosome. This is the genetic description solution and may be broken into sections called...pr perform airborn PRF se Repe optimal These optima algorith The 2 of N illumin within achieve 3 of N s and the 14% im over a improv (60 to 1 the dom

  15. PRF Ambiguity Detrmination for Radarsat ScanSAR System

    Science.gov (United States)

    Jin, Michael Y.

    1998-01-01

    PRF ambiguity is a potential problem for a spaceborne SAR operated at high frequencies. For a strip mode SAR, there were several approaches to solve this problem. This paper, however, addresses PRF ambiguity determination algorithms suitable for a burst mode SAR system such as the Radarsat ScanSAR. The candidate algorithms include the wavelength diversity algorithm, range look cross correlation algorithm, and multi-PRF algorithm.

  16. Frequency Adaptive Repetitive Control of Grid-Tied Three-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    Repetitive control offers an accurate current control scheme for grid-tied converters to feed high quality sinusoidal current into the grid. However, with grid frequency being treated as a constant value, conventional repetitive controller fail to produce high quality feeding current...

  17. High Energy Single Frequency Fiber Laser at Low Repetition Rate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system operating at low repetition rate of 10 Hz to 1 kHz for coherent Lidar systems...

  18. Frequency Adaptive Repetitive Control of Grid-Tied Three-Phase PV iInverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    in the presence of practical time-varying grid frequency. This paper explores frequency adaptive repetitive control strategy for grid-interfaced converters, which employs fractional delay filter to adapt to the change of grid frequency. Case studies with experimental results of three-phase grid-connected...... converter systems are provided to verify the proposed controller....

  19. Frequency Adaptive Repetitive Control of Grid-Tied Single-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    . This paper thus explores a frequency adaptive repetitive control strategy for grid converters, which employs fractional delay filters in order to adapt to the change of the grid frequency. Case studies with experimental results of a single-phase grid-connected PV inverter system are provided to verify...

  20. Effects of cue frequency and repetition on prospective memory: an ERP investigation.

    Science.gov (United States)

    Wilson, Jennifer; Cutmore, Tim R H; Wang, Ya; Chan, Raymond C K; Shum, David H K

    2013-11-01

    Prospective memory involves the formation and completion of delayed intentions and is essential for independent living. In this study (n = 33), event-related potentials (ERPs) were used to systematically evaluate the effects of PM cue frequency (10% versus 30%) and PM cue repetition (high versus low) on ERP modulations. PM cues elicited prospective positivity and frontal positivity but not N300, perhaps due to the semantic nature of the task. Results of this study revealed an interesting interaction between PM cue frequency and PM cue repetition for prospective positivity and frontal positivity, highlighting the importance of taking both factors into account when designing future studies.

  1. Dual-Comb Coherent Raman Spectroscopy with Lasers of 1-GHz Pulse Repetition Frequency

    CERN Document Server

    Mohler, Kathrin J; Yan, Ming; Hänsch, Theodor W; Picqué, Nathalie

    2016-01-01

    We extend the technique of multiplex coherent Raman spectroscopy with two femtosecond mode-locked lasers to oscillators of a pulse repetition frequency of 1 GHz. We demonstrate spectra of liquids, which span 1100 cm$^{-1}$ of Raman shifts. At a resolution of 6 cm$^{-1}$, their measurement time may be as short as 5 microseconds for a refresh rate of 2 kHz. The waiting period between acquisitions is improved ten-fold compared to previous experiments with two lasers of 100-MHz repetition frequencies.

  2. Low-frequency repetitive transcranial magnetic simulation prevents chronic epileptic seizure*

    Institute of Scientific and Technical Information of China (English)

    Yinxu Wang; Xiaoming Wang; Sha Ke; Juan Tan; Litian Hu; Yaodan Zhang; Wenjuan Cui

    2013-01-01

    Although low-frequency repetitive transcranial magnetic simulation can potentially treat epilepsy, its underlying mechanism remains unclear. This study investigated the influence of low-frequency re-petitive transcranial magnetic simulation on changes in several nonlinear dynamic electroenceph-alographic parameters in rats with chronic epilepsy and explored the mechanism underlying repeti-tive transcranial magnetic simulation-induced antiepileptic effects. An epilepsy model was estab-lished using lithium-pilocarpine intraperitoneal injection into adult Sprague-Dawley rats, which were then treated with repetitive transcranial magnetic simulation for 7 consecutive days. Nonlinear elec-electroencephalographic parameters were obtained from the rats at 7, 14, and 28 days post-stimulation. Results showed significantly lower mean correlation-dimension and Kolmogo-rov-entropy values for stimulated rats than for non-stimulated rats. At 28 days, the complexity and point-wise correlation dimensional values were lower in stimulated rats. Low-frequency repetitive transcranial magnetic simulation has suppressive effects on electrical activity in epileptic rats, thus explaining its effectiveness in treating epilepsy.

  3. Multiple sessions of low-frequency repetitive transcranial magnetic stimulation in focal hand dystonia

    DEFF Research Database (Denmark)

    Kimberley, Teresa Jacobson; Borich, Michael R; Arora, Sanjeev

    2013-01-01

    Purpose: The ability of low-frequency repetitive transcranial magnetic stimulation (rTMS) to enhance intracortical inhibition has motivated its use as a potential therapeutic intervention in focal hand dystonia (FHD). In this preliminary investigation, we assessed the physiologic and behavioral...

  4. The influence of PRF on BER performance of THSS UWB radio system with PPM in dense multipath fading environments

    Institute of Scientific and Technical Information of China (English)

    Jia Lin; Zhang Zhongzhao

    2005-01-01

    The influence of pulse repetition frequency(PRF) on performance of wireless digital time hopping spread spectrum(THSS) ultrawide bandwidth(UWB) radio systems with PPM in dense multipath fading environments is firstly investigated. The receiver used in this UWB system is a hybrid selection/maximal-ratio combining(H-S/MRC) diversity receiver in which L strongest multipath components out of N multipath diversity branches are selected and combined using maximal-ratio combining. The exact expressions for the bit error rate(BER) of this UWB system are firstly derived by using the virtual branch technique in term of PRF, the number of multipath components selected and combined L,and multipath spread of the channel and then this BER performance is evaluated. With the computer simulation for impulses having different pulse shapes, numerical results show that PRF, as well as pulse shape and the number of multipath diversity branches selected and combined L, has much effect on the BER performance of this UWB system in dense multipath fading environments. As PRF increases, the BER performance of this UWB system is much degraded under the conditions of fixed L and pulse shape.

  5. Application of the multiple PRF technique to resolve Doppler centroid estimation ambiguity for spaceborne SAR

    Science.gov (United States)

    Chang, C. Y.; Curlander, J. C.

    1992-01-01

    Estimation of the Doppler centroid ambiguity is a necessary element of the signal processing for SAR systems with large antenna pointing errors. Without proper resolution of the Doppler centroid estimation (DCE) ambiguity, the image quality will be degraded in the system impulse response function and the geometric fidelity. Two techniques for resolution of DCE ambiguity for the spaceborne SAR are presented; they include a brief review of the range cross-correlation technique and presentation of a new technique using multiple pulse repetition frequencies (PRFs). For SAR systems, where other performance factors control selection of the PRF's, an algorithm is devised to resolve the ambiguity that uses PRF's of arbitrary numerical values. The performance of this multiple PRF technique is analyzed based on a statistical error model. An example is presented that demonstrates for the Shuttle Imaging Radar-C (SIR-C) C-band SAR, the probability of correct ambiguity resolution is higher than 95 percent for antenna attitude errors as large as 3 deg.

  6. [Treatment of vascular Parkinson's syndrome after stroke by ultralow frequency and high frequency repetitive transcranial magnetic stimulation].

    Science.gov (United States)

    Xie, Renming; Li, Yanru; Lei, Da

    2015-04-01

    To determine effect and safety of ultra-low frequency and high frequency repetitive transcranial magnetic stimulation on treating vascular Parkinson's syndrome (VPS) after stroke. The 0.1 Hz low frequency (n=21) and 5 Hz high frequency (n=21) rTMS were used to treat patients with VPS, and the false stimulation servered as a control group (n=18). The UPDRS score and Parkinson's Disease Questionnaire (PDQ) were chosen to evaluate the curative effect on PD. The patients were given anti-PD drugs continuously during the treatment. UPDRS scores as well as I, II, and III scores after the treatment were significantly decreased in both the ultra-low frequency group and the high frequency group compared with those before the treatment (all Pfrequency and the high frequency group at the same time point before and after the treatment (P>0.05). There was no significant difference in UPDRS scores between before and after the treatment in the control group (P>0.05), but PDQ scores were significantly decreased at the third month after the treatment compared with those of before and after treatment (Pfrequency and high frequency repetitive transcranial magnetic stimulation can safely improve the clinical symptoms and life quality of patients with VPS.

  7. Study on the mode-transition of nanosecond-pulsed dielectric barrier discharge between uniform and filamentary by controlling pressures and pulse repetition frequencies

    Science.gov (United States)

    Yu, Sizhe; Lu, Xinpei

    2016-09-01

    We investigate the temporally resolved evolution of the nanosecond pulsed dielectric barrier discharge (DBD) in a moderate 6mm gap under various pressures and pulse repetition frequencies (PRFs) by intensified charge-coupled device (ICCD) images, using synthetic air and its components oxygen and nitrogen. It is found that the pressures are very different when the DBD mode transits between uniform and filamentary in air, oxygen, and nitrogen. The PRFs can also obviously affect the mode-transition. The transition mechanism in the pulsed DBD is not Townsend-to-streamer, which is dominant in the traditional alternating-voltage DBDs. The pulsed DBD in a uniform mode develops in the form of plane ionization wave, due to overlap of primary avalanches, while the increase in pressure disturbs the overlap and DBD develops in streamer instead, corresponding to the filamentary mode. Increasing the initiatory electron density by pre-ionization methods may contribute to discharge uniformity at higher pressures. We also find that the dependence of uniformity upon PRF is non-monotonic.

  8. Study on the mode-transition of nanosecond-pulsed dielectric barrier discharge between uniform and filamentary by controlling pressures and pulse repetition frequencies

    Science.gov (United States)

    Yu, S.; Pei, X.; Hasnain, Q.; Nie, L.; Lu, X.

    2016-02-01

    In this paper, we investigate the temporally resolved evolution of the nanosecond pulsed dielectric barrier discharge (DBD) in a moderate 6 mm discharge gap under various pressures and pulse repetition frequencies (PRFs) by intensified charge-coupled device (ICCD) images, using dry air and its components oxygen and nitrogen. It is found that the pressures are very different when the mode transits between uniform and filamentary in air, oxygen, and nitrogen. The PRFs can also obviously affect the mode-transition. The transition mechanism in the pulsed DBD is not Townsend-to-Streamer, which is dominant in the traditional alternating-voltage DBD. The pulsed DBD in a uniform mode develops in the form of plane ionization wave due to overlap of primary avalanches, while the increase in pressure disturbs the overlap and discharge develops in streamer, corresponding to the filamentary mode. Increasing the initial electron density by pre-ionization may contribute to discharge uniformity at higher pressures. We also found that the dependence of homogeneity upon PRF is a non-monotonic one.

  9. Impact of visual repetition rate on intrinsic properties of low frequency fluctuations in the visual network.

    Directory of Open Access Journals (Sweden)

    Yi-Chia Li

    Full Text Available BACKGROUND: Visual processing network is one of the functional networks which have been reliably identified to consistently exist in human resting brains. In our work, we focused on this network and investigated the intrinsic properties of low frequency (0.01-0.08 Hz fluctuations (LFFs during changes of visual stimuli. There were two main questions to be discussed in this study: intrinsic properties of LFFs regarding (1 interactions between visual stimuli and resting-state; (2 impact of repetition rate of visual stimuli. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed scanning sessions that contained rest and visual stimuli in various repetition rates with a novel method. The method included three numerical approaches involving ICA (Independent Component Analyses, fALFF (fractional Amplitude of Low Frequency Fluctuation, and Coherence, to respectively investigate the modulations of visual network pattern, low frequency fluctuation power, and interregional functional connectivity during changes of visual stimuli. We discovered when resting-state was replaced by visual stimuli, more areas were involved in visual processing, and both stronger low frequency fluctuations and higher interregional functional connectivity occurred in visual network. With changes of visual repetition rate, the number of areas which were involved in visual processing, low frequency fluctuation power, and interregional functional connectivity in this network were also modulated. CONCLUSIONS/SIGNIFICANCE: To combine the results of prior literatures and our discoveries, intrinsic properties of LFFs in visual network are altered not only by modulations of endogenous factors (eye-open or eye-closed condition; alcohol administration and disordered behaviors (early blind, but also exogenous sensory stimuli (visual stimuli with various repetition rates. It demonstrates that the intrinsic properties of LFFs are valuable to represent physiological states of human brains.

  10. Frequency and amplitude characteristics of a high-repetition-rate hybrid TEA-CO/sub 2/ laser

    Energy Technology Data Exchange (ETDEWEB)

    Lachambre, J.L.; Lavigne, P.; Verreault, M.; Otis, G.

    1978-02-01

    The envelope and frequency characteristics of the output pulse of a high-repetition-rate hybrid TEA-CO/sub 2/ laser are presented. Both the intrapulse and interpulse laser frequency stability are experimentally determined at repetition rates up to 300 Hz. The recovery of the CW laser signal following the generation of the TEA laser pulse is analyzed theoretically and experimentally. Short term reproducibilities of + or - 2 MHz are observed at a pulse repetition rate of 300 Hz with initial chirp rates of about 1.5 MHz/microsec. Improvements and limits on power and repetition rate are discussed.

  11. High average power coherent vuv generation at 10 MHz repetition frequency by intracavity high harmonic generation.

    Science.gov (United States)

    Ozawa, Akira; Zhao, Zhigang; Kuwata-Gonokami, Makoto; Kobayashi, Yohei

    2015-06-15

    Intracavity high harmonic generation was utilized to generate high average-power coherent radiation at vacuum ultraviolet (vuv) wavelengths. A ytterbium-doped fiber-laser based master-oscillator power-amplifier (MOPA) system with a 10 MHz repetition frequency was developed and used as a driving laser for an external cavity. A series of odd-order harmonic radiations was generated extending down to ∼ 30 nm (41 eV in photon energy). The 7th harmonic radiation generated was centered at 149 nm and had an average output power of up to 0.5 mW. In this way, we developed a sub-mW coherent vuv-laser with a 10 MHz repetition frequency, which, if used as an excitation laser source for photo-electron spectroscopy, could improve the signal count-rate without deterioration of the spectral-resolution caused by space-charge effects.

  12. Optically pumped terahertz lasers with high pulse repetition frequency: theory and design

    Institute of Scientific and Technical Information of China (English)

    Yude Sun; Shiyou Fu; Jing Wang; Zhenghe Sun; Yanchao Zhang; Zhaoshuo Tian; Qi Wang

    2009-01-01

    Optically pumped terahertz (THz) lasers with high pulse repetition frequency are designed. Such a laser includes two parts: the optically pumping laser and the THz laser. The structures of the laser are described and analyzed. The rate equations for the pulsed THz laser are given. The kinetic process and laser pulse waveform for this kind of laser are numerically calculated based on the theory of rate equations. The theoretical results give a helpful guide to the research of such lasers.

  13. Acousto-optic pulse picking scheme with carrier-frequency-to-pulse-repetition-rate synchronization.

    Science.gov (United States)

    de Vries, Oliver; Saule, Tobias; Plötner, Marco; Lücking, Fabian; Eidam, Tino; Hoffmann, Armin; Klenke, Arno; Hädrich, Steffen; Limpert, Jens; Holzberger, Simon; Schreiber, Thomas; Eberhardt, Ramona; Pupeza, Ioachim; Tünnermann, Andreas

    2015-07-27

    We introduce and experimentally validate a pulse picking technique based on a travelling-wave-type acousto-optic modulator (AOM) having the AOM carrier frequency synchronized to the repetition rate of the original pulse train. As a consequence, the phase noise characteristic of the original pulse train is largely preserved, rendering this technique suitable for applications requiring carrier-envelope phase stabilization. In a proof-of-principle experiment, the 1030-nm spectral part of an 74-MHz, carrier-envelope phase stable Ti:sapphire oscillator is amplified and reduced in pulse repetition frequency by a factor of two, maintaining an unprecedentedly low carrier-envelope phase noise spectral density of below 68 mrad. Furthermore, a comparative analysis reveals that the pulse-picking-induced additional amplitude noise is minimized, when the AOM is operated under synchronicity. The proposed scheme is particularly suitable when the down-picked repetition rate is still in the multi-MHz-range, where Pockels cells cannot be applied due to piezoelectric ringing.

  14. Scheme for independently stabilizing the repetition rate and optical frequency of a laser using a regenerative mode-locking technique.

    Science.gov (United States)

    Nakazawa, Masataka; Yoshida, Masato

    2008-05-15

    We have succeeded in achieving independent control of the repetition rate and optical frequency of a pulse laser by employing a regenerative mode-locking technique. By adopting a voltage-controlled microwave phase shifter or an optical delay line in a regenerative feedback loop we can control the repetition rate of the laser without directly disturbing the optical frequencies. We experimentally show how this independent control can be realized by employing a 40 GHz harmonically and regeneratively mode-locked fiber laser.

  15. Repetition rate multiplication of frequency comb using all-pass fiber resonator

    Science.gov (United States)

    Yang, Lijun; Yang, Honglei; Zhang, Hongyuan; Wei, Haoyun; Li, Yan

    2016-09-01

    We propose a stable method for repetition rate multiplication of a 250-MHz Er-fiber frequency comb by a phase-locked all-pass fiber ring resonator, whose phase-locking configuration is simple. The optical path length of the fiber ring resonator is automatically controlled to be accurately an odd multiple of half of the original cavity length using an electronical phase-locking unit with an optical delay line. As for shorter cavity length of the comb, high-order odd multiple is preferable. Because the power loss depends only on the net-attenuation of the fiber ring resonator, the energetic efficiency of the proposed method is high. The input and output optical spectrums show that the spectral width of the frequency comb is clearly preserved. Besides, experimental results show less pulse intensity fluctuation and 35 dB suppression ratio of side-modes while providing a good long-term and short-term frequency stability. Higher-order repetition rate multiplication to several GHz can be obtained by using several fiber ring resonators in cascade configuration.

  16. Repetitive transcranial magnetic stimulation decreases the kindling induced synaptic potentiation: effects of frequency and coil shape.

    Science.gov (United States)

    Yadollahpour, Ali; Firouzabadi, Seyed Mohammad; Shahpari, Marzieh; Mirnajafi-Zadeh, Javad

    2014-02-01

    The present study was aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on kindling-induced synaptic potentiation and to study the effect of frequency and coil shape on rTMS effectiveness. Seizures were induced in rats by perforant path stimulation in a rapid kindling manner (12 stimulations/day). rTMS was applied at different frequencies (0.5, 1 and 2 Hz), using either figure-8 shaped or circular coils at different times (during or before kindling stimulations). rTMS had antiepileptogenic effect at all frequencies and imposed inhibitory effects on enhancement of population excitatory postsynaptic potential slope and population spike amplitude when applied during kindling acquisition. Furthermore, it prevented the kindling-induced changes in paired pulse indices. The inhibitory effect of rTMS was higher at the frequency of 1 Hz compared to 0.5 and 2 Hz. Application of rTMS 1Hz by circular coil imposed a weaker inhibitory action compared with the figure-8 coil. In addition, the results showed that pretreatment of animals by both coils had similar preventing effect on kindling acquisition as well as kindling-induced synaptic potentiation. Obtained results demonstrated that the antiepileptogenic effect of low frequency rTMS is accompanied with the preventing of the kindling induced potentiation. This effect is dependent on rTMS frequency and slightly on coil-type.

  17. Study of synthetic aperture lidar imaging with lower pulse repeti-tion frequency%低脉冲重复频率合成孔径激光雷达成像

    Institute of Scientific and Technical Information of China (English)

    郭亮; 曾晓东; 邢孟道; 唐禹

    2011-01-01

    为提高合成孔径激光雷达(SAL)的分辨率,从激光脉冲调制与脉冲重复频率(PRF)的矛盾入手,提出了一种沿方位向放置多个望远镜接收的系统设计方法,利用空间自南度解决由于较低PRF带来的方位模糊问题.分析了SAL系统由于平台连续运动的影响(表现为多普勒频移项),提出了多普勒平移补偿方法.通过仿真实验验证了本文所提系统设计的正确性,和所给方法的有效性,有效地解决了方位模糊问题.%Synthetic aperture lidar (SAL) is a new active imaging system, which can offer a finer azimuth resolution than conventional SAR systems. The concept of equivalent phase center was described After analysis of the conflict between the modulation of laser signal and pulse repetition frequency (PRF) of the lidar system, which leads to the ambiguity of the Doppler domain in the azimuth direction,a proper system was given,which uses a series of telescopes placed in the azimuth direction. This system makes use of information of the space domain,and removes the ambiguity of the frequency domain in the azimuth direction. The motion during the transmission of a sweep and the reception of the corresponding echo induce a Doppler shift. And then,a method compensating the Doppler shift iwa given. The simulation results show the validity of the given system and method, which can remove the ambiguity.

  18. Compact, high-repetition-rate source for broadband sum-frequency generation spectroscopy

    Science.gov (United States)

    Heiner, Zsuzsanna; Petrov, Valentin; Mero, Mark

    2017-06-01

    We present a high-efficiency optical parametric source for broadband vibrational sum-frequency generation (BB-VSFG) for the chemically important mid-infrared spectral range at 2800-3600 cm-1 to study hydrogen bonding interactions affecting the structural organization of biomolecules at water interfaces. The source consists of a supercontinuum-seeded, dual-beam optical parametric amplifier with two broadband infrared output beams and a chirped sum-frequency mixing stage providing narrowband visible pulses with adjustable bandwidth. Utilizing a pulse energy of only 60 μJ from a turn-key, 1.03-μm pump laser operating at a repetition rate of 100 kHz, the source delivers 6-cycle infrared pulses at 1.5 and 3.2 μm with pulse energies of 4.6 and 1.8 μJ, respectively, and narrowband pulses at 0.515 μm with a pulse energy of 5.0 μJ. The 3.2-μm pulses are passively carrier envelope phase stabilized with fluctuations at the 180-mrad level over a 10-s time period. The 1.5-μm beamline can be exploited to deliver pump pulses for time-resolved studies after suitable frequency up-conversion. The high efficiency, stability, and two orders of magnitude higher repetition rate of the source compared to typically employed systems offer great potential for providing a boost in sensitivity in BB-VSFG experiments at a reduced cost.

  19. Repetitive cleaning of a stainless steel first mirror using radio frequency plasma

    Science.gov (United States)

    Peng, Jiao; Yan, Rong; Ding, Rui; Chen, Junling; Zhu, Dahuan; Zhang, Zengming

    2017-10-01

    First mirrors (FMs) are crucial components of optical diagnostic systems in present-day tokamaks and future fusion reactors. Their lifetimes should be extremely limited due to their proximity to burning plasma, greatly influencing the safe operation of corresponding diagnostics. Repetitive cleaning is expected to provide a solution to the frequent replacement of contaminated FMs, thus prolonging their lifetimes. Three repetitive cleaning cycles using radio frequency plasma were applied to stainless steel (SS) FM samples, to evaluate the change of the mirrors’ optical properties and morphology during each cycle. Amorphous carbon films were deposited on mirror surfaces under identical conditions in three cycles. In three cycles with identical cleaning parameters, the total reflectivity was restored at up to 95%. Nevertheless, with successive cleaning cycles, the FM surfaces gradually appeared to roughen due to damage to the grain boundaries. Correspondingly, the diffuse reflectivity increased from a few percent to 20% and 27% after the second and third cycles. After optimizing the cleaning parameters of the second and third cycles, the roughness showed a significant decrease, and simultaneously the increase of diffuse reflectivity was remarkably improved.

  20. Pulsed radiofrequency -PRF- on the dorsal root ganglion (La radiofrequenza pulsata (PRF gangliare

    Directory of Open Access Journals (Sweden)

    Carmelo Costa

    2014-06-01

    Full Text Available Radiofrequency is a high frequency electric alternating current. The therapeutic effects of radiofrequency (related to a thermal lesion of nervous targets have been used for many years for pain syndromes not responsive to pharmacological therapies. The mechanism of antalgic action is a through an electrode. The disadvantages of this method have always been correlated to limited use for sensitive nerve structures (nerve damage. In the mid-‘90s, a new method (PRF treated a nervous structure with a non-damaging temperature, above 44°C. To verify the efficacy of PRF when applied to dorsal root ganglia, (according to evidence based medicine the authors selected literature from several studies of chronic pain syndrome. Through a specific testing score, it is possible to select chronic pain syndromes with a positive response to the treatment. In summary, we see a large problem with the insufficient refund.

  1. Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300

    Science.gov (United States)

    Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji

    2012-04-01

    The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.

  2. Fetal Heart Rate Monitoring from Phonocardiograph Signal Using Repetition Frequency of Heart Sounds

    Directory of Open Access Journals (Sweden)

    Hong Tang

    2016-01-01

    Full Text Available As a passive, harmless, and low-cost diagnosis tool, fetal heart rate (FHR monitoring based on fetal phonocardiography (fPCG signal is alternative to ultrasonographic cardiotocography. Previous fPCG-based methods commonly relied on the time difference of detected heart sound bursts. However, the performance is unavoidable to degrade due to missed heart sounds in very low signal-to-noise ratio environments. This paper proposes a FHR monitoring method using repetition frequency of heart sounds. The proposed method can track time-varying heart rate without both heart sound burst identification and denoising. The average accuracy rate comparison to benchmark is 88.3% as the SNR ranges from −4.4 dB to −26.7 dB.

  3. Bottle microresonator broadband and low-repetition-rate frequency comb generator.

    Science.gov (United States)

    Dvoyrin, V; Sumetsky, M

    2016-12-01

    We propose a new type of broadband and low repetition rate (RR) frequency comb generator that has the shape of an elongated and nanoscale-shallow optical bottle microresonator created at the surface of an optical fiber. The free spectral range (FSR) of the broadband azimuthal eigenfrequency series of this resonator is the exact multiple of the FSR of the dense and narrowband axial series. The effective radius variation of the microresonator is close to a parabola with a nanoscale height that is greater or equal to λ/2πn0. (Here λ is the characteristic radiation wavelength and n0 is the refractive index of the microresonator material.) Overall, the microresonator possesses a broadband, small FSR and accurately equidistant spectrum convenient for the generation of a broadband and low RR optical frequency comb. It is shown that this comb can be generated by pumping with a cw laser, with a radiation frequency that matches a single axial eigenfrequency of the microresonator or, alternatively, by pumping with a mode-locked laser, which generates a narrowband low RR comb matching a series of equidistant axial eigenfrequencies situated between adjacent azimuthal eigenfrequencies.

  4. Active mode locking at 50 GHz repetition frequency by half-frequency modulation of monolithic semiconductor lasers integrated with electroabsorption modulators

    Science.gov (United States)

    Sato, Kenji; Kotaka, Isamu; Kondo, Yasuhiro; Yamamoto, Mitsuo

    1996-10-01

    Active mode locking achieved at a 50 GHz repetition frequency by modulation at half (25 GHz) the cavity resonance frequency using a monolithic mode-locked InGaAsP laser integrated with an electroabsorption modulator is described. A pulse width of around 3 ps and a high suppression ratio of more than 33 dB of the intensity modulation at the driving frequency are obtained.

  5. Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Paul A Muller

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP, presumably reflecting long-term depression (LTD -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1 reproduce cortico-spinal depression by LF rTMS in rats, (2 establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3 test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR, by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered.

  6. Slow frequency repetitive transcranial magnetic stimulation affects reaction times, but not priming effects, in a masked prime task

    NARCIS (Netherlands)

    Schlaghecken, F.; Munchau, A.; Bloem, B.R.; Rothwell, J.C.; Eimer, M.

    2003-01-01

    OBJECTIVE: Slow frequency repetitive transcranial magnetic stimulation (rTMS) reduces motor cortex excitability, but it is unclear whether this has behavioural consequences in healthy subjects. METHODS: We examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 80% of active motor thr

  7. Reweighted ℓ1 referenceless PRF shift thermometry.

    Science.gov (United States)

    Grissom, William A; Lustig, Michael; Holbrook, Andrew B; Rieke, Viola; Pauly, John M; Butts-Pauly, Kim

    2010-10-01

    Temperature estimation in proton resonance frequency (PRF) shift MR thermometry requires a reference, or pretreatment, phase image that is subtracted from image phase during thermal treatment to yield a phase difference image proportional to temperature change. Referenceless thermometry methods derive a reference phase image from the treatment image itself by assuming that in the absence of a hot spot, the image phase can be accurately represented in a smooth (usually low order polynomial) basis. By masking the hot spot out of a least squares (ℓ(2)) regression, the reference phase image's coefficients on the polynomial basis are estimated and a reference image is derived by evaluating the polynomial inside the hot spot area. Referenceless methods are therefore insensitive to motion and bulk main field shifts, however, currently these methods require user interaction or sophisticated tracking to ensure that the hot spot is masked out of the polynomial regression. This article introduces an approach to reference PRF shift thermometry that uses reweighted ℓ(1) regression, a form of robust regression, to obtain background phase coefficients without hot spot tracking and masking. The method is compared to conventional referenceless thermometry, and demonstrated experimentally in monitoring HIFU heating in a phantom and canine prostate, as well as in a healthy human liver.

  8. Priming theta-burst repetitive transcranial magnetic stimulation with low- and high-frequency stimulation.

    Science.gov (United States)

    Todd, Gabrielle; Flavel, Stanley C; Ridding, Michael C

    2009-05-01

    Repetitive transcranial magnetic stimulation (rTMS) can be used to study metaplasticity in human motor cortex. The term metaplasticity describes a phenomenon where the prior synaptic history of a pathway can affect the subsequent induction of long-term potentiation or depression. In the current study, we investigated metaplasticity in human motor cortex with the use of inhibitory continuous theta-burst stimulation (cTBS). cTBS involves short bursts of high frequency (50 Hz) rTMS applied every 200 ms for 40 s. In the first series of experiments, cTBS was primed with 10 min of intermittent 2 or 6 Hz rTMS. Subjects (n = 20) received priming stimulation at 70% of active motor threshold or 90% of resting motor threshold. In another series of experiments, cTBS was primed with excitatory intermittent theta-burst stimulation (iTBS). iTBS involves a 2 s train of theta-burst stimulation delivered every 10 s for 190 s. Stimuli were delivered over the first dorsal interosseus motor area.. The effect of cTBS alone and primed cTBS on motor cortical excitability was investigated by recording motor-evoked potentials (MEP) in the first dorsal interosseus following single-pulse TMS. MEP area in the cTBS alone condition was not significantly different from cTBS primed with 2 or 6 Hz rTMS. However, priming cTBS with iTBS suppressed MEP area to a greater extent than in cTBS alone. Our results provide further evidence of metaplasticity in human motor cortex when appropriate priming protocols are employed.

  9. The benefit of repetitive skills training and frequency of expert feedback in the early acquisition of procedural skills.

    Science.gov (United States)

    Bosse, Hans Martin; Mohr, Jonathan; Buss, Beate; Krautter, Markus; Weyrich, Peter; Herzog, Wolfgang; Jünger, Jana; Nikendei, Christoph

    2015-02-19

    Redundant training and feedback are crucial for successful acquisition of skills in simulation trainings. It is still unclear how or how much feedback should best be delivered to maximize its effect, and how learners' activity and feedback are optimally blended. To determine the influence of high- versus low-frequency expert feedback on the learning curve of students' clinical procedural skill acquisition in a prospective randomized study. N = 47 medical students were trained to insert a nasogastric tube in a mannequin, including structured feedback in the initial instruction phase at the beginning of the training (T1), and either additional repetitive feedback after each of their five subsequent repetitions (high-frequency feedback group, HFF group; N = 23) or additional feedback on just one occasion, after the fifth repetition only (low-frequency feedback group, LFF group; N = 24). We assessed a) task-specific clinical skill performance and b) global procedural performance (five items of the Integrated Procedural Performance Instrument (IPPI); on the basis of expert-rated videotapes at the beginning of the training (T1) and during the final, sixth trial (T2). The two study groups did not differ regarding their baseline data. The calculated ANOVA for task-specific clinical skill performance with the between-subject factor 'Group' (HFF vs. LFF) and within-subject factors 'Time' (T1 vs. T2) turned out not to be significant (p training (T2; p training (T2; p training.

  10. Efficient intracavity frequency doubling of a high-repetition-rate diode-pumped Nd:YAG laser.

    Science.gov (United States)

    Hanson, F; Poirier, P

    1994-10-01

    Efficient operation of a pulsed, high-repetition-rate diode-pumped and intracavity frequency-doubled Nd:YAG laser is reported. A 3-mm-diameter laser rod was side-pumped with a 5-bar stack of high-duty-cycle 1-cm diodearrays. The average Q-switched power at 1.06microum was 3.8 W at 1.33 kH(z), and more than 4 W at 0.532 ,microm wasobtained through intracavity frequency doubling with LiB(3)O(5).

  11. Prolonged Analgesic Effect of PRF-108 and PRF-110 on Post-operative Pain in Pigs.

    Science.gov (United States)

    Castel, David; Naveh, Michael; Aharon, Arnon; Doron, Ofer; Meilin, Sigal

    2016-06-01

    Local anesthetic infusion techniques have been reported to reduce opiate requirements and pain scores following different kinds of surgery, including orthopedic surgery, inguinal hernia, and Cesarean surgery in women. PRF-108 and PRF-110 formulations were applied to the wound space in an incisional model in pigs to test the hypothesis that these formulations have better and longer analgesic effects than the commercially available ropivacaine solution (Naropin(®), AstraZeneca). The data show significantly better analgesic activity with PRF-108 and PRF-110 compared to ropivacaine. The duration of the analgesic efficacy of PRF-108 and PRF-110 was at least five times longer than that was measured following treatment with ropivacaine. The data further suggest that active clearance from the injection site (the wound) is much slower for PRF-108 and PRF-110 than for the commercial ropivacaine solution. Assessing the local concentration of PRF compounds and commercially available ropivacaine solution suggests that active clearance from the injection site (the wound) is much slower for PRF-108 and PRF-110 than for ropivacaine. PainReform.

  12. Dual-frequency comb generation with differing GHz repetition rates by parallel Fabry-Perot cavity filtering of a single broadband frequency comb source

    Science.gov (United States)

    Mildner, Jutta; Meiners-Hagen, Karl; Pollinger, Florian

    2016-07-01

    We present a dual-comb-generator based on a coupled Fabry-Perot filtering cavity doublet and a single seed laser source. By filtering a commercial erbium-doped fiber-based optical frequency comb with CEO-stabilisation and 250 MHz repetition rate, two broadband coherent combs of different repetition rates in the GHz range are generated. The filtering doublet consists of two Fabry-Perot cavities with a tunable spacing and Pound-Drever-Hall stabilisation scheme. As a prerequisite for the development of such a filtering unit, we present a method to determine the actual free spectral range and transmission bandwidth of a Fabry-Perot cavity in situ. The transmitted beat signal of two diode lasers is measured as a function of their tunable frequency difference. Finally, the filtering performance and resulting beat signals of the heterodyned combs are discussed as well as the optimisation measures of the whole system.

  13. PRF

    African Journals Online (AJOL)

    GB

    MANAGEMENT OF GRADE-II FURCATION DEFECT ... teeth offer unique and challenging problems due to the furcation area, ... On clinical and radiographic ... Figure 1: (a) 9 mm loss of horizontal clinical attachment when measure with ...

  14. Arabidopsis Profilin Isoforms, PRF1 and PRF2Show Distinctive Binding Activities and Subcellular Distributions

    Institute of Scientific and Technical Information of China (English)

    Feng Wang; Yanping Jing; Zhen Wang; Tonglin Mao; Jozef (S)amaj; Ming Yuan; Haiyun Ren

    2009-01-01

    Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fluorescent protein (GFP) tag and expressed in Escherichia coli and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgsnic A. thaliana lines revealed that 35S::GFP-PRF1 formed a filamentous network, while 35S::GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profllin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive Iocalizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.

  15. High Repetition Rate and Frequency Stabilized Ho:YLF Laser for CO2 Differential Absorption Lidar

    Science.gov (United States)

    Bai, Yingxin; Yu, Jirong; Petros, M.; Petzar, Pau; Trieu, Bo; Lee, Hyung; Singh, U.

    2009-01-01

    High repetition rate operation of an injection seeded Ho:YLF laser has been demonstrated. For 1 kHz operation, the output pulse energy reaches 5.8mJ and the optical-to-optical efficiency is 39% when the pump power is 14.5W.

  16. SGT1 interacts with the Prf resistance protein and is required for Prf accumulation and Prf-mediated defense signaling.

    Science.gov (United States)

    Kud, Joanna; Zhao, Zhulu; Du, Xinran; Liu, Yule; Zhao, Yun; Xiao, Fangming

    2013-02-15

    The highly conserved eukaryotic co-chaperone SGT1 (suppressor of the G2 allele of skp1) is an important signaling component of plant defense responses and positively regulates disease resistance conferred by many resistance (R) proteins. In this study, we investigated the contribution of SGT1 in the Prf-mediated defense responses in both Nicotiana benthamiana and tomato (Solanum lycopersicum). SGT1 was demonstrated to interact with Prf in plant cells by co-immunoprecipitation. The requirement of SGT1 in the accumulation of Prf or autoactive Prf(D1416V) was determined by the degradation of these proteins in N. benthamiana, in which SGT1 was repressed by virus-induced gene silencing (VIGS). Pseudomonas pathogen assay on the SGT1-silenced tomato plants implicates SGT1 is required for the Prf-mediated full resistance to Pseudomonas syringae pv. tomato (Pst). These results suggest that, in both N. benthamiana and tomato, SGT1 contributes to the Prf-mediated defense responses by stabilizing Prf protein via its co-chaperone activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Monolithic all-fiber repetition-rate tunable gain-switched single-frequency Yb-doped fiber laser.

    Science.gov (United States)

    Hou, Yubin; Zhang, Qian; Qi, Shuxian; Feng, Xian; Wang, Pu

    2016-12-12

    We report a monolithic gain-switched single-frequency Yb-doped fiber laser with widely tunable repetition rate. The single-frequency laser operation is realized by using an Yb-doped distributed Bragg reflection (DBR) fiber cavity, which is pumped by a commercial-available laser diode (LD) at 974 nm. The LD is electronically modulated by the driving current and the diode output contains both continuous wave (CW) and pulsed components. The CW component is set just below the threshold of the single-frequency fiber laser for reducing the requirement of the pump pulse energy. Above the threshold, the gain-switched oscillation is trigged by the pulsed component of the diode. Single-frequency pulsed laser output is achieved at 1.063 μm with a pulse duration of ~150 ns and a linewidth of 14 MHz. The repetition rate of the laser output can be tuned between 10 kHz and 400 kHz by tuning the electronic trigger signal. This kind of lasers shows potential for the applications in the area of coherent LIDAR etc.

  18. High-Temporal-Resolution High-Spatial-Resolution Spaceborne SAR Based on Continuously Varying PRF.

    Science.gov (United States)

    Men, Zhirong; Wang, Pengbo; Li, Chunsheng; Chen, Jie; Liu, Wei; Fang, Yue

    2017-07-25

    Synthetic Aperture Radar (SAR) is a well-established and powerful imaging technique for acquiring high-spatial-resolution images of the Earth's surface. With the development of beam steering techniques, sliding spotlight and staring spotlight modes have been employed to support high-spatial-resolution applications. In addition to this strengthened high-spatial-resolution and wide-swath capability, high-temporal-resolution (short repeat-observation interval) represents a key capability for numerous applications. However, conventional SAR systems are limited in that the same patch can only be illuminated for several seconds within a single pass. This paper considers a novel high-squint-angle system intended to acquire high-spatial-resolution spaceborne SAR images with repeat-observation intervals varying from tens of seconds to several minutes within a single pass. However, an exponentially increased range cell migration would arise and lead to a conflict between the receive window and 'blind ranges'. An efficient data acquisition technique for high-temporal-resolution, high-spatial-resolution and high-squint-angle spaceborne SAR, in which the pulse repetition frequency (PRF) is continuously varied according to the changing slant range, is presented in this paper. This technique allows echo data to remain in the receive window instead of conflicting with the transmitted pulse or nadir echo. Considering the precision of hardware, a compromise and practical strategy is also proposed. Furthermore, a detailed performance analysis of range ambiguities is provided with respect to parameters of TerraSAR-X. For strong point-like targets, the range ambiguity of this technique would be better than that of uniform PRF technique. For this innovative technique, a resampling strategy and modified imaging algorithm have been developed to handle the non-uniformly sampled echo data. Simulations are performed to validate the efficiency of the proposed technique and the associated

  19. Stability of repetitive-sequence PCR patterns with respect to culture age and subculture frequency.

    Science.gov (United States)

    Kang, Hyunseok Peter; Dunne, W Michael

    2003-06-01

    To examine the stability of repetitive-sequence (rep) PCR profiles, six species of bacteria were subcultured to blood agar plates and DNA was extracted from the cultures after 24, 48, and 72 h of incubation at 35 degrees C. In addition, the same species were subcultured to fresh blood plates daily and DNA was extracted from the cultures after growth of 5, 10, and 15 subcultures, respectively. rep PCR analysis demonstrated that all rep PCR fingerprints from a single species were identical.

  20. Broadly wavelength- and pulse width-tunable high-repetition rate light pulses from soliton self-frequency shifting photonic crystal fiber integrated with a frequency doubling crystal.

    Science.gov (United States)

    Lanin, Aleksandr A; Fedotov, Andrei B; Zheltikov, Aleksei M

    2012-09-01

    Soliton self-frequency shift (SSFS) in a photonic crystal fiber (PCF) pumped by a long-cavity mode-locked Cr:forsterite laser is integrated with second harmonic generation (SHG) in a nonlinear crystal to generate ultrashort light pulses tunable within the range of wavelengths from 680 to 1800 nm at a repetition rate of 20 MHz. The pulse width of the second harmonic output is tuned from 70 to 600 fs by varying the thickness of the nonlinear crystal, beam-focusing geometry, and the wavelength of the soliton PCF output. Wavelength-tunable pulses generated through a combination of SSFS and SHG are ideally suited for coherent Raman microspectroscopy at high repetition rates, as verified by experiments on synthetic diamond and polystyrene films.

  1. Comparative release of growth factors from PRP, PRF, and advanced-PRF.

    Science.gov (United States)

    Kobayashi, Eizaburo; Flückiger, Laura; Fujioka-Kobayashi, Masako; Sawada, Kosaku; Sculean, Anton; Schaller, Benoit; Miron, Richard J

    2016-12-01

    The use of platelet concentrates has gained increasing awareness in recent years for regenerative procedures in modern dentistry. The aim of the present study was to compare growth factor release over time from platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and a modernized protocol for PRF, advanced-PRF (A-PRF). Eighteen blood samples were collected from six donors (3 samples each for PRP, PRF, and A-PRF). Following preparation, samples were incubated in a plate shaker and assessed for growth factor release at 15 min, 60 min, 8 h, 1 day, 3 days, and 10 days. Thereafter, growth factor release of PDGF-AA, PDGF-AB, PDGF-BB, TGFB1, VEGF, EGF, and IGF was quantified using ELISA. The highest reported growth factor released from platelet concentrates was PDGF-AA followed by PDGF-BB, TGFB1, VEGF, and PDGF-AB. In general, following 15-60 min incubation, PRP released significantly higher growth factors when compared to PRF and A-PRF. At later time points up to 10 days, it was routinely found that A-PRF released the highest total growth factors. Furthermore, A-PRF released significantly higher total protein accumulated over a 10-day period when compared to PRP or PRF. The results from the present study indicate that the various platelet concentrates have quite different release kinetics. The advantage of PRP is the release of significantly higher proteins at earlier time points whereas PRF displayed a continual and steady release of growth factors over a 10-day period. Furthermore, in general, it was observed that the new formulation of PRF (A-PRF) released significantly higher total quantities of growth factors when compared to traditional PRF. Based on these findings, PRP can be recommended for fast delivery of growth factors whereas A-PRF is better-suited for long-term release.

  2. High resolution characterization of modifications in fused silica after exposure to low fluence 355 nm laser at different repetition frequencies.

    Science.gov (United States)

    Li, C H; Ju, X; Jiang, X D; Huang, J; Zhou, X D; Zheng, Z; Wu, W D; Zheng, W G; Li, Z X; Wang, B Y; Yu, X H

    2011-03-28

    We report on the characterization of modifications in fused silica after exposure to low fluence (2 J/cm2) 355 nm laser at repetition frequencies of 1 Hz, 5 Hz and 10 Hz. Synchrotron based XRF spectroscopy is employed to study concentration variation of metal inclusions in the surface layer. Positron annihilation lifetime spectroscopy is used to probe atomic size defects variation in bulk silica. FT-IR is used to characterize changes of bond length and angle of Si-O-Si covalent bond of irradiated silica. Compared to the basic frequency, the big loss of cerium and iron concentration, the size enlargement of vacancy cluster and the decrease of Si-O-Si covalent bond length after 10 Hz laser irradiation are illustrated by our data. These tiny modifications provide important data to investigate laser damage mechanism.

  3. Laser-induced retinal damage threshold for repetitive-pulse exposure to 100-microsecs pulses

    Science.gov (United States)

    2014-10-07

    and is inde pendent of the pulse repetition frequency (PRF). When the injury mechanism is thermal denaturation, the pulses do interact , with the peak...energy incident on the cornea that passes through the pupil of the eye. TIE is expressed in this paper as the energy per pulse in the pulse train. 3...given in the guidelines as the corneal irradiance (J∕cm2), was multi plied by the area of a 7 mm pupil to give the allowable TIE. CP is a multiplicative

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

    Science.gov (United States)

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

    2016-03-01

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

  5. Phantom Limb Pain: Low Frequency Repetitive Transcranial Magnetic Stimulation in Unaffected Hemisphere

    Directory of Open Access Journals (Sweden)

    Andrea Di Rollo

    2011-01-01

    Full Text Available Phantom limb pain is very common after limb amputation and is often difficult to treat. The motor cortex stimulation is a valid treatment for deafferentation pain that does not respond to conventional pain treatment, with relief for 50% to 70% of patients. This treatment is invasive as it uses implanted epidural electrodes. Cortical stimulation can be performed noninvasively by repetitive transcranial magnetic stimulation (rTMS. The stimulation of the hemisphere that isn't involved in phantom limb (unaffected hemisphere, remains unexplored. We report a case of phantom limb pain treated with 1 Hz rTMS stimulation over motor cortex in unaffected hemisphere. This stimulation produces a relevant clinical improvement of phantom limb pain; however, further studies are necessary to determine the efficacy of the method and the stimulation parameters.

  6. Features of the repetition frequency of edge localized modes in EAST

    DEFF Research Database (Denmark)

    Jiang, M.; Xiao, C.; Xu, G.S.;

    2012-01-01

    (LHW) heating power on the EAST tokamak. The ELMs in EAST are Type III ELMs with high frequency (several hundred Hertz) and low amplitude. ELM features for the following two types of EAST discharges are investigated: discharges with only LHW and those with both LHW and ion cyclotron resonance frequency...

  7. High Energy Single Frequency Fiber Laser at Low Repetition Rate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  8. Preliminary Evidence of the Effects of High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Swallowing Functions in Post-Stroke Individuals with Chronic Dysphagia

    Science.gov (United States)

    Cheng, Ivy K. Y.; Chan, Karen M. K.; Wong, C. S.; Cheung, Raymond T. F.

    2015-01-01

    Background: There is growing evidence of potential benefits of repetitive transcranial magnetic stimulation (rTMS) in the rehabilitation of dysphagia. However, the site and frequency of stimulation for optimal effects are not clear. Aims: The aim of this pilot study is to investigate the short-term effects of high-frequency 5 Hz rTMS applied to…

  9. Preliminary Evidence of the Effects of High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Swallowing Functions in Post-Stroke Individuals with Chronic Dysphagia

    Science.gov (United States)

    Cheng, Ivy K. Y.; Chan, Karen M. K.; Wong, C. S.; Cheung, Raymond T. F.

    2015-01-01

    Background: There is growing evidence of potential benefits of repetitive transcranial magnetic stimulation (rTMS) in the rehabilitation of dysphagia. However, the site and frequency of stimulation for optimal effects are not clear. Aims: The aim of this pilot study is to investigate the short-term effects of high-frequency 5 Hz rTMS applied to…

  10. Effects of low- and high-frequency repetitive magnetic stimulation on neuronal cell proliferation and growth factor expression: A preliminary report.

    Science.gov (United States)

    Lee, Ji Yong; Park, Hyung Joong; Kim, Ji Hyun; Cho, Byung Pil; Cho, Sung-Rae; Kim, Sung Hoon

    2015-09-14

    Repetitive magnetic stimulation is a neuropsychiatric and neurorehabilitation tool that can be used to investigate the neurobiology of sensory and motor functions. Few studies have examined the effects of repetitive magnetic stimulation on the modulation of neurotrophic/growth factors and neuronal cells in vitro. Therefore, the current study examined the differential effects of repetitive magnetic stimulation on neuronal cell proliferation as well as various growth factor expression. Immortalized mouse neuroblastoma cells were used as the cell model in this study. Dishes of cultured cells were randomly divided into control, sham, low-frequency (0.5Hz, 1Tesla) and high-frequency (10Hz, 1Tesla) groups (n=4 dishes/group) and were stimulated for 3 days. Expression of neurotrophic/growth factors, Akt and Erk was investigated by Western blotting analysis 3 days after repetitive magnetic stimulation. Neuroblastoma cell proliferation was determined with a cell counting assay. There were differences in cell proliferation based on stimulus frequency. Low-frequency stimulation did not alter proliferation relative to the control, while high-frequency stimulation elevated proliferation relative to the control group. The expression levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NT-3) and platelet-derived growth factor (PDGF) were elevated in the high-frequency magnetic stimulation group. Akt and Erk expression was also significantly elevated in the high-frequency stimulation group, while low-frequency stimulation decreased the expression of Akt and Erk compared to the control. In conclusion, we determined that different frequency magnetic stimulation had an influence on neuronal cell proliferation via regulation of Akt and ERK signaling pathways and the expression of growth factors such as BDNF, GDNF, NT-3 and PDGF. These findings represent a promising opportunity to gain insight into how different

  11. Cortical excitability changes after high-frequency repetitive transcranial magnetic stimulation for central poststroke pain.

    Science.gov (United States)

    Hosomi, Koichi; Kishima, Haruhiko; Oshino, Satoru; Hirata, Masayuki; Tani, Naoki; Maruo, Tomoyuki; Yorifuji, Shiro; Yoshimine, Toshiki; Saitoh, Youichi

    2013-08-01

    Central poststroke pain (CPSP) is one of the most refractory chronic pain syndromes. Repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex has been demonstrated to provide moderate pain relief for CPSP. However, the mechanism underlying the pain relief remains unclear. The objective of this study was to assess changes in cortical excitability in patients with intractable CPSP before and after rTMS of the primary motor cortex. Subjects were 21 patients with CPSP of the hand who underwent rTMS. The resting motor threshold, the amplitude of the motor evoked potential, duration of the cortical silent period, short interval intracortical inhibition, and intracortical facilitation were measured as parameters of cortical excitability before and after navigation-guided 5 Hz rTMS of the primary motor cortex corresponding to the painful hand. Pain reduction from rTMS was assessed with a visual analog scale. The same parameters were measured in both hemispheres of 8 healthy controls. Eight of 21 patients experienced ≥ 30% pain reduction after rTMS (responders). The resting motor threshold in the patients was higher than those in the controls at baseline (P=.035). Intracortical facilitation in the responders was lower than in the controls and the nonresponders at baseline (P=.035 and P=.019), and significantly increased after rTMS (P=.039). There were no significant differences or changes in the other parameters. Our findings suggest that restoration of abnormal cortical excitability might be one of the mechanisms underlying pain relief as a result of rTMS in CPSP.

  12. A model of reverse spike frequency adaptation and repetitive firing of subthalamic nucleus neurons.

    Science.gov (United States)

    Wilson, Charles J; Weyrick, Angela; Terman, David; Hallworth, Nicholas E; Bevan, Mark D

    2004-05-01

    Subthalamic nucleus neurons exhibit reverse spike-frequency adaptation. This occurs only at firing rates of 20-50 spikes/s and higher. Over this same frequency range, there is an increase in the steady-state frequency-intensity (F-I) curve's slope (the secondary range). Specific blockade of high-voltage activated calcium currents reduced the F-I curve slope and reverse adaptation. Blockade of calcium-dependent potassium current enhanced secondary range firing. A simple model that exhibited these properties used spike-triggered conductances similar to those in subthalamic neurons. It showed: 1) Nonaccumulating spike afterhyperpolarizations produce positively accelerating F-I curves and spike-frequency adaptation that is complete after the second spike. 2) Combinations of accumulating aftercurrents result in a linear F-I curve, whose slope depends on the relative contributions of inward and outward currents. Spike-frequency adaptation can be gradual. 3) With both accumulating and nonaccumulating aftercurrents, primary and secondary ranges will be present in the F-I curve. The slope of the primary range is determined by the nonaccumulating conductance; the accumulating conductances govern the secondary range. The transition is determined by the relative strengths of accumulating and nonaccumulating currents. 4) Spike-threshold accommodation contributes to the secondary range, reducing its slope at high firing rates. Threshold accommodation can stabilize firing when inward aftercurrents exceed outward ones. 5) Steady-state reverse adaptation results when accumulated inward aftercurrents exceed outward ones. This requires spike-threshold accommodation. Transient speedup arises when inward currents are smaller than outward ones at steady state, but accumulate more rapidly. 6) The same mechanisms alter firing in response to irregular patterns of synaptic conductances, as cell excitability fluctuates with changes in firing rate.

  13. High PRF high current switch

    Science.gov (United States)

    Moran, Stuart L.; Hutcherson, R. Kenneth

    1990-03-27

    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  14. Dependence of a rabbit's reaction on the frequency of repetition of an impulse and current exposition in experiment

    Directory of Open Access Journals (Sweden)

    Koklin А.Е.

    2013-12-01

    Full Text Available Now electroshock devices are used as a civilian weapon for self-defense and as a non-lethal weapon in the police. Therefore, medical-biological safety testing of electroshock devices should be carried out. Development of hygienic regulations is relevant as well. The aim of our work is the study of the biological effects of pulsed current depending on the pulse frequency, pulse amplitude and exposure. Material and methods. We compared the biological effects with varying frequency of the current pulse (50, 400, and 600 Hz with varying exposure (0.25, 0.5 and 1.0 s.. Average pulse power in all cases was equal, and the pulse energy was different. Experiments were performed on rabbits. Biological effects of stun device were evaluated by clinical lesions, as well as electrophysiological parameters: ECG and electro-pneumogram. Results. Response was observed only in the current period (0.25 s, 0.5 s or 1 s was disorientation, convulsing, dyspnea. The degree of severity of the reaction was determined by a combination of pulse repetition frequency and exposure. Immediately after switching off the current noted vocalization, decreased heart rate and breathing. Heart rate and respiration in 5 minutes back to the normal values. Conclusions. In the results of the research has got a comparative classification organism's response (based on a points system as well as the characteristic of the biological response of the individual systems of the body on the parameters of the current pulse.

  15. Effect of low-frequency repetitive transcranial magnetic stimulation combined with physical therapy on L-dopa-induced painful off-period dystonia in Parkinson's disease.

    Science.gov (United States)

    Kodama, Mitsuhiko; Kasahara, Takashi; Hyodo, Masaki; Aono, Koji; Sugaya, Mutsumi; Koyama, Yuji; Hanayama, Kozo; Masakado, Yoshihisa

    2011-02-01

    Previous research has shown that low-frequency repetitive transcranial magnetic stimulation over the primary motor area and supplementary motor area can reduce L-dopa-induced dyskinesias in Parkinson's disease; however, it involved only patients with peak-dose or diphasic dyskinesia. We report a case of a patient with severely painful off-period dystonia in the unilateral lower limb who underwent 0.9-Hz subthreshold repetitive transcranial magnetic stimulation over contralateral primary motor area and supplementary motor area. Repetitive transcranial magnetic stimulation over the primary motor area significantly reduced the painful dystonia and walking disturbances but repetitive transcranial magnetic stimulation over the supplementary motor area did not. The cortical silent period also prolonged after repetitive transcranial magnetic stimulation over the primary motor area. At 5 mos of approximately once a week repetitive transcranial magnetic stimulation over the primary motor area, the Unified Parkinson's Disease Rating Scale motor score also improved. This report shows that repetitive transcranial magnetic stimulation over the inhibitory primary motor area can be useful for rehabilitating patients with Parkinson's disease with off-period dystonia and suggests that this treatment should be further verified in such patients.

  16. Copper bromide vapor brightness amplifiers with 100 kHz pulse repetition frequency

    Science.gov (United States)

    Trigub, M. V.; Evtushenko, G. S.; Torgaev, S. N.; Shiyanov, D. V.; Evtushenko, T. G.

    2016-10-01

    The paper presents a laser monitor with 10 μs time-resolution based on a high-frequency copper bromide vapor brightness amplifier. A sync circuit has been designed for single-pulse imaging. The analysis of amplifying characteristics of the active elements and active optical system (laser monitor) parameters allowed to determine the optimal concentration of HBr at which the images can be obtained with minimum distortions. For the active element operating at high frequencies (more than 50 kHz) as a brightness amplifier, the concentration of HBr must be lower than that needed for obtaining the maximum output power. The limiting brightness temperature of the background radiation which does not affect the image quality is determined. The potential feasibility of using a proposed brightness amplifier for visualizing processes blocked from viewing by the background radiation with the brightness temperature up to 8000 K is demonstrated.

  17. Myeloid dendritic cells frequencies are increased in children with autism spectrum disorder and associated with amygdala volume and repetitive behaviors.

    Science.gov (United States)

    Breece, Elizabeth; Paciotti, Brian; Nordahl, Christine Wu; Ozonoff, Sally; Van de Water, Judy A; Rogers, Sally J; Amaral, David; Ashwood, Paul

    2013-07-01

    The pathophysiology of autism spectrum disorder (ASD) is not yet known; however, studies suggest that dysfunction of the immune system affects many children with ASD. Increasing evidence points to dysfunction of the innate immune system including activation of microglia and perivascular macrophages, increases in inflammatory cytokines/chemokines in brain tissue and CSF, and abnormal peripheral monocyte cell function. Dendritic cells are major players in innate immunity and have important functions in the phagocytosis of pathogens or debris, antigen presentation, activation of naïve T cells, induction of tolerance and cytokine/chemokine production. In this study, we assessed circulating frequencies of myeloid dendritic cells (defined as Lin-1(-)BDCA1(+)CD11c(+) and Lin-1(-)BDCA3(+)CD123(-)) and plasmacytoid dendritic cells (Lin-1(-)BDCA2(+)CD123(+) or Lin-1(-)BDCA4(+) CD11c(-)) in 57 children with ASD, and 29 typically developing controls of the same age, all of who were enrolled as part of the Autism Phenome Project (APP). The frequencies of dendritic cells and associations with behavioral assessment and MRI measurements of amygdala volume were compared in the same participants. The frequencies of myeloid dendritic cells were significantly increased in children with ASD compared to typically developing controls (pfrequencies of myeloid dendritic cells were positively associated with abnormal right and left amygdala enlargement, severity of gastrointestinal symptoms and increased repetitive behaviors. The frequencies of plasmacytoid dendritic cells were also associated with amygdala volumes as well as developmental regression in children with ASD. Dendritic cells play key roles in modulating immune responses and differences in frequencies or functions of these cells may result in immune dysfunction in children with ASD. These data further implicate innate immune cells in the complex pathophysiology of ASD.

  18. Pain Control on Demand Based on Pulsed Radio-Frequency Stimulation of the Dorsal Root Ganglion Using a Batteryless Implantable CMOS SoC.

    Science.gov (United States)

    Hung-Wei Chiu; Mu-Lien Lin; Chii-Wann Lin; I-Hsiu Ho; Wei-Tso Lin; Po-Hsiang Fang; Yi-Chin Lee; Yeong-Ray Wen; Shey-Shi Lu

    2010-12-01

    This paper presents the implementation of a batteryless CMOS SoC with low voltage pulsed radio-frequency (PRF) stimulation. This implantable SoC uses 402 MHz command signals following the medical implanted communication system (MICS) standard and a low frequency (1 MHz) for RF power transmission. A body floating type rectifier achieves 84% voltage conversion ratio. A bi-phasic pulse train of 1.4 V and 500 kHz is delivered by a PRF driver circuit. The PRF parameters include pulse duration, pulse frequency and repetition rate, which are controllable via 402 MHz RF receiver. The minimal required 3 V RF Vin and 2.2 V VDDr is achieved at 18 mm gap. The SoC chip is fabricated in a 0.35 μm CMOS process and mounted on a PCB with a flexible spiral antenna. The packaged PRF SoC was implanted into rats for the animal study. Von Frey was applied to test the mechanical allodynia in a blinded manner. This work has successfully demonstrated that implanted CMOS SoC stimulating DRG with 1.4 V, 500 kHz PRF could significantly reduce spinal nerve ligation (SNL) induced mechanical allodynia for 3-7 days.

  19. Modulation of the Left Prefrontal Cortex with High Frequency Repetitive Transcranial Magnetic Stimulation Facilitates Gait in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Amer M. Burhan

    2015-01-01

    Full Text Available Multiple Sclerosis (MS is a chronic central nervous system (CNS demyelinating disease. Gait abnormalities are common and disabling in patients with MS with limited treatment options available. Emerging evidence suggests a role of prefrontal attention networks in modulating gait. High-frequency repetitive transcranial magnetic stimulation (rTMS is known to enhance cortical excitability in stimulated cortex and its correlates. We investigated the effect of high-frequency left prefrontal rTMS on gait parameters in a 51-year-old Caucasian male with chronic relapsing/remitting MS with residual disabling attention and gait symptoms. Patient received 6 Hz, rTMS at 90% motor threshold using figure of eight coil centered on F3 location (using 10-20 electroencephalography (EEG lead localization system. GAITRite gait analysis system was used to collect objective gait measures before and after one session and in another occasion three consecutive daily sessions of rTMS. Two-tailed within subject repeated measure t-test showed significant enhancement in ambulation time, gait velocity, and cadence after three consecutive daily sessions of rTMS. Modulating left prefrontal cortex excitability using rTMS resulted in significant change in gait parameters after three sessions. To our knowledge, this is the first report that demonstrates the effect of rTMS applied to the prefrontal cortex on gait in MS patients.

  20. Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex

    Science.gov (United States)

    Mesquita, Rickson C.; Faseyitan, Olufunsho K.; Turkeltaub, Peter E.; Buckley, Erin M.; Thomas, Amy; Kim, Meeri N.; Durduran, Turgut; Greenberg, Joel H.; Detre, John A.; Yodh, Arjun G.; Hamilton, Roy H.

    2013-06-01

    Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects.

  1. A self-reference PRF-shift MR thermometry method utilizing the phase gradient.

    Science.gov (United States)

    Langley, Jason; Potter, William; Phipps, Corey; Huang, Feng; Zhao, Qun

    2011-12-21

    In magnetic resonance (MR) imaging, the most widely used and accurate method for measuring temperature is based on the shift in proton resonance frequency (PRF). However, inter-scan motion and bulk magnetic field shifts can lead to inaccurate temperature measurements in the PRF-shift MR thermometry method. The self-reference PRF-shift MR thermometry method was introduced to overcome such problems by deriving a reference image from the heated or treated image, and approximates the reference phase map with low-order polynomial functions. In this note, a new approach is presented to calculate the baseline phase map in self-reference PRF-shift MR thermometry. The proposed method utilizes the phase gradient to remove the phase unwrapping step inherent to other self-reference PRF-shift MR thermometry methods. The performance of the proposed method was evaluated using numerical simulations with temperature distributions following a two-dimensional Gaussian function as well as phantom and in vivo experimental data sets. The results from both the numerical simulations and experimental data show that the proposed method is a promising technique for measuring temperature.

  2. A Fast Polar Format Algorithm Based on Variable PRF for Bistatic SAR%一种变 PRF 双基 SAR 快速极坐标格式算法

    Institute of Scientific and Technical Information of China (English)

    丁晶; 李盘虎; 毛新华

    2016-01-01

    极坐标格式算法(PFA)是双基聚束模式合成孔径雷达(SAR)成像中一种经典的成像算法,在聚束 SAR 系统中有着重要的意义。从信号二维解耦合的角度出发,进一步分析极坐标格式算法中距离向插值和方位向插值对目标距离徙动(RCM)的校正过程,给出了对双基 SAR 极坐标格式算法的一种新解释,并提出一种基于变脉冲重复频率(PRF)的双基 SAR 快速极坐标格式算法。该方法可以提高双基 SAR 极坐标格式算法的计算效率,扩大其应用范围。点目标仿真验证了该方法的有效性。%Polar format algorithm (PFA)is a classic algorithm for bistatic synthetic aperture radar (SAR)imaging and has important significance in spotlight bistatic SAR system.In this paper,we analyze the range and azimuth resampling procedures for their roles in range cell migration(RCM)correction from the viewpoint of two-dimensional decoupling and provide a new formulation of PFA for bistatic spotlight SAR.A fast polar format algorithm is proposed,which is based on variable pulse repetition frequency (PRF).This algorithm can improve the computation efficiency and expand the application range of PFA for bistatic SAR imaging.Point target simulation validates the algorithm.

  3. Pulsed radiofrequency -PRF- on the dorsal root ganglion (La radiofrequenza pulsata (PRF) gangliare)

    National Research Council Canada - National Science Library

    Carmelo Costa; Elisabetta Sanalitro

    2014-01-01

    .... The mechanism of antalgic action is a through an electrode. The disadvantages of this method have always been correlated to limited use for sensitive nerve structures (nerve damage). In the mid-‘90s, a new method (PRF...

  4. End-pumped all solid-state high repetition rate Tm, Ho:LuLF laser

    Institute of Scientific and Technical Information of China (English)

    Shijiang Shu; Ting Yu; Junyan Hou; Rongtao Liu; Minjie Huang; Weibiao Chen

    2011-01-01

    @@ The characteristics of diode end-pumped Tm,Ho:LuLiF for continuous wave (CW) running and high pulse repetition frequency (PRF) Q-switched operation are illustrated. In the CW mode, 950-mW output power with a slope efficiency of 24% is obtained. In the Q-switched mode, output energy of 78 μJ under 10 kHz with a slope efficiency of 23% is achieved. The pulse stability, pulse width as a function of pump intensity, and spectral characteristics are also analyzed.%The characteristics of diode end-pumped Tm,Ho:LuLiF for continuous wave (CW) running and high pulse repetition frequency (PRF) Q-switched operation are illustrated. In the CW mode, 950-mW output power with a slope efficiency of 24% is obtained. In the Q-switched mode, output energy of 78μJ under 10 kHz with a slope efficiency of 23% is achieved. The pulse stability, pulse width as a function of pump intensity, and spectral characteristics are also analyzed.

  5. Prolonged Analgesic Effect of PRF-108 and PRF-110 on Post-operative Pain in Pigs

    OpenAIRE

    Castel, David; Naveh, Michael; Aharon, Arnon; Doron, Ofer; Meilin,Sigal

    2016-01-01

    Introduction Local anesthetic infusion techniques have been reported to reduce opiate requirements and pain scores following different kinds of surgery, including orthopedic surgery, inguinal hernia, and Cesarean surgery in women. Methods PRF-108 and PRF-110 formulations were applied to the wound space in an incisional model in pigs to test the hypothesis that these formulations have better and longer analgesic effects than the commercially available ropivacaine solution (Naropin®, AstraZenec...

  6. Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Poststroke Patients with Upper Limb Hemiparesis: Preliminary Study of a 15-Day Protocol

    Science.gov (United States)

    Kakuda, Wataru; Abo, Masahiro; Kobayashi, Kazushige; Momosaki, Ryo; Yokoi, Aki; Fukuda, Akiko; Ishikawa, Atsushi; Ito, Hiroshi; Tominaga, Ayumi

    2010-01-01

    The purpose of the study was to determine the safety and feasibility of a 15-day protocol of low-frequency repetitive transcranial magnetic stimulation (rTMS) combined with intensive occupational therapy (OT) on motor function and spasticity in hemiparetic upper limbs in poststroke patients. Fifteen poststroke patients (age at study entry 55 [plus…

  7. A high pulse repetition frequency ultrasound system for the ex vivo measurement of mechanical properties of crystalline lenses with laser-induced microbubbles interrogated by acoustic radiation force.

    Science.gov (United States)

    Yoon, Sangpil; Aglyamov, Salavat; Karpiouk, Andrei; Emelianov, Stanislav

    2012-08-07

    A high pulse repetition frequency ultrasound system for an ex vivo measurement of mechanical properties of an animal crystalline lens was developed and validated. We measured the bulk displacement of laser-induced microbubbles created at different positions within the lens using nanosecond laser pulses. An impulsive acoustic radiation force was applied to the microbubble, and spatio-temporal measurements of the microbubble displacement were assessed using a custom-made high pulse repetition frequency ultrasound system consisting of two 25 MHz focused ultrasound transducers. One of these transducers was used to emit a train of ultrasound pulses and another transducer was used to receive the ultrasound echoes reflected from the microbubble. The developed system was operating at 1 MHz pulse repetition frequency. Based on the measured motion of the microbubble, Young's moduli of surrounding tissue were reconstructed and the values were compared with those measured using the indentation test. Measured values of Young's moduli of four bovine lenses ranged from 2.6 ± 0.1 to 26 ± 1.4 kPa, and there was good agreement between the two methods. Therefore, our studies, utilizing the high pulse repetition frequency ultrasound system, suggest that the developed approach can be used to assess the mechanical properties of ex vivo crystalline lenses. Furthermore, the potential of the presented approach for in vivo measurements is discussed.

  8. Bystander Effect Induced by Electroporation is Possibly Mediated by Microvesicles and Dependent on Pulse Amplitude, Repetition Frequency and Cell Type.

    Science.gov (United States)

    Prevc, Ajda; Bedina Zavec, Apolonija; Cemazar, Maja; Kloboves-Prevodnik, Veronika; Stimac, Monika; Todorovic, Vesna; Strojan, Primoz; Sersa, Gregor

    2016-10-01

    Bystander effect, a known phenomenon in radiation biology, where irradiated cells release signals which cause damage to nearby, unirradiated cells, has not been explored in electroporated cells yet. Therefore, our aim was to determine whether bystander effect is present in electroporated melanoma cells in vitro, by determining viability of non-electroporated cells exposed to medium from electroporated cells and by the release of microvesicles as potential indicators of the bystander effect. Here, we demonstrated that electroporation of cells induces bystander effect: Cells exposed to electric pulses mediated their damage to the non-electroporated cells, thus decreasing cell viability. We have shown that shedding microvesicles may be one of the ways used by the cells to mediate the death signals to the neighboring cells. The murine melanoma B16F1 cell line was found to be more electrosensitive and thus more prone to bystander effect than the canine melanoma CMeC-1 cell line. In B16F1 cell line, bystander effect was present above the level of electropermeabilization of the cells, with the threshold at 800 V/cm. Furthermore, with increasing electric field intensities and the number of pulses, the bystander effect also increased. In conclusion, electroporation can induce bystander effect which may be mediated by microvesicles, and depends on pulse amplitude, repetition frequency and cell type.

  9. Word recognition and nonword repetition in children with language disorders: the effects of neighborhood density, lexical frequency, and phonotactic probability.

    Science.gov (United States)

    Rispens, Judith; Baker, Anne; Duinmeijer, Iris

    2015-02-01

    The effects of neighborhood density (ND) and lexical frequency on word recognition and the effects of phonotactic probability (PP) on nonword repetition (NWR) were examined to gain insight into processing at the lexical and sublexical levels in typically developing (TD) children and children with developmental language problems. Tasks measuring NWR and word recognition were administered to 5 groups of children: 2 groups of TD children (5 and 8 years old), children with specific language impairment (SLI), children with reading impairment (RI), and children with SLI+RI (all 7-8 years old). High ND had a negative effect on word recognition in the older TD children and in the children with RI only. There was no ND effect in the younger children or in the children with SLI, who all had lower receptive vocabulary scores than the age-matched TD children and the RI groups. For all groups, NWR items with low PP were more difficult to repeat than items with high PP. This effect was especially pronounced in children with RI. Both the stage of vocabulary development and the type of language impairment (SLI or RI) impact the way ND and PP affect word recognition and NWR.

  10. Modulation of N400 in chronic non-fluent aphasia using low frequency Repetitive Transcranial Magnetic Stimulation (rTMS).

    Science.gov (United States)

    Barwood, Caroline H S; Murdoch, Bruce E; Whelan, Brooke-Mai; Lloyd, David; Riek, Stephan; O'Sullivan, John D; Coulthard, Alan; Wong, Andrew

    2011-03-01

    Low frequency Repetitive Transcranial Magnetic Stimulation (rTMS) has previously been applied to language homologues in non-fluent populations of persons with aphasia yielding significant improvements in behavioral language function up to 43 months post stimulation. The present study aimed to investigate the electrophysiological correlates associated with the application of rTMS through measurement of the semantic based N400 Event-related brain potentials (ERP) component. Low frequency (1 Hz) rTMS was applied to the anterior portion of the homologue to Broca's area (pars triangularis), for 20 min per day for 10 days, using a stereotactic neuronavigational system. Twelve non-fluent persons with aphasia, 2-6 years post stroke were stimulated. Six participants were randomly assigned to receive real stimulation and six participants were randomly assigned to receive a blind sham control condition. ERP measures were recorded at baseline, 1 week and 2 months subsequent to stimulation. The findings demonstrate treatment related changes observed in the stimulation group when compared to the placebo control group at 2 months post stimulation indicating neuromodulation of N400 as a result of rTMS. No treatment related changes were identified in the stimulation group, when compared to the sham group from baseline to 1 week post stimulation. The electrophysiological results represent the capacity of rTMS to modulate neural language networks and measures of lexical-semantic function in participants with non-fluent aphasia and suggest that time may be an important factor in brain reorganization subsequent to rTMS.

  11. Distinct changes in cortical and spinal excitability following high-frequency repetitive TMS to the human motor cortex.

    Science.gov (United States)

    Quartarone, Angelo; Bagnato, Sergio; Rizzo, Vincenzo; Morgante, Francesca; Sant'angelo, Antonio; Battaglia, Fortunato; Messina, Corrado; Siebner, Hartwig Roman; Girlanda, Paolo

    2005-02-01

    It has been shown that high-frequency repetitive transcranial magnetic stimulation (rTMS) to the human primary motor hand area (M1-HAND) can induce a lasting increase in corticospinal excitability. Here we recorded motor evoked potentials (MEPs) from the right first dorsal interosseus muscle to investigate how sub-threshold high-frequency rTMS to the M1-HAND modulates cortical and spinal excitability. In a first experiment, we gave 1500 stimuli of 5 Hz rTMS. At an intensity of 90% of active motor threshold, rTMS produced no effect on MEP amplitude at rest. Increasing the intensity to 90% of resting motor threshold (RMT), rTMS produced an increase in MEP amplitude. This facilitatory effect gradually built up during the course of rTMS, reaching significance after the administration of 900 stimuli. In a second experiment, MEPs were elicited during tonic contraction using weak anodal electrical or magnetic test stimuli. 1500 (but not 600) conditioning stimuli at 90% of RMT induced a facilitation of MEPs in the contracting FDI muscle. In a third experiment, 600 conditioning stimuli were given at 90% of RMT to the M1-HAND. Using two well-established conditioning-test paradigms, we found a decrease in short-latency intracortical inhibition (SICI), and a facilitation of the first peak of facilitatory I-waves interaction (SICF). There was no correlation between the relative changes in SICI and SICF. These results demonstrate that subthreshold 5 Hz rTMS can induce lasting changes in specific neuronal subpopulations in the human corticospinal motor system, depending on the intensity and duration of rTMS. Short 5 Hz rTMS (600 stimuli) at 90% of RMT can selectively shape the excitability of distinct intracortical circuits, whereas prolonged 5 Hz rTMS (> or =900 stimuli) provokes an overall increase in excitability of the corticospinal output system, including spinal motoneurones.

  12. Regulation of tomato Prf by Pto-like protein kinases.

    Science.gov (United States)

    Mucyn, Tatiana S; Wu, Ai-Jiuan; Balmuth, Alexi L; Arasteh, Julia Maryam; Rathjen, John P

    2009-04-01

    Tomato Prf encodes a nucleotide-binding domain shared by Apaf-1, certain R proteins, and CED-4 fused to C-terminal leucine-rich repeats (NBARC-LRR) protein that is required for bacterial immunity to Pseudomonas syringae and sensitivity to the organophosphate fenthion. The signaling pathways involve two highly related protein kinases. Pto kinase mediates direct recognition of the bacterial effector proteins AvrPto or AvrPtoB. Fen kinase is required for fenthion sensitivity and recognition of bacterial effectors related to AvrPtoB. The role of Pto and its association with Prf has been characterized but Fen is poorly described. We show that, similar to Pto, Fen requires N-myristoylation and kinase activity for signaling and interacts with the N-terminal domain of Prf. Thus, the mechanisms of activation of Prf by the respective protein kinases are similar. Prf-Fen interaction is underlined by coregulatory mechanisms in which Prf negatively regulates Fen, most likely by controlling kinase activity. We further characterized negative regulation of Prf by Pto, and show that regulation is mediated by the previously described negative regulatory patch. Remarkably, the effectors released negative regulation of Prf in a manner dependent on Pto kinase activity. The data suggest a model in which Prf associates generally with Pto-like kinases in tightly regulated complexes, which are activated by effector-mediated disruption of negative regulation. Release of negative regulation may be a general feature of activation of NBARC-LRR proteins by cognate effectors.

  13. Performance characteristics of an induction linac magnetic pulse compression modulator at multi-kilohertz pulse repetition frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Sampayan, S.E.; Chambers, F.W.; Deadrick, F.J. [and others

    1991-05-01

    The ETA-II linear induction accelerator utilizes four pulse power conditioning chains. Magnetic pulse compression modulators (MAG1-Ds) form the last stage of each chain. A single power conditioning chain is used to drive the injector; the remaining three are used to drive 60 accelerator cells. Nominal parameters of the MAG1-D are an output voltage of greater than 120 kV, pulse width of 70 ns, and an output impedance of 2 ohms. Our operations goal for ETA-II is stable high average power operation at 5 kHz PRF. We have begun upgrading and characterizing the power conditioning chain on our High Average Power Test Stand (HAPTS). On HAPTS, the pulse to pulse amplitude stability has been improved to less than 0.7% (one sigma) and of order 3-5 ns random jitter about a systematic timing variation. In this paper we describe the status of our work to achieve the this paper we describe the status of our work to achieve the average power operation of ETA-II

  14. An estimation of the influence of force decrease on the mean power spectral frequency shift of the EMG during repetitive maximum dynamic knee extensions.

    Science.gov (United States)

    Karlsson, J S; Ostlund, N; Larsson, B; Gerdle, B

    2003-10-01

    Frequency analysis of myoelectric (ME) signals, using the mean power spectral frequency (MNF), has been widely used to characterize peripheral muscle fatigue during isometric contractions assuming constant force. However, during repetitive isokinetic contractions performed with maximum effort, output (force or torque) will decrease markedly during the initial 40-60 contractions, followed by a phase with little or no change. MNF shows a similar pattern. In situations where there exist a significant relationship between MNF and output, part of the decrease in MNF may per se be related to the decrease in force during dynamic contractions. This study estimated force effects on the MNF shifts during repetitive dynamic knee extensions. Twenty healthy volunteers participated in the study and both surface ME signals (from the right vastus lateralis, vastus medialis, and rectus femoris muscles) and the biomechanical signals (force, position, and velocity) of an isokinetic dynamometer were measured. Two tests were performed: (i) 100 repetitive maximum isokinetic contractions of the right knee extensors, and (ii) five gradually increasing static knee extensions before and after (i). The corresponding ME signal time-frequency representations were calculated using the continuous wavelet transform. Compensation of the MNF variables of the repetitive contractions was performed with respect to the individual MNF-force relation based on an average of five gradually increasing contractions. Whether or not compensation was necessary was based on the shape of the MNF-force relationship. A significant compensation of the MNF was found for the repetitive isokinetic contractions. In conclusion, when investigating maximum dynamic contractions, decreases in MNF can be due to mechanisms similar to those found during sustained static contractions (force-independent component of fatigue) and in some subjects due to a direct effect of the change in force (force-dependent component of fatigue

  15. Brain responses evoked by high-frequency repetitive transcranial magnetic stimulation: an event-related potential study

    NARCIS (Netherlands)

    M. Hamidi; H.A. Slagter; G. Tononi; B.R. Postle

    2010-01-01

    Background Many recent studies have used repetitive transcranial magnetic stimulation (rTMS) to study brain-behavior relationships. However, the pulse-to-pulse neural effects of rapid delivery of multiple TMS pulses are unknown largely because of TMS-evoked electrical artifacts limiting recording of

  16. Continuous high PRF waveforms for challenging environments

    Science.gov (United States)

    Jaroszewski, Steven; Corbeil, Allan; Ryland, Robert; Sobota, David

    2017-05-01

    Current airborne radar systems segment the available time-on-target during each beam dwell into multiple Coherent Processing Intervals (CPIs) in order to eliminate range eclipsing, solve for unambiguous range, and increase the detection performance against larger Radar Cross Section (RCS) targets. As a consequence, these radars do not realize the full Signal-to-Noise Ratio (SNR) increase and detection performance improvement that is possible. Continuous High Pulse Repetition Frequency (HPRF) waveforms and processing enables the coherent integration of all available radar data over the full time-on-target. This can greatly increase the SNR for air targets at long range and/or with weak radar returns and significantly improve the detection performance against such targets. TSC worked with its partner KeyW to implement a Continuous HPRF waveform in their Sahara radar testbed and obtained measured radar data on both a ground vehicle target and an airborne target of opportunity. This experimental data was processed by TSC to validate the expected benefits of Continuous HPRF waveforms.

  17. Compact High-Repetition-Rate Monochromatic Terahertz Source Based on Difference Frequency Generation from a Dual-Wavelength Nd:YAG Laser and DAST Crystal

    Science.gov (United States)

    Zhong, Kai; Mei, Jialin; Wang, Maorong; Liu, Pengxiang; Xu, Degang; Wang, Yuye; Shi, Wei; Yao, Jianquan; Teng, Bing; Xiao, Yong

    2017-01-01

    Although high-repetition-rate dual-wavelength Nd:YAG lasers at 1319 and 1338 nm have been realized for quite a long time, we have employed it in generating monochromatic terahertz (THz) wave in this paper for the first time. The dual-wavelength laser was LD-end-pumped and acousto-optically (AO) Q-switched with the output power of watt level operating at different repetition rates from 5.5 to 30 kHz. Using a 0.6-mm-thick organic nonlinear crystal DAST for difference frequency generation (DFG), a compact terahertz source was achieved at 3.28 THz. The maximum average output power was about 0.58 μW obtained at a repetition rate of 5.5 kHz, corresponding to the conversion efficiency of about 6.4 × 10-7. The output power scaling is still feasible with higher pump power and a longer nonlinear DFG crystal. Owing to the compactness of the dual-wavelength laser and the nonlinear crystal, a palm-top terahertz source is expected for portable applications such as imaging and so on.

  18. 1-MW peak power, 574-kHz repetition rate picosecond pulses at 515 nm from a frequency-doubled fiber amplifier

    Science.gov (United States)

    Zou, Feng; Wang, Ziwei; Wang, Zhaokun; Bai, Yang; Li, Qiurui; Zhou, Jun

    2016-11-01

    1-MW peak power picosecond, 574-kHz repetition rate green laser at 515-nm is generated from a frequency-doubled fiber amplifier. 12-ps pulses with 13.9-μJ energy at 515 nm are achieved with a noncritically phase-matched lithium triborate (LBO) crystal through second harmonic generation of a 1030 nm infrared source. The infrared source employs ultra-large-mode-area rod-type photonic crystal fiber (Rod-PCF) for direct picosecond amplification and delivers 20-W 11.6-ps 2.97-MW pulse train with near-diffraction-limited beam quality (M2 = 1.01).

  19. Subharmonic resonant optical excitation of confined acoustic modes in a free-standing semiconductor membrane at GHz frequencies with a high-repetition-rate femtosecond laser.

    Science.gov (United States)

    Bruchhausen, A; Gebs, R; Hudert, F; Issenmann, D; Klatt, G; Bartels, A; Schecker, O; Waitz, R; Erbe, A; Scheer, E; Huntzinger, J-R; Mlayah, A; Dekorsy, T

    2011-02-18

    We propose subharmonic resonant optical excitation with femtosecond lasers as a new method for the characterization of phononic and nanomechanical systems in the gigahertz to terahertz frequency range. This method is applied for the investigation of confined acoustic modes in a free-standing semiconductor membrane. By tuning the repetition rate of a femtosecond laser through a subharmonic of a mechanical resonance we amplify the mechanical amplitude, directly measure the linewidth with megahertz resolution, infer the lifetime of the coherently excited vibrational states, accurately determine the system's quality factor, and determine the amplitude of the mechanical motion with femtometer resolution.

  20. Functional cortical reorganization after low-frequency repetitive transcranial magnetic stimulation plus intensive occupational therapy for upper limb hemiparesis: evaluation by functional magnetic resonance imaging in poststroke patients.

    Science.gov (United States)

    Yamada, Naoki; Kakuda, Wataru; Senoo, Atsushi; Kondo, Takahiro; Mitani, Sugao; Shimizu, Masato; Abo, Masahiro

    2013-08-01

    Low-frequency repetitive transcranial magnetic stimulation of the nonlesional hemisphere combined with occupational therapy significantly improves motor function of the affected upper limb in poststroke hemiparetic patients, but the recovery mechanism remains unclear. To investigate the recovery mechanism using functional magnetic resonance imaging. Forty-seven poststroke hemiparetic patients were hospitalized to receive 12 sessions of 40-min low-frequency repetitive transcranial magnetic stimulation over the nonlesional hemisphere and daily occupational therapy for 15 days. Motor function was evaluated with the Fugl-Meyer Assessment and Wolf Motor Function Test. The functional magnetic resonance imaging with motor tasks was performed at admission and discharge. The laterality index of activated voxel number in Brodmann areas 4 and 6 on functional magnetic resonance imaging was calculated (laterality index range of -1 to +1). Patients were divided into two groups based on functional magnetic resonance imaging findings before the intervention: group 1: patients who showed bilateral activation (n = 27); group 2: patients with unilateral activation (n = 20). Treatment resulted in improvement in Fugl-Meyer Assessment and Wolf Motor Function Test in the two groups (P functional magnetic resonance imaging indicated that our proposed treatment can induce functional cortical reorganization, leading to motor functional recovery of the affected upper limb. Especially, it seems that neural activation in the lesional hemisphere plays an important role in such recovery in poststroke hemiparetic patients. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization.

  1. Plant programmed cell death caused by an autoactive form of Prf is suppressed by co-expression of the Prf LRR domain.

    Science.gov (United States)

    Du, Xinran; Miao, Min; Ma, Xinrong; Liu, Yongsheng; Kuhl, Joseph C; Martin, Gregory B; Xiao, Fangming

    2012-09-01

    In tomato, the NBARC-LRR resistance (R) protein Prf acts in concert with the Pto or Fen kinase to determine immunity against Pseudomonas syringae pv. tomato (Pst). Prf-mediated defense signaling is initiated by the recognition of two sequence-unrelated Pst-secreted effector proteins, AvrPto and AvrPtoB, by tomato Pto or Fen. Prf detects these interactions and activates signaling leading to host defense responses including localized programmed cell death (PCD) that is associated with the arrest of Pst growth. We found that Prf variants with single amino acid substitutions at D1416 in the IHD motif (isoleucine-histidine-aspartic acid) in the NBARC domain cause effector-independent PCD when transiently expressed in leaves of Nicotiana benthamiana, suggesting D1416 plays an important role in activation of Prf. The N-terminal region of Prf (NPrf) and the LRR domain are required for this autoactive Prf cell death signaling but dispensable for accumulation of the Prf(D1416V) protein. Significantly, co-expression of the Prf LRR but not NPrf, with Prf(D1416V), AvrPto/Pto, AvrPtoB/Pto, an autoactive form of Pto (Pto(Y207D)), or Fen completely suppresses PCD. However, the Prf LRR does not interfere with PCD caused by Rpi-blb1(D475V), a distinct R protein-mediated PCD signaling event, or that caused by overexpression of MAPKKKα, a protein acting downstream of Prf. Furthermore, we found the Prf(D1416V) protein is unable to accumulate in plant cells when co-expressed with the Prf LRR domain, likely explaining the cell death suppression. The mechanism for the LRR-induced degradation of Prf(D1416V) is unknown but may involve interference in the intramolecular interactions of Prf or to binding of the unattached LRR to other host proteins that are needed for Prf stability.

  2. Repetition and Translation Shifts

    Directory of Open Access Journals (Sweden)

    Simon Zupan

    2006-06-01

    Full Text Available Repetition manifests itself in different ways and at different levels of the text. The first basic type of repetition involves complete recurrences; in which a particular textual feature repeats in its entirety. The second type involves partial recurrences; in which the second repetition of the same textual feature includes certain modifications to the first occurrence. In the article; repetitive patterns in Edgar Allan Poe’s short story “The Fall of the House of Usher” and its Slovene translation; “Konec Usherjeve hiše”; are compared. The author examines different kinds of repetitive patterns. Repetitions are compared at both the micro- and macrostructural levels. As detailed analyses have shown; considerable microstructural translation shifts occur in certain types of repetitive patterns. Since these are not only occasional; sporadic phenomena; but are of a relatively high frequency; they reduce the translated text’s potential for achieving some of the gothic effects. The macrostructural textual property particularly affected by these shifts is the narrator’s experience as described by the narrative; which suffers a reduction in intensity.

  3. Experimental investigation of dielectric barrier discharge plasma actuators driven by repetitive high-voltage nanosecond pulses with dc or low frequency sinusoidal bias

    Science.gov (United States)

    Opaits, Dmitry F.; Likhanskii, Alexandre V.; Neretti, Gabriele; Zaidi, Sohail; Shneider, Mikhail N.; Miles, Richard B.; Macheret, Sergey O.

    2008-08-01

    Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their matching to the plasma, a numerical code for short pulse calculations with an arbitrary impedance load was developed. A new approach for nonintrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the schlieren technique, burst mode of plasma actuator operation, and two-dimensional numerical fluid modeling. The force and heating rate calculated by a plasma model was used as an input to two-dimensional viscous flow solver to predict the time-dependent dielectric barrier discharge induced flow field. This approach allowed us to restore the entire two-dimensional unsteady plasma induced flow pattern as well as characteristics of the plasma induced force. Both the experiments and computations showed the same vortex flow structures induced by the actuator. Parametric studies of the vortices at different bias voltages, pulse polarities, peak pulse voltages, and pulse repetition rates were conducted experimentally. The significance of charge buildup on the dielectric surface was demonstrated. The charge buildup decreases the effective electric field in the plasma and reduces the plasma actuator performance. The accumulated surface charge can be removed by switching the bias polarity, which leads to a newly proposed voltage waveform consisting of high-voltage nanosecond repetitive pulses superimposed on a high-voltage low frequency sinusoidal voltage. Advantages of the new voltage waveform were demonstrated experimentally.

  4. Plutonium reclamation facility (PRF), building 236-Z layup plan

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON, R.N.

    1999-04-06

    This document reviews each system inside PRF to determine the operation and maintenance requirements necessary to maintain safe and predictable system performance for facility systems needed to remain operational while minimizing the maintenance and surveillance being performed. Also covered are the actions required to place PRF in a safe layup configuration while minimizing hazards and taking into account the need for reactivation of certain equipment when cleanup work commences in the future.

  5. Cortical excitability in patients with focal epilepsy: a study with high frequency repetitive transcranial magnetic stimulation (rTMS

    Directory of Open Access Journals (Sweden)

    Maria Gabriele

    2008-12-01

    Full Text Available Epileptogenesis involves an increase in excitatory synaptic strength in the brain in a manner similar to synaptic potentiation. In the present study we investigated the mechanisms of short-term synaptic potentiation in patients with focal epilepsy by using 5 Hz repetitive transcranial magnetic stimulation (rTMS, a non invasive neurophysiological technique able to investigate the mechanisms of synaptic plasticity in humans. Ten patients with focal idiopathic cortical epilepsy were studied. 5 Hz-rTMS (10 stimuli-trains, 120% of motor threshold, RMT was delivered over the first dorsal interosseus (FDI motor area of both (affected and unaffected hemispheres. Changes in the motor evoked potential (MEP size in the FDI muscle during the trains and the RMT were measured and compared between the hemispheres. 5 Hz-rTMS was also delivered in a group of healthy subjects over both hemispheres. 5 Hz-rTMS in patients elicited a reduced MEP facilitation compared to normal subjects. The reduced MEP amplitude was more evident in the affected hemisphere than in the unaffected hemisphere. RMT in the affected hemisphere was higher than in the unaffected hemisphere and in healthy subjects. Our findings showing a decreased response to 5 Hz-rTMS over the affected hemisphere, differently from the expected results suggest a reduced cortical excitability in epileptic patients. We hypothesize an altered balance between excitatory and inhibitory circuits in epileptic patients under chronic therapy.

  6. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Jagiello, J.; Lipinska, L. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)

    2015-04-07

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (F{sub rep}) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest F{sub rep} was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  7. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Science.gov (United States)

    Sotor, J.; Sobon, G.; Jagiello, J.; Lipinska, L.; Abramski, K. M.

    2015-04-01

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (Frep) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest Frep was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  8. High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) Improves Functional Recovery by Enhancing Neurogenesis and Activating BDNF/TrkB Signaling in Ischemic Rats.

    Science.gov (United States)

    Luo, Jing; Zheng, Haiqing; Zhang, Liying; Zhang, Qingjie; Li, Lili; Pei, Zhong; Hu, Xiquan

    2017-02-20

    Repetitive transcranial magnetic stimulation (rTMS) has rapidly become an attractive therapeutic approach for stroke. However, the mechanisms underlying this remain elusive. This study aimed to investigate whether high-frequency rTMS improves functional recovery mediated by enhanced neurogenesis and activation of brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) pathway and to compare the effect of conventional 20 Hz rTMS and intermittent theta burst stimulation (iTBS) on ischemic rats. Rats after rTMS were sacrificed seven and 14 days after middle cerebral artery occlusion (MCAO), following evaluation of neurological function. Neurogenesis was measured using specific markers: Ki67, Nestin, doublecortin (DCX), NeuN and glial fibrillary acidic protein (GFAP), and the expression levels of BDNF were visualized by Western blotting and RT-PCR analysis. Both high-frequency rTMS methods significantly improved neurological function and reduced infarct volume. Moreover, 20 Hz rTMS and iTBS significantly promoted neurogenesis, shown by an increase of Ki67/DCX, Ki67/Nestin, and Ki67/NeuN-positive cells in the peri-infarct striatum. These beneficial effects were accompanied by elevated protein levels of BDNF and phosphorylated-TrkB. In conclusion, high-frequency rTMS improves functional recovery possibly by enhancing neurogenesis and activating BDNF/TrkB signaling pathway and conventional 20 Hz rTMS is better than iTBS at enhancing neurogenesis in ischemic rats.

  9. High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS Improves Functional Recovery by Enhancing Neurogenesis and Activating BDNF/TrkB Signaling in Ischemic Rats

    Directory of Open Access Journals (Sweden)

    Jing Luo

    2017-02-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS has rapidly become an attractive therapeutic approach for stroke. However, the mechanisms underlying this remain elusive. This study aimed to investigate whether high-frequency rTMS improves functional recovery mediated by enhanced neurogenesis and activation of brain-derived neurotrophic factor (BDNF/tropomyosin-related kinase B (TrkB pathway and to compare the effect of conventional 20 Hz rTMS and intermittent theta burst stimulation (iTBS on ischemic rats. Rats after rTMS were sacrificed seven and 14 days after middle cerebral artery occlusion (MCAO, following evaluation of neurological function. Neurogenesis was measured using specific markers: Ki67, Nestin, doublecortin (DCX, NeuN and glial fibrillary acidic protein (GFAP, and the expression levels of BDNF were visualized by Western blotting and RT-PCR analysis. Both high-frequency rTMS methods significantly improved neurological function and reduced infarct volume. Moreover, 20 Hz rTMS and iTBS significantly promoted neurogenesis, shown by an increase of Ki67/DCX, Ki67/Nestin, and Ki67/NeuN-positive cells in the peri-infarct striatum. These beneficial effects were accompanied by elevated protein levels of BDNF and phosphorylated-TrkB. In conclusion, high-frequency rTMS improves functional recovery possibly by enhancing neurogenesis and activating BDNF/TrkB signaling pathway and conventional 20 Hz rTMS is better than iTBS at enhancing neurogenesis in ischemic rats.

  10. High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) Improves Functional Recovery by Enhancing Neurogenesis and Activating BDNF/TrkB Signaling in Ischemic Rats

    Science.gov (United States)

    Luo, Jing; Zheng, Haiqing; Zhang, Liying; Zhang, Qingjie; Li, Lili; Pei, Zhong; Hu, Xiquan

    2017-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has rapidly become an attractive therapeutic approach for stroke. However, the mechanisms underlying this remain elusive. This study aimed to investigate whether high-frequency rTMS improves functional recovery mediated by enhanced neurogenesis and activation of brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) pathway and to compare the effect of conventional 20 Hz rTMS and intermittent theta burst stimulation (iTBS) on ischemic rats. Rats after rTMS were sacrificed seven and 14 days after middle cerebral artery occlusion (MCAO), following evaluation of neurological function. Neurogenesis was measured using specific markers: Ki67, Nestin, doublecortin (DCX), NeuN and glial fibrillary acidic protein (GFAP), and the expression levels of BDNF were visualized by Western blotting and RT-PCR analysis. Both high-frequency rTMS methods significantly improved neurological function and reduced infarct volume. Moreover, 20 Hz rTMS and iTBS significantly promoted neurogenesis, shown by an increase of Ki67/DCX, Ki67/Nestin, and Ki67/NeuN-positive cells in the peri-infarct striatum. These beneficial effects were accompanied by elevated protein levels of BDNF and phosphorylated-TrkB. In conclusion, high-frequency rTMS improves functional recovery possibly by enhancing neurogenesis and activating BDNF/TrkB signaling pathway and conventional 20 Hz rTMS is better than iTBS at enhancing neurogenesis in ischemic rats. PMID:28230741

  11. Not all sources of familiarity are created equal: the case of word frequency and repetition in episodic recognition.

    Science.gov (United States)

    Coane, Jennifer H; Balota, David A; Dolan, Patrick O; Jacoby, Larry L

    2011-07-01

    Low-frequency (LF) words produce higher hit rates and lower false alarm rates than high-frequency (HF) words. This word frequency mirror pattern has been interpreted within dual-process models of recognition, which assume the contributions of a slower recollective process and a relatively fast-acting familiarity process. In the present experiments, recollection and familiarity were placed in opposition using Jacoby, L. L., Journal of Memory and Language, 30, 513-541 (1991), two-list exclusion paradigm with HF and LF words. Exclusion errors to LF words exceeded those to HF words at fast deadlines, whereas the reverse occurred at slow deadlines. In Experiments 2 and 3, false alarms to HF nonpresented lures were higher than to LF nonpresented lures, indicating the use of baseline familiarity for totally new items. Combined, these results indicate that in addition to baseline familiarity and recollection, a third process involving the assessment of a relative change in familiarity is involved in recognition performance. Both relative changes in familiarity and recollection processes have distinct time courses and are engaged when there is diagnostic list information available, whereas baseline familiarity is used when there is no diagnostic information available (e.g., for nonpresented lure items).

  12. Complex-Difference Constrained Compressed Sensing Reconstruction for Accelerated PRF Thermometry with Application to MRI Induced RF Heating

    Science.gov (United States)

    Cao, Zhipeng; Oh, Sukhoon; Otazo, Ricardo; Sica, Christopher T.; Griswold, Mark A.; Collins, Christopher M.

    2014-01-01

    Purpose Introduce a novel compressed sensing reconstruction method to accelerate proton resonance frequency (PRF) shift temperature imaging for MRI induced radiofrequency (RF) heating evaluation. Methods A compressed sensing approach that exploits sparsity of the complex difference between post-heating and baseline images is proposed to accelerate PRF temperature mapping. The method exploits the intra- and inter-image correlations to promote sparsity and remove shared aliasing artifacts. Validations were performed on simulations and retrospectively undersampled data acquired in ex-vivo and in-vivo studies by comparing performance with previously proposed techniques. Results The proposed complex difference constrained compressed sensing reconstruction method improved the reconstruction of smooth and local PRF temperature change images compared to various available reconstruction methods in a simulation study, a retrospective study with heating of a human forearm in vivo, and a retrospective study with heating of a sample of beef ex vivo . Conclusion Complex difference based compressed sensing with utilization of a fully-sampled baseline image improves the reconstruction accuracy for accelerated PRF thermometry. It can be used to improve the volumetric coverage and temporal resolution in evaluation of RF heating due to MRI, and may help facilitate and validate temperature-based methods for safety assurance. PMID:24753099

  13. Fast PRF-based MR thermometry using double-echo EPI: in vivo comparison in a clinical hyperthermia setting.

    Science.gov (United States)

    Dadakova, Tetiana; Gellermann, Johanna; Voigt, Otilia; Korvink, Jan Gerrit; Pavlina, John Matthew; Hennig, Jürgen; Bock, Michael

    2015-08-01

    To develop and test in a clinical setting a double-echo segmented echo planar imaging (DEPI) pulse sequence for proton resonance frequency (PRF)-based temperature monitoring that is faster than conventional PRF thermometry pulse sequences and not affected by thermal changes in tissue conductivity. Four tumor patients underwent between one and nine magnetic resonance (MR)-guided regional hyperthermia treatments. During treatment, the DEPI sequence and a FLASH PRF sequence were run in an interleaved manner to compare the results from both sequences in the same patients and same settings. Temperature maps were calculated based on the phase data of both sequences. Temperature measurements of both techniques were compared using Passing and Bablok regression and the Bland-Altman method. The temperature results from the DEPI and FLASH sequences, on average, do not differ by more than ΔT = 1 °C. DEPI images showed typically more artifacts and approximately a twofold lower signal-to-noise ratio (SNR), but a sufficient temperature precision of 0.5°, which would theoretically allow for a fivefold higher frame rate. The results indicate that DEPI can replace slower temperature measurement techniques for PRF-based temperature monitoring during thermal treatments. The higher acquisition speed can be exploited for hot spot localization during regional hyperthermia as well as for temperature monitoring during fast thermal therapies.

  14. Comparison of the effects of high- and low-frequency repetitive transcranial magnetic stimulation on upper limb hemiparesis in the early phase of stroke.

    Science.gov (United States)

    Sasaki, Nobuyuki; Mizutani, Saneyuki; Kakuda, Wataru; Abo, Masahiro

    2013-05-01

    Recently, high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and low-frequency rTMS (LF-rTMS) are reported to improve motor function significantly in chronic hemiparetic stroke patients. However, few studies have investigated the safety and efficacy of these rTMS modalities introduced during the early phase of stroke. The purpose of this study was to clarify the rTMS modality that is more beneficial for upper limb hemiparesis in the early phase of stroke using a randomized controlled trial. Twenty-nine patients with a hemispheric stroke lesion in the early phase of stroke were examined. Patients were randomly assigned into 3 groups: the HF-rTMS group (10 Hz rTMS to the lesional hemisphere [n = 9]), the LF-rTMS group (1 Hz rTMS to the nonlesional hemisphere [n = 11]), and the sham stimulation group [n = 9]). Patients received sessions for 5 consecutive days. Grip strength and tapping frequency were assessed before and after the intervention. Motor improvement of the affected upper limb after intervention was compared among the 3 groups. All patients completed the 5-day protocol. Both the HF-rTMS and LF-rTMS groups had significant increases in both grip strength and tapping frequency. Comparison of the extent of improvement showed a more significant increase in grip strength and tapping frequency in the HF-rTMS group compared to the sham stimulation group (each P stimulation group. HF-rTMS applied to the lesional hemisphere in the early phase of stroke was more beneficial for motor improvement of the affected upper limb than LF-rTMS. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  15. Effect of the stimulus frequency and pulse number of repetitive transcranial magnetic stimulation on the inter-reversal time of perceptual reversal on the right superior parietal lobule

    Science.gov (United States)

    Nojima, Kazuhisa; Ge, Sheng; Katayama, Yoshinori; Ueno, Shoogo; Iramina, Keiji

    2010-05-01

    The aim of this study is to investigate the effect of the stimulus frequency and pulses number of repetitive transcranial magnetic stimulation (rTMS) on the inter-reversal time (IRT) of perceptual reversal on the right superior parietal lobule (SPL). The spinning wheel illusion was used as the ambiguous figures stimulation in this study. To investigate the rTMS effect over the right SPL during perceptual reversal, 0.25 Hz 60 pulse, 1 Hz 60 pulse, 0.5 Hz 120 pulse, 1 Hz 120 pulse, and 1 Hz 240 pulse biphasic rTMS at 90% of resting motor threshold was applied over the right SPL and the right posterior temporal lobe (PTL), respectively. As a control, a no TMS was also conducted. It was found that rTMS on 0.25 Hz 60 pulse and 1 Hz 60 pulse applied over the right SPL caused shorter IRT. In contrast, it was found that rTMS on 1 Hz 240-pulse applied over the right SPL caused longer IRT. On the other hand, there is no significant difference between IRTs when the rTMS on 0.5 Hz 120 pulse and 1 Hz 120 pulse were applied over the right SPL. Therefore, the applying of rTMS over the right SPL suggests that the IRT of perceptual reversal is effected by the rTMS conditions such as the stimulus frequency and the number of pulses.

  16. Large-scale mass spectrometry-based analysis of Euplotes octocarinatus supports the high frequency of +1 programmed ribosomal frameshift

    Science.gov (United States)

    Wang, Ruanlin; Zhang, Zhiyun; Du, Jun; Fu, Yuejun; Liang, Aihua

    2016-01-01

    Programmed ribosomal frameshifting (PRF) is commonly used to express many viral and some cellular genes. We conducted a genome-wide investigation of +1 PRF in ciliate Euplotes octocarinatus through genome and transcriptome sequencing and our results demonstrated that approximately 11.4% of genes require +1 PRF to produce complete gene products. While nucleic acid-based evidence for candidate genes with +1 PRF is strong, only very limited information is available at protein levels to date. In this study, E. octocarinatus was subjected to large-scale mass spectrometry-based analysis to verify the high frequency of +1 PRF and 226 +1 PRF gene products were identified. Based on the amino acid sequences of the peptides spanning the frameshift sites, typical frameshift motif AAA-UAR for +1 PRF in Euplotes was identified. Our data in this study provide very useful insight into the understanding of the molecular mechanism of +1 PRF. PMID:27597422

  17. Species-Specific Differences in the Activity of PrfA, the Key Regulator of Listerial Virulence Genes▿

    OpenAIRE

    Mauder, Norman; Ecke, Regina; Mertins, Sonja; Loeffler, Daniela I. M.; Seidel, Gerald; Sprehe, Mareen; Hillen, Wolfgang; Goebel, Werner; Müller-Altrock, Stefanie

    2006-01-01

    PrfA, the master regulator of LIPI-1, is indispensable for the pathogenesis of the human pathogen Listeria monocytogenes and the animal pathogen Listeria ivanovii. PrfA is also present in the apathogenic species Listeria seeligeri, and in this study, we elucidate the differences between PrfA proteins from the pathogenic and apathogenic species of the genus Listeria. PrfA proteins of L. monocytogenes (PrfALm and PrfA*Lm), L. ivanovii (PrfALi), and L. seeligeri (PrfALs) were purified, and their...

  18. Different frequency repetitive transcranial magnetic stimulation (rTMS) for posttraumatic stress disorder (PTSD): A systematic review and meta-analysis.

    Science.gov (United States)

    Yan, Tingting; Xie, Qinglian; Zheng, Zhong; Zou, Ke; Wang, Lijuan

    2017-06-01

    Posttraumatic stress disorder (PTSD) is a psychiatric disorder. Repetitive transcranial magnetic stimulation (rTMS) has been found to be effective for treating PTSD, but whether different frequencies have different effects remains controversial. We conducted this systematic review and meta-analysis to address this question. We searched the literature for studies written in English or Chinese in 9 electronic databases from the databases' inception to August 1, 2016. Additional articles were identified from the reference lists of identified studies and from personal reference collections. Eighteen articles were included, and 11 were suitable for the meta-analysis (Combined sample size was 377 (217 in active rTMS groups, 160 in sham-controlled groups)). Low-frequency (LF) rTMS resulted in a significant reduction in the PTSD total score and the depression score (1. PTSD total score: pooled SMD, 0.92; CI, 0.11-1.72; 2. Depression: pooled SMD, 0.54; CI, 0.08-1.00). High-frequency (HF) rTMS showed the following results: 1. PTSD total score: pooled SMD, 3.24; CI, 2.24-4.25; 2. re-experiencing: pooled SMD, -1.77; CI, -2.49-(-1.04); 3. Avoidance: pooled SMD, -1.57; CI, -2.50-(-0.84); 4. hyperarousal: pooled SMD, -1.32; CI, -2.17-(-0.47); 5. depression: pooled SMD, 1.92; CI, 0.80-3.03; and 6. Anxiety: pooled SMD, 2.67; CI, 1.82-3.52. Therefore, both HF and LF rTMS can alleviate PTSD symptoms. Although the evidence is extremely limited, LF rTMS can reduce overall PTSD and depression symptoms. HF rTMS can improve the main and related symptoms of PTSD. However, additional research is needed to substantiate these findings.

  19. The effects of low- and high-frequency repetitive TMS on the input/output properties of the human corticospinal pathway.

    Science.gov (United States)

    Houdayer, E; Degardin, A; Cassim, F; Bocquillon, P; Derambure, P; Devanne, H

    2008-05-01

    The objective of this study was to characterize the effects of various parameters (notably the frequency and intensity) of repetitive transcranial magnetic stimulation (rTMS) applied over the primary motor (M1) and premotor (PMC) cortices on the excitability of the first dorsalis interosseus (FDI) corticospinal pathway. To this end, we applied a comprehensive input-output analysis after fitting the experimental results to a sigmoidal function. Twenty-six healthy subjects participated in the experiments. Repetitive TMS was applied either over M1 or PMC at 1 Hz (LF) for 30 min (1,800 pulses) or at 20 Hz (HF) for 20 min (1,600 pulses). In the HF condition, the TMS intensity was set to 90% (HF(90)) of the FDI's resting motor threshold (RMT). In the LF condition, the TMS intensity was set to either 90% (LF(90)) or 115% (LF(115)) of the RMT. The FDI input/output (I/O) curve was measured on both sides of the body before rTMS (the Pre session) and then during two Post sessions. For each subject, the I/O curves (i.e., the integral of the FDI motor-evoked potential (MEP) vs. stimulus intensity) were fitted using a Boltzmann sigmoidal function. The graph's maximum slope, S (50) and plateau value were then compared between Pre and Post sessions. LF(115) over M1 increased the slope of the FDI I/O curve but did not change the S (50) and plateau value. This also suggested an increase in the RMT. HF(90) led to a more complex effect, with an increase in the slope and a decrease in the S (50) and plateau value. We did not see a cross effect on the homologous FDI corticospinal pathway, and only PMC LF(90) had an effect on ipsilateral corticospinal excitability. Our results suggest that rTMS may exert a more complex influence on cortical network excitability than is usually reported (i.e. simple inhibitory or facilitatory effects). Analysis of the fitted stimulus response curve indicates a dichotomous influence of both low- and high-frequency rTMS on M1 cortical excitability; this may

  20. The use of platelet-rich fibrin (PRF) and PRF-mixed particulated autogenous bone graft in the treatment of bone defects: An experimental and histomorphometrical study.

    Science.gov (United States)

    Kökdere, Nesligül Niyaz; Baykul, Timuçin; Findik, Yavuz

    2015-01-01

    Various materials and techniques have been developed to facilitate bone healing process and reduce its healing period. In recent studies, it is pointed out that, platelet-rich fibrin (PRF) which is derived autogenously from the own blood of the individuals, increase regeneration and accelerate the healing of the wound, due to the consisting various growing factors. The aim of the experimental study is to evaluate the efficiency of PRF and PRF/autogenous graft combination on bone healing in different time intervals. A total of 24 skeletally mature New Zealand rabbits were used. Animals were divided randomly into two groups. Two bone defects with a diameter 3, 3 mm were created on the right and left tibia in all group animals. Only particulate autogeneous bone graft, only PRF, combination of PRF and autogeneous bone graft and empty bone cavity, were performed to all animals. The animals in the first experimental group were sacrificed after 30 days. The animals in the second experimental group were sacrificed after 60 days from the operation. Histomorphometrical and statistical analysis was performed. The data were analyzed using Tukey test (P PRF used alone or used in conjuction with autogenous bone graft, PRF accelerated the healing of the bone defects. There were statistically significant differences in osteoblast, osteoblast and new bone area values in PRF alone and autogenous graft with PRF than the other groups. Our preliminary result demonstrated that PRF increase new bone formation and has a positive effect on early bone healing.

  1. Functional impact of mutational activation on the Listeria monocytogenes central virulence regulator PrfA

    OpenAIRE

    Miner, Maurine D.; Port, Gary C.; Freitag, Nancy E.

    2008-01-01

    The transcriptional activator PrfA is required for the expression of virulence factors necessary for Listeria monocytogenes pathogenesis. PrfA is believed to become activated following L. monocytogenes entry into the cytosol of infected host cells resulting in the induction of target genes whose products are required for bacterial intracellular growth and cell-to-cell spread. Several mutations have been identified that appear to lock PrfA into its highly activated cytosolic form (known as prf...

  2. A proposed protocol for the standardized preparation of PRF membranes for clinical use.

    Science.gov (United States)

    Kobayashi, Mito; Kawase, Tomoyuki; Horimizu, Makoto; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

    2012-09-01

    Upon clinical application, thick platelet-rich fibrin (PRF) is usually compressed to fit the implantation site. However, it is speculated that the preservation of platelets and plasma content depends on the compression methods used. To accurately evaluate the clinical outcome of PRF, the preparation protocol should be standardized. Freshly prepared PRF clots were compressed into a thin membrane by our novel PRF compression device. The localization of platelets was examined by SEM and immunostaining. Growth factor levels were evaluated by bioassays and cytokine-antibody array techniques. The angiogenic activity was examined by the chick chorioallantoic membrane assay and the scratch assay using HUVEC cultures. Platelets were concentrated on the surface of the region adjacent to the red thrombus and this region was subjected to the experiments. Compared to the PRF membrane compressed by dry gauze (G-PRF), the preservation of the plasma content, 3D-fibrin meshwork, and platelets was more intact in the compressor-prepared PRF membrane (C-PRF). Among the growth factors tested, C-PRF contained PDGF isoforms at higher levels, and significantly stimulated cell proliferation and neovascularization. C-PRF may be useful for grafting while minimizing the loss of bioactive factors. This C-PRF preparation protocol is proposed as a standardized protocol for PRF membrane preparation. Copyright © 2012 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  3. The efficacy of cerebellar vermal deep high frequency (theta range) repetitive transcranial magnetic stimulation (rTMS) in schizophrenia: A randomized rater blind-sham controlled study.

    Science.gov (United States)

    Garg, Shobit; Sinha, Vinod Kumar; Tikka, Sai Krishna; Mishra, Preeti; Goyal, Nishant

    2016-09-30

    Repetitive transcranial magnetic stimulation (rTMS) is a promising therapeutic for schizophrenia. Treatment effects of rTMS have been variable across different symptom clusters, with negative symptoms showing better response, followed by auditory hallucinations. Cerebellum, especially vermis and its abnormalities (both structural and functional) have been implicated in cognitive, affective and positive symptoms of schizophrenia. rTMS to this alternate site has been suggested as a novel target for treating patients with this disorder. Hypothesizing cerebellar vermal magnetic stimulation as an adjunct to treat schizophrenia psychopathology, we conducted a double blind randomized sham controlled rTMS study. In this study, forty patients were randomly allocated (using block randomization method) to active high frequency (theta patterned) rTMS (n=20) and sham (n=20) groups. They received 10 sessions over 2 weeks. The Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) scores were assessed at baseline, after last session and at 4 weeks (2 weeks post-rTMS). We found a significantly greater improvement in the group receiving active rTMS sessions, compared to the sham group on negative symptoms, and depressive symptoms. We conclude that cerebellar stimulation can be used as an effective adjunct to treat negative and affective symptoms.

  4. High-rate low-temperature dc pulsed magnetron sputtering of photocatalytic TiO2films: the effect of repetition frequency

    Directory of Open Access Journals (Sweden)

    Strýhal Z

    2007-01-01

    Full Text Available AbstractThe article reports on low-temperature high-rate sputtering of hydrophilic transparent TiO2thin films using dc dual magnetron (DM sputtering in Ar + O2mixture on unheated glass substrates. The DM was operated in a bipolar asymmetric mode and was equipped with Ti(99.5 targets of 50 mm in diameter. The substrate surface temperature Tsurfmeasured by a thermostrip was less than 180 °C for all experiments. The effect of the repetition frequency frwas investigated in detail. It was found that the increase of frfrom 100 to 350 kHz leads to (a an improvement of the efficiency of the deposition process that results in a significant increase of the deposition rate aDof sputtered TiO2films and (b a decrease of peak pulse voltage and sustaining of the magnetron discharge at higher target power densities. It was demonstrated that several hundreds nm thick hydrophilic TiO2films can be sputtered on unheated glass substrates at aD = 80 nm/min, Tsurf < 180 °C when high value of fr = 350 kHz was used. Properties of a thin hydrophilic TiO2film deposited on a polycarbonate substrate are given.

  5. Increase in Short-Interval Intracortical Facilitation of the Motor Cortex after Low-Frequency Repetitive Magnetic Stimulation of the Unaffected Hemisphere in the Subacute Phase after Stroke

    Directory of Open Access Journals (Sweden)

    Eduardo Arruda Mello

    2015-01-01

    Full Text Available Low-frequency repetitive transcranial magnetic stimulation of the unaffected hemisphere (UH-LF-rTMS in patients with stroke can decrease interhemispheric inhibition from the unaffected to the affected hemisphere and improve hand dexterity and strength of the paretic hand. The objective of this proof-of-principle study was to explore, for the first time, effects of UH-LF-rTMS as add-on therapy to motor rehabilitation on short-term intracortical inhibition (SICI and intracortical facilitation (ICF of the motor cortex of the unaffected hemisphere (M1UH in patients with ischemic stroke. Eighteen patients were randomized to receive, immediately before rehabilitation treatment, either active or sham UH-LF-rTMS, during two weeks. Resting motor threshold (rMT, SICI, and ICF were measured in M1UH before the first session and after the last session of treatment. There was a significant increase in ICF in the active group compared to the sham group after treatment, and there was no significant differences in changes in rMT or SICI. ICF is a measure of intracortical synaptic excitability, with a relative contribution of spinal mechanisms. ICF is typically upregulated by glutamatergic agonists and downregulated by gabaergic antagonists. The observed increase in ICF in the active group, in this hypothesis-generating study, may be related to M1UH reorganization induced by UH-LF-rTMS.

  6. Combination Treatment of Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Ataxic Hemiparesis due to Thalamic Hemorrhage

    Directory of Open Access Journals (Sweden)

    Naoki Urushidani

    2017-07-01

    Full Text Available Background: Both low-frequency repetitive transcranial magnetic stimulation (LF-rTMS and intensive occupational therapy (OT are clinically beneficial for post-stroke patients with upper-limb hemiparesis. However, the usefulness of LF-rTMS and intensive OT for ataxic hemiparesis (AH is unknown. Methods: The study subjects included 7 patients with AH. All patients had ataxia and mild hemiparesis without a sensory disturbance that was due to thalamic hemorrhage. Each patient was scheduled to receive 20-min rTMS at 1 Hz at the contralesional cerebral hemisphere followed by 120-min intensive OT, daily for 21 sessions. The primary outcome was the motor function of the affected upper limb that was evaluated by using the Fugl-Meyer Assessment (FMA. In addition, the International Cooperative Ataxia Rating Scale (ICARS score was determined to assess the severity of ataxia. Results: All patients completed the protocol without any adverse effects. The FMA score significantly increased after treatment. Notably, the ICARS score also significantly decreased. Conclusions: Our proposed combination treatment is a safe and feasible neurorehabilitative intervention for patients with AH due to thalamic hemorrhage. Our results demonstrate the possibility that rTMS in combination with intensive OT could improve motor function and alleviated ataxia in patients with AH.

  7. Plant Programmed Cell Death Caused by an Autoactive Form of Prf Is Suppressed by Co-Expression of the Prf LRR Domain

    Institute of Scientific and Technical Information of China (English)

    Xinran Du; Min Miao; Xinrong Ma; Yongsheng Liu; Joseph C.Kuhl; Gregory B.Martin; Fangming Xiao

    2012-01-01

    In tomato,the NBARC-LRR resistance (R) protein Prf acts in concert with the Pto or Fen kinase to determine immunity against Pseudomonas syringae pv.tomato (Pst).Prf-mediated defense signaling is initiated by the recognition of two sequence-unrelated Pst-secreted effector proteins,AvrPto and AvrPtoB,by tomato Pto or Fen.Prf detects these interactions and activates signaling leading to host defense responses including localized programmed cell death (PCD) that is associated with the arrest of Pst growth.We found that Prf variants with single amino acid substitutions at D1416 in the IHD motif (isoleucine-histidine-aspartic acid) in the NBARC domain cause effector-independent PCD when transiently expressed in leaves of Nicotiana benthamiana,suggesting D1416 plays an important role in activation of Prf.The N-terminal region of Prf (NPrf) and the LRR domain are required for this autoactive Prf cell death signaling but dispensable for accumulation of the PrfD1416V protein.Significantly,co-expression of the Prf LRR but not NPrf,with PrfD1416V,AvrPto/Pto,AvrPtoB/Pto,an autoactive form of Pto (PtoY207D),or Fen completely suppresses PCD.However,the Prf LRR does not interfere with PCD caused by Rpi-blb1D475V,a distinct R protein-mediated PCD signaling event,or that caused by overexpression of MAPKKKα,a protein acting downstream of Prf.Furthermore,we found the PrfD1416V protein is unable to accumulate in plant cells when co-expressed with the Prf LRR domain,likely explaining the cell death suppression.The mechanism for the LRR-induced degradation of PrfD1416V is unknown but may involve interference in the intramolecular interactions of Prf or to binding of the unattached LRR to other host proteins that are needed for Prf stability.

  8. Primed low-frequency repetitive transcranial magnetic stimulation and constraint-induced movement therapy in pediatric hemiparesis: a randomized controlled trial.

    Science.gov (United States)

    Gillick, Bernadette T; Krach, Linda E; Feyma, Tim; Rich, Tonya L; Moberg, Kelli; Thomas, William; Cassidy, Jessica M; Menk, Jeremiah; Carey, James R

    2014-01-01

    The aim of this study was to determine the feasibility and efficacy of five treatments of 6 Hz primed, low-frequency, repetitive transcranial magnetic stimulation (rTMS) combined with constraint-induced movement therapy (CIMT) to promote recovery of the paretic hand in children with congenital hemiparesis. Nineteen children with congenital hemiparesis aged between 8 and 17 years (10 males, nine females; mean age 10 years 10 months, SD 2 years 10 months; Manual Ability Classification Scale levels I-III) underwent five sessions of either real rTMS (n=10) or sham rTMS (n=9) alternated daily with CIMT. CIMT consisted of 13 days of continuous long-arm casting with five skin-check sessions. Each child received a total of 10 hours of one-to-one therapy. The primary outcome measure was the Assisting Hand Assessment (AHA) and the secondary outcome variables were the Canadian Occupational Performance Measure (COPM) and stereognosis. A Wilcoxon signed-rank sum test was used to analyze differences between pre- and post-test scores within the groups. Analysis of covariance was used to compute mean differences between groups adjusting for baseline. Fisher's exact test was used to compare individual change in AHA raw scores with the smallest detectable difference (SDD) of 4 points. All participants receiving treatment finished the study. Improvement in AHA differed significantly between groups (p=0.007). No significant differences in the secondary outcome measures were found. Eight out of 10 participants in the rTMS/CIMT group showed improvement greater than the SDD, but only two out of nine in the sham rTMS/CIMT group showed such improvement (p=0.023). No serious adverse events occurred. Primed, low-frequency rTMS combined with CIMT appears to be safe, feasible, and efficacious in pediatric hemiparesis. Larger clinical trials are now indicated. © 2013 Mac Keith Press.

  9. Sigma B Contributes to PrfA-Mediated Virulence in Listeria monocytogenes

    OpenAIRE

    Nadon, Celine A.; Bowen, Barbara M.; Wiedmann, Martin; Boor, Kathryn J.

    2002-01-01

    Transcription of the Listeria monocytogenes positive regulatory factor A protein (PrfA) is initiated from either of two promoters immediately upstream of prfA (prfAp1 and prfAp2) or from the upstream plcA promoter. We demonstrate that prfAp2 is a functional σB-dependent promoter and that a sigB deletion mutation affects the virulence phenotype of L. monocytogenes. Thus, the alternative sigma factor σB contributes to virulence in L. monocytogenes.

  10. Talking about the MIL-PRF-39016F Specification%学习MIL-PRF-39016F的一点肤浅体会

    Institute of Scientific and Technical Information of China (English)

    郑天丕; 方珍

    2005-01-01

    MIL-PRF-39016F对MIL-PRF-39016E作了一些修改,如引出端电镀工艺、洁净处理和微粒检查、PIND、接触电阻及先断后合等.笔者对MIL-PRF-39016F作了一点肤浅的分析,认为它对贯彻现行的GJB 65B(idt MIL-PRF-39016E)有着很大的意义.

  11. Functional Similarities between the Listeria monocytogenes Virulence Regulator PrfA and Cyclic AMP Receptor Protein: the PrfA* (Gly145Ser) Mutation Increases Binding Affinity for Target DNA

    OpenAIRE

    Vega, Yolanda; Dickneite, Carmen; Ripio, Maria Teresa; Böckmann, Regine; González Zörn, Bruno; Novella, Susanna; Dominguez-Bernal, Gustavo; Goebel, Werner; Vazquez-Boland, Jose A

    1998-01-01

    Most Listeria monocytogenes virulence genes are positively regulated by the PrfA protein, a transcription factor sharing sequence similarities with cyclic AMP (cAMP) receptor protein (CRP). Its coding gene, prfA, is regulated by PrfA itself via an autoregulatory loop mediated by the upstream PrfA-dependent plcA promoter. We have recently characterized prfA* mutants from L. monocytogenes which, as a result of a single amino acid substitution in PrfA, Gly145Ser, constitutively overexpress prfA ...

  12. Effect of low-frequency repetitive transcranial magnetic stimulation combining task-oriented training on upper limb motor function recovery after stroke

    Directory of Open Access Journals (Sweden)

    Hong-bin WANG

    2017-07-01

    Full Text Available Objective To investigate the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS combined with task-oriented training on the recovery of upper limb motor function of stroke patients. Methods A total of 42 patients with hemiplegia after stroke were randomly divided into control group (N = 20 and treatment group (N = 22. Control group received routine rehabilitation training and task-oriented training, and treatment group received low-frequency (1 Hz rTMS over the contralesional cortex addition to routine rehabilitation and task-oriented training. Fugl-Meyer Assessment Scale for Upper Extremity (FMA-UE and Wolf Motor Function Test (WMFT were used to evaluate upper limb motor function of all patients before treatment, after 4-week treatment and 3 months after treatment. The latency and central motor conduction time (CMCT of motor-evoked potential (MEP in the contralesional cortex were recorded and analyzed. Results Compared with control group, FMA-UE score (P = 0.006 and WMFT score (P = 0.024 were significantly increased in treatment group. There was significant difference in FMA-AUE score (P = 0.000 and WMFT score (P = 0.000 at different time points. Compared with before treatment, FMA-UE score (P = 0.000, for all and WMFT score (P = 0.000, for all of patients in both groups were all significantly increased after 4-week treatment and 3 months after treatment. Besides, FMA-UE score (P = 0.000, for all and WMFT score (P = 0.000, for all 3 months after treatment were higher than those after 4-week treatment. There was no statistically significant difference between 2 groups on the latency (P = 0.979 and CMCT (P = 0.807 of MEP before and after treatment, and so was the difference on the latency (P = 0.085 and CMCT (P = 0.507 of MEP in the contralesional cortex at different time points (before treatment, after 4-week treatment and 3 months after treatment. Conclusions Low-frequency rTMS over the contralesional cortex combined

  13. Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation on Naming Abilities in Early-Stroke Aphasic Patients: A Prospective, Randomized, Double-Blind Sham-Controlled Study

    Directory of Open Access Journals (Sweden)

    Konrad Waldowski

    2012-01-01

    Full Text Available Background and Purpose. Functional brain imaging studies with aphasia patients have shown increased cortical activation in the right hemisphere language homologues, which hypothetically may represent a maladaptive strategy that interferes with aphasia recovery. The aim of this study was to investigate whether low-frequency repetitive transcranial magnetic stimulation (rTMS over the Broca’s homologues in combination with speech/language therapy improves naming in early-stroke aphasia patients. Methods. 26 right-handed aphasic patients in the early stage (up to 12 weeks of a first-ever left hemisphere ischemic stroke were randomized to receive speech and language therapy combined with real or sham rTMS. Prior to each 45-minute therapeutic session (15 sessions, 5 days a week, 30 minutes of 1-Hz rTMS was applied. Outcome measures were obtained at baseline, immediately after 3 weeks of experimental treatment and 15 weeks; posttreatment using the Computerized Picture Naming Test. Results. Although both groups significantly improved their naming abilities after treatment, no significant differences were noted between the rTMS and sham stimulation groups. The additional analyses have revealed that the rTMS subgroup with a lesion including the anterior part of language area showed greater improvement primarily in naming reaction time 15 weeks after completion of the therapeutic treatment. Improvement was also demonstrated in functional communication abilities. Conclusions. Inhibitory rTMS of the unaffected right inferior frontal gyrus area in combination with speech and language therapy cannot be assumed as an effective method for all poststroke aphasia patients. The treatment seems to be beneficial for patients with frontal language area damage, mostly in the distant time after finishing rTMS procedure.

  14. Effects of low-frequency repetitive transcranial magnetic stimulation and neuromuscular electrical stimulation on upper extremity motor recovery in the early period after stroke: a preliminary study.

    Science.gov (United States)

    Tosun, Aliye; Türe, Sabiha; Askin, Ayhan; Yardimci, Engin Ugur; Demirdal, Secil Umit; Kurt Incesu, Tülay; Tosun, Ozgur; Kocyigit, Hikmet; Akhan, Galip; Gelal, Fazıl Mustafa

    2017-07-01

    To assess the efficacy of inhibitory repetitive transcranial magnetic stimulation (rTMS) and neuromuscular electrical stimulation (NMES) on upper extremity motor function in patients with acute/subacute ischemic stroke. Twenty-five ischemic acute/subacute stroke subjects were enrolled in this randomized controlled trial. Experimental group 1 received low frequency (LF) rTMS to the primary motor cortex of the unaffected side + physical therapy (PT) including activities to improve strength, flexibility, transfers, posture, balance, coordination, and activities of daily living, mainly focusing on upper limb movements; experimental group 2 received the same protocol combined with NMES to hand extensor muscles; and the control group received only PT. Functional magnetic resonance imaging (fMRI) scan was used to evaluate the activation or inhibition of the affected and unaffected primary motor cortex. No adverse effect was reported. Most of the clinical outcome scores improved significantly in all groups, however no statistically significant difference was found between groups due to the small sample sizes. The highest percent improvement scores were observed in TMS + NMES group (varying between 48 and 99.3%) and the lowest scores in control group (varying between 13.1 and 28.1%). Hand motor recovery was significant in both experimental groups while it did not change in control group. Some motor cortex excitability changes were also observed in fMRI. LF-rTMS with or without NMES seems to facilitate the motor recovery in the paretic hand of patients with acute/subacute ischemic stroke. TMS or the combination of TMS + NMES may be a promising additional therapy in upper limb motor training. Further studies with larger numbers of patients are needed to establish their effectiveness in upper limb motor rehabilitation of stroke.

  15. Effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) on spontaneously hypertensive rats, an animal model of attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Kim, Jungyun; Park, Heamen; Yu, Seong-Lan; Jee, Sungju; Cheon, Keun-Ah; Song, Dong Ho; Kim, Seung Jun; Im, Woo-Young; Kang, Jaeku

    2016-10-01

    The current treatment of choice for attention deficit hyperactivity disorder (ADHD) is pharmacotherapy. A search for new treatment options is underway, however, as the wide application of drugs to the general population of patients with ADHD is limited by side effects and the variance of pharmacokinetic effects of the drugs in each patient. In the present study, we applied repetitive transcranial magnetic stimulation (rTMS), a non-invasive treatment used in a number of other psychiatric disorders, to spontaneously hypertensive rats (SHRs), an animal model of ADHD, in order to assess the efficacy of the treatment in modifying behavioural symptoms as well as levels of dopamine, noradrenaline, serotonin, and brain-derived neurotrophic factor (BDNF). A total of fifteen sessions of high-frequency rTMS treatment were administered. Behavioural symptoms were observed using open field, Y-maze, and elevated plus-maze tests. Upon completion of the experiments, rats were sacrificed, and the neurochemical changes in brain tissue were analysed using high performance liquid chromatography and Western blotting. The SHRs treated with rTMS tended to exhibit less locomotor activity in the open field test over the course of treatment, but there was no improvement in inattention as measured by the Y-maze test. Furthermore, BDNF concentration increased and noradrenaline concentration decreased in the prefrontal cortex of SHRs treated with rTMS. The results of the present preclinical study indicate that rTMS may constitute a new modality of treatment for patients with ADHD, through further evaluation of specific treatment parameters as well as safety and efficacy in humans are required.

  16. Effect of high-frequency repetitive transcranial magnetic stimulation on motor cortical excitability and sensory nerve conduction velocity in subacute-stage incomplete spinal cord injury patients.

    Science.gov (United States)

    Cha, Hyun Gyu; Ji, Sang-Goo; Kim, Myoung-Kwon

    2016-07-01

    [Purpose] The aim of the present study was to determine whether repetitive transcranial magnetic stimulation can improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. [Subjects and Methods] This study was conducted on 20 subjects with diagnosed paraplegia due to spinal cord injury. These 20 subjects were allocated to an experimental group of 10 subjects that underwent active repetitive transcranial magnetic stimulation or to a control group of 10 subjects that underwent sham repetitive transcranial magnetic stimulation. The SCI patients in the experimental group underwent active repetitive transcranial magnetic stimulation and conventional rehabilitation therapy, whereas the spinal cord injury patients in the control group underwent sham repetitive transcranial magnetic stimulation and conventional rehabilitation therapy. Participants in both groups received therapy five days per week for six-weeks. Latency, amplitude, and sensory nerve conduction velocity were assessed before and after the six week therapy period. [Results] A significant intergroup difference was observed for posttreatment velocity gains, but no significant intergroup difference was observed for amplitude or latency. [Conclusion] repetitive transcranial magnetic stimulation may be improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients.

  17. Quasi-flat-top frequency-doubled Nd:glass laser for pumping of high-power Ti:sapphire amplifiers at a 0.1 Hz repetition rate.

    Science.gov (United States)

    Yanovsky, Victor; Kalinchenko, Galina; Rousseau, Pascal; Chvykov, Vladimir; Mourou, Gerard; Krushelnick, Karl

    2008-04-20

    A Nd:glass laser based on a novel design delivers up to 120 J energy pulses with a quasi-flat-top spatial profile at a 0.1 Hz repetition rate. The laser output is frequency-doubled with 50% efficiency and used to pump Ti:sapphire amplifiers. The developed design is perspective for use in the currently contemplated next step in ultra-high-intensity laser development.

  18. Application of PRF in surgical management of periapical lesions.

    Science.gov (United States)

    Singh, Smita; Singh, Arunendra; Singh, Sourav; Singh, Rashmi

    2013-01-01

    Platelet rich fibrin is widely used in stimulation and acceleration of soft tissue and bone healing because of local and continuous delivery of growth factors and proteins, mimicking the needs of the physiological wound healing and reparative tissue processes. This article will serve to introduce a second generation platelet concentrate, platelet-rich fibrin (PRF). Fifteen cases are presented in which conventional endodontic therapy failed to resolve the problem and periapical root-end surgery was required. At the end of six months, all patients showed complete bone regeneration. Production of a dense, cross-linked, physically robust PRF made of intact platelets and fibrin by high-speed centrifugation in the absence of exogenous thrombin, yields an ideal scaffold for use in tissue repair.

  19. Range ambiguity resolution for high PRF pulse-Doppler radar

    Science.gov (United States)

    Postema, G. B.

    The range ambiguity resolution for high 'PRF pulse-Doppler radars can be resolved using a simple algorithm based on residue arithmetic. The unambiguous range is found from R = T + R(a), where T is the output of a look-up table and R(a) is one of the measured ambiguous ranges. This formula is easily extended to multiple PRF ranging systems, where three or more measurements are required for the ambiguity resolution. Target obscuration in clutter reduces the visibility and leads, especially in dense target environments, to ghost ranges. It is shown that long range coverage requires a small resolved pulse length and PRFs as low as practical in the intended clutter and target environment. Special attention is given to the generation of sparsely populated look-up tables that reduce the ghosting problem. A practical example for an S-band surveillance radar is presented.

  20. Effects of repetition within trials and frequency of trial sessions on quantitative parameters of vertical force peak in horses with naturally occurring lameness.

    Science.gov (United States)

    Kaido, Mari; Kilborne, Allison H; Sizemore, Joy L; Reisbig, Nathalie A; Aarnes, Turi K; Bertone, Alicia L

    2016-07-01

    OBJECTIVE To analyze the effects of vertical force peak (VFP) of repition within trials and between trial sessions in horses with naturally occurring appendicular lameness. ANIMALS 20 lame horses acclimated to trotting over a force plate. PROCEDURES Kinetic gait data were collected by use of a force plate regarding affected and contralateral limbs of lame horses that completed 5 valid repetitions in each of 5 sessions performed at 0, 3, 6, 12, and 24 hours, constituting 1 trial/horse. Data were compared within and among repetitions and sessions, and factors influencing VFP values were identified. RESULTS VFP values differed for lame limbs after 3 valid repetitions were performed within a session and when the interval between sessions was 3 hours. Direction of change reflected less lameness (greater VFP). Lamer horses (≥ grade 4/5) had this finding to a greater degree than did less lame horses. Results were similar for contralateral limbs regarding valid repetitions within a session; however, VFP decreased when the interval between sessions exceeded 6 hours. The coefficient of variation for VFP was ≤ 8% within sessions and ≤ 6% between sessions. The asymmetry index for VFP did not change throughout the study. CONCLUSIONS AND CLINICAL RELEVANCE Lameness profiles obtained through kinetic gait analysis of horses with naturally occurring lameness were most accurate when valid repetitions were limited to 3 and the interval between sessions within a trial was > 3 hours. Findings suggested that natural lameness may be as suitable as experimentally induced lameness for lameness research involving horses.

  1. Effects of low-frequency repetitive transcranial magnetic stimulation combined with intensive speech therapy on cerebral blood flow in post-stroke aphasia.

    Science.gov (United States)

    Hara, Takatoshi; Abo, Masahiro; Kobayashi, Kentaro; Watanabe, Motoi; Kakuda, Wataru; Senoo, Atushi

    2015-10-01

    We provided an intervention to chronic post-stroke aphasic patients using low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) guided by a functional magnetic resonance imaging (fMRI) evaluation of language laterality, combined with intensive speech therapy (ST). We performed a single photon emission-computed tomography (SPECT) scan pre- and post-intervention and investigated the relationship between cerebral blood flow (CBF) and language function. Fifty right-handed chronic post-stroke aphasic patients were enrolled in the study. During their 11-day hospital admission, the patients received a 40-min session of 1-Hz LF-rTMS on the left or right hemisphere, according to language localization identified by the fMRI evaluation, and intensive ST daily for 10 days, except for Sunday. A SPECT scan and language evaluation by the Standard Language Test of Aphasia (SLTA) were performed at the time of admission and at 3 months following discharge. We calculated laterality indices (LIs) of regional CBF (rCBF) in 13 language-related Brodmann area (BA) regions of interest. In patients who received LF-rTMS to the intact right hemisphere (RH-LF-rTMS), the improvement in the total SLTA score was significantly correlated with the pre- and post-intervention change of LI (ΔLI) in BA44. In patients who received LF-rTMS to the lesional left hemisphere (LH-LF-rTMS), this association was not observed. Analyses of the SLTA subscales and rCBF ΔLI demonstrated that in the RH-LF-rTMS group, the SLTA Speaking subscale scores were significantly correlated with ΔLIs in BA11, 20, and 21, and the SLTA Writing subscale scores were significantly correlated with ΔLIs in BA6 and 39. Conversely, in the LH-LF-rTMS group, the SLTA Speaking subscale scores were correlated with ΔLI in BA10, and the SLTA Reading subscale scores were significantly correlated with ΔLIs in BA13, 20, 22, and 44. Our results suggest the possibility that fMRI-guided LF-rTMS combined with intensive ST may

  2. Clinical and immunohistochemical performance of lyophilized platelet-rich fibrin (Ly-PRF) on tissue regeneration.

    Science.gov (United States)

    Zhang, Jianming; Qi, Xingying; Luo, Xiaoding; Li, Dan; Wang, Haorong; Li, Ting

    2017-06-01

    Platelet-rich fibrin (PRF) has been widely used in oral implantology and other fields, but benefits of the fresh PRF (FPRF (fresh platelet-rich fibrin)) were consequently limited because of its short-term application. Thus, a protocol for the combination of PRF and lyophilization comes up in the present study to address the issue of PRF storage and delayed clinical application, which has little been reported in this field at home and abroad by now. The aim of the present study was to evaluate the applicability of lyophilized platelet-rich fibrin (Ly-PRF) used as the scaffold material for craniofacial tissue regeneration and to compare its biochemical properties with commonly used fresh PRF. Two volunteers with both genders were selected as the source of PRF and Ly-PRF samples. Macro- and micro-scopic appearance evaluation as well as immunohistochemical comparison were performed on PRF samples before and after freeze-drying at -196°C. The second experimental phase was to observe clinical performance when fresh and lyophilized PRF were applied in guided bone regeneration (GBR) operations in 39 patients losing teeth in the anterior maxillary region who required an oral implantation followed by labial bone grafting. The conventional histological and transmission electron microscopy images showed the microstructure of Ly-PRF, which resembled a mesh containing apparently irregularly shaped platelets with less alpha-granule than fresh PRF in micro and a translucent membrane with less elasticity than fresh PRF in macro. Simultaneous immunohistological staining results showed positive expression of PDGF-BB, IL-1, IL-4, TNF, TGF-β1 in both fresh and lyophilized PRF, while the expression of PDGF-BB, IL-1, TNF, TGF-β1 has no statistical difference between them (P > .05) but that of IL-4 in Ly-PRF is statistically higher than in fresh PRF (P  .05). This study strongly supports that lyophilization at -196°C does not largely influence the expression of bioactive

  3. A class of high-pass digital MTI filters with nonuniform PRF

    NARCIS (Netherlands)

    Prinsen, P.J.A.

    1973-01-01

    A class of digital feed-forward filters is developed, satisfying the requirement of a maximally flat stopband characteristic at zero frequency if the pulse-repetition frequency is modulated. A simple algorithm is given to obtain the filter coefficients. Some properties are summarized

  4. Highly-efficient 1-GHz-repetition-frequency femtosecond Yb3+:KY(WO42 laser for super-continuum generation

    Directory of Open Access Journals (Sweden)

    Leburn C.G.

    2013-03-01

    Full Text Available We present a 1.024-GHz-repetition-rate femtosecond Yb3+:KY(WO42 laser with 61% optical-to-optical efficiency and 69% slope efficiency, generating a supercontinuum of bandwidth 400 nm in silica photonic-crystal fibre. RIN measurements of the laser yielded values <0.1%.

  5. Analysis of the Peak Resistance Frequency Method.

    Science.gov (United States)

    Wang, Boshuo; Weiland, James D

    2016-10-01

    This study analyzes the peak resistance frequency (PRF) method described by Mercanzini et al., a method that can easily extract the tissue resistance from impedance spectroscopy for many neural engineering applications but has no analytical description thus far. Mathematical analyses and computer simulations were used to explore underlying principles, accuracy, and limitations of the PRF method. The mathematical analyses demonstrated that the PRF method has an inherent but correctable deviation dependent on the idealness of the electrode-tissue interface, which is validated by simulations. Further simulations show that both frequency sampling and noise affect the accuracy of the PRF method, and in general, it performs less accurately than least squares methods. However, the PRF method achieves simplicity and reduced measurement and computation time at the expense of accuracy. From the qualitative results, the PRF method can work with reasonable precision and simplicity, although its limitation and the idealness of the electrode-tissue interface involved should be taken into consideration. This paper provides a mathematical foundation for the PRF method and its practical implementation.

  6. Referenceless PRF thermometry with multi-echo processing to monitor prostate ablation

    Science.gov (United States)

    Rieke, Viola; Kinsey, Adam M.; Nau, William H.; Diederich, Chris J.; Sommer, Graham; Pauly, Kim Butts

    2007-05-01

    Referenceless proton resonance frequency (PRF) shift thermometry provides a means to measure temperature changes during minimally invasive thermotherapy that is inherently robust to motion and tissue displacement. An extension to the referenceless method allows temperature estimation in the presence of phase discontinuities that occur at water/fat interfaces between prostate and periprostatic fat. Three images at different echo times are acquired and binary water and fat maps are generated from a Dixon reconstruction. For the background phase estimation, water and fat regions are treated separately and the phase offset between the two tissue types is determined. Here we present a new pulse sequence to acquire the necessary three images, which allows for temperature monitoring of the prostate with increased temporal resolution, optimal temperature resolution with respect to heating pattern of transurethral US applicators, and provides high resolution anatomical images. The method is demonstrated during in vivo thermal ablation of canine prostate.

  7. Optimally enhanced heating for focused ultrasound surgery with split foci, dual-frequency, or multi foci

    Science.gov (United States)

    Lu, Mingzhu; Guan, Yubo; Dong, Tengju; Liu, Fenfen; Wan, Mingxi

    2017-03-01

    To substantially enhance heating in HIFU treatment, several methods such as split foci, multi foci, and dual-frequency modes are used. The enhanced-cavitation heating protocols are implemented experimentally in BSA gel-phantom using four-element split-focus array. Using dual frequency of 1.2 and 2.4 MHz, the superimposing of two frequency pressures at confocal region can enhance nucleation cavitation and inertial cavitation activity. When using 135° phase shift combined with dual frequency of 1.2 and 2.4 MHz, the peak negative pressure reach maximum due to peak-negative pressures of two frequencies occur at same time, resulting strong cavitation activities. When using dual frequency of 1.2 and 2.4 MHz, 25-Hz pulse-repetition frequency (PRF), both 135° and 180° phase shift protocols, the experiment results show the largest lesion size of 10.5 × 10.5 × 11 mm3, quickest lesion inception time of less than 0.2 s, therefore, both 135° and 180° phase shift protocols are most efficient in enhanced-cavitation heating. The filtered-PCD mean square waveforms reveal that the strong inertial-cavitation activities involve in those two treatments. The lesion size of four foci of 180° phase shift, single frequency, 25 Hz PRF, is 2 times that of 0° phase shift, single frequency even if the peak intensity of 180° case is half less than that of 0° phase shift case. When arrange multi foci using phased array in a style of a wavelength distance between neighbor foci in focal plane, the result is the same as that using split foci of 180° phase shift and single frequency.

  8. In vivo evaluation of multi-echo hybrid PRF/T1 approach for temperature monitoring during breast MR-guided focused ultrasound surgery treatments.

    Science.gov (United States)

    Todd, Nick; Diakite, Mahamadou; Payne, Allison; Parker, Dennis L

    2014-09-01

    To evaluate the precision of in vivo temperature measurements in adipose and glandular breast tissue using a multi-echo hybrid PRF/T1 pulse sequence. A high-bandwidth, multi-echo hybrid PRF/T1 sequence was developed for monitoring temperature changes simultaneously in fat- and water-based tissues. The multiple echoes were combined with the optimal weightings for magnitude and phase images, allowing for precise measurement of both T1 and the proton resonance frequency (PRF) shift. The sequence was tested during in vivo imaging of 10 healthy volunteers in a breast-specific MR-guided focused ultrasound system and also during focused ultrasound heating of excised breast adipose tissue. The in vivo results indicated that the sequence can measure PRF temperatures with 1.25 × 1.25 × 3.5 mm resolution, 1.9 s temporal resolution, and 1.0°C temperature precision, and can measure T1 values with 3.75 × 3.75 × 3.5 mm resolution, 3.8 s temporal resolution, and 2.5%-4.8% precision. The excised tissue heating experiments demonstrate the sequence's ability to monitor temperature changes simultaneously in water- and fat-based tissues. The addition of a high-bandwidth, multi-echo readout to the hybrid PRF/T1 sequence improves the precision of each measurement, providing a sequence that will be beneficial to several MR-guided thermal therapies. Copyright © 2013 Wiley Periodicals, Inc.

  9. The use of platelet-rich fibrin (PRF) and PRF-mixed particulated autogenous bone graft in the treatment of bone defects: An experimental and histomorphometrical study

    National Research Council Canada - National Science Library

    Kökdere, Nesligül Niyaz; Baykul, Timuçin; Findik, Yavuz

    2015-01-01

    .... In recent studies, it is pointed out that, platelet-rich fibrin (PRF) which is derived autogenously from the own blood of the individuals, increase regeneration and accelerate the healing of the wound, due to the consisting various growing factors...

  10. Task Repetition and Second Language Speech Processing

    Science.gov (United States)

    Lambert, Craig; Kormos, Judit; Minn, Danny

    2017-01-01

    This study examines the relationship between the repetition of oral monologue tasks and immediate gains in L2 fluency. It considers the effect of aural-oral task repetition on speech rate, frequency of clause-final and midclause filled pauses, and overt self-repairs across different task types and proficiency levels and relates these findings to…

  11. Challenges in comparing the acute cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) vs. electroconvulsive therapy (ECT) in major depression: A systematic review.

    Science.gov (United States)

    Kedzior, Karina Karolina; Schuchinsky, Maria; Gerkensmeier, Imke; Loo, Colleen

    2017-03-02

    The present study aimed to systematically compare the cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and electroconvulsive therapy (ECT) in head-to-head studies with major depression (MDD) patients. A systematic literature search identified six studies with 219 MDD patients that were too heterogeneous to reliably detect meaningful differences in acute cognitive outcomes after ECT vs. HF-rTMS. Cognitive effects of brain stimulation vary depending on the timeframe and methods of assessment, stimulation parameters, and maintenance treatment. Thus, acute and longer-term differences in cognitive outcomes both need to be investigated at precisely defined timeframes and with similar instruments assessing comparable functions.

  12. Platelet Rich Fibrin (PRF) in Regeneration of Intrabony Defects- A Randomized Controlled Trial.

    Science.gov (United States)

    Kumar Patel, Gauresh; Kumar Gujjari, Sheela; Kumar S C, Veerendra

    2017-08-18

    Platelet-rich fibrin (PRF) is a autologous non transfusional hemo-component with a high concentration of platelets. It incorporates leukocytes, platelets and growth factors within the dense fibrin matrix and can be used as healing biomaterial. This study assessed the adjunctive use of PRF in regenerative management of intrabony defects in comparison with open flap debridement. 26 bilateral defects (13 per group) in 13 patients were randomized as either PRF (Test group) or Open flap debridement alone (control group) sites. Probing depth (PD), clinical attachment level (CAL) and bone probing depth were recorded. Reduction in defect depth and percentage of bone fill was assessed radiographically. Primary outcomes assessed were the changes in pocket depth, attachment level and percentage of bone fill assessed at 6months, 9 months and 12 months. Secondary outcome was assessment of wound healing using a wound healing index. The PRF group showed significant improvement in clinical parameters over control group at 6, 9, and 12 months. PRF group showed a bone fill of 45.18±7.57 percent which was statistically significant compared to 21.6±9.3 percent seen in control group at end of study period. Wound healing index (WHI) also showed significant advantages for the PRF group. PRF also showed significant soft tissue healing and reduction in probing depth. The adjunctive use of PRF to conventional open flap debridement may be potentially used in the treatment of intrabony defects.

  13. Evidence that PrfA, the pleiotropic activator of virulence genes in Listeria monocytogenes, can be present but inactive.

    OpenAIRE

    Renzoni, A; Klarsfeld, A; Dramsi, S.; Cossart, P

    1997-01-01

    All virulence genes of Listeria monocytogenes identified to date are positively regulated by PrfA, a transcriptional activator belonging to the Crp-Fnr family. Low temperature and cellobiose are two environmental signals known to repress expression of virulence genes in L. monocytogenes. In the present work, we analyzed the effect of temperature and cellobiose on the expression of the PrfA protein. At low temperature, PrfA was undetected, although prfA monocistronic transcripts are present. I...

  14. The Influence of the Frequency of Functional Markers on Repetitive Imitation of Syntactic Constructions in Children with Specific Language Impairment, from Their Own Language Productions

    Science.gov (United States)

    Leroy, Sandrine; Parisse, Christophe; Maillart, Christelle

    2013-01-01

    Several studies provide considerable insight into the role that frequency plays in language development. However, no study has investigated the direct relationship between frequency and grammatical acquisition in children with specific language impairment (SLI). In this study, we focus specifically on the influence of the frequency of functional…

  15. High Prf Metal Vapor Laser Active Media For Visual And Optical Monitoring

    Science.gov (United States)

    Torgaev, S. N.; Trigub, M. V.; Evtushenko, G. S.; Evtushenko, T. G.

    2016-01-01

    In this paper the feasibility of using metal vapor lasers for visual and optical monitoring of fast processes is discussed. The theoretical calculations consistent with the experimental study have been performed. The possibility of visualizing objects with pulse repetition frequency of the brightness amplifier up to 60 kHz has been demonstrated. The visualization results of the corona discharge are also given.

  16. Lyophilized platelet-rich fibrin (PRF) promotes craniofacial bone regeneration through Runx2.

    Science.gov (United States)

    Li, Qi; Reed, David A; Min, Liu; Gopinathan, Gokul; Li, Steve; Dangaria, Smit J; Li, Leo; Geng, Yajun; Galang, Maria-Therese; Gajendrareddy, Praveen; Zhou, Yanmin; Luan, Xianghong; Diekwisch, Thomas G H

    2014-05-14

    Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF) as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF). LPRF caused a 4.8-fold±0.4-fold elevation in Runt-related transcription factor 2 (Runx2) expression in alveolar bone cells, compared to a 3.6-fold±0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (pPRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering.

  17. Lyophilized Platelet-Rich Fibrin (PRF Promotes Craniofacial Bone Regeneration through Runx2

    Directory of Open Access Journals (Sweden)

    Qi Li

    2014-05-01

    Full Text Available Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF. LPRF caused a 4.8-fold ± 0.4-fold elevation in Runt-related transcription factor 2 (Runx2 expression in alveolar bone cells, compared to a 3.6-fold ± 0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (p < 0.001 when compared to fresh PRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering.

  18. Based on the UC3825 chip repetition frequency laser power supply design and research%基于UC3825芯片重频激光电源设计与研究

    Institute of Scientific and Technical Information of China (English)

    陈景忠

    2012-01-01

    随着微电子技术和电子电力技术的不断发展,高频开关稳压电源正以体积小、效率高等优点而广泛应用于各种军用、民用仪器仪表、控制设备产品中。激光电源作为一种特殊开关电源,和普通开关电源的区别是负载伏安特性完全不同,本文主要介绍了一种基于UC3825芯片的重复频率激光电源的工作原理,它采用半桥式变换电路,利用UC3825进行电流型调制,用IR2110双通道驱动芯片驱动场效应管,采用单片机AT89C51组成的控制电路对脉冲激光氙灯进行重复频率充放电控制,最终成功实现了一种基于UC3825芯片的重复频率激光电源的研制。%With microelectronic technology and power electronic technology development, high frequency switching power supply with small volume, high efficiency, etc. are widely used in various military, civilian insmunents, control equipment products. Laser power as a kind of special switching power supply, switching power supply and the common difference is load volt - ampere characteristics are quite different, this paper mainly introduces one kind based on the UC3825 chip repetition frequency laser power supply works, which utilizes half- bridge converter circuit, using UC3825 electric cun'ent modulation, using IR2110 dual channel driving chip driving FET, the single chip microcomputer AT89C.51 control circuit composed of a pulse laser repetitive frequency of xenon lamp charging and discharging control, ultimately the suecesafitl implementation of the one kind based on the UC3825 chip repetition frequency laser power supply.

  19. In vivo evaluation of titanium-prepared platelet-rich fibrin (T-PRF): a new platelet concentrate.

    Science.gov (United States)

    Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Fıratlı, Erhan

    2013-07-01

    We have developed a new, titanium-prepared, platelet-rich fibrin (T-PRF) together with the protocol for forming it, which is based on the hypothesis that titanium tubes may be more effective at activating platelets than the glass tubes used by Chouckroun in his platelet-rich fibrin (PRF) method. The aim of this study was to find a suitable animal model in which to evaluate the method and to investigate the efficacy of T-PRF for wound healing. Blood samples from 6 rabbits were used to confirm the protocol for formation of T-PRF. We evaluated T-PRF or T-PRF-like clots morphologically using scanning electron microscopy (EM). Blood samples from 5 rabbits were used to develop an experiment in which to evaluate the effects of T-PRF on wound healing. The mucoperiosteal flaps were filled with autologous T-PRF membranes from the vestibule in the anterior mandibular regions. Samples collected from the surgical sites were stained with haematoxylin and eosin. We found a mature fibrin network in T-PRF clots that had been centrifuged for 15 min at 3500 rpm and, 15 days after placement of the membrane, we found newly-forming connective tissue and islets of bony tissue in the T-PRF membrane. These results show that T-PRF could induce the formation of new bone with new connective tissue in a rabbit model of wound healing within 30 days of treatment. Published by Elsevier Ltd.

  20. TNFα secretion of monocytes exposed to pulsed radiofrequency treatment: a possible working mechanism of PRF chronic pain management.

    Science.gov (United States)

    Maretto, Fabio; Vennik, Marco; Albers, Kim I; van Duijn, Bert

    2014-06-01

    Pulsed radiofrequency treatment (PRF) is a promising new technique increasingly used in treatment of chronic pain. The molecular working mechanism of PRF is not exactly known and is currently being investigated. This study investigates a possible role of PRF-induced modulation of TNFα secretion by differentiated monocytes in chronic pain management. The results show no significant PRF-induced change in TNFα secretion of lipopolysaccharides (LPS)-stimulated monocytes. However, PRF does significantly increase TNFα secretion of differentiated monocytes that have not been stimulated with LPS. This may indicate a possible role of PRF treatment in increasing TNFα production of nonstimulated monocytes. More research is needed to determine whether this is truly a part of the working mechanism of PRF in chronic pain management and which other factors are involved. © 2013 World Institute of Pain.

  1. Toxicity of laser irradiated photoactive fluoride PrF3 nanoparticles toward bacteria

    Science.gov (United States)

    Pudovkin, M. S.; Korableva, S. L.; Krasheninnicova, A. O.; Nizamutdinov, A. S.; Semashko, V. V.; Zelenihin, P. V.; Alakshin, E. M.; Nevzorova, T. A.

    2014-11-01

    The article is devoted to exploration of biological effects of crystalline PrF3 nanoparticles toward Salmonella typhimurium TA 98 bacteria under the laser irradiation. Obtained results show bactericidal activity of PrF3 nanoparticles and optimal parameters of laser irradiation (power of laser irradiation, wavelength, diameter of the laser spoil, and exposure time) have been found under which the effects of bactericidal activity become the most significant. Survival of bacterial cells under laser irradiation with wavelength 532 nm in colloidal solution of PrF3 nanoparticles was 39%, 34%, 20% for exposure times 5 minutes, 15 minutes and 30 minutes, correspondingly.

  2. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part V: histologic evaluations of PRF effects on bone allograft maturation in sinus lift.

    Science.gov (United States)

    Choukroun, Joseph; Diss, Antoine; Simonpieri, Alain; Girard, Marie-Odile; Schoeffler, Christian; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Dohan, David M

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. The use of platelet gel to improve bone regeneration is a recent technique in implantology. However, the biologic properties and real effects of such products remain controversial. In this article, we therefore attempt to evaluate the potential of PRF in combination with freeze-dried bone allograft (FDBA) (Phoenix; TBF, France) to enhance bone regeneration in sinus floor elevation. Nine sinus floor augmentations were performed. In 6 sites, PRF was added to FDBA particles (test group), and in 3 sites FDBA without PRF was used (control group). Four months later for the test group and 8 months later for the control group, bone specimens were harvested from the augmented region during the implant insertion procedure. These specimens were treated for histologic analysis. Histologic evaluations reveal the presence of residual bone surrounded by newly formed bone and connective tissue. After 4 months of healing time, histologic maturation of the test group appears to be identical to that of the control group after a period of 8 months. Moreover, the quantities of newly formed bone were equivalent between the 2 protocols. Sinus floor augmentation with FDBA and PRF leads to a reduction of healing time prior to implant placement. From a histologic point of view, this healing time could be reduced to 4 months, but large-scale studies are still necessary to validate these first results.

  3. Effect of low frequency repetitive transcranial magnetic stimulation on kindling-induced changes in electrophysiological properties of rat CA1 pyramidal neurons.

    Science.gov (United States)

    Moradi Chameh, Homeira; Janahmadi, Mahyar; Semnanian, Saeed; Shojaei, Amir; Mirnajafi-Zadeh, Javad

    2015-05-01

    In this study, the effect of repetitive transcranial magnetic stimulation (rTMS) on the kindling induced changes in electrophysiological firing properties of hippocampal CA1 pyramidal neurons was investigated. Male Wistar rats were kindled by daily electrical stimulation of the basolateral amygdala in a semi-rapid manner (12 stimulations/day) until they achieved stage-5 seizure. One group (kindled+rTMS (KrTMS)) of animals received rTMS (240 pulses at 1 Hz) at 5 min after termination of daily kindling stimulations. Twenty-four hours following the last kindling stimulation electrophysiological properties of hippocampal CA1 pyramidal neurons were investigated using a whole-cell patch clamp technique, under current clamp condition. Amygdala kindling significantly decreased the adaptation index, post-afterhyperpolarization, rheobase current, utilization time, and delay to the first rebound spike. It also caused an increase in the voltage sag, number of rebound spikes and number of evoked action potential. Results of the present study revealed that application of rTMS following kindling stimulations had antiepileptogenic effects. In addition, application of rTMS prevented hyperexcitability of CA1 pyramidal neurons induced by kindling and conserved the normal neuronal firing.

  4. Tunable repetition rate VECSEL for resonant acoustic-excitation of nanostructures

    Science.gov (United States)

    Chen Sverre, T.; Head, C. R.; Turnbull, A. P.; Shaw, E. A.; Tropper, A. C.; Muskens, O. L.

    2016-03-01

    We report a passively mode-locked InGaAs-quantum well VECSEL, emitting a constant pulse train at an average output power of 18 mW and emission wavelength of 1035 nm, with a continuously tunable pulse repetitionfrequency (PRF) between 0.88 - 1.88 GHz. Pulse duration was 230 fs over 80% of that range. Here we propose a technique making use of the demonstrated VECSEL PRF tunability for a resonant frequency-domain pumpprobe spectroscopic technique for acoustic interrogation of nanostructures. Simulation of suitable GHz acoustic resonators to demonstrate this technique is described.

  5. Drift correction for accurate PRF-shift MR thermometry during mild hyperthermia treatments with MR-HIFU.

    Science.gov (United States)

    Bing, Chenchen; Staruch, Robert M; Tillander, Matti; Köhler, Max O; Mougenot, Charles; Ylihautala, Mika; Laetsch, Theodore W; Chopra, Rajiv

    2016-09-01

    There is growing interest in performing hyperthermia treatments with clinical magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) therapy systems designed for tissue ablation. During hyperthermia treatment, however, due to the narrow therapeutic window (41-45 °C), careful evaluation of the accuracy of proton resonant frequency (PRF) shift MR thermometry for these types of exposures is required. The purpose of this study was to evaluate the accuracy of MR thermometry using a clinical MR-HIFU system equipped with a hyperthermia treatment algorithm. Mild heating was performed in a tissue-mimicking phantom with implanted temperature sensors using the clinical MR-HIFU system. The influence of image-acquisition settings and post-acquisition correction algorithms on the accuracy of temperature measurements was investigated. The ability to achieve uniform heating for up to 40 min was evaluated in rabbit experiments. Automatic centre-frequency adjustments prior to image-acquisition corrected the image-shifts in the order of 0.1 mm/min. Zero- and first-order phase variations were observed over time, supporting the use of a combined drift correction algorithm. The temperature accuracy achieved using both centre-frequency adjustment and the combined drift correction algorithm was 0.57° ± 0.58 °C in the heated region and 0.54° ± 0.42 °C in the unheated region. Accurate temperature monitoring of hyperthermia exposures using PRF shift MR thermometry is possible through careful implementation of image-acquisition settings and drift correction algorithms. For the evaluated clinical MR-HIFU system, centre-frequency adjustment eliminated image shifts, and a combined drift correction algorithm achieved temperature measurements with an acceptable accuracy for monitoring and controlling hyperthermia exposures.

  6. 电磁导波激励脉冲群最佳重复频率确定%Determination on repetition frequency of electromagnetic guided wave excited by impulse cluster

    Institute of Scientific and Technical Information of China (English)

    孙钦蕾; 刘美全; 周海林

    2012-01-01

    电磁导波检测技术因其非接触耦合的特性已被广泛应用于各种金属管道无损检测领域中。但导波的激励脉冲群重复频率的确定长久以来却没有一个有效的解决方法。为此,本文提出了以有、无缺陷的重复脉冲群检测信号的相关性作为判别标准,选取电磁导波激励脉冲群最佳重复频率,并从检测信号特征提取和识别的角度验证了本文选取的激励脉冲群最佳重复频率可有效提高导波检测信号之间的区分度,减小检测信号间的干扰,提高缺陷识别的准确性。%As a result of contactless coupling, electromagnetic guided wave detection technology is used extensively to detect various metallic pipelines, however, it hasn't achieved an effective solution about reception frequency of guided wave exciting impulse cluster. So, in this paper, the correlation between flaw detection signal from repetition impulse cluster and no defect is proposed as criterion to choose optimal repetition frequency of exciting impulse cluster, through feature extraction and identification of testing signal, which is prove that it can improve efficiently discrimination degree of guided wave signals, decrease noise jamming, and advance precision of defect identification.

  7. [The relevance of Choukroun's Platelet-Rich Fibrin (PRF) during middle ear surgery: preliminary results].

    Science.gov (United States)

    Braccini, F; Tardivet, L; Dohan Ehrenfest, D M

    2009-01-01

    To evaluate the relevance of Leucocyte- and Platelet-Rich Fibrin (L-PRF, Choukroun's technique) Concentrates during tympanoplasty. 152 myringoplasties (including 2 cases with bilateral tympanic perforations) were treated by the senior surgeon in 150 patients, 63 women and 87 males aged between 25 and 55-years-old, between december 2004 and june 2008. These patients showed non marginal tympanic perforations, sized from punctiform to subtotal. For the smallest perforations, a PRF cylinder was used alone to fill the perforation without preparing a tympanomeatus flap (Champagne plug technique). For perforations largest than the third of the tympanic surface, temporal aponeurosis graft in underlay was preferred, and optimized by the lateral application of a PRF membrane (hamburger technique). 6 failures were recorded in this case series, with tympans showing residual microperforations, after a minimum follow-up of 6 months. The success rate was thus close to 96%. The mean success rate without PRF is normally 85%. All failures were recorded on large non marginal lesions. PRF will never save an inadequate surgical procedure, but it offers both mechanical and inflammatory protection to the tympanic graft and accelerates cell proliferation and matrix remodelling. Moreover, this autologous biomaterial induces no undesirable tissue reaction, is easy, quick and cheap to produce and is easily manipulated during the surgical procedure. It seems a precious help for the otologist, in order to improve tympanic healing. PRF potential applications in the middle-ear surgery seem numerous.

  8. Repetitive maladaptive behavior: beyond repetition compulsion.

    Science.gov (United States)

    Bowins, Brad

    2010-09-01

    Maladaptive behavior that repeats, typically known as repetition compulsion, is one of the primary reasons that people seek psychotherapy. However, even with psychotherapeutic advances it continues to be extremely difficult to treat. Despite wishes and efforts to the contrary repetition compulsion does not actually achieve mastery, as evidenced by the problem rarely resolving without therapeutic intervention, and the difficulty involved in producing treatment gains. A new framework is proposed, whereby such behavior is divided into behavior of non-traumatic origin and traumatic origin with some overlap occurring. Repetitive maladaptive behavior of non-traumatic origin arises from an evolutionary-based process whereby patterns of behavior frequently displayed by caregivers and compatible with a child's temperament are acquired and repeated. It has a familiarity and ego-syntonic aspect that strongly motivates the person to retain the behavior. Repetitive maladaptive behavior of traumatic origin is characterized by defensive dissociation of the cognitive and emotional components of trauma, making it very difficult for the person to integrate the experience. The strong resistance of repetitive maladaptive behavior to change is based on the influence of both types on personality, and also factors specific to each. Psychotherapy, although very challenging at the best of times, can achieve the mastery wished and strived for, with the aid of several suggestions provided.

  9. Generation of Shear Alfvén Waves by Repetitive High Power Microwave Pulses Near the Electron Plasma Frequency - A laboratory study of a ``Virtual Antenna''

    Science.gov (United States)

    Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

    2015-11-01

    ELF / ULF waves are important in terrestrial radio communications but difficult to launch using ground-based structures due to their enormous wavelengths. In spite of this generation of such waves by field-aligned ionospheric heating modulation was first demonstrated using the HAARP facility. In the future heaters near the equator will be constructed and laboratory experiments on cross-field wave propagation could be key to the program's success. Here we report a detailed laboratory study conducted on the Large Plasma Device (LaPD) at UCLA. In this experiment, ten rapid pulses of high power microwaves (250 kW X-band) near the plasma frequency were launched transverse to the background field, and were modulated at a variable fraction (0.1-1.0) of fci. Along with bulk electron heating and density modification, the microwave pulses generated a population of fast electrons. The field-aligned current carried by the fast electrons acted as an antenna that radiated shear Alfvén waves. It was demonstrated that a controllable arbitrary frequency (f frequency variation and power dependence of the virtual antenna is also presented. This work is supported by an AFOSR MURI award, and conducted at the Basic Plasma Science Facility at UCLA funded by DoE and NSF.

  10. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part II: platelet-related biologic features.

    Science.gov (United States)

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. In this second article, we investigate the platelet-associated features of this biomaterial. During PRF processing by centrifugation, platelets are activated and their massive degranulation implies a very significant cytokine release. Concentrated platelet-rich plasma platelet cytokines have already been quantified in many technologic configurations. To carry out a comparative study, we therefore undertook to quantify PDGF-BB, TGFbeta-1, and IGF-I within PPP (platelet-poor plasma) supernatant and PRF clot exudate serum. These initial analyses revealed that slow fibrin polymerization during PRF processing leads to the intrinsic incorporation of platelet cytokines and glycanic chains in the fibrin meshes. This result would imply that PRF, unlike the other platelet concentrates, would be able to progressively release cytokines during fibrin matrix remodeling; such a mechanism might explain the clinically observed healing properties of PRF.

  11. In vitro release of growth factors from platelet-rich fibrin (PRF): a proposal to optimize the clinical applications of PRF.

    Science.gov (United States)

    Su, Chen Yao; Kuo, Ya Po; Tseng, Yu Hong; Su, Ching-Hua; Burnouf, Thierry

    2009-07-01

    Determine the release of growth factors (GF) from platelet-rich fibrin (PRF) and supernatant serum to optimize clinical use. Platelet-derived growth factors-AB (PDGF-AB), transforming growth factor-beta1 (TGF-beta1), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and insulin-like growth factor-1 (IGF-1) were quantified in PRF releasate and in the supernatant serum (N = 8) over 300 minutes after clot formation. Protein profiles were determined by SDS-PAGE. Mean quantity of PDGF-AB, TGF-ss1, VEGF, and EGF in PRF releasate increased significantly to about 52, 72, 1, and 3 ng, respectively, whereas mean IGF-1 content remained at 250 ng. GF was also found in serum supernatant. Protein profiles of the releasates and the supernatant serum were similar. The PRF membrane should be used immediately after formation to maximize release of GF to the surgical site. The remaining fluid can be recovered as an additional source of GF for grafting.

  12. Grammatical Change through Repetition.

    Science.gov (United States)

    Arevart, Supot

    1989-01-01

    The effect of repetition on grammatical change in an unrehearsed talk is examined based on a case study of a single learner. It was found that repetition allows for accuracy monitoring in that errors committed in repeated contexts undergo correction. Implications for teaching are discussed. (23 references) (LB)

  13. The Negative Repetition Effect

    Science.gov (United States)

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  14. Roles of repetitive sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bell, G.I.

    1991-12-31

    The DNA of higher eukaryotes contains many repetitive sequences. The study of repetitive sequences is important, not only because many have important biological function, but also because they provide information on genome organization, evolution and dynamics. In this paper, I will first discuss some generic effects that repetitive sequences will have upon genome dynamics and evolution. In particular, it will be shown that repetitive sequences foster recombination among, and turnover of, the elements of a genome. I will then consider some examples of repetitive sequences, notably minisatellite sequences and telomere sequences as examples of tandem repeats, without and with respectively known function, and Alu sequences as an example of interspersed repeats. Some other examples will also be considered in less detail.

  15. Roles of repetitive sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bell, G.I.

    1991-12-31

    The DNA of higher eukaryotes contains many repetitive sequences. The study of repetitive sequences is important, not only because many have important biological function, but also because they provide information on genome organization, evolution and dynamics. In this paper, I will first discuss some generic effects that repetitive sequences will have upon genome dynamics and evolution. In particular, it will be shown that repetitive sequences foster recombination among, and turnover of, the elements of a genome. I will then consider some examples of repetitive sequences, notably minisatellite sequences and telomere sequences as examples of tandem repeats, without and with respectively known function, and Alu sequences as an example of interspersed repeats. Some other examples will also be considered in less detail.

  16. Prf immune complexes of tomato are oligomeric and contain multiple Pto-like kinases that diversify effector recognition.

    Science.gov (United States)

    Gutierrez, Jose R; Balmuth, Alexi L; Ntoukakis, Vardis; Mucyn, Tatiana S; Gimenez-Ibanez, Selena; Jones, Alexandra M E; Rathjen, John P

    2010-02-01

    Cytoplasmic recognition of pathogen virulence effectors by plant NB-LRR proteins leads to strong induction of defence responses termed effector triggered immunity (ETI). In tomato, a protein complex containing the NB-LRR protein Prf and the protein kinase Pto confers recognition of the Pseudomonas syringae effectors AvrPto and AvrPtoB. Although structurally unrelated, AvrPto and AvrPtoB interact with similar residues in the Pto catalytic cleft to activate ETI via an unknown mechanism. Here we show that the Prf complex is oligomeric, containing at least two molecules of Prf. Within the complex, Prf can associate with Pto or one of several Pto family members including Fen, Pth2, Pth3, or Pth5. The dimerization surface for Prf is the novel N-terminal domain, which also coordinates an intramolecular interaction with the remainder of the molecule, and binds Pto kinase or a family member. Thus, association of two Prf N-terminal domains brings the associated kinases into close promixity. Tomato lines containing Prf complexed with Pth proteins but not Pto possessed greater immunity against P. syringae than tomatoes lacking Prf. This demonstrates that incorporation of non-Pto kinases into the Prf complex extends the number of effector proteins that can be recognized.

  17. Compilation of PRF Canyon Floor Pan Sample Analysis Results

    Energy Technology Data Exchange (ETDEWEB)

    Pool, Karl N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Minette, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wahl, Jon H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Greenwood, Lawrence R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Coffey, Deborah S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McNamara, Bruce K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bryan, Samuel A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Scheele, Randall D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Delegard, Calvin H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sinkov, Sergey I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Soderquist, Chuck Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brown, Garrett N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clark, Richard A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-30

    On September 28, 2015, debris collected from the PRF (236-Z) canyon floor, Pan J, was observed to exhibit chemical reaction. The material had been transferred from the floor pan to a collection tray inside the canyon the previous Friday. Work in the canyon was stopped to allow Industrial Hygiene to perform monitoring of the material reaction. Canyon floor debris that had been sealed out was sequestered at the facility, a recovery plan was developed, and drum inspections were initiated to verify no additional reactions had occurred. On October 13, in-process drums containing other Pan J material were inspected and showed some indication of chemical reaction, limited to discoloration and degradation of inner plastic bags. All Pan J material was sealed back into the canyon and returned to collection trays. Based on the high airborne levels in the canyon during physical debris removal, ETGS (Encapsulation Technology Glycerin Solution) was used as a fogging/lock-down agent. On October 15, subject matter experts confirmed a reaction had occurred between nitrates (both Plutonium Nitrate and Aluminum Nitrate Nonahydrate (ANN) are present) in the Pan J material and the ETGS fixative used to lower airborne radioactivity levels during debris removal. Management stopped the use of fogging/lock-down agents containing glycerin on bulk materials, declared a Management Concern, and initiated the Potential Inadequacy in the Safety Analysis determination process. Additional drum inspections and laboratory analysis of both reacted and unreacted material are planned. This report compiles the results of many different sample analyses conducted by the Pacific Northwest National Laboratory on samples collected from the Plutonium Reclamation Facility (PRF) floor pans by the CH2MHill’s Plateau Remediation Company (CHPRC). Revision 1 added Appendix G that reports the results of the Gas Generation Rate and methodology. The scope of analyses requested by CHPRC includes the determination of

  18. Injectable platelet rich fibrin (i-PRF): opportunities in regenerative dentistry?

    Science.gov (United States)

    Miron, Richard J; Fujioka-Kobayashi, Masako; Hernandez, Maria; Kandalam, Umadevi; Zhang, Yufeng; Ghanaati, Shahram; Choukroun, Joseph

    2017-02-02

    Platelet rich plasma (PRP) has been utilized in regenerative dentistry as a supra-physiological concentrate of autologous growth factors capable of stimulating tissue regeneration. Despite this, concerns have been expressed regarding the use of anti-coagulants, agents known to inhibit wound healing. In this study, a liquid formulation of platelet rich fibrin (PRF) termed injectable-PRF (i-PRF) without the use of anti-coagulants was investigated. Standard PRP and i-PRF (centrifuged at 700 rpm (60G) for 3 min) were compared for growth factor release up to 10 days (8 donor samples). Furthermore, fibroblast biocompatibility at 24 h (live/dead assay); migration at 24 h; proliferation at 1, 3, and 5 days, and expression of PDGF, TGF-β, and collagen1 at 3 and 7 days were investigated. Growth factor release demonstrated that in general PRP had higher early release of growth factors whereas i-PRF showed significantly higher levels of total long-term release of PDGF-AA, PDGF-AB, EGF, and IGF-1 after 10 days. PRP showed higher levels of TGF-β1 and VEGF at 10 days. While both formulations exhibited high biocompatibility and higher fibroblast migration and proliferation when compared to control tissue-culture plastic, i-PRF induced significantly highest migration whereas PRP demonstrated significantly highest cellular proliferation. Furthermore, i-PRF showed significantly highest mRNA levels of TGF-β at 7 days, PDGF at 3 days, and collagen1 expression at both 3 and 7 days when compared to PRP. i-PRF demonstrated the ability to release higher concentrations of various growth factors and induced higher fibroblast migration and expression of PDGF, TGF-β, and collagen1. Future animal research is now necessary to further validate the use of i-PRF as a bioactive agent capable of stimulating tissue regeneration. The findings from the present study demonstrate that a potent formulation of liquid platelet concentrates could be obtained without use of anti-coagulants.

  19. Platelet-rich fibrin (PRF): an autologous packing material for middle ear microsurgery.

    Science.gov (United States)

    Garin, P; Mullier, F; Gheldof, D; Dogne, Jean-Michel; Putz, L; Van Damme, J P

    2014-01-01

    To assess the use of PRF prepared using an optimised protocol in middle ear surgery as a substitute for conventional packing products of animal origin such as collagen derived from porcine skin. A retrospective study of 108 patients in whom optimised PRF was used exclusively to pack the external auditory canal or middle ear. The effectiveness or harmlessness of the PRF was evaluated by assessing a range of parameters. A morphological comparison was also made of PRF produced using the Choukroun procedure and our procedure. The success rate of the repair of the tympanic membrane one year after the surgery was 45/48 patients. In 5 of 63 patients in whom a retro-auricular approach and wall-up technique were used, granuloma was observed along the incision in the ear canal. Granuloma was not seen in any of the 23 patients undergoing a procedure with an endaural approach. The use of a material prepared from patients themselves and not of animal origin has numerous advantages in terms of biocompatibility and safety, without any adverse effect on the success rate for general middle ear procedures. The protocol is simple and does not prolong the time spent by the patient in the operating theatre. The Choukroun technique should be modified to prevent excessive failure rates in PRF processing.

  20. Significant differences in the frequency of transcriptional units, types and numbers of repetitive elements, GC content, and the number of CpG islands between a 1010-kb G-band genomic segment on chromosome 9q31.3 and a 1200-kb R-band genomic segment on chromosome 3p21.3

    National Research Council Canada - National Science Library

    Daigo, Y; Isomura, M; Nishiwaki, T; Suzuki, K; Maruyama, O; Takeuchi, K; Yamane, Y; Hayashi, R; Minami, M; Hojo, Y; Uchiyama, I; Takagi, T; Nakamura, Y

    1999-01-01

    ... 3p21.3 corresponding to an R-band region. The two segments were significantly different with respect to the frequency of transcriptional units, the types and numbers of repetitive elements present, their GC content, and the number of CpG islands...

  1. Trialogue: Preparation, Repetition and...

    Science.gov (United States)

    Oberg, Antoinette; And Others

    1996-01-01

    This paper interrogates both curriculum theory and the limits and potentials of textual forms. A set of overlapping discourses (a trialogue) focuses on inquiring into the roles of obsession and repetition in creating deeply interpretive locations for understanding. (SM)

  2. A Low Power/Area Digital FIR Filter Design Based on PRF Framework

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel DSP to ASIC (Application Specific Integrated Circuit) architecture desig n methodology is presented in this paper for reducing power/area consumption. Traditional methods always focus on optimizing hardware structure or algorithm sep arately. The authors propose a new method called PRF (ParallelingReducing-Fol-ding) framework to combine hardware optimization with algorithm simplification. In the first step,paralleling, unfolding technology is applied to divide one data path into several channels and expose the redundancy of the algorithm. In the second step, reducing,decoupling theory is used to reduce computational complexity.In the last step, folding, timemultiplexing method is used to merge similar components. As an exoteric methodology framework, many optimization methods can be integrated into the PRF framework.To optimize a 3N taps FIR (Fincte Impact Response)and obtain a content result,PRF methodology framework is applied.

  3. Influence of geometric and material properties on artifacts generated by interventional MRI devices: Relevance to PRF-shift thermometry

    Energy Technology Data Exchange (ETDEWEB)

    Tatebe, Ken, E-mail: Ken.Tatebe@gmail.com [Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390 (United States); Ramsay, Elizabeth; Kazem, Mohammad; Peikari, Hamed [Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5 (Canada); Mougenot, Charles [Philips Healthcare, 281 Hillmount Road, Markham, Ontario L6C 2S3 (Canada); Bronskill, Michael [Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5, Canada and Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario M5G2M9 (Canada); Chopra, Rajiv [Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390 (United States); Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390 (United States); Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5 (Canada); Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario M5G2M9 (Canada)

    2016-01-15

    Purpose: Magnetic resonance imaging (MRI) is capable of providing valuable real-time feedback during medical procedures, partly due to the excellent soft-tissue contrast available. Several technical hurdles still exist to seamless integration of medical devices with MRI due to incompatibility of most conventional devices with this imaging modality. In this study, the effect of local perturbations in the magnetic field caused by the magnetization of medical devices was examined using finite element analysis modeling. As an example, the influence of the geometric and material characteristics of a transurethral high-intensity ultrasound applicator on temperature measurements using proton resonance frequency (PRF)-shift thermometry was investigated. Methods: The effect of local perturbations in the magnetic field, caused by the magnetization of medical device components, was examined using finite element analysis modeling. The thermometry artifact generated by a transurethral ultrasound applicator was simulated, and these results were validated against analytic models and scans of an applicator in a phantom. Several parameters were then varied to identify which most strongly impacted the level of simulated thermometry artifact, which varies as the applicator moves over the course of an ablative high-intensity ultrasound treatment. Results: Key design parameters identified as having a strong influence on the magnitude of thermometry artifact included the susceptibility of materials and their volume. The location of components was also important, particularly when positioned to maximize symmetry of the device. Finally, the location of component edges and the inclination of the device relative to the magnetic field were also found to be important factors. Conclusions: Previous design strategies to minimize thermometry artifact were validated, and novel design strategies were identified that substantially reduce PRF-shift thermometry artifacts for a variety of device

  4. Influence of geometric and material properties on artifacts generated by interventional MRI devices: Relevance to PRF-shift thermometry.

    Science.gov (United States)

    Tatebe, Ken; Ramsay, Elizabeth; Mougenot, Charles; Kazem, Mohammad; Peikari, Hamed; Bronskill, Michael; Chopra, Rajiv

    2016-01-01

    Magnetic resonance imaging (MRI) is capable of providing valuable real-time feedback during medical procedures, partly due to the excellent soft-tissue contrast available. Several technical hurdles still exist to seamless integration of medical devices with MRI due to incompatibility of most conventional devices with this imaging modality. In this study, the effect of local perturbations in the magnetic field caused by the magnetization of medical devices was examined using finite element analysis modeling. As an example, the influence of the geometric and material characteristics of a transurethral high-intensity ultrasound applicator on temperature measurements using proton resonance frequency (PRF)-shift thermometry was investigated. The effect of local perturbations in the magnetic field, caused by the magnetization of medical device components, was examined using finite element analysis modeling. The thermometry artifact generated by a transurethral ultrasound applicator was simulated, and these results were validated against analytic models and scans of an applicator in a phantom. Several parameters were then varied to identify which most strongly impacted the level of simulated thermometry artifact, which varies as the applicator moves over the course of an ablative high-intensity ultrasound treatment. Key design parameters identified as having a strong influence on the magnitude of thermometry artifact included the susceptibility of materials and their volume. The location of components was also important, particularly when positioned to maximize symmetry of the device. Finally, the location of component edges and the inclination of the device relative to the magnetic field were also found to be important factors. Previous design strategies to minimize thermometry artifact were validated, and novel design strategies were identified that substantially reduce PRF-shift thermometry artifacts for a variety of device orientations. These new strategies are being

  5. The tomato NBARC-LRR protein Prf interacts with Pto kinase in vivo to regulate specific plant immunity.

    Science.gov (United States)

    Mucyn, Tatiana S; Clemente, Alfonso; Andriotis, Vasilios M E; Balmuth, Alexi L; Oldroyd, Giles E D; Staskawicz, Brian J; Rathjen, John P

    2006-10-01

    Immunity in tomato (Solanum lycopersicum) to Pseudomonas syringae bacteria expressing the effector proteins AvrPto and AvrPtoB requires both Pto kinase and the NBARC-LRR (for nucleotide binding domain shared by Apaf-1, certain R gene products, and CED-4 fused to C-terminal leucine-rich repeats) protein Prf. Pto plays a direct role in effector recognition within the host cytoplasm, but the role of Prf is unknown. We show that Pto and Prf are coincident in the signal transduction pathway that controls ligand-independent signaling. Pto and Prf associate in a coregulatory interaction that requires Pto kinase activity and N-myristoylation for signaling. Pto interacts with a unique Prf N-terminal domain outside of the NBARC-LRR domain and resides in a high molecular weight recognition complex dependent on the presence of Prf. In this complex, both Pto and Prf contribute to specific recognition of AvrPtoB. The data suggest that the role of Pto is confined to the regulation of Prf and that the bacterial effectors have evolved to target this coregulatory molecular switch.

  6. Growth Factor Variation in Two Types of Autologous Platelet Biomaterials: PRP Versus PRF.

    Science.gov (United States)

    Arora, Satyam; Kotwal, Urvershi; Dogra, Mitu; Doda, Veena

    2017-06-01

    Autologous platelet biomaterials represent a key source of cytokines and growth factors extensively used for clinical and surgical applications involving tissue regeneration; wound healing and tissue repair. In this communication we discuss the growth factors released by activated platelet rich plasma (PRP) and platelet rich fibrin (PRF) releasate. Our study highlights that significantly higher growth factors (TGF-ß1) are released by activated PRP as compared to releasate of PRF. The various growth factors released by both platelet products are significantly higher than the baseline concentration in the whole blood and have different bio-mechanism hence should be individualized as per the clinical indication.

  7. The positive effects of high-frequency right dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation on memory, correlated with increases in brain metabolites detected by proton magnetic resonance spectroscopy in recently detoxified alcohol-dependent patients

    Directory of Open Access Journals (Sweden)

    Qiao J

    2016-09-01

    Full Text Available Jun Qiao,1,2 Guixing Jin,1,2 Licun Lei,3 Lan Wang,1,2 Yaqiang Du,3 Xueyi Wang1,2 1Institute of Mental Health, The First Hospital of Hebei Medical University, 2Brain Ageing and Cognitive Neuroscience Laboratory, Hebei Medical University, 3Department of Radiology, The First Hospital of Hebei Medical University, Hebei, People’s Republic of China Objective: To explore the effect of right dorsolateral prefrontal cortex (DLPFC repetitive transcranial magnetic stimulation (rTMS on memory, and its correlation with levels of hippocampal brain metabolites detected by proton magnetic resonance spectroscopy (1H-MRS in recently detoxified alcohol-dependent patients. Materials and methods: In this randomized, double-blind sham-controlled trial, alcohol-dependent patients were enrolled and randomized into two groups: the experimental group (rTMS, 10 Hz, on right DLPFC, 20 sessions and the control group (sham stimulation. Memory function was assessed using Hopkins Verbal Learning Test-Revised (HVLT-R and Brief Visuospatial Memory Test-Revised (BVMT-R before and after treatment. 1H-MRS was used to detect the levels of N-acetyl aspartic acid (NAA, choline (Cho, and creatine (Cr in bilateral hippocampi before and after treatment. Results: Thirty-eight patients (18 in the experimental group and 20 in the control group were included in the analyses. The experimental group showed significantly greater changes in HVLT-R, BVMT-R, NAA/Cr, and Cho/Cr after rTMS from baseline than the control group. The percentage change in BVMT-R and HVLT-R correlated with the percentage change in NAA/Cr and Cho/Cr in the right brain. Conclusion: High-frequency right DLPFC rTMS was associated with improvement in memory dysfunction, which is correlated with levels of hippocampal brain metabolites detected by 1H-MRS in recently detoxified alcohol-dependent patients. Keywords: alcohol dependence, memory, repetitive transcranial magnetic stimulation, MR spectroscopy

  8. A Novel Mutation within the Central Listeria monocytogenes Regulator PrfA That Results in Constitutive Expression of Virulence Gene Products

    OpenAIRE

    Wong, Kendy K. Y.; Freitag, Nancy E.

    2004-01-01

    The PrfA protein of Listeria monocytogenes functions as a key regulatory factor for the coordinated expression of many virulence genes during bacterial infection of host cells. PrfA activity is controlled by multiple regulatory mechanisms, including an apparent requirement for either the presence of a cofactor or some form of posttranslational modification that regulates the activation of PrfA. In this study, we describe the identification and characterization of a novel PrfA mutation that re...

  9. Reduction of relative centrifugal forces increases growth factor release within solid platelet-rich-fibrin (PRF)-based matrices: a proof of concept of LSCC (low speed centrifugation concept).

    Science.gov (United States)

    El Bagdadi, K; Kubesch, A; Yu, X; Al-Maawi, S; Orlowska, A; Dias, A; Booms, P; Dohle, E; Sader, R; Kirkpatrick, C J; Choukroun, J; Ghanaati, S

    2017-03-21

    Purpose The present study evaluated the platelet distribution pattern and growth factor release (VEGF, TGF-β1 and EGF) within three PRF (platelet-rich-fibrin) matrices (PRF, A-PRF and A-PRF+) that were prepared using different relative centrifugation forces (RCF) and centrifugation times. Materials and methods immunohistochemistry was conducted to assess the platelet distribution pattern within three PRF matrices. The growth factor release was measured over 10 days using ELISA. Results The VEGF protein content showed the highest release on day 7; A-PRF+ showed a significantly higher rate than A-PRF and PRF. The accumulated release on day 10 was significantly higher in A-PRF+ compared with A-PRF and PRF. TGF-β1 release in A-PRF and A-PRF+ showed significantly higher values on days 7 and 10 compared with PRF. EGF release revealed a maximum at 24 h in all groups. Toward the end of the study, A-PRF+ demonstrated significantly higher EGF release than PRF. The accumulated growth factor releases of TGF-β1 and EGF on day 10 were significantly higher in A-PRF+ and A-PRF than in PRF. Moreover, platelets were located homogenously throughout the matrix in the A-PRF and A-PRF+ groups, whereas platelets in PRF were primarily observed within the lower portion. ​Discussion the present results show an increase growthfactor release by decreased RCF. However, further studies must be conducted to examine the extent to which enhancing the amount and the rate of released growth factors influence wound healing and biomaterial-based tissue regeneration. ​Conclusion These outcomes accentuate the fact that with a reduction of RCF according to the previously LSCC (described low speed centrifugation concept), growth factor release can be increased in leukocytes and platelets within the solid PRF matrices.

  10. fMRI repetition suppression: neuronal adaptation or stimulus expectation?

    Science.gov (United States)

    Larsson, Jonas; Smith, Andrew T

    2012-03-01

    Measurements of repetition suppression with functional magnetic resonance imaging (fMRI adaptation) have been used widely to probe neuronal population response properties in human cerebral cortex. fMRI adaptation techniques assume that fMRI repetition suppression reflects neuronal adaptation, an assumption that has been challenged on the basis of evidence that repetition-related response changes may reflect unrelated factors, such as attention and stimulus expectation. Specifically, Summerfield et al. (Summerfield C, Trittschuh EH, Monti JM, Mesulam MM, Egner T. 2008. Neural repetition suppression reflects fulfilled perceptual expectations. Nat Neurosci. 11:1004-1006) reported that the relative frequency of stimulus repetitions and non-repetitions influenced the magnitude of repetition suppression in the fusiform face area, suggesting that stimulus expectation accounted for most of the effect of repetition. We confirm that stimulus expectation can significantly influence fMRI repetition suppression throughout visual cortex and show that it occurs with long as well as short adaptation durations. However, the effect was attention dependent: When attention was diverted away from the stimuli, the effects of stimulus expectation completely disappeared. Nonetheless, robust and significant repetition suppression was still evident. These results suggest that fMRI repetition suppression reflects a combination of neuronal adaptation and attention-dependent expectation effects that can be experimentally dissociated. This implies that with an appropriate experimental design, fMRI adaptation can provide valid measures of neuronal adaptation and hence response specificity.

  11. Screening of methods for preparing PRF and A-PRF in rabbits%兔PRF、A-PRF制备方法的筛选

    Institute of Scientific and Technical Information of China (English)

    毛俊丽; 孙勇; 赵峰; 陈红亮

    2016-01-01

    目的 筛选制备兔富血小板纤维蛋白(PRF)和改良型富血小板纤维蛋白(A-PRF)凝胶的方法,为后续动物实验及临床研究提供参考.方法 选择17种离心方法制备兔PRF凝胶,16种离心方法制备兔A-PRF凝胶,通过光镜观察,与人标准方法制备的PRF、A-PRF对比分析,筛选与人PRF、A-PRF镜下微观结构最接近的兔PRF、A-PRF制备方法.结果 各组离心产物表现不一,凝块结构分层、活细胞数量范围、纤维蛋白排列各不相同.其中3250 r/min离心10 min制备的兔PRF,2000 r/min离心24 min制备的兔A-PRF分别与人PRF、A-PRF镜下微观组织学结构最为接近.结论 3250 r/min离心10 min和2000 r/min离心24 min分别可作为制备兔PRF和A-PRF的最佳条件.

  12. Soliton repetition rate in a silicon-nitride microresonator

    CERN Document Server

    Bao, Chengying; Wang, Cong; Jaramillo-Villegas, Jose A; Leaird, Daniel E; Qi, Minghao; Weiner, Andrew M

    2016-01-01

    The repetition rate of a Kerr comb comprising a single soliton in an anomalous dispersion silicon nitride microcavity is measured as a function of pump frequency tuning. The contributions from the Raman soliton self-frequency shift (SSFS) and from thermal effects are evaluated both experimentally and theoretically; the SSFS is found to dominate the changes in repetition rate. The relationship between the changes in repetition rate and pump frequency detuning is found to be independent of the nonlinearity coefficient and dispersion of the cavity. Modeling of the repetition rate change by using the generalized Lugiato-Lefever equation is discussed; the Kerr shock is found to have only a minor effect on repetition rate for cavity solitons with duration down to ~50 fs.

  13. Soliton repetition rate in a silicon-nitride microresonator.

    Science.gov (United States)

    Bao, Chengying; Xuan, Yi; Wang, Cong; Jaramillo-Villegas, Jose A; Leaird, Daniel E; Qi, Minghao; Weiner, Andrew M

    2017-02-15

    The repetition rate of a Kerr comb composed of a single soliton in an anomalous group velocity dispersion silicon-nitride microcavity is measured as a function of pump frequency. By comparing operation in the soliton and non-soliton states, the contributions from the Raman soliton self-frequency shift (SSFS) and the thermal effects are evaluated; the SSFS is found to dominate the changes in the repetition rate, similar to silica cavities. The relationship between the changes in the repetition rate and the pump frequency detuning is found to be independent of the nonlinearity coefficient and dispersion of the cavity. Modeling of the repetition rate change by using the generalized Lugiato-Lefever equation is discussed; the Kerr shock is found to have only a minor effect on repetition rate for cavity solitons with duration down to ∼50  fs.

  14. 低频重复经颅磁刺激治疗半侧空间忽略的临床研究%Effect of Low Frequency Repetitive Transcranial Magnetic Stimulation on Unilateral Spatial Neglect

    Institute of Scientific and Technical Information of China (English)

    何静杰; 刘丽旭; 公维军; 杨宇琦; 毕晓辉; 崔丽华; 杨凌雨; 山磊; 胡雪艳

    2011-01-01

    Objective To explore the effect of low frequency repetitive transranial magnetic stimulation (Rtms) on unilateral spatial neglect (USN). Methods 40 stroke patients with USN were divided into treatment group (n=20) and control group (n=20). Patients in the treatment group were treated with low frequency Rtms for 2 weeks. The USN degree of these groups were evaluated before and after the treatment. Results There was no significant difference of USN degree between these groups before the treatment (.P>0.05); Compared with the control group, the treatment group improved significantly after the treatment (P0.05). Conclusion USN induced by stroke could be improved obviously through low frequency Rtms.%目的 探讨低频重复经颅磁刺激治疗半侧空间忽略症的临床疗效。方法 将40例脑卒中所致半侧空间忽略症患者分为治疗组及对照组各20例,并对治疗组进行为期2周的低频重复经颅磁刺激治疗。在治疗前后,采用半侧卒间忽略评估量表分别对两组患者进行评定。结果 治疗前,两组患者半侧空间忽略程度无显著性差异(P>0.05);治疗后,治疗组半侧卒间忽略程度较对照组改善(P<0.05);治疗后,治疗组中重度异常率较治疗前明显降低(P<0.05),对照组无显著性差异(P>0.05)。结论 通过低频重复经颅磁刺激治疗,脑卒中所致半侧空间忽略程度明显改善。

  15. Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation☆

    Science.gov (United States)

    Shin, Joonho; Yang, EunJoo; Cho, KyeHee; Barcenas, Carmelo L; Kim, Woo Jin; Min, Yusun; Paik, Nam-Jong

    2012-01-01

    Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects. PMID:25745455

  16. Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation

    Institute of Scientific and Technical Information of China (English)

    Joonho Shin; EunJoo Yang; KyeHee Cho; Carmelo L Barcenas; Woo Jin Kim; Yusun Min; Nam-Jong Paik

    2012-01-01

    Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects.

  17. PRF Cross-Cultural Psychological Study of Lithuanian Students, Teachers, and Special Education Teachers

    Science.gov (United States)

    Illovsky, Michael E.; Gintiliene, Grazina; Bulotaite, Laima; Rickman, Jacqueline; Belekiene, Marijona; Janowitz, Karl

    2008-01-01

    The Personality Research Form (PRF) was used to study the psychological traits of Lithuanian college of education students, teachers, and special education teachers. A sample of American college students was also used for comparison. Chi-square results indicated no statistical differences among the groups. Interpretations of the lack of…

  18. Comparison between PRP, PRGF and PRF: lights and shadows in three similar but different protocols.

    Science.gov (United States)

    Giannini, S; Cielo, A; Bonanome, L; Rastelli, C; Derla, C; Corpaci, F; Falisi, G

    2015-01-01

    The main goal of the modern surgery is to get a low invasiveness and a high rate of clinical healing: in the last years, it has been introduced the concept of a "regenerative surgery", and many techniques has been widely described in the literature. The most used are PRP, PRGF and PRF techniques. Aim of this research is to compare the three protocol of PRP, PRF and PRGF in their essential features, so to suggest to the practitioners the best blood product to use in the regenerative surgery. Among the advantages that shows the PRF, compared to PRP and PRGF, we can cite a greater simplicity of production for the absence of manipulation that leads to a reduced possibility of alteration of the protocol due to an error of the operator. The special texture of the PRF and its biological features shows clearly an interesting surgical versatility and all the characteristics that can support a faster tissues regeneration and high-quality clinical outcomes.

  19. Epistatic selection and coadaptation in the Prf resistance complex of wild tomato.

    Science.gov (United States)

    Grzeskowiak, Lukasz; Stephan, Wolfgang; Rose, Laura E

    2014-10-01

    Natural selection imposed by pathogens is a strong and pervasive evolutionary force structuring genetic diversity within their hosts' genomes and populations. As a model system for understanding the genomic impact of host-parasite coevolution, we have been studying the evolutionary dynamics of disease resistance genes in wild relatives of the cultivated tomato species. In this study, we investigated the sequence variation and evolutionary history of three linked genes involved in pathogen resistance in populations of Solanum peruvianum (Pto, Fen, and Prf). These genes encode proteins, which form a multimeric complex and together activate defense responses. We used standard linkage disequilibrium, as well as partitioning of linkage disequilibrium components across populations and correlated substitution analysis to identify amino acid positions that are candidates for coevolving sites between Pto/Fen and Prf. These candidates were mapped onto known and predicted structures of Pto, Fen and Prf to visualize putative coevolving regions between proteins. We discuss the functional significance of these coevolving pairs in the context of what is known from previous structure-function studies of Pto, Fen and Prf.

  20. The Impact of Accelerated Right Prefrontal High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Cue-Reactivity: An fMRI Study on Craving in Recently Detoxified Alcohol-Dependent Patients.

    Science.gov (United States)

    Herremans, Sarah C; Van Schuerbeek, Peter; De Raedt, Rudi; Matthys, Frieda; Buyl, Ronald; De Mey, Johan; Baeken, Chris

    2015-01-01

    In alcohol-dependent patients craving is a difficult-to-treat phenomenon. It has been suggested that high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) may have beneficial effects. However, exactly how this application exerts its effect on the underlying craving neurocircuit is currently unclear. In an effort to induce alcohol craving and to maximize detection of HF-rTMS effects to cue-induced alcohol craving, patients were exposed to a block and event-related alcohol cue-reactivity paradigm while being scanned with fMRI. Hence, we assessed the effect of right dorsolateral prefrontal cortex (DLPFC) stimulation on cue-induced and general alcohol craving, and the related craving neurocircuit. Twenty-six recently detoxified alcohol-dependent patients were included. First, we evaluated the impact of one sham-controlled stimulation session. Second, we examined the effect of accelerated right DLPFC HF-rTMS treatment: here patients received 15 sessions in an open label accelerated design, spread over 4 consecutive days. General craving significantly decreased after 15 active HF-rTMS sessions. However, cue-induced alcohol craving was not altered. Our brain imaging results did not show that the cue-exposure affected the underlying craving neurocircuit after both one and fifteen active HF-rTMS sessions. Yet, brain activation changes after one and 15 HF-rTMS sessions, respectively, were observed in regions associated with the extended reward system and the default mode network, but only during the presentation of the event-related paradigm. Our findings indicate that accelerated HF-rTMS applied to the right DLPFC does not manifestly affect the craving neurocircuit during an alcohol-related cue-exposure, but instead it may influence the attentional network.

  1. Repetitive frequency electromagnetic pulse simulator based on inductive adding technique%基于感应叠加技术的重复频率电磁脉冲模拟器

    Institute of Scientific and Technical Information of China (English)

    于成大; 徐笑娟; 罗进; 何山红; 冯德仁

    2012-01-01

    The development and experiment of a small bounded wave simulator are introduced, including the development of the double exponential repetitive frequency pulse source based on the hydrogen thyratron inductive-adder, the design of output coaxial shielding structure, the calculation of the field distribution of the output transformer, the development of the small flat-plate radiator, and the calculation and simulation about the working space E-field of the radiator. The preliminary measurement results of the working space E-field of the radiator are also presented. The experiment results show that the E-field in the working space of the radiator space accords with the linear superposition principle, even if there are differences between the parameters of thyratrons and between the parameters of grid trigger clocks.%介绍了小型平板型有界波模拟器的研制和实验,包括基于氢闸流管感应叠加技术的双指数波重频脉冲源的研制、输出同轴屏蔽结构的设计与输出变压器磁场分布的计算、小型平板型辐射器的设计及工作区内电场的计算与仿真,给出了辐射器工作区内电场初步测量的结果.实验结果表明:即使在感应叠加单元的氢闸流管器件和栅极触发时钟的参数存在差异的情况下,辐射器的工作区内电场基本上符合线性叠加原则.

  2. Comprehensive transcript profiling of Pto- and Prf-mediated host defense responses to infection by Pseudomonas syringae pv. tomato.

    Science.gov (United States)

    Mysore, Kirankumar S; Crasta, Oswald R; Tuori, Robert P; Folkerts, Otto; Swirsky, Peter B; Martin, Gregory B

    2002-11-01

    The disease resistance gene Pto encodes a serine/threonine protein kinase that confers resistance in tomato to Pseudomonas syringae pv. tomato strains that express the effector protein AvrPto. Pto-mediated resistance to bacterial speck disease also requires Prf, a protein with leucine-rich repeats and a putative nucleotide-binding site, although the role of Prf in the defense pathway is not known. We used GeneCalling, an open-architecture, mRNA-profiling technology, to identify genes that are either induced or suppressed in leaves 4 h after bacterial infection in the Pto- and Prf-mediated tomato-Pseudomonas(avrPto) interaction. Over 135 000 individual cDNA fragments representing an estimated 90% of the transcripts expressed in tomato leaves were examined and 432 differentially expressed genes were identified. The genes encode over 25 classes of proteins including 11 types of transcription factors and many signal transduction components. Differential expression of 91% of the genes required both Pto and Prf. Interestingly, differential expression of 32 genes did not require Pto but was dependent on Prf. Thus, our data support a role for Prf early in the Pto pathway and indicate that Prf can also function as an independent host recognition determinant of bacterial infection. Comprehensive expression profiling of the Pto-mediated defense response allows the development of many new hypotheses about the molecular basis of resistance to bacterial speck disease.

  3. 单核细胞增生性李斯特菌prfA基因缺失株的构建及其生物学特性%Construction and characterization of Listeria monocytogenes ΔprfA mutant strains

    Institute of Scientific and Technical Information of China (English)

    白春光; 殷月兰; 贾艳艳; 付红; 高云飞; 焦新安

    2011-01-01

    [目的]单核细胞增生性李斯特菌(Lm)是人兽共患李斯特菌病的病原菌,其致病性与调控因子PrfA蛋白作用下毒力基因的表达有着密切关系,本文初步探讨了PrfA蛋白对细菌毒力因子的调控作用.[方法]利用同源重组技术对血清型分别为1/2a和4b的LM4、F4636进行prfA基因的敲除,并构建其回复突变株,对获得的突变株LM4ΔprfA、F4636ΔprfA进行生物学特性研究.[结果]实验结果表明:两株缺失株的溶血活性丧失、回复突变株的溶血活性得到恢复,突变株还丧失磷脂酶活性,黏附和侵袭特性显著下降(P<0.05),对BALB/c小鼠的半数致死剂量提高了105个数量级.[结论]由此表明,PrfA蛋白对hly、plcB、inl家族基因的表达及细菌毒力具有重要的调控作用.prfA基因缺失株的构建为进一步研究PrfA蛋白的调控功能提供了材料,为研究其在Lm致病性中的作用奠定了基础.%[Objective] Listeria monocytogenes ( Lm) is an important pathogen that can cause serious listeriosis in humans and animals. The pathogenicity of Lm has a close relationship with the PrfA protein regulating the expression of virulence genes. Therefore, we studied the regulation functions of PrfA and its role on Lm's virulence. [Methods] The prfA genes of LM4, serotype l/2a, and F4636, serotype 4b, were deleted by homologous recombination technology, and the biological characteristics of the mutants were further studied. [ Results ] The prfA gene deleted strains LM4△prfA and F4636△prfA and their back mutation strains were successfully constructed. The results show that the hemolysis activity was lost in prfA deleted strains and was recovered in the reverse mutant strains. The prfA deleted strains lost phospholipase activity; their adhesion and invasion ability significantly decreased. Furthermore, their 50% lethal doses ( LD50) were 5 logs higher comparing with wild type strains. [Conclusion] PrfA regulates hly, plcB and inl gene

  4. Novel porcine repetitive elements

    Directory of Open Access Journals (Sweden)

    Nonneman Dan J

    2006-12-01

    Full Text Available Abstract Background Repetitive elements comprise ~45% of mammalian genomes and are increasingly known to impact genomic function by contributing to the genomic architecture, by direct regulation of gene expression and by affecting genomic size, diversity and evolution. The ubiquity and increasingly understood importance of repetitive elements contribute to the need to identify and annotate them. We set out to identify previously uncharacterized repetitive DNA in the porcine genome. Once found, we characterized the prevalence of these repeats in other mammals. Results We discovered 27 repetitive elements in 220 BACs covering 1% of the porcine genome (Comparative Vertebrate Sequencing Initiative; CVSI. These repeats varied in length from 55 to 1059 nucleotides. To estimate copy numbers, we went to an independent source of data, the BAC-end sequences (Wellcome Trust Sanger Institute, covering approximately 15% of the porcine genome. Copy numbers in BAC-ends were less than one hundred for 6 repeat elements, between 100 and 1000 for 16 and between 1,000 and 10,000 for 5. Several of the repeat elements were found in the bovine genome and we have identified two with orthologous sites, indicating that these elements were present in their common ancestor. None of the repeat elements were found in primate, rodent or dog genomes. We were unable to identify any of the replication machinery common to active transposable elements in these newly identified repeats. Conclusion The presence of both orthologous and non-orthologous sites indicates that some sites existed prior to speciation and some were generated later. The identification of low to moderate copy number repetitive DNA that is specific to artiodactyls will be critical in the assembly of livestock genomes and studies of comparative genomics.

  5. 低频重复经颅磁刺激在帕金森病康复治疗中的应用价值%The application of low frequency repetitive transcranial magnetic stimulation in rehabilitation of Parkinson's disease patients

    Institute of Scientific and Technical Information of China (English)

    吴卓华; 崔立谦; 许启锋; 林杰; 刘磊; 吴宜娟; 谭红愉; 李少明; 邵明

    2013-01-01

    Objective To explore the application value of low frequency repetitive transcranial magnetic stimulation (rTMS) in Parkinson's disease (PD) patients and electrophysiological research.Methods Fifty-six PD patients treated in the Department of Neurology of our hospital from September 2010 to September 2012 were randomly divided into 2 groups,group A (N =28) and group B (N =28).Patients in group A were given conventional drug treatment and rehabilitation training,while patients in group B were given low frequency rTMS on the basis of conventional drug treatment and rehabilitation training.After 3 weeks,the scores of Unified Parkinson's Disease Rating Scale (UPDRS),resting threshold (RT),cortical latent period,nerve root latent period,central motor conduction time (CMCT) and the incidence of adverse reactions were compared between 2 groups.Results After intervention,the emotion,ability of daily living and motor function of patients in group B was obviously improved,and the scores of UPDRS in group B were significantly lower than that in group A (P < 0.05,for all).The RT,cortical latent period and CMCT in group B were longer than that in group A (P < 0.05,for all).The incidence of adverse reactions of 2 groups was not obviously different (P > 0.05).Conclusion The effect of low frequency rTMS in the treatment for PD is evident,safe and reliable,and with less adverse reaction.It can be used as a noninvasive physical treatment measure for PD.%目的 探讨低频重复经颅磁刺激在帕金森病康复治疗中的应用价值及电生理学研究方法.方法 选择56例符合纳入条件的帕金森病患者,随机分为常规药物治疗和康复训练组(A组)及常规治疗辅助低频重复经颅磁刺激治疗组(B组),连续治疗3周后评价两组患者统一帕金森病评价量表(UPDRS)评分、静息阈值、皮质潜伏期、神经根潜伏期、中枢运动传导时间和不良反应发生率.结果 与A组相比,低频重复经颅磁刺激治疗后B

  6. 人眼安全高重频窄脉宽单模全光纤激光器特性研究%Characteristics of eye-safe high repetition frequency narrow pulse width single mode all fiber laser

    Institute of Scientific and Technical Information of China (English)

    张鑫; 刘源; 贺岩; 杨燕; 侯霞; 陈卫标

    2015-01-01

    介绍了基于主振荡功率放大结构的人眼安全全光纤激光器。首先对比了电光调制及直接调制产生的种子激光在百kHz重复频率、纳秒级脉冲宽度的激光放大器中优缺点,综合系统需求选择直接调制方式;之后对窄脉冲单模放大中出现的脉冲分裂现象进行了研究,选用10μm纤芯的双包层铒镱共掺光纤,仅通过两级放大即获得了1550 nm,重复频率为200 kHz,脉冲宽度为4.07 ns,峰值功率为1.02 kW的单模激光输出。具有结构紧凑、稳定可靠的特点,可用于三维视频激光雷达。%An eye-safe, all fiber, single mode, fiber laser based on master oscillator power amplifier configuration was presented. The advantages and disadvantages were compared between using a directly modulated diode laser and an electro-optical modulated continuous-wave diode as seed laser in sub-Mega Hertz, nanosecond fiber amplifier. The main restriction of power scaling in nanosecond fiber laser was pulse split. 10μm core double cladding erbium ytterbium co-doped fiber was employed as gain fiber of power amplifier. The directly modulated seed laser was then amplified by only two stage amplifiers. Finally, a peak power of 1.02 kW with 4.07 ns pulse duration at 200 kHz pulse repetition frequency with single-mode output was obtained and it is applicable in three dimensional video imaging lidar system.

  7. Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: A comparative DNS study

    KAUST Repository

    Luong, Minh Bau

    2016-10-11

    The ignition characteristics of a lean primary reference fuel (PRF)/air mixture under reactivity controlled compression ignition (RCCI) and stratified charge compression ignition (SCCI) conditions are investigated using 2-D direct numerical simulations (DNSs) with a 116-species reduced mechanism of PRF oxidation. For RCCI combustion, n-heptane and iso-octane are used as two different reactivity fuels and the corresponding global PRF number is PRF50 which is also used as a single fuel for SCCI combustion. The 2-D DNSs of RCCI/SCCI combustion are performed by varying degree of fuel stratification, r, and turbulence intensity, u\\', at different initial mean temperature, T , with negatively-correlated T-r fields. It is found that in the low- and intermediate-temperature regimes, the overall combustion of RCCI cases occurs earlier and its mean heat release rate (HRR) is more distributed over time than those of the corresponding SCCI cases. This is because PRF number stratification, PRF\\', plays a dominant role and T\\' has a negligible effect on the overall combustion within the negative temperature coefficient (NTC) regime. In the high-temperature regime, however, the difference between RCCI and SCCI combustion becomes marginal because the ignition of the PRF/air mixture is highly-sensitive to T\\' rather than PRF\\' and ϕ(symbol)\\'. The Damköhler number analysis verifies that the mean HRR is more distributed over time with increasing r because the portion of deflagration mode of combustion becomes larger with increasing fuel stratification. Finally, it is found that the overall combustion of both RCCI and SCCI cases becomes more like the 0-D ignition with increasing u\\' due to the homogenization of initial mixture by turbulent mixing.

  8. Localized Optimization and Effectiveness Analysis of Medium PRF Airborne Pulse Doppler Radars in the Turkish Air Force

    Science.gov (United States)

    2011-09-01

    Clutter STT Single Target Tracker TWS Track-While-Scan xvi THIS PAGE INTENTIONALLY LEFT BLANK xvii ACKNOWLEDGEMENTS First of all, I would...radar: • Single Target Tracker ( STT ) • Automatic Detection and Tracking (ADT) • Track-While-Scan (TWS) • Phased array tracker • Imaging radar...601–611, April 2006. [33] E. J. Hughes and C. M. Alabaster, “Medium PRF radar PRF optimisation using evolutionary algorithms ,” Proceedings of the

  9. Shortening of subjective visual intervals followed by repetitive stimulation.

    Directory of Open Access Journals (Sweden)

    Fuminori Ono

    Full Text Available Our previous research demonstrated that repetitive tone stimulation shortened the perceived duration of the preceding auditory time interval. In this study, we examined whether repetitive visual stimulation influences the perception of preceding visual time intervals. Results showed that a time interval followed by a high-frequency visual flicker was perceived as shorter than that followed by a low-frequency visual flicker. The perceived duration decreased as the frequency of the visual flicker increased. The visual flicker presented in one hemifield shortened the apparent time interval in the other hemifield. A final experiment showed that repetitive tone stimulation also shortened the perceived duration of preceding visual time intervals. We concluded that visual flicker shortened the perceived duration of preceding visual time intervals in the same way as repetitive auditory stimulation shortened the subjective duration of preceding tones.

  10. The changing of the guard: the Pto/Prf receptor complex of tomato and pathogen recognition.

    Science.gov (United States)

    Ntoukakis, Vardis; Saur, Isabel M L; Conlan, Brendon; Rathjen, John P

    2014-08-01

    One important model for disease resistance is the Prf recognition complex of tomato, which responds to different bacterial effectors. Prf incorporates a protein kinase called Pto as its recognition domain that mimics effector virulence targets, and activates resistance after interaction with specific effectors. Recent findings show that this complex is oligomeric, and reveal how this impacts mechanism. Oligomerisation brings two or more kinases into proximity, where they can phosphorylate each other after effector perception. Effector attack on one kinase activates another in trans, constituting a molecular trap for the effector. Oligomerisation of plant resistance proteins may be a general concept that broadens pathogen recognition and restricts the ability of pathogens to evolve virulence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Effect of leukocyte- and platelet-rich fibrin (L-PRF) on bone regeneration: a study in rabbits.

    Science.gov (United States)

    Knapen, Michel; Gheldof, Damien; Drion, Pierre; Layrolle, Pierre; Rompen, Eric; Lambert, France

    2015-01-01

    The positive effect of leukocyte- and platelet-rich fibrin (L-PRF) on osteogenesis has been widely described in vitro. However, clinical and preclinical studies are very little and controversial in demonstrating a significant beneficial effect of L-PRF in bone regeneration. The goal of the present study was to compare the potential effect of L-PRF in a standardized model. A total of 72 hemispheres were implanted on the calvaria of 18 rabbits and filled with three different space fillers: L-PRF, bovine hydroxyapatite (BHA), BHA + L-PRF, and an empty hemisphere was used as control. Six rabbits were sacrificed at three distinct time points: 1 week, 5 weeks, and 12 weeks. Histological and histomorphometrical analyses were carried out. At the early phase of bone regeneration (1 week), from a descriptive analysis, a higher proportion of connective tissue colonized the regeneration chamber in the two groups containing BHA particles. Nevertheless, no statistical differences were found within the four groups in terms of bone quantity and quality at each timepoint (p = .3623). According to the present study, L-PRF does not seem to provide any additional effect on the kinetics, quality, and quantity of bone in the present model of guided bone regeneration. © 2013 Wiley Periodicals, Inc.

  12. The tomato Prf complex is a molecular trap for bacterial effectors based on Pto transphosphorylation.

    Science.gov (United States)

    Ntoukakis, Vardis; Balmuth, Alexi L; Mucyn, Tatiana S; Gutierrez, Jose R; Jones, Alexandra M E; Rathjen, John P

    2013-01-01

    The major virulence strategy of phytopathogenic bacteria is to secrete effector proteins into the host cell to target the immune machinery. AvrPto and AvrPtoB are two such effectors from Pseudomonas syringae, which disable an overlapping range of kinases in Arabidopsis and Tomato. Both effectors target surface-localized receptor-kinases to avoid bacterial recognition. In turn, tomato has evolved an intracellular effector-recognition complex composed of the NB-LRR protein Prf and the Pto kinase. Structural analyses have shown that the most important interaction surface for AvrPto and AvrPtoB is the Pto P+1 loop. AvrPto is an inhibitor of Pto kinase activity, but paradoxically, this kinase activity is a prerequisite for defense activation by AvrPto. Here using biochemical approaches we show that disruption of Pto P+1 loop stimulates phosphorylation in trans, which is possible because the Pto/Prf complex is oligomeric. Both P+1 loop disruption and transphosphorylation are necessary for signalling. Thus, effector perturbation of one kinase molecule in the complex activates another. Hence, the Pto/Prf complex is a sophisticated molecular trap for effectors that target protein kinases, an essential aspect of the pathogen's virulence strategy. The data presented here give a clear view of why bacterial virulence and host recognition mechanisms are so often related and how the slowly evolving host is able to keep pace with the faster-evolving pathogen.

  13. The tomato Prf complex is a molecular trap for bacterial effectors based on Pto transphosphorylation.

    Directory of Open Access Journals (Sweden)

    Vardis Ntoukakis

    2013-01-01

    Full Text Available The major virulence strategy of phytopathogenic bacteria is to secrete effector proteins into the host cell to target the immune machinery. AvrPto and AvrPtoB are two such effectors from Pseudomonas syringae, which disable an overlapping range of kinases in Arabidopsis and Tomato. Both effectors target surface-localized receptor-kinases to avoid bacterial recognition. In turn, tomato has evolved an intracellular effector-recognition complex composed of the NB-LRR protein Prf and the Pto kinase. Structural analyses have shown that the most important interaction surface for AvrPto and AvrPtoB is the Pto P+1 loop. AvrPto is an inhibitor of Pto kinase activity, but paradoxically, this kinase activity is a prerequisite for defense activation by AvrPto. Here using biochemical approaches we show that disruption of Pto P+1 loop stimulates phosphorylation in trans, which is possible because the Pto/Prf complex is oligomeric. Both P+1 loop disruption and transphosphorylation are necessary for signalling. Thus, effector perturbation of one kinase molecule in the complex activates another. Hence, the Pto/Prf complex is a sophisticated molecular trap for effectors that target protein kinases, an essential aspect of the pathogen's virulence strategy. The data presented here give a clear view of why bacterial virulence and host recognition mechanisms are so often related and how the slowly evolving host is able to keep pace with the faster-evolving pathogen.

  14. MIMICRY, DIFFERENCE AND REPETITION

    Directory of Open Access Journals (Sweden)

    Marcelo Mendes de Souza

    2008-07-01

    Full Text Available This article addresses Homi K. Bhabha’s concept of mimicry in a broader context, other than that of cultural studies and post-colonial studies, bringing together other concepts, such as that of Gilles Deleuze in Difference and repetition, among other texts, and other names, such as Silviano Santiago, Jorge Luís Borges, Franz Kafka and Giorgio Agamben. As a partial conclusion, the article intends to oppose Bhabha’s freudian-marxist view to Five propositions on Psychoanalysis (1973, Gilles Deleuze’s text about Psychoanalysis published right after his book The Anti-Oedipus.

  15. A numerical study of HCCI combustion of PRF mixtures compared with PCCI experiments

    Energy Technology Data Exchange (ETDEWEB)

    Van Wijngaarden, B.

    2008-09-15

    For automotive applications engines that produce less soot and NOx are desired. For that reason the Homogeneous Charge Compression Ignition (HCCI) principle is investigated all over the world, including the technical universities of Berlin (TUB) and Eindhoven. HCCI combines a homogeneous charge, as in an Otto engine with the autoignition principle of a Diesel engine. Auto-ignition and almost instantaneous combustion of a homogeneous charge leads to almost zero soot emissions, lower temperatures and thereby much lower NOx emissions. Auto-ignition timing however, depends on the fuel and its chemistry, which is very sensitive to the applied conditions, being pressure, temperature, equivalence ratio ({phi}), dilution with EGR and engine speed. To study this systematically a 0D model with PRF fuels is used (Primary Reference Fuels are n-heptane, iso-octane and mixtures). A 0D model is chosen because it excludes complex fluid dynamics and thereby allows the use of detailed combustion mechanisms, describing the (PRF) chemistry. Furthermore the model has a multi zone possibility to evaluate in-homogeneities of the charge. PRF fuels are used because n-heptane (CN=55) auto-ignites like a diesel and iso-octane (ON=100) approaches gasoline. For the PRF chemistry three combustion mechanisms were selected, of which two were validated showing a great difference in predicted ignition delay and sensitivity to changes. Furthermore the model was validated with a PCCI (Premixed Charge Compression Ignition) experiment. Extensive comparisons with PCCI experiments from the TUB showed that when the moment of injection was used to launch the chemistry in the model, only the Soyhan mechanism predicted the ignition close to the experimental ignition moment. Furthermore a 7 zone model was able to approach the experimental CO and NOX emissions. Finally none of the mechanisms was able to predict a pressure profile similar to the experiments. More zones and or a better mechanism could improve

  16. Choukroun's platelet-rich fibrin (PRF) stimulates in vitro proliferation and differentiation of human oral bone mesenchymal stem cell in a dose-dependent way.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Doglioli, Pierre; de Peppo, Giuseppe M; Del Corso, Marco; Charrier, Jean-Baptiste

    2010-03-01

    Choukroun's platelet-rich fibrin (PRF) is an autologous leukocyte- and platelet-rich fibrin biomaterial. The purpose of this study was to analyse the in vitro effects of PRF on human bone mesenchymal stem cells (BMSC), harvested in the oral cavity after preimplant endosteal stimulation. BMSCs from primary cultures were cultivated with or without a PRF membrane originating from the same donor as for the cells, in proliferation or osteoblastic differentiation conditions. After 7 days, the PRF membranes were removed. A series of cultures were performed using 2 PRF membranes, in order to measure the dose-dependent effect. Cell counts, cytotoxicity tests, alkaline phosphatase (ALP) activity quantification, Von Kossa staining and mineralisation nodules counts were performed at 3, 7, 14, 21 and 28 days. A last independent series was carried on up to 14 days, for a morphological scanning electron microscope (SEM) observation. PRF generated a significant stimulation of the BMSC proliferation and differentiation throughout the experimental period. This effect was dose-dependent during the first weeks in normal conditions, and during the whole experimentation in differentiation conditions. The cultures without PRF in differentiation conditions did not rise above the degree of differentiation of the cultures in normal conditions with 1 or 2 PRF up to the 14th and 28th day, respectively. The SEM culture analysis at day 14 allowed to show the mineralisation nodules which were more numerous and more structured in the groups with PRF compared to the control groups. This double contradictory proliferation/differentiation result may be due to the numerous components of PRF, particularly the presence of leukocytes: any culture with PRF is in fact a coculture with leukocytes. It could be the source of differential geographic regulation processes within the culture. The combination of oral BMSC and PRF might offer many potential clinical and biotechnological applications, and deserves

  17. In-vitro release pharmacokinetics of amikacin, teicoplanin and polyhexanide in a platelet rich fibrin?layer (PRF)?a laboratory evaluation of a modern, autologous wound treatment

    OpenAIRE

    Knafl, Daniela; Thalhammer, Florian; Vossen, Matthias G.

    2017-01-01

    Objectives Platelet rich fibrin (PRF) is an autologous fibrin glue, produced from patients' blood, which, besides intraoperative use, has applications in the treatment of infected wounds. The combination with antimicrobial agents results in a prolonged antibacterial effect allowing for wound dressing change intervals of seven days even in infected wounds. The aim of this study was to evaluate release kinetics of amikacin, teicoplanin or polyhexanide from a PRF-layer. Methods PRF mixed with te...

  18. The N-terminal domain of the tomato immune protein Prf contains multiple homotypic and Pto kinase interaction sites.

    Science.gov (United States)

    Saur, Isabel Marie-Luise; Conlan, Brendon Francis; Rathjen, John Paul

    2015-05-01

    Resistance to Pseudomonas syringae bacteria in tomato (Solanum lycopersicum) is conferred by the Prf recognition complex, composed of the nucleotide-binding leucine-rich repeats protein Prf and the protein kinase Pto. The complex is activated by recognition of the P. syringae effectors AvrPto and AvrPtoB. The N-terminal domain is responsible for Prf homodimerization, which brings two Pto kinases into close proximity and holds them in inactive conformation in the absence of either effector. Negative regulation is lost by effector binding to the catalytic cleft of Pto, leading to disruption of its P+1 loop within the activation segment. This change is translated through Prf to a second Pto molecule in the complex. Here we describe a schematic model of the unique Prf N-terminal domain dimer and its interaction with the effector binding determinant Pto. Using heterologous expression in Nicotiana benthamiana, we define multiple sites of N domain homotypic interaction and infer that it forms a parallel dimer folded centrally to enable contact between the N and C termini. Furthermore, we found independent binding sites for Pto at either end of the N-terminal domain. Using the constitutively active mutant ptoL205D, we identify a potential repression site for Pto in the first ∼100 amino acids of Prf. Finally, we find that the Prf leucine-rich repeats domain also binds the N-terminal region, highlighting a possible mechanism for transfer of the effector binding signal to the NB-LRR regulatory unit (consisting of a central nucleotide binding and C-terminal leucine-rich repeats). © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. The N-Terminal Domain of the Tomato Immune Protein Prf Contains Multiple Homotypic and Pto Kinase Interaction Sites*

    Science.gov (United States)

    Saur, Isabel Marie-Luise; Conlan, Brendon Francis; Rathjen, John Paul

    2015-01-01

    Resistance to Pseudomonas syringae bacteria in tomato (Solanum lycopersicum) is conferred by the Prf recognition complex, composed of the nucleotide-binding leucine-rich repeats protein Prf and the protein kinase Pto. The complex is activated by recognition of the P. syringae effectors AvrPto and AvrPtoB. The N-terminal domain is responsible for Prf homodimerization, which brings two Pto kinases into close proximity and holds them in inactive conformation in the absence of either effector. Negative regulation is lost by effector binding to the catalytic cleft of Pto, leading to disruption of its P+1 loop within the activation segment. This change is translated through Prf to a second Pto molecule in the complex. Here we describe a schematic model of the unique Prf N-terminal domain dimer and its interaction with the effector binding determinant Pto. Using heterologous expression in Nicotiana benthamiana, we define multiple sites of N domain homotypic interaction and infer that it forms a parallel dimer folded centrally to enable contact between the N and C termini. Furthermore, we found independent binding sites for Pto at either end of the N-terminal domain. Using the constitutively active mutant ptoL205D, we identify a potential repression site for Pto in the first ∼100 amino acids of Prf. Finally, we find that the Prf leucine-rich repeats domain also binds the N-terminal region, highlighting a possible mechanism for transfer of the effector binding signal to the NB-LRR regulatory unit (consisting of a central nucleotide binding and C-terminal leucine-rich repeats). PMID:25792750

  20. Repetition in Waiting for Godot

    Institute of Scientific and Technical Information of China (English)

    李想; 魏妍

    2015-01-01

    Waiting for Godot is one of the most famous plays written by Samuel Barclay Beckett, and also is the founding work of“Theatre of the Absurd”. In the drama, repetitive phenomena shed light on the whole construction considerably. All the charac-ters were helpless and unthinking. Their dialogues were simple, nonsense and repetitive. Two scenes were cyclical. Repetition was used subtly in order to express the theme of the play, showing mental crisis after depravation of WWII.

  1. Behavior of Gingival Fibroblasts on Titanium Implant Surfaces in Combination with either Injectable-PRF or PRP

    Directory of Open Access Journals (Sweden)

    Xuzhu Wang

    2017-02-01

    Full Text Available Various strategies have been employed to speed tissue regeneration using bioactive molecules. Interestingly, platelet concentrates derived from a patient’s own blood have been utilized as a regenerative strategy in recent years. In the present study, a novel liquid platelet formulation prepared without the use of anti-coagulants (injectable-platelet-rich fibrin, i-PRF was compared to standard platelet-rich plasma (PRP with gingival fibroblasts cultured on smooth and roughened titanium implant surfaces. Standard PRP and i-PRF (centrifuged at 700 rpm (60× g for 3 min were compared by assays for fibroblast biocompatibility, migration, adhesion, proliferation, as well as expression of platelet-derived growth factor (PDGF, transforming growth factor-β (TGF-β, collagen1 (COL1 and fibronectin (FN. The results demonstrate that i-PRF induced significantly higher cell migration, as well as higher messenger RNA (mRNA levels of PDGF, TGF-β, collagen1 and fibronectin when compared to PRP. Furthermore, collagen1 synthesis was highest in the i-PRF group. These findings demonstrate that liquid platelet concentrates can be formulated without the use of anticoagulants and present much translational potential for future research. Future animal and clinical trials are now necessary to further investigate the potential of utilizing i-PRF for soft tissue regenerative protocols in combination with various biomaterials.

  2. Behavior of Gingival Fibroblasts on Titanium Implant Surfaces in Combination with either Injectable-PRF or PRP.

    Science.gov (United States)

    Wang, Xuzhu; Zhang, Yufeng; Choukroun, Joseph; Ghanaati, Shahram; Miron, Richard J

    2017-02-04

    Various strategies have been employed to speed tissue regeneration using bioactive molecules. Interestingly, platelet concentrates derived from a patient's own blood have been utilized as a regenerative strategy in recent years. In the present study, a novel liquid platelet formulation prepared without the use of anti-coagulants (injectable-platelet-rich fibrin, i-PRF) was compared to standard platelet-rich plasma (PRP) with gingival fibroblasts cultured on smooth and roughened titanium implant surfaces. Standard PRP and i-PRF (centrifuged at 700 rpm (60× g) for 3 min) were compared by assays for fibroblast biocompatibility, migration, adhesion, proliferation, as well as expression of platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), collagen1 (COL1) and fibronectin (FN). The results demonstrate that i-PRF induced significantly higher cell migration, as well as higher messenger RNA (mRNA) levels of PDGF, TGF-β, collagen1 and fibronectin when compared to PRP. Furthermore, collagen1 synthesis was highest in the i-PRF group. These findings demonstrate that liquid platelet concentrates can be formulated without the use of anticoagulants and present much translational potential for future research. Future animal and clinical trials are now necessary to further investigate the potential of utilizing i-PRF for soft tissue regenerative protocols in combination with various biomaterials.

  3. Behavior of Gingival Fibroblasts on Titanium Implant Surfaces in Combination with either Injectable-PRF or PRP

    Science.gov (United States)

    Wang, Xuzhu; Zhang, Yufeng; Choukroun, Joseph; Ghanaati, Shahram; Miron, Richard J.

    2017-01-01

    Various strategies have been employed to speed tissue regeneration using bioactive molecules. Interestingly, platelet concentrates derived from a patient’s own blood have been utilized as a regenerative strategy in recent years. In the present study, a novel liquid platelet formulation prepared without the use of anti-coagulants (injectable-platelet-rich fibrin, i-PRF) was compared to standard platelet-rich plasma (PRP) with gingival fibroblasts cultured on smooth and roughened titanium implant surfaces. Standard PRP and i-PRF (centrifuged at 700 rpm (60× g) for 3 min) were compared by assays for fibroblast biocompatibility, migration, adhesion, proliferation, as well as expression of platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), collagen1 (COL1) and fibronectin (FN). The results demonstrate that i-PRF induced significantly higher cell migration, as well as higher messenger RNA (mRNA) levels of PDGF, TGF-β, collagen1 and fibronectin when compared to PRP. Furthermore, collagen1 synthesis was highest in the i-PRF group. These findings demonstrate that liquid platelet concentrates can be formulated without the use of anticoagulants and present much translational potential for future research. Future animal and clinical trials are now necessary to further investigate the potential of utilizing i-PRF for soft tissue regenerative protocols in combination with various biomaterials. PMID:28165420

  4. Proteomic profiling of Rhizobium tropici PRF 81: identification of conserved and specific responses to heat stress.

    Science.gov (United States)

    Gomes, Douglas Fabiano; Batista, Jesiane Stefânia da Silva; Schiavon, Aline Luiza; Andrade, Diva Souza; Hungria, Mariangela

    2012-05-30

    Rhizobium tropici strain PRF 81 (= SEMIA 4080) has been used in commercial inoculants for application to common-bean crops in Brazil since 1998, due to its high efficiency in fixing nitrogen, competitiveness against indigenous rhizobial populations and capacity to adapt to stressful tropical conditions, representing a key alternative to application of N-fertilizers. The objective of our study was to obtain an overview of adaptive responses to heat stress of strain PRF 81, by analyzing differentially expressed proteins when the bacterium is grown at 28°C and 35°C. Two-dimensional gel electrophoresis (2DE) revealed up-regulation of fifty-nine spots that were identified by MALDI-TOF/TOF-TOF. Differentially expressed proteins were associated with the functional COG categories of metabolism, cellular processes and signaling, information storage and processing. Among the up-regulated proteins, we found some related to conserved heat responses, such as molecular chaperones DnaK and GroEL, and other related proteins, such as translation factors EF-Tu, EF-G, EF-Ts and IF2. Interestingly, several oxidative stress-responsive proteins were also up-regulated, and these results reveal the diversity of adaptation mechanisms presented by this thermotolerant strain, suggesting a cross-talk between heat and oxidative stresses. Our data provide valuable protein-expression information relevant to the ongoing genome sequencing of strain PRF 81, and contributes to our still-poor knowledge of the molecular determinants of the thermotolerance exhibited by R. tropici species.

  5. Understanding maximal repetitions in strings

    CERN Document Server

    Crochemore, Maxime

    2008-01-01

    The cornerstone of any algorithm computing all repetitions in a string of length n in O(n) time is the fact that the number of runs (or maximal repetitions) is O(n). We give a simple proof of this result. As a consequence of our approach, the stronger result concerning the linearity of the sum of exponents of all runs follows easily.

  6. In vitro effects of Choukroun's PRF (platelet-rich fibrin) on human gingival fibroblasts, dermal prekeratinocytes, preadipocytes, and maxillofacial osteoblasts in primary cultures.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Diss, Antoine; Odin, Guillaume; Doglioli, Pierre; Hippolyte, Marie-Pascale; Charrier, Jean-Baptiste

    2009-09-01

    The objective of this study was to analyze the effects of Choukroun's PRF (platelet-rich fibrin), a leucocyte and platelet concentrate clinically usable as fibrin membrane or clot, on human primary cultures of gingival fibroblasts, dermal prekeratinocytes, preadipocytes, and maxillofacial osteoblasts. For the proliferation study, these cells were cultivated with or without a PRF membrane originating from the same donor as for the cells. For osteoblasts and fibroblasts, dose-dependent effect was assessed (using 2 membranes). Cell counts and cytotoxicity tests were performed at 3, 7, 14, and 21 days, and even 28 days for osteoblasts. More osteoblast cultures were prepared in differentiation conditions according to 3 modalities (without PRF, with PRF, with PRF the first day and differentiation medium applied only after the first week of culture). Osteoblast differentiation was analyzed using Von Kossa staining and alkaline phosphatase, DNA and total cell proteins dosage. PRF induced a significant and continuous stimulation of proliferation in all cell types. It was dose dependent during all the experiment with osteoblasts, but only on day 14 with fibroblasts. Moreover, PRF induced a strong differentiation in the osteoblasts, whatever the culture conditions. The analysis of osteoblast cultures in differentiation conditions with PRF, using light and scanning electron microscopy, revealed a starting mineralization process in the PRF membrane itself after 14 days. Moreover, PRF leucocytes seemed to proliferate and interact with osteoblasts. Cultures with PRF are always cocultures with leucocytes. These "chaperone leucocytes" could be the source of differential geographic regulation within the culture and explain the double contradictory effect proliferation/differentiation observed on osteoblasts.

  7. Clinical efficacy of different frequency repetitive transcranial magnetic stimulation for tardive dyskinesia%不同频率重复经颅磁刺激治疗迟发性运动障碍的疗效研究

    Institute of Scientific and Technical Information of China (English)

    张保华; 谭云龙; 王志仁; 张五芳; 杨甫德; 卞清涛; 韩笑乐; 江述荣; 杨贵刚

    2014-01-01

    目的 探讨不同频率重复经颅磁刺激(rTMS)治疗迟发性运动障碍(TD)的疗效.方法 长期服用抗精神病药所致迟发性运动障碍的精神分裂症患者,随机给予1 Hz(低频)和10 Hz(高频)的rTMS治疗4周,每周治疗5d.中间休息2周.分别在治疗前和治疗后进行异常不自主运动评定量表(AIMS)和锥体外系副反应量表(RESES)评定,评分变化作为疗效和副反应评价指标.结果 低频组经rTMS治疗后只有上肢的不自主运动改善[治疗前(2.6±1.0)分,治疗后(1.8±1.1)分],差异有统计学意义(P<0.05).高频组经rTMS治疗后多个量表分下降,其中上肢[治疗前(1.9±1.2)分,治疗后(0.8±0.9)分]、唇及口周[治疗前(1.0±0.8)分,治疗后(0.3±0.5)分]和舌[治疗前(2.6±0.9)分,治疗后(1.7±0.9)分]及总量表分[治疗前(7.7±3.0)分,治疗后(4.2±1.7)分]评分治疗前后差异有统计学意义(P< 0.05或<0.01).另外,两组间在下肢和总量表分减分率方面差异有统计学意义(P<0.05).结论 rTMS治疗TD有效,且高频(10 Hz)组治疗TD效果好.%Objective To investigate the effect of different frequency of repetitive transcranial magnetic stimulation (rTMS)on tardive dyskinesia (TD).Methods Schizophrenia combined with antipsychotic-induced TD were screened.All patients were planed to receive 1Hz or 10Hz rTMS for 4 weeks in which two weeks' break was inserted at end of 2nd weekend.The curative effect and side effects were assessed by abnormal involuntary movement scale(AIMS) and rating scale for extrapyramidal side effects(RSESE) respectively at before and after treatment.Results In the 1Hz group,only Involuntary movements of the upper extremities were improved after rTMS treatment (before treatment 2.6± 1.0,after treatment 1.8 ± 1.1),the difference was statistically significant (P<0.05).But in 10Hz group,upper extremities (before treatment 1.9 ± 1.2,0.8 ± 0.9 after treatment),mouth (before treatment 1.0±0.8,after treatment 0.3±0

  8. Early Bone Formation at a Femur Defect Using CGF and PRF Grafts in Adult Dogs: A Comparative Study.

    Science.gov (United States)

    Park, Hyun-Chun; Kim, Su-Gwan; Oh, Ji-Su; You, Jae-Seek; Kim, Jae-Sung; Lim, Sung-Chul; Jeong, Mi-Ae; Kim, Jin-Son; Jung, Chan; Kwon, Young-Sun; Ji, Hyeok

    2016-06-01

    The purpose of this study was to compare the predictability of new bone formation using an autologous concentrated growth factor (CGF) graft alone and platelet graft alone. Four bony defects of 8 mm were formed, and 3.7- × 10-mm implants were placed in the right femur. The platelet-rich fibrin (PRF), CGF, and synthetic bone were grafted to the bone defect area. Enzyme linked immunosorbent assay quantitative analysis and microscopic analysis of the fibrinogen structure were performed. At 4 weeks, the comparisons of each experimental group showed a significant difference between the CGF group and the synthetic bone graft group. When comparing the CGF and allograft material groups, the allograft group showed significantly more new bone formation. In the case of vascular endothelial growth factor, CGF had 1.5 times more than PRF. CGF showed a fibrinogen structure with a constant diameter. When applied to a clinical case, CGF is predicted to show better results than PRF.

  9. Perceptual Repetition Blindness Effects

    Science.gov (United States)

    Hochhaus, Larry; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    The phenomenon of repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to post-perceptual processes such as memory retrieval and/or reporting biases. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is, indeed, open to such objections. Here we investigate RB using a "single-frame" paradigm introduced by Johnston and Hale (1984) in which memory demands are minimal. Subjects made only a single judgement about whether one masked target word was the same or different than a post-target probe. Confidence ratings permitted use of signal detection methods to assess sensitivity and bias effects. In the critical condition for RB a precue of the post-target word was provided prior to the target stimulus (identity precue), so that the required judgement amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was either an unrelated word or a dummy.

  10. Investigative effects of low frequency repetitive transcranial magnetic stimulation combined with drugs on obstinate auditory hallucinations and cognitive function in patients with schizophrenia%低频重复经颅刺激联合药物干预对精神分裂症患者顽固性幻听和认知功能的影响效果探析

    Institute of Scientific and Technical Information of China (English)

    马继东; 潘赞; 田洪伟; 王朝

    2015-01-01

    Objective To explore the clinical value of low frequency repetitive transcranial magnetic stimulation in improving obstinate auditory hallucinations and cognitive function in patients with schizophrenia. Methods According to visiting order number, 128 patients with schizophrenia were divided into control group and observation group.The observation group was treated by low frequency repetitive transcranial magnetic stimulation combined with risperidone, the control group was treated with risperidone.Before and after treatment, the patients were evaluated, by auditory hallucinations rating scale( AHRS) and assessment of verbal fluency and trail making were performed in patients.Results There was no significant difference in AHRS scores, VFT scores and trail making between the two groups before treatment (P>0.05).After treatment, the AHRS scores in the observation group were lower than that in the control group, the VFT scores in the observation group were higher than that in the control group, with statistical significance between two groups (P0.05).治疗后,观察组AHRS评分低于对照组,VFT评分则升高明显,差异具统计学意义( P<0.05). 结论 低频重复经颅刺激联合药物干预可较好的改善精神分裂症患者顽固性幻听,以及语言方面的认知功能.

  11. Two-dimensional proteome reference map of Rhizobium tropici PRF 81 reveals several symbiotic determinants and strong resemblance with agrobacteria.

    Science.gov (United States)

    Gomes, Douglas Fabiano; Batista, Jesiane Stefania da Silva; Torres, Adalgisa Ribeiro; de Souza Andrade, Diva; Galli-Terasawa, Lygia Vitoria; Hungria, Mariangela

    2012-03-01

    Rhizobium tropici strain PRF 81 is used in commercial inoculants for common-bean crops in Brazil because of its high efficiency in nitrogen fixation and, as in other strains belonging to this species, its tolerance of environmental stresses, representing a useful biological alternative to chemical nitrogen fertilizers. In this study, a proteomic reference map of PRF 81 was obtained by two-dimensional gel electrophoresis and MALDI-TOF/TOF-TOF mass spectrometry. In total, 115 spots representing 109 different proteins were successfully identified, contributing to a better understanding of the rhizobia-legume symbiosis and supporting, at proteomics level, a strong resemblance with agrobacteria.

  12. 激光重频对脉冲非稳腔TEA CO2激光远场传输特性的影响分析%Analysis of far-field characteristics with repetition frequency of TEA CO2 laser

    Institute of Scientific and Technical Information of China (English)

    汤伟; 郭劲; 邵俊峰; 郭汝海; 王挺峰

    2013-01-01

    为了研究TEA CO2激光重复频率对远场光束特性的影响,首先采用有限元方法计算了不同重复频率下反射镜的温度场和热变形分布,然后采用协方差矩阵法对镜面热变形进行了Zernike拟合,最后结合衍射的角谱传播理论和功率谱反演法分析了不同重频TEA CO2激光经过内光路热畸变作用后的远场光束特性。研究表明:在净吸收能量相同的情况下,随着重复频率的增大,反射镜的温度逐渐升高,热变形量逐渐增大,经过内光路热畸变作用后,远场光束的Sr和平均能量密度Ed逐渐减小,参数逐渐增大,光束质量逐渐变差;对于TEA CO2激光,重频为300 Hz的Ed值仅为10 Hz的40%,远场光束的峰值光强下降了43%,光斑展宽了近60%。文中的研究结果为TEA CO2激光发射系统的优化设计提供可靠的依据。%In order to study the influence of TEA CO2 laser repetition frequency on far-field beam quality, the temperature field and thermal deformation distribution of the mirror were calculated firstly by the finite element analysis of thermodynamics instantaneous method with TEA CO2 laser irradiation of different repetition frequencies. Then, mirror thermal distortion was fitted by Zernike polynomials. Finally, far-field characteristics of different repetition frequencies TEA CO2 laser were obtained by the angular spectrum propagation theory of diffraction. The theory and simulation results show that with the increasing of laser repetition frequency, the mirror temperature and thermal deformation are gradually increasing. After thermal deformation effect, Sr and the average energy density Ed decrease, and parameter gradually increases in the far field. Comparing with 10 Hz, Ed of 300 Hz decreases 40%, peak power in the far field decreases 43% and beam waist broadens 60%. When the laser repetition frequency is greater than 100 Hz,due to the appearance of peaks and valleys on the mirror, the far

  13. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part III: leucocyte activation: a new feature for platelet concentrates?

    Science.gov (United States)

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. In this third article, we investigate the immune features of this biomaterial. During PRF processing, leucocytes could also secrete cytokines in reaction to the hemostatic and inflammatory phenomena artificially induced in the centrifuged tube. We therefore undertook to quantify 5 significant cell mediators within platelet poor plasma supernatant and PRF clot exudate serum: 3 proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha), an antiinflammatory cytokine (IL-4), and a key growth promoter of angiogenesis (VEGF). Our data are correlated with that obtained in plasma (nonactivated blood) and in sera (activated blood). These initial analyses revealed that PRF could be an immune regulation node with inflammation retrocontrol abilities. This concept could explain the reduction of postoperative infections when PRF is used as surgical additive.

  14. A comparative study of platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) on the effect of proliferation and differentiation of rat osteoblasts in vitro.

    Science.gov (United States)

    He, Ling; Lin, Ye; Hu, Xiulian; Zhang, Yu; Wu, Hui

    2009-11-01

    The purpose of this study was to evaluate the effect of biologic characteristics of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) on proliferation and differentiation of rat osteoblasts. Blood samples were collected from 14 healthy volunteers (7 male) with a mean age of 23.2 +/- 2.24 years. PRP and PRF were prepared with standard protocols. The exudates of PRP and PRF were collected at the time points of 1, 7, 14, 21, and 28 days. The levels of platelet-derived growth factor AB (PDGF-AB) and transforming growth factor beta1 (TGF-beta1) were quantified in PRP and PRF. Then the exudates of PRP and PRF were used to culture rat calvaria osteoblasts. The biologic characteristics of osteoblasts were analyzed in vitro for 14 days. PRP released the highest amounts of TGF-beta1 and PDGF-AB at the first day, followed by significantly decreased release at later time points. PRF released the highest amount of TGF-beta1 at day 14 and the highest amount of PDGF-AB at day 7. Exudates of PRP collected at day 1 and exudates of PRF collected at day 14 expressed maximum alkaline phosphatase (ALP) activity, though no significance was shown. Cells treated with exudates of PRF collected at day 14 reached peak mineralization significantly more than both negative control and positive control groups. PRF is superior to PRP, from the aspects of expression of ALP and induction of mineralization. PRF released autologous growth factors gradually and expressed stronger and more durable effect on proliferation and differentiation of rat osteoblasts than PRP in vitro.

  15. Avoidance Eclipse Using Alterable PRF Method Designing for HPRF Radar Seeker%高重频雷达导引头变 PRF 抗遮挡方法设计

    Institute of Scientific and Technical Information of China (English)

    何华兵; 李文龙; 杨士义

    2015-01-01

    We proposed an avoidance eclipse method using alterable PRF for HPRF radar seeker to solve the problem that the ambiguous range information cannot be used directly to avoid eclipse. Firstly,the PRFs in limited range were analyzed and a couple of PRFs could avoid eclipse were selected. Secondly, two switch methods were designed according to whether the air-borne could provide precise initial distance or not. Lastly,the selected couple of PRFs were used to work based on the two switch methods. The result shows that the proposed method has a good avoidance eclipse performance.%针对高重频 PD 雷达测距模糊,不能直接利用距离信息抗距离遮挡的问题,提出了一种高重频雷达导引头变PRF 抗遮挡方法;对限定频率范围内的 PRF 进行分析,根据优选策略确定一组具备抗遮挡能力的 PRF,针对载机能否提供较精确的初始装订距离,分别设计不同的 PRF 切换方式,由导引头软件控制优选 PRF 组按照不同的方式切换工作,完成抗遮挡任务;仿真试验结果表明:提出的方法具有较好的抗遮挡性能。

  16. GrayQbTM Single-Faced Version 2 (SF2) Hanford Plutonium Reclamation Facility (PRF) deployment report

    Energy Technology Data Exchange (ETDEWEB)

    Plummer, J. R. [Savannah River Site (SRS), Aiken, SC (United States); Immel, D. M. [Savannah River Site (SRS), Aiken, SC (United States); Serrato, M. G. [Savannah River Site (SRS), Aiken, SC (United States); Dalmaso, M. J. [Savannah River Site (SRS), Aiken, SC (United States); Shull, D. J. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-11-18

    The Savannah River National Laboratory (SRNL) in partnership with CH2M Plateau Remediation Company (CHPRC) deployed the GrayQbTM SF2 radiation imaging device at the Hanford Plutonium Reclamation Facility (PRF) to assist in the radiological characterization of the canyon. The deployment goal was to locate radiological contamination hot spots in the PRF canyon, where pencil tanks were removed and decontamination/debris removal operations are on-going, to support the CHPRC facility decontamination and decommissioning (D&D) effort. The PRF canyon D&D effort supports completion of the CHPRC Plutonium Finishing Plant Decommissioning Project. The GrayQbTM SF2 (Single Faced Version 2) is a non-destructive examination device developed by SRNL to generate radiation contour maps showing source locations and relative radiological levels present in the area under examination. The Hanford PRF GrayQbTM Deployment was sponsored by CH2M Plateau Remediation Company (CHPRC) through the DOE Richland Operations Office, Inter-Entity Work Order (IEWO), DOE-RL IEWO- M0SR900210.

  17. Combination of platelet rich fibrin, hydroxyapatite and PRF membrane in the management of large inflammatory periapical lesion.

    Science.gov (United States)

    Shivashankar, Vasundara Yayathi; Johns, Dexton Antony; Vidyanath, S; Sam, George

    2013-05-01

    Periapical inflammatory lesion is the local response of bone around the apex of tooth that develops after the necrosis of the pulp tissue or extensive periodontal disease. The final outcome of the nature of wound healing after endodontic surgery can be repair or regeneration depending on the nature of the wound; the availability of progenitor cells; signaling molecules; and micro-environmental cues such as adhesion molecules, extracellular matrix, and associated non-collagenous protein molecules. The purpose of this case report is to add knowledge to the existing literature about the combined use of graft material [platelet rich fibrin (PRF) and hydroxyapatite (HA)] and barrier membrane in the treatment of large periapical lesion. A periapical endodontic surgery was performed on a 45 year old male patient with a swelling in the upper front teeth region and a large bony defect radiologically. The surgical defect was filled with a combination of PRF and HA bone graft crystals. The defect was covered by PRF membrane and sutured. Clinical examination revealed uneventful wound healing. Radiologically the HA crystals have been completely replaced by new bone at the end of 2 years. On the basis of the results obtained in our case report, we hypothesize that the use of PRF in conjunction with HA crystals might have accelerated the resorption of the graft crystals and would have induced the rapid rate of bone formation.

  18. Chemopreventive action of Lygodium flexuosum extract in human hepatoma PLC/PRF/5 and Hep 3B cells.

    Science.gov (United States)

    Wills, P J; Asha, V V

    2009-03-18

    Lygodium flexuosum (Lygodiaceae), a medicinal fern used in Indian traditional medicine against liver disorders. The rationale of the study was to examine whether the n-hexane extract from plant Lygodium flexuosum affects apoptosis on human hepatoma PLC/PRF/5 and Hep 3B cells. Chemopreventive activity of the Lygodium flexuosum extract was determined by MTT assay, annexin-V FITC binding to phosphatidyl serine and cleavage of PARP. Subdiploid condition of cells treated with Lygodium flexuosum was analyzed by flow cytometry. Further, used transiently transfected NF-kappaB reporter in PLC/PRF/5 cells to evaluate the inhibitive effect of Lygodium flexuosum extract. Lygodium flexuosum extract inhibited the cell viability and induced apoptosis in hepatoma cells in a concentration dependent manner as evidenced by apoptotic changes such as flipping of phosphatidyl serine, cleavage of PARP. Cell cycle analysis showed the subG1 apoptotic population in cells treated with higher concentrations of the extract. When activated with exogenous TNF-alpha in transfected hepatoma cells it was observed that NF-kappaB dependent gene expression was inhibited by treatment with Lygodium flexuosum extract in PLC/PRF/5 cells dose-dependently. This investigation suggests that the Lygodium flexuosum extract has antiproliferative and apoptotic activity in both cancer cells and has inhibitive role in TNF-alpha induced NF-kappaB activation in PLC/PRF/5 cells confirms the potential of the extract as a chemopreventive agent.

  19. [Comparative proteomics analysis of extracellular proteins from Listeria monocytogenes and its isogenic prfA deletion mutant].

    Science.gov (United States)

    Yin, Yuelan; Bai, Chunguang; Wang, Guoliang; Jia, Yanyan; Qu, Jin; Fu, Hong; Gao, Yunfei; Jiao, Xin'an

    2013-04-04

    Positive regulatory factor A (PrfA) protein plays a key role in the pathogenicity of Listeria monocytogenes by regulating the expression of virulence genes. We studied the regulation functions of PrfA and its role in Listeria monocytogenes (Lm) virulence. Extracellular proteins were obtained from the supernatants of parental strain LM4 and mutant strain LM4deltaprfA cultured in minimal medium. We used two-dimensional gel electrophoresis and matrix associated laser dissociation/ionization time of flight mass spectrometry (MALDI- TOF-MS) to analyze the differences of secreted proteins between LM4 and LM4deltaprfA. The electrophoresis results show that 31 different spots, 19 spots corresponding 12 proteins were identified by MALDI- TOF-MS. Some virulence related proteins were verified, such as InlC, ActA and LLO. Some new proteins that are regulated by PrfA include D-alanyl-D-alanine carboxypeptidase, dipeptide Glycine and Trytophan (GW) repeat-containing surface protein, transcriptional regulator and some hypothetical proteins with unknown functions. Real-time quantitative PCR was conducted to verify the proteomics results. The mRNA expression level of hly, actA and inlC gene was significantly reduced, and that of D-alanyl-D-alanine carboxypeptidase and GW repeat-containing surface protein's synthesis also had a reduction in LM4deltaprfA strain. PrfA plays key roles on the regulation of genes in LIPI- I and LIPI- II.

  20. Combination of platelet rich fibrin, hydroxyapatite and PRF membrane in the management of large inflammatory periapical lesion

    Directory of Open Access Journals (Sweden)

    Vasundara Yayathi Shivashankar

    2013-01-01

    On the basis of the results obtained in our case report, we hypothesize that the use of PRF in conjunction with HA crystals might have accelerated the resorption of the graft crystals and would have induced the rapid rate of bone formation.

  1. The PAF complex and Prf1/Rtf1 delineate distinct Cdk9-dependent pathways regulating transcription elongation in fission yeast.

    Directory of Open Access Journals (Sweden)

    Jean Mbogning

    Full Text Available Cyclin-dependent kinase 9 (Cdk9 promotes elongation by RNA polymerase II (RNAPII, mRNA processing, and co-transcriptional histone modification. Cdk9 phosphorylates multiple targets, including the conserved RNAPII elongation factor Spt5 and RNAPII itself, but how these different modifications mediate Cdk9 functions is not known. Here we describe two Cdk9-dependent pathways in the fission yeast Schizosaccharomyces pombe that involve distinct targets and elicit distinct biological outcomes. Phosphorylation of Spt5 by Cdk9 creates a direct binding site for Prf1/Rtf1, a transcription regulator with functional and physical links to the Polymerase Associated Factor (PAF complex. PAF association with chromatin is also dependent on Cdk9 but involves alternate phosphoacceptor targets. Prf1 and PAF are biochemically separate in cell extracts, and genetic analyses show that Prf1 and PAF are functionally distinct and exert opposing effects on the RNAPII elongation complex. We propose that this opposition constitutes a Cdk9 auto-regulatory mechanism, such that a positive effect on elongation, driven by the PAF pathway, is kept in check by a negative effect of Prf1/Rtf1 and downstream mono-ubiquitylation of histone H2B. Thus, optimal RNAPII elongation may require balanced action of functionally distinct Cdk9 pathways.

  2. Influence of PRF in the healing of bone and gingival tissues. Clinical and histological evaluations.

    Science.gov (United States)

    Marrelli, M; Tatullo, M

    2013-07-01

    The healing of bone tissues around dental implants is based primarily on a correct osseointegration. Typically, implants stability and peri-implant tissues health are anticipated to decrease during the early weeks of healing; this is followed by an increase in stability. The aim of the present study is to assess a predictable protocol in order to increase the peri-implant tissues maintenance around post-extractive dental implants, thanks to the use of Platelet-Rich Fibrin (PRF) membrane. This is a retrospective observational study of 127 tapered dental implants placed in the immediate post-extraction sites of maxillary bone of 59 patients. Atraumatic dental extraction and flapless implant surgery was performed in all reported cases. The cortical bone position relative to the implant reference point was evaluated at implant placement and 10 to 24 months following implantology. The gap between bone tissue and the implant surface was measured up to a maximum of 3 mm. After placing implants we have filled the surgical site with a PRF gel, so as to fill the gap between bone tissue and the implant surface, and then we have covered the surgical site with a PRF membrane, so as to coat the gap between the alveolar crest and the implant. In all cases, we observed the complete covering of the dental implants, with newly formed soft tissue of variable thickness between 1 and 3 mm. Cortical bone adaptation from the time of implant placement up to 30 months following prosthetic restoration ranged from 0.4 mm to 1.7 mm. Our study showed a series of successful rehabilitations, with post-extraction implantology technique, in 99.8 percent of cases, despite the success rates in the medium and long-term post-extraction implantology reported in the literature range between 92.7 percent and 98.0 percent. Long-term maintenance of crestal bone and the rapid healing of soft tissue dimension with maintenance of peri-implant papilla were observed as outcomes after post-extractive implants

  3. A Naturally Occurring Mutation K220T in the Pleiotropic Activator PrfA of Listeria Monocytogenes Results in a Loss of Virulence Due to Decreasing DNA-Binding Affinity

    Energy Technology Data Exchange (ETDEWEB)

    Velge,P.; Herler, M.; Johansson, J.; Roches, S.; Temoin, S.; Fedorov, A.; Gracieux, P.; Almo, S.; Goebel, W.; Cossart, P.

    2007-01-01

    The sequencing of prfA, encoding the transcriptional regulator of virulence genes, in 26 low-virulence field Listeria monocytogenes strains showed that eight strains exhibited the same single amino-acid substitution: PrfAK220T. These strains exhibited no expression of PrfA-regulated proteins and thus no virulence. This substitution inactivated PrfA, since expression of the PrfAK220T mutant gene in an EGD{Delta}prfA strain did not restore the haemolytic and phosphatidylcholine phospholipase C activities, in contrast to the wild-type prfA gene. The substitution of the lysine at position 220 occurred in the helix H. However, the data showed that the PrfAK220T protein is dimerized just as well as its wild-type counterpart, but does not bind to PrfA-boxes. PrfAK220T did not form a PrfA-DNA complex in electrophoretic mobility shift assays, but low concentrations of CI complexes (PrfAK220T-RNA polymerase-DNA complex) were formed by adding RNA polymerase, suggesting that PrfA interacted with RNA polymerase in solution in the absence of DNA. Formation of some transcriptionally active complexes was confirmed by in vitro runoff transcription assays and quantitative RT-PCR. Crystallographic analyses described the structure of native PrfA and highlighted the key role of allosteric changes in the activity of PrfA and especially the role of the Lys220 in the conformation of the helix-turn-helix (HTH) motif.

  4. Laser radiation frequency conversion in carbon- and cluster-containing plasma plumes under conditions of single and two-color pumping by pulses with a 10-Hz repetition rate

    Science.gov (United States)

    Ganeev, R. A.

    2013-07-01

    This work reviews a series of investigations of different plasma plumes using single- and two-color laser systems that emit femtosecond pulses with a 10-Hz repetition rate. Results of investigation of the resonant enhancement of harmonics in tin plasma with the use of two types of pumps are analyzed, and it is shown that the tuning of the wavelengths of harmonics to ion-resonance levels plays an important role in increasing the conversion efficiency to high-order harmonics of the radiation to be converted. Investigations of different carbon-containing plasma media (carbon nanotubes, graphite, carbon aerogel, etc.) exhibit attractive properties of the nonlinear medium of this type for efficient generation of high-order harmonics. The results of the first experiments on the use of nanoparticles produced directly in the course of laser ablation of metals for increasing the efficiency of harmonics generated in this cluster-containing medium are analyzed. It is shown that new approaches realized in these investigations give hope that the nonlinear optical response of plasma media in the far-ultraviolet range can be further increased.

  5. Platelet Rich Fibrin (P.R.F. in Reconstructive Surgery of Atrophied Maxillary Bones: Clinical and Histological Evaluations

    Directory of Open Access Journals (Sweden)

    Marco Tatullo, Massimo Marrelli, Michele Cassetta, Andrea Pacifici, Luigi Vito Stefanelli, Salvatore Scacco, Gianna Dipalma, Luciano Pacifici, Francesco Inchingolo

    2012-01-01

    Full Text Available Introduction. Maxillary bone losses often require additional regenerative procedures: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF (Platelet Rich Fibrin was tested for the first time in France by Dr. Choukroun.Aim of the present study is to investigate, clinically and histologically, the potential use of PRF, associated with deproteinized bovine bone (Bio-Oss, as grafting materials in pre-implantology sinus grafting of severe maxillary atrophy, in comparison with a control group, in which only deproteinized bovine bone (Bio-Oss was used as reconstructive material.Materials and Methods. 60 patients were recruited using the cluster-sampling method; inclusion criteria were maxillary atrophy with residual ridge < 5mm. The major atrophies in selected patients involved sinus-lift, with a second-look reopening for the implant insertion phase. The used grafting materials were: a Bio-Oss and b amorphous and membranous PRF together with Bio-Oss. We performed all operations by means of piezosurgery in order to reduce trauma and to optimize the design of the operculum on the cortical bone. The reopening of the surgical area was scheduled at 3 different times.Results. 72 sinus lifts were performed with subsequent implants insertions.We want to underline how the histological results proved that the samples collected after 106 days (Early protocol with the adding of PRF were constituted by lamellar bone tissue with an interposed stroma that appeared relaxed and richly vascularized.Conclusions. The use of PRF and piezosurgery reduced the healing time, compared to the 150 days described in literature, favoring optimal bone regeneration. At 106 days, it is already possible to achieve good primary stability of endosseous implants, though lacking of functional loading.

  6. Genetic and molecular requirements for function of the Pto/Prf effector recognition complex in tomato and Nicotiana benthamiana.

    Science.gov (United States)

    Balmuth, Alexi; Rathjen, John P

    2007-09-01

    The Pto gene of tomato (Solanum lycopersicum) confers specific recognition of the unrelated bacterial effector proteins AvrPto and AvrPtoB. Pto resides in a constitutive molecular complex with the nucleotide binding site-leucine rich repeats protein Prf. Prf is absolutely required for specific recognition of both effectors. Here, using stable transgenic lines, we show that expression of Pto from its genomic promoter in susceptible tomatoes was sufficient to complement recognition of Pseudomonas syringae pv. tomato (Pst) bacteria expressing either avrPto or avrPtoB. Pto kinase activity was absolutely required for specific immunity. Expression of the Pto N-myristoylation mutant, pto(G2A), conferred recognition of Pst (avrPtoB), but not Pst (avrPto), although bacterial growth in these lines was intermediate between resistant and susceptible lines. Overexpression of pto(G2A) complemented recognition of avrPto. Transgenic tomato plants overexpressing wild-type Pto exhibited constitutive growth phenotypes, but these were absent in lines overexpressing pto(G2A). Therefore, Pto myristoylation is a quantitative factor for effector recognition in tomato, but is absolutely required for overexpression phenotypes. Native expression of Pto in the heterologous species Nicotiana benthamiana did not confer resistance to P. syringae pv. tabaci (Pta) expressing avrPto or avrPtoB, but recognition of both effectors was complemented by Prf co-expression. Thus, specific resistance conferred solely by Pto in N. benthamiana is an artefact of overexpression. Finally, pto(G2A) did not confer recognition of either avrPto or avrPtoB in N. benthamiana, regardless of the presence of Prf. Thus, co-expression of Prf in N. benthamiana complements many but not all aspects of normal Pto function.

  7. Repetition in English Political Public Speaking

    Institute of Scientific and Technical Information of China (English)

    李红梅

    2010-01-01

    Repetition is frequently used in English political public speaking to make it easy to be remembered and powerful to move the feelings of the public. This paper is intended to analyze the functions of repetition and different levels of repetition to highlight the significance of repetition in English political public speaking and the ability of using it in practice.

  8. The virulence regulator PrfA plays a significant role in the Listeria monocytogenes biofilm formation%毒力基因调控蛋白PrfA促进单核细胞增生李斯特菌生物被膜的形成

    Institute of Scientific and Technical Information of China (English)

    冯飞飞; 张强; 王莉; 冯晓琴; 尹晓蛟; 罗勤

    2011-01-01

    The ability of the foodbome pathogen Listeria monocytogenes to develop biofilm in food-processing environment is a major concern for the food safety, because formation of biofilm facilitates bacteria to survive in the adverse environment and resist desiccation, UV light and treatmentwith antimicrobial and sanitizing agents. However, the molecular mechanism of biofilm formation in L. Monocytogenes has not been fully understood. PrfA is a key transcriptional activator that positively regulates most of the known Hsterial virulence genes expression. In order to explore the role of PrfA on Listeria biofilm development, we compared the abilities of biofilm formation in this study for L. Monocytogenes wild type strains (EGD and EGDe) and their prfA deletion mutants (EGDAp^ and EGDeApr/A), nonpathogenic Listeria innocua, as well as the recombinant strains that can constitutively express PrfA in L. Innocua (LI-pERL3-/r/4*) and in EGDpAprfA {EGDeAprfA-pERL3-prfA*). Our results showed that the wild types of L. Monocytogenes had strong abilities to develop "a network of knitted chains" biofilm structures on polyvinyl chloride microtiter plates, while unstructured biofilm was observed in L. Innocua. Biofilm formation was reduced in L. Monocytogenes mutants lacking PrfA and rescued in the strain with constitutive expression of PrfA. However, PrfA had no impact on L. Innocua biofilm formation. Our results suggest that PrfA plays a significant role only in the L. Monocytogenes biofilm formation but not in L. Innocua. PrfA might indirectly regulate expression of certain genes involving in L. Monocytogenes biofilm formation.%单核细胞增生李斯特菌(Listeria monocytogenes,LM)是重要的革兰氏阳性食源性致病菌,易在食品以及各种食品加工、运输和保藏设备的接触面形成生物被膜,从而具有更强的抗逆性而难以彻底清除,因此成为食品卫生安全的重要隐患.PrfA是LM毒力基因转录表达的重要调控因子,通过比较研

  9. Low frequency (1-Hz), right prefrontal repetitive transcranial magnetic stimulation (rTMS) compared with venlafaxine ER in the treatment of resistant depression: a double-blind, single-centre, randomized study.

    Science.gov (United States)

    Bares, Martin; Kopecek, Miloslav; Novak, Tomas; Stopkova, Pavla; Sos, Peter; Kozeny, Jiri; Brunovsky, Martin; Höschl, Cyril

    2009-11-01

    Previous studies have shown effectiveness of repetitive transcranial magnetic stimulation (rTMS) in the treatment of depression. This double-blind study compared efficacy of l Hz rTMS over the right prefrontal dorsolateral cortex with venlafaxine ER in the treatment of resistant depression. A total of 60 inpatients with depressive disorder (DSM-IV criteria), who previously did not respond to at least one antidepressant treatment, were randomly assigned to 1 Hz rTMS with placebo and venlafaxine ER with sham rTMS for 4 weeks. The primary outcome measure was score change in the Montgomery-Asberg Depression Rating Scale (MADRS). We also used Clinical Global Impression (CGI) and Beck Depressive. Inventory-Short Form (BDI-SF). The response was defined as a >or=50% reduction of MADRS score. There were no significant differences between treatment groups in MADRS (p=0.38), BDI-SF (p=0.56) and CGI (p=0.17) scores from baseline to endpoint. Response rates for rTMS (33%) and venlafaxine (39%) as well as remission (MADRS score

  10. Measuring Repetitive Behaviors as a Treatment Endpoint in Youth with Autism Spectrum Disorder

    Science.gov (United States)

    Scahill, Lawrence; Aman, Michael G.; Lecavalier, Luc; Halladay, Alycia K.; Bishop, Somer L.; Bodfish, James W.; Grondhuis, Sabrina; Jones, Nancy; Horrigan, Joseph P.; Cook, Edwin H.; Handen, Benjamin L.; King, Bryan H.; Pearson, Deborah A.; McCracken, James T.; Sullivan, Katherine Anne; Dawson, Geraldine

    2015-01-01

    Restricted interests and repetitive behaviors vary widely in type, frequency, and intensity among children and adolescents with autism spectrum disorder. They can be stigmatizing and interfere with more constructive activities. Accordingly, restricted interests and repetitive behaviors may be a target of intervention. Several standardized…

  11. Repetition rate continuously tunable 10-GHz picosecond mode-locked fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Fang Wan; Ziyu Wang

    2006-01-01

    A couple of simple-structure phase modulators were used in active mode-locked fiber laser to implement repetition rate continuous tuning. The laser produces pulse as short as 5.7 ps whose repetition rate tuning can cover the spacing of the adjoining order mode-locking frequencies.

  12. Varianish: Jamming with Pattern Repetition

    Directory of Open Access Journals (Sweden)

    Jort Band

    2014-10-01

    Full Text Available In music, patterns and pattern repetition are often regarded as a machine-like task, indeed often delegated to drum Machines and sequencers. Nevertheless, human players add subtle differences and variations to repeated patterns that are musically interesting and often unique. Especially when looking at minimal music, pattern repetitions create hypnotic effects and the human mind blends out the actual pattern to focus on variation and tiny differences over time. Varianish is a musical instrument that aims at turning this phenomenon into a new musical experience for musician and audience: Musical pattern repetitions are found in live music and Varianish generates additional (musical output accordingly that adds substantially to the overall musical expression. Apart from the theory behind the pattern finding and matching and the conceptual design, a demonstrator implementation of Varianish is presented and evaluated.

  13. Improved Temperature Measurement for Permanent MRI System by Using Hybrid PRF/T1 Method%一种在永磁MRI系统上利用混合PRF/T1的改进测温方法

    Institute of Scientific and Technical Information of China (English)

    王雷; 李璟; 朱剑锋; 钟智辉; 陈武凡; 冯衍秋

    2013-01-01

    研究基于混合PRF/T1的测温方法,以提高永磁MRI温度测量的准确度与可靠性.用琼脂凝胶仿真肝脏组织制作体模,将体模放在水浴中加热到65℃,然后置于0.3T永磁MRI系统用翻转角为40°与75°的梯度回波序列进行交替连续扫描,在降温中温度每下降1℃采集一次数据直到36℃.对所采集数据,分别用质子共振频率(PRF)方法、水质子纵向弛豫时间(T1)方法、改进的混合PRF/T1方法计算温度变化,并以酒精温度计测温结果作为参考.比较这3种方法的测温准确度,3d内分别进行3次测温实验,用3次实验结果的变异系数(COV)评价测温方法可重复性.结果表明,仅用PRF或T1方法的测温误差为±6℃,而改进的混合PRF/T1方法的测温误差为±3℃.PRF方法的COV=3.12%,T1方法的COV =7.53%,改进的混合PRF/L方法的COV =2.63%.在永磁MRI系统上采用改进的混合PRF/T1方法比单一用PRF或T1方法的测温准度高且可重复性好,可以更好的满足肿瘤热消融对温度监控的需求.

  14. REPETITIVE CLUSTER-TILTED ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    Zhang Shunhua; Zhang Yuehui

    2012-01-01

    Let H be a finite-dimensional hereditary algebra over an algebraically closed field k and CFm be the repetitive cluster category of H with m ≥ 1.We investigate the properties of cluster tilting objects in CFm and the structure of repetitive clustertilted algebras.Moreover,we generalize Theorem 4.2 in [12](Buan A,Marsh R,Reiten I.Cluster-tilted algebra,Trans.Amer.Math.Soc.,359(1)(2007),323-332.) to the situation of CFm,and prove that the tilting graph KCFm of CFm is connected.

  15. Repetitive elements in parasitic protozoa

    Directory of Open Access Journals (Sweden)

    Clayton Christine

    2010-05-01

    Full Text Available Abstract A recent paper published in BMC Genomics suggests that retrotransposition may be active in the human gut parasite Entamoeba histolytica. This adds to our knowledge of the various types of repetitive elements in parasitic protists and the potential influence of such elements on pathogenicity. See research article http://www.biomedcentral.com/1471-2164/11/321

  16. Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF).

    Science.gov (United States)

    Dohan Ehrenfest, David M; Rasmusson, Lars; Albrektsson, Tomas

    2009-03-01

    The topical use of platelet concentrates is recent and its efficiency remains controversial. Several techniques for platelet concentrates are available; however, their applications have been confusing because each method leads to a different product with different biology and potential uses. Here, we present classification of the different platelet concentrates into four categories, depending on their leucocyte and fibrin content: pure platelet-rich plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; leucocyte- and platelet-rich plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan or GPS PRP; pure plaletet-rich fibrin (P-PRF), such as Fibrinet; and leucocyte- and platelet-rich fibrin (L-PRF), such as Choukroun's PRF. This classification should help to elucidate successes and failures that have occurred so far, as well as providing an objective approach for the further development of these techniques.

  17. Transduction of Repetitive Mechanical Stimuli by Piezo1 and Piezo2 Ion Channels

    Directory of Open Access Journals (Sweden)

    Amanda H. Lewis

    2017-06-01

    Full Text Available Several cell types experience repetitive mechanical stimuli, including vein endothelial cells during pulsating blood flow, inner ear hair cells upon sound exposure, and skin cells and their innervating dorsal root ganglion (DRG neurons when sweeping across a textured surface or touching a vibrating object. While mechanosensitive Piezo ion channels have been clearly implicated in sensing static touch, their roles in transducing repetitive stimulations are less clear. Here, we perform electrophysiological recordings of heterologously expressed mouse Piezo1 and Piezo2 responding to repetitive mechanical stimulations. We find that both channels function as pronounced frequency filters whose transduction efficiencies vary with stimulus frequency, waveform, and duration. We then use numerical simulations and human disease-related point mutations to demonstrate that channel inactivation is the molecular mechanism underlying frequency filtering and further show that frequency filtering is conserved in rapidly adapting mouse DRG neurons. Our results give insight into the potential contributions of Piezos in transducing repetitive mechanical stimuli.

  18. The role of Leucocyte-rich and platelet-rich fibrin (L-PRF) in the treatment of the medication-related osteonecrosis of the jaws (MRONJ).

    Science.gov (United States)

    Cano-Durán, Jorge A; Peña-Cardelles, Juan-Francisco; Ortega-Concepción, Daniel; Paredes-Rodríguez, Víctor M; García-Riart, Mariano; López-Quiles, Juan

    2017-08-01

    For the treatment of the bisphosphonates and other drugs related osteonecrosis of the jaws, currently medication-related osteonecrosis of the jaws (MRONJ), have been established different conservative therapeutic approaches, avoiding surgery except in cases of extreme need. Given the controversy and lack of current consensus regarding MRONJ therapy in patients, new techniques have been developed among which the use of fibrin membranes rich in platelets and leukocytes (L-PRF). The objective of this review is to evaluate whether L-PRF treatment is really effective, as well as the results that can be achieved by this therapeutic alternative. A review of the literature in the PubMed/Medline database of all those studies using L-PRF in the treatment of osteonecrosis using the keywords "Osteonecrosis", "Jaws", "L-PRF" and " Leucocyte-rich platelet-rich fibrin ". The use of L-PRF for the treatment of MRONJ is really effective, especially when it is performed with a simultaneous application of L-PRF and morphogenetic protein-2 (BMP-2), even in patients submitted for long periods of time to therapy with intravenous bisphosphonates. However, success will depend on several factors such as the previous existence of infection or the clinical stage in which the patient is. The current literature demonstrates the effectiveness of the use of L-PRF in osteonecrosis, and it can be considered as a real alternative in the treatment of this entity. However, more clinical studies are needed to really assess this new therapy. Key words:Osteonecrosis, Jaws, L-PRF, Leucocyte-rich platelet-rich fibrin.

  19. A novel C-terminal mutation resulting in constitutive activation of the Listeria monocytogenes central virulence regulatory factor PrfA

    OpenAIRE

    Xayarath, Bobbi; Smart, Jennifer I.; Mueller, Kimberly J.; Freitag, Nancy E.

    2011-01-01

    The environmental bacterium Listeria monocytogenes survives and replicates in a variety of diverse ecological niches that range from the soil to the cytosol of infected mammalian cells. The ability of L. monocytogenes to replicate within an infected host requires the expression of a number of secreted bacterial gene products whose expression is regulated by the transcriptional activator PrfA. PrfA becomes activated following bacterial entry into host cells; however, the mechanism by which thi...

  20. Effect of Platelet Rich Fibrin (PRF) on Peri-implant Soft Tissue and Crestal Bone in One-Stage Implant Placement: A Randomized Controlled Trial.

    Science.gov (United States)

    Boora, Priyanka; Rathee, Manu; Bhoria, Mohaneesh

    2015-04-01

    The viability of Platelet Rich Fibrin (PRF) on enhancement of osseous and associated tissue healing has been substantiated well in literature. However, paucity in the applicability of PRF to enhance peri-implant healing in oral region is not well-corroborated. This prospective study evaluated the effect of Platelet PRF on peri-implant tissue response following one-stage implant placement with non-functional immediate provisionalization in maxillary anterior region. A Prospective, Randomized Controlled Trial (RCT) was conducted across 20 (15 male, 5 Female) systemically healthy subjects with maintainable oral hygiene. Subjects were broadly divided into two groups i.e. Study group (PRF group) and Control group (Non-PRF group). Twenty standard SLA- AB/AE (alumina oxide blasted/acid etched surface treated) tapered threaded dental implants were randomly placed with and without PRF and immediately provisionalized. The subjects were evaluated clinically and radiographically at baseline (at time of implant placement), one month and three month post-operatively for peri-implant soft tissue and crestal bone responses. At 3 months, all implants remained osseointegrated. The mean marginal bone changes were observed from baseline to 3 months in both groups with lesser changes observed in PRF Group. No significant differences in probing depth and bleeding on probing were noted during follow-up. Within the limitations of this study, PRF could be considered as a healing biomaterial with potential beneficial effect on peri-implant tissue and can be used as a therapeutic adjuvant in clinical scenario of one stage, single tooth implant placement procedure in maxillary anterior region.

  1. The Clinical Effect of Low Frequency Repetitive Transcranial Magnetic Stimulation combined with Cognitive Behavioral Therapy in the Treatment of Adolescent Depression%经颅磁刺激联合认知行为疗法治疗青少年抑郁症的临床效果

    Institute of Scientific and Technical Information of China (English)

    王静; 杜红兴

    2016-01-01

    Objective:To study the efficacy of low frequency repetitive transcranial magnetic stimulation combined with cognitive behavioral therapy in the treatment of adolescent depression.Method:135 patients were selected in our hospital from January 2010 to December 2015,they were randomly divided into three groups,45 cases in each group.A group was given only antidepressant sertraline treatment,B group based on the sertraline treatment combined with repetitive transcranial magnetic stimulation treatment,C group based on the use of sertraline treatment combined with repetitive transcranial magnetic stimulation and cognitive behavioral therapy. Result:After treatment 4 weeks,the efficacy in group C was significantly better than that in group A and B (P<0.05),scores of HAMD changed from (28.16±3.95) scores to (17.92±9.86) scores,lower than that in group A and B.Scores of TSCS and PSP in group C were higher than that in other groups.Conclusion:Low frequency repetitive transcranial magnetic stimulation combined with cognitive behavior therapy provide an effective and well-tolerant treatment for depression.%目的:研究探讨重复低频经颅磁刺激联合认知行为疗法治疗青少年抑郁症的临床效果。方法:将2010年1月-2015年12月于本院精神科门诊就诊的患者共135例随机分为A、B、C三组,每组45例,其中A组仅用抗抑郁药物舍曲林治疗,B组在使用舍曲林治疗的基础上联合重复低频经颅磁刺激治疗,C组在使用舍曲林治疗的基础上联合重复低频经颅磁刺激和认知行为疗法。结果:治疗4周后,C组的治疗效果明显优于A、B两组(P<0.05)。C组的HAMD评分从(28.16±3.95)分降至(17.92±9.86)分,显著低于A、B两组,TSCS评分和PSP评分均高于A、B两组。结论:重复低频经颅磁刺激联合认知行为疗法是治疗抑郁症的安全有效的方法。

  2. Guided bone regeneration (GBR) using cortical bone pins in combination with leukocyte- and platelet-rich fibrin (L-PRF).

    Science.gov (United States)

    Toffler, Michael

    2014-03-01

    Two of the fundamental requisites for guided bone regeneration (GBR) are space maintenance and primary soft-tissue closure. Allogeneic cortical bone pins measuring 2 mm in diameter in customized lengths can protect surrounding graft materials, support bioresorbable membrane barriers, and resist wound compression from the overlying soft tissues. In addition, a second-generation platelet concentrate, leukocyte- and platelet-rich fibrin (L-PRF), may be incorporated into the augmentation procedure to provide multiple growth factors, accelerate wound healing, and aid in the maintenance of primary closure over the grafted materials. Highlighting two case reports, this article features a GBR technique that uses bone pins in combination with L-PRF membranes to provide both horizontal and vertical ridge augmentation at severely compromised implant sites.

  3. Establishment of hepatitis E virus infection-permissive and -non-permissive human hepatoma PLC/PRF/5 subclones.

    Science.gov (United States)

    Shiota, Tomoyuki; Li, Tian-Cheng; Yoshizaki, Sayaka; Kato, Takanobu; Wakita, Takaji; Ishii, Koji

    2015-02-01

    PLC/PRF/5 cells show limited permissiveness, meaning that almost all subclones are permissive; however, some subclones do not exhibit permissiveness for hepatitis E virus (HEV) infection. In this study, the single-cell cloning of PLC/PRF/5 was performed and heterogeneous subclones characterized. Notably, the efficiency of intracellular virus replication did not correlate with the permissiveness for HEV infection. However, as well as binding permissive subclones, virus-like particles bound non-permissive subclones on various levels, suggesting that these subclones have some deficiencies in the attachment and entry steps of infection. Our data would be useful for investigating the HEV life cycle. © 2014 The Societies and Wiley Publishing Asia Pty Ltd.

  4. 美国军用规范MIL-PRF-13830B表面疵病要求详解

    Institute of Scientific and Technical Information of China (English)

    王丽荣

    2012-01-01

    以各种不同外形、尺寸、疵病大小的光学零件为例,从表面疵病的标识、量值、换算及判定等各方面对美国军用规范MIL-PRF-13830B进行详细解析,介绍根据美国军用规范MIL-PRF-13830B进行光学零件表面疵病检验与判定的方法。并将该标准与我国国家标准进行对比,重点介绍二者的不同之处。

  5. In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin.

    Science.gov (United States)

    Idelevich, Evgeny A; von Eiff, Christof; Friedrich, Alexander W; Iannelli, Domenico; Xia, Guoqing; Peters, Georg; Peschel, Andreas; Wanninger, Ingrid; Becker, Karsten

    2011-09-01

    Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.

  6. Neural dynamics during repetitive visual stimulation

    Science.gov (United States)

    Tsoneva, Tsvetomira; Garcia-Molina, Gary; Desain, Peter

    2015-12-01

    Objective. Steady-state visual evoked potentials (SSVEPs), the brain responses to repetitive visual stimulation (RVS), are widely utilized in neuroscience. Their high signal-to-noise ratio and ability to entrain oscillatory brain activity are beneficial for their applications in brain-computer interfaces, investigation of neural processes underlying brain rhythmic activity (steady-state topography) and probing the causal role of brain rhythms in cognition and emotion. This paper aims at analyzing the space and time EEG dynamics in response to RVS at the frequency of stimulation and ongoing rhythms in the delta, theta, alpha, beta, and gamma bands. Approach.We used electroencephalography (EEG) to study the oscillatory brain dynamics during RVS at 10 frequencies in the gamma band (40-60 Hz). We collected an extensive EEG data set from 32 participants and analyzed the RVS evoked and induced responses in the time-frequency domain. Main results. Stable SSVEP over parieto-occipital sites was observed at each of the fundamental frequencies and their harmonics and sub-harmonics. Both the strength and the spatial propagation of the SSVEP response seem sensitive to stimulus frequency. The SSVEP was more localized around the parieto-occipital sites for higher frequencies (>54 Hz) and spread to fronto-central locations for lower frequencies. We observed a strong negative correlation between stimulation frequency and relative power change at that frequency, the first harmonic and the sub-harmonic components over occipital sites. Interestingly, over parietal sites for sub-harmonics a positive correlation of relative power change and stimulation frequency was found. A number of distinct patterns in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (15-30 Hz) bands were also observed. The transient response, from 0 to about 300 ms after stimulation onset, was accompanied by increase in delta and theta power over fronto-central and occipital sites, which returned to baseline

  7. Repetition suppression and repetition priming are processing outcomes.

    Science.gov (United States)

    Wig, Gagan S

    2012-01-01

    Abstract There is considerable evidence that repetition suppression (RS) is a cortical signature of previous exposure to the environment. In many instances RS in specific brain regions is accompanied by improvements in specific behavioral measures; both observations are outcomes of repeated processing. In understanding the mechanism by which brain changes give rise to behavioral changes, it is important to consider what aspect of the environment a given brain area or set of areas processes, and how this might be expressed behaviorally.

  8. Production of infectious ferret hepatitis E virus in a human hepatocarcinoma cell line PLC/PRF/5.

    Science.gov (United States)

    Li, Tian-Cheng; Yoshizaki, Sayaka; Yang, Tingting; Kataoka, Michiyo; Nakamura, Tomofumi; Ami, Yasushi; Yuriko, Suzaki; Takeda, Naokazu; Wakita, Takaji

    2016-02-02

    A strain of ferret hepatitis E virus (HEV), sF4370, isolated from an imported ferret was used to inoculate a human hepatocarcinoma cell line, PLC/PRF/5. The virus genome and capsid protein were detected in the cell culture supernatant. Immunofluorescence microscopy indicated that the capsid protein was located in the cytoplasm. The virus particles were purified from the culture supernatant by sucrose gradient ultracentrifugation. The capsid protein with molecular mass of ∼72 kDa was detected in fractions with density of 1.150-1.162 g/cm(3), and particles of ferret HEV was associated with cell membrane. The virus recovered from the supernatant was serially passaged with PLC/PRF/5 cells and had the ability to infect ferrets by oral inoculation, indicating that the ferret HEV grown in PLC/PRF/5 was infectious. The establishment of ferret HEV cell culture system might be useful to understand the life cycle, mechanism of infection and replication of ferret HEV.

  9. [Effects of PRF and released three growth factors on migration of rat adipose tissue-derived stem cells].

    Science.gov (United States)

    Gao, Jie; Wang, Ming-guo; Yang, Shuai; Li, Xiu-mei; Yang, Shi-mao; Li, Xue

    2015-12-01

    To analyze the effects of PRF and released three growth factors on migration of rat adipose tissue-derived stem cells and to investigate the mechanism of migration. The inguinal adipose tissue of rat was excised at aseptic condition to obtain primary ADSCs by enzyme digestion. Multi-directional differentiation was used to identify the ADSCs. PRF membrane was acquired through one time centrifuge. The cell migration was examined by Transwell assay and wound healing assay. The mRNA expression of MMP2 and MT1-MMP was tested by real-time PCR. Statistical analysis was performed using SPSS 13.0 software package. Cell migration test showed that the migration of rat ADSCs in PRF group were significantly higher than those in the negative group(PPRF group than control group (PPRF and three growth factors consistently enhanced the migration of rat ADSCs in a dose-response manner. The migration increase of rat ADSCs may be associated with the up-regulation of MMP2 and MT1-MMP gene expression.

  10. Second-generation platelet concentrate (PRF) as a pulpotomy medicament in a permanent molar with pulpitis: a case report.

    Science.gov (United States)

    Hiremath, H; Saikalyan, S; Kulkarni, S S; Hiremath, V

    2012-01-01

      To discuss the clinical and radiographic success of a pulpotomy with second-generation platelet concentrate (PRF), in a human mature permanent molar tooth.   A 19-year-old female patient reported to the Department of Conservative Dentistry and Endodontics with established pulpitis in tooth 36. The tooth had a carious pulp exposure, with a history of lingering pain. After isolation, caries removal and pulp exposure, pulpotomy with PRF was performed and a permanent restoration was placed immediately. At the first recall (+1 day), no postoperative pain was reported. At 6, 12, 18 and 22 months recall, the tooth responded positively to pulp sensibility tests, and radiographic examination revealed a normal periodontal ligament space. Positive results of this case imply the need for more studies with larger sample sizes and a longer recall period to justify the use of this novel material for the treatment of pulpitis in human permanent molar teeth. Pulpotomy with PRF could be an alternate treatment to mineral trioxide aggregate or other materials in mature permanent teeth with pulpitis. © 2011 International Endodontic Journal.

  11. Asialoglycoprotein receptor facilitates infection of PLC/PRF/5 cells by HEV through interaction with ORF2.

    Science.gov (United States)

    Zhang, Li; Tian, Yabin; Wen, Zhiheng; Zhang, Feng; Qi, Ying; Huang, Weijin; Zhang, Heqiu; Wang, Youchun

    2016-12-01

    Although the biological and epidemiological features of hepatitis E virus (HEV) have been studied extensively in recent years, the mechanism by which HEV infects cells is still poorly understood. In this study, coimmunoprecipitation, pull-down, and ELISA were used to show that the HEV ORF2 protein interacts directly with the ectodomain of both ASGR1 and ASGR2. Susceptibility to HEV correlated positively with the expression level of surface asialoglycoprotein receptor (ASGPR) in cell lines. ASGPR-directed small interfering RNA (siRNA) in HEV-infected PLC/PRF/5 cells had no significant effect on HEV release, suggesting that ASGPR mainly regulates the viral binding and entry steps. Both the purified ASGPR ectodomain and anti-ASGPR antibodies disturbed the binding of HEV to PLC/PRF/5 cells. The classic ASGPR ligands asialofetuin, asialoganglioside, and fibronectin competitively inhibited the binding of HEV to hepatocytes in the presence of calcium. HeLa cell lines stably expressing ASGPR displayed increased HEV-binding capacity, whereas ASGPR-knockout PLC/PRF/5 cell lines had lower HEV-binding capacity. Thus, our study demonstrates that ASGPR is involved in and facilitates HEV infection by binding to ORF2. J. Med. Virol. 88:2186-2195, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Cohesive Function of Lexical Repetition in Text

    Institute of Scientific and Technical Information of China (English)

    张莉; 卢沛沛

    2013-01-01

    Lexical repetition is the most direct form of lexical cohesion,which is the central device for making texts hang together. Although repetition is the most direct way to emphasize,it performs the cohesive effect more apparently.

  13. Repetitive firing properties of medial pontine reticular formation neurones of the rat recorded in vitro.

    Science.gov (United States)

    Gerber, U; Greene, R W; McCarley, R W

    1989-03-01

    1. Intracellularly recorded neurones in nucleus reticularis pontis caudalis of the medial pontine reticular formation (mPRF) in the in vitro slice preparation were analysed for repetitive firing properties in response to intracellularly applied constant-current pulses. 2. Three neuronal classes were defined by this procedure: (1) non-burst neurones, which had only a non-burst firing pattern; (2) low-threshold burst neurones, which had either a low-threshold burst pattern or a non-burst pattern; (3) high-threshold burst neurones, which had either a high-threshold burst pattern or a non-burst pattern. 3. Histological characterization of electrophysiologically identified mPRF neurones with carboxyfluorescein showed no definite morphological difference between the first two classes. There was a trend for low-threshold burst neurones to have larger somata. 4. The low-threshold burst was generated by a slow calcium-dependent low-threshold spike, revealed in the presence of tetrodotoxin. The size of the low-threshold spike and thus the number of fast action potentials in the low-threshold burst was controlled by at least five factors including: activation; inactivation; amplitude of low-threshold conductance available to be activated; delayed outward conductance; and early transient outward conductance. 5. The non-burst pattern examined in both non-burst and low-threshold burst neurones appeared to be controlled primarily by one or more calcium-dependent potassium conductances sensitive to the removal of calcium and tetraethyl-ammonium. In the presence of tetrodotoxin (TTX), the addition of antagonists to calcium-dependent potassium current revealed a slow high-threshold calcium spike which was distinguished from the low-threshold spike by its threshold, lack of inactivation (at potentials negative to -40 mV) and insensitivity to Mg2+. A long-duration after-hyperpolarization (greater than 0.5 s) was not observed in any of these cells. 6. An early transient outward

  14. Photoinduced toxicity of PrF3 and LaF3 nanoparticles

    Science.gov (United States)

    Pudovkin, M. S.; Zelenikhin, P. V.; Krasheninnikova, A. O.; Korableva, S. L.; Nizamutdinov, A. S.; Alakshin, E. M.; Semashko, V. V.; Safiullin, R. A.; Kadirov, M. K.

    2016-10-01

    PrF3 and LaF3 nanoparticles were synthesized by the hydrothermal method. The size distribution of these nanoparticles in the colloidal solution produced was studied by photon correlation spectroscopy. The mean diameter of the nanoparticles was 42 ± 1 nm. During the study of the toxicity of the nanoparticles, the mixture of a colloidal solution of the nanoparticles with cells to be studied was irradiated by 30-mW continuous lasers at wavelengths of 532 and 473 nm. The concentration of salmonella cells in normal saline was 106 cell/mL, while that of nanoparticles was 0.1 g/L. The cell survival percentage was 39, 34, and 20% for the irradiation times of 5, 10, and 15 min, respectively, at an optimal laser radiation power density of 0.4 W/cm at a wavelength of 532 nm. It was ascertained that LaF3 nanoparticles do not possess the property of photoinduced toxicity and the apoptosing effect. Moreover, the property of photoinduced toxicity is not shared by microparticles, in contrast to nanoparticles.

  15. Inhibitory effect of genistein on PLC/PRF5 hepatocellular carcinoma cell line

    Directory of Open Access Journals (Sweden)

    Mehdi Nikbakht Dastjerdi

    2015-01-01

    Full Text Available Background: Natural compounds including flavonoids like genistein (GE are able to inhibit cell proliferation and induce apoptosis. GE is the main representative of these groups. GE inhibits carcinogenic tumors such as colon, stomach, lung, and pancreas tumors. The aim of the present study was to analyze the apoptotic effect of GE in the hepatocellular carcinoma (HCC PLC/PRF5 cell line. Methods: Cells were treated with various doses of GE (1, 5, 10, 25, 50, 75, and 100 μM/L at different times (24, 48, and 72 h and the MTT assay was commonly used. Furthermore, cells were treated with single dose of GE (25 μM at different times and flow cytometry was performed. Results: GE inhibited the growth of liver cancer cells significantly with a time- and dose-dependent manner. The percentage of living cells in GE treatment groups with a concentration of 25 μM at different times were 53, 48 and 47%, respectively (P < 0.001. Result of flow cytometry demonstrated that GE at a 25 μM concentration induces apoptosis significantly in a time-dependent manner. The percentage of apoptotic cells at different times were 44, 56, and 60%, respectively (P < 0.001. Conclusions: GE can significantly inhibit the growth of HCC cells and plays a significant role in apoptosis of this cell line.

  16. UWB SAR实时PRF调整%Real Time Adjustment of PRF in UWB SAR

    Institute of Scientific and Technical Information of China (English)

    李建阳; 常文革; 李悦丽

    2009-01-01

    在超宽带合成孔径雷达(UWB SAR)实时成像中,载机沿航向前向速度误差的影响主要是通过实时调整脉冲重复频率(PRF)来消除的,相对于高波段数据,在相同分辨率条件下,UWB SAR数据对载机前向速度的变化要敏感得多.文中分析了UWB SAR实时PRF调整中的3个因素:方位聚焦的要求、硬件调整PRF的精度以及惯导测鲢精度,得出UWB SAR中PRF调整的精度主要由惯导的测量精度决定.仿真数据分析了UWB SAR实时PRF调整对成像质量的影响以及研究结论的有效性.

  17. Ultra high-speed micromachining of transparent materials using high PRF ultrafast lasers and new resonant scanning systems

    Science.gov (United States)

    Harth, F.; Piontek, M. C.; Herrmann, T.; L'huillier, J. A.

    2016-03-01

    Irradiation of focused laser pulses to transparent materials leads to structural changes and can be used for the fabrication of e.g. LED light guiding components. In these applications both small spot sizes and a high lateral resolution in the μm range are absolutely essential. In order to achieve the industrially required throughput of nearly one million laser markings per second, ultrafast lasers with 100 W of average power and pulse repetition frequencies of several MHz are required. Laser machining of polymers additionally necessitates a wide spatial separation of the markings to avoid heat accumulation effects. Therefore, neither commercially available galvanometer based nor Polygon based scanners with their limited scan speed can be used for beam deflection. In our work, we developed an experimental setup based

  18. Effect of low-frequency repetitive transcranial magnetic stimulation promotes recovery of cognitive function and functional independence in patients with traumatic brain injury%低频重复经颅磁刺激对脑外伤患者认知功能和功能独立的影响

    Institute of Scientific and Technical Information of China (English)

    黄居科; 麦荣康; 陈尚杰

    2009-01-01

    Objective To observe the effect of low-frequency repetitive transcranial magnetic stimulation in improving the memory function and quality of life of patients with traumatic brain injury. Methods Sixty patients with brain injury were randomly divided into the treatmem group and control group. The patients in the control group received conventional treatments (including medications, acupuncture and exercise training), and those in the treatment group were given additional low-frequency repetitive transcranial magnetic stimulation treatment. Scores of the Rivermead Behavioral Memory Test (RBMT) and Functional independence Measure (FIM) were recorded before and after the treatments and compared between the two groups. Results The patients in both of the groups showed significant improvements in RBMT and FIM scores after the treatments (P<0.05). The improvements in RBMT and FIM scores after the treatments differed significantly between the two groups (P<0.05). Conclusion Low-frequency repetitive transcranial magnetic stimulation can significantly improve the cognitive function and functional independence of patients with traumatic brain injury.%目的 观察低频重复经颅磁刺激改善脑外伤患者的认知功能和功能独立的作用.方法 将60例脑损伤患者按随机数字表法分为治疗组和对照组(各30例),均给予常规治疗.治疗组在此基础上应用低频重复经颅磁刺激治疗,连续治疗5 d为1个疗程,疗程之间间隔2d,连续4个疗程.观察两组患者治疗前后Rivermead行为记忆评分(RBMT)和功能独立性评分(FIM).结果 两组患者治疗后RBMT评分(治疗组:17.72±5.69,对照组:16.86±4.82)和FIM评分(治疗组:75.19±16.55,对照组:59.86±15.27)均较治疗前(治疗组:13.97±4.37,对照组:14.25±4.51;治疗组:43.21±12.62,对照组:45.79±13.97)有明显改善,比较差异有统计学意义(P<0.05);两组治疗前后RBMT评分差值(3.68±2.06 vs 2.71±1.17)和FIM评分差值(31.86±10.89 vs 18.71

  19. Radiological assessment of the PRF/BMSC efficacy in the treatment of aseptic nonunions: A retrospective study on 90 subjects.

    Science.gov (United States)

    Dallari, D; Rani, N; Sabbioni, G; Mazzotta, A; Cenacchi, A; Savarino, L

    2016-11-01

    Nonunion is a major orthopaedic concern because of treatment difficulty, high costs and devastating effects on the patients' life quality. Therefore, there is interest in the use of bone substitutes and cell-based strategies to augment fracture repair. We aimed to verify if Platelet Rich Fibrin (PRF) added with bone marrow stromal cells (BMSC) was able to improve the reparative process in the aseptic nonunion, and to establish whether it was worthwhile with atrophic nonunion. The primary outcome was radiological union. As secondary endpoint, the healing time was assessed, and the radiological consolidation grade at each follow-up. We identified 113 subjects with tibia or femur nonunion and retrospectively created two groups. Group A was constituted by 56 subjects who underwent the standard procedure, i.e. Judet decortication with/out internal fixation devices, and opposite cortical homoplastic stick. In 57 patients, the standard procedure was modified by adding PRF and BMSC carried by homologous lyophilised bone chips (group B). The same surgeon performed all the operations. To our knowledge, no data are reported in the literature about such application. Since a "gold standard" for healing quantification does not exist, a new scoring radiological system was applied, at 1.5, 3, 6, 12 and 24 months after treatment. At the final 24-month follow-up, the radiological union percentage was 94,12 in group B and 95,12% in group A. A decreased healing time was demonstrated in the presence of PRF/BMSC in comparison with the standard procedure. When we compared the radiological scores at each follow-up, we found that the PRF/BMSC combination significantly improved the consolidation grade at 1.5-, 3- and 6-month follow-up in femurs and at 1.5-month follow-up in tibiae. Furthermore, an improved consolidation grade was demonstrated in the atrophic subjects treated with adjuvants compared to atrophic patients treated with the standard procedure at 1.5-month follow-up. This study

  20. The coronally advanced flap in combination with platelet-rich fibrin (PRF) and enamel matrix derivative in the treatment of gingival recession: a comparative study.

    Science.gov (United States)

    Jankovic, Sasha; Aleksic, Zoran; Milinkovic, Iva; Dimitrijevic, Bozidar

    2010-01-01

    The main objective of this study was to evaluate the clinical effectiveness of platelet-rich fibrin membrane used in combination with a coronally advanced flap (CAF) and to compare it with the use of an enamel matrix derivative (EMD) in combination with a coronally advanced flap in gingival recession treatment. 20 split-mouth cases of maxillary anterior teeth or bicuspids presenting with Miller Class I or II gingival recession were treated with a CAF combined with a platelet-rich fibrin membrane (PRF group) or with EMD (EMD group) placed under a CAF. The following parameters were measured at baseline and at 12 months post treatment: gingival recession (GR), apicocoronal width of the keratinized tissue (WKT), and probing depth (PD). Complete rot coverage in the PRF group was 65% (13 out of 20 recessions) and 60% in the EMD group (12 out of 20 recessions). GR was 4.10 ± 1.05 mm in the PRF group and 3.90 ± 1.00 mm in the EMD group at baseline, and 1.05 ± 0.45 mm in the PRF group and 1.15 ± 0.65 mm in the EMD group at 12 months. The difference observed between the tow groups at 12 months was statistically significant. Average root coverage was 70.5% in the EMD group and 72.1% in the PRF group. WKT was 1.30 ± 0.56 mm in the EMD group and 1.45 ± 0.86 mm in the PRF group at baseline, and 1.90 ± 0.81 mm in the EMD group and 1.62 ± 0.28 mm in the PRF group at 12 months. The difference observed between the two groups at 12 months was not statistically significant. Twelve-month changes in PD were not significantly different between the two groups. The pain intensity was statistically different between the two groups. The pain intensity was statistically different between groups for the first 5 days, favoring the PRF group. The present study did not succeed in demonstrating any clinical advantage of the use of PRF compared to EMD in the coverage of gingival recession with the CAF procedure. The EMD group showed a higher success rate in increasing WKT than did the PRF

  1. DC high voltage to drive helium plasma jet comprised of repetitive streamer breakdowns

    CERN Document Server

    Wang, Xingxing

    2016-01-01

    This paper demonstrates and studies helium atmospheric pressure plasma jet comprised of series of repetitive streamer breakdowns, which is driven by a pure DC high voltage (auto-oscillations). Repetition frequency of the breakdowns is governed by the geometry of discharge electrodes/surroundings and gas flow rate. Each next streamer is initiated when the electric field on the anode tip recovers after the previous breakdown and reaches the breakdown threshold value of about 2.5 kV/cm. Repetition frequency of the streamer breakdowns excited using this principle can be simply tuned by reconfiguring the discharge electrode geometry. This custom-designed type of the helium plasma jet, which operates on the DC high voltage and is comprised of the series of the repetitive streamer breakdowns at frequency about 13 kHz, is demonstrated.

  2. Growth factor and pro-inflammatory cytokine contents in platelet-rich plasma (PRP), plasma rich in growth factors (PRGF), advanced platelet-rich fibrin (A-PRF), and concentrated growth factors (CGF).

    Science.gov (United States)

    Masuki, Hideo; Okudera, Toshimitsu; Watanebe, Taisuke; Suzuki, Masashi; Nishiyama, Kazuhiko; Okudera, Hajime; Nakata, Koh; Uematsu, Kohya; Su, Chen-Yao; Kawase, Tomoyuki

    2016-12-01

    The development of platelet-rich fibrin (PRF) drastically simplified the preparation procedure of platelet-concentrated biomaterials, such as platelet-rich plasma (PRP), and facilitated their clinical application. PRF's clinical effectiveness has often been demonstrated in pre-clinical and clinical studies; however, it is still controversial whether growth factors are significantly concentrated in PRF preparations to facilitate wound healing and tissue regeneration. To address this matter, we performed a comparative study of growth factor contents in PRP and its derivatives, such as advanced PRF (A-PRF) and concentrated growth factors (CGF). PRP and its derivatives were prepared from the same peripheral blood samples collected from healthy donors. A-PRF and CGF preparations were homogenized and centrifuged to produce extracts. Platelet and white blood cell counts in A-PRF and CGF preparations were determined by subtracting those counts in red blood cell fractions, supernatant acellular serum fractions, and A-PRF/CGF exudate fractions from those counts of whole blood samples. Concentrations of growth factors (TGF-β1, PDGF-BB, VEGF) and pro-inflammatory cytokines (IL-1β, IL-6) were determined using ELISA kits. Compared to PRP preparations, both A-PRF and CGF extracts contained compatible or higher levels of platelets and platelet-derived growth factors. In a cell proliferation assay, both A-PRF and CGF extracts significantly stimulated the proliferation of human periosteal cells without significant reduction at higher doses. These data clearly demonstrate that both A-PRF and CGF preparations contain significant amounts of growth factors capable of stimulating periosteal cell proliferation, suggesting that A-PRF and CGF preparations function not only as a scaffolding material but also as a reservoir to deliver certain growth factors at the site of application.

  3. Improved Discrimination of Visual Stimuli Following Repetitive Transcranial Magnetic Stimulation

    OpenAIRE

    Waterston, Michael L.; Pack, Christopher C.

    2010-01-01

    BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary t...

  4. Effect of low frequency repetitive transcranial magnetic stimulation on dysfunction and depressive symptoms of parkinson disease patients%低频重复经颅磁刺激对帕金森病患者功能障碍及抑郁症状的影响

    Institute of Scientific and Technical Information of China (English)

    唐雪琴; 邓景贵; 宋涛; 刘佳; 张长杰; 吴亚岑; 桂一莎

    2015-01-01

    Objective To discuss the clinical effect of transcranial magnetic stimulation in treatment of dysfunction and depression of parkinson disease patients. Methods A totao of 50 cases of parkinson patients were randomly divided into the observation group and the control group, each group 25 cases, the control group was given conventional medicine and rehabilitation training, the observation group was given low frequency repetitive transcranial magnetic stimulation based on the control group. Results After 1 months of treatment, UPDRS Ⅰ, UPDRS II, UPDRS III, UP-DRS total scores in the observation group were lower than that in the control group, there was statistical significance (P0.05), but HAMD score in the observation group was lower than that in the control group, there was statis-tical significance (P0.05),但观察组的HAMD评分低于对照组,差异有统计学意义(P<0.05)。结论低频重复经颅磁刺激可作为一项无创性物理治疗帕金森病的措施。

  5. Circuit considerations for repetitive railguns

    Energy Technology Data Exchange (ETDEWEB)

    Honih, E.M.

    1986-01-01

    Railgun electromagnetic launchers have significant military and scientific potential. They provide direct conversion of electrical energy to projectile kinetic energy, and they offer the hope of achieving projectile velocities greatly exceeding the limits of conventional guns. With over 10 km/sec already demonstrated, railguns are attracting attention for tactical and strategic weapons systems and for scientific equation-of-state research. The full utilization of railguns will require significant improvements in every aspect of system design - projectile, barrel, and power source - to achieve operation on a large scale. This paper will review fundamental aspects of railguns, with emphasis on circuit considerations and repetitive operation.

  6. Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects

    KAUST Repository

    Luong, Minh Bau

    2016-10-10

    Chemical aspects of the ignition of a primary reference fuel (PRF)/air mixture under reactivity controlled compression ignition (RCCI) and stratified charge compression ignition (SCCI) conditions are investigated by analyzing two-dimensional direct numerical simulation (DNS) data with chemical explosive mode (CEM) analysis. CEMA is adopted to provide fundamental insights into the ignition process by identifying controlling species and elementary reactions at different locations and times. It is found that at the first ignition delay, low-temperature chemistry (LTC) represented by the isomerization of alkylperoxy radical, chain branching reactions of keto-hydroperoxide, and H-atom abstraction of n-heptane is predominant for both RCCI and SCCI combustion. In addition, explosion index and participation index analyses together with conditional means on temperature verify that low-temperature heat release (LTHR) from local mixtures with relatively-high n-heptane concentration occurs more intensively in RCCI combustion than in SCCI combustion, which ultimately advances the overall RCCI combustion and distributes its heat release rate over time. It is also found that at the onset of the main combustion, high-temperature heat release (HTHR) occurs primarily in thin deflagrations where temperature, CO, and OH are found to be the most important species for the combustion. The conversion reaction of CO to CO and hydrogen chemistry are identified as important reactions for HTHR. The overall RCCI/SCCI combustion can be understood by mapping the variation of 2-D RCCI/SCCI combustion in temperature space onto the temporal evolution of 0-D ignition.

  7. Repetitive motor behavior: further characterization of development and temporal dynamics.

    Science.gov (United States)

    Muehlmann, Amber M; Bliznyuk, Nikolay; Duerr, Isaac; Lewis, Mark H

    2015-03-01

    Repetitive behaviors are diagnostic for autism spectrum disorders, common in related neurodevelopmental disorders, and normative in typical development. In order to identify factors that mediate repetitive behavior development, it is necessary to characterize the expression of these behaviors from an early age. Extending previous findings, we characterized further the ontogeny of stereotyped motor behavior both in terms of frequency and temporal organization in deer mice. A three group trajectory model provided a good fit to the frequencies of stereotyped behavior across eight developmental time points. Group based trajectory analysis using a measure of temporal organization of stereotyped behavior also resulted in a three group solution. Additionally, as the frequency of stereotyped behavior increased with age, the temporal distribution of stereotyped responses became increasingly regular or organized indicating a strong association between these measures. Classification tree and principal components analysis showed that accurate classification of trajectory group could be done with fewer observations. This ability to identify trajectory group membership earlier in development allows for examination of a wide range of variables, both experiential and biological, to determine their impact on altering the expected trajectory of repetitive behavior across development. Such studies would have important implications for treatment efforts in neurodevelopmental disorders such as autism.

  8. 人肝癌PLC/PRF-5细胞中干细胞样细胞的分离及其特异性miRNAs的筛选%Isolation of stem-like cells from human hepatocellular carcinoma PLC/PRF-5 cells and screening for their specific miRNAs

    Institute of Scientific and Technical Information of China (English)

    郑秋红; 许扬梅; 魏植强; 龚福生; 杨建伟; 谢云青; 应敏刚

    2011-01-01

    Objective: To isolate stem-like cells from hepatocellular carcinoma cell line PLC/PRF-5 and to study their miRNA profile. Methods:ABCG2 + and ABCG2- PLC/PRF-5 cells were isolated from the PLC/PRF-5 cell line by magnetic activated cell sorting (MACS) method, and further identified by flow cytometry. The colony formation ability in soft agar and tumor formation ability in NOD/SCID mice of ABCG2+ and ABCG2- PLC/PRF-5 cells were observed. miRNA chip was adopted to screen the differentially expressed miRNAs between ABCG2 + and ABCG2 - PLC/PRF-5 cells; and real-time PCR assay was used to confirm the results of miRNA chip. Results:The purity of ABCG2 + PLC/PRF-5 cells isolated by MACS method was ( 84.20 ± 4.52 ) %. The colony number and size formed by ABCG2 + PLC/PRF-5 cells were more and larger than those formed by ABCG2 - cells (47.17 ± 10.50 vs 23.33 ±7.31, P <0.05). 1 × 104 ABCG2 + cells could form tumors with at least 5 × 105 cells needed for ABCG2 - cells. The size of tumors generated by 5 × 105 ABCG2 + cells was larger than that by the ABCG2 - cells ( [ 3.73 ± 1.19 ]cm3 vs [0.72 ± 0.57 ] cm3, P < O. Ol ). There are 20 miRNAs differentially expressed between ABCG2 + and ABCG2- cells, with 13 up-regulated and 7 down-regulated. Realtime PCR assay was applied to further verify the differential expression of hsa-miR-30a and hsa-miR-630, and the results were in accordance with those of miRNA chip. Conclusion: ABCG2+ PLC/PRF-5 cells in hepatocellular carcinoma cell line PLC/PRF-5 have the properties of cancer stem cells. Twenty miRNAs are differentially expressed between ABCG2 + and ABCG2 - PLC/PRF-5 cells, which might play important roles in the carcinogenesis of hepatocellular carcinoma.%目的:分选及鉴定人肝癌PLC/PRF-5细胞中的肝癌干细胞样细胞,研究其microRNAs(miRNAs)表达谱.方法:以ABCG2为表面标志,免疫磁珠法分选、流式细胞术检测ABCG2+和ABCG2-PLC/PRF-5细胞,观察ABCG2+与ABCG2-PLC/PRF-5细胞的琼脂克隆

  9. Repetitive transcranial magnetic stimulation and drug addiction.

    Science.gov (United States)

    Barr, Mera S; Farzan, Faranak; Wing, Victoria C; George, Tony P; Fitzgerald, Paul B; Daskalakis, Zafiris J

    2011-10-01

    Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that is now being tested for its ability to treat addiction. This review discusses current research approaches and results of studies which measured the therapeutic use of rTMS to treat tobacco, alcohol and illicit drug addiction. The research in this area is limited and therefore all studies evaluating the therapeutic use of rTMS in tobacco, alcohol or illicit drug addiction were retained including case studies through NCBI PubMed ( http://www.ncbi.nlm.nih.gov ) and manual searches. A total of eight studies were identified that examined the ability of rTMS to treat tobacco, alcohol and cocaine addiction. The results of this review indicate that rTMS is effective in reducing the level of cravings for smoking, alcohol, and cocaine when applied at high frequencies to the dorsolateral prefrontal cortex (DLPFC). Furthermore, these studies suggest that repeated sessions of high frequency rTMS over the DLPFC may be most effective in reducing the level of smoking and alcohol consumption. Although work in this area is limited, this review indicates that rTMS is a promising modality for treating drug addiction.

  10. The discharge mode transition and O(5p1) production mechanism of pulsed radio frequency capacitively coupled plasma

    Science.gov (United States)

    Liu, X. Y.; Hu, J. T.; Liu, J. H.; Xiong, Z. L.; Liu, D. W.; Lu, X. P.; Shi, J. J.

    2012-07-01

    The discharge mode transition from uniform plasma across the gas gap to the α mode happens at the rising phase of the pulsed radio frequency capacitively coupled plasma (PRF CCP). This transition is attributed to the fast increasing stochastic heating at the edge of sheath. In the second stage with the stable current and voltage amplitude, the consistency between experimental and numerical spatial-temporal 777 nm emission profile suggests that He* and He2* dominate the production of O(5p1) through dissociation and excitation of O2. Finally, the sterilization efficiency of PRF CCP is found to be higher than that of plasma jet.

  11. Domestication-driven Gossypium profilin 1 (GhPRF1) gene transduces early flowering phenotype in tobacco by spatial alteration of apical/floral-meristem related gene expression.

    Science.gov (United States)

    Pandey, Dhananjay K; Chaudhary, Bhupendra

    2016-05-13

    Plant profilin genes encode core cell-wall structural proteins and are evidenced for their up-regulation under cotton domestication. Notwithstanding striking discoveries in the genetics of cell-wall organization in plants, little is explicit about the manner in which profilin-mediated molecular interplay and corresponding networks are altered, especially during cellular signalling of apical meristem determinacy and flower development. Here we show that the ectopic expression of GhPRF1 gene in tobacco resulted in the hyperactivation of apical meristem and early flowering phenotype with increased flower number in comparison to the control plants. Spatial expression alteration in CLV1, a key meristem-determinacy gene, is induced by the GhPRF1 overexpression in a WUS-dependent manner and mediates cell signalling to promote flowering. But no such expression alterations are recorded in the GhPRF1-RNAi lines. The GhPRF1 transduces key positive flowering regulator AP1 gene via coordinated expression of FT4, SOC1, FLC1 and FT1 genes involved in the apical-to-floral meristem signalling cascade which is consistent with our in silico profilin interaction data. Remarkably, these positive and negative flowering regulators are spatially controlled by the Actin-Related Protein (ARP) genes, specifically ARP4 and ARP6 in proximate association with profilins. This study provides a novel and systematic link between GhPRF1 gene expression and the flower primordium initiation via up-regulation of the ARP genes, and an insight into the functional characterization of GhPRF1 gene acting upstream to the flowering mechanism. Also, the transgenic plants expressing GhPRF1 gene show an increase in the plant height, internode length, leaf size and plant vigor. Overexpression of GhPRF1 gene induced early and increased flowering in tobacco with enhanced plant vigor. During apical meristem determinacy and flower development, the GhPRF1 gene directly influences key flowering regulators through ARP

  12. Leucocyte- and platelet-rich fibrin (L-PRF) as a regenerative medicine strategy for the treatment of refractory leg ulcers: a prospective cohort study.

    Science.gov (United States)

    Pinto, Nelson R; Ubilla, Matias; Zamora, Yelka; Del Rio, Verónica; Dohan Ehrenfest, David M; Quirynen, Marc

    2017-07-20

    Chronic wounds (VLU: venous leg ulcer, DFU: diabetic foot ulcer, PU: pressure ulcer, or complex wounds) affect a significant proportion of the population. Despite appropriate standard wound care, such ulcers unfortunately may remain open for months or even years. The use of leukocyte- and platelet-rich fibrin (L-PRF) to cure skin ulcers is a simple and inexpensive method, widely used in some countries but unknown or neglected in most others. This auto-controlled prospective cohort study explored and quantified accurately for the first time the adjunctive benefits of topical applications of L-PRF in the management of such refractory ulcers in a diverse group of patients. Forty-four consecutive patients with VLUs (n = 28, 32 wounds: 17 ≤ 10 cm(2) and 15 > 10 cm(2)), DPUs (n = 9, 10 wounds), PUs (n = 5), or complex wounds (n = 2), all refractory to standard treatment for ≥3 months, received a weekly application of L-PRF membranes. L-PRF was prepared following the original L-PRF method developed more than 15 years ago (400g, 12 minutes) using the Intra-Spin L-PRF centrifuge/system and the XPression box kit (Intra-Lock, Boca Raton, FL, USA; the only CE/FDA cleared system for the preparation of L-PRF). Changes in wound area were recorded longitudinally via digital planimetry. Adverse events and pain levels were also registered. All wounds showed significant improvements after the L-PRF therapy. All VLUs ≤ 10 cm(2), all DFUs, as well as the two complex wounds showed full closure within a 3-month period. All wounds of patients with VLUs > 10 cm(2) who continued therapy (10 wounds) could be closed, whereas in the five patients who discontinued therapy improvement of wound size was observed. Two out of the five PUs were closed, with improvement in the remaining three patients who again interrupted therapy (surface evolution from 7.35 ± 4.31 cm(2) to 5.78 ± 3.81 cm(2)). No adverse events were observed. A topical application of L-PRF on

  13. Relevance of Choukroun's Platelet-Rich Fibrin (PRF) and SMAS flap in primary reconstruction after superficial or subtotal parotidectomy in patients with focal pleiomorphic adenoma: a new technique.

    Science.gov (United States)

    Charrier, J B; Monteil, J P; Albert, S; Collon, S; Bobin, S; Dohan Ehrenfest, D M

    2008-01-01

    Parotidectomy leaves a retromandibular hollow area in proportion with the amount of gland resected. Many surgeons perform primary reconstruction after superficial or subtotal parotidectomy in patients with exo-facial pleiomorphic focal adenoma. Many techniques have been proposed. We present a new technique of filling of the parotidectomy chamber by a second generation leucocyte and platelet concentrate, Platelet-Rich Fibrin (PRF, Choukroun's method). 10 patients were included in this preliminary study. Subtotal parotidectomy was performed through classic procedure or lifting procedure. The macroscopic security margin of resection usually allowed performance of a SMAS flap. PRF was prepared following the original Choukroun's method. PRF slow resorption after filling of the exeresis cavity, offers a key aesthetic interest. The fibrin matrix of this biomaterial has many angiogenic and healing properties. Synergetic action of the fibrin and the platelets cytokines within PRF may improve revascularization and postoperative resumption of facial nerve function. The membrane formed by the fibrin dense fibrillary network, as well as the SMAS flap, may help to prevent the Frey's syndrome. We propose the use of PRF as a filling, healing and interposition material after parotidectomy for benign parotid tumors. Preliminary results are very encouraging. Longer prospective evaluation of this technique is necessary.

  14. The impact of the centrifuge characteristics and centrifugation protocols on the cells, growth factors, and fibrin architecture of a leukocyte- and platelet-rich fibrin (L-PRF) clot and membrane.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Pinto, Nelson R; Pereda, Andrea; Jiménez, Paula; Corso, Marco Del; Kang, Byung-Soo; Nally, Mauricio; Lanata, Nicole; Wang, Hom-Lay; Quirynen, Marc

    2017-04-24

    L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge. In the first part, four different commercially available centrifuges were used to produce L-PRF, following the original L-PRF production method (glass-coated plastic tubes, 400 g force, 12 minutes). The tested systems were the original L-PRF centrifuge (Intra-Spin, Intra-Lock, the only CE and FDA cleared system for the preparation of L-PRF) and three other laboratory centrifuges (not CE/FDA cleared for L-PRF): A-PRF 12 (Advanced PRF, Process), LW-UPD8 (LW Scientific) and Salvin 1310 (Salvin Dental). Each centrifuge was opened for inspection, two accelerometers were installed (one radial, one vertical), and data were collected with a spectrum analyzer in two configurations (full-load or half load). All clots and membranes were collected into a sterile surgical box (Xpression kit, Intra-Lock). The exact macroscopic (weights, sizes) and microscopic (photonic and scanning electron microscopy SEM) characteristics of the L-PRF produced with these four different machines were evaluated. In the second part, venous blood was taken in two groups, respectively, Intra-Spin 9 ml glass-coated plastic tubes (Intra-Lock) and A-PRF 10 ml glass tubes (Process). Tubes were immediately centrifuged at 2700 rpm (around 400 g) during 12 minutes to produce L-PRF or at 1500 rpm during 14 minutes to produce A-PRF

  15. Platelet-rich fibrin (PRF) in implant dentistry in combination with new bone regenerative technique in elderly patients.

    Science.gov (United States)

    Cortese, Antonio; Pantaleo, Giuseppe; Borri, Antonio; Caggiano, Mario; Amato, Massimo

    2016-01-01

    Some studies have demonstrated that platelet rich fibrin (PRF) is a healing biomaterial with a great potential for bone and soft tissue regeneration, without any inflammatory reactions and may be used alone or in combination with bone grafts, promoting hemostasis, bone growth, and maturation. PRF appears as a natural and satisfactory aid in bone regenerative surgery in elderly patients with favorable results and low risks. This study wants to demonstrate how PRF in association with a new split crest augmentation technique can be a great aid in implant rehabilitation, especially in the elderly patients, when bone regeneration is required. Ten patients were treated in this study, five following the flapless split crest new procedure and other five patients following traditional procedure without split crest as control. Five patients with an average age between 50 and 60 years were selected to be operated with a split crest flapless modified technique in order to optimize the regenerative conditions with a bone augmentation and implant insertion in one single stage procedure. For all the patients autologous PRF has been used to fill the split crest gap or simply as regenerative material. Orthopantomography, intraoral radiography and CT DentaScan/CT Cone beam were performed for every patient before the treatment and at follow-up time exeption made for CT. All cases were successful, there were no problems at surgery time, at post-operative and at osteointegration periods. All implants achieved osteointegration. These results were obtained by accurately managing immediate and late post operative period in all of the operated cases. Mean difference for height bone loss between the two groups of patients was 2.4mm at T1 and 2.2mm at T3. The rationale of this split crest flapless modified technique is to obtain a proper buccal cortex expansion preserving its vascular supply avoiding periosteal elevation for better cortical bone nourishing. Moreover, advantages are reported

  16. Practicing novel, praxis-like movements: physiological effects of repetition

    Directory of Open Access Journals (Sweden)

    Joshua Benjamin Ewen

    2016-02-01

    Full Text Available Our primary goal was to develop and validate a task that could provide evidence about how humans learn praxis gestures, such as those involving the use of tools. To that end, we created a video-based task in which subjects view a model performing novel, meaningless one-handed actions with kinematics similar to praxis gestures. Subjects then imitated the movements with their right hand. Trials were repeated 6 times to examine practice effects. EEG was recorded during the task. As a control, subjects watched videos of a model performing a well-established (over learned tool-use gesture. These gestures were also imitated 6 times. Demonstrating convergent validity, EEG measures of task-related cortical activation were similar in topography and frequency between the novel gesture task and the overlearned, praxis gesture task. As in studies assessing motor skill learning with simpler tasks, cortical activation during novel gesture learning decreased as the same gestures were repeated. In the control condition, repetition of overlearned tool-use gestures were also associated with reductions in activation, though to a lesser degree. Given that even overlearned, praxis gestures show constriction of EEG activity with repetition, it is possible that that attentional effects drive some of the repetition effects seen in EEG measures of activation during novel gesture repetition.

  17. A repetitive 0.14 THz relativistic surface wave oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guangqiang; Tong Changjiang; Li Xiaoze; Wang Xuefeng; Li Shuang; Lu Xicheng [Northwest Institute of Nuclear Technology, P.O. Box 69-1, Xi' an 710024 (China); Wang Jianguo [Northwest Institute of Nuclear Technology, P.O. Box 69-1, Xi' an 710024 (China); School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2013-04-15

    Preliminary experimental results of a repetitive 0.14 THz overmoded relativistic surface wave oscillator (RSWO) are presented in this paper. The repetitive RSWO is developed by using a rectangularly corrugated slow-wave structure with overmoded ratio of 3 and a foilless diode emitting annular electron beam with thickness of 0.5 mm. The high quality electron beams at the repetition rate of 10 are obtained over a wide range of diode voltage (180 kV < U < 240 kV) and current (700 A < I < 1.2 kA). The generation experiments of RSWO are conducted at an axial pulsed magnetic field whose maximum strength and duration can reach about 2.7 T and 1 s, respectively. The experimental results show that the RSWO successfully produces reasonable uniform terahertz pulses at repetition rate of 10, and the pulse duration, frequency, and power of a single pulse are about 1.5 ns, 0.154 THz, and 2.6 MW, respectively, whereas the dominated radiation mode of the RSWO is TM{sub 02}.

  18. REPETITIVE MANUAL OPERATIONS IN THE DAIRY SECTOR: ANALYSES AND CRITERIA FOR INTERVENTION

    Directory of Open Access Journals (Sweden)

    Pier Riccardo Porceddu

    2008-03-01

    Full Text Available For the health of workers it is necessary to consider, together with traditional risks (noise, vibrations, microclimate etc., risks deriving from repetitive movements, which can generate muscolo-skeletal disorders. These risks can be found in artisan dairies, where the limited use of machinery and the rapid successive passages for processing the milk require high-frequency repetitive manual movements. The study analysed the risks of repetitive movements for workers in a dairy, using the OCRA method. Various risk-involving operations emerged, which require the re-planning of the workplace. The proposed interventions have not involved high costs for the dairy, or a loss of productivity.

  19. [Repetition and fear of dying].

    Science.gov (United States)

    Lerner, B D

    1995-03-01

    In this paper a revision is made of the qualifications of Repetition (R) in Freuds work, i.e. its being at the service of the Pleasure Principle and, beyond it, the binding of free energy due to trauma. Freud intends to explain with this last concept the "fort-da" and the traumatic dreams (obsessively reiterated self-reproaches may be added to them). The main thesis of this work is that R. is not only a defense against the recollection of the ominous past (as in the metaphorical deaths of abandonment and desertion) but also a way of maintaining life and identify fighting against the inescapable omninous future (known but yet experienced), i.e. our own death. Some forms of R. like habits, identificatory behaviors and sometimes even magic, are geared to serve the life instinct. A literary illustration shows this desperate fight.

  20. Pressure rig for repetitive casting

    Science.gov (United States)

    Vasquez, Peter (Inventor); Hutto, William R. (Inventor); Philips, Albert R. (Inventor)

    1989-01-01

    The invention is a pressure rig for repetitive casting of metal. The pressure rig performs like a piston for feeding molten metal into a mold. Pressure is applied to an expandable rubber diaphragm which expands like a balloon to force the metal into the mold. A ceramic cavity which holds molten metal is lined with blanket-type insulating material, necessitating only a relining for subsequent use and eliminating the lengthy cavity preparation inherent in previous rigs. In addition, the expandable rubber diaphragm is protected by the insulating material thereby decreasing its vulnerability to heat damage. As a result of the improved design the life expectancy of the pressure rig contemplated by the present invention is more than doubled. Moreover, the improved heat protection has allowed the casting of brass and other alloys with higher melting temperatures than possible in the conventional pressure rigs.

  1. High-efficiency synthesis of nanoparticles in a repetitive multigap spark discharge generator

    Science.gov (United States)

    Ivanov, V. V.; Efimov, A. A.; Mylnikov, D. A.; Lizunova, A. A.; Bagazeev, A. V.; Beketov, I. V.; Shcherbinin, S. V.

    2016-08-01

    We describe a method of obtaining aerosol nanoparticles in a repetitive spark discharge generator with 12 interelectrode gaps between tin electrodes, which operates at a pulse repetition frequency of 2.5 kHz. During synthesis of tin oxide nanoparticles in air, the mass productivity of the gas discharge generator reaches up to 9 g/h for primary particles with characteristic sizes within 5-10 nm and agglomerate size on the order of 50 nm.

  2. The effect of L-PRF membranes on bone healing in rabbit tibiae bone defects: micro-CT and biomarker results.

    Science.gov (United States)

    Faot, Fernanda; Deprez, Sanne; Vandamme, Katleen; Camargos, Germana V; Pinto, Nelson; Wouters, Jasper; van den Oord, Joost; Quirynen, Marc; Duyck, Joke

    2017-04-12

    More insight into the biological fundamentals of leukocyte platelet-rich fibrin (L-PRF) guided healing is necessary to recommend its application, in particular in deficient bone sites that need to support implants. This study investigated the short-term bone healing effect of L-PRF treatment in cylindrical non-critical sized bone defects with 3 mm diameter and 6 mm depth in tibiae of 18 adult male New Zealand White rabbits. After a randomization process, 96 bone defects were prepared and half of them were filled with a L-PRF membrane, while untreated defects in the opposite tibia served as control group. The rabbits were euthanized after 7, 14 or 28 days of healing. The bone healing of the cortical and medullary areas was investigated by micro-CT, while the expression of molecular markers (RUNX2, VEGFA, COL1A2 and BMP2) was assessed by qRT-PCR. Treatment with L-PRF did not affect the micro-structural bone characteristics of the repaired bone tissue, except for a decrease in the trabecular connectivity at the cortical level after 14 days of healing. At this time, RUNX2 and VEGFA mRNA levels were significantly lower in the treated defects. L-PRF membranes thus had a temporary negative influence on the bone microarchitecture (Tb.Pf) and on the RUNX2 and VEGFA expression during early bone healing. Overall, L-PRF treatment did not enhance bone regeneration in these non-critical size defects after 28 days.

  3. In-vitro release pharmacokinetics of amikacin, teicoplanin and polyhexanide in a platelet rich fibrin-layer (PRF)-a laboratory evaluation of a modern, autologous wound treatment.

    Science.gov (United States)

    Knafl, Daniela; Thalhammer, Florian; Vossen, Matthias G

    2017-01-01

    Platelet rich fibrin (PRF) is an autologous fibrin glue, produced from patients' blood, which, besides intraoperative use, has applications in the treatment of infected wounds. The combination with antimicrobial agents results in a prolonged antibacterial effect allowing for wound dressing change intervals of seven days even in infected wounds. The aim of this study was to evaluate release kinetics of amikacin, teicoplanin or polyhexanide from a PRF-layer. PRF mixed with teicoplanin, amikacin or polyhexanide was sprayed on a silicon gauze patch and put on a colombia agar with bacteria with known minimal inhibitory concentration (MIC) and incubated for 24 hours and afterwards transferred to another agar with the same bacterial strain. Inhibition zones were measured every 24 hours. This was repeated on 7 consecutive days. Antibiotic concentrations were calculated by interpolation. More than 1000 mg/L teicoplanin were released within the first 24 hours and 28.22 mg/L after 168 hours. Amikacin release was above 10,000 mg/L within the first 24 hours and still 120.8 mg/L after 120 hours. A release of polyhexanide could be verified for the first 24 hours only. Consequently teicoplanin and amikacin released from PRF showed antimicrobial in-vitro effects for almost a week, whereas an antimicrobial effect of polyhexanide could only be verified for the first 24 hours. Our Results show that a weekly dressing regimen may be justified in wounds treated with PRF plus amikacin or teicoplanin, since bacteria will be eradicated over a considerable period of time after a single application of PRF.

  4. A naturally occurring prfA truncation in a Listeria monocytogenes field strain contributes to reduced replication and cell-to-cell spread.

    Science.gov (United States)

    Rupp, Sebastian; Aguilar-Bultet, Lisandra; Jagannathan, Vidhya; Guldimann, Claudia; Drögemüller, Cord; Pfarrer, Christiane; Vidondo, Beatriz; Seuberlich, Torsten; Frey, Joachim; Oevermann, Anna

    2015-08-31

    Listeria (L.) monocytogenes is an environmental bacterium that may become an intracellular pathogen upon ingestion to cause gastroenteritis, septicaemia, abortions, and/or fatal infections of the central nervous system. We here describe a L. monocytogenes field strain (JF5171) isolated from a bovine placenta in the context of abortion, which exhibited attenuation in bovine brain-slice cultures. The whole genome of strain JF5171 was sequenced, and the invasion, replication, and intercellular spread of JF5171 were further analyzed by quantification of colony forming units and immunofluorescence studies. Phospholipase and hemolysis activity of JF5171 were also quantified along with transcription levels of actA, hly and prfA. The data obtained were compared to those of the widely used L. monocytogenes reference strain, EGD-e. JF5171 exhibited reduced replication and lower levels of phospholipase and hemolysis activity. Invasion and cell-to-cell spread was strongly decreased compared to EGD-e, and actin polymerization was absent. A frame shift deletion was identified in the JF5171 coding region of the major regulator for virulence, prfA. This resulted in a truncated C-terminus sequence (WEN* vs. WGKLN*). In addition, a point mutation resulted in a lysine to arginine substitution at amino acid position 197. Complementation with prfA from EGD-e and with (EGD-e) prfA-K197N increased the replication and spread efficiency of JF5171. In contrast, complementation with the truncated version of prfA had no effect. Taken together, these results suggest that the truncated C-terminus of prfA considerably contributes to the strongly attenuated phenotype observed in vitro. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. 转录调控蛋白PrfA对两组新近发现的单核细胞增生李斯特菌基因的体外转录作用的研究%In vitro Transcription of Two Groups of Newly Identified and Putatively in vivo PrfA-Regulated Genes of Listeria monocytogenes

    Institute of Scientific and Technical Information of China (English)

    罗勤; 周青春; 邓灵福; 高强; 刘德立; GOEBEL Werner

    2006-01-01

    目的 研究转录调控蛋白PffA对两组新近发现的单核细胞增生李斯特菌基因的体外转录作用.方法 利用本室近年来建立的体外转录系统,对两组基于转录基因组体内研究发现的5个可能的受PffA不同调节的单核细胞增生李斯特菌基因进行了体外转录活性的研究.结果 第一组中的hpt基因的体外转录活性受PffA正调节,而其它4个基因既不被PffA正调节也不被负调节.结论 除hpt基因外,其它4个基因体外转录结果与体内实验不相一致,说明PrfA在体内可能通过复杂多样的非直接方式、或者还需要一些目前未知的因子来调控这些新近发现的基因的表达.%Objective The aim of study was to investigate PrfA-dependent transcription activities of two groups of newly identified and putatively in vivo PrfA-regulated genes of listeria monocytogenes. Methods Transcription initiation at promoters of five genes selected from the two groups based on the transcriptome analysis was studied by means of in vitro transcription system. Results The data showed that, among these new putative" PrfA-regulated" promoters, only the promoter of hpt gene belonging to group I was significantly activated by PrfA. In addition, this promoter was the only one exhibiting all essential features of a typical PrfA-dependent promoter. Neither positively nor negatively, was in vitro transcription starting at most of other promoters affected by PrfA. Conclusion These in vitro transcription results indicate that the effect of PrfA in vivo on the expression of these new genes might be committed in an indirect manner or via a complex process, and that the PrfA-mediated transcription of these genes, in contrast to the PrfA-dependent transcription of the known virulence genes ( including hpt), probably requires additional factors lacked in the in vitro transcription system.

  6. A feasible repetitive transcranial magnetic stimulation clinical protocol in migraine prevention

    Directory of Open Access Journals (Sweden)

    Shawn Zardouz

    2016-10-01

    Full Text Available Objective: This case series was conducted to determine the clinical feasibility of a repetitive transcranial magnetic stimulation protocol for the prevention of migraine (with and without aura. Methods: Five patients with migraines underwent five repetitive transcranial magnetic stimulation sessions separated in 1- to 2-week intervals for a period of 2 months at a single tertiary medical center. Repetitive transcranial magnetic stimulation was applied to the left motor cortex with 2000 pulses (20 trains with 1s inter-train interval delivered per session, at a frequency of 10 Hz and 80% resting motor threshold. Pre- and post-treatment numerical rating pain scales were collected, and percent reductions in intensity, frequency, and duration were generated. Results: An average decrease in 37.8%, 32.1%, and 31.2% were noted in the intensity, frequency, and duration of migraines post-repetitive transcranial magnetic stimulation, respectively. A mean decrease in 1.9±1.0 (numerical rating pain scale ± standard deviation; range: 0.4–2.8 in headache intensity scores was noted after the repetitive transcranial magnetic stimulation sessions. Conclusion: The tested repetitive transcranial magnetic stimulation protocol is a well-tolerated, safe, and effective method for migraine prevention.

  7. Repetition blindness for natural images of objects with viewpoint changes

    Directory of Open Access Journals (Sweden)

    Stephane eBuffat

    2013-01-01

    Full Text Available When stimuli are repeated in a rapid serial visual presentation (RSVP, observers sometimes fail to report the second occurrence of a target. This phenomenon is referred to as repetition blindness (RB. We report an RSVP experiment with photographs in which we manipulated object viewpoints between the first and second occurrences of a target (0-, 45-, or 90-degree changes, and spatial frequency content. Natural images were spatially filtered to produce low, medium, or high spatial-frequency stimuli. RB was observed for all filtering conditions. Surprisingly, for full-spectrum images, RB increased significantly as the viewpoint reached 90 degrees. For filtered images, a similar pattern of results was found for all conditions except for medium spatial-frequency stimuli. These findings suggest that object recognition in RSVP are subtended by viewpoint-specific representations for all spatial frequencies except medium ones.

  8. L-PRP/L-PRF in esthetic plastic surgery, regenerative medicine of the skin and chronic wounds.

    Science.gov (United States)

    Cieslik-Bielecka, Agata; Choukroun, Joseph; Odin, Guillaume; Dohan Ehrenfest, David M

    2012-06-01

    The use of platelet concentrates for topical use is of particular interest for the promotion of skin wound healing. Fibrin-based surgical adjuvants are indeed widely used in plastic surgery since many years in order to improve scar healing and wound closure. However, the addition of platelets and their associated growth factors opened a new range of possibilities, particularly for the treatment of chronic skin ulcers and other applications of regenerative medicine on the covering tissues. In the 4 families of platelet concentrates available, 2 families were particularly used and tested in this clinical field: L-PRP (Leukocyte- and Platelet-rich Plasma) and L-PRF (Leukocyte- and Platelet-Rich Fibrin). These 2 families have in common the presence of significant concentrations of leukocytes, and these cells are important in the local cleaning and immune regulation of the wound healing process. The main difference between them is the fibrin architecture, and this parameter considerably influences the healing potential and the therapeutical protocol associated to each platelet concentrate technology. In this article, we describe the historical evolutions of these techniques from the fibrin glues to the current L-PRP and L-PRF, and discuss the important functions of the platelet growth factors, the leukocyte content and the fibrin architecture in order to optimize the numerous potential applications of these products in regenerative medicine of the skin. Many outstanding perspectives are appearing in this field and require further research.

  9. The role of leukocytes from L-PRP/L-PRF in wound healing and immune defense: new perspectives.

    Science.gov (United States)

    Bielecki, Tomasz; Dohan Ehrenfest, David M; Everts, Peter A; Wiczkowski, Andrzej

    2012-06-01

    Platelet concentrates for topical use are innovative tools of regenerative medicine and their effects in various therapeutical situations are hotly debated. Unfortunately, this field of research mainly focused on the platelet growth factors, and the fibrin architecture and the leukocyte content of these products are too often neglected. In the four families of platelet concentrates, 2 families contain significant concentrations of leukocytes: L-PRP (Leukocyte- and Platelet-Rich Plasma) and L-PRF (Leukocyte- and Platelet-Rich Fibrin). The presence of leukocytes has a great impact on the biology of these products, not only because of their immune and antibacterial properties, but also because they are turntables of the wound healing process and the local factor regulation. In this article, the various kinds of leukocytes present in a platelet concentrate are described (particularly the various populations of granulocytes and lymphocytes), and we insist on the large diversity of factors and pathways that these cells can use to defend the wound site against infections and to regulate the healing process. Finally, the impact of these cells in the healing properties of the L-PRP and L-PRF is also discussed: if antimicrobial properties were already pointed out, effects in the regulation of cell proliferation and differentiation were also hypothesized. Leukocytes are key actors of many platelet concentrates, and a better understanding of their effects is an important issue for the development of these technologies.

  10. The nodC, nodG, and glgX genes of Rhizobium tropici strain PRF 81.

    Science.gov (United States)

    Oliveira, Luciana Ruano; Marcelino, Francismar Corrêa; Barcellos, Fernando Gomes; Rodrigues, Elisete Pains; Megías, Manuel; Hungria, Mariangela

    2010-08-01

    Rhizobium tropici is a diazotrophic microsymbiont of common bean (Phaseolus vulgaris L.) that encompasses important but still poorly studied tropical strains, and a recent significant contribution to the knowledge of the species was the publication of a genomic draft of strain PRF 81, which revealed several novel genes [Pinto et al. Funct Int Gen 9:263-270, 2009]. In this study, we investigated the transcription of nodC, nodG, and glgX genes, located in the nod operon of PRF 81 strain, by reverse-transcription quantitative PCR. All three genes showed low levels of transcription when the cells were grown until exponential growth phase in the presence of common-bean-seed exudates or of the root nod-gene inducer naringenin. However, when cells at the exponential phase of growth were incubated with seed exudates, transcription occurred after only 5 min, and nodC, nodG, and glgX were transcribed 121.97-, 14.86-, and 50.29-fold more than the control, respectively, followed by a rapid decrease in gene transcription. Much lower levels of transcription were observed in the presence of naringenin; furthermore, maximum transcription required 8 h of incubation for all three genes. In light of these results, the mechanisms of induction of the nodulation genes by flavonoids are discussed.

  11. Fine tuning of micropillar cavity modes through repetitive oxidations

    CERN Document Server

    Bakker, Morten P; Snijders, Henk; Truong, Tuan-Ahn; Petroff, Pierre M; Bouwmeester, Dirk; van Exter, Martin P

    2013-01-01

    Repetitive wet thermal oxidations of a tapered oxide aperture in a micropillar structure are demonstrated. After each oxidation step the con?fined optical modes are analyzed at room temperature. Three regimes are identi?fied. First, the optical con?finement increases when the aperture oxidizes towards the center. Then, the cavity modes shift by more than 30 nm, when the taper starts to oxidize through the center, leading to a decrease in the optical path length. Finally, the resonance frequency levels o?f, when the aperture is oxidized all the way through the micropillar, but confi?ned optical modes with a high quality factor remain. This repetitive oxidation technique therefore enables precise control of the optical cavity volume or wavelength.

  12. SI Engine with repetitive NS spark plug

    Science.gov (United States)

    Pancheshniy, Sergey; Nikipelov, Andrey; Anokhin, Eugeny; Starikovskiy, Andrey; Laplase Team; Mipt Team; Pu Team

    2013-09-01

    Now de-facto the only technology for fuel-air mixtures ignition in IC engines exists. It is a spark discharge of millisecond duration in a short discharge gap. The reason for such a small variety of methods of ignition initiation is very specific conditions of the engine operation. First, it is very high-pressure of fuel-air mixture - from 5-7 atmospheres in old-type engines and up to 40-50 atmospheres on the operating mode of HCCI. Second, it is a very wide range of variation of the oxidizer/fuel ratio in the mixture - from almost stoichiometric (0.8-0.9) at full load to very lean (φ = 0.3-0.5) mixtures at idle and/or economical cruising mode. Third, the high velocity of the gas in the combustion chamber (up to 30-50 m/s) resulting in a rapid compression of swirling inlet flow. The paper presents the results of tests of distributed spark ignition system powered by repetitive pulse nanosecond discharge. Dynamic pressure measurements show the increased pressure and frequency stability for nanosecond excitation in comparison with the standard spark plug. Excitation by single nanosecond high-voltage pulse and short train of pulses was examined. In all regimes the nanosecond pulsed excitation demonstrate a better performance.

  13. Comparing repetition-based melody segmentation models

    NARCIS (Netherlands)

    Rodríguez López, M.E.; de Haas, Bas; Volk, Anja

    2014-01-01

    This paper reports on a comparative study of computational melody segmentation models based on repetition detection. For the comparison we implemented five repetition-based segmentation models, and subsequently evaluated their capacity to automatically find melodic phrase boundaries in a corpus of 2

  14. Repetitions: A Cross-Cultural Study.

    Science.gov (United States)

    Murata, Kumiko

    1995-01-01

    This study investigated how repetition is used in conversation among native speakers of British English, native speakers of Japanese, and Japanese speakers of English. Five interactional functions of repetition (interruption-orientated, solidarity, silence-avoidance, hesitation, and reformulation) were identified, as well as the cultural factors…

  15. Repetitive transcranial magnetic stimulation in psychiatry

    Directory of Open Access Journals (Sweden)

    Biswa Ranjan Mishra

    2011-01-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a non-invasive and relatively painless tool that has been used to study various cognitive functions as well as to understand the brain-behavior relationship in normal individuals as well as in those with various neuropsychiatric disorders. It has also been used as a therapeutic tool in various neuropsychiatric disorders because of its ability to specifically modulate distinct brain areas. Studies have shown that repeated stimulation at low frequency produces long-lasting inhibition, which is called as long-term depression, whereas repeated high-frequency stimulation can produce excitation through long-term potentiation. This paper reviews the current status of rTMS as an investigative and therapeutic modality in various neuropsychiatric disorders. It has been used to study the cortical and subcortical functions, neural plasticity and brain mapping in normal individuals and in various neuropsychiatric disorders. rTMS has been most promising in the treatment of depression, with an overall milder adverse effect profile compared with electroconvulsive therapy. In other neuropsychiatric disorders such as schizophrenia, mania, epilepsy and substance abuse, it has been found to be useful, although further studies are required to establish therapeutic efficacy. It appears to be ineffective in the treatment of obsessive compulsive disorder. There is a paucity of studies of efficacy and safety of rTMS in pediatric and geriatric population. Although it appears safe, further research is required to optimize its efficacy and reduce the side-effects. Magnetic seizure therapy, which involves producing seizures akin to electroconvulsive therapy, appears to be of comparable efficacy in the treatment of depression with less cognitive adverse effects.

  16. 低频重复经颅磁刺激对脑卒中后记忆及认知功能的影响%Effect of Low-frequency Repetitive Transcranial Magnetic Stimulation on Memory and Cognition Impairment af-ter Stroke

    Institute of Scientific and Technical Information of China (English)

    芦海涛; 孙莉; 郭华珍; 张通

    2015-01-01

    目的:观察低频重复经颅磁刺激(rTMS)刺激右侧前额叶背外侧皮层对脑卒中患者认知及记忆功能的影响。方法脑卒中后记忆功能障碍患者40例,随机分为磁刺激组(n=19)和假刺激组(n=21),分别接受真假1 Hz rTMS治疗。所有患者在治疗前、治疗结束后和治疗结束2个月后分别用蒙特利尔认知评估量表(MoCA)中文版、洛文斯顿作业疗法认知评估(LOTCA)及行为记忆量表(RBMT)进行测评。结果两组在治疗后及治疗结束2个月时,MoCA、LOTCA及RBMT评分均有显著升高(P<0.001),磁刺激组改善程度明显优于假刺激组(P<0.01)。结论低频rTMS可以改善脑卒中后认知及记忆功能障碍。%Objective To investigate the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) on post-stroke dis-function of cognition and memory by stimulating right dorsolateral prefrontal cortex. Methods 40 patients were randomized into the rTMS (n=19) and sham (n=21) groups. The function of cognition and memory were measured before treatment, after treatment and 2 months post-treatment with Montreal Cognitive Assessment (MoCA), Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) and Riv-ermead Behaviour Memory Test (RBMT). Results All scores improved in both groups after treatment and 2 months post-treatment (P<0.001), and improved more in the rTMS group than in the sham group (P<0.01). Conclusion Low-frequency rTMS may improve the func-tion of memory and cognition after stoke.

  17. Strategies for Using Repetition as a Powerful Teaching Tool

    Science.gov (United States)

    Saville, Kirt

    2011-01-01

    Brain research indicates that repetition is of vital importance in the learning process. Repetition is an especially useful tool in the area of music education. The success of repetition can be enhanced by accurate and timely feedback. From "simple repetition" to "repetition with the addition or subtraction of degrees of freedom," there are many…

  18. Strategies for Using Repetition as a Powerful Teaching Tool

    Science.gov (United States)

    Saville, Kirt

    2011-01-01

    Brain research indicates that repetition is of vital importance in the learning process. Repetition is an especially useful tool in the area of music education. The success of repetition can be enhanced by accurate and timely feedback. From "simple repetition" to "repetition with the addition or subtraction of degrees of freedom," there are many…

  19. Repetition priming from moving faces.

    Science.gov (United States)

    Lander, Karen; Bruce, Vicki

    2004-06-01

    Recent experiments have suggested that seeing a familiar face move provides additional dynamic information to the viewer, useful in the recognition of identity. In four experiments, repetition priming was used to investigate whether dynamic information is intrinsic to the underlying face representations. The results suggest that a moving image primes more effectively than a static image, even when the same static image is shown in the prime and the test phases (Experiment 1). Furthermore, when moving images are presented in the test phase (Experiment 2), there is an advantage for moving prime images. The most priming advantage is found with naturally moving faces, rather than with those shown in slow motion (Experiment 3). Finally, showing the same moving sequence at prime and test produced more priming than that found when different moving sequences were shown (Experiment 4). The results suggest that dynamic information is intrinsic to the face representations and that there is an advantage to viewing the same moving sequence at prime and test.

  20. Basis Function Repetitive And Feedback Control With Application To A Particle Accelerator

    CERN Document Server

    Akogyeram, R A

    2002-01-01

    The thesis addresses three problem areas within repetitive control. Firstly, it addresses issues concerning the ability of repetitive control and feedback control systems to eliminate periodic disturbances occurring above the Nyquist frequency of the hardware. Methods are developed for decomposing and unfolding notch filter or comb filter feedback control so that disturbances above Nyquist frequency can be canceled. Phenomena affecting final error levels are discussed, including error in unfolding, coarseness of zero-order hold cancellation, and waterbed effects in the feedback control system frequency response for different sample rates. Secondly, matched basis function repetitive control laws are developed for batch mode and real time implementation to converge to zero tracking error in the presence of periodic disturbances. For both control methods, conditions are given that guarantee asymptotic and monotonic convergence. Stability tests are formulated to examine stability when the period of a disturbance ...

  1. Environmental conditions associated with repetitive behavior in a group of African elephants.

    Science.gov (United States)

    Hasenjager, Matthew J; Bergl, Richard A

    2015-01-01

    Repetitive movement patterns are commonly observed in zoo elephants. The extent to which these behaviors constitute a welfare concern varies, as their expression ranges from stereotypies to potentially beneficial anticipatory behaviors. Nevertheless, their occurrence in zoo animals is often viewed negatively. To better identify conditions that prompt their performance, observations were conducted on six African elephants (Loxodonta africana) at the North Carolina Zoo. Individuals spent most of their time engaged in feeding, locomotion, resting, and repetitive behavior. Both generalized estimating equation and zero-inflated negative binomial models were used to identify factors associated with increased rates of repetitive behavior. Time of day in conjunction with location on- or off-exhibit best explained patterns of repetitive behavior. Repetitive behaviors occurred at a lower rate in the morning when on-exhibit, as compared to afternoons on-exhibit or at any time of day off-exhibit. Increased repetitive behavior rates observed on-exhibit in the afternoon prior to the evening transfer and feeding were possibly anticipatory responses towards those events. In contrast, consistently elevated frequencies of repetitive behavior off-exhibit at all times of day could be related to differences in exhibit complexity between off-exhibit and on-exhibit areas, as well as a lack of additional foraging opportunities. Our study contributes valuable information on captive elephant behavior and represents a good example of how behavioral research can be employed to improve management of zoo animals.

  2. HD-03/ES: A Herbal Medicine Inhibits Hepatitis B Surface Antigen Secretion in Transfected Human Hepatocarcinoma PLC/PRF/5 Cells.

    Science.gov (United States)

    Varma, Sandeep R; Sundaram, R; Gopumadhavan, S; Vidyashankar, Satyakumar; Patki, Pralhad S

    2013-01-01

    HD-03/ES is a herbal formulation used for the treatment of hepatitis B. However, the molecular mechanism involved in the antihepatitis B (HBV) activity of this drug has not been studied using in vitro models. The effect of HD-03/ES on hepatitis B surface antigen (HBsAg) secretion and its gene expression was studied in transfected human hepatocarcinoma PLC/PRF/5 cells. The anti-HBV activity was tested based on the inhibition of HBsAg secretion into the culture media, as detected by HBsAg-specific antibody-mediated enzyme assay (ELISA) at concentrations ranging from 125 to 1000  μ g/mL. The effect of HD-03/ES on HBsAg gene expression was analyzed using semiquantitative multiplex RT-PCR by employing specific primers. The results showed that HD-03/ES suppressed HBsAg production with an IC50 of 380  μ g/mL in PLC/PRF/5 cells for a period of 24 h. HD-03/ES downregulated HBsAg gene expression in PLC/PRF/5 cells. In conclusion, HD-03/ES exhibits strong anti-HBV properties by inhibiting the secretion of hepatitis B surface antigen in PLC/PRF/5 cells, and this action is targeted at the transcription level. Thus, HD-03/ES could be beneficial in the treatment of acute and chronic hepatitis B infections.

  3. Comparison of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factor (CGF) in rabbit-skull defect healing.

    Science.gov (United States)

    Kim, Tae-Hoon; Kim, Sung-Hee; Sándor, George K; Kim, Yong-Deok

    2014-05-01

    The objective of this study was to evaluate the effect of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factor (CGF) on bone healing. Twelve rabbits were included in this randomized, blinded, prospective study. 15-mm×10-mm-sized defects were created in the parietal bone, filled with PRP, PRF, CGF, and void. The bone mineral density and bone volume were analyzed with microscopic computed tomography (micro-CT) and histomorphometrics at the 6th and 12th week. In micro-CT analysis, bone mineral density and bone volume were greater in the experimental group than in controls at both 6th and 12th week, but not among the experimental groups. Similarly, histomorphometric examination revealed that more bone formation was seen in the experimental group. The addition of PRP, PRF, and CGF had significantly increased bone formation at the 6th week. The effect of PRP, PRF, and CGF was similar and may be useful in the future to increase the success rate of bone grafting. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Metabolic Genetic Screens Reveal Multidimensional Regulation of Virulence Gene Expression in Listeria monocytogenes and an Aminopeptidase That Is Critical for PrfA Protein Activation.

    Science.gov (United States)

    Friedman, Sivan; Linsky, Marika; Lobel, Lior; Rabinovich, Lev; Sigal, Nadejda; Herskovits, Anat A

    2017-06-01

    Listeria monocytogenes is an environmental saprophyte and intracellular bacterial pathogen. Upon invading mammalian cells, the bacterium senses abrupt changes in its metabolic environment, which are rapidly transduced to regulation of virulence gene expression. To explore the relationship between L. monocytogenes metabolism and virulence, we monitored virulence gene expression dynamics across a library of genetic mutants grown under two metabolic conditions known to activate the virulent state: charcoal-treated rich medium containing glucose-1-phosphate and minimal defined medium containing limiting concentrations of branched-chain amino acids (BCAAs). We identified over 100 distinct mutants that exhibit aberrant virulence gene expression profiles, the majority of which mapped to nonessential metabolic genes. Mutants displayed enhanced, decreased, and early and late virulence gene expression profiles, as well as persistent levels, demonstrating a high plasticity in virulence gene regulation. Among the mutants, one was noteworthy for its particularly low virulence gene expression level and mapped to an X-prolyl aminopeptidase (PepP). We show that this peptidase plays a role in posttranslational activation of the major virulence regulator, PrfA. Specifically, PepP mediates recruitment of PrfA to the cytoplasmic membrane, a step identified as critical for PrfA protein activation. This study establishes a novel step in the complex mechanism of PrfA activation and further highlights the cross regulation of metabolism and virulence. Copyright © 2017 American Society for Microbiology.

  5. Antimicrobial medium- and long-chain free fatty acids prevent PrfA-dependent activation of virulence genes in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Sternkopf Lillebæk, Eva Maria; Lambert Nielsen, Stine; Scheel Thomasen, Rikke

    2017-01-01

    The foodborne pathogen Listeria monocytogenes is the causative agent of the invasive disease listeriosis. Infection by L. monocytogenes involves bacterial crossing of the intestinal barrier and intracellular replication in a variety of host cells. The PrfA protein is the master regulator of virul...

  6. Precision markedly attenuates repetitive lift capacity.

    Science.gov (United States)

    Collier, Brooke R; Holland, Laura; McGhee, Deirdre; Sampson, John A; Bell, Alison; Stapley, Paul J; Groeller, Herbert

    2014-01-01

    This study investigated the effect of precision on time to task failure in a repetitive whole-body manual handling task. Twelve participants were required to repetitively lift a box weighing 65% of their single repetition maximum to shoulder height using either precise or unconstrained box placement. Muscle activity, forces exerted at the ground, 2D body kinematics, box acceleration and psychophysical measures of performance were recorded until task failure was reached. With precision, time to task failure for repetitive lifting was reduced by 72%, whereas the duration taken to complete a single lift and anterior deltoid muscle activation increased by 39% and 25%, respectively. Yet, no significant difference was observed in ratings of perceived exertion or heart rate at task failure. In conclusion, our results suggest that when accuracy is a characteristic of a repetitive manual handling task, physical work capacity will decline markedly. The capacity to lift repetitively to shoulder height was reduced by 72% when increased accuracy was required to place a box upon a shelf. Lifting strategy and muscle activity were also modified, confirming practitioners should take into consideration movement precision when evaluating the demands of repetitive manual handling tasks.

  7. Experimental study on autologous iliac bone transplantation combined with PRF%自体髂骨复合PRF修复牙槽嵴裂的实验研究

    Institute of Scientific and Technical Information of China (English)

    周龙; 封兴华; 陆斌

    2013-01-01

    目的:将富血小板纤维蛋白(Platelet-rich fibrin,PRF)应用于牙槽嵴裂植骨手术,验证其是否能够减少植骨术后的骨吸收.方法:8~12月龄犬8只,以外科手术的方法制备双侧牙槽嵴裂模型,随机于两侧同期植入自体髂骨(对照组)及自体髂骨混合PRF(实验组).于术后当日、2个月、4个月时拍摄上颌骨CT,利用三维重建软件测量植骨区体积,计算骨吸收率.结果:术后2个月、4个月时实验组的骨吸收率明显小于对照组,行配对样本的t检验,P<0.01.结论:将PRF加入自体髂骨进行骨移植修复犬的牙槽嵴裂,在术后4个月的时间范围内,可以减少术后的骨吸收.%Objective We grafted the platelet-rich fibrin (PRF) mixed with autogenous iliac bone in the alveolar cleft and evaluated the bone resorption after operation. Methods 8 dogs (8-12 months) were created bilateral alveolar cleft by surgical operation, autogenous iliac bone(control group) and the PRF mixed with autogenous iliac bone(PRF group) were implanted into the defect of one side randomly and bone regeneration was investigated 2 months and 4 months after implantation. Results The bone resorption of the PRF group was lower than that of the control group at 2 months and 4 months,P<0.01. Conclusion Autogenous iliac bone grafting with PRF.which significantly reduces postoperative bone resorption on dog bilateral alveolar cleft model.

  8. Illusory sensation of movement induced by repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Mark Schram Christensen

    Full Text Available Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb movement and its associated somatosensory feedback. Afferent and efferent neural signalling was abolished in the arm with ischemic nerve block, and in the leg with spinal nerve block. Movement sensation was assessed following trains of high-frequency repetitive transcranial magnetic stimulation applied over primary motor cortex, dorsal premotor cortex, and a control area (posterior parietal cortex. Magnetic stimulation over primary motor cortex and dorsal premotor cortex produced a movement sensation that was significantly greater than stimulation over the control region. Movement sensation after dorsal premotor cortex stimulation was less affected by sensory and motor deprivation than was primary motor cortex stimulation. We propose that repetitive transcranial magnetic stimulation over dorsal premotor cortex produces a corollary discharge that is perceived as movement.

  9. Novel Use of PRF and PDT in the Management of Trauma Induced Root Resorption and Infrabony Defect.

    Science.gov (United States)

    Pruthi, Preeti Jain; Yadav, Neha; Nawal, Ruchika Roongta; Talwar, Sangeeta; Lamba, Arundeep Kaur

    2015-05-01

    Root resorption is a common squeal of traumatic injury to the dentition. Its progression can be minimized by early diagnosis and appropriate treatment. This case report presents the diagnosis and management of a case of trauma induced trio of apical root resorption, intraradicular root resorption and infrabony defect in maxillary central incisor. The main aim in treating such cases of resorption is to limit the inflammatory response at the periapical region so as to halt the resorptive process. To allow faster regeneration of the periodontal tissues, Platelet rich fibrin (PRF), a second generation platelet concentrate was used as an apical matrix over which MTA plug was given. The periodontal defect was managed with the help of localized antimicrobial photodynamic therapy (aPDT).

  10. Atypical presentation of NREM arousal parasomnia with repetitive episodes.

    Science.gov (United States)

    Trajanovic, N N; Shapiro, C M; Ong, A

    2007-08-01

    The case report describes a distinct variant of non-REM (Rapid Eye Movement) arousal parasomnia, sleepwalking type, featuring repetitive abrupt arousals, mostly from slow-wave sleep, and various automatisms and semi-purposeful behaviours. The frequency of events and distribution throughout the night presented as a continuous status of parasomnia ('status parasomnicus'). The patient responded well to treatment typically administered for adult NREM parasomnias, and after careful review of the clinical presentation, objective findings and treatment outcome, sleep-related epilepsy was ruled out in favour of parasomnia.

  11. 强制性诱导语言治疗联合低频重复经颅磁刺激对非流畅性失语的疗效%Effectiveness of constraint induced language therapy combined with low frequency repetitive transcranial magnetic stim-ulation for non-fluent aphasia

    Institute of Scientific and Technical Information of China (English)

    周秋敏; 丛芳; 沈滢; 殷稚飞; 张文通; 叶芊; 陈文莉; 单春雷

    2014-01-01

    目的:观察强制性诱导语言治疗(CILT)联合低频重复经颅磁刺激(rTMS)对非流畅性失语的语言功能和交流能力的影响。方法:40例失语症患者随机分为4组各10例,分别采用常规治疗(常规组)、常规治疗+CIL T (CILT组)、常规治疗+1Hz rTMS(rTMS组)及常规治疗+CILT+1Hz rTMS(联合组)治疗10d ,治疗前后进行西方失语症成套测验(WAB)的自发言语、听理解、复述及命名前4项及日常生活交流活动检查(CADL )评定语言功能和交流能力。结果:治疗10d后,联合组WAB各项功能评分及CADL评分均较治疗前、CILT 组及常规组明显提高(P<0.05),联合组WAB评分自发言语、听理解和命名3项及CADL评分均较rTMS组明显提高(P<0.05), WAB评分复述项联合组与rTMS组组间比较差异无统计学意义;rTMS组WAB各项功能评分及CADL评分均较治疗前及常规组提高更明显(P<0.05);CILT组WAB评分自发言语、听理解和命名3项及CADL评分均较治疗前及常规组明显提高(P<0.05);常规组WAB评分仅自发言语较治疗前有提高(P<0.05),CADL评分治疗前后比较差异无统计学意义。结论:强制性诱导疗法和低频重复性经颅磁刺激对非流畅型失语疗效优于常规治疗,两者联合运用疗效更优。%Objective:To observe the effects of constraint induced language therapy(CILT) combined with low fre-quency repetitive transcranial magnetic stimulation(rTMS) on language functions and communication skills of non-fluent aphasia patients .Methods:Forty patients were randomly assigned to four groups accepting conventional thera-py(conventional group) ,conventional therapy + CILT (CILT group) ,conventional therapy + 1 Hz rTMS (rTMS group) ,and conventional therapy+CILT+1 Hz rTMS(combined group) for 10 days ,respectively .Before and after therapy ,the language functions were evaluated with the

  12. Repetitive Bibliographical Information in Relational Databases.

    Science.gov (United States)

    Brooks, Terrence A.

    1988-01-01

    Proposes a solution to the problem of loading repetitive bibliographic information in a microcomputer-based relational database management system. The alternative design described is based on a representational redundancy design and normalization theory. (12 references) (Author/CLB)

  13. Computer-Related Repetitive Stress Injuries

    Science.gov (United States)

    ... on the shoulder Epicondylitis: elbow soreness often called "tennis elbow" Ganglion cyst: swelling or lump in the wrist ... Bones, Muscles, and Joints Carpal Tunnel Syndrome Medial Epicondylitis Repetitive Stress Injuries Contact Us Print Resources Send ...

  14. Understanding communicative actions: a repetitive TMS study.

    Science.gov (United States)

    Stolk, Arjen; Noordzij, Matthijs L; Volman, Inge; Verhagen, Lennart; Overeem, Sebastiaan; van Elswijk, Gijs; Bloem, Bas; Hagoort, Peter; Toni, Ivan

    2014-02-01

    Despite the ambiguity inherent in human communication, people are remarkably efficient in establishing mutual understanding. Studying how people communicate in novel settings provides a window into the mechanisms supporting the human competence to rapidly generate and understand novel shared symbols, a fundamental property of human communication. Previous work indicates that the right posterior superior temporal sulcus (pSTS) is involved when people understand the intended meaning of novel communicative actions. Here, we set out to test whether normal functioning of this cerebral structure is required for understanding novel communicative actions using inhibitory low-frequency repetitive transcranial magnetic stimulation (rTMS). A factorial experimental design contrasted two tightly matched stimulation sites (right pSTS vs left MT+, i.e., a contiguous homotopic task-relevant region) and tasks (a communicative task vs a visual tracking task that used the same sequences of stimuli). Overall task performance was not affected by rTMS, whereas changes in task performance over time were disrupted according to TMS site and task combinations. Namely, rTMS over pSTS led to a diminished ability to improve action understanding on the basis of recent communicative history, while rTMS over MT+ perturbed improvement in visual tracking over trials. These findings qualify the contributions of the right pSTS to human communicative abilities, showing that this region might be necessary for incorporating previous knowledge, accumulated during interactions with a communicative partner, to constrain the inferential process that leads to action understanding. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. SECEC Research Grant 2008 II: Use of platelet- and leucocyte-rich fibrin (L-PRF) does not affect late rotator cuff tendon healing: a prospective randomized controlled study.

    Science.gov (United States)

    Zumstein, Matthias A; Rumian, Adam; Thélu, Charles Édouard; Lesbats, Virginie; O'Shea, Kieran; Schaer, Michael; Boileau, Pascal

    2016-01-01

    Because the retear rate after rotator cuff repairs remains high, methods to improve healing are very much needed. Platelet-rich concentrates have been shown to enhance tenocyte proliferation and promote extracellular matrix synthesis in vitro; however, their clinical benefit remains unclear. We hypothesized that arthroscopic rotator cuff repair with leucocyte- and platelet-rich fibrin (L-PRF) results in better clinical and radiographic outcome at 12 months of follow-up than without L-PRF. Thirty-five patients were randomized to receive arthroscopic rotator cuff repair with L-PRF locally applied to the repair site (L-PRF+ group, n = 17) or without L-PRF (L-PRF- group, n = 18). Preoperative and postoperative clinical evaluation included the Subjective Shoulder Value, visual analog score for pain, Simple Shoulder Test, and Constant-Murley score. The anatomic watertight healing, tendon thickness, and tendon quality was evaluated using magnetic resonance arthrography at 12 months of follow-up. No complications were reported in either group. The mean Subjective Shoulder Value, Simple Shoulder Test, and Constant-Murley scores increased from preoperatively to postoperatively, showing no significant differences between the groups. Complete anatomic watertight healing was found in 11 of 17 in the L-PRF+ group and in 11 of 18 in the L-PRP- group (P = .73). The mean postoperative defect size (214 ± 130 mm(2) in the L-PRF+ group vs 161 ± 149 mm(2) in the L-PRF- group; P = .391) and the mean postoperative tendon quality according to Sugaya (L-PRF+ group: 3.0 ± 1.4, L-PRF- group: 3.0 ± 0.9) were similar in both groups at 12 months of follow-up. Arthroscopic rotator cuff repair with application of L-PRF yields no beneficial effect in clinical outcome, anatomic healing rate, mean postoperative defect size, and tendon quality at 12 months of follow-up. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  16. The effect of low frequency repetitive transcranial magnetic stimulation on acute cerebral infarction patients movement function recovery%低频重复经颅磁刺激对急性脑梗死患者运动功能恢复的影响

    Institute of Scientific and Technical Information of China (English)

    宁耀超; 孙辉

    2013-01-01

    目的 探讨低频重复经颅磁刺激(rTMS)对急性脑梗死患者运动功能恢复的影响,以期能为低频rTMS治疗急性脑梗死的深入研究及临床应用提供一定参考依据.方法 选取60例急性脑梗死伴单侧肢体运动功能障碍患者,按随机数字表法分为低频rTMS组与对照组,每组30例,两组均给予常规药物治疗及康复训练,低频rTMS组在以上治疗基础上加用低频rTMS治疗10d,观察两组患者治疗前、治疗后10d、治疗后40d时美国国立卫生院神经功能缺损评分(NIHSS)、Fugl-Meyer运动量表(FMA)评分及Barthel指数(BI)评分变化.结果 低频rTMS组治疗前NIHSS、BI评分和FMA评分分别为(16.44±3.29)、(36.69±5.97)、(31.06±7.43)分,对照组分别为(16.38±4.01)、(35.98±6.41)、(30.87±8.56)分,两组比较差异无统计学意义(P>0.05).低频rTMS组治疗后10d NIHSS评分、BI评分和FMA评分分别为(8.13±2.18)、(56.04±5.21)、(48.42±7.73)分,对照组分别为(11.23±1.97)、(50.12±4.88)、(42.12±8.61)分;低频rTMS组治疗后40d NIHSS、BI评分和FMA评分分别为(3.11±0.53)、(73.29±5.34)、(61.63±8.36)分,对照组分别为(5.62±0.98)、(63.96±4.46)、(52.45±7.61)分.两组治疗后10、40d NIHSS均较治疗前明显下降,BI及FMA评分均较治疗前明显升高,差异有统计学意义(P<0.05);低频rTMS组治疗后10、40d NIHSS、BI评分和FMA评分与对照组比较差异均有统计学意义(P<0.05).结论 低频rTMS对急性脑梗死患者运动功能恢复有明显的促进作用.%Objective To investigate low frequency repetitive transcranial magnetic stimulation (rTMS) on acute cerebral infarction (ACI) patients movement function recovery,in order to provide certain reference basis about the further research on low frequency rTMS treatment ACI and clinical application.Methods Sixty patients of ACI with unilateral limb movement function disorder were divided into low frequency rTMS group and control group by table of

  17. Exogenous hydrogen sulfide exerts proliferation/anti-apoptosis/angiogenesis/migration effects via amplifying the activation of NF-κB pathway in PLC/PRF/5 hepatoma cells.

    Science.gov (United States)

    Zhen, Yulan; Pan, Wanying; Hu, Fen; Wu, Hongfu; Feng, Jianqiang; Zhang, Ying; Chen, Jingfu

    2015-05-01

    Hydrogen sulfide (H2S) takes part in a diverse range of intracellular pathways and hss physical and pathological properties in vitro and in vivo. However, the effects of H2S on cancer are controversial and remain unclear. The present study investigates the effects of H2S on liver cancer progression via activating NF-κB pathway in PLC/PRF/5 hepatoma cells. PLC/PRF/5 hepatoma cells were pretreated with 500 µmol/l NaHS (a donor of H2S) for 24 h. The expression levels of CSE, CBS, phosphosphorylate (p)-NF-κB p65, caspase-3, COX-2, p-IκB and MMP-2 were measured by western blot assay. Cell viability was detected by cell counter kit 8 (CCK-8). Apoptotic cells were observed by Hoechst 33258 staining assay. The production level of H2S in cell culture medium was measured by using the sulfur-sensitive electrode method. The production of vascular endothelial growth factor (VEGF) was tested by enzyme-linked immunosorbent assay (ELISA). Our results showed that the production of H2S was dramatically increased in the PLC/PRF/5 hepatoma cells, compared with human LO2 hepatocyte cells group, along with the overexpression levels of CSE and CBS. Treatment of PLC/PRF/5 hepatoma cells with 500 µmol/l NaHS (a donor of H2S) for 24 h markedly increased the expression levels of CSE, CBS, p-IκB and NF-κB activation, leading to COX-2 and MMP-2 overexpression, and decreased caspase-3 production, as well as increased cell viability and decreased number of apoptotic cells. Otherwise, the production level of H2S and VEGF were also significantly increased. Furthermore, co-treatment of PLC/PRF/5 hepatoma cells with 500 µmol/l NaHS and 200 µmol/l PDTC for 24 h significantly overturned these indexes. The findings of the present study provide evidence that the NF-κB is involved in the NaHS-induced cell proliferation, anti-apoptisis, angiogenesis, and migration in PLC/PRF/5 hepatoma cells, and that the PDTC against the NaHS-induced effects were by inhibition of the NF-κB pathway.

  18. The Prevalence and Phenomenology of Repetitive Behavior in Genetic Syndromes

    Science.gov (United States)

    Moss, Joanna; Oliver, Chris; Arron, Kate; Burbidge, Cheryl; Berg, Katy

    2009-01-01

    We investigated the prevalence and phenomenology of repetitive behavior in genetic syndromes to detail profiles of behavior. The Repetitive Behaviour Questionnaire (RBQ) provides fine-grained identification of repetitive behaviors. The RBQ was employed to examine repetitive behavior in Angelman (N = 104), Cornelia de Lange (N = 101), Cri-du-Chat…

  19. Multi-Rate Fractional-Order Repetitive Control of Shunt Active Power Filter

    DEFF Research Database (Denmark)

    Xie, Chuan; Zhao, Xin; Savaghebi, Mehdi

    2017-01-01

    This paper presents a multi-rate fractional-order repetitive control (MRFORC) scheme for three-phase shunt active power filter (APF). The proposed APF control scheme includes an inner proportional-integral (PI) control loop with a sampling rate identical to switching frequency and an external plug-in...

  20. Acute Alcohol Effects on Repetition Priming and Word Recognition Memory with Equivalent Memory Cues

    Science.gov (United States)

    Ray, Suchismita; Bates, Marsha E.

    2006-01-01

    Acute alcohol intoxication effects on memory were examined using a recollection-based word recognition memory task and a repetition priming task of memory for the same information without explicit reference to the study context. Memory cues were equivalent across tasks; encoding was manipulated by varying the frequency of occurrence (FOC) of words…

  1. Likelihood methods and classical burster repetition

    CERN Document Server

    Graziani, C; Graziani, Carlo; Lamb, Donald Q

    1995-01-01

    We develop a likelihood methodology which can be used to search for evidence of burst repetition in the BATSE catalog, and to study the properties of the repetition signal. We use a simplified model of burst repetition in which a number N_{\\rm r} of sources which repeat a fixed number of times N_{\\rm rep} are superposed upon a number N_{\\rm nr} of non-repeating sources. The instrument exposure is explicitly taken into account. By computing the likelihood for the data, we construct a probability distribution in parameter space that may be used to infer the probability that a repetition signal is present, and to estimate the values of the repetition parameters. The likelihood function contains contributions from all the bursts, irrespective of the size of their positional errors --- the more uncertain a burst's position is, the less constraining is its contribution. Thus this approach makes maximal use of the data, and avoids the ambiguities of sample selection associated with data cuts on error circle size. We...

  2. Electromyographical Study on Muscle Fatigue in Repetitive Forearm Tasks

    Institute of Scientific and Technical Information of China (English)

    DAI Wentao; ZHAO Xiaorong; WANG Zhenglun; YANG Lei

    2007-01-01

    The purpose of this study was to examine whether repetitive muscle tasks in low weight load might influence the fatigue of forearm muscles, and to identify ergonomic risk factors of forearm muscle fatigue in these tasks. Sixteen healthy male volunteers performed eight wrist extensions in different frequency, weight and angle loads while being instructed to keep a dominant upper limb posture as constant as possible. Surface electromyograph (sEMG) was recorded from right extensors digitorium (ED), flexor carpi radialis (FCR), flexor carpi ulnaris (FCU) and extensor carpi ulnaris (ECU) during the task performance. Our results showed that mean power frequency (MPF) and median frequency (MF) values of ED, FCR and FCU were significantly lower (P<0.05) at high frequency load level than at low load level. However, MPF and MF values of ED were significantly lower (P<0.01) in higher load groups of frequency, angle and weight than in lower load groups. These results indicated that the fatigue of muscles varied in the same task, and the number-one risk factor of ECU, ED and FCR was angle load.

  3. Effects of Repetitive Transcranial Magnetic Stimulation in Performing Eye-Hand Integration Tasks: Four Preliminary Studies with Children Showing Low-Functioning Autism

    Science.gov (United States)

    Panerai, Simonetta; Tasca, Domenica; Lanuzza, Bartolo; Trubia, Grazia; Ferri, Raffaele; Musso, Sabrina; Alagona, Giovanna; Di Guardo, Giuseppe; Barone, Concetta; Gaglione, Maria P.; Elia, Maurizio

    2014-01-01

    This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and…

  4. Amalgamation of allogenic bone graft, platelet-rich fibrin gel, and PRF membrane in auto-transplantation of an impacted central incisor

    Directory of Open Access Journals (Sweden)

    Zainab Chaudhary

    2015-01-01

    Full Text Available "Social six" teeth refers to the maxillary incisors and canines that play a vital role in the appearance of an individual and absence of any one of them has a significant psycho-social impact. Hence, early treatment and rehabilitation of the same are extremely important. A multitude of treatment options ranging from orthodontic extrusion, extraction followed by implant placement, fixed partial denture, and auto-transplantation have been advocated. This case report discusses the unique amalgamation of platelet-rich fibrin (PRF, demineralized freeze-dried bone graft with use of PRF membrane during auto-transplantation of an impacted central incisor. The authors have focused on maximum usage of autogenous materials in the most economic and least invasive manner. Furthermore, this amalgamation has been used to provide rehabilitation in the least span of time.

  5. Amalgamation of allogenic bone graft, platelet-rich fibrin gel, and PRF membrane in auto-transplantation of an impacted central incisor.

    Science.gov (United States)

    Chaudhary, Zainab; Kumar, Yuvika Raj; Mohanty, Sujata; Khetrapal, Ambica

    2015-01-01

    "Social six" teeth refers to the maxillary incisors and canines that play a vital role in the appearance of an individual and absence of any one of them has a significant psycho-social impact. Hence, early treatment and rehabilitation of the same are extremely important. A multitude of treatment options ranging from orthodontic extrusion, extraction followed by implant placement, fixed partial denture, and auto-transplantation have been advocated. This case report discusses the unique amalgamation of platelet-rich fibrin (PRF), demineralized freeze-dried bone graft with use of PRF membrane during auto-transplantation of an impacted central incisor. The authors have focused on maximum usage of autogenous materials in the most economic and least invasive manner. Furthermore, this amalgamation has been used to provide rehabilitation in the least span of time.

  6. Contribution a l'etude du comportement de dalles de ponts en beton arme de barres en PRF soumises a des charges concentrees simulant les charges de roues

    Science.gov (United States)

    Bouguerra, Kheireddine

    Au cours des dernieres annees, la deterioration des structures en beton arme a pris une ampleur sans precedent, et ce, malgre le fait que leur duree de vie en service initialement prevue est loin d'etre atteinte. La corrosion de l'armature d'acier est un des principaux facteurs reduisant la duree de vie des ponts en beton arme d'acier. Par ailleurs, l'armature en materiaux composites de polymeres renforces de fibres (PRF) constitue une solution a l'armature metallique afin de pallier au probleme de la corrosion d'acier et a la deterioration des structures en beton arme. Aussi, les barres d'armature en materiaux composites de PRF possedent une resistance en traction elevee (environ 2 a 6 fois la limite elastique de l'acier d'armature conventionnel), ce qui leur permet de constituer un renforcement structural attrayant pour les structures en beton. Le comportement d'elements structuraux en beton arme de barres en PRF est different de ceux en beton arme de barres d'acier. En effet, les barres en PRF possedent un module d'elasticite relativement plus faible que celui de l'acier et ont des proprietes d'adherence differentes de celles des barres d'acier. L'utilisation des barres d'armature en PRF pour armer les dalles de tabliers de ponts se concretise de plus en plus avec l'avancement des recherches dans ce domaine. La recherche entamee dans le cadre de cette these s'inscrit dans un programme de travaux realises au sein de la Chaire de recherche CRSNG/Industrie sur les Materiaux composites novateurs en PRF pour les infrastructures au departement de genie civil a l'Universite de Sherbrooke. Le comportement de membrures en beton arme de PRF soumis a des sollicitations mecaniques constitue un des principaux axes de recherche. Dans le cadre de cette these, une serie d'essais a ete effectuee sur huit dalles de ponts a confinement interne a grande echelle. Les parametres des essais comprennent: (1) l'epaisseur de la dalle, (2) le type et le taux d'armature transversale de l

  7. Interspecific "common" repetitive DNA sequences in salamanders of the genus Plethodon.

    Science.gov (United States)

    Mizuno, S; Andrews, C; Macgregor, H C

    1976-10-12

    Intermediate repetitive sequences of Plethodon cinereus which comprised about 30% of the genomic DNA were isolated and iodinated with 125I. About 5% of the 125I-repetitive fraction hybridized with a large excess of DNA from P. dunni at Cot 20. About half of the 125I-DNA in the hybrids was resistant to extensive digestion with S-1 nuclease. The average molecular size of the S-1 nuclease-resistant fraction was about 100 nucleotide pairs. The melting temperature of the S-1 nuclease-resistant fraction was about 2 degrees lower than that of the corresponding fraction made with P. cinereus DNA. These results are taken to indicate the presence in the genomes of P. cinereus and P. dunni of evolutionarily stable "common" repetitive sequences. The average frequency of repetition of the common repetitive sequences is about 6,000 X in both species. The common repetitive fraction is also present in the genomes of other species of Plethodon, although the general populations of intermediate repetitive sequences are markedly different from one species to another. The cinereus--dunni common repetitive sequences could not be detected in plethodontids belonging to different tribes, nor in more distantly related amphibians. The profiles of binding of the common repetitive sequences to CsCl or CS2SO4-Ag+ density gradient fractions of P. dunni DNA suggested that these sequences consisted of heterogeneous components with respect to base compositions, and that they did not include large amounts of the genes for ribosomal RNA, 5S RNA, 4S RNA, or histone messenger RNA. In situ hybridization of the 3H-labelled intermediate repetitive sequences of P. cinereus to male meiotic chromosomes of the same species gave autoradiographs after an exposure of seven days showing all 14 chromosomes labelled. The pattern of labelling appeared not to be random, but was impossible to analyse on account of the irregular shapes and different degrees of stretching of diplotene and prometaphase chromosomes. In

  8. Relationship between repetitive firing and afterhyperpolarizations in human neocortical neurons.

    Science.gov (United States)

    Lorenzon, N M; Foehring, R C

    1992-02-01

    1. Human neocortical neurons fire repetitively in response to long depolarizing current injections. The slope of the relationship between average firing frequency and injected current (f-I slope) was linear or bilinear in these cells. The mean steady-state f-I slope (average of the last 500 ms of a 1-s firing episode) was 57.8 Hz/nA. The instantaneous firing rate decreased with time during a 1-s constant-current injection (spike frequency adaptation). Also, human neurons exhibited habituation in response to a 1-s current stimulus repeated every 2 s. 2. Afterhyperpolarizations (AHPs) reflect the active ionic conductances after action potentials. We studied AHPs with the use of intracellular recordings and pharmacological manipulations in the in vitro slice preparation to 1) gain insight into the ionic mechanisms underlying the AHPs and 2) elucidate the role that the underlying currents play in the functional behavior of human cortical neurons. 3. We have classified three AHPs in human neocortical neurons on the basis of their time courses: fast, medium, and slow. The amplitude of the AHPs was dependent on stimulus intensity and duration, number and frequency of spikes, and membrane potential. 4. The fast AHP had a reversal potential of -65 mV and was eliminated in extracellular Co2+, tetraethylammonium (TEA) or 4-aminopyridine, and intracellular TEA or CsCl. These manipulations also caused an increase in spike width. 5. The medium AHP had a reversal potential of -90 to -93 mV (22-24 mV hyperpolarized from mean resting potential). This AHP was reduced by Co2+, apamin, tubocurare, muscarine, norepinephrine (NE), and serotonin (5-HT). Pharmacological manipulations suggest that the medium AHP is produced in part by 1) a Ca-dependent K+ current and 2) a time-dependent anomalous rectifier (IH). 6. The slow AHP reversed at -83 to -87 mV (14-18 mV hyperpolarized from mean resting potential). This AHP was diminished by Co2+, muscarine, NE, and 5-HT. The pharmacology of the

  9. 星载合成孔径雷达不同工作模式下的PRF优化选取研究%Optimal selection of PRF for spaceborne synthetic aperture radar in different working mode

    Institute of Scientific and Technical Information of China (English)

    陈颖颖; 高阳; 何永华

    2012-01-01

    PRF is an important parameter in spaceborne synthetic aperture radar, which is affected by many factors, especially by emission interference, substellar point echo wave, range ambiguity and azimuth ambiguity. For these factors, the choice of the PRF is variant. On the basis of selecting PRF in common working mode, the selection of PRF in spotlight mode and sliding spotlight mode is discussed. The selection method of the PRF is proposed. At last, the simulation presents the method s effectiveness.%星载合成孔径雷达中,脉冲重复频率(PRF)是非常重要的参数.它的选择受到很多因素的影响,尤其是受到发射干扰、星下点回波、距离模糊以及方位模糊的影响,也正是受到这些因素的影响,导致在不同的工作模式下,PRF的选取有很大的差异.这里在研究常用的条带工作模式下PRF选取的基础上,讨论了聚束和滑动聚束模式下PRF选取的特殊性,给出了这两种工作模式下PRF选取的方法,并进行了仿真验证其有效性.

  10. Mechanical and degradation properties of advanced platelet-rich fibrin (A-PRF), concentrated growth factors (CGF), and platelet-poor plasma-derived fibrin (PPTF).

    Science.gov (United States)

    Isobe, Kazushige; Watanebe, Taisuke; Kawabata, Hideo; Kitamura, Yutaka; Okudera, Toshimitsu; Okudera, Hajime; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Tanaka, Takaaki; Kawase, Tomoyuki

    2017-12-01

    Fibrin clot membranes prepared from advanced platelet-rich fibrin (A-PRF) or concentrated growth factors (CGF), despite their relatively rapid biodegradability, have been used as bioactive barrier membranes for alveolar bone tissue regeneration. As the membranes degrade, it is thought that the growth factors are gradually released. However, the mechanical and degradable properties of these membranes have not well been characterized. The purpose of this study was to mechanically and chemically characterize these membranes. A-PRF and CGF clots were prepared from blood samples collected from non-smoking, healthy donors and were compressed to form 1-mm-thick membranes. Platelet-poor plasma-derived fibrin (PPTF) clots were prepared by adding bovine thrombin to platelet-poor plasma. A tensile test was performed at the speed of 1 mm/min. Morphology of the fibrin fibers was examined by SEM. A digestion test was performed in PBS containing trypsin and EDTA. In the tensile test, statistical difference was not observed in Young's modulus, strain at break, or maximum stress between A-PRF and CGF. In strain at break, PPTF was significantly weaker than CGF. Likewise, fibrin fiber thickness and crosslink density of PPTF were less than those of other membranes, and PPTF degraded faster than others. Although the centrifugal conditions are different, A-PRF and CGF are prepared by essentially identical mechanisms. Therefore, it is conceivable that both membranes have similar mechanical and chemical properties. Only PPTF, which was prepared by a different mechanism, was characterized as mechanically weaker and enzymatically more degradable.

  11. Use of leukocyte and platelet-rich fibrin (L-PRF) in periodontally accelerated osteogenic orthodontics (PAOO): Clinical effects on edema and pain.

    Science.gov (United States)

    Munoz, Francisco; Jiménez, Constanza; Espinoza, Daniela; Vervelle, Alain; Beugnet, Jacques; Haidar, Ziyad

    2016-04-01

    Demand for shorter treatment time is common in orthodontic patients. Periodontally Accelerated Osteogenic Orthodontics (PAOO) is a somewhat new surgical procedure which allows faster tooth movement via combining orthodontic forces with corticotomy and grafting of alveolar bone plates. Leukocyte and Platelet-Rich Fibrin (L-PRF) possess hard- and soft-tissue healing properties. Further, evidence of pain-inhibitory and anti-inflammatory potential is growing. Therefore, this study explores the feasibility, intra- and post-operative effects of using L-PRF in PAOO in terms of post-operative pain, inflammation, infection and post-orthodontic stability. A pilot prospective observational study involving a cohort of 11 patients was carried out. A Wilcko's modified PAOO technique with L-PRF (incorporated into the graft and as covering membrane) was performed with informed consent. Post-surgical pain, inflammation and infection were recorded for 10 days post-operatively, while the overall orthodontic treatment and post-treatment stability were followed up to 2 years. Accelerated wound healing with no signs of infection or adverse reactions was evident. Post-surgical pain was either "mild" (45.5%) or "moderate" (54.5%). Immediate post-surgical inflammation was either "mild" (89.9%) or "moderate" (9.1%). Resolution began on day 4 where most patients experienced either "mild" or no inflammation (72.7% and 9.1%, respectively). Complete resolution was achieved in all patients by day 8. The average orthodontic treatment time was 9.3 months. All cases were deemed stable for 2 years. L-PRF is simple and safe to use in PAOO. Combination with traditional bone grafts potentially accelerates wound healing and reduces post-surgical pain, inflammation, infection without interfering with tooth movement and/or post-orthodontic stability, over a 2 years period; thus alleviating the need for analgesics and anti-inflammatory medications. Periodontally accelerated osteogenic orthodontics

  12. To evaluate the clinical effects of PRF (Platelet-Rich-Fibrin) membranes in gingival recessions%富血小板纤维蛋白膜(PRF)治疗牙龈退缩的临床效果评价

    Institute of Scientific and Technical Information of China (English)

    裴延平; 林松杉; 章禾

    2015-01-01

    目的:采用Choukroun's富血小板纤维蛋白膜(PRF膜)手术治疗牙龈退缩,对治疗前后的临床效果进行评价. 方法:选取有牙龈退缩且有意愿进行PRF手术治疗的MillerⅠ~Ⅱ度患者10例,采用PRF手术,在术前、术后不同时间点(术后3、6、12个月)分别测量牙周袋深度、附着龈宽度、附着丧失,对比治疗前后的临床效果.结果:牙周袋深度术前术后无显著性差异(P>0.05);角化龈宽度增加,术前与术后各组之间有显著性差异(P0.05);The width keratinized gingival is increasing,A signifi-cant change in it after operation as compared with every group before operation (P <0.05);To cover part or all of root sur-face,A significant change after operation as compared with every group before operation(P<0.05). Conclusion:For gingival Recessions,It can be achieved a better Clinical effects by Platelet-Rich-Fibrin(PRF) Membranes.

  13. 低频重复经颅磁刺激治疗对卒中后抑郁患者认知和日常生活能力的影响%Effects of Low-frequency Repetitive Transcranial Magnetic Stimulation on Cognitive Function and Daily Life Ability in Patients with Post Stroke Depression

    Institute of Scientific and Technical Information of China (English)

    李克娇

    2015-01-01

    Objective: To explore the effects of low-frequency repetitive transcranial magnetic stimulation (r-TMS) on cognitive function and daily life ability of patients with post stroke depression (PSD). Methods: One-hundred and twenty-eight patients with PSD and mild cognitive impairment were enrolled and randomly divided into control group and r-TMS group with 64 cases in each group. Foundation treatment such as nerve nutrition, dilate blood ves-sels, early limb function rehabilitation, psychological counseling and antidepressant treatment were implemented in the control group. Cases in r-TMS group were treated with low-frequency r-TMS on the basis of foundation treat-ment for 8 weeks. The degree of depression were evaluated by using Hamilton depression scale (HAMD)-17; the cognitive function were evaluated by using mini-mental state examination (MMSE), and daily life ability were eval-uated by using Barthel index (BI) before and 4 and 8 weeks after treatment in two groups. Results: There were no difference in HAMD and MMSE scores and BI between two the groups (P>0.05) before treatment. After treatment, both groups showed lower HAMD scores as well as higher MMSE scores and BI than those before treatment (P<0.05). The scores of HAMD, MMSE and BI were improved more significantly in r-TMS group than those in control group (P<0.05 or 0.01). No serious adverse event was found in r-TMS group. Conclusion: Low-frequency r-TMS is an effective and safe therapy for patients with PSD, which can relieve depression and improve the cognitive func-tion and daily life ability.%目的:探讨低频重复经颅磁刺激(rTMS)治疗对卒中后抑郁(PSD)患者认知和日常生活能力的影响。方法:PSD 伴轻度认知障碍患者128例随机分为对照组和 r-TMS 组,各64例。对照组给予常规药物治疗及早期肢体功能康复、心理疏导和抗抑郁治疗;r-TMS 组在对照组治疗基础上加用低频 r-TMS 治疗。疗程均为8周。

  14. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai, David,; Lacoste, Deanna,; Laux, C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  15. 肝星状细胞条件培养基对肝癌细胞PLC/PRF/5耐药性的影响及其机制%Effect of hepatic stellate cell condition medium on chemo-resistance of hepatocellular carcinoma PLC/PRF/5 cells and its mechanism

    Institute of Scientific and Technical Information of China (English)

    喻国锋; 井莹莹; 寇兴瑞; 李蓉; 吴孟超; 卫立辛

    2013-01-01

    目的:探讨肝星状细胞条件培养基(hepatic stellate cell conditioned medium,HSC-CM)对人肝癌PLC/PRF/5细胞耐药性的影响及其可能的机制.方法:用无血清RPMI 1640培养肝星状细胞LX-2,使其在缺营养的环境下活化,收集其条件培养上清即为HSC-CM.PLC/PRF/5细胞在HSC-CM条件下培养24 h后,顺铂处理12 h或24 h,采用流式细胞术检测PLC/PRF/5细胞的凋亡情况,MTT法检测PLC/PRF/5细胞的增殖,real-time PCR检测PLC/PRF/5细胞上皮间质转化(epithelial mesenchymal transition,EMT)相关基因的表达水平.结果:顺铂组12和24h两个时间点PLC/PRF/5细胞的凋亡率为(22.34±1.12)%和(26.78±1.56)%;HSC-CM+顺铂组细胞的凋亡率为(17.22±1.42)%和(21.52±1.76)%,顺铂组细胞凋亡率显著高于HSC-CM+顺铂组(P<0.05).同在这两个时间点,顺铂组和HSC-CM+顺铂组PLC/PRF/5细胞的增殖活性分别为(68.65±2.56)%和(79.47 ±1.43)%,(46.54 ±3.65)%和(62.77±2.89)%,HSC-CM+顺铂组细胞增殖活性均高于顺铂组(P<0.05).Real-time PCR结果显示,与顺铂组相比较,HSC-CM+顺铂组PLC/PRF/5细胞中上皮标记物钙黏蛋白(E-cadherin)的表达下降(P<0.05),而间质细胞标记物神经黏附素(N-cadherin)、波形蛋白(vimentin)以及EMT相关转录因子Snail和ZEB1的表达显著上调(P<0.01).结论:HSC-CM可能通过诱导PLC/PRF/5细胞发生EMT,从而增强PLC/PRF/5细胞对顺铂的抵抗作用.

  16. Hepatitis E genotype 4 virus from feces of monkeys infected experimentally can be cultured in PLC/PRF/5 cells and upregulate host interferon-inducible genes.

    Science.gov (United States)

    Zhang, Feng; Qi, Ying; Harrison, Tim J; Luo, Baobin; Zhou, Yan; Li, Xiuhua; Song, Aijing; Huang, Weijin; Wang, Youchun

    2014-10-01

    The understanding of the interaction between hepatitis E virus (HEV) and its host cells has been impeded greatly by the absence of a cell culture system. In this study, an efficient cultivation method was developed in PLC/PRF/5 cells for HEV genotype 4 from the feces of monkeys infected experimentally. Compared to minimal essential medium (MEM), mixed Dulbecco's Modified Eagle's Medium (DMEM)/M199 improved the infection efficiency of HEV in PLC/PRF/5 cells. The incubation time and temperature were set at 6 hr and 40°C, respectively. Compared to a 100% ELISA positive ratio (EPR) of 1 × 10(6)  copies/ml HEV inoculated flasks, the ELISA positive ratio was 100%, 75%, 37.5%, and 100% for flasks inoculated with HEV incubated for 30 min under the conditions of pH 3.0, pH 11.0, 56°C and delipidation treatment, respectively. Gene expression profiles of HEV inoculated and control PLC/PRF/5 cells were assayed using a microarray. Four interferon-inducible genes, IFI27, IFI6, Mx1, and CMPK2, were up-regulated during HEV-infection. Furthermore, the replication of HEV was inhibited at 3-14 days after treatment with 500 IU/ml IFN-α2b.

  17. Platelet-Rich Fibrin-PRF in Dental Implant%富血小板纤维蛋白-PRF在口腔种植中的应用

    Institute of Scientific and Technical Information of China (English)

    王少华; 董卫华

    2016-01-01

    Tissue regeneration need growth factors, osteogenic cells, scaffolds and good blood supply. Wherein platelet rich fibrin (platelet-rich fibrin, PRF) platelet rich and various cytokines, with soft and hard tissue regeneration capacity of good promotion. Oral Implantology in patients with clinical situations many alveolar bone defect or lack of, PRF can promote alveolar bone defects, increased alveolar bone, soft tissue implants promote healing, inflammation around the implant treatment.%组织再生需要生长因子﹑成骨相关细胞﹑支架材料和良好的血供。其中富血小板纤维蛋白(platelet-rich fibrin,PRF)富含血小板及各种细胞因子,具有良好的促进软﹑硬组织再生的能力。临床口腔种植患者中有很多牙槽骨缺损或不足的情况﹐PRF可促进牙槽骨缺损修复﹐增高牙槽骨﹐促进种植体周围软组织愈合﹐治疗种植体周围炎。

  18. Application of the optimized decoupling methodology for the construction of a skeletal primary reference fuel (PRF mechanism focusing on engine-relevant conditions

    Directory of Open Access Journals (Sweden)

    Yachao eChang

    2015-09-01

    Full Text Available For the multi-dimensional simulation of the engines with advanced compression-ignition combustion strategies, a practical and robust chemical kinetic mechanism is highly demanded. Decoupling methodology is effective for the construction of skeletal mechanisms for long-chain alkanes. To improve the performance of the decoupling methodology, further improvements are introduced based on recent theoretical and experimental works. The improvements include: (1 updating the H2/O2 sub-mechanism; (2 refining the rate constants in the HCO/CH3/CH2O sub-mechanism; (3 building a new reduced C2 sub-mechanism; and (4 improving the large-molecule sub-mechanism. With the improved decoupling methodology, a skeletal primary reference fuel (PRF mechanism is developed. The mechanism is validated against the experimental data in shock tubes, jet-stirred reactors, premixed and counterflow flames for various PRF fuels covering the temperature range of 500–1450 K, the pressure range of 1–55 atm, and the equivalence ratio range of 0.25¬–1.0. Finally, the skeletal mechanism is coupled with a multi-dimensional computational fluid dynamics model to simulate the combustion and emission characteristics of homogeneous charge compression ignition (HCCI engines fueled with iso-octane and PRF. Overall, the agreements between the experiment and prediction are satisfactory.

  19. Microbicidal properties of Leukocyte- and Platelet-Rich Plasma/Fibrin (L-PRP/L-PRF): new perspectives.

    Science.gov (United States)

    Cieslik-Bielecka, A; Dohan Ehrenfest, D M; Lubkowska, A; Bielecki, T

    2012-01-01

    Platelets, as main actors of the first stage of the healing process, play an important role in tissue repair. Their granules contain many active substances, particularly over 30 growth factors with significant effects on the resident cells at the site of injury, such as mesenchymal stem cells, chondrocytes, fibroblasts, osteoblasts. This potential may be increased by the concentration of the platelets, using platelet-rich plasma/fibrin products. In the four families of platelet concentrates, 2 families contain also significant concentrations of leukocytes: L-PRP (Leukocyte- and Platelet-Rich Plasma) and L-PRF (Leukocyte- and Platelet-Rich Fibrin). Inductive properties of platelet concentrates were widely described. However, they present also antimicrobial effects. The antibacterial effects of L-PRP were highlighted in only a few in vitro studies. Strong activity comparable to gentamicin and oxacillin for L-PRP against methicillin susceptible Staphylococcus aureus (MSSA) was already demonstrated. L-PRP also inhibited the growth of methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli. Some authors also reported clinical observations about the reduction of infections and the induction of healing processes after the use of platelet concentrates in cardiac, orthopaedic, oral and maxillofacial surgery. However, very little is yet known about the antibacterial effects of these concentrates. In this manuscript, the current data about the antimicrobial agents and cells present in the platelet-rich plasma/fibrin are highlighted and discussed, in order to introduce this new key chapter of the platelet concentrate technology history.

  20. Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful.

    Science.gov (United States)

    Ryana, Haneet Kour; Srinath, Rashmi; Prakash, Shobha

    2016-06-01

    Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes.

  1. Multitargeting and antimetastatic potentials of silibinin in human HepG-2 and PLC/PRF/5 hepatoma cells.

    Science.gov (United States)

    Ghasemi, Reza; Ghaffari, Seyed H; Momeny, Majid; Pirouzpanah, Saeed; Yousefi, Mehdi; Malehmir, Mohsen; Alimoghaddam, Kamran; Ghavamzadeh, Ardeshir

    2013-01-01

    Hepatocellular carcinoma (HCC) is the most common sort of primary liver malignancy with poor prognosis. This study aimed at examining the effects of silibinin (a putative antimetastatic agent) on some transcriptional markers mechanistically related to HCC recurrence and metastasis in HepG-2 [hepatitis B virus (HBV)-negative and P53 intact) and PLC/PRF/5 (HBV-positive and P53 mutated) cells. The expression of 27 genes in response to silibinin was evaluated by real-time RT-PCR. The MMP gelatinolytic assay and microculture tetrazolium test (MTT) were tested. Silibinin was capable of suppressing the transcriptional levels of ANGPT2, ATP6L, CAP2, CCR6, CCR7, CLDN-10, cortactin, CXCR4, GLI2, HK2, ID1, KIAA0101, mortalin, PAK1, RHOA, SPINK1, and STMN1 as well as the enzymatic activity of MMP-2 but promoted the transcripts of CREB3L3, DDX3X, and PROX1 in both cells. Some significant differences between the cells in response to silibinin were detected that might be related to the differences of the cells in terms of HBV infection and/or P53 mutation, suggesting the possible influence of silibinin on HCC through biological functions of these 2 prognostic factors. In conclusion, our findings suggest that silibinin could potentially function as a multitargeting antimetastatic agent and might provide new insights for HCC therapy particularly for HBV-related and/or P53-mutated HCCs.

  2. Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful

    Science.gov (United States)

    Srinath, Rashmi; Prakash, Shobha

    2016-01-01

    Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes. PMID:27504421

  3. The neurobiology of repetitive behavior : of mice…

    NARCIS (Netherlands)

    Langen, Marieke; Kas, Martien J H; Staal, Wouter G; van Engeland, Herman; Durston, Sarah

    2011-01-01

    Repetitive and stereotyped behavior is a prominent element of both animal and human behavior. Similar behavior is seen across species, in diverse neuropsychiatric disorders and in key phases of typical development. This raises the question whether these similar classes of behavior are caused by simi

  4. Large-scale detection of repetitions.

    Science.gov (United States)

    Smyth, W F

    2014-05-28

    Combinatorics on words began more than a century ago with a demonstration that an infinitely long string with no repetitions could be constructed on an alphabet of only three letters. Computing all the repetitions (such as ∙∙∙TTT ∙∙∙ or ∙∙∙ CGACGA ∙∙∙ ) in a given string x of length n is one of the oldest and most important problems of computational stringology, requiring time in the worst case. About a dozen years ago, it was discovered that repetitions can be computed as a by-product of the Θ(n)-time computation of all the maximal periodicities or runs in x. However, even though the computation is linear, it is also brute force: global data structures, such as the suffix array, the longest common prefix array and the Lempel-Ziv factorization, need to be computed in a preprocessing phase. Furthermore, all of this effort is required despite the fact that the expected number of runs in a string is generally a small fraction of the string length. In this paper, I explore the possibility that repetitions (perhaps also other regularities in strings) can be computed in a manner commensurate with the size of the output.

  5. Verbal Repetitions and Echolalia in Alzheimer's Discourse

    Science.gov (United States)

    Da Cruz, Fernanda Miranda

    2010-01-01

    This article reports on an investigation of echolalic repetition in Alzheimer's disease (AD). A qualitative analysis of data from spontaneous conversations with MHI, a woman with AD, is presented. The data come from the DALI Corpus, a corpus of spontaneous conversations involving subjects with AD. This study argues that echolalic effects can be…

  6. Neurobehavioural Correlates of Abnormal Repetitive Behaviour

    Directory of Open Access Journals (Sweden)

    R. A. Ford

    1991-01-01

    Full Text Available Conditions in which echolalia and echopraxia occur are reviewed, followed by an attempt to elicit possible mechanisms of these phenomena. A brief description of stereotypical and perseverative behaviour and obsessional phenomena is given. It is suggested that abnormal repetitive behaviour may occur partly as a result of central dopaminergic dysfunction.

  7. Reducing Repetitive Speech: Effects of Strategy Instruction.

    Science.gov (United States)

    Dipipi, Caroline M.; Jitendra, Asha K.; Miller, Judith A.

    2001-01-01

    This article describes an intervention with an 18-year-old young woman with mild mental retardation and a seizure disorder, which focused on her repetitive echolalic verbalizations. The intervention included time delay, differential reinforcement of other behaviors, and self-monitoring. Overall, the intervention was successful in facilitating…

  8. Verbal Repetitions and Echolalia in Alzheimer's Discourse

    Science.gov (United States)

    Da Cruz, Fernanda Miranda

    2010-01-01

    This article reports on an investigation of echolalic repetition in Alzheimer's disease (AD). A qualitative analysis of data from spontaneous conversations with MHI, a woman with AD, is presented. The data come from the DALI Corpus, a corpus of spontaneous conversations involving subjects with AD. This study argues that echolalic effects can be…

  9. Effects of high frequency repetitive transcranial magnetic stimulation on emotional disorders and P300 of patients with Parkinson's disease%高频重复经颅磁刺激对帕金森病患者情绪障碍及P300电位的影响

    Institute of Scientific and Technical Information of China (English)

    郑秀琴; 于苏文; 陈升东; 蒋建波

    2013-01-01

    研究背景以往研究显示高频重复经颅磁刺激可以明显改善帕金森病患者运动功能,但帕金森病晚期非运动性症状给患者带来更为严重的影响,因此研究高频重复经颅磁刺激治疗帕金森病患者情绪和认知功能障碍等非运动性症状的临床疗效具有重要意义.方法共纳入65例诊断明确的帕金森病患者,根据统一帕金森病评价量表(UPDRS)、汉密尔顿焦虑量表(HAMA)、汉密尔顿抑郁量表(HAMD)和P300波,评价高频重复经颅磁刺激对患者精神行为和情绪、日常生活活动能力及运动功能的改善作用.结果与治疗前相比,帕金森病患者UPDRS总评分(t=10.872,P=0.000)和UPDRSⅠ(t=4.538,P:0.023)、UPDRS Ⅱ(t=8.846,P=0.012)、UPDRS Ⅲ(t=9.114,P=0.000)评分降低.患者焦虑和抑郁发生率由治疗前的52.46%(32/61)降至29.51%(18/61),认知功能障碍发生率由治疗前的42.62%(26/61)降至32.79%(20/61),HAMA(t=3.692,P=0.000)和HAMD(t=4.241,P=0.000)评分显著降低,但幻觉发生率由治疗前的18.03%(11/61)升至29.51%(18161).P300波潜伏期(t=5.924,P=0.000)和波幅(t=8.512,P=0.000)与治疗前比较,差异均有统计学意义.结论高频重复经颅磁刺激能够减轻帕金森病患者焦虑和抑郁状态,改善其认知功能.%Background Previous studies revealed that repetitive transcranial magnetic stimulation (rTMS) can obviously improve the motor function of Parkinson's disease (PD) patients. Since the non-motor symptoms of late stage PD can induce worse impacts on patients, it is important to investigate the clinical effects of high frequency rTMS on non- motor symptoms including emotional and cognitive disorders of PD patients. Methods Sixty - five patients with PD received rTMS therapy. Unified Parkinson's Disease Rating Scale (UPDRS), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD) and P300 before and after treatment were recorded to assess the effect of rTMS on patient's emotions, abilities of

  10. Leukocyte- and platelet-rich fibrin (L-PRF) for long-term delivery of growth factor in rotator cuff repair: review, preliminary results and future directions.

    Science.gov (United States)

    Zumstein, Matthias A; Berger, Simon; Schober, Martin; Boileau, Pascal; Nyffeler, Richard W; Horn, Michael; Dahinden, Clemens A

    2012-06-01

    Surgical repair of the rotator cuff repair is one of the most common procedures in orthopedic surgery. Despite it being the focus of much research, the physiological tendon-bone insertion is not recreated following repair and there is an anatomic non-healing rate of up to 94%. During the healing phase, several growth factors are upregulated that induce cellular proliferation and matrix deposition. Subsequently, this provisional matrix is replaced by the definitive matrix. Leukocyte- and platelet-rich fibrin (L-PRF) contain growth factors and has a stable dense fibrin matrix. Therefore, use of LPRF in rotator cuff repair is theoretically attractive. The aim of the present study was to determine 1) the optimal protocol to achieve the highest leukocyte content; 2) whether L-PRF releases growth factors in a sustained manner over 28 days; 3) whether standard/gelatinous or dry/compressed matrix preparation methods result in higher growth factor concentrations. 1) The standard L-PRF centrifugation protocol with 400 x g showed the highest concentration of platelets and leukocytes. 2) The L-PRF clots cultured in medium showed a continuous slow release with an increase in the absolute release of growth factors TGF-β1, VEGF and MPO in the first 7 days, and for IGF1, PDGF-AB and platelet activity (PF4=CXCL4) in the first 8 hours, followed by a decrease to close to zero at 28 days. Significantly higher levels of growth factor were expressed relative to the control values of normal blood at each culture time point. 3) Except for MPO and the TGFβ-1, there was always a tendency towards higher release of growth factors (i.e., CXCL4, IGF-1, PDGF-AB, and VEGF) in the standard/gelatinous- compared to the dry/compressed group. L-PRF in its optimal standard/gelatinous-type matrix can store and deliver locally specific healing growth factors for up to 28 days and may be a useful adjunct in rotator cuff repair.

  11. Pto- and Prf-mediated recognition of AvrPto and AvrPtoB restricts the ability of diverse pseudomonas syringae pathovars to infect tomato.

    Science.gov (United States)

    Lin, Nai-Chun; Martin, Gregory B

    2007-07-01

    The molecular basis underlying the ability of pathogens to infect certain plant species and not others is largely unknown. Pseudomonas syringae is a useful model species for investigating this phenomenon because it comprises more than 50 pathovars which have narrow host range specificities. Tomato (Solanum lycopersicum) is a host for P. syringae pv. tomato, the causative agent of bacterial speck disease, but is considered a nonhost for other P. syringae pathovars. Host resistance in tomato to bacterial speck disease is conferred by the Pto protein kinase which acts in concert with the Prf nucleotide-binding lucine-rich repeat protein to recognize P. syringae pv. tomato strains expressing the type III effectors AvrPto or AvrPtoB (HopAB2). The Pto and Prf genes were isolated from the wild tomato species S. pimpinellifolium and functional alleles of both of these genes now are known to exist in many species of tomato and in other Solanaceous species. Here, we extend earlier reports that avrPto and avrPtoB genes are widely distributed among pathovars of P. syringae which are considered nonhost pathogens of tomato. This observation prompted us to examine the possibility that recognition of these type III effectors by Pto or Prf might contribute to the inability of many P. syringae pathovars to infect tomato species. We show that 10 strains from presumed nonhost P. syringae pathovars are able to grow and cause pathovar-unique disease symptoms in tomato leaves lacking Pto or Prf, although they did not reach the population levels or cause symptoms as severe as a control P. syringae pv. tomato strain. Seven of these strains were found to express avrPto or avrPtoB. The AvrPto- and AvrPtoB-expressing strains elicited disease resistance on tomato leaves expressing Pto and Prf. Thus, a gene-for-gene recognition event may contribute to host range restriction of many P. syringae pathovars on tomato species. Furthermore, we conclude that the diverse disease symptoms caused by

  12. A Chemical Kinetic Model of PRF Oxidation for HCCI Engine Ⅱ: Structure of a skeletal model%适用于HCCI发动机的基础燃料化学动力学模型Ⅱ:构造骨架机理

    Institute of Scientific and Technical Information of China (English)

    张庆峰; 郑朝蕾; 何祖威; 王迎

    2011-01-01

    提出了一个适用于HCCI发动机燃烧过程研究的基础燃料骨架机理模型,包含42种物质和71个反应.骨架机理分别对不同基础燃料(PRF0、PRF60、PRF80、PRF90和PRF100)在温度为667~1 350 K下进行了着火延迟期的预测计算,与试验结果的对比是较为吻合的.HCCI发动机试验的验证表明,无论是配比的基础燃料(PRF70、PRF91.8),还是单组分燃料(PRF100),该机理对缸内燃烧及排放情况的预测均是令人满意的.由此可知,该骨架机理在HCCI燃烧方面的预测性能是可靠的,可以应用于HCCI发动机的多维模拟.敏感性分析表明,针对PRF70与PRF91.8燃料HCCI工况下的燃烧情况,异辛烷与氧气的脱氢反应和正庚烷与羟基的氧化反应对缸内着火的影响较大,CH2O、CH3是非常重要的中间自由基.%A skeletal chemical kinetic mechanism including 42 species and 71 reactions for the oxidation of primary reference fuels (PRF) was proposed and applied to simulate homogeneous charge compression ignition (HCCI) combustion. The ignition delay predicted by the skeletal mechanism was validated with experiments. Validated results show good agreements for the PRF0, PRF60, PRF80, PRF90, PRF100 fuels over temperatures in the range of 667 K to 1 350 K. Validation of the present PRF mechanism was also performed with experiments from HCCI engines available in the literature, and good agreement was obtained for the PRF70, PRF91.8, PRF100 fuels. Results show that this PRF mechanism gives reliable performance for HCCI combustion predictions. The present PRF mechanism can be applied to multi-dimensional CFD simulations. Sensitivity analysis indicates that for PRF70 and PRF91.8 fuels under HCCI conditions, Hatom abstraction from iso-octane molecule reaction and OH addition to n-heptane molecule have large influence, and CH2O, CH3 are very important intermediate species.

  13. Repetitive transcranial magnetic stimulation for hallucination in schizophrenia spectrum disorders A meta-analysis***

    Institute of Scientific and Technical Information of China (English)

    Yingli Zhang; Wei Liang; Shichang Yang; Ping Dai; Lijuan Shen; Changhong Wang

    2013-01-01

    OBJECTIVE: This study assessed the efficacy and tolerability of repetitive transcranial magnetic stimulation for treatment of auditory hal ucination of patients with schizophrenia spectrum disorders. DATA SOURCES: Online literature retrieval was conducted using PubMed, ISI Web of Science, EMBASE, Medline and Cochrane Central Register of Control ed Trials databases from January 1985 to May 2012. Key words were “transcranial magnetic stimulation”, “TMS”, “repetitive transcranial magnetic stimulation”, and “hal ucination”. STUDY SELECTION: Selected studies were randomized control ed trials assessing therapeutic ef-ficacy of repetitive transcranial magnetic stimulation for hal ucination in patients with schizophrenia spectrum disorders. Experimental intervention was low-frequency repetitive transcranial magnetic stimulation in left temporoparietal cortex for treatment of auditory hal ucination in schizophrenia spectrum disorders. Control groups received sham stimulation. MAIN OUTCOME MEASURES: The primary outcome was total scores of Auditory Hal ucinations Rating Scale, Auditory Hal ucination Subscale of Psychotic Symptom Rating Scale, Positive and Negative Symptom Scale-Auditory Hal ucination item, and Hal ucination Change Scale. Secondary outcomes included response rate, global mental state, adverse effects and cognitive function. RESULTS: Seventeen studies addressing repetitive transcranial magnetic stimulation for treatment of schizophrenia spectrum disorders were screened, with controls receiving sham stimulation. Al data were completely effective, involving 398 patients. Overal mean weighted effect size for repeti-tive transcranial magnetic stimulation versus sham stimulation was statistical y significant (MD =-0.42, 95%CI: -0.64 to -0.20, P = 0.000 2). Patients receiving repetitive transcranial magnetic stimulation responded more frequently than sham stimulation (OR = 2.94, 95%CI: 1.39 to 6.24, P =0.005). No significant differences were found

  14. Hypersonic wave drag reduction performance of cylinders with repetitive laser energy depositions

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J; Hong, Y J; Li, Q; Huang, H, E-mail: fangjuan314@163.com [Academy of Equipment Command and Technology, Post Box 3380-86, Huairou Dis. Beijing 101416 (China)

    2011-02-01

    It has been widely research that wave drag reduction on hypersonic vehicle by laser energy depositions. Using laser energy to reduce wave drag can improve vehicle performance. A second order accurate scheme based on finite-difference method and domain decomposition of structural grid is used to compute the drag performance of cylinders in a hypersonic flow of Mach number 2 at altitude of 15km with repetitive energy depositions. The effects of frequency on drag reduction are studied. The calculated results show: the recirculation zone is generated due to the interaction between bow shock over the cylinder and blast wave produced by energy deposition, and a virtual spike which is supported by an axis-symmetric recirculation, is formed in front of the cylinder. By increasing the repetitive frequency, the drag is reduced and the oscillation of the drag is decreased; however, the energy efficiency decreases by increasing the frequency.

  15. Long-Term Cognitive and Neuropsychiatric Consequences of Repetitive Concussion and Head-Impact Exposure.

    Science.gov (United States)

    McAllister, Thomas; McCrea, Michael

    2017-03-01

    Initially, interest in sport-related concussion arose from the premise that the study of athletes engaged in sports associated with high rates of concussion could provide insight into the mechanisms, phenomenology, and recovery from mild traumatic brain injury. Over the last decade, concerns have focused on the possibility that, for some athletes, repetitive concussions may raise the long-term risk for cognitive decline, neurobehavioral changes, and neurodegenerative disease. First conceptualized as a discrete event with variable recovery trajectories, concussion is now viewed by some as a trigger of neurobiological events that may influence neurobehavioral function over the course of the life span. Furthermore, advances in technology now permit us to gain a detailed understanding of the frequency and intensity of repetitive head impacts associated with contact sports (eg, football, ice hockey). Helmet-based sensors can be used to characterize the kinematic features of concussive impacts, as well as the profiles of typical head-impact exposures experienced by athletes in routine sport participation. Many large-magnitude impacts are not associated with diagnosed concussions, whereas many diagnosed concussions are associated with more modest impacts. Therefore, a full understanding of this topic requires attention to not only the effects of repetitive concussions but also overall exposure to repetitive head impacts. This article is a review of the current state of the science on the long-term neurocognitive and neurobehavioral effects of repetitive concussion and head-impact exposure in contact sports.

  16. Repetition priming of words and nonwords in Alzheimer's disease and normal aging

    Science.gov (United States)

    Ober, Beth A.; Shenaut, Gregory K.

    2014-01-01

    Objective This study examines the magnitude and direction of nonword and word lexical decision repetition priming effects in Alzheimer’s disease (AD) and normal aging, focusing specifically on the negative priming effect sometimes observed with repeated nonwords. Method Probable Alzheimer's disease (AD) patients (30), elderly normal controls (34), and young normal controls (49) participated in a repetition priming experiment using low-frequency words and word-like nonwords with a letter-level orthographic orienting task at study followed by a lexical decision test phase. Results Although participants' reaction times were longer in AD compared to elderly normal, and elderly normal compared to young normal, the repetition priming effect and the degree to which the repetition priming effect was reversed for nonwords compared to words was unaffected by AD or normal aging. Conclusion AD patients, like young and elderly normal participants, are able to modify (in the case of words) and create (in the case of nonwords) long-term memory traces for lexical stimuli, based on a single orthographic processing trial. The nonword repetition results are discussed from the perspective of new vocabulary learning commencing with a provisional lexical memory trace created after orthographic encoding of a novel word-like letter string. PMID:25000325

  17. An educational approach to an epidemic of repetitive motion injuries among office workers

    Energy Technology Data Exchange (ETDEWEB)

    Halunen, L.J.

    1988-09-23

    Among office workers, repetitive motion injuries such as tendonitis, muscle fatigue, and nerve irritation (caused by poor posture and arm/hand positioning while performing repetitive tasks) are a fairly new phenomenon. Office workers and their managers are not prepared to respond properly to the identification and treatment of these injuries. We found an unusually high incidence within one department at a large research facility--the Lawrence Livermore National Laboratory--and developed an educational approach to reduce the frequency and severity of these injuries. Our approach was to inform the workers and managers about the origins and severity of repetitive motion injuries and their effect on the work force. Classes in ergonomic adjustment of video workstations were scheduled for all personnel who had jobs that required heavy keyboard use. The individual's responsibility in reporting any symptoms of repetitive motion injury was emphasized. We stressed to management the seriousness of the problem, the desirability of obtaining improved equipment workers may need, or the possibility of arranging a lighter workload for those showing symptoms of repetitive motion injuries. We followed these classes and briefings with additional videotaped material and written guidelines, pamphlets, and articles for further study and discussion. Early results indicate that informed workers in a supportive environment detect symptoms earlier, and therefore recover more quickly; managers who understand the problem and are able to respond positively gain better labor relations as well as lower injury rates. 4 refs., 2 figs.

  18. Ion cyclotron range of frequency mode conversion flow drive in D(He-3) plasmas on JET

    NARCIS (Netherlands)

    Lin, Y.; Mantica, P.; Hellsten, T.; Kiptily, V.; Lerche, E.; Nave, M. F. F.; Rice, J. E.; Van Eester, D.; de Vries, P. C.; Felton, R.; Giroud, C.; Tala, T.

    2012-01-01

    Ion cyclotron range of frequency (ICRF) mode conversion has been shown to drive toroidal flow in JET D(He-3) L-mode plasmas: B-t0 = 3.45 T, n(e0) similar to 3x10(19) m(-3), I-p = 2.8 and 1.8 MA, P-RF <= 3MW at 33MHz and -90 degrees phasing. Central toroidal rotation in the counter-I-p directi

  19. 不同频率重复经颅磁刺激对脑梗死患者上肢功能的影响%Effect of repetitive transcranial magnetic stimulation with different frequencies for upper limb function in patients with cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    沈滢; 单春雷; 殷稚飞; 孟殿怀; 侯红; 戴文骏; 励建安

    2012-01-01

    目的:比较不同频率的重复经颅磁刺激(rTMS)对脑梗死患者上肢功能的影响.方法:将30例患者随机分为0.5Hz组、1Hz组和2Hz组,常规药物治疗和康复训练基础上对健侧大脑皮质M1区进行不同频率(0.5Hz、1Hz、2Hz)的rTMS治疗,持续治疗20d,于治疗前、治疗第10天及第20天时对各组患者进行疗效评定,采用上肢Fugl-Meyer评分法、上肢运动力指数(MI)、偏瘫上肢功能测试(香港版)对患者上肢功能进行评定,同时检测各组患侧脑区运动诱发电位(MEP)皮质潜伏期及中枢运动传导时间(CMCT).结果:①上肢功能变化:治疗后3组上肢功能均明显提高,治疗10d时,0.5Hz组上肢MI评分明显高于2Hz组(P<0.05),1Hz组与其他两组组间差异无显著性意义(P>0.05);治疗20d时,0.5Hz组各项评分均优于2Hz组(P<0.05),1Hz组上肢MI评分优于2Hz组(P<0.05),0.5Hz组与1Hz组组间差异不具有显著性意义(P>0.05).②神经电生理学变化:治疗后3组MEP皮质潜伏期及CMCT均较治疗前明显缩短,治疗10d时,0.5Hz组CMCT明显短于2Hz组(P<0.05); 1Hz组与其他两组组间差异无显著性意义(P>0.05);治疗20d时,0.5Hz组MEP皮质潜伏期明显短于2Hz组(P<0.05),CMCT明显短于1Hz组和2Hz组(P<0.05); 1Hz组CMCT较2Hz组缩短明显(P<0.05).结论:0.5Hz或1Hz的重复经颅磁刺激作用于脑梗死患者健侧半球均可明显提高患侧脑区运动皮质的兴奋性,促进患侧上肢功能的恢复,且0.5Hz的刺激频率对提高患侧运动皮质的兴奋性最有效.%Objective:To compare the effect of repetitive transcranial magnetic stimulation (rTMS) with different frequencies for upper limb function in patients with cerebral infarction. Method: Thirty patients were randomly assigned to three groups receiving 0.5Hz, lHz, and 2Hz rTMS on M1 area of the unaffected hemisphere for 20d, respectively. In the same period, all patients were also treated with conventional medical treatment and

  20. Robust Repetitive Controller for Fast AFM Imaging

    CERN Document Server

    Necipoglu, Serkan; Has, Yunus; Guvenc, Levent; Basdogan, Cagatay

    2012-01-01

    Currently, Atomic Force Microscopy (AFM) is the most preferred Scanning Probe Microscopy (SPM) method due to its numerous advantages. However, increasing the scanning speed and reducing the interaction forces between the probe's tip and the sample surface are still the two main challenges in AFM. To meet these challenges, we take advantage of the fact that the lateral movements performed during an AFM scan is a repetitive motion and propose a Repetitive Controller (RC) for the z-axis movements of the piezo-scanner. The RC utilizes the profile of the previous scan line while scanning the current line to achieve a better scan performance. The results of the scanning experiments performed with our AFM set-up show that the proposed RC significantly outperforms a conventional PI controller that is typically used for the same task. The scan error and the average tapping forces are reduced by 66% and 58%, respectively when the scan speed is increased by 7-fold.

  1. A repetitive elements perspective in Polycomb epigenetics.

    Directory of Open Access Journals (Sweden)

    Valentina eCasa

    2012-10-01

    Full Text Available Repetitive elements comprise over two-thirds of the human genome. For a long time, these elements have received little attention since they were considered non functional. On the contrary, recent evidence indicates that they play central roles in genome integrity, gene expression and disease. Indeed, repeats display meiotic instability associated with disease and are located within common fragile sites, which are hotspots of chromosome rearrangements in tumors. Moreover, a variety of diseases have been associated with aberrant transcription of repetitive elements. Overall this indicates that appropriate regulation of repetitive elements’ activity is fundamental.Polycomb group (PcG proteins are epigenetic regulators that are essential for the normal development of multicellular organisms. Mammalian PcG proteins are involved in fundamental processes, such as cellular memory, cell proliferation, genomic imprinting, X-inactivation, and cancer development. PcG proteins can convey their activity through long-distance interactions also on different chromosomes. This indicates that the 3D organization of PcG proteins contributes significantly to their function. However, it is still unclear how these complex mechanisms are orchestrated and which role PcG proteins play in the multi-level organization of gene regulation. Intriguingly, the greatest proportion of Polycomb-mediated chromatin modifications is located in genomic repeats and it has been suggested that they could provide a binding platform for Polycomb proteins.Here, these lines of evidence are woven together to discuss how repetitive elements could contribute to chromatin organization in the 3D nuclear space.

  2. Emotional arousal enhances word repetition priming

    OpenAIRE

    Thomas, Laura A.; LaBar, Kevin S.

    2005-01-01

    Three experiments were conducted to determine if emotional content increases repetition priming magnitude. In the study phase of Experiment 1, participants rated high-arousing negative (taboo) words and neutral words for concreteness. In the test phase, they made lexical decision judgements for the studied words intermixed with novel words (half taboo, half neutral) and pseudowords. In Experiment 2, low-arousing negative (LAN) words were substituted for the taboo words, and in Experiment 3 al...

  3. The Rhythms of Echo. Variations on Repetition

    Directory of Open Access Journals (Sweden)

    Rosa María Aradra Sánchez

    2015-04-01

    Full Text Available This paper presents a study on the echo as metric and rhetorical procedure. It makes a brief tour through some of the poetic manifestations of echo in the Spanish literary tradition, and a brief tour through the attention that metric theory has paid to this phenomenon. Then it stops at the possibilities that rhetoric offers for its analysis from the generic approach of the discursive repetition phenomena.

  4. Factors Associated with Choking During Meals; a Risk Indicator for Repetitive Fevers in The Elderly Community

    Directory of Open Access Journals (Sweden)

    Takeshi Nishiyama

    2017-04-01

    Full Text Available Background: Choking during meals is a common symptom in the elderly, however the factors associated with it have not been fully clarified. In this study, we examined the factors associated with choking during meals. Methods: The oral health status and practices that promote oral health conditions was surveyed in 1305 community dwelling elderly using a self-administered questionnaire. Eight items including satisfaction with their oral condition, denture fit, chewing ability, tooth brushing frequency, dental visits, exercises to train muscles for chewing and swallowing, choking during meals, and repetitive fever were selected for analysis. Results: 25.1% of the subjects experienced choking during meals, which was significantly associated with repetitive fever occurrence. Differences in satisfaction levels with their oral condition, denture fit, chewing ability, and tooth brushing frequency were observed between groups with and without choking. Age, satisfaction level, and chewing ability were significantly associated with choking during meals. Conclusions: This study demonstrated that choking during meals is a risk indicator for repetitive fever in the elderly living in community settings. Poor chewing ability and dissatisfaction with their oral condition were risk factors associated with choking. These results suggest that training the elderly to eat efficiently and safely and improving oral conditions is necessary for those who suffer from choking during meals to prevent repetitive fever.

  5. Repetitive behaviour in autism: Imaging pathways and trajectories

    NARCIS (Netherlands)

    Langen, M.J.G.

    2009-01-01

    Repetitive behaviour in autism: Imaging pathways and trajectories Repetitive and rigid behaviour is one of the core symptoms of autism, a severe and lifelong child psychiatric disorder. Although repetitive behaviour symptoms often form a significant impairment for affected individuals, systematic st

  6. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    Science.gov (United States)

    2014-12-01

    Restrictive Repetitive Behaviors in Autism Spectrum Disorder . Authors: T.Q.Nguyen, B...Manoach. Functional Connectivity of the Dorsal Anterior Cingulate Cortex Predicts Restrictive Repetitive Behaviors in Autism Spectrum Disorder We...Introduction: Although restricted , repetitive behaviors (RRBs) are a highly disabling core feature of Autism Spectrum Disorders (ASDs), they

  7. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

    Science.gov (United States)

    Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

    2012-01-01

    Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

  8. Repetitive Elements in Mycoplasma hyopneumoniae Transcriptional Regulation

    Science.gov (United States)

    Cattani, Amanda Malvessi; Siqueira, Franciele Maboni; Guedes, Rafael Lucas Muniz; Schrank, Irene Silveira

    2016-01-01

    Transcriptional regulation, a multiple-step process, is still poorly understood in the important pig pathogen Mycoplasma hyopneumoniae. Basic motifs like promoters and terminators have already been described, but no other cis-regulatory elements have been found. DNA repeat sequences have been shown to be an interesting potential source of cis-regulatory elements. In this work, a genome-wide search for tandem and palindromic repetitive elements was performed in the intergenic regions of all coding sequences from M. hyopneumoniae strain 7448. Computational analysis demonstrated the presence of 144 tandem repeats and 1,171 palindromic elements. The DNA repeat sequences were distributed within the 5’ upstream regions of 86% of transcriptional units of M. hyopneumoniae strain 7448. Comparative analysis between distinct repetitive sequences found in related mycoplasma genomes demonstrated different percentages of conservation among pathogenic and nonpathogenic strains. qPCR assays revealed differential expression among genes showing variable numbers of repetitive elements. In addition, repeats found in 206 genes already described to be differentially regulated under different culture conditions of M. hyopneumoniae strain 232 showed almost 80% conservation in relation to M. hyopneumoniae strain 7448 repeats. Altogether, these findings suggest a potential regulatory role of tandem and palindromic DNA repeats in the M. hyopneumoniae transcriptional profile. PMID:28005945

  9. Modeling repetitive motions using structured light.

    Science.gov (United States)

    Xu, Yi; Aliaga, Daniel G

    2010-01-01

    Obtaining models of dynamic 3D objects is an important part of content generation for computer graphics. Numerous methods have been extended from static scenarios to model dynamic scenes. If the states or poses of the dynamic object repeat often during a sequence (but not necessarily periodically), we call such a repetitive motion. There are many objects, such as toys, machines, and humans, undergoing repetitive motions. Our key observation is that when a motion-state repeats, we can sample the scene under the same motion state again but using a different set of parameters; thus, providing more information of each motion state. This enables robustly acquiring dense 3D information difficult for objects with repetitive motions using only simple hardware. After the motion sequence, we group temporally disjoint observations of the same motion state together and produce a smooth space-time reconstruction of the scene. Effectively, the dynamic scene modeling problem is converted to a series of static scene reconstructions, which are easier to tackle. The varying sampling parameters can be, for example, structured-light patterns, illumination directions, and viewpoints resulting in different modeling techniques. Based on this observation, we present an image-based motion-state framework and demonstrate our paradigm using either a synchronized or an unsynchronized structured-light acquisition method.

  10. Repetitive element hypermethylation in multiple sclerosis patients.

    Science.gov (United States)

    Neven, K Y; Piola, M; Angelici, L; Cortini, F; Fenoglio, C; Galimberti, D; Pesatori, A C; Scarpini, E; Bollati, V

    2016-06-18

    Multiple sclerosis (MS) is a complex disorder of the central nervous system whose cause is currently unknown. Evidence is increasing that DNA methylation alterations could be involved in inflammatory and neurodegenerative diseases and could contribute to MS pathogenesis. Repetitive elements Alu, LINE-1 and SAT-α, are widely known as estimators of global DNA methylation. We investigated Alu, LINE-1 and SAT-α methylation levels to evaluate their difference in a case-control setup and their role as a marker of disability. We obtained blood samples from 51 MS patients and 137 healthy volunteers matched by gender, age and smoking. Methylation was assessed using bisulfite-PCR-pyrosequencing. For all participants, medical history, physical and neurological examinations and screening laboratory tests were collected. All repetitive elements were hypermethylated in MS patients compared to healthy controls. A lower Expanded Disability Status Scale (EDSS) score was associated with a lower levels of LINE-1 methylation for 'EDSS = 1.0' and '1.5 ≤ EDSS ≤ 2.5' compared to an EDSS higher than 3, while Alu was associated with a higher level of methylation in these groups: 'EDSS = 1.0' and '1.5 ≤ EDSS ≤ 2.5'. MS patients exhibit an hypermethylation in repetitive elements compared to healthy controls. Alu and LINE-1 were associated with degree of EDSS score. Forthcoming studies focusing on epigenetics and the multifactorial pathogenetic mechanism of MS could elucidate these links further.

  11. FRB repetition and non-Poissonian statistics

    CERN Document Server

    Connor, Liam; Oppermann, Niels

    2016-01-01

    We discuss some of the claims that have been made regarding the statistics of fast radio bursts (FRBs). In an earlier paper \\citep{2015arXiv150505535C} we conjectured that flicker noise associated with FRB repetition could show up in non-cataclysmic neutron star emission models, like supergiant pulses. We show how the current limits of repetition would be significantly weakened if their repeat rate really were non-Poissonian and had a pink or red spectrum. Repetition and its statistics have implications for observing strategy, generally favouring shallow wide-field surveys, since in the non-repeating scenario survey depth is unimportant. We also discuss the statistics of the apparent latitudinal dependence of FRBs, and offer a simple method for calculating the significance of this effect. We provide a generalized Bayesian framework for addressing this problem, which allows for direct model comparison. It is shown how the evidence for a steep latitudinal gradient of the FRB rate is less strong than initially s...

  12. Characterization of specific alleles in InlA and PrfA of Listeria monocytogenes isolated from foods in Osaka, Japan and their ability to invade Caco-2 cells.

    Science.gov (United States)

    Kanki, Masashi; Naruse, Hisayo; Taguchi, Masumi; Kumeda, Yuko

    2015-10-15

    Listeria monocytogenes expresses the surface protein internalin A (InlA), enabling the invasion of human intestinal epithelial cells to cause severe food-borne diseases. Full-length sequence analysis of inlA of 114 food isolates resulted in the detection of 29 isolates with a premature stop codon (PMSC) mutation and 6 isolates with 3-codon deletion mutations (aa 738 to 740) in inlA. The isolates with inlA PMSCs demonstrated a significantly lower level of invasion than the other food isolates in a Caco-2 cell invasion assay (P0.05). According to analysis of the positive regulatory factor A (PrfA) sequences of 114 L. monocytogenes isolates, 7 isolates of serotype 1/2a from chicken samples contained a PrfA protein with a 5-nucleotide deletion from 712 to 716, including a stop codon. Although the isolates with a 5-nucleotide deletion in prfA demonstrated invasion comparable to the isolates with non-truncated InlA and PrfA after growth at 30 °C (P>0.05), they exhibited a significantly higher level of invasion than the other isolates after growth at 20 °C (Pmonocytogenes isolates with the stop-codon deletion of PrfA. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Sampling strategies for subsampled segmented EPI PRF thermometry in MR guided high intensity focused ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Odéen, Henrik, E-mail: h.odeen@gmail.com; Diakite, Mahamadou [Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84108 and Department of Radiology, University of Utah, Salt Lake City, Utah 84108 (United States); Todd, Nick; Minalga, Emilee; Payne, Allison; Parker, Dennis L. [Department of Radiology, University of Utah, Salt Lake City, Utah 84108 (United States)

    2014-09-15

    Purpose: To investigate k-space subsampling strategies to achieve fast, large field-of-view (FOV) temperature monitoring using segmented echo planar imaging (EPI) proton resonance frequency shift thermometry for MR guided high intensity focused ultrasound (MRgHIFU) applications. Methods: Five different k-space sampling approaches were investigated, varying sample spacing (equally vs nonequally spaced within the echo train), sampling density (variable sampling density in zero, one, and two dimensions), and utilizing sequential or centric sampling. Three of the schemes utilized sequential sampling with the sampling density varied in zero, one, and two dimensions, to investigate sampling the k-space center more frequently. Two of the schemes utilized centric sampling to acquire the k-space center with a longer echo time for improved phase measurements, and vary the sampling density in zero and two dimensions, respectively. Phantom experiments and a theoretical point spread function analysis were performed to investigate their performance. Variable density sampling in zero and two dimensions was also implemented in a non-EPI GRE pulse sequence for comparison. All subsampled data were reconstructed with a previously described temporally constrained reconstruction (TCR) algorithm. Results: The accuracy of each sampling strategy in measuring the temperature rise in the HIFU focal spot was measured in terms of the root-mean-square-error (RMSE) compared to fully sampled “truth.” For the schemes utilizing sequential sampling, the accuracy was found to improve with the dimensionality of the variable density sampling, giving values of 0.65 °C, 0.49 °C, and 0.35 °C for density variation in zero, one, and two dimensions, respectively. The schemes utilizing centric sampling were found to underestimate the temperature rise, with RMSE values of 1.05 °C and 1.31 °C, for variable density sampling in zero and two dimensions, respectively. Similar subsampling schemes

  14. Repetition-rate-selectable high-speed optical gating in a VO{sub 2} thin film based on gain modulation of optical amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Wook; Kim, Bong Jun; Choi, Sung Youl; Chae, Byung Gyu; Kim, Hyun Tak [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Lee, Yong Wook [Pukyong National University, Busan (Korea, Republic of); Seo, Gi Wan [University of Science and Technology, Daejeon (Korea, Republic of); Lee, Yong Wan [University of Minnesota, Minneapolis, MN (United States)

    2010-12-15

    In this research, we investigated the dependence of the saturation-induced gain modulation (SIGM) on the modulation frequency of the input signal in an erbium-doped fiber amplifier (EDFA). By finding and incorporating the modulation frequency invariance of the SIGM realizable within some frequency range, we demonstrated a repetition-rate-selectable high-speed optical gating in two-terminal electrical devices based on vanadium-dioxide thin films. In the implemented optical gating system, the repetition rate could be freely chosen as an arbitrary frequency between 0.27 and 10 kHz without any degradation of the gating speed and the signal-to-noise ratio.

  15. IPC Position Paper Transitioning from MIL-P-50884C and MIL-PRF-31032 to IPC-6013 and Amendment 1

    CERN Document Server

    IPC - Association Connecting Electronics Industries. Northbrook, IL

    2000-01-01

    Developed and approved for distribution by the IPC Flexible Circuits Committee, this position paper serves as a guide for manufacturers and OEMs in transitioning from MIL-P-50884C and MIL-PRF-31032 to IPC-6013 and Amendment 1. The position paper offers a history of military specifications, from their overall development to the initiation of the Perry Initiative and Acquisition Reform. Also included in this document is a guide for implementing a Single Process Initiative (SPI), made available by the Department of the Navy (DoN)

  16. On the effect of injection timing on the ignition of lean PRF/air/EGR mixtures under direct dual fuel stratification conditions

    KAUST Repository

    Luong, Minh Bau

    2017-06-10

    The ignition characteristics of lean primary reference fuel (PRF)/air/exhaust gas recirculation (EGR) mixture under reactivity-controlled compression ignition (RCCI) and direct duel fuel stratification (DDFS) conditions are investigated by 2-D direct numerical simulations (DNSs) with a 116-species reduced chemistry of the PRF oxidation. The 2-D DNSs of the DDFS combustion are performed by varying the injection timing of iso-octane (i-C8H18) with a pseudo-iso-octane (PC8H18) model together with a novel compression heating model to account for the compression heating and expansion cooling effects of the piston motion in an engine cylinder. The PC8H18 model is newly developed to mimic the timing, duration, and cooling effects of the direct injection of i-C8H18 onto a premixed background charge of PRF/air/EGR mixture with composition inhomogeneities. It is found that the RCCI combustion exhibits a very high peak heat release rate (HRR) with a short combustion duration due to the predominance of the spontaneous ignition mode of combustion. However, the DDFS combustion has much lower peak HRR and longer combustion duration regardless of the fuel injection timing compared to those of the RCCI combustion, which is primarily attributed to the sequential injection of i-C8H18. It is also found that the ignition delay of the DDFS combustion features a non-monotonic behavior with increasing fuel-injection timing due to the different effect of fuel evaporation on the low-, intermediate-, and high-temperature chemistry of the PRF oxidation. The budget and Damköhler number analyses verify that although a mixed combustion mode of deflagration and spontaneous ignition exists during the early phase of the DDFS combustion, the spontaneous ignition becomes predominant during the main combustion, and hence, the spread-out of heat release rate in the DDFS combustion is mainly governed by the direct injection process of i-C8H18. Finally, a misfire is observed for the DDFS combustion when

  17. Regulation of PrfA-dependent Virulence Genes Expression in Listeria monocytogenes%单核细胞增生李斯特菌PrfA蛋白转录调控毒力基因表达的分子机制

    Institute of Scientific and Technical Information of China (English)

    罗勤; 张晓莉; 李兵; 冯爱平; 钱跃

    2008-01-01

    单核细胞增生李斯特菌(Listeria monocytogenes LM)属于典型的细胞内寄生革兰氏阳性菌,是WHO公布的四大食源性致病菌之一.LM不仅是人畜共患传染病李斯特菌病(listeriosis)的主要病原菌,也是研究胞内感染和细胞介导的免疫应答的模式细菌.绝大多数LM毒力基因的转录表达受到PrfA蛋白的调控.本文简单介绍了LM侵染宿主细胞必需的毒力基因及其产物;重点对毒力基因调节蛋白PrfA的结构和功能,PrfA调节毒力基因表达的主要方式最新进展进行了综述和讨论.

  18. Assessment of thermal effects of interstitial laser phototherapy on mammary tumors using proton resonance frequency method

    Science.gov (United States)

    Le, Kelvin; Li, Xiaosong; Figueroa, Daniel; Towner, Rheal A.; Garteiser, Philippe; Saunders, Debra; Smith, Nataliya; Liu, Hong; Hode, Tomas; Nordquist, Robert E.; Chen, Wei R.

    2011-12-01

    Laser immunotherapy (LIT) uses a synergistic approach to treat cancer systemically through local laser irradiation and immunological stimulation. Currently, LIT utilizes dye-assisted noninvasive laser irradiation to achieve selective photothermal interaction. However, LIT faces difficulties treating deeper tumors or tumors with heavily pigmented overlying skin. To circumvent these barriers, we use interstitial laser irradiation to induce the desired photothermal effects. The purpose of this study is to analyze the thermal effects of interstitial irradiation using proton resonance frequency (PRF). An 805-nm near-infrared laser with an interstitial cylindrical diffuser was used to treat rat mammary tumors. Different power settings (1.0, 1.25, and 1.5 W) were applied with an irradiation duration of 10 min. The temperature distributions of the treated tumors were measured by a 7 T magnetic resonance imager using PRF. We found that temperature distributions in tissue depended on both laser power and time settings, and that variance in tissue composition has a major influence in temperature elevation. The temperature elevations measured during interstitial laser irradiation by PRF and thermocouple were consistent, with some variations due to tissue composition and the positioning of the thermocouple's needle probes. Our results indicated that, for a tissue irradiation of 10 min, the elevation of rat tumor temperature ranged from 8 to 11°C for 1 W and 8 to 15°C for 1.5 W. This is the first time a 7 T magnetic resonance imager has been used to monitor interstitial laser irradiation via PRF. Our work provides a basic understanding of the photothermal interaction needed to control the thermal damage inside a tumor using interstitial laser treatment. Our work may lead to an optimal protocol for future cancer treatment using interstitial phototherapy in conjunction with immunotherapy.

  19. High repetition rate passively Q-switched fiber and microchip lasers for optical resolution photoacoustic imaging

    Science.gov (United States)

    Shi, Wei; Utkin, Ilya; Ranasinghesagara, Janaka; Pan, Lei; Godwal, Yogesh; Kerr, Shaun; Zemp, Roger J.; Fedosejevs, Robert

    2010-02-01

    Optical-resolution photoacoustic microscopy is a novel imaging technology for visualizing optically-absorbing superficial structures in vivo with lateral spatial resolution determined by optical focusing rather than acoustic detection. Since scanning of the illumination spot is required, the imaging speed is limited by the scanning speed and the laser pulse repetition rate. Unfortunately, lasers with high-repetition rate and suitable pulse durations and energies are difficult to find. We are developing compact laser sources for this application. Passively Q-switched fiber and microchip lasers with pulse repetition rates up to 300 kHz are demonstrated. Using a diode-pumped microchip laser fiber-coupled to a large mode-area Yb-doped fiber amplifier we obtained 60μJ 1-ns pulses at the frequency-doubled 532-nm wavelength. The pulse-repetition rate was determined by the power of the microchip laser pump source at 808nm and may exceed 10 kHz. Additionally, a passively Q-switched fiber laser utilizing a Yb-doped double-cladding fiber and an external saturable absorber has shown to produce 250ns pulses at repetition rates of 100-300 KHz. A photoacoustic probe enabling flexible scanning of the focused output of these lasers consisted of a 45-degree glass prism in an optical index-matching fluid. Photoacoustic signals exiting the sample are deflected by the prism to an ultrasound transducer. Phantom studies with a 7.5-micron carbon fiber demonstrate the ability to image with optical rather than acoustic resolution. We believe that the high pulse-repetition rates and the potentially compact and fiber-coupled nature of these lasers will prove important for clinical imaging applications where realtime imaging performance is essential.

  20. REPETITION AS A SPECIAL TYPE OF SYNTACTIC RELATIONS IN REPRESENTED SPEECH: BASED ON THE PROSE BY MARINA TSVETAEVA

    Directory of Open Access Journals (Sweden)

    Olga Pavlovna Puchinina

    2017-03-01

    Full Text Available The author studies the peculiarities of repetition, being one of the ways to build syntactic relations in the represented speech structure, based on the prose by Marina Tsvetaeva. The article describes the different types of repetitions, their distinctive features and frequency of usage in the studied tests. The author describes different types of repetitions in the studied cases of represented speech from the point of view of their position. Repetition occurs at the beginning, end of sentences, beginning and end of a statement or paragraph, end of a statement and beginning of the next one; lexical items may be repeated in the middle of a statement. The morphology of repetitions, i.e., the way by what parts of speech the repeated words and structures are expressed, is of interest from the point of view of functional grammar. The author notes that Tsvetaeva repeats different parts of speech: conjunctions, prepositions, particles, nouns, pronouns, adverbs, numerals, verbs, modal words or a combination of two words. Moreover, due to her special intention, Tsvetaeva intensifies repetition through particular phonetic devices, such as alliteration, rhyme and rhythm, which make her prosaic works sound poetic. Purpose. The article is devoted to the topic of rendering another person’s speech, as it continues to be one of the most important issues of modern linguistics. The subject of analysis is repetition and its different types in the structure of represented speech on the material of prose texts by Marina Tsvetaeva. The author’s aims is to reveal the way these types of repetition (lexical, syntactic, semantic ones function in the structure of represented speech and what effect is achieved with their help. Methodology. The research has been conducted using the continuous sampling method and the quantitative estimation method, aimed to identify the frequency of using different types of repetition and repeated parts of speech and constructions in the

  1. Generation of picosecond laser pulses at 1030 nm with gigahertz range continuously tunable repetition rate.

    Science.gov (United States)

    Aubourg, Adrien; Lhermite, Jérôme; Hocquet, Steve; Cormier, Eric; Santarelli, Giorgio

    2015-12-01

    We report on a watt range laser system generating picosecond pulses using electro-optical modulation of a 1030 nm single frequency low noise laser diode. Its repetition rate is continuously tunable between 11 and 18 GHz. Over this range, output spectra and pulse characteristics are measured and compared with a numerical simulation. Finally, amplitude and residual phase noise measurements of the source are also presented.

  2. The Effect of 10 Hz Repetitive Transcranial Magnetic Stimulation of Posterior Parietal Cortex on Visual Attention

    OpenAIRE

    Isabel Dombrowe; Georgiana Juravle; Mohsen Alavash; Carsten Gießing; Claus C Hilgetag

    2015-01-01

    Repetitive transcranial magnetic stimulation (rTMS) of the posterior parietal cortex (PPC) at frequencies lower than 5 Hz transiently inhibits the stimulated area. In healthy participants, such a protocol can induce a transient attentional bias to the visual hemifield ipsilateral to the stimulated hemisphere. This bias might be due to a relatively less active stimulated hemisphere and a relatively more active unstimulated hemisphere. In a previous study, Jin and Hilgetag (2008) tried to switc...

  3. Storytelling and Repetitive Narratives for Design Empathy

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Judice, Andrea; Soini, Katja

    2007-01-01

    Today it is widely established in design research that empathy is an important part of creating a true understanding of user experience as a resource for design. A typical challenge is how to transmit the feeling of empathy acquired by user studies to designers who have not participated in the user...... study. In this paper, we show how we attained an empathic understanding through storytelling and aroused empathy to others using repetitive narratives in an experimental presentation bringing forth factual, reflective and experiential aspects of the user information. Taking as a starting point our...... experiences with the design project Suomenlinna Seclusive, we conclude with the potential of using narratives for invoking design empathy....

  4. A miniature high repetition rate shock tube.

    Science.gov (United States)

    Tranter, R S; Lynch, P T

    2013-09-01

    A miniature high repetition rate shock tube with excellent reproducibility has been constructed to facilitate high temperature, high pressure, gas phase experiments at facilities such as synchrotron light sources where space is limited and many experiments need to be averaged to obtain adequate signal levels. The shock tube is designed to generate reaction conditions of T > 600 K, P shock waves with predictable characteristics are created, repeatably. Two synchrotron-based experiments using this apparatus are also briefly described here, demonstrating the potential of the shock tube for research at synchrotron light sources.

  5. Storytelling and Repetitive Narratives for Design Empathy

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Judice, Andrea; Soini, Katja

    2007-01-01

    Today it is widely established in design research that empathy is an important part of creating a true understanding of user experience as a resource for design. A typical challenge is how to transmit the feeling of empathy acquired by user studies to designers who have not participated in the user...... study. In this paper, we show how we attained an empathic understanding through storytelling and aroused empathy to others using repetitive narratives in an experimental presentation bringing forth factual, reflective and experiential aspects of the user information. Taking as a starting point our...... experiences with the design project Suomenlinna Seclusive, we conclude with the potential of using narratives for invoking design empathy....

  6. The repetitive component of the sunflower genome

    Directory of Open Access Journals (Sweden)

    T. Giordani

    2014-08-01

    Full Text Available The sunflower (Helianthus annuus and species belonging to the genus Helianthus are emerging as a model species and genus for a number of studies on genome evolution. In this review, we report on the repetitive component of the H. annuus genome at the biochemical, molecular, cytological, and genomic levels. Recent work on sunflower genome composition is described, with emphasis on different types of repeat sequences, especially LTR-retrotransposons, of which we report on isolation, characterisation, cytological localisation, transcription, dynamics of proliferation, and comparative analyses within the genus Helianthus.

  7. Radio frequency ablation in drug resistant chemotherapy-induced peripheral neuropathy: A case report and review of literature

    Directory of Open Access Journals (Sweden)

    Naveen Yadav

    2010-01-01

    Full Text Available Chemotherapy-induced peripheral neuropathy (CIPN is a frequently encountered complication. It can result from a host of agents. Various modalities of treatment have been advocated, of which a novel method is radio frequency ablation. A 63-year-old male, a case of carcinoma prostrate with bone metastases, presented with tingling and numbness in right upper limb. He was given morphine, gabapentin and later switched to pregabalin, but medications provided only minor relief. Initially he was given stellate ganglion block, then radiofrequency ablation of dorsal root ganglion was done, but it failed to provide complete relief. Pulsed radiofrequency ablation (PRF was then done for 90 seconds; two cycles each in both ulnar and median nerve. After the procedure the patient showed improvement in symptoms within four to five hours and 80% relief in symptoms. We conclude that PRF can be used for the treatment of drug resistant CIPN.

  8. In-vitro release pharmacokinetics of amikacin, teicoplanin and polyhexanide in a platelet rich fibrin—layer (PRF)—a laboratory evaluation of a modern, autologous wound treatment

    Science.gov (United States)

    Thalhammer, Florian

    2017-01-01

    Objectives Platelet rich fibrin (PRF) is an autologous fibrin glue, produced from patients' blood, which, besides intraoperative use, has applications in the treatment of infected wounds. The combination with antimicrobial agents results in a prolonged antibacterial effect allowing for wound dressing change intervals of seven days even in infected wounds. The aim of this study was to evaluate release kinetics of amikacin, teicoplanin or polyhexanide from a PRF-layer. Methods PRF mixed with teicoplanin, amikacin or polyhexanide was sprayed on a silicon gauze patch and put on a colombia agar with bacteria with known minimal inhibitory concentration (MIC) and incubated for 24 hours and afterwards transferred to another agar with the same bacterial strain. Inhibition zones were measured every 24 hours. This was repeated on 7 consecutive days. Antibiotic concentrations were calculated by interpolation. Results More than 1000 mg/L teicoplanin were released within the first 24 hours and 28.22 mg/L after 168 hours. Amikacin release was above 10,000 mg/L within the first 24 hours and still 120.8 mg/L after 120 hours. A release of polyhexanide could be verified for the first 24 hours only. Consequently teicoplanin and amikacin released from PRF showed antimicrobial in-vitro effects for almost a week, whereas an antimicrobial effect of polyhexanide could only be verified for the first 24 hours. Conclusions Our Results show that a weekly dressing regimen may be justified in wounds treated with PRF plus amikacin or teicoplanin, since bacteria will be eradicated over a considerable period of time after a single application of PRF. PMID:28686663

  9. Increased vascularization during early healing after biologic augmentation in repair of chronic rotator cuff tears using autologous leukocyte- and platelet-rich fibrin (L-PRF): a prospective randomized controlled pilot trial.

    Science.gov (United States)

    Zumstein, Matthias A; Rumian, Adam; Lesbats, Virginie; Schaer, Michael; Boileau, Pascal

    2014-01-01

    We hypothesized that arthroscopic rotator cuff repairs using leukocyte- and platelet-rich fibrin (L-PRF) in a standardized, modified protocol is technically feasible and results in a higher vascularization response and watertight healing rate during early healing. Twenty patients with chronic rotator cuff tears were randomly assigned to 2 treatment groups. In the test group (N = 10), L-PRF was added in between the tendon and the bone during arthroscopic rotator cuff repair. The second group served as control (N = 10). They received the same arthroscopic treatment without the use of L-PRF. We used a double-row tension band technique. Clinical examinations including subjective shoulder value, visual analog scale, Constant, and Simple Shoulder Test scores and measurement of the vascularization with power Doppler ultrasonography were made at 6 and 12 weeks. There have been no postoperative complications. At 6 and 12 weeks, there was no significant difference in the clinical scores between the test and the control groups. The mean vascularization index of the surgical tendon-to-bone insertions was always significantly higher in the L-PRF group than in the contralateral healthy shoulders at 6 and 12 weeks (P = .0001). Whereas the L-PRF group showed a higher vascularization compared with the control group at 6 weeks (P = .001), there was no difference after 12 weeks of follow-up (P = .889). Watertight healing was obtained in 89% of the repaired cuffs. Arthroscopic rotator cuff repair with the application of L-PRF is technically feasible and yields higher early vascularization. Increased vascularization may potentially predispose to an increased and earlier cellular response and an increased healing rate. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  10. Improved discrimination of visual stimuli following repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Michael L Waterston

    Full Text Available BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary to expectations of a visual deficit, we find that rTMS often improves the discrimination of visual features. For coarse orientation tasks, discrimination of a static stimulus improved consistently following theta-burst stimulation of the occipital lobe. Using a reaction-time task, we found that these improvements occurred throughout the visual field and lasted beyond one hour post-rTMS. Low-frequency (1 Hz stimulation yielded similar improvements. In contrast, we did not find consistent effects of rTMS on performance in a fine orientation discrimination task. CONCLUSIONS/SIGNIFICANCE: Overall our results suggest that rTMS generally improves or has no effect on visual acuity, with the nature of the effect depending on the type of stimulation and the task. We interpret our results in the context of an ideal-observer model of visual perception.

  11. 压力对骨髓间充质干细胞(BMSCs)膜片复合富血小板纤维蛋白(PRF)双膜结构中BMSCs成软骨能力的影响%Effects of pressure on chondrogenic differentiation capacity of BMSCs in BMSCs/PRF compound membranes

    Institute of Scientific and Technical Information of China (English)

    陈慧; 李轶杰; 程百祥; 杜静; 张旻; 陈永进

    2013-01-01

    ABM; To investigate the effects of pressure on the chondrogenic differentiation of bone marrow mesenchymal stem cells ( BMSCs) in the double membrane of BMSCs combined with platelet - rich fibrin (PRF) (BMSCs/PRF). METHODS: BMSCs were obtained from New Zealand rabbits by density gradient centrifugation, identified by flowcytometry and osteogenic and adipogenic induction experiments. Then BMSCs sheet was prepared. PRF membrane was obtained by centrifuging the auricle arterial whole blood and squeezing the PRF clot. BMSCs sheet was then co - cultured with PRF membrane for 2 days. Afterwards, the BMSCs/PRF compound membranes were stimulated by hydrostatic pressure at 0 kPa (control) ,90, 120 and 150 kPa for 1 and 6 h per day for 2, 4 and 6 days, respectively. Gene expression of PCNA, SOX-9, aggrecan and COL- II of the BMSCs in the BMSCs/PRF compound was examined by real-time PCR . RESULTS: The gene expression of PCNA was promoted by the pressure, especially at 120 kPa/1 h for 4 days. After 2 consecutive days of pressure treatment, aggrecan was statistically up-regulated, while the expression of SOX-9 and COL-II remained unchanged. However, all the three gene expressions were up -regulated after 4 consecutive days of the pressure treatment, particularly in the 120 kPa/lh group. After 6 consecutive days of pressure treatment, only COL-II gene expression under 90 kPa or 120 kPa for 1 h increased. CONCLUSION: Suitable Pressure stimulation may promote the proliferation and chondrogenic differentiation of BMSCs in the composite of BMSCs/PRF.%目的:观察压力对骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BMSCs)复合富血小板纤维蛋白(Platelet-rich Fibrin,PRF) (BMSCs/PRF)双膜结构中BMSCs的成软骨能力.方法:密度梯度离心法分离培养兔骨髓间充质干细胞,经表面标记分子检测及成骨、成脂能力鉴定后,制备细胞膜片.将取自同一个体的兔耳廓动脉全血通过离心获得PRF,将PRF压制成膜后与BMSCs

  12. [The use of platelet concentrates: platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) in bone reconstruction prior to dental implant surgery].

    Science.gov (United States)

    Baeyens, W; Glineur, R; Evrard, L

    2010-01-01

    The autologous platelet concentrates--Platelet-Rich Plasma (PRP) and Platelet-Rich Fibrin (PRF)--are used in various medical fields, particularly in oral and maxillofacial surgery. These concentrates contain high levels of growth factors, including the 3 isomers of PDGF (platelet-derived growth factor), 2 of the numerous transforming growth factors (TGF-beta), the insulinlike growth factor (IGF), the epithelial growth factor (EGF) and the vascular endothelial growth factor (VEGF), which are the key elements in wound healing, particularly in bone regeneration. Platelet concentrates are easy to apply in clinical practice and offer potential benefits including rapid wound healing and bone regeneration, and can therefore be considered to be new therapeutic adjuvants. In dental implant surgery they are used in bone reconstruction prior or concomitant to implant procedures, and also for dental extraction socket preservation. Their use result in enhanced bone graft density and maturation. A literature review on the use of PRP/PRF in maxillofacial and dental implant surgery is proposed.

  13. A Systematic Investigation of Parameters Influencing Droplet Rain in the Listeria monocytogenes prfA Assay - Reduction of Ambiguous Results in ddPCR

    Science.gov (United States)

    Witte, Anna Kristina; Mester, Patrick; Fister, Susanne; Witte, Matthias; Schoder, Dagmar; Rossmanith, Peter

    2016-01-01

    The droplet digital polymerase chain reaction (ddPCR) determines DNA amounts based upon the pattern of positive and negative droplets, according to Poisson distribution, without the use of external standards. However, division into positive and negative droplets is often not clear because a part of the droplets has intermediate fluorescence values, appearing as “rain” in the plot. Despite the droplet rain, absolute quantification with ddPCR is possible, as shown previously for the prfA assay in quantifying Listeria monocytogenes. Nevertheless, reducing the rain, and thus ambiguous results, promotes the accuracy and credibility of ddPCR. In this study, we extensively investigated chemical and physical parameters for optimizing the prfA assay for ddPCR. While differences in the concentration of all chemicals and the dye, quencher and supplier of the probe did not alter the droplet pattern, changes in the PCR cycling program, such as prolonged times and increased cycle numbers, improved the assay. PMID:27992475

  14. Influence of Leukocyte- and Platelet-Rich Fibrin (L-PRF in the Healing of Simple Postextraction Sockets: A Split-Mouth Study

    Directory of Open Access Journals (Sweden)

    Gaetano Marenzi

    2015-01-01

    Full Text Available The aim of this study was to evaluate the effects of leukocyte- and platelet-rich fibrin (L-PRF on the pain and soft tissue healing after tooth extractions. Twenty-six patients (9 males and 17 females were treated with multiple extractions (2 to 8, with a total of 108 extractions. This was an exploratory single blinded randomized clinical trial with a split-mouth design. The pain after the surgery was assessed in each patient by the VAS scale (1 to 10 at intervals of 24-48-72-96 hours. The soft tissue healing was clinically evaluated at 3, 7, 14, and 21 days after surgery by the same examiner surgeon, using the modified Healing Index (4 to 12. The mean value of postextraction pain was 3.2 ± 0.3 in the experimental sides and 4.1 ± 0.1 in the control sides. After 7 days from the extractions, the values of modified Healing Index in the experimental and control groups were, respectively, 4.8 ± 0.6 and 5.1 ± 0.9. The use of L-PRF in postextraction sockets filling can be proposed as a useful procedure in order to manage the postoperative pain and to promote the soft tissue healing process, reducing the early adverse effects of the inflammation.

  15. Influence of Leukocyte- and Platelet-Rich Fibrin (L-PRF) in the Healing of Simple Postextraction Sockets: A Split-Mouth Study.

    Science.gov (United States)

    Marenzi, Gaetano; Riccitiello, Francesco; Tia, Mariano; di Lauro, Alessandro; Sammartino, Gilberto

    2015-01-01

    The aim of this study was to evaluate the effects of leukocyte- and platelet-rich fibrin (L-PRF) on the pain and soft tissue healing after tooth extractions. Twenty-six patients (9 males and 17 females) were treated with multiple extractions (2 to 8), with a total of 108 extractions. This was an exploratory single blinded randomized clinical trial with a split-mouth design. The pain after the surgery was assessed in each patient by the VAS scale (1 to 10) at intervals of 24-48-72-96 hours. The soft tissue healing was clinically evaluated at 3, 7, 14, and 21 days after surgery by the same examiner surgeon, using the modified Healing Index (4 to 12). The mean value of postextraction pain was 3.2 ± 0.3 in the experimental sides and 4.1 ± 0.1 in the control sides. After 7 days from the extractions, the values of modified Healing Index in the experimental and control groups were, respectively, 4.8 ± 0.6 and 5.1 ± 0.9. The use of L-PRF in postextraction sockets filling can be proposed as a useful procedure in order to manage the postoperative pain and to promote the soft tissue healing process, reducing the early adverse effects of the inflammation.

  16. Robustification and Optimization in Repetitive Control For Minimum Phase and Non-Minimum Phase Systems

    Science.gov (United States)

    Prasitmeeboon, Pitcha

    Repetitive control (RC) is a control method that specifically aims to converge to zero tracking error of a control systems that execute a periodic command or have periodic disturbances of known period. It uses the error of one period back to adjust the command in the present period. In theory, RC can completely eliminate periodic disturbance effects. RC has applications in many fields such as high-precision manufacturing in robotics, computer disk drives, and active vibration isolation in spacecraft. The first topic treated in this dissertation develops several simple RC design methods that are somewhat analogous to PID controller design in classical control. From the early days of digital control, emulation methods were developed based on a Forward Rule, a Backward Rule, Tustin's Formula, a modification using prewarping, and a pole-zero mapping method. These allowed one to convert a candidate controller design to discrete time in a simple way. We investigate to what extent they can be used to simplify RC design. A particular design is developed from modification of the pole-zero mapping rules, which is simple and sheds light on the robustness of repetitive control designs. RC convergence requires less than 90 degree model phase error at all frequencies up to Nyquist. A zero-phase cutoff filter is normally used to robustify to high frequency model error when this limit is exceeded. The result is stabilization at the expense of failure to cancel errors above the cutoff. The second topic investigates a series of methods to use data to make real time updates of the frequency response model, allowing one to increase or eliminate the frequency cutoff. These include the use of a moving window employing a recursive discrete Fourier transform (DFT), and use of a real time projection algorithm from adaptive control for each frequency. The results can be used directly to make repetitive control corrections that cancel each error frequency, or they can be used to update a

  17. Repetitive magnetic stimulation affects the microenvironment of nerve regeneration and evoked potentials after spinal cord injury.

    Science.gov (United States)

    Jiang, Jin-Lan; Guo, Xu-Dong; Zhang, Shu-Quan; Wang, Xin-Gang; Wu, Shi-Feng

    2016-05-01

    Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modified Allen's method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These findings confirm that repetitive magnetic stimulation of the spinal cord improved the microenvironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord.

  18. Repetitive magnetic stimulation affects the microenvironment of nerve regeneration and evoked potentials after spinal cord injury

    Directory of Open Access Journals (Sweden)

    Jin-lan Jiang

    2016-01-01

    Full Text Available Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modified Allen′s method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These findings confirm that repetitive magnetic stimulation of the spinal cord improved the microenvironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord.

  19. Efficacy of slow repetitive transcranial magnetic stimulation in the treatment of resistant auditory hallucinations in schizophrenia : A meta-analysis

    NARCIS (Netherlands)

    Aleman, Andre; Sommer, Iris E.; Kahn, Rene S.

    2007-01-01

    Objective: Slow repetitive transcranial magnetic stimulation (rTMS), at a frequency of 1 Hz, has been proposed as a treatment for auditory hallucinations. Several studies have now been reported regarding the efficacy of TMS treatment, but results were inconsistent. Therefore, meta-analytic integrati

  20. A Repetitive Control Scheme Aimed at Compensating the 6k + 1 Harmonics for a Three-Phase Hybrid Active Filter

    DEFF Research Database (Denmark)

    Luo, Zhaoxu; Su, Mei; Yang, Jian;

    2016-01-01

    The traditional repetitive controller has relatively worse stability and poor transient performance because it generates infinite gain at all the integer multiples of the fundamental frequency, and its control action is postponed by one fundamental period (T0). To improve these disadvantages, many...

  1. Frequency comb-based four-wave-mixing spectroscopy.

    Science.gov (United States)

    Lomsadze, Bachana; Cundiff, Steven T

    2017-06-15

    We experimentally demonstrate four-wave-mixing (FWM) spectroscopy using frequency combs. The experiment uses a geometry where excitation pulses and FWM signals generated by a sample co-propagate. We separate them in the radio frequency domain by heterodyne detection with a local oscillator comb that has a different repetition frequency.

  2. Arbitrary optical frequency synthesis traced to an optical frequency comb

    Science.gov (United States)

    Cai, Zihang; Zhang, Weipeng; Yang, Honglei; Li, Yan; Wei, Haoyun

    2016-11-01

    An arbitrary optical frequency synthesizer with a broad tuning range and high frequency accuracy is presented. The system includes an external cavity diode laser (ECDL) as the output laser, an Erbium-doped optical frequency comb being a frequency reference, and a control module. The optical frequency from the synthesizer can be continuously tuned by the large-scale trans-tooth switch and the fine intra-tooth adjustment. Robust feedback control by regulating the current and PZT voltage enables the ECDL to phase-lock to the Erbium-doped optical frequency comb, therefore to keep stable frequency output. In the meanwhile, the absolute frequency of the synthesizer is determined by the repetition rate, the offset frequency and the beat frequency. All the phase lock loops in the system are traced back to a Rubidium clock. A powerful and friendly software is developed to make the operation convenient by integrating the functions of frequency setting, tuning, tracing, locking and measuring into a LabVIEW interface. The output frequency tuning span and the uncertainty of the system are evaluated as >6 THz and Ring-Down Spectroscopy.

  3. The role of short-term memory impairment in nonword repetition, real word repetition, and nonword decoding: A case study.

    Science.gov (United States)

    Peter, Beate

    2017-09-21

    In a companion study, adults with dyslexia and adults with a probable history of childhood apraxia of speech showed evidence of difficulty with processing sequential information during nonword repetition, multisyllabic real word repetition and nonword decoding. Results suggested that some errors arose in visual encoding during nonword reading, all levels of processing but especially short-term memory storage/retrieval during nonword repetition, and motor planning and programming during complex real word repetition. To further investigate the role of short-term memory, a participant with short-term memory impairment (MI) was recruited. MI was confirmed with poor performance during a sentence repetition and three nonword repetition tasks, all of which have a high short-term memory load, whereas typical performance was observed during tests of reading, spelling, and static verbal knowledge, all with low short-term memory loads. Experimental results show error-free performance during multisyllabic real word repetition but high counts of sequence errors, especially migrations and assimilations, during nonword repetition, supporting short-term memory as a locus of sequential processing deficit during nonword repetition. Results are also consistent with the hypothesis that during complex real word repetition, short-term memory is bypassed as the word is recognized and retrieved from long-term memory prior to producing the word.

  4. A phonetic approach to consonant repetition in early words.

    Science.gov (United States)

    Kim, Namhee; Davis, Barbara L

    2015-08-01

    The goal of this study was to evaluate movement-based principles for understanding early speech output patterns. Consonant repetition patterns within children's actual productions of word forms were analyzed using spontaneous speech data from 10 typically developing American-English learning children between 12 and 36 months of age. Place of articulation, word level patterns, and developmental trends in CVC and CVCV repeated word forms were evaluated. Labial and coronal place repetitions dominated. Regressive repetition (e.g., [gag] for "dog") occurred frequently in CVC but not in CVCV word forms. Consonant repetition decreased over time. However, the children produced sound types available reported as being within young children's production system capabilities in consonant repetitions in all time periods. Findings suggest that a movement-based approach can provide a framework for comprehensively characterizing consonant place repetition patterns in early speech development.

  5. Repetition and Reactance in Graham’s "Underneath" Poems

    Directory of Open Access Journals (Sweden)

    Roghayeh Farsi

    2017-09-01

    Full Text Available The present paper gives a detailed analysis and interpretation of 16 poems in Jorie Graham's collection, Swarm (2000, which bear "UNDERNEATH" as their main titles. The poems are marked with different types of repetition such as graphological repetition, word, phrase, and sentential repetition, semantic repetition, and syntactic repetition. The study draws on Lakoff and Johnson's theories on metaphor and Brehm and Brehm’s reactance theory. It is argued "underneath" is a conceptual (orientational metaphor which signifies a state of being limited, lack of control and freedom, and loss of power. The paper investigates the speaker's reactant behavior in "Underneath" poems, seeking a way to restore her lost freedom. Reactance behaviors can be skepticism, inertia, aggression, and resistance. It is concluded despite her thematic inertia, representing her submission to the oppressed state, her stylistic reactance reflected in repetitions, innovations, and disruptive diction stands for her attempts to regain her lost control.

  6. 高频重复经颅磁刺激治疗精神分裂症难治性阴性症状的随机双盲对照试验%Effects of high frequency repetitive transcranial magnetic stimulation on refractory negative symptom of schizophrenia: A double blind, randomized controlled trial

    Institute of Scientific and Technical Information of China (English)

    任艳萍; 周东丰; 蔡焯基; 黄青; 卢芩; 陈琦

    2011-01-01

    目的:探讨双背侧前额叶高频重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)治疗精神分裂症难治性阴性症状的疗效和安全性,并观察不良反应.方法:本研究为双盲随机对照临床试验.研究对象来源于2002年11月1日至2003年12月31日期间就诊于北京大学第六医院和北京安定医院的门诊和住院患者,符合美国精神疾病诊断与统计手册第4版(Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition,DSM.IV)中精神分裂症诊断标准.23例以难治性阴性症状为主的精神分裂症患者随机分为rTMS治疗组(n=12)和对照组(n=11),分别给予10次20Hz rTMS真刺激和伪刺激治疗,治疗期间维持原有抗精神病药种类及剂量不变.采用阳性和阴性症状量表(Positive and Negative Syndrome Scale,PANSS)评估临床症状,采用治疗中需处理的不良反应症状量表(Treatment Emergent Symptom scale,TESS)及其他检查评估不良反应.结果:23例患者均完成治疗.治疗组有效率高于对照组(34%vs.17%,P<0.05).未观察到明显不良反应.结论:抗精神病药合并20 Hz双背侧前额叶重复经颅磁刺激治疗精神分裂症难治性阴性症状有效、安全.%Objective: To examine the therapeutic effects of dual dorsolateral prefrontal repetitive transcranial magnetic stimulation ( rTMS ) on refractory negative symptom experienced by patients with schizophrenia. Methods: A double-blind, randomized controlled study was conducted. Totally 23 schizophrenic patients met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for schizophrenia were recruited. Subjects were grouped into active treatment subgroup and sham subgroup randomly. Clinical symptom was measured with the Positive and Negative Symptom Scale (PANSS) . Side effects were valuated with the Treatment Emergent Symptom Scale (TESS). Results: Totally 23 subjects completed the trial. The treatment efficiency of

  7. FEMA Hazard Mitigation Assistance Repetitive Flood Claims (RFC) Data

    Data.gov (United States)

    Department of Homeland Security — This dataset contains closed and obligated projects funded under the following Hazard Mitigation Assistance (HMA) grant programs: Repetitive Flood Claims (RFC). The...

  8. A review of neuroimaging findings in repetitive brain trauma.

    Science.gov (United States)

    Koerte, Inga K; Lin, Alexander P; Willems, Anna; Muehlmann, Marc; Hufschmidt, Jakob; Coleman, Michael J; Green, Isobel; Liao, Huijun; Tate, David F; Wilde, Elisabeth A; Pasternak, Ofer; Bouix, Sylvain; Rathi, Yogesh; Bigler, Erin D; Stern, Robert A; Shenton, Martha E

    2015-05-01

    Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease confirmed at postmortem. Those at highest risk are professional athletes who participate in contact sports and military personnel who are exposed to repetitive blast events. All neuropathologically confirmed CTE cases, to date, have had a history of repetitive head impacts. This suggests that repetitive head impacts may be necessary for the initiation of the pathogenetic cascade that, in some cases, leads to CTE. Importantly, while all CTE appears to result from repetitive brain trauma, not all repetitive brain trauma results in CTE. Magnetic resonance imaging has great potential for understanding better the underlying mechanisms of repetitive brain trauma. In this review, we provide an overview of advanced imaging techniques currently used to investigate brain anomalies. We also provide an overview of neuroimaging findings in those exposed to repetitive head impacts in the acute/subacute and chronic phase of injury and in more neurodegenerative phases of injury, as well as in military personnel exposed to repetitive head impacts. Finally, we discuss future directions for research that will likely lead to a better understanding of the underlying mechanisms separating those who recover from repetitive brain trauma vs. those who go on to develop CTE.

  9. FEMA Hazard Mitigation Assistance Severe Repetitive Loss (SRL) Data

    Data.gov (United States)

    Department of Homeland Security — This dataset contains closed and obligated projects funded under the following Hazard Mitigation Assistance (HMA) grant programs: Severe Repetitive Loss (SRL). The...

  10. Repetitive control of electrically driven robot manipulators

    Science.gov (United States)

    Fateh, Mohammad Mehdi; Ahsani Tehrani, Hojjat; Karbassi, Seyed Mehdi

    2013-04-01

    This article presents a novel robust discrete repetitive control of electrically driven robot manipulators for tracking of a periodic trajectory. We propose a novel model, which presents the highly non-linear dynamics of robot manipulator in the form of linear discrete-time time-varying system. Based on the proposed model, we develop a two-term control law. The first term is an ordinary time-optimal and minimum-norm (TOMN) control by employing parametric controllers to guarantee stability. The second term is a novel robust control to improve the control performance in the face of uncertainties. The robust control estimates and compensates uncertainties including the parametric uncertainty, unmodelled dynamics and external disturbances. Performance of the proposed method is compared with two discrete methods, namely the TOMN control and an adaptive iterative learning (AIL) control. Simulation results confirm superiority of the proposed method in terms of the convergence speed and precision.

  11. Studies of the uncanny: the repetition factor

    Directory of Open Access Journals (Sweden)

    Julia Teitelroit Martins

    2011-06-01

    Full Text Available Freud’s essay The Uncanny (Das Unheimliche offers many indications for the comprehension of an aesthetics of the uncanny which deserve to be explored. Nonetheless, a concept traverses it from beginning to end: the return – which enables its reading under the light of Beyond the pleasure principle, written along the same span of time. Emphasis is given to the uncanny in the sense of repetition of the different – a paradox in terms, like the strangely familiar uncanny. In order to test the validity of an aesthetic reading under this perspective, follows an analysis of the brief short story “A terceira margem do rio” (“The third margin of the river”, by Guimarães Rosa.

  12. Object color affects identification and repetition priming.

    Science.gov (United States)

    Uttl, Bob; Graf, Peter; Santacruz, Pilar

    2006-10-01

    We investigated the influence of color on the identification of both non-studied and studied objects. Participants studied black and white and color photos of common objects and memory was assessed with an identification test. Consistent with our meta-analysis of prior research, we found that objects were easier to identify from color than from black and white photos. We also found substantial priming in all conditions, and study-to-test changes in an object's color reduced the magnitude of priming. Color-specific priming effects were large for color-complex objects, but minimal for color-simple objects. The pattern and magnitude of priming effects was not influenced either by the extent to which an object always appears in the same color (i.e., whether a color is symptomatic of an object) or by the object's origin (natural versus fabricated). We discuss the implications of our findings for theoretical accounts of object perception and repetition priming.

  13. Design and development of repetitive capacitor charging power supply based on series-parallel resonant converter topology.

    Science.gov (United States)

    Patel, Ankur; Nagesh, K V; Kolge, Tanmay; Chakravarthy, D P

    2011-04-01

    LCL resonant converter based repetitive capacitor charging power supply (CCPS) is designed and developed in the division. The LCL converter acts as a constant current source when switching frequency is equal to the resonant frequency. When both resonant inductors' values of LCL converter are same, it results in inherent zero current switching (ZCS) in switches. In this paper, ac analysis with fundamental frequency approximation of LCL resonant tank circuit, frequency dependent of current gain converter followed by design, development, simulation, and practical result is described. Effect of change in switching frequency and resonant frequency and change in resonant inductors ratio on CCPS will be discussed. An efficient CCPS of average output power of 1.2 kJ/s, output voltage 3 kV, and 300 Hz repetition rate is developed in the division. The performance of this CCPS has been evaluated in the laboratory by charging several values of load capacitance at various repetition rates. These results indicate that this design is very feasible for use in capacitor-charging applications. © 2011 American Institute of Physics

  14. The Effects of Gender and Age on Repetitive and/or Restricted Behaviors and Interests in Adults with Autism Spectrum Disorders and Intellectual Disability

    Science.gov (United States)

    Hattier, Megan A.; Matson, Johnny L.; Tureck, Kimberly; Horovitz, Max

    2011-01-01

    Frequency of repetitive and/or restricted behaviors and interests (RRBIs) was assessed in 140 adults with autism spectrum disorders (ASDs) and severe or profound intellectual disability (ID). The associations of gender and age range were analyzed with RRBI frequency which was obtained using the Stereotypies subscale of the "Diagnostic…

  15. A Repetitive Nanosecond Pulse Source for Generation of Large Volume Streamer Discharge

    Institute of Scientific and Technical Information of China (English)

    TAO Fengbo; ZHANG Qiaogen; GAO Bo; WANG Hu; LI Zhou

    2008-01-01

    Using a unipolar pulse with the rise time and the pulse duration in the order of microsecond as the primary pulse,a nanosecond pulse with the repetitive frequency of several kilohertz is generated by a spark gap switch.By varying both the inter-pulse duration and the pulse frequency,the voltage recovery rate of the spark gap switch is investigated at different working conditions such as the gas pressure,the gas composition as well as the bias voltage.The results reveal that either increase in gas pressure or addition of SF6 to the air can increase the voltage recovery rate.The effect of gas composition on the voltage recovery rate is discussed based on the transferring and distribution of the residual space charges.The repetitive nanosecond pulse source is also applied to the generation of large volume,and the discharge currents are measured to investigate the effect of pulse repetition rate on the large volume streamer discharge.

  16. Compact X-ray Source using a High Repetition Rate Laser and Copper Linac

    CERN Document Server

    Graves, W S; Brown, P; Carbajo, S; Dolgashev, V; Hong, K -H; Ihloff, E; Khaykovich, B; Lin, H; Murari, K; Nanni, E A; Resta, G; Tantawi, S; Zapata, L E; Kärtner, F X; Moncton, D E

    2014-01-01

    A design for a compact x-ray light source (CXLS) with flux and brilliance orders of magnitude beyond existing laboratory scale sources is presented. The source is based on inverse Compton scattering of a high brightness electron bunch on a picosecond laser pulse. The accelerator is a novel high-efficiency standing-wave linac and RF photoinjector powered by a single ultrastable RF transmitter at x-band RF frequency. The high efficiency permits operation at repetition rates up to 1 kHz, which is further boosted to 100 kHz by operating with trains of 100 bunches of 100 pC charge, each separated by 5 ns. The 100 kHz repetition rate is orders of magnitude beyond existing high brightness copper linacs. The entire accelerator is approximately 1 meter long and produces hard x-rays tunable over a wide range of photon energies. The colliding laser is a Yb:YAG solid-state amplifier producing 1030 nm, 100 mJ pulses at the same 1 kHz repetition rate as the accelerator. The laser pulse is frequency-doubled and stored for m...

  17. A long-pulse repetitive operation magnetically insulated transmission line oscillator.

    Science.gov (United States)

    Fan, Yu-Wei; Zhong, Hui-Huang; Zhang, Jian-De; Shu, Ting; Liu, Jin Liang

    2014-05-01

    The improved magnetically insulated transmission line oscillator (MILO) is a gigawatt-class L-band high power microwave tube. It has allowed us to generate 3.1 GW pulse of 40 ns duration in the single-pulse operation and 500 MW pulse of 25 ns duration in the repetition rate operation. However, because of the severe impedance mismatch, the power conversion efficiency is only about 4% in the repetition rate operation. In order to eliminate the impedance mismatch and obtain repetitive long-pulse high-power microwave (HPM), a series of experiments are carried out and the recent progress is presented in this paper. In the single-pulse operation, when the diode voltage is 466 kV and current is 41.6 kA, the radiated microwave power is above 2.2 GW, the pulse duration is above 102 ns, the microwave frequency is about 1.74 GHz, and the power conversion efficiency is about 11.5%. In the repetition rate operation, under the condition of the diode voltage about 400 kV, beam current about 38 kA, the radiated microwave power is about 1.0 GW, the pulse duration is about 85 ns. Moreover, the radiated microwave power and the pulse duration decline little by little when the shot numbers increase gradually. The experimental results show that the impedance matching is a vital factor for HPM systems and one of the major technical challenges is to improve the cathode for the repetition rate operation MILO.

  18. In search of a consensus terminology in the field of platelet concentrates for surgical use: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), fibrin gel polymerization and leukocytes.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Bielecki, Tomasz; Mishra, Allan; Borzini, Piero; Inchingolo, Francesco; Sammartino, Gilberto; Rasmusson, Lars; Evert, Peter A

    2012-06-01

    In the field of platelet concentrates for surgical use, most products are termed Platelet-Rich Plasma (PRP). Unfortunately, this term is very general and incomplete, leading to many confusions in the scientific database. In this article, a panel of experts discusses this issue and proposes an accurate and simple terminology system for platelet concentrates for surgical use. Four main categories of products can be easily defined, depending on their leukocyte content and fibrin architecture: Pure Platelet-Rich Plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; Leukocyteand Platelet-Rich Plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan, Angel or GPS PRP; Pure Plaletet-Rich Fibrin (P-PRF), such as Fibrinet; and Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Choukroun's PRF. P-PRP and L-PRP refer to the unactivated liquid form of these products, their activated versions being respectively named P-PRP gels and L-PRP gels. The purpose of this search for a terminology consensus is to plead for a more serious characterization of these products. Researchers have to be aware of the complex nature of these living biomaterials, in order to avoid misunderstandings and erroneous conclusions. Understanding the biomaterials or believing in the magic of growth factors ? From this choice depends the future of the field.

  19. Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Andia, Isabel; Zumstein, Matthias A; Zhang, Chang-Qing; Pinto, Nelson R; Bielecki, Tomasz

    2014-01-01

    Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

  20. Biomechanical Stability of Dental Implants in Augmented Maxillary Sites: Results of a Randomized Clinical Study with Four Different Biomaterials and PRF and a Biological View on Guided Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Troedhan Angelo

    2015-01-01

    Full Text Available Introduction. Bone regenerates mainly by periosteal and endosteal humoral and cellular activity, which is given only little concern in surgical techniques and choice of bone grafts for guided bone regeneration. This study investigates on a clinical level the biomechanical stability of augmented sites in maxillary bone when a new class of moldable, self-hardening calcium-phosphate biomaterials (SHB is used with and without the addition of Platelet Rich Fibrin (aPRF in the Piezotome-enhanced subperiosteal tunnel-technique (PeSPTT. Material and Methods. 82 patients with horizontal atrophy of anterior maxillary crest were treated with PeSPTT and randomly assigned biphasic (60% HA/40% bTCP or monophasic (100% bTCP SHB without or with addition of aPRF. 109 implants were inserted into the augmented sites after 8.3 months and the insertion-torque-value (ITV measured as clinical expression of the (biomechanical stability of the augmented bone and compared to ITVs of a prior study in sinus lifting. Results. Significant better results of (biomechanical stability almost by two-fold, expressed by higher ITVs compared to native bone, were achieved with the used biomaterials and more constant results with the addition of aPRF. Conclusion. The use of SHB alone or combined with aPRF seems to be favourable to achieve a superior (biomechanical stable restored alveolar bone.

  1. Fast induction of biosynthetic polysaccharide genes lpxA, lpxE, and rkpI of Rhizobium sp. strain PRF 81 by common bean seed exudates is indicative of a key role in symbiosis.

    Science.gov (United States)

    Oliveira, Luciana Ruano; Rodrigues, Elisete Pains; Marcelino-Guimarães, Francismar Corrêa; Oliveira, André Luiz Martinez; Hungria, Mariangela

    2013-06-01

    Rhizobial surface polysaccharides (SPS) are, together with nodulation (Nod) factors, recognized as key molecules for establishment of rhizobia-legume symbiosis. In Rhizobium tropici, an important nitrogen-fixing symbiont of common bean (Phaseolus vulgaris L.), molecular structures and symbiotic roles of the SPS are poorly understood. In this study, Rhizobium sp. strain PRF 81 genes, belonging to the R. tropici group, were investigated: lpxA and lpxE, involved in biosynthesis and modification of the lipid-A anchor of lipopolysaccharide (LPS), and rkpI, involved in synthesis of a lipid carrier required for production of capsular polysaccharides (KPS). Reverse transcription quantitative PCR (RT-qPCR) analysis revealed, for the first time, that inducers released from common bean seeds strongly stimulated expression of all three SPS genes. When PRF 81 cells were grown for 48 h in the presence of seed exudates, twofold increases (p PRF81 and of the type strain of R. tropici CIAT899(T)clustered with orthologous Rhizobium radiobacter and were more related to R. etli and Rhizobium leguminosarum, while rkpI was closer to the Sinorhizobium sp. group. Upregulation of lpxE, lpxA, and rkpI genes suggests that seed exudates can modulate production of SPS of Rhizobium sp. PRF81, leading to cell wall changes necessary for symbiosis establishment.

  2. PENGEMBANGAN TEPUNG KAYA PROTEIN (TKP dari KORO KOMAK (Lablab purpureus (L Sweet DAN KORO KRATOK (Phaseolus lunatus [Development of Protein Rich Flour (PRF from Hyacinth Bean (Lablab purpureus (L Sweet and Lima bean (Phaseolus lunatus

    Directory of Open Access Journals (Sweden)

    Ahmad Nafi1

    2006-12-01

    Full Text Available With respect to high content of carbohydrate and protein, Protein Rich Flour (PRF were developed from non-oilseed legumes i.e. hyacinth bean (Lablab purpureus (L Sweet and lima bean (Phaseolus lunatus PRF. PRFs were prepared using water and NaOH solution (0.01N as extraction solvent. After precipitation in isoelectric point (pHs the PRFs produced were characterized to determine the potential applications. The results showed that PRF from hyacinth bean which extracted by water was the best product with yield of 31.19%, protein content 58.41±4.45%, solubility 82-100% and oil holding capacity 93.92±9.19. Moreover pepsin-digestibility of the hyacinth bean PRF was higher (8.29±0.34% than soybean protein isolate (7.10±0.37% or casein (7.04±0.14%. Based on their characteristics, PRFs regarded as potential to be developed as novel food ingredient.

  3. Cord blood PRF1 methylation patterns and risk of lower respiratory tract infections in infants: findings from the Ulm Birth Cohort.

    Science.gov (United States)

    Elgizouli, Magdeldin; Logan, Chad; Nieters, Alexandra; Brenner, Hermann; Rothenbacher, Dietrich

    2015-01-01

    Lower respiratory tract infections (LRTIs) are a major cause of morbidity in children. DNA methylation provides a mechanism for transmitting environmental effects on the genome, but its potential role in LRTIs is not well studied. We investigated the methylation pattern of an enhancer region of the immune effector gene perforin-1 (PRF1), which encodes a cytolytic molecule of cytotoxic T lymphocytes (CTLs) and natural killer cells (NK), in cord blood DNA of children recruited in a German birth cohort in association with LRTIs in the first year of life.Pyrosequencing was used to determine the methylation levels of target cytosine-phosphate-guanines (CpGs) in a 2-stage case-control design. Cases were identified as children who developed ≥2 episodes of physician-recorded LRTIs during the first year of life and controls as children who had none. Discovery (n = 87) and replication (n = 90) sets were arranged in trios of 1 case and 2 controls matched for sex and season of birth.Logistic regression analysis revealed higher levels of methylation at a CpG that corresponds to a signal transducer and activator of transcription 5 (STAT5) responsive enhancer in the discovery (odds ratio [OR] per 1% methylation difference 1.24, 95% confidence interval [CI] 1.03-1.50) and replication (OR per 1% methylation difference 1.25, 95% CI 1.04-1.50) sets. Adjustment for having siblings old in the discovery and replication sets produced ORs of 1.19 (95% CI 0.98-1.45) and 1.25 (95% CI 1.04-1.50), respectively. Adjustment for gestational age in the replication set had no influence on the results. Methylation levels at adjacent CpGs varied with maternal age, smoking, education, and having siblings old.Our data support an association between cord blood PRF1 enhancer methylation patterns and subsequent risk of LRTIs in infants. Methylation levels at specific CpGs of the PRF1 enhancer varied according to maternal and family environmental factors suggesting a role for DNA methylation in

  4. Comparison of the Effect of PRP, PRF and Induced Bleeding in the Revascularization of Teeth with Necrotic Pulp and Open Apex: A Triple Blind Randomized Clinical Trial.

    Science.gov (United States)

    Shivashankar, Vasundara Yayathi; Johns, Dexton Antony; Maroli, Ramesh Kumar; Sekar, Mahalaxmi; Chandrasekaran, Rathinavel; Karthikeyan, Shanmugavel; Renganathan, Senthil Kumar

    2017-06-01

    Treatment of a tooth with necrotic pulp and open apex is a special challenge to the clinicians. Apexification with calcium hydroxide and MTA barrier technique fails to induce continued root maturation which makes the tooth susceptible to root fracture. Hence, an ideal outcome for such a tooth should be regeneration of pulp like tissue into the root canal capable of continuing normal root maturation. This study aims to compare the effect of Platelet Rich Fibrin (PRF), induced bleeding technique and Platelet Rich Plasma (PRP) in the revascularization of tooth with necrotic pulp and open apex. The main objectives of the study were to: (a) Radiographically evaluate the continuation of root development, increase in the dentin wall thickness and narrowing of canal space, apical closure and resolution of the periapical lesion; and to (b) To clinically evaluate the response to pulp sensibility testing and response to percussion and palpation tests. Sixty patients (6 to 28 years) with necrotic immature permanent tooth were randomly categorised into three groups after the root canal disinfection procedure. PRF as scaffolding material (Group A: n=20), revascularization with conventional induced bleeding technique (Group B: n=20), and PRP as the biomaterial (Group C: n=20). The primary outcome variable was measured using Periapical Index (PAI) (for periapical healing), Chen and Chen index (for apical responses), Schei's ruler (for root lengthening and root thickening) and other clinical parameters. The Chi-square test was used to interpret the data among the three groups at the end of 12 months for the variables root lengthening and lateral wall thickness. ANOVA test was performed to compare the mean of the PAI scores of the three groups at preoperative stage and 12 months. If statistically significant, Bonferroni test was done to compare the outcome among the three groups. The significant level was set at pPRF and induced bleeding technique with respect to periapical wound

  5. Platelet-Rich Fibrin (PRF) in Implants Dentistry in Combination with New Bone Regenerative Flapless Technique: Evolution of the Technique and Final Results.

    Science.gov (United States)

    Cortese, Antonio; Pantaleo, Giuseppe; Amato, Massimo; Howard, Candace M; Pedicini, Lorenzo; Claudio, Pier Paolo

    2017-01-01

    Most common techniques for alveolar bone augmentation are guided bone regeneration (GBR) and autologous bone grafting. GBR studies demonstrated long-term reabsorption using heterologous bone graft. A general consensus has been achieved in implant surgery for a minimal amount of 2 mm of healthy bone around the implant. A current height loss of about 3-4 mm will result in proper deeper implant insertion when alveolar bone expansion is not planned because of the dome shape of the alveolar crest. To manage this situation a split crest technique has been proposed for alveolar bone expansion and the implants' insertion in one stage surgery. Platelet-rich fibrin (PRF) is a healing biomaterial with a great potential for bone and soft tissue regeneration without inflammatory reactions, and may be used alone or in combination with bone grafts, promoting hemostasis, bone growth, and maturation. The aim of this study was to demonstrate the clinical effectiveness of PRF combined with a new split crest flapless modified technique in 5 patients vs. 5 control patients. Ten patients with horizontal alveolar crests deficiency were treated in this study, divided into 2 groups: Group 1 (test) of 5 patients treated by the flapless split crest new procedure; Group 2 (control) of 5 patients treated by traditional technique with deeper insertion of smaller implants without split crest. The follow-up was performed with x-ray orthopantomography and intraoral radiographs at T0 (before surgery), T1 (operation time), T2 (3 months) and T3 (6 months) post-operation. All cases were successful; there were no problems at surgery and post-operative times. All implants succeeded osteointegration and all patients underwent uneventful prosthetic rehabilitation. Mean height bone loss was 1 mm, measured as bone-implant most coronal contact (Δ-BIC), and occurred at immediate T2 post-operative time (3 months). No alveolar bone height loss was detected at implant insertion time, which was instead

  6. Optimization of graffiti removal on natural stone by means of high repetition rate UV laser

    Science.gov (United States)

    Fiorucci, M. P.; López, A. J.; Ramil, A.; Pozo, S.; Rivas, T.

    2013-08-01

    The use of laser for graffiti removal is a promising alternative to conventional cleaning methods, though irradiation parameters must be carefully selected in order to achieve the effective cleaning without damaging the substrate, especially when referring to natural stone. From a practical point of view, once a safe working window is selected, it is necessary to determine the irradiation conditions to remove large paint areas, with minimal time consumption. The aim of this paper is to present a systematic procedure to select the optimum parameters for graffiti removal by means of the 3rd harmonic of a high repetition rate nanosecond Nd:YVO4 laser. Ablation thresholds of four spray paint colors were determined and the effect of pulse repetition frequency, beam diameter and line scan separation was analyzed, obtaining a set of values which optimize the ablation process.

  7. The impacts of magnetic field on repetitive nanosecond pulsed dielectric barrier discharge in air

    Science.gov (United States)

    Liu, Yidi; Qi, Haicheng; Fan, Zhihui; Yan, Huijie; Ren, ChunSheng

    2016-11-01

    In this paper, the impacts of the parallel magnetic field on the repetitive nanosecond pulsed dielectric barrier discharge (DBD) are experimentally investigated by optical and electrical measurements. The DBD is generated between two parallel-plate electrodes in the ambient air with the stationary magnetic field on the order of 1 T. The experimental results show that additional microdischarge channels are generated and the photocurrent intensity of the plasma is increased by the magnetic field. The microdischarge channels develop along the magnetic field lines and the diffuse background emission of the discharge is stronger in the DBD with the magnetic field. As the pulse repetition frequency decreases from 1200 Hz to 100 Hz, only the photocurrent intensity of the third discharge that occurred at about 500 ns is noticeably increased by the additional magnetic field. It is believed that the enhancement of the memory effect and the confinement of the magnetic field on electrons are the main reasons.

  8. Optimization of graffiti removal on natural stone by means of high repetition rate UV laser

    Energy Technology Data Exchange (ETDEWEB)

    Fiorucci, M.P., E-mail: m.p.fiorucci@udc.es [Centro de Investigacións Tecnolóxicas, Universidade da Coruña, 15403 Ferrol (Spain); Dpto. Enxeñaría dos Recursos Naturais e Medio Ambiente, E.T.S.E. Minas, Universidade de Vigo, 36200 Vigo (Spain); López, A.J., E-mail: ana.xesus.lopez@udc.es [Centro de Investigacións Tecnolóxicas, Universidade da Coruña, 15403 Ferrol (Spain); Ramil, A., E-mail: alberto.ramil@udc.es [Centro de Investigacións Tecnolóxicas, Universidade da Coruña, 15403 Ferrol (Spain); Pozo, S., E-mail: ipozo@uvigo.es [Dpto. Enxeñaría dos Recursos Naturais e Medio Ambiente, E.T.S.E. Minas, Universidade de Vigo, 36200 Vigo (Spain); Rivas, T., E-mail: trivas@uvigo.es [Dpto. Enxeñaría dos Recursos Naturais e Medio Ambiente, E.T.S.E. Minas, Universidade de Vigo, 36200 Vigo (Spain)

    2013-08-01

    The use of laser for graffiti removal is a promising alternative to conventional cleaning methods, though irradiation parameters must be carefully selected in order to achieve the effective cleaning without damaging the substrate, especially when referring to natural stone. From a practical point of view, once a safe working window is selected, it is necessary to determine the irradiation conditions to remove large paint areas, with minimal time consumption. The aim of this paper is to present a systematic procedure to select the optimum parameters for graffiti removal by means of the 3rd harmonic of a high repetition rate nanosecond Nd:YVO{sub 4} laser. Ablation thresholds of four spray paint colors were determined and the effect of pulse repetition frequency, beam diameter and line scan separation was analyzed, obtaining a set of values which optimize the ablation process.

  9. The golden ratio of gait harmony: repetitive proportions of repetitive gait phases.

    Science.gov (United States)

    Iosa, Marco; Fusco, Augusto; Marchetti, Fabio; Morone, Giovanni; Caltagirone, Carlo; Paolucci, Stefano; Peppe, Antonella

    2013-01-01

    In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number φ known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with φ, the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (F = 0.870, P = 0.422, repeated measure analysis of variance) or from φ (P = 0.670, 0.820, 0.422, resp., t-tests). The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait.

  10. The Golden Ratio of Gait Harmony: Repetitive Proportions of Repetitive Gait Phases

    Directory of Open Access Journals (Sweden)

    Marco Iosa

    2013-01-01

    Full Text Available In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with , the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (, , repeated measure analysis of variance or from (, resp., t-tests. The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait.

  11. In vivo noninvasive thermometry for hyperthermia applications using the MRI-based proton-resonance-frequency method

    Energy Technology Data Exchange (ETDEWEB)

    De Poorter, J.; De Deene, Y.; Achten, E. [Ghent University (Belgium). Dept. of Magnetic Resonance; De Wagter, C. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; Thomsen, C. [Hvidovre Univ. (Denmark); Staahlberg, F. [Lund Univ. (Sweden). Dept. of Radiation Physics

    1995-12-01

    The lack of noninvasive temperature monitoring is seriously limiting hyperthermia treatment of deep-seated tumors. MRI methods exploit the temperature dependence of a physical property whose spatial distribution can be visualized. The Proton Resonance Frequency (PRF) as physical property was examined because phantom studies prove the high accuracy that can be obtained using this parameter. Thermal experiments were performed in human lower legs. The results show that in muscle tissue the three-dimensional temperature distribution can be evaluated with a mean spatial distribution of 2 millimetres, a temporal resolution of 2 minutes and an accuracy of about 1 degree Celsius. However, it is not possible to retrieve the temperature distribution in fat tissue using the PRF-method due to the predominance of susceptibility effects in fat. The susceptibility effects are a consequence of the temperature dependence of the susceptibility constants. Experimental data on these dependencies were obtained and the magnitude of these effects was modelled for some specific configurations. The susceptibility effects in muscle tissue can be neglected when precautions are made. The PRF method is an attractive tool to study time-varying temperature changes in muscle tissue.

  12. Use of repetitive transcranial magnetic stimulation for treatment in psychiatry.

    Science.gov (United States)

    Aleman, André

    2013-08-01

    The potential of noninvasive neurostimulation by repetitive transcranial magnetic stimulation (rTMS) for improving psychiatric disorders has been studied increasingly over the past two decades. This is especially the case for major depression and for auditory-verbal hallucinations in schizophrenia. The present review briefly describes the background of this novel treatment modality and summarizes evidence from clinical trials into the efficacy of rTMS for depression and hallucinations. Evidence for efficacy in depression is stronger than for hallucinations, although a number of studies have reported clinically relevant improvements for hallucinations too. Different stimulation parameters (frequency, duration, location of stimulation) are discussed. There is a paucity of research into other psychiatric disorders, but initial evidence suggests that rTMS may also hold promise for the treatment of negative symptoms in schizophrenia, obsessive compulsive disorder and post-traumatic stress disorder. It can be concluded that rTMS induces alterations in neural networks relevant for psychiatric disorders and that more research is needed to elucidate efficacy and underlying mechanisms of action.

  13. Repetitive transcranial magnetic stimulator with controllable pulse parameters

    Science.gov (United States)

    Peterchev, Angel V.; Murphy, David L.; Lisanby, Sarah H.

    2011-06-01

    The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 µs and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency.

  14. Characterizing Aciniform Silk Repetitive Domain Backbone Dynamics and Hydrodynamic Modularity

    Directory of Open Access Journals (Sweden)

    Marie-Laurence Tremblay

    2016-08-01

    Full Text Available Spider aciniform (wrapping silk is a remarkable fibrillar biomaterial with outstanding mechanical properties. It is a modular protein consisting, in Argiope trifasciata, of a core repetitive domain of 200 amino acid units (W units. In solution, the W units comprise a globular folded core, with five α-helices, and disordered tails that are linked to form a ~63-residue intrinsically disordered linker in concatemers. Herein, we present nuclear magnetic resonance (NMR spectroscopy-based 15N spin relaxation analysis, allowing characterization of backbone dynamics as a function of residue on the ps–ns timescale in the context of the single W unit (W1 and the two unit concatemer (W2. Unambiguous mapping of backbone dynamics throughout W2 was made possible by segmental NMR active isotope-enrichment through split intein-mediated trans-splicing. Spectral density mapping for W1 and W2 reveals a striking disparity in dynamics between the folded core and the disordered linker and tail regions. These data are also consistent with rotational diffusion behaviour where each globular domain tumbles almost independently of its neighbour. At a localized level, helix 5 exhibits elevated high frequency dynamics relative to the proximal helix 4, supporting a model of fibrillogenesis where this helix unfolds as part of the transition to a mixed α-helix/β-sheet fibre.

  15. Iconicity in Discourse: The Case of Repetition in Japanese.

    Science.gov (United States)

    Ishikawa, Minako

    This analysis of repeated utterances in Japanese conversational discourse focuses on repetition as an expression of iconicity. In the analysis of a 30-minute conversation among 4 Japanese speakers, the iconic meanings expressed by both reduplication and conversational repetition are highlighted. The iconicity characteristic of conversational data…

  16. Evidence-Based Behavioral Interventions for Repetitive Behaviors in Autism

    Science.gov (United States)

    Boyd, Brian A.; McDonough, Stephen G.; Bodfish, James W.

    2012-01-01

    Restricted and repetitive behaviors (RRBs) are a core symptom of autism spectrum disorders (ASD). There has been an increased research emphasis on repetitive behaviors; however, this research primarily has focused on phenomenology and mechanisms. Thus, the knowledge base on interventions is lagging behind other areas of research. The literature…

  17. Visual attention to advertising : The impact of motivation and repetition

    NARCIS (Netherlands)

    Pieters, RGM; Rosbergen, E; Hartog, M; Corfman, KP; Lynch, JG

    1996-01-01

    Using eye-tracking data, we examine the impact of motivation and repetition on visual attention to advertisements differing in argument quality. Our analyses indicate that repetition leads to an overall decrease in the amount of attention. However, while at first high motivation subjects attend to t

  18. On the Functions of Lexical Repetition in English Texts

    Institute of Scientific and Technical Information of China (English)

    XIAO Fuliang

    2016-01-01

    Lexical repetition, as a cohesive device of an English text, can help make up a cohesive and coherent text. Therefore, in English textual learning, it is helpful for students to know about different patterns and functions of lexical repetition to improve their English level and ability.

  19. Genomic basis of broad host range and environmental adaptability of Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 which are used in inoculants for common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Ormeño-Orrillo, Ernesto; Menna, Pâmela; Almeida, Luiz Gonzaga P; Ollero, Francisco Javier; Nicolás, Marisa Fabiana; Pains Rodrigues, Elisete; Shigueyoshi Nakatani, Andre; Silva Batista, Jesiane Stefânia; Oliveira Chueire, Ligia Maria; Souza, Rangel Celso; Ribeiro Vasconcelos, Ana Tereza; Megías, Manuel; Hungria, Mariangela; Martínez-Romero, Esperanza

    2012-12-27

    Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 are α-Proteobacteria that establish nitrogen-fixing symbioses with a range of legume hosts. These strains are broadly used in commercial inoculants for application to common bean (Phaseolus vulgaris) in South America and Africa. Both strains display intrinsic resistance to several abiotic stressful conditions such as low soil pH and high temperatures, which are common in tropical environments, and to several antimicrobials, including pesticides. The genetic determinants of these interesting characteristics remain largely unknown. Genome sequencing revealed that CIAT 899 and PRF 81 share a highly-conserved symbiotic plasmid (pSym) that is present also in Rhizobium leucaenae CFN 299, a rhizobium displaying a similar host range. This pSym seems to have arisen by a co-integration event between two replicons. Remarkably, three distinct nodA genes were found in the pSym, a characteristic that may contribute to the broad host range of these rhizobia. Genes for biosynthesis and modulation of plant-hormone levels were also identified in the pSym. Analysis of genes involved in stress response showed that CIAT 899 and PRF 81 are well equipped to cope with low pH, high temperatures and also with oxidative and osmotic stresses. Interestingly, the genomes of CIAT 899 and PRF 81 had large numbers of genes encoding drug-efflux systems, which may explain their high resistance to antimicrobials. Genome analysis also revealed a wide array of traits that may allow these strains to be successful rhizosphere colonizers, including surface polysaccharides, uptake transporters and catabolic enzymes for nutrients, diverse iron-acquisition systems, cell wall-degrading enzymes, type I and IV pili, and novel T1SS and T5SS secreted adhesins. Availability of the complete genome sequences of CIAT 899 and PRF 81 may be exploited in further efforts to understand the interaction of tropical rhizobia with common bean and other legume hosts.

  20. Preparation of Protein Retanning Agent PRF with Fatliquoring Property%加脂性蛋白质复鞣剂PRF的制备

    Institute of Scientific and Technical Information of China (English)

    国峰

    2001-01-01

    工业明胶经过多种改性技术处理可获得系列性能优良的皮革化学品。本文将水解明胶与烷基磺酰氯反应制备了加脂性蛋白质复鞣剂。初步应用表明,PRF具有良好的复鞣加脂效果和一定的填充性能。%By means of various modifying methods, series leather chemicals can be obtained fromgelatin. In this paper, hydrolytic gelatin reacts with alkanesulfony chloride to get the proteinretaunning agent PRF with fatliquoring property. Preliminary application results showed that it isa good retanning agent with

  1. Role of repetitive transcranial magnetic stimulation in stroke rehabilitation.

    Science.gov (United States)

    Pinter, Michaela M; Brainin, Michael

    2013-01-01

    In recent years, efforts have focused on investigating the neurophysiological changes that occur in the brain after stroke, and on developing novel strategies such as additional brain stimulation to enhance sensorimotor and cognitive recovery. In the 1990s, repetitive transcranial magnetic stimulation (rTMS) was introduced as a therapeutic tool for improving the efficacy of rehabilitation for recovery after stroke. It is evident that disturbances of interhemispheric processes after stroke result in a pathological hyperactivity of the intact hemisphere. The rationale of using rTMS as a complementary therapy is mainly to decrease the cortical excitability in regions that are presumed to hinder optimal recovery by low-frequency rTMS delivered to the unaffected hemisphere, while high-frequency rTMS delivered to the affected hemisphere facilitates cortical excitability. However, the exact mechanisms of how rTMS works are still under investigation. There is a growing body of research in stroke patients investigating the effect of rTMS on facilitating recovery by modifying cortical and subcortical networks. Clinical trials applying rTMS already yielded promising results in improving recovery of sensorimotor and cognitive functions. Altogether, in combination with conventional therapeutic approaches, rTMS has a potential to become a complementary strategy to enhance stroke recovery by modulating the excitability of targeted brain areas. In future studies, emphasis should be placed on selecting patient populations to determine whether treatment response depends on age, lesion acuteness, or stroke severity. Furthermore, it is important to identify parameters optimizing the beneficial effects of rTMS on stroke recovery, and to monitor their long-term effects.

  2. Mixed-frame and stationary-frame repetitive control schemes for compensating typical load and grid harmonics

    DEFF Research Database (Denmark)

    Loh, P.; Tang, Y.; Blaabjerg, Frede;

    2011-01-01

    In this study, repetitive current controllers operating in either the mixed or stationary frame are proposed for high-precision reference tracking and disturbance rejection of power converters. Both controllers use a proportional-resonant regulator in the stationary frame for regulating...... the positive- and negative-sequence fundamental currents, which are known to directly influence the flow of active and reactive power in most energy conversion systems. Moreover, for the tracking or compensation of harmonics, the controllers include a repetitive control path in either the synchronous...... or stationary frame, whose inherent feedback and feedforward structure is proven to resemble a bank of resonant filters in either reference frames. Unlike other existing controllers, the proposed repetitive controllers function by introducing multiple resonant peaks at only those harmonic frequencies typically...

  3. The impact of text repetition on content and function words during reading: further evidence from eye movements.

    Science.gov (United States)

    Chamberland, Cindy; Saint-Aubin, Jean; Légère, Marie-Andrée

    2013-06-01

    There is ample evidence that reading speed increases when participants read the same text more than once. However, less is known about the impact of text repetition as a function of word class. Some authors suggested that text repetition would mostly benefit content words with little or no effect on function words. In the present study, we examined the effect of multiple readings on the processing of content and function words. Participants were asked to read a short text two times in direct succession. Eye movement analyses revealed the typical multiple readings effect: Repetition decreased the time readers spent fixating words and the probability of fixating critical words. Most importantly, we found that the effect of multiple readings was of the same magnitude for content and function words, and for low- and high-frequency words. Such findings suggest that lexical variables have additive effects on eye movement measures in reading.

  4. Repetitive DNA Sequences in Wheat and Its Relatives

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-yong; LI Da-yong

    2001-01-01

    Repetitive DNA sequences form a large portion of eukaryote genomes. Using wheat ( Triticum )as a model, the classification, features and functions of repetitive DNA sequences in the Tritieeae grass tribe is reviewed as well as the role of these sequences in genome differentiation, control and regulation of homologous chromosome synapsis and pairing. Transposable elements, as an important portion of dispersed repetitives,may play an essential role in gene mutation of the host. Dynamic models for change of copy number and sequences of the repetitive family are also presented after the models of Charlesworth et al. Application of repetitive DNA sequences in the study of evolution, chromosome fingerprinting and marker assisted gene transfer and breeding are described by taking wheat as an example.

  5. Nonword Repetition and Speech Motor Control in Children

    Directory of Open Access Journals (Sweden)

    Christina Reuterskiöld

    2015-01-01

    Full Text Available This study examined how familiarity of word structures influenced articulatory control in children and adolescents during repetition of real words (RWs and nonwords (NWs. A passive reflective marker system was used to track articulator movement. Measures of accuracy were obtained during repetition of RWs and NWs, and kinematic analysis of movement duration and variability was conducted. Participants showed greater consonant and vowel accuracy during RW than NW repetition. Jaw movement duration was longer in NWs compared to RWs across age groups, and younger children produced utterances with longer jaw movement duration compared to older children. Jaw movement variability was consistently greater during repetition of NWs than RWs in both groups of participants. The results indicate that increases in phonological short-term memory demands affect articulator movement. This effect is most pronounced in younger children. A range of skills may develop during childhood, which supports NW repetition skills.

  6. Transgenerational effects of environmental enrichment on repetitive motor behavior development.

    Science.gov (United States)

    Bechard, Allison R; Lewis, Mark H

    2016-07-01

    The favorable consequences of environmental enrichment (EE) on brain and behavior development are well documented. Much less is known, however, about transgenerational benefits of EE on non-enriched offspring. We explored whether transgenerational effects of EE might extend to the development of repetitive motor behaviors in deer mice. Repetitive motor behaviors are invariant patterns of movement that, across species, can be reduced by EE. We found that EE not only attenuated the development of repetitive behavior in dams, but also in their non-enriched offspring. Moreover, maternal behavior did not seem to mediate the transgenerational effect we found, although repetitive behavior was affected by reproductive experience. These data support a beneficial transgenerational effect of EE on repetitive behavior development and suggest a novel benefit of reproductive experience.

  7. Self-controlled KR schedules: does repetition order matter?

    Science.gov (United States)

    Patterson, Jae T; Carter, Michael J; Hansen, Steve

    2013-08-01

    The impact of an experimenter-defined repetition schedule on the utility of a self-controlled KR context during motor skill acquisition was examined. Participants were required to learn three novel spatial-temporal tasks in either a random or blocked repetition schedule with or without the opportunity to control their KR. Results from the retention period showed that participants provided control over their KR schedule in a random repetition schedule demonstrated superior learning. However, performance measures from the transfer test showed that, independent of repetition schedule, learners provided the opportunity to control their KR schedule demonstrated superior transfer performance compared to their yoked counterparts. The dissociated impact of repetition schedule and self-controlled KR schedules on retention and transfer is discussed.

  8. Impaired speech repetition and left parietal lobe damage.

    Science.gov (United States)

    Fridriksson, Julius; Kjartansson, Olafur; Morgan, Paul S; Hjaltason, Haukur; Magnusdottir, Sigridur; Bonilha, Leonardo; Rorden, Christopher

    2010-08-18

    Patients with left hemisphere damage and concomitant aphasia usually have difficulty repeating others' speech. Although impaired speech repetition, the primary symptom of conduction aphasia, has been associated with involvement of the left arcuate fasciculus, its specific lesion correlate remains elusive. This research examined speech repetition among 45 stroke patients who underwent aphasia testing and MRI examination. Based on lesion-behavior mapping, the primary structural damage most closely associated with impaired speech repetition was found in the posterior portion of the left arcuate fasciculus. However, perfusion-weighted MRI revealed that tissue dysfunction, in the form of either frank damage or hypoperfusion, to the left inferior parietal lobe, rather than the underlying white matter, was associated with impaired speech repetition. This latter result suggests that integrity of the left inferior parietal lobe is important for speech repetition and, as importantly, highlights the importance of examining cerebral perfusion for the purpose of lesion-behavior mapping in acute stroke.

  9. Repetition and Emotive Communication in Music Versus Speech

    Directory of Open Access Journals (Sweden)

    Elizabeth Hellmuth eMargulis

    2013-04-01

    Full Text Available Music and speech are often placed alongside one another as comparative cases. Their relative overlaps and disassociations have been well explored (e.g. Patel, 2010. But one key attribute distinguishing these two domains has often been overlooked: the greater preponderance of repetition in music in comparison to speech. Recent fMRI studies have shown that familiarity – achieved through repetition – is a critical component of emotional engagement with music (Pereira et al., 2011. If repetition is fundamental to emotional responses to music, and repetition is a key distinguisher between the domains of music and speech, then close examination of the phenomenon of repetition might help clarify the ways that music elicits emotion differently than speech.

  10. Physical Characteristics Underpinning Repetitive Lunging in Fencing.

    Science.gov (United States)

    Turner, Anthony N; Marshall, Geoff; Phillips, James; Noto, Angelo; Buttigieg, Conor; Chavda, Shyam; Downing, William; Atlay, Nathan; Dimitriou, Lygeri; Kilduff, Laim

    2016-11-01

    Turner, AN, Marshall, G, Phillips, J, Noto, A, Buttigieg, C, Chavda, S, Downing, W, Atlay, N, Dimitriou, L, and Kilduff, L. Physical characteristics underpinning repetitive lunging in fencing. J Strength Cond Res 30(11): 3134-3139, 2016-Given the repetitive demand to execute lunging and changes in direction within fencing, the ability to sustain these at maximal capacity is fundamental to performance. The aim of this study was threefold. First, to provide normative values for this variable referred to as repeat lunge ability (RLA) and second to identify the physical characteristics that underpin it. Third, was to establish if a cause and effect relationship existed by training the associated characteristics. Assessment of lower-body power, reactive strength, speed, change of direction speed (CODS), and a sport-specific RLA were conducted on senior and junior elite male fencers (n = 36). Fencers were on average (±SD) 18.9 ± 3.2 years of age, 174.35 ± 10.42 cm tall, 70.67 ± 7.35 kg in mass, and 8.5 ± 4.2 years fencing experience. The RLA test had average work times of 16.03 ± 1.40 seconds and demonstrated "large" to "very large" associations with all tested variables, but in particular CODS (r = 0.70) and standing broad jump (SBJ; r = -0.68). Through linear regression analysis, these also provided a 2-predictor model accounting for 61% of the common variance associated with RLA. A cause and effect relationship with SBJ and CODS was confirmed by the training group, where RLA performance in these fencers improved from 15.80 ± 1.07 to 14.90 ± 0.86 seconds, with the magnitude of change reported as "moderate" (effect size (ES) = 0.93). Concurrent improvements were also noted in both SBJ (216.86 ± 17.15 vs. 221.71 ± 17.59 cm) and CODS (4.44 ± 0.29 vs. 4.31 ± 0.09 seconds) and while differences were only significant in SBJ, magnitudes of change were classed as "small" (ES = 0.28) and "moderate" (ES = 0.61), respectively. In conclusion, to improve RLA strength

  11. Simultaneous Analysis of Wnt and NF-κB Signaling Pathways in Doxorubicin Sensitive and Methotrexate Resistant PLC/ PRF/5 Cells.

    Science.gov (United States)

    Shojaie, Nasrin; Ghaffari, Seyed Mahmood

    2016-01-01

    Multi-drug resistance (MDR) is a controversial issue in traditional chemo- therapy of aggressive cancers, including hepatocellular carcinoma. The major cause of MDR is suggested to be the aberrant activation of the main signaling pathways such as Wnt and nuclear factor kappa-light-chain-enhancer of activated B cells (NF- κB) which have key roles in the maintenance of cancer stem cells (CSCs). Therefore, the evaluation of their alterations could be essential in chemo-resistant cancers such as Hepatocellular carcinoma. The main purpose of this study was to investigate the alteration of the mentioned pathways in the chemotherapy resistant cancer cells by assessing their major molecular parameters. In this experimental study, methylthiazol tetrazolium (MTT) assay, acridine orange/ethidium bromide (AO/EtBr) and Hoechst 33342 staining, DNA fragmentation and colony formation methods were employed to investigate the cytotoxic effects of methotrexate (MTX) and doxorubicin (DOX) on PLC/PRF/5 cells. Moreover, the expression of 11 important genes involved in MDR was performed by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). PLC/PRF/5 cells (Alexander) were sensitive to DOX and normally resist- ant to MTX. In addition, the results obtained from RT-PCR analysis revealed that β-catenin expression was significantly reduced and ABCG2 significantly overex- pressed 4.85 and 3.34 times (P value<0.05) in DOX and MTX treated cells, respec- tively. Furthermore, a considerable expression of HIF-1α and p65 were detected only in MTX-resistant cells. Anti-cancer drugs may have more than one target in tumor cells. They not only participate in deregulation of Wnt but also alter NF-κB activation. Moreover, HIF-1α was the only anti-apoptotic protein that was significantly induced in the chem- oresistant cells.

  12. Reliability and validity of the Spanish version of the Child Health and Illness Profile (CHIP Child-Edition, Parent Report Form (CHIP-CE/PRF

    Directory of Open Access Journals (Sweden)

    Tebé Cristian

    2010-08-01

    Full Text Available Abstract Background The objectives of the study were to assess the reliability, and the content, construct, and convergent validity of the Spanish version of the CHIP-CE/PRF, to analyze parent-child agreement, and compare the results with those of the original U.S. version. Methods Parents from a representative sample of children aged 6-12 years were selected from 9 primary schools in Barcelona. Test-retest reliability was assessed in a convenience subsample of parents from 2 schools. Parents completed the Spanish version of the CHIP-CE/PRF. The Achenbach Child Behavioural Checklist (CBCL was administered to a convenience subsample. Results The overall response rate was 67% (n = 871. There was no floor effect. A ceiling effect was found in 4 subdomains. Reliability was acceptable at the domain level (internal consistency = 0.68-0.86; test-retest intraclass correlation coefficients = 0.69-0.85. Younger girls had better scores on Satisfaction and Achievement than older girls. Comfort domain score was lower (worse in children with a probable mental health problem, with high effect size (ES = 1.45. The level of parent-child agreement was low (0.22-0.37. Conclusions The results of this study suggest that the parent version of the Spanish CHIP-CE has acceptable psychometric properties although further research is needed to check reliability at sub-domain level. The CHIP-CE parent report form provides a comprehensive, psychometrically sound measure of health for Spanish children 6 to 12 years old. It can be a complementary perspective to the self-reported measure or an alternative when the child is unable to complete the questionnaire. In general, the results are similar to the original U.S. version.

  13. Identification of Cancer Stem Cell Subpopulations of CD34+ PLC/PRF/5 That Result in Three Types of Human Liver Carcinomas

    Science.gov (United States)

    Park, Su Cheol; Nguyen, Ngoc Tue; Eun, Jong Ryeol; Zhang, Yanling; Jung, Yong Jin; Tschudy-Seney, Benjamin; Trotsyuk, Artem; Lam, Alexander; Ramsamooj, Rajendra; Zhang, Yanghong; Theise, Neil D.; Zern, Mark A.

    2015-01-01

    CD34+ stem cells play an important role during liver development and regeneration. Thus, we hypothesized that some human liver carcinomas (HLCs) might be derived from transformed CD34+ stem cells. Here, we determined that a population of CD34+ cells isolated from PLC/PRF/5 hepatoma cells (PLC) appears to function as liver cancer stem cells (LCSCs) by forming HLCs in immunodeficient mice with as few as 100 cells. Moreover, the CD34+ PLC subpopulation cells had an advantage over CD34− PLCs at initiating tumors. Three types of HLCs were generated from CD34+ PLC: hepatocellular carcinomas (HCCs); cholangiocarcinomas (CC); and combined hepatocellular cholangiocarcinomas (CHCs). Tumors formed in mice transplanted with 12 subpopulations and 6 progeny subpopulations of CD34+ PLC cells. Interestingly, progenies with certain surface antigens (CD133, CD44, CD90, or EPCAM) predominantly yielded HCCs. CD34+ PLCs that also expressed OV6 and their progeny OV6+ cells primarily produced CHC and CC. This represents the first experiment to demonstrate that the OV6+ antigen is associated with human CHC and CC. CD34+ PLCs that also expressed CD31 and their progeny CD31+ cells formed CHCs. Gene expression patterns and tumor cell populations from all xenografts exhibited diverse patterns, indicating that tumor-initiating cells (TICs) with distinct antigenic profiles contribute to cancer cell heterogeneity. Therefore, we identified CD34+ PLC cells functioning as LCSCs generating three types of HLCs. Eighteen subpopulations from one origin had the capacity independently to initiate tumors, thus functioning as TICs. This finding has broad implications for better understanding of the multistep model of tumor initiation and progression. Our finding also indicates that CD34+ PLCs that also express OV6 or CD31 result in types of HLCs. This is the first report that PLC/PRF/5 subpopulations expressing CD34 in combination with particular antigens defines categories of HLCs, implicating a

  14. Identification of cancer stem cell subpopulations of CD34(+) PLC/PRF/5 that result in three types of human liver carcinomas.

    Science.gov (United States)

    Park, Su Cheol; Nguyen, Ngoc Tue; Eun, Jong Ryeol; Zhang, Yanling; Jung, Yong Jin; Tschudy-Seney, Benjamin; Trotsyuk, Artem; Lam, Alexander; Ramsamooj, Rajendra; Zhang, Yanghong; Theise, Neil D; Zern, Mark A; Duan, Yuyou

    2015-04-15

    CD34(+) stem cells play an important role during liver development and regeneration. Thus, we hypothesized that some human liver carcinomas (HLCs) might be derived from transformed CD34(+) stem cells. Here, we determined that a population of CD34(+) cells isolated from PLC/PRF/5 hepatoma cells (PLC) appears to function as liver cancer stem cells (LCSCs) by forming HLCs in immunodeficient mice with as few as 100 cells. Moreover, the CD34(+) PLC subpopulation cells had an advantage over CD34(-) PLCs at initiating tumors. Three types of HLCs were generated from CD34(+) PLC: hepatocellular carcinomas (HCCs); cholangiocarcinomas (CC); and combined hepatocellular cholangiocarcinomas (CHCs). Tumors formed in mice transplanted with 12 subpopulations and 6 progeny subpopulations of CD34(+) PLC cells. Interestingly, progenies with certain surface antigens (CD133, CD44, CD90, or EPCAM) predominantly yielded HCCs. CD34(+) PLCs that also expressed OV6 and their progeny OV6(+) cells primarily produced CHC and CC. This represents the first experiment to demonstrate that the OV6(+) antigen is associated with human CHC and CC. CD34(+) PLCs that also expressed CD31 and their progeny CD31(+) cells formed CHCs. Gene expression patterns and tumor cell populations from all xenografts exhibited diverse patterns, indicating that tumor-initiating cells (TICs) with distinct antigenic profiles contribute to cancer cell heterogeneity. Therefore, we identified CD34(+) PLC cells functioning as LCSCs generating three types of HLCs. Eighteen subpopulations from one origin had the capacity independently to initiate tumors, thus functioning as TICs. This finding has broad implications for better understanding of the multistep model of tumor initiation and progression. Our finding also indicates that CD34(+) PLCs that also express OV6 or CD31 result in types of HLCs. This is the first report that PLC/PRF/5 subpopulations expressing CD34 in combination with particular antigens defines categories of

  15. Repetition Priming Effects in Proficient Mandarin-Cantonese and Cantonese-Mandarin Bidialectals: An Event-Related Potential Study.

    Science.gov (United States)

    Yi, Aiwen; Chen, Zhuoming; Chang, Yanqun; Zhou, Shu; Wu, Limei; Liu, Yaozhong; Zhang, Guoxiong

    2017-05-29

    The present study adopted a repetition priming paradigm to investigate the bidialectal (bilingual) representation of speakers with different native dialects by event-related potential (ERP) technique. Proficient Mandarin-Cantonese and Cantonese-Mandarin bidialectals participated in the study. They were required to judge whether a word was a biological word or not, when the words (target word) were represented under four types of repetition priming conditions: Mandarin (prime)-Mandarin (target), Mandarin (prime)-Cantonese (target), Cantonese (prime)-Cantonese (target) and Cantonese (prime)-Mandarin (target). Results of reaction time and accuracy primarily indicated larger repetition priming effects in Mandarin-Mandarin and Cantonese-Cantonese (within-language) conditions than that in Mandarin-Cantonese and Cantonese-Mandarin (between-language) conditions. But more importantly, P200 and N400 mean amplitudes revealed distinct repetition priming effects between two types of participants. Specifically, both P200 and N400 indicated that the repetition priming effect in Mandarin-Mandarin condition was larger than that in Cantonese-Cantonese condition for Mandarin-Cantonese participants, whereas it was opposite for Cantonese-Mandarin participants. In addition, P200 also suggested opposite patterns of repetition priming effects in between-language priming conditions for two groups of participants. The repetition priming effect in Mandarin-Cantonese condition was larger than that in Cantonese-Mandarin condition for Mandarin-Cantonese participants, while for Cantonese-Mandarin participants, it was opposite (Mandarin-Cantonese < Cantonese-Mandarin). The results implied a clear asymmetric representation of two dialects for proficient bidialectals. They were further discussed in light of native dialect and language use frequency.

  16. Ultra-wideband short-pulse radar with range accuracy for short range detection

    Science.gov (United States)

    Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

    2014-10-07

    An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

  17. Syllable frequency and word frequency effects in spoken and written word production in a non-alphabetic script

    Directory of Open Access Journals (Sweden)

    Qingfang eZhang

    2014-02-01

    Full Text Available The effects of word frequency and syllable frequency are well-established phenomena in domain such as spoken production in alphabetic languages. Chinese, as a non-alphabetic language, presents unique lexical and phonological properties in speech production. For example, the proximate unit of phonological encoding is syllable in Chinese but segments in Dutch, French or English. The present study investigated the effects of word frequency and syllable frequency, and their interaction in Chinese written and spoken production. Significant facilitatory word frequency and syllable frequency effects were observed in spoken as well as in written production. The syllable frequency effect in writing indicated that phonological properties (i.e., syllabic frequency constrain orthographic output via a lexical route, at least, in Chinese written production. However, the syllable frequency effect over repetitions was divergent in both modalities: it was significant in the former two repetitions in spoken whereas it was significant in the second repetition only in written. Due to the fragility of the syllable frequency effect in writing, we suggest that the phonological influence in handwritten production is not mandatory and universal, and it is modulated by experimental manipulations. This provides evidence for the orthographic autonomy hypothesis, rather than the phonological mediation hypothesis. The absence of an interaction between word frequency and syllable frequency showed that the syllable frequency effect is independent of the word frequency effect in spoken and written output modalities. The implications of these results on written production models are discussed.

  18. Generation of low-timing-jitter femtosecond pulse trains with 2 GHz repetition rate via external repetition rate multiplication.

    Science.gov (United States)

    Chen, Jian; Sickler, Jason W; Fendel, Peter; Ippen, Erich P; Kärtner, Franz X; Wilken, Tobias; Holzwarth, Ronald; Hänsch, Theodor W

    2008-05-01

    Generation of low-timing-jitter 150 fs pulse trains at 1560 nm with 2 GHz repetition rate is demonstrated by locking a 200 MHz fundamental polarization additive-pulse mode-locked erbium fiber laser to high-finesse external Fabry-Perot cavities. The timing jitter and relative intensity noise of the repetition-rate multiplied pulse train are investigated.

  19. The discharge mode transition and O({sup 5}p{sub 1}) production mechanism of pulsed radio frequency capacitively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X. Y.; Hu, J. T.; Liu, J. H.; Xiong, Z. L.; Liu, D. W.; Lu, X. P. [National State Key Lab of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, WuHan, HuBei 430074 (China); Shi, J. J. [College of Science, Donghua University, Shanghai 201620 (China)

    2012-07-23

    The discharge mode transition from uniform plasma across the gas gap to the {alpha} mode happens at the rising phase of the pulsed radio frequency capacitively coupled plasma (PRF CCP). This transition is attributed to the fast increasing stochastic heating at the edge of sheath. In the second stage with the stable current and voltage amplitude, the consistency between experimental and numerical spatial-temporal 777 nm emission profile suggests that He* and He{sub 2}* dominate the production of O({sup 5}p{sub 1}) through dissociation and excitation of O{sub 2}. Finally, the sterilization efficiency of PRF CCP is found to be higher than that of plasma jet.

  20. [Rehabilitation Using Repetitive Transcranial Magnetic Stimulation].

    Science.gov (United States)

    Takeuchi, Naoyuki; Izumi, Shin-Ichi

    2017-03-01

    Various novel stroke rehabilitative methods have been developed based on findings in basic science and clinical research. Recently, many reports have shown that repetitive transcranial magnetic stimulation (rTMS) improves function in stroke patients by altering the excitability of the human cortex. The interhemispheric competition model proposes that deficits in stroke patients are due to reduced output from the affected hemisphere and excessive interhemispheric inhibition from the unaffected hemisphere to the affected hemisphere. The interhemispheric competition model indicates that improvement in deficits can be achieved either by increasing the excitability of the affected hemisphere using excitatory rTMS or by decreasing the excitability of the unaffected hemisphere using inhibitory rTMS. Recovery after stroke is related to neural plasticity, which involves developing new neural connections, acquiring new functions, and compensating for impairments. Artificially modulating the neural network by rTMS may induce a more suitable environment for use-dependent plasticity and also may interfere with maladaptive neural activation, which weakens function and limits recovery. There is potential, therefore, for rTMS to be used as an adjuvant therapy for developed neurorehabilitation techniques in stroke patients.

  1. Development of a repetitive compact torus injector

    Science.gov (United States)

    Onchi, Takumi; McColl, David; Dreval, Mykola; Rohollahi, Akbar; Xiao, Chijin; Hirose, Akira; Zushi, Hideki

    2013-10-01

    A system for Repetitive Compact Torus Injection (RCTI) has been developed at the University of Saskatchewan. CTI is a promising fuelling technology to directly fuel the core region of tokamak reactors. In addition to fuelling, CTI has also the potential for (a) optimization of density profile and thus bootstrap current and (b) momentum injection. For steady-state reactor operation, RCTI is necessary. The approach to RCTI is to charge a storage capacitor bank with a large capacitance and quickly charge the CT capacitor bank through a stack of integrated-gate bipolar transistors (IGBTs). When the CT bank is fully charged, the IGBT stack will be turned off to isolate banks, and CT formation/acceleration sequence will start. After formation of each CT, the fast bank will be replenished and a new CT will be formed and accelerated. Circuits for the formation and the acceleration in University of Saskatchewan CT Injector (USCTI) have been modified. Three CT shots at 10 Hz or eight shots at 1.7 Hz have been achieved. This work has been sponsored by the CRC and NSERC, Canada.

  2. Broadband midinfrared frequency comb with tooth scanning

    Science.gov (United States)

    Lee, Kevin F.; Masłowski, P.; Mills, A.; Mohr, C.; Jiang, Jie; Schunemann, Peter G.; Fermann, M. E.

    2015-03-01

    Frequency combs are a massively parallel source of extremely accurate optical frequencies. Frequency combs generally operate at the visible or near-infrared wavelengths, but fundamental molecular vibrations occur at midinfrared wavelengths. We demonstrate an optically-referenced, broadband midinfrared frequency comb based on a doublyresonant optical parametric oscillator (OPO). By tuning the wavelength of the reference laser, the comb line frequencies are tuned as well. By scanning the reference wavelength, any frequency can be accessed, not just the frequencies of the base comb. Combined with our comb-resolving Fourier transform spectrometer, we can measure 200 wavenumber wide broadband absorption spectra with 200 kHz linewidth comb teeth. Our OPO is pumped by an amplified Tm fiber frequency comb, with phase-locked carrier envelope offset frequency, and repetition rate fixed by phase-locking a frequency comb line to a narrow linewidth diode laser at a telecom channel. The frequency comb is referenced to GPS by long-term stabilization of the repetition rate to a selected value using the temperature of the reference laser as the control. The resulting pump comb is about 3W of 100 fs pulses at 418 MHz repetition rate at 1950 nm. Part of the comb is used for supercontinuum generation for frequency stabilization, and the rest pumps an orientation-patterned gallium arsenide (OP-GaAs) crystal in a doubly-resonant optical parametric oscillator cavity, yielding collinear signal and idler beams from about 3 to 5.5 μm. We verify comb scanning by resolving the 200 MHz wide absorption lines of the entire fundamental CO vibrational manifold at 11 Torr pressure.

  3. Repetitive energy transfer from an inductive energy store

    Energy Technology Data Exchange (ETDEWEB)

    Honig, E.M.

    1984-01-01

    The theoretical and experimental results of a research program aimed at finding practical ways to transfer energy repetitively from an inductive energy store to various loads are discussed. The objectives were to investigate and develop the high power opening switches and transfer circuits needed to enable high-repetition-rate operation of such systems, including a feasibility demonstration at a current level near 10 kA and a pulse repetition rate of 1-10 kpps with a 1-ohm load. The requirements of nonlinear, time-varying loads, such as the railgun electromagnetic launcher, were also addressed. Energy storage capability is needed for proper power conditioning in systems where the duty factor of the output pulse train is low. Inductive energy storage is attractive because it has both a high energy storage density and a fast discharge capability. By producing a pulse train with a peak power of 75 MW at a pulse repetition rate of 5 kpps in a one-ohm load system, this research program was the first to demonstrate fully-controlled, high-power, high-repetition-rate operation of an inductive energy storage and transfer system with survivable switches. Success was made possible by using triggered vacuum gap switches as repetitive, current-zero opening switches and developing several new repetitive transfer circuits using the counterpulse technique.

  4. Skill learning in mirror reading: how repetition determines acquisition.

    Science.gov (United States)

    Ofen-Noy, N; Dudai, Y; Karni, A

    2003-07-01

    Practice makes perfect, but the role of repetitions in skill learning is not yet fully understood. For example, given a similar number of trials on a given task, it is debated whether repeating and non-repeating items are learned by the same neural process. When one is given training with both types of items--does one learn two separate skills, or only one? Here we show, using a mirror reading task, that practice trials with trial-unique words, and practice trials with repeated words, count towards learning to a different degree. There was no interaction between the time-course of learning repeated and unique words even within the same individuals given mixed training. While repeated words were learned faster than unique words, the repetitions-dependent gains diminished with training beyond a small number of repetitions. Moreover, the gains in performance could not be accounted for solely by the number of repetitions, as assumed by power-law models of learning; rather, the passage of time was a critical factor. Finally, our results suggest that although both repeated and new words were learned by both declarative and procedural memory mechanisms, even a single repetition of specific words could lead to the establishment of a selective differential representation in memory. The results are compatible with the notion of a repetition-sensitive process, triggered by specific repeating events. This 'repetition counter' may be a critical trigger for the effective formation of procedural as well as some type of declarative memory.

  5. Directed PCR-free engineering of highly repetitive DNA sequences

    Directory of Open Access Journals (Sweden)

    Preissler Steffen

    2011-09-01

    Full Text Available Abstract Background Highly repetitive nucleotide sequences are commonly found in nature e.g. in telomeres, microsatellite DNA, polyadenine (poly(A tails of eukaryotic messenger RNA as well as in several inherited human disorders linked to trinucleotide repeat expansions in the genome. Therefore, studying repetitive sequences is of biological, biotechnological and medical relevance. However, cloning of such repetitive DNA sequences is challenging because specific PCR-based amplification is hampered by the lack of unique primer binding sites resulting in unspecific products. Results For the PCR-free generation of repetitive DNA sequences we used antiparallel oligonucleotides flanked by restriction sites of Type IIS endonucleases. The arrangement of recognition sites allowed for stepwise and seamless elongation of repetitive sequences. This facilitated the assembly of repetitive DNA segments and open reading frames encoding polypeptides with periodic amino acid sequences of any desired length. By this strategy we cloned a series of polyglutamine encoding sequences as well as highly repetitive polyadenine tracts. Such repetitive sequences can be used for diverse biotechnological applications. As an example, the polyglutamine sequences were expressed as His6-SUMO fusion proteins in Escherichia coli cells to study their aggregation behavior in vitro. The His6-SUMO moiety enabled affinity purification of the polyglutamine proteins, increased their solubility, and allowed controlled induction of the aggregation process. We successfully purified the fusions proteins and provide an example for their applicability in filter retardation assays. Conclusion Our seamless cloning strategy is PCR-free and allows the directed and efficient generation of highly repetitive DNA sequences of defined lengths by simple standard cloning procedures.

  6. Effects of Low-frequency Repetitive Transcranial Magnetic Stimulation on Expressions of Hippocampus CA3 Region Annexin A7 in Rats after Pilocarpine-induced Seizures%低频重复经颅磁刺激的抗(癎)作用及其对癫(癎)大鼠海马CA3区膜连蛋白A7表达的影响

    Institute of Scientific and Technical Information of China (English)

    余琴; 王莉; 余巨明; 贾朝均

    2012-01-01

    目的:观察低频重复经颅磁刺激(rTMS)对大鼠(癎)性发作行为及海马CA3区膜连蛋白A7表达的影响.方法:取85只健康雄性SD大鼠,按预处理方式将其分成rTMS组(rTMS刺激+毛果芸香碱致(癎))、对照组(假刺激+毛果芸香碱致(癎))及生理盐水对照组(假刺激+生理盐水).各组大鼠经相应处理后,rTMS组和对照组(各n=30)大鼠制作氯化锂-毛果芸香碱癫(癎)持续状态(SE)模型;生理盐水对照组(n=25)则腹腔注射生理盐水.观察各组大鼠行为表现及SE潜伏期,应用免疫组化法观察膜连蛋白A7表达的动态变化(6h、24h、1周、3周、6周).结果:①rTMS组SE潜伏期为(41.37±5.45)min,与对照组(23.86±4.42)min比较明显延长(P<0.01);②海马CA3区膜连蛋白A7阳性细胞数在各时间点均为对照组最多,rTMS组次之,生理盐水对照组最少(均P<0.05).但是膜连蛋白A7的表达随时间变化的趋势rTMS组与对照组明显不同.结论:低频rTMS有一定抗(癎)作用;低频rTMS可影响大鼠海马CA3区膜连蛋白A7表达并呈现独特的动态变化特点.%Aim: To observe the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) on rat behavior and the expressions of hippocampus CA3 region annexin A7 in rats after pilocarpine-induced seizures, and explore the possible anti-epileptic mechanisms of rTMS. Methods: 85 healthy male SD rats were randomly divided into rTMS group (rTMS+pilocarpine), control group (sham stimulation+ pilocarpine), and NS control group (sham stimulation+normal saline), with 30 rats in each of rTMS group and control group, and 25 rats in NS control group. After consecutive corresponding stimulation for 2 weeks respectively, the status epilepticus rat models were established in rTMS group and control group, their behavior were observed and the latent time to status epilepticus was measured. The rats in all groups were killed in different time (6 h, 24 h, 1 week, 3 weeks, 6 weeks

  7. Detection of Human Hepatocarcinoma Cell Line PLC/PRF/5 Genome Hepatitis b Virus DNA Integration with Alu-PCR%Alu-PCR检测人肝癌细胞株PLC/PRF/5基因组中乙型肝炎病毒DNA的整合

    Institute of Scientific and Technical Information of China (English)

    邱爽; 张会英

    2015-01-01

    目的 应用Alu-PCR方法检测人肝癌细胞株PLC/PRF/5 基因组中乙型肝炎病毒( HBV) DNA的整合. 方法 提取经培养扩增的人肝癌细胞株PLC/PRF/5基因组DNA,根据Alu-PCR方法经过3轮PCR反应扩增潜在的HBV DNA和人基因组DNA整合片段. 琼脂糖凝胶电泳观察PCR扩增产物片段,切取并纯化整合阳性的电泳条带,对纯化产物进行核酸测序,得到整合片段的核苷酸序列. 结果 经琼脂糖凝胶电泳检测,用Alu-PCR方法能够从PLC/PRF/5 细胞株中扩增得到4 条HBV DNA整合序列,经测序后与比对其中3条整合序列能够定位于人染色体03p21.31、05p15.33、12q13.12~q14.1. 结论 Alu-PCR可以准确测定肝细胞中HBV DNA的整合,为研究HBV DNA在肝细胞中的整合研究提供了一个简单、经济的方法.%Objective In this research with the method of Alu -PCR we investigate the integration of hepatitis B virus ( HBV) DNA in human hepatocarcinoma cell line (PLC/PRF/5) genome DNA.Methods We at first extracted the genome DNA from PLC/PRF/5 cells, and then the potential integration fragments of HBV DNA and human genome DNA were amplified with according to the Alu -PCR after three rounds PCR .The Alu-PCR amplification products were observated with agarose gel electrophoresis , then integration positive electrophoresis bandings were chipped and purified for nucleic acid sequencing .At last he bioinformatics information was acquired by blast online.Results Through agarose gel electrophoresis after Alu -PCR amplification, we got four potential integration bindings , among which we got three integration sequences of HBV DNA in human genome DNA .These integration sequences could be individually located in the human chromosome of 03p21.31, 05p15.33, 12q13 and 12-q14.1.Conclusion With Alu-PCR we can accurately measure the integration of HBV DNA in human genome DNA , and Alu-PCR can be a a convenience and economic method in the study of HBV DNA ′s integration in human genome

  8. Cavity-enhanced field-free molecular alignment at high repetition rate

    CERN Document Server

    Benko, Craig; Allison, Thomas K; Labaye, François; Ye, Jun

    2015-01-01

    Extreme ultraviolet frequency combs are a versatile tool with applications including precision measurement, strong-field physics, and solid-state physics. Here we report on an application of extreme ultraviolet frequency combs and their driving lasers to studying strong-field effects in molecular systems. We perform field-free molecular alignment and high-order hamonic generation with aligned molecules in a gas jet at 154 MHz repetition rate using a high-powered optical frequency comb inside a femtosecond enhancement cavity. The cavity-enhanced system provides means to reach suitable intensities to study field-free molecular alignment and enhance the observable effects of the molecule-field interaction. We observe modulations of the driving field, arising from the nature of impulsive stimulated Raman scattering responsible for coherent molecular rotations. We foresee impact of this work on the study of molecule-based strong-field physics, with improved precision and a more fundamental understanding of the int...

  9. High Frequency Oscillatory Ventilation

    Directory of Open Access Journals (Sweden)

    AC Bryan

    1996-01-01

    Full Text Available High frequency oscillatory (HFO ventilation using low tidal volume and peak airway pressures is extremely efficient at eliminating carbon dioxide and raising pH in the newborn infant with acute respiratory failure. Improvement in oxygenation requires a strategy of sustained or repetitive inflations to 25 to 30 cm H2O in order to place the lung on the deflation limb of the pressure-volume curve. This strategy has also been shown to decrease the amount of secondary lung injury in animal models. Experience of the use of HFO ventilation as a rescue therapy as well as several published controlled trials have shown improved outcomes and a decrease in the use of extracorporeal membrane oxygenation when it has been used in newborns.

  10. Repetition-based Interactive Facade Modeling

    KAUST Repository

    AlHalawani, Sawsan

    2012-07-01

    Modeling and reconstruction of urban environments has gained researchers attention throughout the past few years. It spreads in a variety of directions across multiple disciplines such as image processing, computer graphics and computer vision as well as in architecture, geoscience and remote sensing. Having a virtual world of our real cities is very attractive in various directions such as entertainment, engineering, governments among many others. In this thesis, we address the problem of processing a single fa cade image to acquire useful information that can be utilized to manipulate the fa cade and generate variations of fa cade images which can be later used for buildings\\' texturing. Typical fa cade structures exhibit a rectilinear distribution where in windows and other elements are organized in a grid of horizontal and vertical repetitions of similar patterns. In the firt part of this thesis, we propose an efficient algorithm that exploits information obtained from a single image to identify the distribution grid of the dominant elements i.e. windows. This detection method is initially assisted with the user marking the dominant window followed by an automatic process for identifying its repeated instances which are used to define the structure grid. Given the distribution grid, we allow the user to interactively manipulate the fa cade by adding, deleting, resizing or repositioning the windows in order to generate new fa cade structures. Having the utility for the interactive fa cade is very valuable to create fa cade variations and generate new textures for building models. Ultimately, there is a wide range of interesting possibilities of interactions to be explored.

  11. Epithelial topography for repetitive tooth formation

    Directory of Open Access Journals (Sweden)

    Marcia Gaete

    2015-12-01

    Full Text Available During the formation of repetitive ectodermally derived organs such as mammary glands, lateral line and teeth, the tissue primordium iteratively initiates new structures. In the case of successional molar development, new teeth appear sequentially in the posterior region of the jaw from Sox2+ cells in association with the posterior aspect of a pre-existing tooth. The sequence of molar development is well known, however, the epithelial topography involved in the formation of a new tooth is unclear. Here, we have examined the morphology of the molar dental epithelium and its development at different stages in the mouse in vivo and in molar explants. Using regional lineage tracing we show that within the posterior tail of the first molar the primordium for the second and third molar are organized in a row, with the tail remaining in connection with the surface, where a furrow is observed. The morphology and Sox2 expression of the tail retains characteristics reminiscent of the earlier stages of tooth development, such that position along the A-P axes of the tail correlates with different temporal stages. Sox9, a stem/progenitor cell marker in other organs, is expressed mainly in the suprabasal epithelium complementary with Sox2 expression. This Sox2 and Sox9 expressing molar tail contains actively proliferating cells with mitosis following an apico-basal direction. Snail2, a transcription factor implicated in cell migration, is expressed at high levels in the tip of the molar tail while E-cadherin and laminin are decreased. In conclusion, our studies propose a model in which the epithelium of the molar tail can grow by posterior movement of epithelial cells followed by infolding and stratification involving a population of Sox2+/Sox9+ cells.

  12. Estimating peak response frequencies in a tidal band in the seas adjacent to China with a numerical model

    Institute of Scientific and Technical Information of China (English)

    CUI Xinmei; FANG Guohong; TENG Fei; WU Di

    2015-01-01

    A numerical method is designed to examine the response properties of real sea areas to open ocean forcing. The application of this method to modeling the China's adjacent seas shows that the Bohai Sea has a highest peak response frequency (PRF) of 1.52 d−1; the northern Yellow Sea has a PRF of 1.69 d−1; the Gyeonggi Bay has a high amplitude gain plateau in the frequency band roughly from 1.7 to 2.7 d−1; the Yellow Sea (includ-ing the Gyeonggi Bay), the East China Sea shelf and the Taiwan Strait have a common high amplitude gain band with frequencies around 1.76 to 1.78 d−1 and are shown to be a system that responds to the open ocean forcing in favor of amplifying the waves with frequencies in this band; the Beibu Gulf, the Gulf of Thailand and the South China Sea deep basin have PRFs of 0.91, 1.01 and 0.98 d−1 respectively. In addition, the East China Sea has a Poincare mode PRF of 3.91 d−1. The PRFs of the Bohai Sea, the northern Yellow Sea, the Bei-bu Gulf and the South China Sea can be explained by a classical quarter (half for the Bohai Sea) wavelength resonance theory. The results show that further investigations are needed for the response dynamics of the Yellow Sea-East China Sea-Taiwan Strait system, the East China Sea Poincare mode, the Taiwan Strait, and the Gulf of Thailand.

  13. Ultrafast, high repetition rate, ultraviolet, fiber based laser source: application towards Yb+ fast quantum-logic

    CERN Document Server

    Hussain, Mahmood Irtiza; Bentley, Christopher D B; Taylor, Richard L; Carvalho, Andre R R; Hope, Joseph J; Streed, Erik W; Lobino, Mirko; Kielpinski, David

    2016-01-01

    Trapped ions are one of the most promising approaches for the realization of a universal quantum computer. Faster quantum logic gates could dramatically improve the performance of trapped-ion quantum computers, and require the development of suitable high repetition rate pulsed lasers. Here we report on a robust frequency upconverted fiber laser based source, able to deliver 2.5 ps ultraviolet (UV) pulses at a stabilized repetition rate of 300.00000 MHz with an average power of 190 mW. The laser wavelength is resonant with the strong transition in Ytterbium (Yb+) at 369.53 nm and its repetition rate can be scaled up using high harmonic mode locking. We show that our source can produce arbitrary pulse patterns using a programmable pulse pattern generator and fast modulating components. Finally, simulations demonstrate that our laser is capable of performing resonant, temperature-insensitive, two-qubit quantum logic gates on trapped Yb$^+$ ions faster than the trap period and with fidelity above 99%.

  14. Investigation of bunch repetition rate deviations in FIR FEL driven by a magnetron-based microtron

    CERN Document Server

    Kazakevitch, Grigori M; Lee Byung Cheol; Lee, J

    2002-01-01

    The stability of the bunch repetition rate in a FIR FEL driven by a 2.8 GHz magnetron-based microtron was investigated using a heterodyne method with a low Q-factor straight-flight measuring cavity. The measuring cavity is located in the straight section of the FIR FEL injection beam line and is excited by the passage of electron bunches. The RF signal from the measuring cavity coupling loop was mixed with a precise heterodyne signal with a frequency difference of several MHz. The beat frequency was analyzed to obtain the temporal distribution of the bunch repetition rate deviation during the macro pulse of the electron beam. The time resolution and the accuracy of measurements are approximately 100 ns and a few kHz, respectively. Based on this data, we could determine the level and shape of the magnetron current and the initial frequency shift between magnetron and accelerating cavity for the FEL operation in the wavelength range 100-300 microns.

  15. Repetitive Transcranial Magnetic Stimulation for Wernicke-Korsakoff Syndrome: A Case Report.

    Science.gov (United States)

    Chung, So Won; Park, Shin Who; Seo, Young Jae; Kim, Jae-Hyung; Lee, Chan Ho; Lim, Jong Youb

    2017-02-01

    A 57-year-old man who was diagnosed with Wernicke-Korsakoff syndrome showed severe impairment of cognitive function and a craving for alcohol, even after sufficient supplementation with thiamine. After completing 10 sessions of 10 Hz repetitive transcranial magnetic stimulation (rTMS) at 100% of the resting motor threshold over the left dorsolateral prefrontal cortex, dramatic improvement in cognitive function and a reduction in craving for alcohol were noted. This is the first case report of the efficacy of a high-frequency rTMS in the treatment of Wernicke-Korsakoff syndrome.

  16. Repetitive Transcranial Magnetic Stimulation for Wernicke-Korsakoff Syndrome: A Case Report

    Science.gov (United States)

    2017-01-01

    A 57-year-old man who was diagnosed with Wernicke-Korsakoff syndrome showed severe impairment of cognitive function and a craving for alcohol, even after sufficient supplementation with thiamine. After completing 10 sessions of 10 Hz repetitive transcranial magnetic stimulation (rTMS) at 100% of the resting motor threshold over the left dorsolateral prefrontal cortex, dramatic improvement in cognitive function and a reduction in craving for alcohol were noted. This is the first case report of the efficacy of a high-frequency rTMS in the treatment of Wernicke-Korsakoff syndrome. PMID:28289650

  17. Spectrum analysis of all parameter noises in repetition-rate laser pulse train

    Institute of Scientific and Technical Information of China (English)

    Junhua Tang; Yuncai Wang

    2006-01-01

    @@ The theoretical investigation of all parameter noises in repetition-rate laser pulse train was presented. The expression of power spectrum of laser pulse trains with all parameter noises was derived, and the power spectra of pulse trains with different noise parameters were numerically simulated. By comparing the power spectra with and without pulse-width jitter, we noted that pulse-width jitter could not be neglected compared with amplitude noise and timing jitter and contributed a great amount of noise into the power spectrum under the condition that the product of pulse width and angular frequency was larger than 1.

  18. Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex; Ratner, Daniel; /SLAC; Jiao, Yi; /Beijing, Inst. High Energy Phys.

    2012-09-06

    Electron-based light sources have proven to be effective sources of high brilliance, high frequency radiation. Such sources are typically either linac-Free Electron Laser (FEL) or storage ring types. The linac-FEL type has high brilliance (because the beam is microbunched) but low repetition rate. The storage ring type has high repetition rate (rapid beam circulation) but comparatively low brilliance or coherence. We propose to explore the feasibility of a microbunched beam in a storage ring that promises high repetition rate and high brilliance. The steady-state-micro-bunch (SSMB) beam in storage ring could provide CW sources for THz, EUV, or soft X-rays. Several SSMB mechanisms have been suggested recently, and in this report, we review a number of these SSMB concepts as promising directions for high brilliance, high repetition rate light sources of the future. The trick of SSMB lies in the RF system, together with the associated synchrotron beam dynamics, of the storage ring. Considering various different RF arrangements, there could be considered a number of scenarios of the SSMB. In this report, we arrange these scenarios more or less in order of the envisioned degree of technical challenge to the RF system, and not in the chronological order of their original references. Once the stored beam is steady-state microbunched in a storage ring, it passes through a radiator repeatedly every turn (or few turns). The radiator extracts a small fraction of the beam energy as coherent radiation with a wavelength corresponding to the microbunched period of the beam. In contrast to an FEL, this radiator is not needed to generate the microbunching (as required e.g. by SASE FELs or seeded FELs), so the radiator can be comparatively simple and short.

  19. Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alex; Ratner, Daniel; /SLAC; Jiao, Yi; /Beijing, Inst. High Energy Phys.

    2012-09-06

    Electron-based light sources have proven to be effective sources of high brilliance, high frequency radiation. Such sources are typically either linac-Free Electron Laser (FEL) or storage ring types. The linac-FEL type has high brilliance (because the beam is microbunched) but low repetition rate. The storage ring type has high repetition rate (rapid beam circulation) but comparatively low brilliance or coherence. We propose to explore the feasibility of a microbunched beam in a storage ring that promises high repetition rate and high brilliance. The steady-state-micro-bunch (SSMB) beam in storage ring could provide CW sources for THz, EUV, or soft X-rays. Several SSMB mechanisms have been suggested recently, and in this report, we review a number of these SSMB concepts as promising directions for high brilliance, high repetition rate light sources of the future. The trick of SSMB lies in the RF system, together with the associated synchrotron beam dynamics, of the storage ring. Considering various different RF arrangements, there could be considered a number of scenarios of the SSMB. In this report, we arrange these scenarios more or less in order of the envisioned degree of technical challenge to the RF system, and not in the chronological order of their original references. Once the stored beam is steady-state microbunched in a storage ring, it passes through a radiator repeatedly every turn (or few turns). The radiator extracts a small fraction of the beam energy as coherent radiation with a wavelength corresponding to the microbunched period of the beam. In contrast to an FEL, this radiator is not needed to generate the microbunching (as required e.g. by SASE FELs or seeded FELs), so the radiator can be comparatively simple and short.

  20. The relationship between task repetition and language proficiency

    Directory of Open Access Journals (Sweden)

    Ahmad Mojavezi

    2014-01-01

    Full Text Available Task repetition is now considered as an important task-based implementation variable which can affect complexity, accuracy, and fluency of L2 speech. However, in order to move towards theorizing the role of task repetition in second language acquisition, it is necessary that individual variables be taken into account. The present study aimed to investigate the way task repetition correlates with language proficiency and the differential effects that task repetition might have on the complexity, accuracy, and fluency of L2 learners with different levels of proficiency. Fifty language learners of different levels of proficiency, selected from two different language centers, participated in this study. They were asked to perform an oral narrative task twice with a one-week interval. Results revealed that, compared to the participants with lower L2 proficiency, participants with higher levels of L2 proficiency produced more complex, accurate, and fluent speech on the second encounter with the same task.