Journal articles: 'Pulse blanking'

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Murakami, Tomohiro, Ming Yang, Hiroshi Kishi, Sigeki Mori, Masahiro Ohkawa, and Eiichi Fujino. "Reducing Blanking Vibration with Active Vibration Control Using a Servo Press." Key Engineering Materials 716 (October 2016): 510–20. http://dx.doi.org/10.4028/www.scientific.net/kem.716.510.

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Blanking noise and blanking vibration are causes of pollution. At the same time, blanking vibration disturbs the high precision of a press work product, and shortens the life expectancy of the press machine and the press die. Recently, the use of a servo press has been developed to improve these problems, using low speed blanking and pulse vibration banking. However, these methods lengthen the blanking time, so it is necessary to control the servo press properly in the case of blanking. In this study, we describe a principle for the reduction of blanking vibration when using a servo press, and we propose an active vibration control method for the reduction of blanking vibration. We used a crank servo press of 450kN in an experiment, which has a pulse motion of 10Hz. We conducted a simulation and an experiment of blanking using an active vibration control method, which we named “counter pulse blanking.” We confirmed that counter pulse blanking is effective in reducing vibration as a result of the simulation and the experiment.

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Keshkar, Miziya, Raja Muthalagu, and Abdul Rajak. "ROAD Statistics-Based Noise Detection for DME Mitigation in LDACS." Applied Sciences 12, no. 8 (April 8, 2022): 3774. http://dx.doi.org/10.3390/app12083774.

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Interference mitigation in L-band Digital Aeronautic Communication Systems (LDACS) from legacy users is extremely important as any error in data retrieval of aeronautic communication can adversely affect flight safety. This paper proposes an LDACS receiver prototype which uses rank-ordered absolute differences (ROAD) statistics to detect the distance measuring equipment (DME) interference. The detected DME interference is reduced in the next stage by pulse blanking. The performance of the proposed ROAD pulse blanking method (ROAD PB) is compared with the existing interference mitigation methods which use the amplitude of the received signal for the detection of DME interference. In depth analysis of the obtained results affirms that the proposed ROAD value-based interference detection excels amplitude-based detection. For an SNR value of 0 dB, the proposed method of detection could achieve a 3% increase in terms of accuracy with a reduction of 4% in false alarms. With the advantage of ROAD statistics detection, the proposed ROAD PB could achieve an SNR saving of 2.7, 1.1, 0.7, 0.25 and 0.2 dBs at BER 10−1 in comparison with pulse blanking, Genie-aided estimation enhanced pulse peak attenuator (GAEPPA), GAE enhanced pulse peak limiter (GAEPPL), optimum Bayesien estimator enhanced pulse peak attenuator (OBEPPA) and OBE enhanced pulse peak limiter (OBEPPL). The comparative results show that the proposed ROAD pulse blanking outperformed the other techniques for the optimum threshold value of the operation.

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O'Connor, Brian J., H. John Yack, and Scott C. White. "Reducing Errors in Kinetic Calculations: improved Synchronization of Video and Ground Reaction Force Records." Journal of Applied Biomechanics 11, no. 2 (May 1995): 216–23. http://dx.doi.org/10.1123/jab.11.2.216.

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A strategy is presented for temporally aligning ground reaction force and kinematic data. Alignment of these data requires marking both the force and video records at a common event. The strategy uses the information content of the video signal, which is A/D converted along with the ground reaction force analog signals, to accomplish this alignment in time. The vertical blanking pulses in the video signal, which define the start of each video field, can be readily identified, provided the correct A/D sampling rate is selected. Knowledge of the position of these vertical blanking pulses relative to the synchronization pulse makes it possible to precisely align the video and analog data in time. Choosing an A/D sampling rate of 598 Hz would enable video and analog data to be synchronized to within 1/1,196 s. Minimizing temporal alignment error results in greater accuracy and .reliability in calculations used to determine joint kinetics.

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Bostanjoglo, O., F. Heinricht, and F. Wünsch. "Performance of A Laser-Pulsed Thermal Electron Gun." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 124–25. http://dx.doi.org/10.1017/s0424820100179373.

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High-speed electron microscopy strongly demands a high-brightness electron gun in order to increase the number of image forming electrons. A few years ago, a laser-pulsed high-brightness electron gun was introduced. Fig.1 shows the experimental set-up, A standard triode system was supplemented with a Nd:YAG laser, focussing optics and a modified anode, which incorporates the laser deflection mirror. The frequency doubled laser pulse (τ =5 ns, λ = 532 nm) is focused through a window onto the tip of the tungsten hairpin emitter. The laser treated area (≈ 100 μm diameter) is heated well above the melting point, which results in a strong thermal electron emission. Due to rapid heat-up and fast cool-down of the tungsten surface short electron pulses with a duration of 20 ns and a maximum current of 20 mA at 80 kV are emitted. A destruction of the tungsten wire is avoided, too. Laser energies used for the generation of electron pulses are in the range of 100 μJ. Due to these minor modification, the DC operation of the electron gun is not disabled, which allows a convenient adjustment in the DC mode and then switching into the pulsed operation mode. Fig.2 shows a typical electron pulse emitted by the gun. Shorter electron pulses up to 5 ns can be generated by a beam blanking unit.

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Anyaegbu, Esther, Gary Brodin, John Cooper, Enrique Aguado, and Said Boussakta. "An Integrated Pulsed Interference Mitigation for GNSS Receivers." Journal of Navigation 61, no. 2 (March 25, 2008): 239–55. http://dx.doi.org/10.1017/s0373463307004572.

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The E5/L5 frequency band for the new Global Navigation Satellite System (GNSS) signals is crowded with aeronautical pulsed emitters. This results in severe degradation of the performance of GNSS receivers. This paper describes a novel technique for estimating and suppressing time-varying pulsed interference signals such as the Distance Measuring Equipment (DME)/Tactical Air Navigation (TACAN) signals generated by these pulsed emitters. The proposed technique involves the integration of the time-based pulse blanker and the wavelet-based interference mitigation technique. Aviation is the key application considered although many other applications such as transport management and navigation, environmental monitoring, and telecommunications would benefit. A performance assessment of the new technique is carried out by determining the degradation of the carrier-to-noise ratio (CNR) at the output of the correlator. The performance of the new technique is compared with the traditional time domain pulse blanking approach. The results show that the proposed technique performs better than both the time domain pulse blanker and the wavelet-based interference mitigation algorithm. Hence, the integrated pulse mitigation approach can be employed to provide an enhanced degree of interference detection and suppression.

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MURAKAMI, Tomohiro, Ming YANG, Hiroshi KISHI, Masahiro OHKAWA, Mitsuhiro SAKURAI, and Eiichi FUJINO. "Reducing Blanking Vibration with Counter Pulse Using Servo Press Slide." Journal of the Japan Society for Technology of Plasticity 58, no. 675 (2017): 311–16. http://dx.doi.org/10.9773/sosei.58.311.

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Guo, Yong Feng, Ji Cheng Bai, Li Qing Li, and Cheng Jun Li. "Study on Surface Performance of Carbon-Aluminum-Carbon Electrode of Super-Capacitor in Dry WEDM." Key Engineering Materials 375-376 (March 2008): 401–5. http://dx.doi.org/10.4028/www.scientific.net/kem.375-376.401.

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Super-capacitors are new equipments for energy storage，and they have wide application in practice. At present, blanking is used to machining the electrodes of super-capacitor; however, the disadvantages of the method are burrs, electrode collapse. A new method processing electrode of super-capacitor, wire electrical discharge machining in gas (dry WEDM), were presented in this paper, and the electrode surface morphologies were studied utilizing scan electron microscope (SEM). First, the surface morphologies comparison studies of super-capacitor electrodes processed with different method, such as shearing, blanking and dry WEDM etc., were performed, and research results show that the super-capacitor electrode surfaces machined by dry WEDM achieve flat machining surface, and electrode edges do not collapse. Further surface morphology analysis was carried out based on different pulse durations and air pressure, and analysis results indicate that better machining surface can be achieved when suitable pulse duration and gas pressure are selected. Finally, surface energy spectrum analysis of the super-capacitor electrode processed by dry WEDM is performed, and the analysis result show that alumina are formed on the middle of electrode, aluminum foil, which is favored to the performance of super-capacitor.

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Niamsuwan, Noppasin, Joel T. Johnson, and Steven W. Ellingson. "Examination of a simple pulse-blanking technique for radio frequency interference mitigation." Radio Science 40, no. 5 (June 8, 2005): n/a. http://dx.doi.org/10.1029/2004rs003155.

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9

Vuong, Duc-Phuc, Dang-Khanh Le, Khac-Khiem Nguyen, and Binh Van Nguyen. "Correlation Receiver With Nonlinearity Blanking for DCSK Systems Under Pulse Jamming Attack." IEEE Access 7 (2019): 25037–45. http://dx.doi.org/10.1109/access.2019.2900259.

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Laffite, S., S. D. Baton, P. Combis, J. Clerouin, M. Koenig, V. Recoules, C. Rousseaux, and L. Videau. "Velocity Interferometer blanking due to preheating in a double pulse planar experiment." Physics of Plasmas 21, no. 8 (August 2014): 082705. http://dx.doi.org/10.1063/1.4892184.

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11

Rai, S. S. "Transient electromagnetic response of a thin conducting plate embedded in conducting host rock." GEOPHYSICS 50, no. 8 (August 1985): 1342–49. http://dx.doi.org/10.1190/1.1442005.

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The transient response of a thin, rectangular conducting plate in a conductive host medium is presented for a horizontal‐loop electromagnetic (EM) system considering both a step and pulse EM method (PEM) excitation. For a shallow plate‐like conductor, the current‐gathering effect is preceded by a blanking effect. However, for deeper plates, current gathering was not observed. The effect of increasing plate depth, the ratio of the time constant of the plate to that of the host, and the plate time constant on the temporal characteristics of blanking and current gathering are investigated. The onset time for current gathering is independent of the plate time constant and is essentially a property of the host medium. At later observations (⩾5 ms) the decay of the plate in the host resembles the decay of the plate in free air. An interpretation scheme is proposed to determine plate parameters for Crone PEM measurements using the responses in two relatively late time channels.

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12

Wu, Di, Jing Ji, Jing Li, Dongming Zhao, and Wei Chen. "Design and Performance Analysis of Optimal Pulse Blanking Threshold with Non-Uniform Quantization." Journal of Computational and Theoretical Nanoscience 13, no. 6 (June 1, 2016): 3815–23. http://dx.doi.org/10.1166/jctn.2016.5215.

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13

Borio, Daniele, and Eduardo Cano. "Optimal Global Navigation Satellite System pulse blanking in the presence of signal quantisation." IET Signal Processing 7, no. 5 (July 2013): 400–410. http://dx.doi.org/10.1049/iet-spr.2012.0199.

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14

Keshkar, Miziya, Raja Muthalagu, Abdul Rajak, and Libin K. Mathew. "GAE and OBE Enhanced Interference Mitigation Techniques in LDACS." Aerospace 9, no. 1 (January 17, 2022): 45. http://dx.doi.org/10.3390/aerospace9010045.

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Interference mitigation in L-band digital aeronautic communication systems from legacy users is vital due to stringent safety requirements and steady-state increase in air traffic. This paper proposes an L-band digital aeronautic communication systems receiver prototype that employs nonlinear operations to reduce the interference from the prime interference contributor distance measuring equipment. The knowledge of genie-aided estimator and optimum Bayesian estimator is utilized to propose improved and low complexity nonlinear devices, such as a genie-aided estimator enhanced pulse peak attenuator, genie-aided estimator enhanced pulse peak limiter, joint genie-aided estimator enhanced pulse peak attenuator, joint genie-aided estimator enhanced pulse peak limiter, optimum Bayesian estimator enhanced pulse peak attenuator, optimum Bayesian estimator enhanced pulse peak limiter, joint optimum Bayesian estimator enhanced pulse peak attenuator and joint optimum Bayesian estimator enhanced pulse peak limiter. The performance of the proposed methods is compared with the classical pulse blanking in terms of the received bit error rate for different signal-to-noise ratios. The proposed genie-aided estimator enhanced methods exhibited SNR saving in the range of 2 to 2.5 dB at a bit error rate of 10−1. At the same BER, the proposed optimum Bayesian estimator enhanced methods achieved SNR saving in the range of 2.5 to 3 dB.

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15

Ma, P., X. Tang, S. Lou, K. Liu, and G. Ou. "Code Tracking Performance Analysis of GNSS Receivers with Blanking Model under Periodic Pulse Interference." Radioengineering 30, no. 1 (April 15, 2021): 184–95. http://dx.doi.org/10.13164/re.2021.0184.

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Raja, N. K. L., K. J. Rangra, and M. Singh. "Online exposure dose correction during electron beam pattern delineation by blanking pulse width modulation." Microelectronic Engineering 11, no. 1-4 (April 1990): 371–74. http://dx.doi.org/10.1016/0167-9317(90)90133-e.

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Korada, Santarao, Munmun Bhaumik, and CHILAMKURTI LAKSHMI VENKATA RANGA SOBHANACHALA VARA PRASAD. "SURFACE IMPROVEMENT OF AISI D3 STEEL EMPLOYING SiC BLENDED DIELECTRIC IN ELECTRIC DIE SINKING PROCESS." International Journal of Modern Manufacturing Technologies 14, no. 1 (June 20, 2022): 75–80. http://dx.doi.org/10.54684/ijmmt.2022.14.1.75.

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AISI D3 die steel is extensively used in long-run dies for blanking, forming, deep drawing, and thread rolling. Among all the non-traditional machining processes, the Electric Die Sinking Process (EDSP) is mostly employed to manufacture these long-run dies. The EDSP method produces a surface of high quality, which impacts product performance significantly. The surface roughness of AISI D3 die steel is examined in relation to a number of parameters, including peak current, pulse-on duration, gap voltage, and powder concentration. Copper is selected as the tool. Orthogonal array concept coined by Taguchi has been deployed to execute the experiments. It is clearly understood from the results that powder concentration has a key impact on machined surface quality by lessening the generated cracks and enhancing the surface finish by 20%. Further, peak current has more impact on the performance characteristics than pulse-on time and the gap voltage.

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18

Yan, Kong, Chen Xian-Feng, and Xia Yu-Xing. "Optimized Second Harmonic Generation of Femtosecond Pulse by Phase-Blanking Effect in Aperiodically Optical Superlattice." Chinese Physics Letters 25, no. 4 (April 2008): 1297–300. http://dx.doi.org/10.1088/0256-307x/25/4/037.

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Liu, Haitao, Wenqiang Zhao, and Dongxia Li. "The Capacity Performance of OFDM Systems with Nonlinear Pulse Blanking in Frequency Selective Fading Channels." Wireless Personal Communications 104, no. 1 (October 11, 2018): 91–110. http://dx.doi.org/10.1007/s11277-018-6010-0.

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20

Marigodov, V. K., and E. F. Baburov. "Increase of noise-immunity of the system of spaced radio reception by blanking of pulse interferences." Radioelectronics and Communications Systems 55, no. 8 (August 2012): 381–84. http://dx.doi.org/10.3103/s0735272712080067.

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Sharma, Husandeep, Khushdeep Goyal, and Sunil Kumar. "Performance evaluation of cryogenically treated wires during wire electric discharge machining of AISI D3 die tool steel under different cutting environments." Multidiscipline Modeling in Materials and Structures 15, no. 6 (November 4, 2019): 1318–36. http://dx.doi.org/10.1108/mmms-04-2019-0078.

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Purpose Tool steel (AISI D3) is a preferred material for industrial usage. Some of the typical applications of D3 tool steel are blanking and forming dies, forming rolls, press tools and punches bushes. It is used under conditions where high resistance to wear or to abrasion is required and also for resistance to heavy pressure rather than to sudden shock is desirable. It is a high carbon and high chromium steel. Therefore, wire electric discharge machining (WEDM) is used to machine this tool steel. The paper aims to discuss these issues. Design/methodology/approach The present experimental investigation evaluates the influence of cryogenically treated wires on material removal rate (MRR) and surface roughness (SR) for machining of AISI D3 steel using the WEDM process. Two important process responses MRR and SR have been studied as a function of four different control parameters, namely pulse width, time between two pulses, wire mechanical tension and wire feed rate. Findings It was found that pulse width was the most significant parameter which affects the MRR and SR. Better surface finish was obtained with cryogenically treated zinc coated wire than brass wire. Originality/value The review of the literature indicates that there is limited published work on the effect of machining parameters in WEDM in cryogenic treated wires. Therefore, in this research work, it was decided to evaluate the effect of cryogenically treated wires on WEDM.

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Nayak, Ipsita, and Jaydev Rana. "Multi-response optimization in wire electrical discharge machining (WEDM) of D2 steel using utility approach." Manufacturing Review 8 (2021): 16. http://dx.doi.org/10.1051/mfreview/2021014.

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Wire electrical discharge machining (WEDM) is a popular non-conventional machining process used particularly for making extrusion dies, blanking punches, and tools especially requiring tight dimensional tolerances. Because of the process limitation, the rate of cutting and maintenance of close dimensional tolerance is a challenging task. Given the above facts, the present work has been focused on achieving the maximum possible cutting rate (VC) maintaining good dimensional accuracy and corner radius (RC). In the present research work, a multi-response optimization method (i.e. Taguchi based Utility approach) has been used to obtain an optimum set of input parameters such as pulse on time (TON), pulse off time (TOFF), servo voltage (SV), and wire feed rate (WF) resulting into a best overall cutting performance. Analysis of variance (ANOVA) is also used to find out the significant effect of each machining parameter on the cutting performance. The analysis reported in this paper will be helpful for industry personnel to select the best set of process parameters for achieving a good result without the use of any software or statistical analysis.

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Schönhense, G., K. Medjanik, O. Fedchenko, A. Zymaková, S. Chernov, D. Kutnyakhov, D. Vasilyev, et al. "Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter." Journal of Synchrotron Radiation 28, no. 6 (November 1, 2021): 1891–908. http://dx.doi.org/10.1107/s1600577521010511.

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The small time gaps of synchrotron radiation in conventional multi-bunch mode (100–500 MHz) or laser-based sources with high pulse rate (∼80 MHz) are prohibitive for time-of-flight (ToF) based photoelectron spectroscopy. Detectors with time resolution in the 100 ps range yield only 20–100 resolved time slices within the small time gap. Here we present two techniques of implementing efficient ToF recording at sources with high repetition rate. A fast electron-optical beam blanking unit with GHz bandwidth, integrated in a photoelectron momentum microscope, allows electron-optical `pulse-picking' with any desired repetition period. Aberration-free momentum distributions have been recorded at reduced pulse periods of 5 MHz (at MAX II) and 1.25 MHz (at BESSY II). The approach is compared with two alternative solutions: a bandpass pre-filter (here a hemispherical analyzer) or a parasitic four-bunch island-orbit pulse train, coexisting with the multi-bunch pattern on the main orbit. Chopping in the time domain or bandpass pre-selection in the energy domain can both enable efficient ToF spectroscopy and photoelectron momentum microscopy at 100–500 MHz synchrotrons, highly repetitive lasers or cavity-enhanced high-harmonic sources. The high photon flux of a UV-laser (80 MHz, <1 meV bandwidth) facilitates momentum microscopy with an energy resolution of 4.2 meV and an analyzed region-of-interest (ROI) down to <800 nm. In this novel approach to `sub-µm-ARPES' the ROI is defined by a small field aperture in an intermediate Gaussian image, regardless of the size of the photon spot.

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Xu-Friedman, M. A., and C. D. Hopkins. "Central mechanisms of temporal analysis in the knollenorgan pathway of mormyrid electric fish." Journal of Experimental Biology 202, no. 10 (May 15, 1999): 1311–18. http://dx.doi.org/10.1242/jeb.202.10.1311.

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Mormyrid electric fish communicate using pulse-type electric organ discharges (EODs). The fine temporal structure of the waveforms of EODs varies widely throughout the 200 or more species of mormyrids. These signals carry information about the species, the sex and even the individual identity of the signaller. Behavioral experiments have shown that some species of fish are capable of using this information. Of the four known types of electroreceptors in mormyrid fish, the knollenorgan electroreceptor is the one most likely to be involved in the detection of conspecific EOD signals. Here, we review some recent advances in understanding how the central knollenorgan pathway might be analyzing the temporal structure of the EOD waveform. Fine temporal analysis appears to take place in the nucleus exterolateralis pars anterior (ELa), where tightly phase-locked inputs from the hindbrain drive a direct, excitatory input through a long axonal delay line and also drive an indirect, inhibitory input with negligible delay through the ELa large cell. These two inputs converge on ELa small cells, where they are hypothesized to interact in a ‘delay-line/blanking’ model. This initial temporal analysis is further refined in the nucleus exterolateralis pars posterior, where units tuned to ranges of pulse durations have been identified physiologically.

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Musumeci, Luciano, Jaron Samson, and Fabio Dovis. "Performance assessment of pulse blanking mitigation in presence of multiple Distance Measuring Equipment/Tactical Air Navigation interference on Global Navigation Satellite Systems signals." IET Radar, Sonar & Navigation 8, no. 6 (July 2014): 647–57. http://dx.doi.org/10.1049/iet-rsn.2013.0198.

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Hohneck, Anna, Christina Reyser, Kirsten Merx, Simone Weingärtner, Athanasios Mavratzas, Gerhard Schumacher, Christoph Linhuber, Wolf-Karsten Hofmann, Iris Burkholder, and Ralf-Dieter Hofheinz. "Differential Effects of Sound Intervention and Rest on Cardiovascular Parameters in Cancer Patients: A Randomized Cross-over Trial." Integrative Cancer Therapies 20 (January 2021): 153473542199523. http://dx.doi.org/10.1177/1534735421995239.

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Background: Music therapy or sound interventions were shown to confer beneficial effects in patients with cancer for instance in terms of pain or fear relief and improvement of other patient reported outcomes. Cardiovascular parameters, especially heart rate variability (HRV) were found to have prognostic implications in cancer patients. In this trial we aimed to investigate the effects of a sound intervention on cardiovascular parameters compared to rest in patients with cancer. Methods and results: Using a randomized cross-over design, 52 patients (male 13, female 39) with cancer were recruited to receive both a 15-minute sound intervention and a 15-minute rest intervention within 4 weeks with at least a one-week blanking period. Cardiovascular parameters (among others HRV, aortic pulse wave velocity [PWV], augmentation index [Aix], aortic blood pressure [BP], heart rate [HR]) were assessed immediately before (pre) and after (post) the intervention had taken place. HRV (Root mean square of successive RR interval differences [RMSSD, ms]) significantly increased, during sound intervention (median RMSSD pre 24 [range 5-112] vs post 22 [range 9-141], P = .03). Likewise, median PWV, as a direct marker of arterial stiffness, was significantly reduced by sound intervention ([m/s] pre 8.5 [range 5.6-19.6] vs post 8.3 [range 5.6-15.6], P = .04). For both parameters no statistically significant change during rest was observed. HR was lowered by both, rest ( P < .0001) and sound intervention ( P = .02), with a more pronounced effect by rest. A significant increase in systolic aortic blood pressure was shown by rest ([mmHg] median 101 [range 78-150] vs post median 103 [range 71-152], P = .04) but not during sound intervention ( P = .59), while rest intervention led to a decrease in resistance index (pre median 33 [range 13-92] vs post median 32 [11-84], P = .02). Conclusion: In comparison with rest, a single sound intervention in patients with cancer improved cardiovascular parameters commonly associated with increased stress levels. Studies with longer follow-up and multiple interventions are warranted. Trial Registration: ISRCTN registry 70947363.

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Nieuwland, Andre K. "GRI Ranking Based on Cross-Rate Interference in Loran-C." Journal of Navigation 48, no. 1 (January 1995): 136–52. http://dx.doi.org/10.1017/s037346330001256x.

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This paper starts with a brief overview of cross-rate interference (CRI) and methods developed in the past for estimating the CRI between two Group Repetition Intervals (GRIS). It presents an algorithm for fast calculation of the loss of pulses due to blanking in dual-rate stations. These stations broadcast on the GRIS of two chains but, if pulses of both chains overlap, one GRI is not transmitted at that instant. Furthermore, it will discuss the impact of this blanking on the use of Loran-C signals for transmitting data. A strategy is given for selecting GRIS, based on the presented theory. The paper is based on papers presented at the 1993 WGA technical symposium and the 1993 INA conference.

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Kodama, Kazuki, and Daisuke Ueda. "The Effect of Introducing Optical Blanking on GaN Epitaxy Using Pulsed Laser Deposition Technology." physica status solidi (a) 217, no. 3 (September 9, 2019): 1900517. http://dx.doi.org/10.1002/pssa.201900517.

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Puls, Joachim, Tamara Repolust, Tadziu L. Hoffmann, Alexander Jokuthy, and Roberto O. J. Venero. "Advances in radiatively driven wind models." Symposium - International Astronomical Union 212 (2003): 61–69. http://dx.doi.org/10.1017/s0074180900211650.

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We report on a re-analysis of the Galactic O-type star sample presented by Puls et al. (1996) by means of non-LTE model atmospheres including line-blocking and line-blanketing. In particular, we concentrate on the question concerning the dependence of the wind-momentum luminosity relation (WLR) on luminosity class. Owing to the line-blanketing, the derived effective temperatures become significantly lower when compared to previous results, whereas the so-called ‘modified wind-momentum rates’ remain roughly at their former values. Therefore, we obtain a new WLR for O-type stars. By comparing these ‘observational’ results with new theoretical predictions and simulations, we conclude that the Hα forming region for objects with Hα in emission might be considerably clumped and thus a larger mass-loss rate than actually present is mimicked. We suggest that the previously found dependence of the WLR on luminosity class is an artefact.

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Kuji, Chieko, Masayoshi Mizutani, Kana Takenaka, Keita Shimada, Toyohiko J. Konno, Hitoshi Soyama, and Tsunemoto Kuriyagawa. "Effect of local heating by ultrashort pulsed laser on Fe–Si–B–Cr amorphous alloys and its influence on blanking machinability." Precision Engineering 81 (May 2023): 135–44. http://dx.doi.org/10.1016/j.precisioneng.2023.02.007.

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Blanken, A., C. J. Van der Laken, and M. Nurmohamed. "AB1081 BLOOD PRESSURE, BMI AND SEX AFFECT OPTICAL SPECTRAL TRANSMISSION IMAGING MEASUREMENTS OF THE HANDS." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1829.1–1829. http://dx.doi.org/10.1136/annrheumdis-2020-eular.4718.

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Background:Optical spectral transmission imaging (OST) is a new imaging method designed to measure inflammation in the hands of rheumatoid arthritis (RA) patients. The device uses a pressure cuff to occlude venous blood flow, resulting in an increased blood pool in the hands of the patient. In inflamed joints transmission of light through this blood pool is altered due to higher blood content, lower oxygenation and stronger hemodynamics at the location of inflammation [1]. However, altered hemodynamics not related to inflammatory arthritis might also influence OST measurements.Objectives:In this study we investigated whether hemodynamic and other cardiovascular parameters affect OST measurements in healthy participants.Methods:OST measurement was done in 37 healthy participants using the HandScan device from Hemics, the Netherlands. Carotid intima media thickness (IMT), pulse wave velocity (PWV) and augmentation index (AIx) were measured with ultrasound and SphygmoCor tonometry. Age, sex, diastolic and systolic blood pressure, pulse, hypertension (defined as systolic blood pressure >140 mmHg or diastolic blood pressure > 90 mmHg or antihypertensive treatment), total cholesterol, HDL, LDL, total/HDL cholesterol ratio, body mass index (BMI), European SCORE risk assessment, smoking status, cardiovascular history and medication use were collected during the same visit. Associations were investigated using univariate linear regression and multivariate regression adjusting for age and sex.Results:Participants were 53 ± 8 years old and 65% was female. Systolic and diastolic blood pressure was 129 ± 19 mmHg and 80 ± 9 mmHg respectively and 22% used antihypertensive treatment, 8% an anticoagulant and 11% a statin. In total 38% had hypertension and 8% had a history of cardiovascular disease.Mean OST value was 12.69 ± 3.47 and all values were between 5.00 and 20.78. Cardiovascular and hemodynamic parameters that were associated with higher OST measurement were: hypertension (14.18 ± 1.12 versus 11.79 ± 0.69), systolic and diastole blood pressure, BMI and European SCORE (table 1). Also, male sex was associated with a higher OST with and without adjustment for age (15.05 ± 1.04 versus 11.41 ± 0.62 for females).Table 1.Cardiovascular and hemodynamic parameters associated with higher OST measurementUnivariateAdjusted for age and sexB95%CIpB95%CIpHypertension (y/n)2.390.124.670.042.410.374.450.02Systolic blood pressure0.080.030.140.0050.070.020.120.01Diastolic blood pressure0.200.080.320.0010.190.090.290.001BMI0.24-0.010.480.060.260.050.470.02Sex (male/female)*3.671.565.780.0013.541.295.790.003European SCORE**1.240.092.390.04n/a*Adjusted for age only, **Not adjusted because age and sex are included in the European SCOREOther parameters (age, cholesterol, pulse, IMT, having carotid plaque, PWV, AI, cardiovascular history, smoking status and statin, antihypertensive drug and/or anticoagulant use) were not associated with the OST measurement (p>0.13, data not shown)Excluding the 5 (14%) participants with hand osteoarthritis showed comparable results, except for BMI and hypertension. BMI was also significantly associated with OST in the univariate analysis (B 0.24, 95%CI 0.01-0.47, p=0.039), while hypertension lost its statistical significance (uni B 1.74, 95%CI -0.69-4.17, p=0.15; multi B 1.44, 95%CI -0.61-3.48, p=0.16).Conclusion:High blood pressure, BMI, male sex and European SCORE are associated with increased OST values in healthy participants. This indicates that differences in OST measurements of RA patients might not only reflect inflammatory burden but is also dependent on sex, blood pressure and body composition. This should be taken into account when using optical spectral transmission imaging for the assessment of inflammation in RA patients.References:[1]Meier et al. 2012 J Biomed Opt 17(8):081420Disclosure of Interests:Annelies Blanken: None declared, C.J. van der Laken: None declared, Michael Nurmohamed Grant/research support from: Not related to this research, Consultant of: Not related to this research, Speakers bureau: Not related to this research

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Blanken, A., R. Agca, C. D. Popa, and M. Nurmohamed. "AB0238 SERUM LEVELS OF E-SELECTIN AND IL-8 DECREASE AFTER 6 MONTHS OF ANTI-INFLAMMATORY THERAPY AND MIRROR FAVORABLE VASCULAR CHANGES IN RHEUMATOID ARTHRITIS." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1419. http://dx.doi.org/10.1136/annrheumdis-2020-eular.2293.

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Background:Accelerated atherosclerosis is a systemic manifestation of rheumatoid arthritis (RA). E-selectin, VCAM-1, MCP1/CCL2 and IL-8/CXCL8 are involved in leukocyte migration through endothelial cells in both atherosclerosis and RA [1]. Therefore, these endothelial function markers might reflect endothelial function and systemic inflammation in RA. If so, such a marker could be used to assess cardiovascular risk in RA patients.Objectives:The aim of this study was to investigate the effect of 6 months of anti-inflammatory treatment on RA serum levels of endothelial function markers and whether these serum levels are related to prognostic imaging markers for atherosclerosis.Methods:E-selectin, VCAM-1, MCP1 and IL-8 serum levels were determined at baseline and after 6 months of therapy with MTX monotherapy or in combination with adalimumab for 40 RA patients and 19 osteoarthritis (OA) controls using commercial ELISA kits. Prognostic imaging markers for atherosclerosis were pulse wave velocity (PWV) and augmentation index (AIx) as measured with SphygmoCor tonometry. Parametric analyses were used for E-selectin, VCAM-1 and MCP1 and non-parametric or parametric analyses after log transformation for IL-8.Results:Baseline VCAM-1 and IL-8 were significantly higher for RA patients than OA controls with and without adjustment for age and sex or traditional risk factors (table 1).Table 1.Comparison between RA and OA serum levels of endothelial function markers at baselineOARACrude analysisAdjusted age sexAdjusted traditional risk factors*Mean ±SD or median (IQR)Mean ±SD or median (IQR)Difference OA and RA (95%CI)pDifference OA and RA (95%CI)pDifference OA and RA (95%CI)PE-selectin (ng/ml)29 ±1532 ±173 (-6-12)0.493 (-6-12)0.533 (-7-13)0.54VCAM-1 (ng/ml)786 ±102897 ±200110 (13-208)0.03103 (4-202)0.04110 (2-218)0.05MCP1 (pg/ml)248 ±248316 ±16568 (-15-150)0.1171 (-10-152)0.0949 (-41-138)0.28IL-8 (pg/ml)15 (10-25)37 (17-117)n/a0.01n/a0.01n/a0.02* Age, hypertension, bmi and pack yearsAfter 6 months of anti-inflammatory therapy, E-selectin and IL-8 serum levels significantly decreased (table 2). This decrease was especially present in the RA patients with good EULAR-DAS28 response to the medication and not in patients with no/moderate response (E-selectin: -7, 95%CI -13- -2, p=0.007 versus -0.1, 95%CI -3-2, p=0.925; IL-8: -2, p=0.033 versus -1, p=0.267).Table 2.Endothelial function markers difference after 6 months of therapy in RA patientsDifference (95%CI)p-valueE-selectin (ng/ml)-4 (-7-1)0.010VCAM-1 (ng/ml)+10 (-56-77)0.753MCP1 (pg/ml)-14 (-34-62)0.557IL-8 (pg/ml)-11 (n/a)0.014Furthermore, in the RA patients we found a significant correlation between the difference in PWV after 6 months and the difference in E-selectin (Pearson r=0.450, p=0.018) and IL-8 (Spearman r=0.401, p=0.038). All other possible correlations of the endothelial function markers with PWV and AIx were not significant (data not shown).Conclusion:Serum levels of E-selectin and IL-8 decreased after 6 months of anti-inflammatory therapy, and both correlated with the PWV changes. This is the first study investigating both serologic as well as imaging markers of endothelial function and atherosclerosis in RA patients undergoing anti-inflammatory therapy. Our study suggests that E-selectin and IL-8 circulatory levels may reflect the best both systemic inflammation as well as endothelial function in RA, and might be therefore useful in the future as markers of cardiovascular risk in these patients.References:[1]Haringman et al. Targeting cellular adhesion molecules, chemokines and chemokine receptors in rheumatoid arthritis. Expert Opin Emerg Drugs, 2005. 10(2): p. 299-310.Disclosure of Interests:Annelies Blanken: None declared, Rabia Agca: None declared, C.D. Popa: None declared, Michael Nurmohamed Grant/research support from: Not related to this research, Consultant of: Not related to this research, Speakers bureau: Not related to this research

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Liu, Haitao, Zhisheng Yin, and Xuejun Zhang. "Symbol Error Performance Analysis of OFDM Receiver with Pulse Blanking over Frequency Selective Fading Channel." Journal of Communications, 2016. http://dx.doi.org/10.12720/jcm.11.3.325-332.

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Liu, Haitao, Zhisheng Yin, Min Jia, and Xuejun Zhang. "SER analysis of the MRC-OFDM receiver with pulse blanking over frequency selective fading channel." EURASIP Journal on Wireless Communications and Networking 2016, no. 1 (May 18, 2016). http://dx.doi.org/10.1186/s13638-016-0615-3.

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Piemontese, G. P., L. Bartoli, G. Statuto, A. Angeletti, G. Massaro, C. Martignani, M. Ziacchi, and M. Biffi. "Optimal his bundle pacing programming in patients with permanent atrial fibrillation." European Heart Journal 42, Supplement_1 (October 1, 2021). http://dx.doi.org/10.1093/eurheartj/ehab724.0680.

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Abstract Background Interest in permanent His bundle pacing (HBP) as a means of both preventing pacing-induced cardiomyopathy and providing physiological resynchronization by normalization of His-Purkinje activation is constantly growing. Current devices are not specifically designed for HBP, which gives rise to programming challenges. Purpose To evaluate the critical troubleshooting HBP options in patients with permanent atrial fibrillation (AF) and variable degree of atrio-ventricular block (AVB) who receive HBP through a lead connected to the atrial port, and an additional ventricular “backup”. Methods Between December 2018 and March 2021, 136 consecutive patients with indication for pacing underwent HBP. Among these, 24 had permanent AF with documented symptomatic pauses. Seven of them received a dual-chamber device which was used to place a backup right ventricle (RV) lead; in this scenario, the His lead is implanted in the right atrial (RA) port, the RV lead in the RV port. Depending on the presence of an additional left ventricle (LV) lead, either a dual-chamber and a CRT device can be used. Results In this context, the events marked as atrial sensed (As) or paced (Ap) are indeed ventricular, so that sensing is more complex. A clinical scenario is atrial activity oversensed on the His channel (As) leading to RV dyssynchronous pacing in the ventricular safety pacing (VSP) window. A second one is intrinsic QRS undersensing causing inappropriate His pacing with possible delivery of the RV pulse depending on capture of the His pulse. The interplay of intrinsic ventricular activity (rate, signal amplitude and slew rate on both the His and the ventricular channel) and of the HV interval may be of key importance to troubleshoot As-Vp (atrial sensed – ventricular paced) [Fig. 1A] as well as Vs-Ab (ventricular sensed – atrial blanking period) sequences [Fig. 1B]. Changing sensitivity and sensing configuration may help or fail to fix these issues depending on the abovementioned aspects, making it mandatory to check that the paced AV delay is appropriately set as to avoid inappropriate RV pacing on the T wave of an undersensed intrinsic event at the His channel. DVI(R) mode programming may indeed prove safer than DDD(R) in the setting of preserved intrinsic activity or in the event of intermittent His capture loss. Paced AV delay should be programmed slightly longer than H-V+QRS duration to avoid unnecessary RV pacing with pseudo-fusion (too short) and possibly R/T events (too long). Stability of H-V interval and of QRS duration must be verified at each device follow-up by decremental His pacing to ensure consistent sensitivity of the ventricular signal beyond stable His capture, that may be challenged by infra-hisian block. Conclusions Owing to the absence of HBP-specific devices, HBP shall be made safe and effective by careful troubleshooting, consisting of sensitivity setting, paced AV interval and mode programming. Funding Acknowledgement Type of funding sources: None. Different sensitivity settings for HBP

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Verma, Atul, David E. Haines, Lucas V. Boersma, Nitesh Sood, Andrea Natale, Francis E. Marchlinski, Hugh Calkins, et al. "Pulsed Field Ablation for the Treatment of Atrial Fibrillation: PULSED AF Pivotal Trial." Circulation, March 6, 2023. http://dx.doi.org/10.1161/circulationaha.123.063988.

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BACKGROUND: Pulsed field ablation uses electrical pulses to cause nonthermal irreversible electroporation and induce cardiac cell death. Pulsed field ablation may have effectiveness comparable to traditional catheter ablation while preventing thermally mediated complications. METHODS: The PULSED AF pivotal study (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF) was a prospective, global, multicenter, nonrandomized, paired single-arm study in which patients with paroxysmal (n=150) or persistent (n=150) symptomatic atrial fibrillation (AF) refractory to class I or III antiarrhythmic drugs were treated with pulsed field ablation. All patients were monitored for 1 year using weekly and symptomatic transtelephonic monitoring; 3-, 6-, and 12-month ECGs; and 6- and 12-month 24-hour Holter monitoring. The primary effectiveness end point was freedom from a composite of acute procedural failure, arrhythmia recurrence, or antiarrhythmic escalation through 12 months, excluding a 3-month blanking period to allow recovery from the procedure. The primary safety end point was freedom from a composite of serious procedure- and device-related adverse events. Kaplan-Meier methods were used to evaluate the primary end points. RESULTS: Pulsed field ablation was shown to be effective at 1 year in 66.2% (95% CI, 57.9 to 73.2) of patients with paroxysmal AF and 55.1% (95% CI, 46.7 to 62.7) of patients with persistent AF. The primary safety end point occurred in 1 patient (0.7%; 95% CI, 0.1 to 4.6) in both the paroxysmal and persistent AF cohorts. CONCLUSIONS: PULSED AF demonstrated a low rate of primary safety adverse events (0.7%) and provided effectiveness consistent with established ablation technologies using a novel irreversible electroporation energy to treat patients with AF.

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Kueffer, T., J. Seiler, A. Madaffari, A. Muehl, R. Stettler, B. Asatryan, A. Haeberlin, et al. "Pulsed field ablation of atrial fibrillation: recurrence rate after first pulmonary vein isolation and first insights into durability at redo procedures." EP Europace 24, Supplement_1 (May 18, 2022). http://dx.doi.org/10.1093/europace/euac053.148.

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Abstract Funding Acknowledgements Type of funding sources: None. Background Pulsed field ablation (PFA) is newly available for pulmonary vein isolation (PVI) and combines the benefits of high procedural efficacy and safety. Independent data on the recurrence-rate of atrial fibrillation (AF) after PVI and on PVI durability during redo procedures are scarce. Purpose We report data on the recurrence rate of AF after first PVI using PFA and first insights into findings of PVI durability during redo procedures. Methods Consecutive AF patients undergoing a first PFA PVI at our center between May 2021 and August 2021 were included. PVI was verified by 3D-electroanatomical mapping (3D-EAM), and additional PFA lesions were applied when necessary until all PV were isolated. Seven-day Holter ECGs were performed at 3 and 6 months after ablation. After a blanking period of 3 months, episodes of AF/AT lasting more than 30 seconds were considered as AF-recurrence. Results 41 Patients, median age 69 (interquartile range 62-73) years, 24% female, 56% persistent AF, underwent first PVI by PFA. All PVs were successfully isolated using a multipolar PFA catheter. Median total procedure time including 3D-EAM was 104 (85-121) min. Total fluoroscopy time and dose were 26 (19-30) min and 671 (323-1248) Gym2. Acute complications occurred in 1 (2.4%) patient (cardiac tamponade requiring drainage). Early recurrence of AF during the blanking period occurred in 1 (2.4%) patient. Median follow-up time was 107 (91-152) days. Recurrence of AF after the blanking period was detected in 5 (12%) patients, 1 (6%) in paroxysmal AF and 4 (17%) in persistent AF patients, respectively. Redo procedures in 3 (7.3%) patients with AF recurrence confirmed durable isolation of 12/12 (100%) pulmonary veins and showed no evidence of PFA lesion regression. Conclusion AF recurrence rates after PVI by means of PFA are low. Durable isolation of 12/12 pulmonary veins (100%) and no evidence of PFA lesion regression was observed during redo procedures in patients with AF recurrence.

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Tanashkin, A. S., A. V. Karpova, A. Y. Potekhin, Y. A. Shibanov, and D. A. Zyuzin. "XMM-Newton observations of PSR J0554+3107: pulsing thermal emission from a cooling high-mass neutron star." Monthly Notices of the Royal Astronomical Society, August 2, 2022. http://dx.doi.org/10.1093/mnras/stac2164.

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Abstract XMM-Newton observations of the middle-aged radio-quiet γ-ray pulsar J0554+3107 allowed us, for the first time, firmly identify it in X-rays by detection of pulsations with the pulsar period. In the 0.2–2 keV band, the pulse profile shows two peaks separated by about a half of the rotation phase with the pulsed fraction of 25 ± 6 per cent. The profile and spectrum in this band can be mainly described by thermal emission from the neutron star with the hydrogen atmosphere, dipole magnetic field of ∼1013 G and non-uniform surface temperature. Non-thermal emission from the pulsar magnetosphere is marginally detected at higher photon energies. The spectral fit with the atmosphere+power law model implies that J0554+3107 is a rather heavy and cool neutron star with the mass of 1.6–2.1 M⊙, the radius of ≈13 km and the redshifted effective temperature of ≈50 eV. The spectrum shows an absorption line of unknown nature at ≈350 eV. Given the extinction–distance relation, the pulsar is located at ≈2 kpc and has the redshifted bolometric thermal luminosity of ≈2 × 1032 erg s−1. We discuss cooling scenarios for J0554+3107 considering plausible equations of state of super-dense matter inside the star, different compositions of the heat-blanketing envelope and various ages.

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Winkelmann, SJ, MD Lemoine, T. Wuerger, R. Schleberger, L. Rottner, L. Dinshaw, JM Moser, et al. "Safety of pulsed-field ablation in patients with cardiac implantable electronic devices. A single-center pilot study." EP Europace 24, Supplement_1 (May 18, 2022). http://dx.doi.org/10.1093/europace/euac053.234.

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Abstract Funding Acknowledgements Type of funding sources: None. Introduction Pulsed-field ablation (PFA) is a novel energy source to perform pulmonary vein isolation (PVI) in patients with atrial fibrillation or cavo-tricuspid isthmus ablation (CTI) in patients with atrial flutter. Whether strong electrical fields generated by PFA could change the function and integrity of cardiac implantable electronic devices (CIED) is not known. Aim To assess the function and integrity of implanted devices before and after pulsed-field ablation. Methods This study included consecutive patients with CIED undergoing PFA at a large single center. Real-time CIED electrograms were recorded during PFA applications. CIED were interrogated before and after PFA assessing function (threshold, sensing), integrity (impedance), and arrhythmia episodes. Results We performed PFA in six patients (age 69±12 years, 1/6 female, left atrial diameter was 44±3 mm, left-ventricular ejection fraction 40±14%) for PVI in five patients with atrial fibrillation and CTI ablation in one patient with atrial flutter. All patients had CIEDs (one cardiac resynchronization device, two implantable cardioverter-defibrillators, three two-chamber pacemakers). Each patient undergoing PVI received 32 PFA applications of 2.5 s. (4x basket configuration and 4x flower configuration at each pulmonary vein), amounting to a total ablation time of 80 s and resulting in complete PVI in all five patients. For CTI ablation we applied 8 PFA applications of 2.5 s (20 s total ablation time) resulting in CTI blockade. Real-time intracardiac electrograms (iEGM) during PFA applications revealed sensing of single PFA application impulses in three patients and blanking of the iEGM in three patients. Postinterventional device testing revealed no changes in impedance, stimulation threshold or sensing. No leads were dislocated or damaged. No other device malfunctions occurred during the procedure, as well as no other major periprocedural complications occurred. Conclusion The function and integrity of pacemakers and defibrillators is not affected by PFA in our patient sample. Larger series are needed to confirm the apparent safety of PFA in patients with CIED.

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Wahedi, R., S. Willems, M. Jularic, J. Hartmann, B. Schaeffer, Ö. Akbulak-Stegli, C. Eickholt, et al. "Safety and efficacy of catheter ablation for atrial fibrillation in the very elderly." European Heart Journal 43, Supplement_2 (October 1, 2022). http://dx.doi.org/10.1093/eurheartj/ehac544.459.

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Abstract Background The incidence and prevalence of atrial fibrillation (AF) increases with age. With an ageing general population, a 2.3-fold rise in AF prevalence is expected. Catheter ablation has emerged as an effective treatment option for rhythm control therapy. However, very elderly patients (≥80 years old) have been excluded in landmark clinical trials. Current data regarding the safety and efficacy of catheter ablation in the very elderly is therefore sparse. Purpose Due to the growing demand to manage AF in an increasingly ageing population, we investigated the safety and efficacy of catheter ablation in this particular patient population. Methods Patients with symptomatic paroxysmal, persistent and long-standing persistent AF aged ≥80 years undergoing catheter ablation, including first and re-ablation procedures in a single centre, were analysed retrospectively. Catheter ablation involved pulmonary vein isolation (PVI) using radiofrequency, cryoballoon and pulsed field ablation as energy sources. Re-ablation procedures included re-PVI and consecutive atrial tachycardia ablation including atrial lines and/or ablation of complex fractionated atrial electrograms (CFAE) in persistent AF. Endpoints included acute procedural success (complete isolation of pulmonary veins and/or non-inducibility in the case of atrial tachycardia), major complications and early arrhythmia-recurrence. Results A total of eighty-eight patients (mean age 83.1±1.9 years, mean CHA2DS2-VASc-Score 4.4±1, mean left ventricular ejection fraction 56.7±7%, direct oral anticoagulation 92.1%, vitamin-K antagonists 7.9%) were included from January 2021 to October 2021. Fifty cases (56.8%) involved PVI as an index procedure (radiofrequency 58%, n=29/50, cryoballoon 36%, n=18/50, pulsed field ablation 6%, n=3/50). Thirty-eight procedures (43.2%) involved re-ablation procedures (Re-PVI 60.5%, n=23/38, linear lesions 65.8%, n=25/38, atrial tachycardia ablation 26.3%, n=10/38 and ablation of CFAE 15.8%, n=6/38). Acute procedural success was achieved in 87/88 patients (98.9%). Major complications included stroke (n=1/88, 1.1%), pericardial tamponade (n=1/88, 1.1%) and bradycardia with subsequent pacemaker implantation (n=3/88, 3.4%). No further major complications were documented. In 13/88 patients (14.8%) early arrhythmia-recurrence occurred (38.5%, n=5/13 after the index procedure and 61.5%, n=8/13 after re-ablation) during the 90-day blanking period. Conclusions Catheter ablation for atrial fibrillation in the very elderly shows favourable acute success and low complication rates. Long term success of catheter ablation and superiority to rate control in this patient population is unknown and requires investigation in the future. Funding Acknowledgement Type of funding sources: None.

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Farinha, J. M., M. Fonseca, L. Parreira, A. F. Esteves, A. Pinheiro, J. Ferreira, R. Coelho, et al. "Left atrial stiffness measured by echocardiography is a stronger predictor of atrial fibrillation recurrence after radiofrequency catheter ablation than left atrial volume." European Heart Journal 42, Supplement_1 (October 1, 2021). http://dx.doi.org/10.1093/eurheartj/ehab724.0510.

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Abstract Introduction Left atrial volume (LAV) is an accepted predictor of atrial fibrillation (AF) recurrence after radiofrequency catheter ablation, stronger than AF duration. Objective The aim of this study was to assess the value of left atrial stiffness (LAS) index as a new parameter evaluated by echocardiography to the prediction of AF recurrence after radiofrequency catheter ablation. Methods We retrospectively studied consecutive patients with paroxysmal or persistent AF submitted to radiofrequency catheter ablation at our institution between 2017 and 2019. We used transthoracic echocardiography to measure the LAV indexed to body surface area and the LAS index, defined as the ratio between the mitral E/e' (obtained with pulsed Doppler at the tip of the mitral leaflets – E, and tissue Doppler imaging at the mitral annulus – e') and the left atrial strain during the reservoir phase (obtained by speckle tracking echocardiography) [LAS index = (E/e') / LA reservoir strain]. The left ventricular ejection fraction (LVEF) was also evaluated. Patients with poor quality echocardiographic images were excluded. We compared 2 groups of patients, according to the recurrence of AF after the blanking period. We analysed the clinical characteristics and echocardiographic findings. The effect of clinical and echocardiography parameters on AF recurrence was evaluated by univariate and multivariate Cox Regression analysis. Results We studied 33 patients, 27 with paroxysmal AF and 6 with persistent AF. Baseline patients' characteristics are presented in Table 1. During a mean follow-up time of 17.9±10.4 months, 7 patients (21%) had AF recurrence, and none died. Patients with AF recurrence had a higher LAS index. After adjusting for confounding variables, only LAS index and LAV were independently associated with AF recurrence (Table 2). Every one unit increase in LAS index was associated with an 11-fold increased risk of AF recurrence (HR 10.86, 95% CI 1.38–85.56; p=0.024), while every one unit increase in LAV index was only associated with a 6% increased risk of AF recurrence (HR 1.06, 95% CI 1.01–1.11, p=0.010). Conclusion LAS index evaluated by echocardiography was a much stronger predictor of AF recurrence after radiofrequency catheter ablation than left atrial volume. Funding Acknowledgement Type of funding sources: None.

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Álvaro, J. Javier, Susan C. Johnson, Sandra M. Barr, Sören Jensen, Teodoro Palacios, Deanne van Rooyen, and Chris E. White. "Unconformity-bounded rift sequences in Terreneuvian‒Miaolingian strata of the Caledonian Highlands, Atlantic Canada." GSA Bulletin, August 30, 2022. http://dx.doi.org/10.1130/b36402.1.

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The Cambrian syn-rift strata preserved in western Avalonia provide a distinctive example of how unconformity-bounded sequences are diachronous throughout proximal to marginal rift branches. Terreneuvian‒Miaolingian third-order sequences of the Caledonian Highlands, New Brunswick, Canada, reflect a complex interplay among syn-rift tectonic events, denudation pulses, and sea-level fluctuations. Unconformably overlying the early, rift-related volcanosedimentary Coldbrook Group (ca. 560‒550 Ma), the Ratcliffe Brook, Glen Falls, Hanford Brook, and Forest Hills Formations can be subdivided into two transgressive systems tract (TST)‒highstand systems tract (HST) sequences (each ∼10 m.y.) and an incomplete TST sequence that are separated by stratigraphic gaps. They reflect uplift and tilting events affecting the basement, transgressive and drowning surfaces, and condensed sections. Arid to semi-arid climatic episodes are supported by the excellent preservation of mafic to felsic volcanic clasts in non-marine breccias and conglomerates, which are derived from the Ediacaran basement, and the local precipitation of marine gypsum through the evaporation of pore fluids. Early Miaolingian episodes of microbial/shelly carbonate production preserved precipitates of coeval evaporite (gypsum pseudomorphs after drusy mosaics of calcite) and ikaite (glendonitic, star-shaped aggregates and crusts). Both minerals, traditionally considered to be indicators of contrasting climate conditions, potentially co-occur in temperate-water substrates recording high rates of microbial activity. The early rift phases preserved in the western Avalonian rift transect comprise stepwise uplift and unroofing of rift shoulders, which are related to diachronous, angular discordances and paraconformities bounded by syntectonic slope-apron deposits. Facies homogenization was attained during Miaolingian times as a result of generalized flooding, sealing of paleotopographies, and blanketing with monotonous offshore-dominant shales.

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Anderson, Scott W., and Kristin L. Jaeger. "Coarse sediment dynamics in a large glaciated river system: Holocene history and storage dynamics dictate contemporary climate sensitivity." GSA Bulletin, August 21, 2020. http://dx.doi.org/10.1130/b35530.1.

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The gravel-bedded White River drains a 1279 km2 basin in Washington State, with lowlands sculpted by continental glaciation and headwaters on an actively glaciated stratovolcano. Chronic aggradation along an alluvial fan near the river’s mouth has progressively reduced flood conveyance. In order to better understand how forecasted climate change may influence coarse sediment delivery and aggradation rates in this lowland depositional setting, we assessed the contemporary delivery and routing of coarse sediment through the watershed; this assessment was based on a rich set of topographic, sedimentologic, and hydrologic data from the past century, with a focus on repeat high-resolution topographic surveys from the past decade. We found that most of the lower river’s contemporary bed-load flux originates from persistent erosion of alluvial deposits in the lower watershed. This erosion is a response to a drop in local base level caused by a major avulsion across the fan in 1906 and then augmented by subsequent dredging. The 1906 avulsion and modern disequilibrium valley profiles reflect landscape conditioning by continental glaciation and a massive mid-Holocene lahar. In the proglacial headwaters, infrequent large sediment pulses have accomplished most of the observed coarse sediment export, with exported material blanketing downstream valley floors; during typical floods, transported bed material is largely sourced from erosion of these valley floor deposits. Throughout the watershed, we observe decadal-scale coarse sediment dynamics strongly related to the filling or emptying of valley-scale sediment storage over 102−104 yr time scales, often in response to major disturbances that either emplace large deposits or influence their redistribution. Paraglacial responses in large watersheds are suggested to be inherently complicated and punctuated as a result of internal landform interactions and stochastic/threshold-dependent events. We argue, in combination, that Holocene disturbance, storage dynamics, and human flow modification make coarse sediment fluxes in the lower White River relatively insensitive to decadal climate variability. Results highlight the degree to which river sensitivity to contemporary disturbance, climatic or otherwise, may be contingent on local and idiosyncratic watershed histories, underscoring the need to unpack those histories while demonstrating the utility of watershed-scale high-resolution topography toward that end.

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Journal articles on the topic 'Pulse blanking'

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