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pulse wave

Melanie Graessl, Johannes Koch, Abram Calderon, Dominic Kamps, Soumya Banerjee, Tomáš Mazel, Nina Schulze, Jana Kathrin Jungkurth, Rutuja Patwardhan, Djamschid Solouk, Nico Hampe, Bernd Hoffmann, Leif Dehmelt, Perihan Nalbant
Rho GTPase-based signaling networks control cellular dynamics by coordinating protrusions and retractions in space and time. Here, we reveal a signaling network that generates pulses and propagating waves of cell contractions. These dynamic patterns emerge via self-organization from an activator-inhibitor network, in which the small GTPase Rho amplifies its activity by recruiting its activator, the guanine nucleotide exchange factor GEF-H1. Rho also inhibits itself by local recruitment of actomyosin and the associated RhoGAP Myo9b...
October 20, 2017: Journal of Cell Biology
Nathan Jeger-Madiot, Jérôme Gateau, Mathias Fink, Ros-Kiri Ing
We present a novel non-contact system for monitoring the heart rate on human subjects with clothes. Our approach is based on vibrocardiography, and measures locally skin displacements. Vibrocardiography with a laser Doppler vibrometer already allows monitoring of this vital sign, but can only be used on bare skin and requires an expensive piece of equipment. We propose here to use an airborne pulse-Doppler ultrasound system operating in the 20-60 kHz range, and comprised of an emitter focusing the ultrasound pulses on skin and a microphone recording the reflected waves...
October 17, 2017: Medical Engineering & Physics
Matthew McGarry, Pierre Nauleau, Iason Apostolakis, Elisa Konofagou
Accurate arterial stiffness measurement would improve diagnosis and monitoring for many diseases. Atherosclerotic plaques and aneurysms are expected to involve focal changes in vessel wall properties; therefore, a method to image the stiffness variation would be a valuable clinical tool. The pulse wave inverse problem (PWIP) fits unknown parameters from a computational model of arterial pulse wave propagation to ultrasound-based measurements of vessel wall displacements by minimizing the difference between the model and measured displacements...
September 27, 2017: Journal of Biomechanics
Min Kyoung Kim, Myung Sub Yi, Pyung Gul Park, Hyun Kang, Jae Sung Lee, Hwa Yong Shin
BACKGROUND: The success of stellate ganglion block (SGB) is traditionally determined on the basis of findings such as Horner's syndrome, temperature rise in the face, hyperemia of the tympanic membrane, and nasal congestion. However, decreases in vascular resistance and increases in blood flow in the arm may be more meaningful findings. To date, the effect of SGB on the regional hemodynamics of the arm has not been evaluated using pulsed-wave Doppler ultrasound. METHODS: A total of 52 patients who were to undergo orthopedic surgery of the forearm were randomly assigned to either the mepivacaine group (SGB with 5 mL of 0...
October 17, 2017: Anesthesia and Analgesia
Earric Lee, Tanjaniina Laukkanen, Setor K Kunutsor, Hassan Khan, Peter Willeit, Francesco Zaccardi, Jari A Laukkanen
Background Heat therapy has been suggested to improve cardiovascular function. However, the effects of hot sauna exposure on arterial compliance and the dynamics of blood flow and pressure have not been well documented. Thus, we investigated the short-term effects of sauna bathing on arterial stiffness and haemodynamics. Design The design was an experimental non-randomised study. Methods There were 102 asymptomatic participants (mean age, 51.9 years) who had at least one cardiovascular risk factor. Participants were exposed to a single sauna session (duration: 30 min; temperature: 73℃; humidity: 10-20%)...
January 1, 2017: European Journal of Preventive Cardiology
Jean-Philippe Haymann, Nadjib Hammoudi, Katia Stankovic Stojanovic, Frederic Galacteros, Anoosha Habibi, Virginie Avellino, Pablo Bartolucci, Yahia Benzerara, Jean-Benoit Arlet, Morad Djebbar, Emmanuel Letavernier, Gilles Grateau, Nathalie Tabibzadeh, Alexei Girshovich, Michel Chaignon, Robert Girot, Pierre Levy, Francois Lionnet
The management of sickle cell nephropathy (SCN) at an early stage is an important issue to prevent renal and cardiovascular morbidity and mortality. This study aimed to evaluate in this population, whether angiotensin converting enzyme inhibitors (ACEIs) treatment could exert a cardio-renal protection in a SCN cohort. Forty-two SCN patients (urine albumin:creatinine ratio (ACR) > 10 mg/mmol) were treated with ACEIs for 6 months, then evaluated for ACR, measured glomerular filtration rate (mGFR) together with haematological and cardiovascular parameters...
October 19, 2017: British Journal of Haematology
E Manikanta, L Vinoth Kumar, Ch Leela, P Prem Kiran
Evolution of acoustic shock wave (ASW) properties generated during nanosecond (ns) and picosecond (ps) laser-induced breakdown (LIB) of atmospheric air at different input intensities is presented. The intensity is varied by changing the focal geometry of ns and ps pulses. The ASW pressures are observed to follow the dynamic interplay between the plasma density and recombination of plasma species. The conversion of laser energy to acoustic energy has increased from loose to tight focusing conditions. The central frequencies have moved toward the lower side with increasing laser intensities for both ns-LIB (76-48 kHz) and ps-LIB (111...
August 20, 2017: Applied Optics
Yafei Cao, Dongfang Jia, Tonghui Liu, Tianxin Yang, Zhaoying Wang, Chunfeng Ge
We have experimentally demonstrated a square pulse in a passively mode-locked Yb-doped fiber ring laser operating in the dissipative soliton resonance (DSR) region based on the nonlinear polarization rotation technique. In our experiment, a 1.5-km long single-mode fiber (SMF) is inserted into the cavity to increase the cavity length. The total cavity is 1501.8 m. With increasing pump power, the pulse duration can be tuned from 209.8 ns to 812.4 ns without wave-breaking, and the maximum output single pulse energy is 42...
August 20, 2017: Applied Optics
Quanxin Na, Chunqing Gao, Qing Wang, Yixuan Zhang, Mingwei Gao, Meng Zhang, Yujia Wang
In this paper, we report the experimental realization of a high-repetition-rate single-frequency Ho-doped yttrium aluminum garnet (Ho:YAG) ring laser at 2.09 μm. Single-frequency operation of the ring laser is achieved by injection-seeding with a continuous wave (CW) Ho:YAG non-planar ring oscillator (NPRO) laser. The output energy of the ring laser is 6.24 mJ with a pulse width of 172 ns and a repetition rate of 1 kHz. The beam quality M(2)-factor is measured to be ∼1.3 at the maximum output energy...
September 1, 2017: Applied Optics
Yue Ma, Song Li, Wenhao Zhang, Zhiyu Zhang, Hui Zhou, Ma Xin
The echo width is one of the most essential parameters of waveforms, which can be used to evaluate the ranging performance of a laser altimeter or retrieve wind speeds when laser pulses illuminate on the sea surface. The classical expression of waveform widths is not suitable for a current satellite laser altimeter because only the waves on the sea with smaller wavelengths can be covered by a satellite laser altimeter due to its small footprint. A new expression is derived by dividing the broadening effect of echo widths into the wind wave with small wavelengths and the swell cause with large wavelengths...
August 1, 2017: Applied Optics
Zhengqian Luo, Runhua Yang, Tuanjie Du, Qiujun Ruan, Weiwei Li, Nan Chen
In this paper, we report the intermode beating mode-locking of a 2  μm Tm(3+)-doped fiber laser (TDFL) pumped by a 1565 nm continuous-wave multi-longitudinal-mode laser. Because strong intermode beating of the 1565 nm pump source induces the periodic modulation of 2 μm intracavity power, stable mode-locking of the TDFL is successfully established by precisely matching the 2 μm cavity frequency with the intermode-beating frequency of the 1565 nm pump source. The mode-locked laser, without requiring any specific mode-locking element, can stably emit the rectangular nanosecond pulses...
August 1, 2017: Applied Optics
Umıt Demırbas
Transition metal-doped gain media, such as Ce:LiCAF, Ti:sapphire, Cr:ZnSe, and Fe:ZnSe, possess wide gain bandwidths that could provide ultra broadly tunable laser output with the usage of adequate intracavity tuning elements. Birefringent filters (BRFs) are a low-cost and easy to use solution for tuning. However, for ultrabroad gain media, regular on-surface optic axis BRFs could not provide smooth tuning of laser wavelength in the whole emission range. Basically, regular BRFs could not accommodate a large enough free spectral range with acceptable modulation depth variation while tuning, due to their slow tuning rates...
October 1, 2017: Applied Optics
Zefeng Wang, Bo Gu, Yubin Chen, Zhixian Li, Xiaoming Xi
We report here for the first time, to the best of our knowledge, a 100-kW-peak-power, GHz-linewidth, sub-nanosecond, 1.9-μm laser source by gas stimulated Raman scattering (SRS) in hollow-core fiber. A H2-filled, anti-resonance, hollow-core fiber is pumped with a sub-nanosecond, high-peak-power, 1064-nm microchip laser, generating a 1908-nm Stokes wave by vibrational SRS of H2 molecules. A maximum peak power of about 150 kW (average power 55 mW, pulse energy 55 μJ) is achieved with a 1.4-m fiber length and only 3 bar H2 pressure...
September 20, 2017: Applied Optics
Ryu Niigaki, Yuichiro Kida, Totaro Imasaka
In 2001, a concept was proposed to generate mode-locked ultrashort laser pulses with a repetition rate in excess of 10 THz [Phys. Rev. Lett.87, 223901 (2001)PRLTAO0031-900710.1103/PhysRevLett.87.223901], which has not been demonstrated so far. In the present research, the concept is experimentally demonstrated using a dispersion-compensated high-finesse cavity filled with hydrogen gas. Second-order intensity autocorrelation is used for distinguishing two cases with and without mode-locking as well as for characterization of the temporal profile...
September 20, 2017: Applied Optics
Wenqi Zhang, Yijie Shen, Yuan Meng, Mali Gong
An 888 nm pumped quasi-single-crystal-fiber (quasi-SCF) acousto-optic Q-switched Nd:YVO4 laser is experimentally demonstrated for the first time, where two closely jointed crystals with different side surface styles serve as a long thin medium to improve the pump absorption and alleviate thermal load. In continuous-wave operation, the highest output power can reach 38.7 W with corresponding optical-optical efficiency of 0.492. In Q-switched operation, the optical-optical efficiency increases from 0.347 to 0...
September 20, 2017: Applied Optics
Qingchao Su, Tianshu Wang, Jing Zhang, Wanzhuo Ma, Peng Liu, Yuwei Su, Qingsong Jia
We study a passively mode-locked square-wave pulse (SWP) fiber laser with a nonlinear amplifying loop mirror in the cavity. The net dispersion of the cavity is about 0.68  ps(2) and the SWP mode-locked fiber laser can be realized. The peak power of the SWP hardly varies and the pulse duration gets expanded with the increasing pump power. SWPs breaking in the low nonlinear cavity can be observed and the stable dual SWP can be achieved in the experiment. When the total pump power stays at 800 mW, the interval of dual pulses is 41 ns...
June 10, 2017: Applied Optics
Jinglong Lan, Xiaoxu Huang, Xiaofeng Guan, Bin Xu, Huiying Xu, Zhiping Cai, Xiaodong Xu, Dongzhen Li, Jun Xu
We report on diode-pumped Nd(3+)-doped calcium barium niobate ferroelectric crystal (Nd:CBN-28) lasers at 1.06 and 1.34 μm. The maximum output power of the 1.06 μm laser reaches 0.69 W in the continuous-wave regime, which is believed to be the highest output power with Nd:CBN-28 crystal to date. Using a chopper to modulate the pump, the highest output power further improves to 0.77 W. Passively Q-switched laser operation at 1.06 μm, using a Cr:YAG saturable absorber, is realized with a maximum average output power of 89 mW, a pulse width of 220 ns, and a pulse energy 10...
May 10, 2017: Applied Optics
Gary L Pierce
PURPOSE OF REVIEW: Habitual aerobic exercise is associated with lower aortic stiffness, as measured by carotid-femoral pulse wave velocity (CFPWV), in middle-aged/older adults without hypertension, but beneficial effects of aerobic exercise on CFPWV in hypertension remain contraversial. Therefore, the focus of this review is to discuss the evidence for and against the beneficial effects of aerobic exercise on aortic stiffness in middle-aged and older adults with hypertension, possible limitations in these studies, and highlight novel directions for future research...
October 18, 2017: Current Hypertension Reports
Yi-Chao Lu, Ping Lyu, Hong-Yan Zhu, Dong-Xu Xu, Sulaiman Tahir, Hai-Feng Zhang, Fang Zhou, Wen-Ming Yao, Lei Gong, Yan-Li Zhou, Rong Yang, Yan-Hui Sheng, Dong-Jie Xu, Xiang-Qing Kong, Jan A Staessen, Xin-Li Li
BACKGROUND: Brachial-ankle pulse wave velocity (baPWV) can be easily measured in an observer-independent way, but lacks robust population-based validation in terms of fatal combined with nonfatal outcomes. METHOD: To address this issue, we studied 4251 Chinese randomly recruited Gaoyou County (54.1% women; mean age, 52.1). RESULTS: In the whole study population, mean values were 102.4 mmHg for mean arterial pressure (MAP), 51.1 mmHg for pulse pressure, and 14...
October 16, 2017: Journal of Hypertension
Frank Lloyd Dini, Erberto Carluccio, Fabrizio Montecucco, Gian Marco Rosa, Paolo Fontanive
BACKGROUND: Chronic heart failure (HF) is a relevant and growing public health problem. Although the prognosis has recently improved, it remains a lethal disease, with a mortality that equals or exceeds that of many malignancies. Furthermore, chronic HF is costly, representing a large and growing drain on healthcare resources. METHODS: This narrative review is based on the material searched for and obtained via PubMed up to May 2017. The search terms we used were: "heart failure, echocardiography, natriuretic peptides" in combination with "treatment, biomarkers, guidelines"...
October 16, 2017: European Journal of Clinical Investigation
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