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Pulse transit time

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https://www.readbyqxmd.com/read/29167479/femtosecond-to-picosecond-transient-effects-in-wse-2-observed-by-pump-probe-angle-resolved-photoemission-spectroscopy
#1
Ro-Ya Liu, Yu Ogawa, Peng Chen, Kenichi Ozawa, Takeshi Suzuki, Masaru Okada, Takashi Someya, Yukiaki Ishida, Kozo Okazaki, Shik Shin, Tai-Chang Chiang, Iwao Matsuda
Time-dependent responses of materials to an ultrashort optical pulse carry valuable information about the electronic and lattice dynamics; this research area has been widely studied on novel two-dimensional materials such as graphene, transition metal dichalcogenides (TMDs) and topological insulators (TIs). We report herein a time-resolved and angle-resolved photoemission spectroscopy (TRARPES) study of WSe2, a layered semiconductor of interest for valley electronics. The results for below-gap optical pumping reveal energy-gain and -loss Floquet replica valence bands that appear instantaneously in concert with the pump pulse...
November 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29159698/analysis-of-biosignals-during-immersion-in-computer-games
#2
Mina Yeo, Seokbeen Lim, Gilwon Yoon
The number of computer game users is increasing as computers and various IT devices in connection with the Internet are commonplace in all ages. In this research, in order to find the relevance of behavioral activity and its associated biosignal, biosignal changes before and after as well as during computer games were measured and analyzed for 31 subjects. For this purpose, a device to measure electrocardiogram, photoplethysmogram and skin temperature was developed such that the effect of motion artifacts could be minimized...
November 17, 2017: Journal of Medical Systems
https://www.readbyqxmd.com/read/29138423/the-photocycle-of-orange-carotenoid-protein-conceals-distinct-intermediates-and-asynchronous-changes-in-the-carotenoid-and-protein-components
#3
E G Maksimov, N N Sluchanko, Y B Slonimskiy, E A Slutskaya, A V Stepanov, A M Argentova-Stevens, E A Shirshin, G V Tsoraev, K E Klementiev, O V Slatinskaya, E P Lukashev, T Friedrich, V Z Paschenko, A B Rubin
The 35-kDa Orange Carotenoid Protein (OCP) is responsible for photoprotection in cyanobacteria. It acts as a light intensity sensor and efficient quencher of phycobilisome excitation. Photoactivation triggers large-scale conformational rearrangements to convert OCP from the orange OCP(O) state to the red active signaling state, OCP(R), as demonstrated by various structural methods. Such rearrangements imply a complete, yet reversible separation of structural domains and translocation of the carotenoid. Recently, dynamic crystallography of OCP(O) suggested the existence of photocycle intermediates with small-scale rearrangements that may trigger further transitions...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29124548/development-of-an-experimental-and-digital-cardiovascular-arterial-model-for-transient-hemodynamic-and-postural-change-studies-a-preliminary-framework-analysis
#4
Rodward L Hewlin, John P Kizito
The ultimate goal of the present work is to aid in the development of tools to assist in the treatment of cardiovascular disease. Gaining an understanding of hemodynamic parameters for medical implants allow clinicians to have some patient-specific proposals for intervention planning. In the present work an experimental and digital computational fluid dynamics (CFD) arterial model consisting of a number of major arteries (aorta, carotid bifurcation, cranial, femoral, jejunal, and subclavian arteries) were fabricated to study: (1) the effects of local hemodynamics (flow parameters) on global hemodynamics (2) the effects of transition from bedrest to upright position (postural change) on hemodynamics, and (3) diffusion of dye (medical drug diffusion simulation) in the arterial system via experimental and numerical techniques...
November 9, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/29120347/cuff-less-blood-pressure-measurement-from-dual-channel-photoplethysmographic-signals-via-peripheral-pulse-transit-time-with-singular-spectrum-analysis
#5
Yang Wang, Zhiwen Liu, Shaodong Ma
This paper proposes an unobtrusive blood pressure (BP) measurement system design with motion artifact (MA) compensation strategy as a potential surrogate to the traditional cuff-based sphygmomanometer for self-monitoring in less restricted environment. Approach: A dual-channel photoplethysmographic signal acquisition system is designed and implemented for the cuff-less BP measurement based on peripheral pulse transit time (PPTT) acquired from the forearm and wrist. Comprised of motion decision, singular spectrum analysis, PPTT calculation and BP measurement, a novel approach is proposed to realize BP measurement with suppressing MA interference...
November 9, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/29115323/conformational-structures-of-the-tetrahydrofuran-cation-determined-using-one-photon-mass-analyzed-threshold-ionization-spectroscopy
#6
Sung Man Park, Yu Ran Lee, Do Won Kang, Hong Lae Kim, Chan Ho Kwon
One-photon vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy was used to characterize the essential conformations of tetrahydrofuran (THF) and thus determine the stereochemistry of the furanose ring constituting the backbones of DNA and RNA. Since the VUV-MATI spectrum of THF exactly corresponds to the vibrational spectrum of the gas-phase THF cation, the above cation was detected using time-of-flight mass spectrometry featuring the delayed pulsed-field ionization of the target in high Rydberg states by scanning the wavelength of the VUV pulse across the region of the vibrational spectrum...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29110473/cycloreversion-reaction-of-a-diarylethene-derivative-at-higher-excited-states-attained-by-two-color-two-photon-femtosecond-pulsed-excitation
#7
Hikaru Sotome, Tatsuhiro Nagasaka, Kanako Une, Soichiro Morikawa, Tetsuro Katayama, Seiya Kobatake, Masahiro Irie, Hiroshi Miyasaka
Abstract  Two-color two-pulse femtosecond pulsed excitation was applied to the elucidation of the dynamics and mechanism of cycloreversion reaction of a diarylethene derivative in the higher excited states. Transient absorption spectroscopy under one-photon visible excitation revealed that the 1B state produced by the excitation undergoes the internal conversion into the 2A state with a time constant of 200 fs. Geometrical rearrangement of the 2A state takes place concomitantly with the vibrational cooling with a time constant of 3 ps...
November 6, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29092172/comprehensive-study-of-solid-pharmaceutical-tablets-in-visible-near-infrared-nir-and-longwave-infrared-lwir-spectral-regions-using-a-rapid-simultaneous-ultraviolet-visible-nir-uvn-lwir-laser-induced-breakdown-spectroscopy-linear-arrays-detection-system-and
#8
Clayton S C Yang, Feng Jin, Siva R Swaminathan, Sita Patel, Evan D Ramer, Sudhir B Trivedi, Ei E Brown, Uwe Hommerich, Alan C Samuels
This is the first report of a simultaneous ultraviolet/visible/NIR and longwave infrared laser-induced breakdown spectroscopy (UVN + LWIR LIBS) measurement. In our attempt to study the feasibility of combining the newly developed rapid LWIR LIBS linear array detection system to existing rapid analytical techniques for a wide range of chemical analysis applications, two different solid pharmaceutical tablets, Tylenol arthritis pain and Bufferin, were studied using both a recently designed simultaneous UVN + LWIR LIBS detection system and a fast AOTF NIR (1200 to 2200 nm) spectrometer...
October 30, 2017: Optics Express
https://www.readbyqxmd.com/read/29083165/ultrafast-intersystem-crossing-in-acetylacetone-via-femtosecond-x-ray-transient-absorption-at-the-carbon-k-edge
#9
Aditi Bhattacherjee, Chaitanya Das Pemmaraju, Kirsten Schnorr, Andrew R Attar, Stephen R Leone
Molecular triplet states constitute a crucial gateway in the photochemical reactions of organic molecules by serving as a reservoir for the excess electronic energy. Here, we report the remarkable sensitivity of soft X-ray transient absorption spectroscopy for following the intricate electronic structure changes accompanying the non-adiabatic transition of an excited molecule from the singlet to the triplet manifold. Core-level X-ray spectroscopy at the carbon-1s K-edge (284 eV) is applied to identify the role of the triplet state (T1, (3)ππ*) in the ultraviolet-induced photochemistry of pentane-2,4-dione (acetylacetone, AcAc)...
November 9, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29073230/spatial-and-temporal-trends-in-fin-whale-vocalizations-recorded-in-the-ne-pacific-ocean-between-2003-2013
#10
Michelle J Weirathmueller, Kathleen M Stafford, William S D Wilcock, Rose S Hilmo, Robert P Dziak, Anne M Tréhu
In order to study the long-term stability of fin whale (Balaenoptera physalus) singing behavior, the frequency and inter-pulse interval of fin whale 20 Hz vocalizations were observed over 10 years from 2003-2013 from bottom mounted hydrophones and seismometers in the northeast Pacific Ocean. The instrument locations extended from 40°N to 48°N and 130°W to 125°W with water depths ranging from 1500-4000 m. The inter-pulse interval (IPI) of fin whale song sequences was observed to increase at a rate of 0.54 seconds/year over the decade of observation...
2017: PloS One
https://www.readbyqxmd.com/read/29071369/erlang-flow-of-hydrophilic-pore-formation-and-closure-events-in-a-lipid-bilayer-during-phase-transition-resulting-from-diffusion-in-the-radius-space
#11
A A Anosov, A A Sharakshane, E Yu Smirnova, O Yu Nemchenko
The Smoluchowski equation with an energy profile of a special type and an assumed hydrophobic ("half") pore source term is used to describe the process of hydrophilic pore formation in a lipid bilayer at the gel-liquid phase transition. The source term reflects the occurrence of molecule packing defects in a lipid bilayer at phase transition. The time sequences of the pore formation and closure events are treated as non-stationary, second-order Erlang flows whose characteristics depend on the equation solution...
October 25, 2017: European Biophysics Journal: EBJ
https://www.readbyqxmd.com/read/29066946/novel-stimulation-paradigms-with-temporally-varying-parameters-to-reduce-synchronous-activity-at-the-onset-of-high-frequency-stimulation-in-rat-hippocampus
#12
Ziyan Cai, Zhouyan Feng, Zheshan Guo, Wenjie Zhou, Zhaoxiang Wang, Xuefeng Wei
Deep brain stimulation (DBS) has shown wide applications for treating various disorders in the central nervous system by using high frequency stimulation (HFS) sequences of electrical pulses. However, upon the onset of HFS sequences, the narrow pulses could induce synchronous firing of action potentials among large populations of neurons and cause a transient phase of "onset response" that is different from the subsequent steady state. To investigate the transient onset phase, the antidromically-evoked population spikes (APS) were used as an electrophysiological marker to evaluate the synchronous neuronal reactions to axonal HFS in the hippocampal CA1 region of anesthetized rats...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/29060948/biosignal-integrated-circuit-with-simultaneous-acquisition-of-ecg-and-ppg-for-wearable-healthcare-applications
#13
Hyungseup Kim, Yunjong Park, Youngwoon Ko, Yeongjin Mun, Sangmin Lee, Hyoungho Ko
BACKGROUND: Wearable healthcare systems require measurements from electrocardiograms (ECGs) and photoplethysmograms (PPGs), and the blood pressure of the user. The pulse transit time (PTT) can be calculated by measuring the ECG and PPG simultaneously. Continuous-time blood pressure without using an air cuff can be estimated by using the PTT. OBJECTIVE: This paper presents a biosignal acquisition integrated circuit (IC) that can simultaneously measure the ECG and PPG for wearable healthcare applications...
October 13, 2017: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
https://www.readbyqxmd.com/read/29060665/robust-motion-artefact-resistant-circuit-for-calculation-of-mean-arterial-pressure-from-pulse-transit-time
#14
Tinish Bhattacharya, Ankesh Gupta, Salam ThoiThoi Singh, Sitikantha Roy, Anamika Prasad
Cuff-less and non-invasive methods of Blood Pressure (BP) monitoring have faced a lot of challenges like stability, noise, motion artefact and requirement for calibration. These factors are the major reasons why such devices do not get approval from the medical community easily. One such method is calculating Blood Pressure indirectly from pulse transit time (PTT) obtained from electrocardiogram (ECG) and Photoplethysmogram (PPG). In this paper we have proposed two novel analog signal conditioning circuits for ECG and PPG that increase stability, remove motion artefacts, remove the sinusoidal wavering of the ECG baseline due to respiration and provide consistent digital pulses corresponding to blood pulses/heart-beat...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060599/low-group-delay-signal-conditioning-for-wearable-central-blood-pressure-monitoring-device
#15
German Fierro, Fernando Silveira, Ricardo Armentano
Pulse transit time (ptt) is a widely researched approach for wearable, unobtrusive, blood pressure monitoring. The estimation of ptt, being a delay measurement, may be affected by the group delay introduced by the signal conditioning chain. In this work a previously reported method for estimating central (aortic) blood pressure from ptt at aortic domain, using ECG R wave and BCG J wave detection, is considered. A simple design approach for the signal conditioning chain, which is suitable for a wearable device and that takes care of minimizing the impact of eventually introduced spurious delays is presented...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060487/blood-pressure-and-cardiovascular-parameters-during-sleep-arousals
#16
Sobhan Salari Shahrbabaki, Beena Ahmed, Thomas Penzel, Dean Cvetkovic
Sleep arousal is generally known as a transient episode of wakefulness into the sleepiness. Sleep arousals can be classified based on their association and accompany with pathological episodes. In this paper, our objective was to find out whether various types of sleep arousals influence on blood pressure and Heart Rate Variability (HRV). We analysed continuous Diastolic and Systolic Blood Pressures (DBP and SBP), Pulse Transit Time (PTT) as well as High and Low Frequency components (HF and LF) of HRV in different types of arousals...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060346/coherence-analysis-of-invasive-blood-pressure-and-its-noninvasive-indicators-for-improvement-of-cuffless-measurement-accuracy
#17
Xiao-Rong Ding, Bryan P Yan, Yuan-Ting Zhang, Jing Liu, Peng Su, Ni Zhao
Cuffless technology for blood pressure (BP) measurement offers great potential for unobtrusive monitoring of hypertension. However, the accuracy is still a challenging issue probably owning to the inadequacy of existing noninvasive BP indicators in tracking BP changes, i.e., either the poor trackability of the indicators or the lack of relationship to map the indicators to BP. To figure out the covariation of BP-related noninvasive indicators and BP, we propose to analyze the coherence of intra-arterial systolic BP (SBP) and a selected group of noninvasive indicators, including the mostly used pulse transit time (PTT), photoplethysmogram intensity ratio (PIR) and RR interval (RRI) of electrocardiogram (ECG), in both time domain, with singular spectrum analysis (SSA), and frequency domain, with cross-spectral analysis...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060318/a-novel-blood-pressure-estimation-method-combing-pulse-wave-transit-time-model-and-neural-network-model
#18
Jun Xu, Jiehui Jiang, Hucheng Zhou, Zhuangzhi Yan
Blood Pressure (BP) measurement can assist doctors to assess patients' cardiovascular status and diagnose heart diseases. Pulse Wave Transit Time (PWTT) model is one frequently used BP estimation method to monitor BP continuously in clinics. However, individual variations may influence the measurement accuracy of PWTT model. Focusing on above promble, this paper proposes a novel BP estimation method combining a classical PWTT model and a neural network model. The novel method is composed of five steps: signal pre-processing, feature extraction, initial PWTT model selection, model correction by neural network model, and final PWTT model identification...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060300/exploration-and-validation-of-alternate-sensing-methods-for-wearable-continuous-pulse-transit-time-measurement-using-optical-and-bioimpedance-modalities
#19
Bassem Ibrahim, Viswam Nathan, Roozbeh Jafari
In this work we explore the viability of a multimodal sensing device that can be integrated in a wearable form factor for daily, non-invasive ambulatory blood pressure (BP) monitoring. A common approach in previous research has been to rely on measuring the pulse transit time (PTT), which has been shown to be correlated with the BP. In this work, we look into the feasibility of measuring PTT using sensors separated by a small distance on one arm so that any eventual realization of the system is convenient to wear and use over long periods of time...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060251/continuous-systolic-and-diastolic-blood-pressure-estimation-utilizing-long-short-term-memory-network
#20
Frank P-W Lo, Charles X-T Li, Jiankun Wang, Jiyu Cheng, Max Q-H Meng
A novel blood pressure estimation method based on long short-term memory neural network, one of the recurrent neural networks being commonly used nowadays, is proposed in this paper for better chronic diseases monitoring. Along with the neural network, a newly proposed ambulatory blood pressure (ABP) processing technique called Two-stage Zero-order Holding (TZH) algorithm has also been presented in the paper. The proposed methodology has the advantages over traditional blood pressure estimation algorithms which are based on Pulse Transit time (PTT)...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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