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Pulse transit time

Karin Henriette Wodack, Sarah Buehler, Sarah A Nishimoto, Michael F Graessler, Christoph R Behem, Andreas Daniel Waldmann, Beat Mueller, Stephan H Böhm, Eugenijus Kaniusas, Florian Thürk, Alexander Maerz, Constantin J C Trepte, Daniel A Reuter
Electrical impedance tomography (EIT) is a noninvasive and radiation free bedside monitoring technology, primarily used to monitor lung function. First experimental data shows that the descending aorta can be detected at different thoracic heights and might allow the assessment of central hemodynamics, i.e. stroke volume and pulse transit time. Approach: First, the feasibility of localizing small non-conductive objects within a saline phantom model was evaluated. Second, this result was utilized for the detection of the aorta by EIT in ten anesthetized pigs in with comparison to thoracic computer tomography (CT)...
January 19, 2018: Physiological Measurement
Ran Finkelstein, Eilon Poem, Ohad Michel, Ohr Lahad, Ofer Firstenberg
Future quantum photonic networks require coherent optical memories for synchronizing quantum sources and gates of probabilistic nature. We demonstrate a fast ladder memory (FLAME) mapping the optical field onto the superposition between electronic orbitals of rubidium vapor. Using a ladder-level system of orbital transitions with nearly degenerate frequencies simultaneously enables high bandwidth, low noise, and long memory lifetime. We store and retrieve 1.7-ns-long pulses, containing 0.5 photons on average, and observe short-time external efficiency of 25%, memory lifetime (1/e) of 86 ns, and below 10-4 added noise photons...
January 2018: Science Advances
Vasilis Tsimihodimos, Clicerio Gonzalez-Villalpando, James B Meigs, Ele Ferrannini
Type 2 diabetes mellitus and hypertension overlap in the population. In many subjects, development of diabetes mellitus is characterized by a relatively rapid increase in plasma glucose values. Whether a similar phenomenon occurs during the development of hypertension is not known. We analyzed the pattern of blood pressure (BP) changes during the development of hypertension in patients with or without diabetes mellitus using data from the MCDS (Mexico City Diabetes Study; a population-based study of diabetes mellitus in Hispanic whites) and in the FOS (Framingham Offspring Study, a community-based study in non-Hispanic whites) during a 7-year follow-up...
January 15, 2018: Hypertension
Yongchang Dong, Sergii Chertopalov, Kathleen Maleski, Babak Anasori, Longyu Hu, Sriparna Bhattacharya, Apparao M Rao, Yury Gogotsi, Vadym N Mochalin, Ramakrishna Podila
MXenes comprise a new class of 2D transition metal carbides, nitrides, and carbonitrides that exhibit unique light-matter interactions. Recently, 2D Ti3 CNTx (Tx represents functional groups such as OH and F) was found to exhibit nonlinear saturable absorption (SA) or increased transmittance at higher light fluences, which is useful for mode locking in fiber-based femtosecond lasers. However, the fundamental origin and thickness dependence of SA behavior in MXenes remain to be understood. 2D Ti3 C2 Tx thin films of different thicknesses are fabricated using an interfacial film formation technique to systematically study their nonlinear optical properties...
January 15, 2018: Advanced Materials
Tony C Smith, Dennis J Clouthier
The SnH2 and SnD2 molecules have been detected for the first time in the gas phase by laser-induced fluorescence (LIF) and emission spectroscopic techniques through the Ã1B1-X̃1A1 electronic transition. These reactive species were prepared in a pulsed electric discharge jet using (CH3)4Sn or SnH4/SnD4 precursors diluted in high pressure argon. Transitions to the electronic excited state of the jet-cooled molecules were probed with LIF, and the ground state energy levels were measured from single rovibronic level emission spectra...
January 14, 2018: Journal of Chemical Physics
Smriti Sahu, Rituraj Sharma, K V Adarsh, Anbarasu Manivannan
Rapid and reversible switching between amorphous and crystalline phases of phase-change material promises to revolutionize the field of information processing with a wide range of applications including electronic, optoelectronics, and photonic memory devices. However, achieving faster crystallization is a key challenge. Here, we demonstrate femtosecond-driven transient inspection of ultrafast crystallization of as-deposited amorphous Ge1Sb2Te4 and Ge1Sb4Te7 thin films induced by a series of 120 fs laser pulses...
January 10, 2018: Applied Optics
Pamela A Santibáñez, Olivia J Maselli, Mark C Greenwood, Mackenzie M Grieman, Eric S Saltzman, Joseph R McConnell, John C Priscu
We present the first long-term, highly resolved prokaryotic cell concentration record obtained from a polar ice core. This record, obtained from the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core, spanned from the Last Glacial Maximum (LGM) to the early Holocene (EH) and showed distinct fluctuations in prokaryotic cell concentration coincident with major climatic states. The time series also revealed a ~1,500-year periodicity with greater amplitude during the Last Deglaciation (LDG). Higher prokaryotic cell concentration and lower variability occurred during the LGM and EH than during the LDG...
January 11, 2018: Global Change Biology
Wan-Hua Lin, Hui Wang, Oluwarotimi Williams Samuel, Gengxing Liu, Zhen Huang, Guanglin Li
Objective: The accuracy of cuffless and continuous blood pressure (BP) estimation has been improved, but it is still unsatisfactory for clinical uses. This study was designed to further increase BP estimation accuracy. Approach: In this study, a number of new indicators were extracted from photoplethysmogram (PPG) recordings and linear regression method was used to construct BP estimation models based on the PPG indicators and pulse transit time (PTT). The performance of the BP estimation models was evaluated by the PPG recordings from 22 subjects when they performed mental arithmetic stress and Valsalva's manoeuvre tasks that could induce BP fluctuations...
December 28, 2017: Physiological Measurement
Stefan Thomas Kotzian, Angela Schwarzinger, Sandra Haider, Bernd Saletu, Josef Spatt, Michael Timothy Saletu
INTRODUCTION: Meta-analyses report that more than 50% of patients who had a stroke suffer from moderate to severe sleep apnoea (SA), with adherence rates to positive airway pressure (PAP) therapy of only 30%. The primary objective of this study is to determine whether PAP adherence in patients who had a stroke with obstructive sleep apnoea (OSA) can be improved by a PAP training strategy during inhospital rehabilitation combined with a telemedicine monitoring system after discharge. Further objectives are (1) to compare the validity of a non-attended level-III polygraphy with that of a level-II polysomnography (PSG) in the diagnosis of SA, (2) to compare the validity of an apnoea-hypopnoea index (AHI) yielded by the PAP device with that obtained during PSG, (3) to determine changes in nocturnal systolic blood pressure (BP) due to PAP therapy with the pulse transit time (PTT) method and (4) to assess the impact of telemonitored PAP therapy on neurorehabilitation outcome parameters...
January 9, 2018: BMJ Open
Ivan V Shelaev, Mahir D Mamedov, Fedor E Gostev, Arseny V Aybush, Meng Li, Jonathan Nguyen, Barry D Bruce, Victor A Nadtochenko
Photosystem I (PSI) is a Type-I reaction center and the largest photosynthetic complex to be characterized. In cyanobacteria, PSI is organized as a trimer with a three-fold axis of symmetry. Recently, a tetrameric form of PSI has been identified in cyanobacteria. Plastids in plants and algae only contain monomeric PSI, suggesting that tetrameric PSI may be key in the transition from ancestral cyanobacterial trimeric PSI to plant/algal monomeric PSI. We have investigated the kinetics of e- transfer to the initial acceptor in PSI tetramer isolated from Chroococcidiopsis TS-821...
January 8, 2018: Photochemistry and Photobiology
Lizhen Ji, Chengyu Liu, Peng Li, Xinpei Wang, Changchun Liu, Yinglong Hou
Pulse wave transit time (PWTT) has been widely used as an index in assessing arterial stiffness. Percutaneous coronary intervention (PCI) is usually applied to the treatment of coronary artery disease (CAD). Research on the changes in PWTT caused by PCI is helpful for understanding the impact of the PCI procedure. In addition, effects of stent sites and access sites on the changes in PWTT have not been explored. Consequently, this study aimed to provide this information. The results showed that PWTT significantly increased after PCI (p < 0...
January 8, 2018: Scientific Reports
M Mchalwat, H Ulrichs, J Walowski, C Ballani, O Shapoval, V Moshnyaga, M Münzenberg, K Samwer
We report photoinduced effects in nonlinear third harmonic ac electric transport-which is a measure for the density of correlated polarons-in thin films of [Formula: see text] (LBMO) and [Formula: see text] (LPCMO) manganites. Both materials show an enhancement of third harmonic voltage in the vicinity of the metal-to-insulator transition, indicating strong electron-lattice correlations within a phase-separated state. Relatively low laser excitation with a pulse fluence of [Formula: see text] leads to an increase (decrease) in nonlinearity in LBMO (LPCMO)...
January 4, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Mozhgan Arabi, Seyyed Mahdy Baizaee, Alireza Bahador, Seyed Mohammad Taheri Otaqsara
Zinc oxide (ZnO) and ZnO:Cu nanoparticles (NPs) were synthesized using a rapid, controllable, one-pot and room-temperature pulsed UV-laser assisted method. UV-laser irradiation was used as an effective energy source in order to gain better control over the NPs size and morphology in aqueous media. Parameters effective in laser assisted synthesis of NPs such as irradiation time and laser shot repetition rate were optimized. Photoluminescence (PL) spectra of ZnO NPs showed a broad emission with two trap state peaks located at 442 and 485 nm related to electronic transition from zinc interstitial level (IZn ) to zinc vacancy level (VZn ) and electronic transition from conduction band to the oxygen vacancy level (VO ), respectively...
December 28, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Lee S Nguyen, Pierre Squara
Critically ill patients require close hemodynamic monitoring to titrate treatment on a regular basis. It allows administering fluid with parsimony and adjusting inotropes and vasoactive drugs when necessary. Although invasive monitoring is considered as the reference method, non-invasive monitoring presents the obvious advantage of being associated with fewer complications, at the expanse of accuracy, precision, and step-response change. A great many methods and devices are now used over the world, and this article focuses on several of them, providing with a brief review of related underlying physical principles and validation articles analysis...
2017: Frontiers in Medicine
S A Siletsky, A V Dyuba, D A Elkina, M V Monakhova, V B Borisov
Recombination of the isolated, fully reduced bd-type quinol oxidase from Escherichia coli with carbon monoxide was studied by pulsed absorption spectrophotometry with microsecond time resolution. Analysis of the kinetic phases of recombination was carried out using the global analysis of multiwavelength kinetic data ("Global fitting"). It was found that the unresolved photodissociation of CO is followed by a stepwise (with four phases) recombination with characteristic times (τ) of about 20 µs, 250 µs, 1...
November 2017: Biochemistry. Biokhimii︠a︡
Shaowei Li, Siyu Chen, Jie Li, Ruqian Wu, W Ho
We report single-molecule conformational transitions with joint angstrom-femtosecond resolution by irradiating the junction of a scanning tunneling microscope with femtosecond laser pulses. An isolated pyrrolidine molecule adsorbed on a Cu(001) surface undergoes reversible transitions between two conformational states. The transition rate decays in time and exhibits sinusoidal oscillations with periods of specific molecular vibrations. The dynamics of this transition depends sensitively on the molecular environment, as exemplified by the effects of another molecule in proximity...
October 27, 2017: Physical Review Letters
Elisa Mejía-Mejía, Robinson Torres, Diana Restrepo
Physiological coherence has been related with a general sense of well-being and improvements in health and physical, social, and cognitive performance. The aim of this study was to evaluate the relationship between acute stress, controlled breathing, and physiological coherence, and the degree of body systems synchronization during a coherence-generation exercise. Thirty-four university employees were evaluated during a 20-min test consisting of four stages of 5-min duration each, during which basal measurements were obtained (Stage 1), acute stress was induced using validated mental stressors (Stroop test and mental arithmetic task, during Stage 2 and 3, respectively), and coherence states were generated using a controlled breathing technique (Stage 4)...
December 7, 2017: Psychophysiology
Manuel Mchalwat, Henning Ulrichs, Jakob Walowski, Camillo Ballani, Oleg Shapoval, Vasily Moshnyaga, Markus Muenzenberg, Konrad Samwer
We report photoinduced effects in the nonlinear third harmonic ac electric transport-which is a measure for the density of correlated polarons-in thin films of La<sub>0.75</sub>Ba<sub>0.25</sub>MnO<sub>3</sub> (LBMO) and (La<sub>0.6</sub>Pr<sub>0.4</sub>)<sub>0.67</sub>Ca<sub>0.33</sub>MnO<sub>3</sub> (LPCMO) manganites. Both materials show an enhancement of the third harmonic voltage in the vicinity of the metal-to-insulator transition, indicating strong electron-lattice correlations within a phase-separated state...
December 6, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Mubashar Rehman, Ayesha Ihsan, Asadullah Madni, Sadia Zafar Bajwa, Di Shi, Thomas J Webster, Waheed S Khan
Thermoresponsive drug delivery systems are designed for the controlled and targeted release of therapeutic payload. These systems exploit hyperthermic temperatures (>39°C), which may be applied by some external means or due to an encountered symptom in inflammatory diseases such as cancer and arthritis. The objective of this paper was to provide some solid evidence in support of the hypothesis that solid lipid nanoparticles (SLNs) can be used for thermoresponsive targeting by undergoing solid-liquid phase transition at their melting point (MP)...
2017: International Journal of Nanomedicine
Vladislav V Serov, Anatoli S Kheifets
We solve the time-dependent Schrödinger equation describing a water molecule driven by a superposition of the extreme ultraviolet and IR pulses typical for a reconstruction of attosecond beating by interference of two-photon transitions experiment. This solution is obtained by a combination of the time-dependent coordinate scaling and the density functional theory with self-interaction correction. Results of this solution are used to determine the time delay in photoionization of the water and hydrogen molecules...
November 28, 2017: Journal of Chemical Physics
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