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https://www.readbyqxmd.com/read/28086909/fast-detection-and-data-compensation-for-electrodes-disconnection-in-long-term-monitoring-of-dynamic-brain-electrical-impedance-tomography
#1
Ge Zhang, Meng Dai, Lin Yang, Weichen Li, Haoting Li, Canhua Xu, Xuetao Shi, Xiuzhen Dong, Feng Fu
BACKGROUND: Electrode disconnection is a common occurrence during long-term monitoring of brain electrical impedance tomography (EIT) in clinical settings. The data acquisition system suffers remarkable data loss which results in image reconstruction failure. The aim of this study was to: (1) detect disconnected electrodes and (2) account for invalid data. METHODS: Weighted correlation coefficient for each electrode was calculated based on the measurement differences between well-connected and disconnected electrodes...
January 7, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28076294/simulation-of-effects-of-the-electrode-structure-and-material-in-the-density-measuring-system-of-the-peripheral-nerve-based-on-micro-electrical-impedance-tomography
#2
Saber Behkami, Javad Frounchi, Firouz Ghaderi Pakdel, Thomas Stieglitz
The electrode structure in micro-electrical impedance tomography (MEIT) highly influences the measurement sensitivity and therefore the reconstructed image quality. Hence, optimizing the electrode structure leads to the improvement of image quality in the reconstruction procedure. Although there have been many investigations on electrical impedance tomography (EIT) electrodes, there is no comprehensive study on their influence on images of the peripheral nerve. In this paper, we present a simulation method to study the effects of the electrode structure in the density measurement system of the peripheral nerve based on MEIT...
January 11, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28068288/monitoring-of-breath-vocs-and-electrical-impedance-tomography-under-pulmonary-recruitment-in-mechanically-ventilated-patients
#3
Beate Brock, Svend Kamysek, Josephine Silz, Phillip Trefz, Jochen K Schubert, Wolfram Miekisch
Analysis of exhaled VOCs can provide information on physiology, metabolic processes, oxidative stress and lung diseases. In critically ill patients, VOC analysis may be used to gain complimentary information beyond global clinical parameters. This seems especially attractive in mechanically ventilated patients frequently suffering from impairment of gas exchange. This study was intended to assess (a) the effects of recruitment maneuvers onto VOC profiles, (b) the correlations between electrical impedance tomography (EIT) data and VOC profiles and (c) the effects of recruitment onto distribution of ventilation...
January 9, 2017: Journal of Breath Research
https://www.readbyqxmd.com/read/28059362/stable-controlling-of-electromagnetically-induced-transparency-like-in-a-single-quasi-cylindrical-microresonator
#4
Xueying Jin, Yongchao Dong, Keyi Wang
We experimentally and theoretically demonstrate electromagnetically induced transparency (EIT)-like and Fano resonance in a single quasi-cylindrical microresonator (QCMR). Stable controlling of the EIT and Fano resonance lineshapes can be achieved by vertically moving the resonator along its axis while in touch with the tapered fiber. Moreover, by horizontally scanning the coupling point along the tapered fiber, asymmetric Fano resonances of the transmission spectra are observed and can be engineered to vary periodically...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28059316/all-optical-tuning-of-eit-like-dielectric-metasurfaces-by-means-of-chalcogenide-phase-change-materials
#5
E Petronijevic, C Sibilia
Electromagnetically induced transparency (EIT) is a pump-induced narrowband transparency window within an absorption line of the probe beam spectrum in an atomic system. In this paper we propose a way to bring together the all-dielectric metamaterials to have EIT-like effects and to optically tune the response by hybridizing them with a layer of a phase change material. We propose a design of the metamaterial based on Si nanoresonators that can support an EIT-like resonant response. On the top of the resonators we consider a thin layer of a chalcogenide phase change material, which we will use to tune the optical response...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28059285/analog-electromagnetically-induced-transparency-for-circularly-polarized-wave-using-three-dimensional-chiral-metamaterials
#6
Hai Lin, Dong Yang, Song Han, Yangjie Liu, Helin Yang
In this paper, we theoretically and experimentally demonstrate a three-dimensional metamaterial that can motivate electromagnetic induced transparency (EIT) by using circular polarized wave as stimulations. The unit cell consists of a pair of metallic strips printed on both sides of the printed circuit board (PCB), where a conductive cylinder junction is used to connect the metal strips by drilling a hole inside the substrate. When a right circularly polarized wave is incident, destructive interference is excited between meta-atoms of the 3D structure, the transmission spectrum demonstrates a sharp transparency window...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28039243/electrical-impedance-tomography-for-non-invasive-assessment-of-stroke-volume-variation-in-health-and-experimental-lung-injury
#7
C J C Trepte, C Phillips, J Solà, A Adler, B Saugel, S Haas, S H Bohm, D A Reuter
BACKGROUND: Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this study was to evaluate SVV measured by EIT (SVVEIT) against SVV from pulse contour analysis (SVVPC) in an experimental animal model of acute lung injury at different lung volumes...
January 2017: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/28036216/inelastic-photon-scattering-via-the-intracavity-rydberg-blockade
#8
A Grankin, E Brion, R Boddeda, S Ćuk, I Usmani, A Ourjoumtsev, P Grangier
Electromagnetically induced transparency (EIT) in a ladder system involving a Rydberg level is known to yield giant optical nonlinearities for the probe field, even in the few-photon regime. This enhancement is due to the strong dipole-dipole interactions between Rydberg atoms and the resulting excitation blockade phenomenon. In order to study such highly correlated media, ad hoc models or low-excitation assumptions are generally used to tackle their dynamical response to optical fields. Here, we study the behavior of a cavity Rydberg-EIT setup in the nonequilibrium quantum field formalism, and we obtain analytic expressions for elastic and inelastic components of the cavity transmission spectrum, valid up to higher excitation numbers than previously achieved...
December 16, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/28035169/understanding-the-physical-nature-of-coronal-eit-waves
#9
D M Long, D S Bloomfield, P F Chen, C Downs, P T Gallagher, R-Y Kwon, K Vanninathan, A M Veronig, A Vourlidas, B Vršnak, A Warmuth, T Žic
For almost 20 years the physical nature of globally propagating waves in the solar corona (commonly called "EIT waves") has been controversial and subject to debate. Additional theories have been proposed over the years to explain observations that did not agree with the originally proposed fast-mode wave interpretation. However, the incompatibility of observations made using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory with the fast-mode wave interpretation was challenged by differing viewpoints from the twin Solar Terrestrial Relations Observatory spacecraft and data with higher spatial and temporal resolution from the Solar Dynamics Observatory...
2017: Solar Physics
https://www.readbyqxmd.com/read/28004642/linearity-of-electrical-impedance-tomography-during-maximum-effort-breathing-and-forced-expiration-maneuvers
#10
Chuong Ngo, Steffen Leonhardt, Tony Zhang, Markus Lüken, Berno Misgeld, Thomas Vollmer, Klaus Tenbrock, Sylvia Lehmann
Electrical impedance tomography (EIT) provides global and regional information about ventilation by means of relative changes in electrical impedance measured with electrodes placed around the thorax. In combination with lung function tests, e.g. spirometry and body plethysmography, regional information about lung ventilation can be achieved. Impedance changes strictly correlate with lung volume during tidal breathing and mechanical ventilation. Initial studies presumed a correlation also during forced expiration maneuvers...
January 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28000769/characterization-of-blunt-chest-trauma-in-a-long-term-porcine-model-of-severe-multiple-trauma
#11
K Horst, T P Simon, R Pfeifer, M Teuben, K Almahmoud, Q Zhi, S Aguiar Santos, C Castelar Wembers, S Leonhardt, N Heussen, P Störmann, B Auner, B Relja, I Marzi, A T Haug, M van Griensven, M Kalbitz, M Huber-Lang, R Tolba, L K Reiss, S Uhlig, G Marx, H C Pape, F Hildebrand
Chest trauma has a significant relevance on outcome after severe trauma. Clinically, impaired lung function typically occurs within 72 hours after trauma. However, the underlying pathophysiological mechanisms are still not fully elucidated. Therefore, we aimed to establish an experimental long-term model to investigate physiological, morphologic and inflammatory changes, after severe trauma. Male pigs (sus scrofa) sustained severe trauma (including unilateral chest trauma, femur fracture, liver laceration and hemorrhagic shock)...
December 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27999152/optimizing-peep-by-electrical-impedance-tomography-in-a-porcine-animal-model-of-ards
#12
Nadine Hochhausen, Ingeborg Biener, Rolf Rossaint, Andreas Follmann, Christian Bleilevens, Till Braunschweig, Steffen Leonhardt, Michael Czaplik
BACKGROUND: Mechanical ventilation is necessary in diverse clinical circumstances. Especially in the context of ARDS, so-called protective ventilation strategies must be followed. It is already known that PEEP might enhance oxygenation in ARDS. However, determining the optimal PEEP settings in clinical routines is challenging. Electrical impedance tomography (EIT) is a promising technique with which to adjust ventilator settings. We investigated whether the combination of different EIT parameters, namely the global inhomogeneity and hyperdistension indices, may lead to a feasible and safe PEEP setting...
December 20, 2016: Respiratory Care
https://www.readbyqxmd.com/read/27984882/simultaneous-observations-of-electromagnetically-induced-transparency-eit-and-absorption-eia-in-a-multi-level-v-type-system-of-87-rb-and-theoretical-simulation-of-the-observed-spectra-using-a-multi-mode-approach
#13
Bankim Chandra Das, Dipankar Bhattacharyya, Arpita Das, Shrabana Chakrabarti, Sankar De
We report here simultaneous experimental observation of Electromagnetically Induced Transparency (EIT) and Electromagnetically Induced Absorption (EIA) in a multi-level V-type system in D2 transition of Rb87, i.e., F=2→F(') with a strong pump and a weak probe beam. We studied the probe spectrum by locking the probe beam to the transition F=2→F(')=2 while the pump is scanned from F=2→F('). EIA is observed for the open transition (F=2→F(')=2) whereas EIT is observed in the closed transition (F=2→F(')=3)...
December 14, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27973479/nonparaxial-self-accelerating-beams-in-an-atomic-vapor-with-electromagnetically-induced-transparency
#14
Hua Zhong, Yiqi Zhang, Zhaoyang Zhang, Changbiao Li, Da Zhang, Yanpeng Zhang, Milivoj R Belić
We theoretically and numerically investigate the nonparaxial self-accelerating beams in a Λ-type three-level energy system of rubidium atomic vapor in the electromagnetically induced transparency (EIT) window. In the EIT window, the absorption of the atomic vapor is small, and robust nonparaxial self-accelerating beams can be generated. The reason is that the energy of the tail transfers to the main lobe, which then maintains its shape, owing to the self-healing effect. Media with large absorption would demand large energy to compensate, and the tail would be lifted too high to maintain the profile of an accelerating beam, so that self-accelerating beams cannot be obtained any longer...
December 15, 2016: Optics Letters
https://www.readbyqxmd.com/read/27958593/comparison-of-coherently-coupled-multi-cavity-and-quantum-dot-embedded-single-cavity-systems
#15
Serdar Kocaman, Gönül Turhan Sayan
Temporal group delays originating from the optical analogue to electromagnetically induced transparency (EIT) are compared in two systems. Similar transmission characteristics are observed between a coherently coupled high-Q multi-cavity array and a single quantum dot (QD) embedded cavity in the weak coupling regime. However, theoretically generated group delay values for the multi-cavity case are around two times higher. Both configurations allow direct scalability for chip-scale optical pulse trapping and coupled-cavity quantum electrodynamics (QED)...
December 12, 2016: Optics Express
https://www.readbyqxmd.com/read/27932671/coupling-of-eit-with-computational-lung-modeling-for-predicting-patient-specific-ventilatory-responses
#16
Christian J Roth, Tobias Becher, Inez Frerichs, Norbert Weiler, Wolfgang A Wall
Providing personalised optimal mechanical ventilation for patients with acute or chronic respiratory failure is still a challenge within a clinical setting for each case anew. In this article, we integrate electrical impedance tomography (EIT) monitoring into a powerful patient-specific computational lung model to create an approach for personalising protective ventilatory treatment. The underlying computational lung model is able to predict global quantities e.g., tracheal flow and tidal volume, as well as local tissue aeration and strains for any ventilation manoeuvre...
December 8, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27910465/accelerated-reconstruction-of-electrical-impedance-tomography-images-via-patch-based-sparse-representation
#17
Qi Wang, Zhijie Lian, Jianming Wang, Qingliang Chen, Yukuan Sun, Xiuyan Li, Xiaojie Duan, Ziqiang Cui, Huaxiang Wang
Electrical impedance tomography (EIT) reconstruction is a nonlinear and ill-posed problem. Exact reconstruction of an EIT image inverts a high dimensional mathematical model to calculate the conductivity field, which causes significant problems regarding that the computational complexity will reduce the achievable frame rate, which is considered as a major advantage of EIT imaging. The single-step method, state estimation method, and projection method were always used to accelerate reconstruction process. The basic principle of these methods is to reduce computational complexity...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27900297/effects-of-lymphatic-drainage-and-local-cryo-exposition-regeneration-after-high-intensive-exercises
#18
Michael Behringer, Diana Jedlicka, Molly McCourt, Matthias Ring, Joachim Mester
BACKGROUND: Recovery from exercise and competition is important in sports medicine, particularly when rest periods are short. The objective is to determine the efficacy of cryo exposition (CRY) and manual lymphatic drainage (MLD) to hasten short term recovery of muscle performance after eccentric contractions. METHODS: In a randomized controlled trial, 30 healthy sport students (21 males, 9 females; age: 25.7±2.8 years) performed 4×20 eccentric contractions of knee extensors, followed by 30 min MLD, CRY, or rest (RST) under controlled laboratory environment...
April 2016: Muscles, Ligaments and Tendons Journal
https://www.readbyqxmd.com/read/27897221/plasmonic-metalens-based-on-coupled-resonators-for-focusing-of-surface-plasmons
#19
Quan Xu, Xueqian Zhang, Yuehong Xu, Quan Li, Yanfeng Li, Chunmei Ouyang, Zhen Tian, Jianqiang Gu, Wentao Zhang, Xixiang Zhang, Jiaguang Han, Weili Zhang
As an essential functionality, flexible focusing of surface plasmons (SPs) is of particular interest in nonlinear optics and highly integrated plasmonic circuitry. Here, we developed a versatile plasmonic metalens, a metasurface comprised of coupled subwavelength resonators, whose optical responses exhibit a remarkable feature of electromagnetically induced transparency (EIT). We demonstrate numerically and experimentally how a proper spatial design of the unit elements steers SPs to arbitrary foci based on the holographic principles...
November 29, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27897152/a-novel-multi-frequency-electrical-impedance-tomography-spectral-imaging-algorithm-for-early-stroke-detection
#20
Lin Yang, Canhua Xu, Meng Dai, Feng Fu, Xuetao Shi, Xiuzhen Dong
Multi-frequency electrical impedance tomography (MFEIT) reconstructs the image of conductivity inside the human body based on the dependence of tissue conductivity on frequency. As there exist differences in the conductivity over frequency between blood, ischemic cortical tissue and normal cortical tissue, MFEIT has potential application in the detection of acute stroke. However, because the conductivity distribution of the human head is highly inhomogeneous and the conductivities of normal head tissue and stroke lesion tissue both change with frequency, the anomaly and normal head tissues are often mixed together in the reconstructed image, which makes it difficult to discern the anomaly...
December 2016: Physiological Measurement
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