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https://www.readbyqxmd.com/read/29145478/electrical-impedance-tomography-amplitudes-of-cardiac-related-impedance-changes-in-the-lung-are-highly-position-dependent
#1
Michael Graf, Thomas Riedel
BACKGROUND: Electrical impedance tomography (EIT) is used on the thorax to measure impedance changes due to the presence of air and blood in the lung. This experimental study was performed to investigate the effect of posture on cardiac and respiratory related impedance changes. METHODS: EIT measurements were performed on 14 healthy subjects in left-, right lateral, prone, supine and upright positions. Simultaneously, tidal volume was recorded with an ultrasonic flowmeter...
2017: PloS One
https://www.readbyqxmd.com/read/29136345/regional-lung-function-testing-in-children-using-electrical-impedance-tomography
#2
Barbara Vogt, Sarah Löhr, Zhanqi Zhao, Christian Falkenberg, Tobias Ankermann, Norbert Weiler, Inéz Frerichs
OBJECTIVE: To evaluate regional lung function in lung-healthy children before and after exercise challenge using electrical impedance tomography (EIT). METHODS: Regional lung function was examined using EIT in 100 lung-healthy children (three age subgroups: 74-121, 122-155, 156-195 months) at baseline and 10 min after exercise. Global lung function was assessed by spirometry using Z-Scores of FEV1 , FVC, FEV1 /FVC, and FEF75 . The same lung function measures were determined in 912 EIT image pixels to enable the spatial and temporal ventilation distribution analysis...
November 14, 2017: Pediatric Pulmonology
https://www.readbyqxmd.com/read/29108470/the-chinese-version-of-the-brief-assessment-of-cognition-in-affective-disorders-normative-data-of-a-mandarin-speaking-population
#3
Chun-Yi Lee, Sheng-Yu Lee, Yu-Chi Huang, Chi-Fa Hung, Yu Lee, Meng-I Lee, Liang-Jen Wang
OBJECTIVE: The Brief Assessment of Cognition in Affective Disorders (BAC-A) is administered to assess the cognitive impairments in patients with affective disorders. This study aims to develop the normative data and to explore the factor structure of the Chinese version of the BAC-A in a Mandarin-speaking population. METHOD: This cross-sectional study consisted of 220 healthy participants (age range: 19-79 years; mean age: 51.5 ± 15.9 years, 48.2% male) in communities in Taiwan...
November 6, 2017: Clinical Neuropsychologist
https://www.readbyqxmd.com/read/29099725/limitations-and-challenges-of-eit-based-monitoring-of-stroke-volume-and-pulmonary-artery-pressure
#4
Fabian Braun, Martin Proença, Mathieu Lemay, Mattia Bertschi, Andy Adler, Jean-Philippe Thiran, Josep Sola
<i>Objective</i>: Electrical impedance tomography (EIT) shows potential for radiation-free and non-invasive hemodynamic monitoring. However, many factors degrade the accuracy and repeatability of these measurements. Our goal is to estimate the impact of this variability on EIT-based monitoring of two important central hemodynamic parameters: stroke volume (SV) and pulmonary artery pressure (PAP). <i>Approach</i>: We performed simulations on a 4D (3D + t) bioimpedance model of a human volunteer to study the influence of four potential confounding factors (electrode belt displacement, electrode detachment, changes in hematocrit and lung air volume) on the performance of EIT-based SV and PAP estimation...
November 3, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/29060676/gamma-variate-modeling-of-indicator-dilution-curves-in-electrical-impedance-tomography
#5
Benjamin Hentze, Thomas Muders, Henning Luepschen, Steffen Leonhardt, Christian Putensen, Marian Walter
Electrical impedance tomography (EIT) is a non-invasive imaging technique, that can be used to monitor regional lung ventilation (V̇) in intensive care units (ICU) at bedside. This work introduces a method to extract regional lung perfusion (Q̇) from EIT image streams in order to quantify regional gas exchange in the lungs. EIT data from a single porcine animal trial, recorded during injection of a contrast agent (NaCl 10%) into a central venous catheter (CVC), are used for evaluation. Using semi-negative matrix factorization (Semi-NMF) a set of source signals is extracted from the data...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29060135/an-electrical-impedance-tomography-eit-multi-electrode-needle-probe-device-for-local-assessment-of-heterogeneous-tissue-impeditivity
#6
Davide Meroni, Camilla Carpano Maglioli, Dario Bovio, Francesco G Greco, Andrea Aliverti
Electrical Impedance Tomography (EIT) is an image reconstruction technique applied in medicine for the electrical imaging of living tissues. In literature there is the evidence that a large resistivity variation related to the differences of the human tissues exists. As a result of this interest for the electrical characterization of the biological samples, recently the attention is also focused on the identification and characterization of the human tissue, by studying the homogeneity of its structure. An 8 electrodes needle-probe device has been developed with the intent of identifying the structural inhomogeneities under the surface layers...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059926/feasibility-study-of-imaging-fast-neural-activity-in-retinal-tissue-using-electrical-impedance-tomography
#7
Danyi Zhu, Xiunan Fang, Calvin Eiber, James Avery, David Holder, Alistair McEwan
Electrical Impedance Tomography has been recently applied to image fast neural activity in the somatosensory cerebral cortex. This non-invasive imaging modality has the unique advantage of high spatial-temporal resolution in millimeters over milliseconds. This work was designed to test an existing 32-channel EIT system, a modified UCL ScouseTom, and to discuss the feasibility of imaging neural activity in retinal tissue through computer simulation. The finite element method was used to model a retinal slice with a realistic conductivity-depth profile of the macaque eye...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059883/monitoring-of-cardiac-output-and-lung-ventilation-by-electrical-impedance-tomography-in-a-porcine-model-of-acute-lung-injury
#8
Nadine Hochhausen, Henriette Dohmeier, Rolf Rossaint, Michael Czaplik
Adequate medical treatment of the Acute Respiratory Distress Syndrome is still challenging since patient-individual aspects have to be taken into account. Lung protective ventilation and hemodynamic stability have always been two of the most crucial aims of intensive care therapy. For both aspects, a continuous - preferably non-invasive - monitoring is desirable that is available at the bedside. Unfortunately, there is no technique clinically established yet, that provides both measurement of cardiac stroke volume and ventilation dynamics in real-time...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059882/imaging-of-regional-air-distributions-in-porcine-lungs-using-high-performance-electrical-impedance-tomography-system
#9
G Y Jang, Y B Kim, H Wi, T I Oh, C R Chung, G Y Suh, E J Woo
Electrical impedance tomography (EIT) allows functional imaging of regional lung ventilation for real-time bedside monitoring of mechanically ventilated patients. Images showing time-changes of regional air distributions in the lungs can provide valuable diagnostic information for lung protective mechanical ventilation. This paper reports in vivo porcine imaging experiments of regional lung ventilation using a 16-channel parallel EIT system. Real-time time-difference chest images of 10 animals were reconstructed during mechanical ventilations with a temporal resolution of 50 frame/s...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059834/electrical-properties-of-phantoms-for-mimicking-breast-tissue
#10
Vinicius G Sirtoli, Kaue Morcelles, Pedro Bertemes-Filho
In order to test and calibrate an EIT (Electrical Impedance Tomography) system, many researchers rely on phantoms mimicking breast tissues. These phantoms are usually made of saline solutions, agar and/or vegetables, allowing the user to set the conductivity of the material by changing the salt concentration. Due to that fact that the dispersion behavior in the vicinity of megahertz is fundamental to detect carcinoma, this work aims to propose a phantom composed by a mixture of agar and gelatin (emulating the normal tissue) and a piece of carrot (emulating the carcinoma)...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059801/integration-of-piezo-capacitive-and-piezo-electric-nanoweb-based-pressure-sensors-for-imaging-of-static-and-dynamic-pressure-distribution
#11
Y J Jeong, T I Oh, E J Woo, K J Kim
Recently, highly flexible and soft pressure distribution imaging sensor is in great demand for tactile sensing, gait analysis, ubiquitous life-care based on activity recognition, and therapeutics. In this study, we integrate the piezo-capacitive and piezo-electric nanowebs with the conductive fabric sheets for detecting static and dynamic pressure distributions on a large sensing area. Electrical impedance tomography (EIT) and electric source imaging are applied for reconstructing pressure distribution images from measured current-voltage data on the boundary of the hybrid fabric sensor...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29047882/method-proposing-a-slow-light-ring-resonator-structure-coupled-with-a-metal-dielectric-metal-waveguide-system-based-on-plasmonic-induced-transparency
#12
Mehdi Hassani Keleshtery, Hassan Kaatuzian, Ali Mir, Ashkan Zandi
We demonstrate the analogue of electromagnetically induced transparency (EIT) in a metal-dielectric-metal (MDM) plasmonic waveguide. Plasmonic induced transparency is a method similar to EIT. In this paper, a plasmonic MDM waveguide is proposed by using an ellipse shaped side-coupled ring resonator and simulated by finite difference time domain. Plasmonics as a new field of chip-scale technology is an interesting substrate, which is used to propose and numerically investigate a novel MDM structure. The aforementioned framework is a 2×2 plasmonic ring resonator, employing gold as a metal and polymethyl methacrylate as a dielectric...
May 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/29041671/tailoring-the-plasmon-induced-transparency-resonances-in-terahertz-metamaterials
#13
Meng Liu, Zhen Tian, Xueqian Zhang, Jianqiang Gu, Chunmei Ouyang, Jiaguang Han, Weili Zhang
We experimentally demonstrate that a coupled metamaterial composed of sub-wavelength split-ring-resonators (SRRs) and closed-ring-resonators (CRRs) can tailor the plasmon-induced-transparency (PIT) resonances when the external electric field is parallel to the gaps of SRRs. Rotating or moving SRRs in vertical direction plays a critical role in the EIT functionality, while an excellent robust performance can be acquired via moving SRRs in the horizontal direction. Based on the results, a polarization-independent and polarization-dependent planar metamaterial are designed, fabricated and measured...
August 21, 2017: Optics Express
https://www.readbyqxmd.com/read/29041642/weak-light-vector-rogue-waves-breathers-and-their-stern-gerlach-deflection-via-electromagnetically-induced-transparency
#14
Junyang Liu, Chao Hang, Guoxiang Huang
We propose a scheme for generating and manipulating vector (or two-component) optical rogue waves using Akhmediev and Kuznetsov-Ma breathers in a coherent atomic system with an M-type five-level configuration via electromagnetically induced transparency (EIT). We show that the propagation velocity of these nonlinear excitations can be reduced to 10(-4)c and their generation power can be lowered to microwatts. We also show that the motion trajectories of the two polarization components in these excitations can be deflected significantly by using a transversal gradient magnetic field, similar to the Stern-Gerlach effect of an atomic beam...
September 18, 2017: Optics Express
https://www.readbyqxmd.com/read/29041609/optical-chirality-breaking-in-a-bilayered-chiral-metamaterial
#15
Jianxing Zhao, Yuegang Fu, Zhiying Liu, Jianhong Zhou
We propose a planar optical bilayered chiral metamaterial, which consists of periodic metallic arrays of two L-shaped structures and a nanorod twisted on both sides of a dielectric slab, to investigate the optical chirality breaking effect by using finite-difference time-domain (FDTD) method. Even the metamaterial is with chiral symmetry, an optical chirality breaking window in the asymmetric transmission pass band is obtained in chiral metamaterial structure. We analyze the plasmonic mode properties and attribute the mechanism of the optical chirality breaking effect to the plasmonic analogue of EIT...
September 18, 2017: Optics Express
https://www.readbyqxmd.com/read/29041470/coherence-effects-in-electromagnetically-induced-transparency-in-v-type-systems-of-87-rb
#16
Hyun-Jong Kang, Heung-Ryoul Noh
We present a theoretical and experimental study of electromagnetically induced transparency (EIT) in V-type systems of (87)Rb atoms. We calculate accurate lineshapes of V-type EIT spectra by solving density matrix equations considering all the magnetic sublevels involved. The calculated spectra demonstrate consistency with the experimental results. We identify the coherence effect in the calculated EIT spectra, and determine that the coherence effect exists only in the cycling transition. We explain the reason for the suppression of the coherence effect in open transitions using an analytical calculation of the spectra for a simple V-type three-level atomic system...
September 4, 2017: Optics Express
https://www.readbyqxmd.com/read/29041386/localized-terahertz-electromagnetically-induced-transparency-like-phenomenon-in-a-conductively-coupled-trimer-metamolecule
#17
Zhenyu Zhao, Xiaobo Zheng, Wei Peng, Jianbing Zhang, Hongwei Zhao, Zhijian Luo, Wangzhou Shi
We experimentally investigate the terahertz (THz) electromagnetically-induced transparency (EIT)-like phenomenon in a metamolecule (MM) of three-body system. This system involves a couple of geometrically identical split-ring resonators (SRRs) in orthogonal layout conductively coupled by a cut-wire resonator. Such a three-body system exhibits two frequency response properties upon to the polarization of incident THz beam: One is the dark-bright-bright layout to the horizontally polarized THz beam, where there is no EIT-like effect; the other is bright-dark-dark layout to the vertically polarized THz beam, where an EIT-like effect is observable...
October 2, 2017: Optics Express
https://www.readbyqxmd.com/read/29041373/dual-band-unidirectional-reflectionless-phenomena-in-an-ultracompact-non-hermitian-plasmonic-waveguide-system-based-on-near-field-coupling
#18
Cong Zhang, Ruiping Bai, Xintong Gu, Xing Ri Jin, Ying Qiao Zhang, YoungPak Lee
Dual-band unidirectional reflectionlessness and coherent perfect absorption (CPA) are demonstrated in a non-Hermitian plasmonic waveguide system based on near-field coupling between a single resonator and the resonant modes of two resonators showing an electromagnetically induced-transparency-like (EIT-like) effect. The non-Hermitian plasmonic system consists of three metal-insulator-metal (MIM) resonators coupled to a MIM plasmonic waveguide.
October 2, 2017: Optics Express
https://www.readbyqxmd.com/read/29041230/compact-tunable-electromagnetically-induced-transparency-and-fano-resonance-on-silicon-platform
#19
Shuang Zheng, Zhengsen Ruan, Shengqian Gao, Yun Long, Shimao Li, Mingbo He, Nan Zhou, Jing Du, Li Shen, Xinlun Cai, Jian Wang
We propose and demonstrate an on-chip coupling resonant system to generate electromagnetically induced transparency (EIT)-like effect and Fano resonance on silicon platform. It is composed of a microring resonator (MRR) and two cascaded Sagnac-loop mirrors (SLMs) assisted Fabry-Perot (FP) cavity on silicon-on-insulator. According to the coupling conditions of the MRR, two cases are studied theoretically. When the MRR is over coupling, EIT-like transmission can be observed. In contrast, Fano resonances can be generated by the condition of under coupling...
October 16, 2017: Optics Express
https://www.readbyqxmd.com/read/29041103/ultraslow-weak-light-solitons-and-their-storage-and-retrieval-in-a-kagome-structured-hollow-core-photonic-crystal-fiber
#20
Datang Xu, Zhiming Chen, Guoxiang Huang
We investigate the formation and propagation of ultraslow weak-light solitons and their memory in the atomic gas filled in a kagome-structured hollow-core photonic crystal fiber (HC-PCF) via electromagnetically induced transparency (EIT). We show that, due to the strong light-atom coupling contributed by the transverse confinement of the HC-PCF, the EIT and hence the optical Kerr nonlinearity of the system can be largely enhanced, and hence optical solitons with very short formation distance, ultraslow propagation velocity, and extremely low generation power can be realized...
August 7, 2017: Optics Express
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