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https://www.readbyqxmd.com/read/28672798/a-real-time-contactless-pulse-rate-and-motion-status-monitoring-system-based-on-complexion-tracking
#1
Yu-Chen Lin, Nai-Kuan Chou, Guan-You Lin, Meng-Han Li, Yuan-Hsiang Lin
Subject movement and a dark environment will increase the difficulty of image-based contactless pulse rate detection. In this paper, we detected the subject's motion status based on complexion tracking and proposed a motion index (MI) to filter motion artifacts in order to increase pulse rate measurement accuracy. Additionally, we integrated the near infrared (NIR) LEDs with the adopted sensor and proposed an effective method to measure the pulse rate in a dark environment. To achieve real-time data processing, the proposed framework is constructed on a Field Programmable Gate Array (FPGA) platform...
June 24, 2017: Sensors
https://www.readbyqxmd.com/read/28652642/optical-fiber-ultrasound-transmitter-with-electrospun-carbon-nanotube-polymer-composite
#2
Radhika K Poduval, Sacha Noimark, Richard J Colchester, Thomas J Macdonald, Ivan P Parkin, Adrien E Desjardins, Ioannis Papakonstantinou
All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS)...
May 29, 2017: Applied Physics Letters
https://www.readbyqxmd.com/read/28639263/subthalamic-beta-dynamics-mirror-parkinsonian-bradykinesia-months-after-neurostimulator-implantation
#3
Leon Amadeus Steiner, Wolf-Julian Neumann, Franziska Staub-Bartelt, Damian M Herz, Huiling Tan, Alek Pogosyan, Andrea A Kuhn, Peter Brown
BACKGROUND: Exaggerated oscillatory activity in the beta frequency band in the subthalamic nucleus has been suggested to be related to bradykinesia in Parkinson's disease (PD). However, studies seeking correlations between such activity in the local field potential and motor performance have been limited to the immediate postoperative period, which may be confounded by a stun effect that leads to the temporary alleviation of PD deficits. METHODS: Local field potentials were recorded simultaneously with motor performance in PD patients several months after neurostimulator implantation...
June 22, 2017: Movement Disorders: Official Journal of the Movement Disorder Society
https://www.readbyqxmd.com/read/28627331/dynamic-transmit-receive-beamforming-by-spatial-matched-filtering-for-ultrasound-imaging-with-plane-wave-transmission
#4
Yuling Chen, Yang Lou, Jesse Yen
During conventional ultrasound imaging, the need for multiple transmissions for one image and the time of flight for a desired imaging depth limit the frame rate of the system. Using a single plane wave pulse during each transmission followed by parallel receive processing allows for high frame rate imaging. However, image quality is degraded because of the lack of transmit focusing. Beamforming by spatial matched filtering (SMF) is a promising method which focuses ultrasonic energy using spatial filters constructed from the transmit-receive impulse response of the system...
July 2017: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28618605/measurements-of-ionization-states-in-warm-dense-aluminum-with-betatron-radiation
#5
M Z Mo, Z Chen, S Fourmaux, A Saraf, S Kerr, K Otani, R Masoud, J-C Kieffer, Y Tsui, A Ng, R Fedosejevs
Time-resolved measurements of the ionization states of warm dense aluminum via K-shell absorption spectroscopy are demonstrated using betatron radiation generated from laser wakefield acceleration as a probe. The warm dense aluminum is generated by irradiating a free-standing nanofoil with a femtosecond optical laser pulse and was heated to an electron temperature of ∼20-25 eV at a close-to-solid mass density. Absorption dips in the transmitted x-ray spectrum due to the Al^{4+} and Al^{5+} ions are clearly seen during the experiments...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28558937/numerical-simulation-of-time-fractional-dual-phase-lag-model-of-heat-transfer-within-skin-tissue-during-thermal-therapy
#6
Dinesh Kumar, K N Rai
In this paper, we investigated the thermal behavior in living biological tissues using time fractional dual-phase-lag bioheat transfer (DPLBHT) model subjected to Dirichelt boundary condition in presence of metabolic and electromagnetic heat sources during thermal therapy. We solved this bioheat transfer model using finite element Legendre wavelet Galerkin method (FELWGM) with help of block pulse function in sense of Caputo fractional order derivative. We compared the obtained results from FELWGM and exact method in a specific case, and found a high accuracy...
July 2017: Journal of Thermal Biology
https://www.readbyqxmd.com/read/28542010/thermal-modeling-for-the-next-generation-of-radiofrequency-exposure-limits-commentary
#7
Kenneth R Foster, Marvin C Ziskin, Quirino Balzano
This commentary evaluates two sets of guidelines for human exposure to radiofrequency (RF) energy, focusing on the frequency range above the "transition" frequency at 3-10 GHz where the guidelines change their basic restrictions from specific absorption rate to incident power density, through the end of the RF band at 300 GHz. The analysis is based on a simple thermal model based on Pennes' bioheat equation (BHTE) (Pennes 1948) assuming purely surface heating; an Appendix provides more details about the model and its range of applicability...
July 2017: Health Physics
https://www.readbyqxmd.com/read/28497464/in-vivo-proton-observed-carbon-edited-poce-13-c-magnetic-resonance-spectroscopy-of-the-rat-brain-using-a-volumetric-transmitter-and-receive-only-surface-coil-on-the-proton-channel
#8
Chathura Kumaragamage, Dan Madularu, Axel P Mathieu, Henk De Feyter, M Natasha Rajah, Jamie Near
PURPOSE: In vivo carbon-13 ((13) C) MR spectroscopy (MRS) is capable of measuring energy metabolism and neuroenergetics, noninvasively in the brain. Indirect ((1) H-[(13) C]) MRS provides sensitivity benefits compared with direct (13) C methods, and normally includes a (1) H surface coil for both localization and signal reception. The aim was to develop a coil platform with homogenous B1+ and use short conventional pulses for short echo time proton observed carbon edited (POCE) MRS. METHODS: A (1) H-[(13) C] MRS coil platform was designed with a volumetric resonator for (1) H transmit, and surface coils for (1) H reception and (13) C transmission...
May 12, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28466805/aortic-stiffness-evaluated-by-echocardiography-in-female-patients-with-takayasu-s-arteritis
#9
Yong Yang, Zhen Wang, Li-Jun Yuan, Tie-Sheng Cao, Jie Liu, Rong Ren, Yun-You Duan
OBJECTIVES: The aim of this study was to evaluate the aortic stiffness (AS) in young female patients with Takayasu's arteritis (TAK) and comparable controls by measuring carotid-femoral PWV (PWVcf) using echocardiography with pulse wave Doppler. The clinical feasibility and reproducibility of this echocardiographic method were also investigated. METHODS: Twenty-five TAK female patients (mean age 28.3±6.2 years) and 25 strictly matched healthy controls were included according to rigorous inclusion and exclusion criteria...
March 2017: Clinical and Experimental Rheumatology
https://www.readbyqxmd.com/read/28464641/extent-of-lateralization-at-large-interaural-time-differences-in-simulated-electric-hearing-and-bilateral-cochlear-implant-users
#10
Regina M Baumgärtel, Hongmei Hu, Birger Kollmeier, Mathias Dietz
Normal-hearing (NH) listeners are able to localize sound sources with extraordinary accuracy through interaural cues, most importantly interaural time differences (ITDs) in the temporal fine structure. Bilateral cochlear implant (CI) users are also able to localize sound sources, yet generally at lower accuracy than NH listeners. The gap in performance can in part be attributed to current CI systems not faithfully transmitting interaural cues, especially ITDs. With the introduction of binaurally linked CI systems, the presentation of ITD cues for bilateral CI users is foreseeable...
April 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28456246/energy-compression-of-nanosecond-high-voltage-pulses-based-on-two-stage-hybrid-scheme
#11
M R Ulmaskulov, G A Mesyats, A G Sadykova, K A Sharypov, V G Shpak, S A Shunailov, M I Yalandin
Test results of high-voltage subnanosecond pulse generator with a hybrid, two-stage energy compression scheme are presented. After the first compression section with a gas discharger, a ferrite-filled gyromagnetic nonlinear transmitting line is used. The offered technical solution makes it possible to increase the voltage pulse amplitude from -185 kV to -325 kV, with a 2-ns pulse rise time minimized down to ∼180 ps. For the small output voltage amplitude of -240 kV, the shortest pulse front of ∼85 ps was obtained...
April 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28456239/high-speed-microstrip-multi-anode-multichannel-plate-detector-system
#12
Andreas Riedo, Marek Tulej, Urs Rohner, Peter Wurz
High-speed detector systems with high dynamic range and pulse width characteristics in the sub-nanosecond regime are mandatory for high resolution and highly sensitive time-of-flight mass spectrometers. Typically, for a reasonable detector area, an impedance-matched anode design is necessary to transmit the registered signal fast and distortion-free from the anode to the signal acquisition system. In this report, a high-speed microstrip multi-anode multichannel plate detector is presented and discussed. The anode consists of four separate active concentric anode segments allowing a simultaneous readout of signal with a dynamic range of about eight orders of magnitude...
April 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28454043/vacuum-scanning-capillary-photoemission-microscopy
#13
S A Aseyev, A P Cherkun, B N Mironov, V V Petrunin, S V Chekalin
We demonstrate the use of a conical capillary in a scanning probe microscopy for surface analysis. The probe can measure photoemission from a substrate by transmitting photoelectrons along the capillary as a function of probe position. The technique is demonstrated on a model substrate consisting of a gold reflecting layer on a compact disc which has been illuminated by an unfocused laser beam with a wavelength 400nm, from a femtosecond laser with a beam size of 4mm. A quartz capillary with a 2-µm aperture has been used in the experiments...
August 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28444504/correction-of-parallel-transmission-using-concurrent-rf-and-gradient-field-monitoring
#14
Mustafa Çavuşoğlu, Benjamin Emanuel Dietrich, David Otto Brunner, Markus Weiger, Klaas Paul Pruessmann
OBJECTIVES: The accuracy and precision of the parallel RF excitations are highly dependent on the spatial and temporal fidelity of the magnetic fields involved in spin excitation. The consistency between the nominal and effective fields is typically limited by the imperfections of the employed hardware existing both in the gradient system and the RF chain. In this work, we experimentally presented highly improved spatially tailored parallel excitations by turning the native hardware accuracy challenge into a measurement and control problem using an advanced field camera technology to fully correct parallel RF transmission experiment...
April 25, 2017: Magma
https://www.readbyqxmd.com/read/28438666/how-to-choose-the-right-mr-sequence-for-your-research-question-at-7-t-and-above
#15
José P Marques, David G Norris
The choice of a pulse sequence at ultra-high field can be influenced by a number of considerations and constraints that are not always the same as those at lower fields. Foremost amongst these is of course the information required and the time available, but considerations of static main field- and transmit field- inhomogeneities as well as power deposition can also play an important role. In this review we first briefly examine the characteristics of high field MRI, and then describe the performance and constraints relevant to the major imaging readouts, and their implementation with parallel imaging techniques...
April 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/28420761/in-situ-measurements-of-tensile-forces-in-the-tibialis-anterior-tendon-of-the-rat-in-concentric-isometric-and-resisted-co-contractions
#16
Martin Schmoll, Ewald Unger, Hazel Sutherland, Michael Haller, Manfred Bijak, Hermann Lanmüller, Jonathan C Jarvis
Tensile-force transmitted by the tibialis anterior (TA) tendon of 11 anesthetized adult male Wistar rats (body-mass: 360.6 ± 66.3 g) was measured in-situ within the intact biomechanical system of the hind-limb using a novel miniature in-line load-cell. The aim was to demonstrate the dependence of the loading-profile experienced by the muscle, on stimulation-frequency and the resistance to shortening in a group of control-animals. Data from these acute-experiments shows the type of loading achievable by means of implantable electrical stimulators activating agonists or agonist/antagonist groups of muscles during programmed resistance-training in freely moving healthy subjects...
April 2017: Physiological Reports
https://www.readbyqxmd.com/read/28418076/ultrasonic-modulation-of-tissue-optical-properties-in-ex-vivo-porcine-skin-to-improve-transmitted-transdermal-laser-intensity
#17
Paul J D Whiteside, Chenxi Qian, Nicholas Golda, Heather K Hunt
BACKGROUND AND OBJECTIVE: Applications of light-based energy devices involving optical targets within the dermis frequently experience negative side-effects resultant from surface scattering and excess optical absorption by epidermal melanin. As a broadband optical absorber, melanin decreases the efficacy of light-based treatments throughout the ultraviolet, visible, and near-infrared spectra while also generating additional heat within the surface tissue that can lead to inflammation or tissue damage...
April 18, 2017: Lasers in Surgery and Medicine
https://www.readbyqxmd.com/read/28394085/dual-echo-epi-sequence-for-integrated-distortion-correction-in-3d-time-resolved-hyperpolarized-13-c-mri
#18
Benjamin J Geraghty, Justin Y C Lau, Albert P Chen, Charles H Cunningham
PURPOSE: To provide built-in off-resonance correction in time-resolved, volumetric hyperpolarized (13) C metabolic imaging by implementing a novel dual-echo 3D echo-planar imaging (EPI) sequence and reconstruction. METHODS: A spectral-spatial pulse for single-resonance excitation followed by a dual-echo 3D EPI readout was implemented to provide 64 × 8 × 6 cm(3) coverage at 5 × 5 × 5 mm(3) nominal resolution. Multiple sources of EPI distortions were encoded using a multi-echo (1) H EPI reference scan...
April 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28381021/handheld-free-space-quantum-key-distribution-with-dynamic-motion-compensation
#19
Hyunchae Chun, Iris Choi, Grahame Faulkner, Larry Clarke, Bryan Barber, Glenn George, Colin Capon, Antti Niskanen, Joachim Wabnig, Dominic O'Brien, David Bitauld
Mobile devices have become an inseparable part of our everyday life. They are used to transmit an ever-increasing amount of sensitive health, financial and personal information. This exposes us to the growing scale and sophistication of cyber-attacks. Quantum Key Distribution (QKD) can provide unconditional and future-proof data security but implementing it for handheld mobile devices comes with specific challenges. To establish security, secret keys of sufficient length need to be transmitted during the time of a handheld transaction (~1s) despite device misalignment, ambient light and user's inevitable hand movements...
March 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28372047/detection-of-forward-scattering-from-an-intruder-in-a-dynamic-littoral-environment
#20
Bo Lei, Yixin Yang, Kunde Yang, Yuanliang Ma
Forward scattering always occurs when an intruder moves into an underwater area between a source and a receiver. The detection of this forward-scattered signal is a challenge because a strong direct blast overwhelms the forward-scattered signal. Accordingly, an adaptive scheme for detecting the forward scattering introduced by an intruder in dynamic shallow water is proposed in this study. A short pulse was transmitted repeatedly in the water. The recorded direct blast and forward-scattered signal were assumed to be weakly correlated...
March 2017: Journal of the Acoustical Society of America
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