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pulse transmit time

David Perez-Diaz-de-Cerio, Ángela Hernández-Solana, Antonio Valdovinos, Jose Luis Valenzuela
Timing points used in running races and other competition events are generally based on radio-frequency identification (RFID) technology. Athletes' times are calculated via passive RFID tags and reader kits. Specifically, the reader infrastructure needed is complex and requires the deployment of a mat or ramps which hide the receiver antennae under them. Moreover, with the employed tags, it is not possible to transmit additional and dynamic information such as pulse or oximetry monitoring, alarms, etc. In this paper we present a system based on two low complex schemes allowed in Bluetooth Low Energy (BLE): the non-connectable undirected advertisement process and a modified version of scannable undirected advertisement process using the new capabilities present in Bluetooth 5...
March 20, 2018: Sensors
Anyun Zhang, Yunxia Li, Zhongbin Guan, Hongmei Tuo, Dan Liu, Yanxian Yang, Changwen Xu, Changwei Lei, Hongning Wang
The aim of this study was to evaluate the influence of apramycin administration on the development of antibiotic resistance in Escherichia coli ( E. coli ) strains isolated from chicken feces and houseflies under field conditions. Chickens in the medicated group ( n = 25,000) were given successive prophylactic doses (0.5 mg/l) of apramycin in their drinking water from Days 1 to 5, while no antibiotics were added to the un-medicated groups drinking water ( n = 25,000). Over 40 days, a total of 1170 E. coli strains were isolated from fecal samples obtained from medicated and un-medicated chickens and houseflies from the same chicken farm...
2018: Frontiers in Microbiology
Jing Xu, Ning Ding, Xilong Zhang, Nana Wang, Bing Sun, Rong Zhang, Xiaochen Xie, Zongren Wan, Yanli Gu, Shan Zhang, Yongqing Hong, Mao Huang, Zili Meng
PURPOSE: Obstructive sleep apnea syndrome (OSAS) can induce dramatic blood pressure (BP) fluctuations during sleep and it can be associated with hypertension. We investigated the properties and associated influential factors of BP fluctuation in severe OSAS with and without hypertension. METHODS: Two hundred one severe OSAS subjects were divided into hypertensive and normotensive groups. BP was continuously monitored via measurement of pulse transmit time (PTT)...
March 9, 2018: Sleep & Breathing, Schlaf & Atmung
Robert K Katzschmann, Brandon Araki, Daniela Rus
This paper presents ALVU (Array of Lidars and Vibrotactile Units), a contactless, intuitive, hands-free, and discreet wearable device that allows visually impaired users to detect low- and high-hanging obstacles, as well as physical boundaries in their immediate environment. The solution allows for safe local navigation in both confined and open spaces by enabling the user to distinguish free space from obstacles. The device presented is composed of two parts: a sensor belt and a haptic strap. The sensor belt is an array of time-of-flight distance sensors worn around the front of a user's waist, and the pulses of infrared light provide reliable and accurate measurements of the distances between the user and surrounding obstacles or surfaces...
March 2018: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Arian Beqiri, Hans Hoogduin, Alessandro Sbrizzi, Joseph V Hajnal, Shaihan J Malik
PURPOSE: Image quality obtained for brain imaging at 7T can be hampered by inhomogeneities in the static magnetic field, B0 , and the RF electromagnetic field, B1 . In imaging sequences such as fluid-attenuated inversion recovery (FLAIR), which is used to assess neurological disorders, these inhomogeneities cause spatial variations in signal that can reduce clinical efficacy. In this work, we aim to correct for signal inhomogeneities to ensure whole-brain coverage with 3D FLAIR at 7T...
February 24, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Brian C Grubel, Bryan T Bosworth, Michael R Kossey, A Brinton Cooper, Mark A Foster, Amy C Foster
We present a secure communication system constructed using pairs of nonlinear photonic physical unclonable functions (PUFs) that harness physical chaos in integrated silicon micro-cavities. Compared to a large, electronically stored one-time pad, our method provisions large amounts of information within the intrinsically complex nanostructure of the micro-cavities. By probing a micro-cavity with a rapid sequence of spectrally-encoded ultrafast optical pulses and measuring the lightwave responses, we experimentally demonstrate the ability to extract 2...
February 19, 2018: Optics Express
Mark T Burgess, Iason Zacharias Apostolakis, Elisa E Konofagou
Image-guided monitoring of microbubble-based focused ultrasound (FUS) therapies relies on the accurate localization of FUS-stimulated microbubble activity (i.e. acoustic cavitation). Passive cavitation imaging with ultrasound arrays can achieve this, but with insufficient spatial resolution. In this study, we address this limitation and perform high-resolution monitoring of acoustic cavitation-mediated blood-brain barrier (BBB) opening with a new technique called power cavitation imaging. By synchronizing the FUS transmit and passive receive acquisition, high-resolution passive cavitation imaging was achieved by using delay and sum (DAS) beamforming with absolute time delays...
February 19, 2018: Physics in Medicine and Biology
Ping Gong, Pengfei Song, Shigao Chen
Contrast-enhanced ultrasound (CEUS) imaging has great potential for use in new ultrasound clinical applications such as myocardial perfusion imaging and abdominal lesion characterization. In CEUS imaging, contrast agents (i.e., microbubbles) are used to improve contrast between blood and tissue because of their high nonlinearity under low ultrasound pressure. However, the quality of CEUS imaging sometimes suffers from a low signal-to-noise ratio (SNR) in deeper imaging regions when a low mechanical index (MI) is used to avoid microbubble disruption, especially for imaging at off-resonance transmit frequencies...
February 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Kyoung-Yong Chun, Young Jun Son, Eun-Seok Jeon, Sehan Lee, Chang-Soo Han
Highly efficient human skin systems transmit fast adaptive (FA) and slow adaptive (SA) pulses selectively or consolidatively to the brain for a variety of external stimuli. The integrated analysis of these signals determines how humans perceive external physical stimuli. Here, a self-powered mechanoreceptor sensor based on an artificial ion-channel system combined with a piezoelectric film is presented, which can simultaneously implement FA and SA pulses like human skin. This device detects stimuli with high sensitivity and broad frequency band without external power...
February 9, 2018: Advanced Materials
Murat Kuscu, Ozgur B Akan
We consider a microfluidic molecular communication (MC) system, where the concentration-encoded molecular messages are transported via fluid flow-induced convection and diffusion, and detected by a surface-based MC receiver with ligand receptors placed at the bottom of the microfluidic channel. The overall system is a convection-diffusion-reaction system that can only be solved by numerical methods, e.g., finite element analysis (FEA). However, analytical models are key for the information and communication technology (ICT), as they enable an optimisation framework to develop advanced communication techniques, such as optimum detection methods and reliable transmission schemes...
2018: PloS One
Milad Zamani, Yasser Rezaeiyan, Omid Shoaei, Wouter A Serdijn
This paper presents an implantable bio-impedance measurement system for cardiac pacemakers. The fully integrated system features a low power analog front-end and pulse width modulated output. The bio-impedance readout benefits from voltage to time conversion to achieve a very low power consumption for wirelessly transmitting the data outside the body. The proposed IC is fabricated in a 0.18 μm CMOS process and is capable of measuring the bio-impedance at 2 kHz over a wide dynamic range from to with accuracy and maximum current injection while consuming just from a 1 V supply...
February 2018: IEEE Transactions on Biomedical Circuits and Systems
I Ughratdar, K A Kawsar, R Mitchell, R Selway, K Ashkan
BACKGROUND: Battery replacement or revision surgery for neuromodulation implants is conventionally performed using sharp dissection. Meticulous dissection within thick scar tissue is vital to avoid damage to surrounding lead(s) which could result in more extensive revision surgery. Traditional electrosurgery devices are contraindicated as the emitted energy can be transferred to the hardware resulting in implant or tissue damage with severe consequent complications. OBJECTIVE: We report our experience and potential applications of a novel, pulsed monopolar radiofrequency energy device (PEAK PlasmaBlade™, Medtronic plc) which facilitates dissection around implants without the risk of damaging or transmitting energy through the system...
January 9, 2018: World Neurosurgery
Heather V Kenny, Amber N Wright, Jonah Piovia-Scott, Louie H Yang, David A Spiller, Thomas W Schoener
Resource pulses are brief periods of unusually high resource abundance. While population and community responses to resource pulses have been relatively well studied, how individual consumers respond to resource pulses has received less attention. Local consumers are often the first to respond to a resource pulse, and the form and timing of individual responses may influence how the effects of the pulse are transmitted throughout the community. Previous studies in Bahamian food webs have shown that detritivores associated with pulses of seaweed wrack provide an alternative prey source for lizards...
December 2017: Ecology and Evolution
Martin Pekař, Nenad Mihajlović, Harm Belt, Alexander F Kolen, Jeannet van Rens, Frank Budzelaar, Bas Jacobs, Johan G Bosch, Hendrik J Vos, Debbie Rem-Bronneberg, Gijs van Soest, Antonius F W van der Steen
Commercially available intracardiac echo (ICE) catheters face a trade-off between viewing depth and resolution. Frequency-tunable ICE probes would offer versatility of choice between penetration or resolution imaging within a single device. In this phantom study, the imaging performance of a novel, frequency-tunable, 32-element, 1-D CMUT array integrated with front-end electronics is evaluated. Phased-array ultrasound imaging with a forward-looking CMUT probe prototype operated beyond collapse mode at voltages up to three times higher than the collapse voltage (-65 V) is demonstrated...
December 14, 2017: Ultrasonics
Keren Constantini, Abigail S L Stickford, Jeffery L Bleich, Paul D Mannheimer, Benjamin D Levine, Robert F Chapman
Timing foot strike to occur in synchrony with cardiac diastole may reduce left ventricular afterload and promote coronary and skeletal muscle perfusion. PURPOSE: To assess heart rate (HR) and metabolic responses to running when foot strikes are timed to occur exclusively during 1) the systolic phase of the cardiac cycle, or 2) the diastolic phase. METHODS: Ten elite male distance runners performed a testing session on a treadmill at 4.72 m[BULLET OPERATOR]s while matching their steps to an auditory tone and wearing a chest strap that transmitted accelerometer and ECG signals...
December 12, 2017: Medicine and Science in Sports and Exercise
Vincent Gras, Franck Mauconduit, Alexandre Vignaud, Alexis Amadon, Denis Le Bihan, Tony Stöcker, Nicolas Boulant
PURPOSE: T2 -weighted sequences are particularly sensitive to the radiofrequency (RF) field inhomogeneity problem at ultra-high-field because of the errors accumulated by the imperfections of the train of refocusing pulses. As parallel transmission (pTx) has proved particularly useful to counteract RF heterogeneities, universal pulses were recently demonstrated to save precious time and computational efforts by skipping B1 calibration and online RF pulse tailoring. Here, we report a universal RF pulse design for non-selective refocusing pulses to mitigate the RF inhomogeneity problem at 7T in turbo spin-echo sequences with variable flip angles...
November 29, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Vyacheslav A Trofimov, Svetlana A Varentsova, Irina G Zakharova, Dmitry Yu Zagursky
Using an experiment with thin paper layers and computer simulation, we demonstrate the principal limitations of standard Time Domain Spectroscopy (TDS) based on using a broadband THz pulse for the detection and identification of a substance placed inside a disordered structure. We demonstrate the spectrum broadening of both transmitted and reflected pulses due to the cascade mechanism of the high energy level excitation considering, for example, a three-energy level medium. The pulse spectrum in the range of high frequencies remains undisturbed in the presence of a disordered structure...
November 25, 2017: Sensors
Min-Oh Kim, Taehwa Hong, Dong-Hyun Kim
PURPOSE: To develop a B1 + mapping during the transient phase of balanced steady state free precession (bSSFP) imaging which can be used for subsequent B1 + inhomogeneity compensation. METHODS: Two images with different flip angles (FA) are acquired using single-shot spiral technique during the transient phase of bSSFP with three consecutive RF pulses and balanced gradients. Under the assumptions that the transmit (B1 + ) field varies slowly in spatial domain and T1 and T2 relaxation effects are negligible during 2·TR, B1 + was estimated using the two magnitude images and bSSFP data was sequentially acquired...
February 2018: Magnetic Resonance Imaging
Bo-Dong Peng, Yan Song, Dong-Wei Hei, Jun Zhao
For the quantitative investigation of MeV-photon-induced changes in the refractive indices of bulk semiconductors, a model was established to describe the evolution of the excess carrier density, including the generation and recombination processes. The two key parameters of the evolution model, namely, the summed injection intensity and the gamma intensity curve, were obtained via dose measurements and gamma pulse monitoring, respectively. An interferometric method of measuring instantaneous changes in the refractive index and obtaining real-time measurements of the excess carrier density in bulk materials was successfully implemented...
October 2017: Review of Scientific Instruments
Dieter Rank, Stefan Wyhlidal, Katharina Schott, Silvia Weigand, Armin Oblin
The Austrian network of isotopes in rivers comprises about 15 sampling locations and has been operated since 1976. The Danube isotope time series goes back to 1963. The isotopic composition of river water in Central Europe is mainly governed by the isotopic composition of precipitation in the catchment area; evaporation effects play only a minor role. Short-term and long-term isotope signals in precipitation are thus transmitted through the whole catchment. The influence of climatic changes has become observable in the long-term stable isotope time series of precipitation and surface waters...
October 28, 2017: Isotopes in Environmental and Health Studies
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